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Zhuang M, Li F, Liang H, Su Y, Cheng L, Lin B, Zhou J, Deng R, Chen L, Lyu P, Lu Z. Targeting RCC1 to block the human soft-tissue sarcoma by disrupting nucleo-cytoplasmic trafficking of Skp2. Cell Death Dis 2024; 15:241. [PMID: 38561375 PMCID: PMC10985091 DOI: 10.1038/s41419-024-06629-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 03/16/2024] [Accepted: 03/21/2024] [Indexed: 04/04/2024]
Abstract
Soft-tissue sarcomas (STS) emerges as formidable challenges in clinics due to the complex genetic heterogeneity, high rates of local recurrence and metastasis. Exploring specific targets and biomarkers would benefit the prognosis and treatment of STS. Here, we identified RCC1, a guanine-nucleotide exchange factor for Ran, as an oncogene and a potential intervention target in STS. Bioinformatics analysis indicated that RCC1 is highly expressed and correlated with poor prognosis in STS. Functional studies showed that RCC1 knockdown significantly inhibited the cell cycle transition, proliferation and migration of STS cells in vitro, and the growth of STS xenografts in mice. Mechanistically, we identified Skp2 as a downstream target of RCC1 in STS. Loss of RCC1 substantially diminished Skp2 abundance by compromising its protein stability, resulting in the upregulation of p27Kip1 and G1/S transition arrest. Specifically, RCC1 might facilitate the nucleo-cytoplasmic trafficking of Skp2 via direct interaction. As a result, the cytoplasmic retention of Skp2 would further protect it from ubiquitination and degradation. Notably, recovery of Skp2 expression largely reversed the phenotypes induced by RCC1 knockdown in STS cells. Collectively, this study unveils a novel RCC1-Skp2-p27Kip1 axis in STS oncogenesis, which holds promise for improving prognosis and treatment of this formidable malignancy.
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Affiliation(s)
- Mingzhi Zhuang
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China
| | - Fengyue Li
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China
| | - Hong Liang
- College of Geography and Oceanography, Fuzhou Institute of Oceanography, Minjiang University, Fuzhou, Fujian, 350108, P. R. China
| | - Yongfu Su
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China
| | - Lei Cheng
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China
| | - Bingkai Lin
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China
| | - Jun Zhou
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China
| | - Runzhi Deng
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China
| | - Linying Chen
- Department of Pathology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, 350005, P. R. China
| | - Peng Lyu
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China.
| | - Zhonglei Lu
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China.
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Targeting the untargetable: RB1-deficient tumours are vulnerable to Skp2 ubiquitin ligase inhibition. Br J Cancer 2022; 127:969-975. [PMID: 35752713 PMCID: PMC9470583 DOI: 10.1038/s41416-022-01898-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/08/2022] [Accepted: 06/14/2022] [Indexed: 11/08/2022] Open
Abstract
Proteins that regulate the cell cycle are accumulated and degraded in a coordinated manner during the transition from one cell cycle phase to the next. The rapid loss of a critical protein, for example, to allow the cell to move from G1/G0 to S phase, is often regulated by its ubiquitination and subsequent proteasomal degradation. Protein ubiquitination is mediated by a series of three ligases, of which the E3 ligases provide the specificity for a particular protein substrate. One such E3 ligase is SCFSkp1/Cks1, which has a substrate recruiting subunit called S-phase kinase-associated protein 2 (Skp2). Skp2 regulates cell proliferation, apoptosis, and differentiation, can act as an oncogene, and is overexpressed in human cancer. A primary target of Skp2 is the cyclin-dependent kinase inhibitor p27 (CDKN1b) that regulates the cell cycle at several points. The RB1 tumour suppressor gene regulates Skp2 activity by two mechanisms: by controlling its mRNA expression, and by an effect on Skp2's enzymatic activity. For the latter, the RB1 protein (pRb) directly binds to the substrate-binding site on Skp2, preventing protein substrates from being ubiquitinated and degraded. Inactivating mutations in RB1 are common in human cancer, becoming more frequent in aggressive, metastatic, and drug-resistant tumours. Hence, RB1 mutation leads to the loss of pRb, an unrestrained increase in Skp2 activity, the unregulated decrease in p27, and the loss of cell cycle control. Because RB1 mutations lead to the loss of a functional protein, its direct targeting is not possible. This perspective will discuss evidence validating Skp2 as a therapeutic target in RB1-deficient cancer.
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Cai Z, Moten A, Peng D, Hsu CC, Pan BS, Manne R, Li HY, Lin HK. The Skp2 Pathway: A Critical Target for Cancer Therapy. Semin Cancer Biol 2020; 67:16-33. [PMID: 32014608 DOI: 10.1016/j.semcancer.2020.01.013] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/22/2020] [Accepted: 01/25/2020] [Indexed: 12/16/2022]
Abstract
Strictly regulated protein degradation by ubiquitin-proteasome system (UPS) is essential for various cellular processes whose dysregulation is linked to serious diseases including cancer. Skp2, a well characterized component of Skp2-SCF E3 ligase complex, is able to conjugate both K48-linked ubiquitin chains and K63-linked ubiquitin chains on its diverse substrates, inducing proteasome mediated proteolysis or modulating the function of tagged substrates respectively. Overexpression of Skp2 is observed in various human cancers associated with poor survival and adverse therapeutic outcomes, which in turn suggests that Skp2 engages in tumorigenic activity. To that end, the oncogenic properties of Skp2 are demonstrated by various genetic mouse models, highlighting the potential of Skp2 as a target for tackling cancer. In this article, we will describe the downstream substrates of Skp2 as well as upstream regulators for Skp2-SCF complex activity. We will further summarize the comprehensive oncogenic functions of Skp2 while describing diverse strategies and therapeutic platforms currently available for developing Skp2 inhibitors.
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Affiliation(s)
- Zhen Cai
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA.
| | - Asad Moten
- National Capital Consortium, Department of Defense, Washington DC, 20307, USA; Institute for Complex Systems, HealthNovations International, Houston, TX, 77089, USA; Center for Cancer Research, National Institutes of Health, Bethesda, MD, 20814, USA; Center on Genomics, Vulnerable Populations, and Health Disparities, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Danni Peng
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA
| | - Che-Chia Hsu
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA
| | - Bo-Syong Pan
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA
| | - Rajeshkumar Manne
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA
| | - Hong-Yu Li
- University of Arkansas for Medical Sciences, College of Pharmacy, Division of Pharmaceutical Science, 200 South Cedar, Little Rock AR 72202, USA
| | - Hui-Kuan Lin
- Department of Cancer Biology, Wake Forest Baptist Medical Center, Wake Forest University, Winston Salem, NC, 27101, USA; Graduate Institute of Basic Medical Science, China Medical University, Taichung 404, Taiwan; Department of Biotechnology, Asia University, Taichung 41354, Taiwan.
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USP10 modulates the SKP2/Bcr-Abl axis via stabilizing SKP2 in chronic myeloid leukemia. Cell Discov 2019; 5:24. [PMID: 31044085 PMCID: PMC6488640 DOI: 10.1038/s41421-019-0092-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 03/15/2019] [Accepted: 03/15/2019] [Indexed: 12/30/2022] Open
Abstract
Constitutive activation of tyrosine kinase Bcr-Abl is the leading cause of the development and progression of chronic myeloid leukemia (CML). Currently, the application of tyrosine kinase inhibitors (TKIs) targeting the Bcr-Abl is the primary therapy for CML patients. However, acquired resistance to TKIs that develops overtime in the long-term administration renders TKIs ineffective to patients with advanced CML. Therefore, increasing studies focus on the amplified expression or activation of Bcr-Abl which is proposed to contribute to the advanced phase. Here, we show that S-phase kinase-associated protein 2 (SKP2) acts as a co-regulator of Bcr-Abl by mediating its K63-linked ubiquitination and activation. Further investigations show that USP10 as a novel deubiquitinase of SKP2 amplifies the activation of Bcr-Abl via mediating deubiquitination and stabilization of SKP2 in CML cells. Moreover, inhibition of USP10 significantly suppresses the proliferation of both imatinib-sensitive and imatinib-resistant CML cells, which likely depends on SKP2 status. This findings are confirmed in primary CML cells because these cells are over-expressed with USP10 and SKP2 and are sensitive to a USP10 inhibitor. Taken together, the present study not only provides a novel insight into the amplified activation of Bcr-Abl in CML, but also demonstrates that targeting the USP10/SKP2/Bcr-Abl axis is a potential strategy to overcome imatinib resistance in CML patients.
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Integrated genomic analyses identify frequent gene fusion events and VHL inactivation in gastrointestinal stromal tumors. Oncotarget 2016; 7:6538-51. [PMID: 25987131 PMCID: PMC4872731 DOI: 10.18632/oncotarget.3731] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/10/2015] [Indexed: 01/17/2023] Open
Abstract
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. We sequenced nine exomes and transcriptomes, and two genomes of GISTs for integrated analyses. We detected 306 somatic variants in nine GISTs and recurrent protein-altering mutations in 29 genes. Transcriptome sequencing revealed 328 gene fusions, and the most frequently involved fusion events were associated with IGF2 fused to several partner genes including CCND1, FUS, and LASP1. We additionally identified three recurrent read-through fusion transcripts: POLA2-CDC42EP2, C8orf42-FBXO25, and STX16-NPEPL1. Notably, we found intragenic deletions in one of three exons of the VHL gene and increased mRNAs of VEGF, PDGF-β, and IGF-1/2 in 56% of GISTs, suggesting a mechanistic link between VHL inactivation and overexpression of hypoxia-inducible factor target genes in the absence of hypoxia. We also identified copy number gain and increased mRNA expression of AMACR, CRIM1, SKP2, and CACNA1E. Mapping of copy number and gene expression results to the KEGG pathways revealed activation of the JAK-STAT pathway in small intestinal GISTs and the MAPK pathway in wild-type GISTs. These observations will allow us to determine the genetic basis of GISTs and will facilitate further investigation to develop new therapeutic options.
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Kim JY, Kim HJ, Park JH, Park DI, Cho YK, Sohn CI, Jeon WK, Kim BI, Kim DH, Chae SW, Sohn JH. Epidermal growth factor upregulates Skp2/Cks1 and p27(kip1) in human extrahepatic cholangiocarcinoma cells. World J Gastroenterol 2014; 20:755-773. [PMID: 24574749 PMCID: PMC3921485 DOI: 10.3748/wjg.v20.i3.755] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 09/27/2013] [Accepted: 11/02/2013] [Indexed: 02/07/2023] Open
Abstract
AIM To evaluate the expression status of S-phase kinase-associated protein 2 (Skp2)/cyclin-dependent kinases regulatory subunit 1 (Cks1) and p27(kip1), and assess the prognostic significance of Skp2/Cks1 expression with p27(kip1) in patients with extrahepatic cholangiocarcinoma. METHODS Seventy-six patients who underwent curative resection for histologically confirmed extrahepatic cholangiocarcinoma at our institution from December 1994 to March 2008 were enrolled. Immunohistochemical staining for Skp2, Cks1, p27(kip1), and Ki67, along with other relevant molecular biologic experiments, were performed. RESULTS By Cox regression analyses, advanced age (> 65 years), advanced AJCC tumor stage, poorly differentiated histology, and higher immunostaining intensity of Skp2 were identified as independent prognostic factors in patients with extrahepatic cholangiocarcinoma. Exogenous epidermal growth factor (EGF, especially 0.1-10 ng/mL) significantly increased the proliferation indices by MTT assay and the mRNA levels of Skp2/Cks1 and p27(kip1) in SNU-1196, SNU-1079, and SNU-245 cells. The protein levels of Skp2/Cks1 (from nuclear lysates) and p27(kip1) (from cytosolic lysate) were also significantly increased in these cells. There were significant reductions in the protein levels of Skp2/Cks1 and p27(kip1) (from nuclear lysate) after the treatment of LY294002. By chromatin immunoprecipitation assay, we found that E2F1 transcription factor directly binds to the promoter site of Skp2. CONCLUSION Higher immunostaining intensity of Skp2/Cks1 was an independent prognostic factor for patients with extrahepatic cholangiocarcinoma. EGF upregulates the mRNA and protein levels of Skp2/Cks1 and p27(kip1) via the PI3K/Akt pathway and direct binding of E2F1 transcription factor with the Skp2 promoter.
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Li X, Bian Y, Takizawa Y, Hashimoto T, Ikoma T, Tanaka J, Kitamura N, Inagaki Y, Komada M, Tanaka T. ERK-Dependent Downregulation of Skp2 Reduces Myc Activity with HGF, Leading to Inhibition of Cell Proliferation through a Decrease in Id1 Expression. Mol Cancer Res 2013; 11:1437-47. [DOI: 10.1158/1541-7786.mcr-12-0718] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Cheng H, Meng J, Wang G, Meng Y, Li Y, Wei D, Fu C, Deng K, Shen A, Wang H, Dai S. Skp2 regulates subcellular localization of PPARγ by MEK signaling pathways in human breast cancer. Int J Mol Sci 2013; 14:16554-69. [PMID: 23939428 PMCID: PMC3759925 DOI: 10.3390/ijms140816554] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 07/15/2013] [Accepted: 07/19/2013] [Indexed: 11/16/2022] Open
Abstract
Nuclear hormone receptor family member PPARγ plays an important role in mammary gland tumorigenesis. Previous studies have shown PPARγ has cytoplasmic activities upon tetradecanoyl phorbol acetate (TPA) stimulation. However, the clinical pathological significance of cytoplasmic PPARγ is not completely understood in human breast cancer. Skp2 is oncogenic, and its frequent amplification and overexpression correlated with the grade of malignancy. In this study, the role of cytoplasmic PPARγ and Skp2 expression was investigated in human breast cancer progression. Therefore, immunohistochemical analysis was performed on formalin-fixed paraffin sections of 70 specimens. Furthermore, Western blot and immunofluorescence microscopy analysis were used to study the relationship between expression of cytoplasmic PPARγ and Skp2 expression in human breast cancer cells in vitro. Results showed that the expression of cytoplasmic PPARγ was positively correlated with Skp2 expression (p < 0.05), and correlated significantly with estrogen receptor (p = 0.026) and pathological grade (p = 0.029), respectively. In addition, Skp2 overexpression can provoke cytoplasmic localization of PPARγ upon MEK1-dependent mechanisms in human breast cancer cells by nuclear-cytosolic fractionation technology and immunofluorescence microscopy analysis. Using RNA interference technology, we also found that down-regulated Skp2 reduced the phosphorylation level of MEK1 and significantly reversed TPA-induced nuclear export of PPARγ in MDA-MB-231 cells. The changes in the subcellular localization of PPARγ may represent a novel target for selective interference in patients with breast cancer.
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Affiliation(s)
- Hongge Cheng
- Department of Laboratory Science, the Fourth Hospital Affiliated to Guangxi Medical University, Liuzhou 545005, Guangxi, China; E-Mails: (H.C.); (J.M.); (G.W.); (Y.M.); (Y.L.); (D.W.); (C.F.); (K.D.)
| | - Jie Meng
- Department of Laboratory Science, the Fourth Hospital Affiliated to Guangxi Medical University, Liuzhou 545005, Guangxi, China; E-Mails: (H.C.); (J.M.); (G.W.); (Y.M.); (Y.L.); (D.W.); (C.F.); (K.D.)
| | - Guisheng Wang
- Department of Laboratory Science, the Fourth Hospital Affiliated to Guangxi Medical University, Liuzhou 545005, Guangxi, China; E-Mails: (H.C.); (J.M.); (G.W.); (Y.M.); (Y.L.); (D.W.); (C.F.); (K.D.)
| | - Yuming Meng
- Department of Laboratory Science, the Fourth Hospital Affiliated to Guangxi Medical University, Liuzhou 545005, Guangxi, China; E-Mails: (H.C.); (J.M.); (G.W.); (Y.M.); (Y.L.); (D.W.); (C.F.); (K.D.)
| | - Yu Li
- Department of Laboratory Science, the Fourth Hospital Affiliated to Guangxi Medical University, Liuzhou 545005, Guangxi, China; E-Mails: (H.C.); (J.M.); (G.W.); (Y.M.); (Y.L.); (D.W.); (C.F.); (K.D.)
| | - Dong Wei
- Department of Laboratory Science, the Fourth Hospital Affiliated to Guangxi Medical University, Liuzhou 545005, Guangxi, China; E-Mails: (H.C.); (J.M.); (G.W.); (Y.M.); (Y.L.); (D.W.); (C.F.); (K.D.)
| | - Chunyun Fu
- Department of Laboratory Science, the Fourth Hospital Affiliated to Guangxi Medical University, Liuzhou 545005, Guangxi, China; E-Mails: (H.C.); (J.M.); (G.W.); (Y.M.); (Y.L.); (D.W.); (C.F.); (K.D.)
| | - Kaifeng Deng
- Department of Laboratory Science, the Fourth Hospital Affiliated to Guangxi Medical University, Liuzhou 545005, Guangxi, China; E-Mails: (H.C.); (J.M.); (G.W.); (Y.M.); (Y.L.); (D.W.); (C.F.); (K.D.)
| | - Aiguo Shen
- Department of Immunology and Microbiology, Medical College of Nantong University, Nantong 226001, Jiangsu, China; E-Mail:
| | - Huimin Wang
- Medical Laboratory Center, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu, China
- Authors to whom correspondence should be addressed; E-Mails: (H.W.); (S.D.); Tel.: +86-513-8505-2102 (H.W.); +86-772-381-5334 (S.D.); Fax: +86-513-8505-2102 (H.W.); +86-772-383-7242 (S.D.)
| | - Shengming Dai
- Department of Laboratory Science, the Fourth Hospital Affiliated to Guangxi Medical University, Liuzhou 545005, Guangxi, China; E-Mails: (H.C.); (J.M.); (G.W.); (Y.M.); (Y.L.); (D.W.); (C.F.); (K.D.)
- Authors to whom correspondence should be addressed; E-Mails: (H.W.); (S.D.); Tel.: +86-513-8505-2102 (H.W.); +86-772-381-5334 (S.D.); Fax: +86-513-8505-2102 (H.W.); +86-772-383-7242 (S.D.)
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Lv A, Li Z, Tian X, Guan X, Zhao M, Dong B, Hao C. SKP2 high expression, KIT exon 11 deletions, and gastrointestinal bleeding as predictors of poor prognosis in primary gastrointestinal stromal tumors. PLoS One 2013; 8:e62951. [PMID: 23690967 PMCID: PMC3656858 DOI: 10.1371/journal.pone.0062951] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 03/27/2013] [Indexed: 12/26/2022] Open
Abstract
Background and Aims Considering the indication of adjuvant therapy, the recurrence risk for primary gastrointestinal stromal tumor (GIST) after surgery needs to be accurately estimated. However, current risk stratification schemes may still have room for improvement. This study seeks to analyze prognostic factors for primary GISTs from 3 aspects, including clinicopathological parameters, immunohistochemical biomarkers, and gene mutational status, and attempts to find novel valuable factors predicting the malignancy potential of GISTs. Methods Retrospective data from 114 primary GIST patients after R0 resection were collected. Clinicopathological data was obtained from medical records and re-evaluated. Immunohistochemical analysis was performed using the Tissue Microarray method for Ki67, p16, p27, p53, SKP2, CD133, and actin. KIT gene exons 9, 11, 13, and 17 and PDGFRα gene exons 12 and 18 were tested for mutations using PCR. Results Univariate analysis revealed the following factors as poor prognostic indicators for relapse-free survival with a median follow-up of 50 months: male gender, gastrointestinal bleeding, mitotic index >5/50HPFs, tumor size >5 cm, non-gastric site, necrosis, epithelioid or mixed cell type, surrounding tissue invasion, Ki67>5%, p16>20%, p53 index >10, SKP2>10%, and KIT exon 11 deletion. Besides mitotic index, tumor size and site, SKP2 high expression (RR = 2.91, 95% CI: 1.41–5.99, P = 0.004) and KIT exon 11 deletion (RR = 2.73, 95% CI: 1.04–7.16, P = 0.041) were also independent risk factors in multivariate analysis, with gastrointestinal bleeding also showing a trend towards significance (RR = 1.88, 95% CI: 0.98–3.64, P = 0.059). In addition, gastrointestinal bleeding and SKP2 high expression showed a good ability to stratify high-risk patients further. Conclusion Our results show that gastrointestinal bleeding, SKP2 high expression, and KIT exon 11 deletions may be useful indicators of high recurrence risk for primary GIST patients.
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Affiliation(s)
- Ang Lv
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Hepato-Pancreato-Biliary Surgery, Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing, People’s Republic of China
| | - Zhongwu Li
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Pathology, Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing, People’s Republic of China
| | - Xiuyun Tian
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Hepato-Pancreato-Biliary Surgery, Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing, People’s Republic of China
| | - Xiaoya Guan
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Hepato-Pancreato-Biliary Surgery, Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing, People’s Republic of China
| | - Min Zhao
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Center laboratory, Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing, People’s Republic of China
| | - Bin Dong
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Center laboratory, Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing, People’s Republic of China
| | - Chunyi Hao
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Hepato-Pancreato-Biliary Surgery, Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing, People’s Republic of China
- * E-mail:
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Benevenuto-de-Andrade BA, León JE, Carlos R, Delgado-Azañero W, Mosqueda-Taylor A, Paes-de-Almeida O. Immunohistochemical expression of Skp2 protein in oral nevi and melanoma. Med Oral Patol Oral Cir Bucal 2013; 18:e388-91. [PMID: 23385514 PMCID: PMC3668862 DOI: 10.4317/medoral.18781] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 11/11/2012] [Indexed: 11/24/2022] Open
Abstract
Objective: The aim of this study was to analyze the immunohistochemical expression of Skp2 protein in 38 oral nevi and 11 primary oral melanomas.
Study Design: Expression of this ubiquitin protein was evaluated by immunohistochemistry in 49 oral melanocytic lesions, including 38 intramucosal nevi and 11 primary oral melanomas. The labeling index (LI) was assessed considering the percentage of cells expressing nuclear positivity out of the total number of cells, counting 1000 cells per slide.
Results: Skp2 protein was rarely expressed in intramucosal nevi, in contrast to oral melanomas, which showed high levels of this protein.
Conclusion: These results indicate that Skp2 protein may play a role in the development and progression of oral melanomas, and it also could be useful as an immunohistochemical marker for differential diagnosis of oral benign and malignant melanocytic lesions.
Key words:Oral melanoma, oral nevi, Skp2, cell cycle, immunohistochemistry.
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Sorbye SW, Kilvaer TK, Valkov A, Donnem T, Smeland E, Al-Shibli K, Bremnes RM, Busund LT. Prognostic impact of Skp2, ER and PGR in male and female patients with soft tissue sarcomas. BMC Clin Pathol 2013; 13:9. [PMID: 23497154 PMCID: PMC3602168 DOI: 10.1186/1472-6890-13-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 03/08/2013] [Indexed: 12/02/2022] Open
Abstract
Background S-phase kinase-associated protein 2 (Skp2) is a member of mammalian F-box proteins. The purpose of this study is to clarify the prognostic significance of expression of Skp2 related to gender, estrogen receptor (ER) and progesterone receptor (PGR) in soft tissue sarcomas (STS). Skp2 has been demonstrated to display an oncogenic function since its overexpression has been observed in many human cancers. Optimized treatment of STS requires better identification of high-risk patients who will benefit from adjuvant therapy. The prognostic significance of Skp2 related to ER and PGR in STS has not been sufficiently investigated. Methods Tissue microarrays from 193 STS patients were constructed from duplicate cores of viable and representative neoplastic tumor areas. Immunohistochemistry was used to evaluate the expression of Skp2, ER and PGR. Results In univariate analyses, high tumor expression of Skp2 correlated (p = 0.050) with reduced disease-specific survival (DSS). In subgroup analyses expression of PGR in males (p = 0.010) and in patients older than 60 years (p = 0.043) were negative prognostic factors for DSS. Expression of ER in females was a positive prognostic factor for DSS (p = 0.041). In co-expression analyses in the whole cohort, low expression of Skp2 in combination with low expression of ER was positive for DSS (p = 0.049). In females high expression of Skp2 in combination with low expression of ER was a negative prognosticator (p = 0.021). In the multivariate analyses, age (p = 0.012), malignancy grade (p < 0.001), wide resection margins (P = 0.010), ER negative / PGR positive co-expression profile (p = 0.002) and ER positive / PGR negative co-expression profile (p = 0.015) were independent negative prognostic factors for DSS. In females expression of Skp2 (p = 0.006) was associated with shorter DSS. Conclusions We found diverse prognostic impacts of expression of Skp2, ER, PGR and DSS in male and female patients with STS. In men, but not women, ER positive / PGR negative co-expression profile was an independent negative prognostic factor for DSS. In women, but not men, high expression of Skp2 was associated with reduced DSS.
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Affiliation(s)
- Sveinung W Sorbye
- Department of Clinical Pathology, University Hospital of North Norway, Tromso, Norway.
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Sistrunk C, Kim SH, Wang X, Lee SH, Kim Y, Macias E, Rodriguez-Puebla ML. Skp2 deficiency inhibits chemical skin tumorigenesis independent of p27(Kip1) accumulation. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 182:1854-64. [PMID: 23474082 DOI: 10.1016/j.ajpath.2013.01.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 12/18/2012] [Accepted: 01/14/2013] [Indexed: 01/11/2023]
Abstract
S-phase kinase-associated protein 2 (Skp2) functions as the receptor component of the Skp-Cullin-F-box complex and is implicated in the degradation of several cell cycle regulators, such as p21(Cip1), p27(Kip1), p57(Kip2), and cyclin E. Numerous studies in human and experimental tumors have demonstrated low p27(Kip1) levels and elevated Skp2 expression. However, a direct association between the inverse correlation of Skp2 and p27(Kip1) with tumorigenesis has not been demonstrated. Herein, we provide evidence that skin tumorigenesis is inhibited in Skp2(-/-) mice. An analysis of mouse keratinocytes indicates that increased p27(Kip1) levels in Skp2(-/-) epidermis cause reduced cell proliferation that is alleviated in the epidermis from Skp2(-/-)/p27(-/-) compound mice. In contrast, we establish that a p27(Kip1) deficiency does not overturn the reduced skin tumorigenesis experienced by Skp2(-/-) mice. In addition, Skp2(-/-) epidermis exhibits an accumulation of p53-cofactor CBP/p300 that is associated with elevated apoptosis in hair follicles and decreased skin tumorigenesis. We conclude that p27(Kip1) accumulation is responsible for the hypoplasia observed in normal tissues of Skp2(-/-) mice but does not have a preponderant function in reducing skin tumorigenesis.
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Affiliation(s)
- Christopher Sistrunk
- Department of Molecular Biomedical Sciences and the Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA
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Sorbye SW, Kilvaer TK, Valkov A, Donnem T, Smeland E, Al-Shibli K, Bremnes RM, Busund LT. Prognostic impact of Jab1, p16, p21, p62, Ki67 and Skp2 in soft tissue sarcomas. PLoS One 2012; 7:e47068. [PMID: 23071715 PMCID: PMC3465267 DOI: 10.1371/journal.pone.0047068] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 09/07/2012] [Indexed: 01/12/2023] Open
Abstract
PURPOSE The purpose of this study is to clarify the prognostic significance of expression of Jab1, p16, p21, p62, Ki67 and Skp2 in soft tissue sarcomas (STS). Optimised treatment of STS requires better identification of high risk patients who will benefit from adjuvant therapy. The prognostic significance of Jab1, p16, p21, p62, Ki67 and Skp2 in STS has not been sufficiently investigated. EXPERIMENTAL DESIGN Tissue microarrays from 193 STS patients were constructed from duplicate cores of viable and representative neoplastic tumor areas. Immunohistochemistry was used to evaluate the expression of Jab1, p16, p21, p62, Ki67 and Skp2. RESULTS In univariate analyses, high tumor expression of Ki67 (P = 0.007) and Skp2 (P = 0.050) correlated with shorter disease-specific survival (DSS). In subgroup analysis, a correlation between Skp2 and DSS was seen in patients with malignancy grade 1 or 2 (P = 0.027), tumor size >5 cm (P = 0.018), no radiotherapy given (P = 0.029) and no chemotherapy given (P = 0.017). No such relationship was apparent for Jab1, p16, p21 and p62; but p62 showed a positive correlation to malignancy grade (P = 0.019). Ki67 was strongly positively correlated to malignancy grade (P = 0.001). In multivariate analyses, Skp2 was an independent negative prognostic factor for DSS in women (P = 0.009) and in patients without administered chemotherapy or radiotherapy (P = 0.026). CONCLUSIONS Increased expression of Skp2 in patients with soft tissue sarcomas is an independent negative prognostic factor for disease-specific survival in women and in patients not administered chemotherapy or radiotherapy. Besides, further studies are warranted to explore if adjuvant chemotherapy or radiotherapy improve the poor prognosis of STS with high Skp2 expression.
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Affiliation(s)
- Sveinung W Sorbye
- Department of Clinical Pathology, University Hospital of North Norway, Tromso, Norway.
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Jiang J, Jin MS, Suo J, Wang YP, He L, Cao XY. Evaluation of malignancy using Ki-67, p53, EGFR and COX-2 expressions in gastrointestinal stromal tumors. World J Gastroenterol 2012; 18:2569-75. [PMID: 22654456 PMCID: PMC3360457 DOI: 10.3748/wjg.v18.i20.2569] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 09/27/2011] [Accepted: 10/27/2011] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the role of expressions of Ki-67, p53, epidermal growth factor receptor (EGFR) and cyclooxygenase-2 (COX-2) in gastrointestinal stromal tumor (GIST) grading and prognosis. METHODS Tumor tissue was collected retrospectively from 96 patients with GIST. Antibodies against Ki-67, p53, EGFR and COX-2 were used for immunohistochemical staining. Tumor grading was designated according to a consensus system and the staining was quantified in 3 categories for each antibody in the statistical analysis. RESULTS The Ki-67 expression in GISTs was significantly associated with the size of the tumors, mitotic rate and the risk of malignancy (χ(2) = 15.51, P = 0.02; χ(2) = 22.27, P < 0.001; χ(2) = 20.05; P < 0.001). The p53 expression was also significantly correlated with mitotic rate and the risk of malignancy (χ(2) = 9.92, P = 0.04; χ(2) = 9.97; P = 0.04). Over-expression of Ki-67 was strongly correlated with poor survival (χ(2) = 10.44, P = 0.006), but no correlation was found between the expression of p53, EGFR or COX-2 and survival. Multivariate analysis further demonstrated that Ki-67 expression (relative risk = 15.78, 95% CI: 4.25-59.37) could be used as an independent prognostic value for GIST patients. Adjuvant imatinib therapy could improve clinical outcomes in the patients with high risk and intermediate risk of recurrence after complete tumor resections (median survival time: 52 mo vs 37 mo, χ(2) = 7.618, P = 0.006). CONCLUSION Our results indicated that the expression of Ki-67 could be used as an independent prognostic factor for GIST patients.
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The prognostic value of Skp2 expression in Egyptian diffuse large B-cell lymphoma. Appl Immunohistochem Mol Morphol 2012; 20:47-55. [PMID: 21558842 DOI: 10.1097/pai.0b013e318219a19f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma worldwide. Both morphologically and prognostically, it represents a disease of a diverse spectrum. S-phase kinase-associated protein 2 (Skp2) is a member of mammalian F-box proteins, which displays S-phase-promoting function through ubiquitin-mediated proteolysis of the cyclin-dependent kinase inhibitor, p27. The aim of this study is to evaluate the prognostic value of Skp2 in DLBCL (70 cases) by immunohistochemical staining technique, and its correlation with the clinicopathological features and survival. Five (25%) control cases (reactive follicular hyperplasia) showed high Skp2 expression compared with 52.9% of DLBCL using 10% as a cutoff point with a significant difference (P=0.04). Skp2 was seen staining the large cells in proliferating germinal centers of the control group. High Skp2 expression in DLBCL was associated with several progressive parameters, such as advanced stage (P=0.036), involvement of more than one extranodal site (P=0.05), and high proliferation (P=0.0001). It was also significantly associated with the presence (P=0.007) and extent (P=0.002) of necrosis and inversely correlated with p27 expression (P=0.0001). From this study, Skp2 expression in DLBCL identified subset of cases characterized by aggressive features such as advanced stage, increased number of extranodal sites, high proliferation, and shorter survival time. The association of Skp2 with necrosis may be a reflection of its ability in promoting proliferative tumor capacity.
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Arbini AA, Greco M, Yao JL, Bourne P, Marra E, Hsieh JT, di Sant'agnese PA, Moro L. Skp2 overexpression is associated with loss of BRCA2 protein in human prostate cancer. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2367-76. [PMID: 21514447 DOI: 10.1016/j.ajpath.2011.01.050] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 11/29/2010] [Accepted: 01/07/2011] [Indexed: 11/28/2022]
Abstract
BRCA2 (breast cancer 2, early onset) is a tumor suppressor gene that confers increased susceptibility for prostate cancer (PCa). Previous in vitro experiments demonstrated that Skp2, an E3 ubiquitin ligase aberrantly overexpressed in PCa, is involved in the proteolytic degradation of BRCA2 in PCa cells, suggesting that the BRCA2-Skp2 interaction may play a role in prostate tumorigenesis. Herein, we investigated BRCA2 and Skp2 expression during PCa development using a prostate TMA. Although luminal and basal benign prostate epithelium exhibited moderate to strong nuclear BRCA2 immunostaining, the intensity and number of positive nuclei decreased significantly in high-grade prostatic intraepithelial neoplasia and PCa. Decreased frequency and intensity of nuclear BRCA2 labeling were inversely correlated with Skp2 expression in high-grade prostatic intraepithelial neoplasia and PCa. To functionally assess the effects of BRCA2 and Skp2 expression on prostate malignant transformation, we overexpressed Skp2 in normal immortalized prostate cells. Skp2 overexpression reduced BRCA2 protein and promoted cell growth and migration. A similar phenotype was observed after reduction of BRCA2 protein levels using specific BRCA2 small-interfering RNA. Forced BRCA2 expression in Skp2-overexpressing stable transfectants inhibited the migratory and growth properties by >60%. These results show that loss of BRCA2 expression during prostate tumor development is strongly correlated with both migratory behavior and cancer growth and include Skp2 as a BRCA2 proteolytic partner in vivo.
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Affiliation(s)
- Arnaldo A Arbini
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Sirinian C, Symeonidis A, Giannakoulas N, Zolota V, Melachrinou M. Overexpression of phosphorylated p27 Kip1 at threonine 187 may predict outcome in aggressive B-cell lymphomas. Leuk Lymphoma 2011; 52:814-22. [PMID: 21338280 DOI: 10.3109/10428194.2011.555026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Phosphorylation of p27(Kip1) at threonine 187 (pThr187-p27(Kip1)) occurs frequently in the development of human tumors, directing protein polyubiquitination and subsequent proteasomal degradation. We investigated the immunoexpression of p27(Kip1) and pThr187-p27(Kip1) in 126 B-cell lymphomas and their relation to proliferative activity and clinical parameters. Increased levels of p27(Kip1) and pThr187-p27(Kip1) were significantly correlated with indolent and aggressive lymphomas, respectively (p < 0.001). pThr187-p27(Kip1) expression showed a strong positive correlation with proliferation index in aggressive (p = 0.01) and indolent (p < 0.001) subgroups. Survival analysis revealed that pThr187-p27(Kip1) was an unfavorable prognostic factor for disease-free (p = 0.019) and overall survival (p = 0.003) in aggressive lymphomas. Cox regression analysis demonstrated that the prognostic value of pThr187-p27(Kip1) was independent of the international prognostic index (IPI) score, tumor stage, patient age, and serum lactate dehydrogenase (LDH) level. Overall, our results suggest that high levels of pThr187-p27(Kip1) may predict a worse clinical outcome in patients with aggressive lymphomas.
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Affiliation(s)
- Chaido Sirinian
- Department of Pathology, Division of Hematology, University of Patras Medical School, Patras, Greece
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Chen JY, Wang MC, Hung WC. Bcr-Abl-induced tyrosine phosphorylation of Emi1 to stabilize Skp2 protein via inhibition of ubiquitination in chronic myeloid leukemia cells. J Cell Physiol 2010; 226:407-13. [DOI: 10.1002/jcp.22346] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Dysregulation of the ubiquitin-proteasome system (UPS) has been implicated in several types of tumorigenesis. Our previous studies have shown the potential role of Cdh1/APC in regulating tumor formation via governing the Skp2-p27-cyclinE/CDK2 axis. In this work, we used a xenograft mouse breast cancer model to identify the mechanism by which Cdh1/APC potentially suppresses tumor growth in vivo. Here, we report that depletion of Cdh1 results in a significant enhancement of the breast tumor proliferation, while elevated Cdh1 leads to suppression of breast tumor growth. Analysis of breast tissue arrays has indicated that higher levels of Cdh1 are associated with normal breast epithelial tissues whereas lower Skp2 expression and elevated p27 levels are detected. Conversely, the percentage of breast cancer tissues stained positive for Cdh1 and p27 are significantly lower with higher Skp2 levels. Thus, the E3 ligase, Cdh1/APC, may inhibit breast tumor growth via regulating Skp2-p27 mediated cell cycle progression.
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Affiliation(s)
- Takeo Fujita
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine and University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213, USA
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Chen JY, Wang MC, Hung WC. Transcriptional activation of Skp2 by BCR-ABL in K562 chronic myeloid leukemia cells. Leuk Res 2009; 33:1520-4. [PMID: 19329185 DOI: 10.1016/j.leukres.2009.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 03/03/2009] [Accepted: 03/07/2009] [Indexed: 10/21/2022]
Abstract
We addressed how BCR-ABL oncoprotein increased Skp2 expression. Treatment of Imatinib or LY294002 reduced Skp2 mRNA in BCR-ABL-positive K562 cells. Knockdown of AKT by small hairpin RNA also reduced Skp2 expression. We found that BCR-ABL up-regulated Skp2 via Sp1 because (1) the Sp1 site located at the -386/-380 promoter region was important for BCR-ABL-induced Skp2 promoter activity, (2) chromatin immunoprecipitation assay demonstrated that Imatinib inhibited the recruitment of p300 to the Sp1 site of Skp2 promoter and (3) knockdown of Sp1 reduced Skp2 expression in K562 cells. These results suggest that BCR-ABL controls Skp2 gene transcription via the PI3K/AKT/Sp1 pathway.
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Affiliation(s)
- Jing-Yi Chen
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan
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Fang FM, Chien CY, Li CF, Shiu WY, Chen CH, Huang HY. Effect of S-phase kinase-associated protein 2 expression on distant metastasis and survival in nasopharyngeal carcinoma patients. Int J Radiat Oncol Biol Phys 2009; 73:202-207. [PMID: 18538504 DOI: 10.1016/j.ijrobp.2008.04.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Revised: 04/06/2008] [Accepted: 04/07/2008] [Indexed: 11/18/2022]
Abstract
PURPOSE The S-phase kinase-associated protein 2 (Skp2) oncoprotein is an E3 ubiquitin ligase targeting the p27(Kip1) tumor suppressor for degradation. We evaluated the prognostic utility of Skp2 in nasopharyngeal carcinoma (NPC), with an emphasis on distant metastasis-free (DMF) survival. METHODS AND MATERIALS Immunohistochemical expression of Skp2 was assessed by H-score for 233 NPC patients without initial distant metastasis and correlated with the clinicopathologic features, therapeutic modalities, locoregional control rate, DMF survival, and overall survival (OS). No selection bias in essential parameters was shown between these and another 113 control patients. RESULTS Skp2 was detectable in most patients (95%) but displayed a wide range of expression. Despite no correlation between Skp2 and any clinicopathologic factor, greater Skp2 expression (H-score >80) significantly portended inferior DMF survival (p = 0.01) and OS (p = 0.02) when categorically dichotomizing the study cohort. The associations with DMF survival (p = 0.003) and OS (p = 0.003) became even stronger when the H-score was expressed as a continuous variable. In the multivariate model, greater Skp2 expression remained significantly predictive of poorer DMF survival and OS (p = 0.01 for both), along with T stage (p = 0.04 for DMF survival; p = 0.005 for OS), N stage (p = 0.008 for DMF survival; p = 0.02 for OS), and/or age (p = 0.001 for OS). In contrast, T stage (p = 0.01) was the single independent prognosticator of LCR. CONCLUSIONS The results of our study have shown that Skp2 expression is frequent in NPC and has a wide range of distribution in H-score. Skp2 overexpression is significantly predictive of DMF survival and OS, independent of the T stage and/or older age. Therefore, Skp2 might represent a useful prognostic adjunct to risk stratify NPC patients for appropriate allocation of adjuvant therapy.
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Affiliation(s)
- Fu-Min Fang
- Department of Radiation Oncology, Kaohsiung Chang Gung Head and Neck Oncology Group, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan
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Fujita T, Liu W, Doihara H, Date H, Wan Y. Dissection of the APCCdh1-Skp2 cascade in breast cancer. Clin Cancer Res 2008; 14:1966-75. [PMID: 18381934 DOI: 10.1158/1078-0432.ccr-07-1585] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Skp2 is a subunit of the SCF ubiquitin protein ligase, which plays a vital role in the control of tumorigenesis via its regulation of G(1)-S transition. Deregulation of Skp2 in various types of cancers correlates with aggressive clinical behavior and poor prognosis. Recent studies suggest that cell cycle-dependent fluctuation of Skp2 is governed by APC(Cdh1), another important E3 ligase, thereby preventing premature entry into S phase. To assess the potential role of APC(Cdh1) in tumorigenesis through proteolysis of Skp2, we have dissected the APC(Cdh1)-Skp2 cascade. EXPERIMENTAL DESIGN We manipulated the APC(Cdh1)-Skp2 cascade and examined its cellular behavior using both breast cancer and normal breast epithelial cells. Furthermore, applying immunohistochemistry, we analyzed the clinicopathologic significance of these molecules in patients with breast cancer. RESULTS Analysis of tissue arrays indicated that the percentage of samples positive for Cdh1 in breast cancer was significantly lower compared with normal breast tissues (P=0.004). Conversely, the percentage of samples scored as positive for Skp2 in cancer was significantly higher than in normal tissues (P<0.001). Moreover, prognostic studies revealed that relatively high levels of Cdh1 are associated with survivability in patients with breast cancer. In addition, depletion of Cdh1 by small interfering RNA in normal breast cells resulted in increased cellular proliferation, whereas knockdown of Skp2 significantly suppressed growth in breast cancer cells. CONCLUSIONS This study shows a correlation between Skp2 and APC(Cdh1) in breast cancer. Thus, Cdh1 may act as an important component in tumor suppression and could be considered as a novel biomarker in breast cancer.
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Affiliation(s)
- Takeo Fujita
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine and University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213, USA
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Fujita T, Liu W, Doihara H, Wan Y. Regulation of Skp2-p27 axis by the Cdh1/anaphase-promoting complex pathway in colorectal tumorigenesis. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 173:217-28. [PMID: 18535175 DOI: 10.2353/ajpath.2008.070957] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abrogated entry into S phase is a common hallmark of cancer cells. Skp2, a subunit of ubiquitin ligase, is critical for regulating the G(1)/S transition. Uncontrolled Skp2 activity is detected frequently in human tumors, often correlated with poor prognosis. Current studies have suggested that the regulation of Skp2 turnover is mediated by another critical ubiquitin ligase, the anaphase-promoting complex (APC), in association with its substrate-specific factor Cdh1. To dissect the potential role of Cdh1/APC in tumorigenesis through the degradation of Skp2, we analyzed the Cdh1/APC-Skp2-p27 axis in colorectal tumorigenesis using a human tumor array and biochemical analyses. Our results show that the percentage of Cdh1- and p27-positive samples in colon cancer tissues was significantly lower than that in adjacent nonmalignant tissue. Conversely, the percentage of Skp2-positive colon cancer samples was significantly higher than that in normal tissue. Furthermore, results from clinicopathological analysis revealed that elevated Cdh1 expression was associated with lower histological grade tumors. In addition, depletion of Cdh1 by RNA interference in nonmalignant colon cells resulted in increased cellular proliferation, whereas knockdown of Skp2 significantly suppressed cancer cell growth. Our result suggests a pathological correlation between Skp2 and Cdh1/APC in colorectal cancer. Thus, Cdh1 may function as a component in tumor suppression via proteolysis of Skp2 in colorectal tumorigenesis and may serve as a prognostic marker in colon cancer patients.
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Affiliation(s)
- Takeo Fujita
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine and University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213, USA
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Di Vizio D, Demichelis F, Simonetti S, Pettinato G, Terracciano L, Tornillo L, Freeman MR, Insabato L. Skp2 expression is associated with high risk and elevated Ki67 expression in gastrointestinal stromal tumours. BMC Cancer 2008; 8:134. [PMID: 18474118 PMCID: PMC2396636 DOI: 10.1186/1471-2407-8-134] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 05/13/2008] [Indexed: 11/17/2022] Open
Abstract
Background Gastrointestinal stromal tumors (GIST) exhibit an unpredictable clinical course and can rapidly progress to lethality. Predictions about the biological behavior of GIST are based on a number of canonical clinical and pathologic parameters whose validity in distinguishing between a benign and a malignant tumour is still imperfect. The aim of our study was to investigate the role of morphologic parameters and expression of cells cycle regulators as prognosticators in GIST. Methods We performed an immunohistochemical analysis for Ki67, p27Kip1, Jab1, and Skp2, on a Tissue Microarray (TMA) containing 94 GIST. Expression of the above proteins was correlated to classically used prognosticators, as well as to risk groups. Clinical significance of histologic and immunohistochemical features were evaluated in 59 patients for whom follow-up information was available. Results Overexpression of Ki67 and Skp2, and p27Kip1 loss directly correlated with the high risk group (p = 0.03 for Ki67 and Skp2, p = 0.05 for p27Kip1). Jab1 expression did not exhibit correlation with risk. In 59 cases provided with clinical follow-up, high cellularity, presence of necrosis, and Ki67 overexpression were predictive of a reduced overall survival in a univariate model. The same parameters, as well as mitotic rate, tumour size, and p27Kip1 loss were indicative of a shortened relapse free survival interval. High cellularity, and high mitotic rate retained their prognostic significance by multivariate analysis. Conclusion Our data suggest that a number of histologic parameters in combination with immunohistochemical expression of cell cycle regulators can facilitate risk categorization and predict biologic behavior in GIST. Importantly this study demonstrates, for the first time, that Skp2 expression correlates with Ki67 expression and high risk in GIST.
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Affiliation(s)
- Dolores Di Vizio
- Department of Functional and Biomorphological Science, University "Federico II", Naples, Italy.
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Hershko DD. Oncogenic properties and prognostic implications of the ubiquitin ligase Skp2 in cancer. Cancer 2008; 112:1415-24. [PMID: 18260093 DOI: 10.1002/cncr.23317] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The expression of Skp2, the ubiquitin ligase subunit that targets p27(Kip1) for degradation, is commonly overexpressed in human cancers. p27(Kip1) is a negative regulator of the cell cycle that plays an important role in tumor suppression. Loss of p27(Kip1) secondary to enhanced ubiquitin-mediated degradation results in uncontrolled proliferation and promotes tumor progression. In the present study the prognostic implications of Skp2 are reviewed and the mechanisms that regulate its expression in different human cancers. A review and analysis of the English literature was undertaken. Overexpression of Skp2 mRNA and protein levels was observed in many aggressive cancers and was commonly associated with down-regulation of p27(Kip1) levels and loss of tumor differentiation. Skp2 is an independent prognostic marker for disease-free and overall survival and may provide additional predictive information to that provided by p27(Kip1) alone. Targeting Skp2 in experimental models resulted in up-regulation of p27(Kip1) and arrested cellular proliferation. Alterations in Skp2 expression have profound effects on cancer progression and may serve as an accurate and independent prognostic marker. Thus, determination of levels of Skp2 and p27(Kip1) by readily available immunohistochemical studies may be a useful tool in the assessment of prognosis, especially in patients with intermediate disease, and may potentially assist in the planning of adjuvant therapy. Skp2 may be an attractive target for the development of novel interventional therapy.
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Affiliation(s)
- Dan D Hershko
- Department of Surgery and Breast Health Institute, Rambam Health Care Campus and the Technion-Israel Institute of Technology, Haifa, Israel.
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Boix-Perales H, Horan I, Wise H, Lin HR, Chuang LC, Yew PR, Philpott A. The E3 ubiquitin ligase skp2 regulates neural differentiation independent from the cell cycle. Neural Dev 2007; 2:27. [PMID: 18081928 PMCID: PMC2244796 DOI: 10.1186/1749-8104-2-27] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Accepted: 12/14/2007] [Indexed: 11/24/2022] Open
Abstract
Background The SCFskp2 complex is an E3 ubiquitin ligase that is known to target a number of cell cycle regulators, including cyclin-dependent kinase inhibitors, for proteolysis. While its role in regulation of cell division has been well documented, additional functions in differentiation, including in the nervous system, have not been investigated. Results Using Xenopus as a model system, here we demonstrate that skp2 has an additional role in regulation of differentiation of primary neurons, the first neurons to differentiate in the neural plate. Xenopus skp2 shows a dynamic expression pattern in early embryonic neural tissue and depletion of skp2 results in generation of extra primary neurons. In contrast, over-expression of skp2 inhibits neurogenesis in a manner dependent on its ability to act as part of the SCFskp2 complex. Moreover, inhibition of neurogenesis by skp2 occurs upstream of the proneural gene encoding NeuroD and prior to cell cycle exit. We have previously demonstrated that the Xenopus cyclin dependent kinase inhibitor Xic1 is essential for primary neurogenesis at an early stage, and before these cells exit the cell cycle. We show that SCFskp2 degrades Xic1 in embryos and this contributes to the ability of skp2 to regulate neurogenesis. Conclusion We conclude that the SCFskp2 complex has functions in the control of neuronal differentiation additional to its role in cell cycle regulation. Thus, it is well placed to be a co-ordinating factor regulating both cell proliferation and cell differentiation directly.
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Affiliation(s)
- Hector Boix-Perales
- Department of Oncology, University of Cambridge, Hutchison/MRC Research Centre, Addenbrookes Hospital, Hills Road, Cambridge CB2 0XZ, UK.
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Zhang K, Prichard JW, Yoder S, De J, Lin F. Utility of SKP2 and MIB-1 in grading follicular lymphoma using quantitative imaging analysis. Hum Pathol 2007; 38:878-82. [PMID: 17350668 DOI: 10.1016/j.humpath.2006.11.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 11/20/2006] [Accepted: 11/29/2006] [Indexed: 11/21/2022]
Abstract
Follicular lymphoma is classified into grades (G)1, 2, and 3 based on the number of centroblasts in neoplastic follicles. However, the accuracy of manually counting these centroblasts is limited by certain cells (large centrocytes, follicular dendritic cells, and histiocytes) that could mimic centroblast morphology. The reproducibility of follicular lymphoma grading is dependent upon observer experience; therefore, significant variations occur. This study is to explore a more objective, reliable way of grading follicular lymphoma using a quantitative imaging system in conjunction with immunostains with antibodies to proliferation markers MIB-1 and S-phase kinase-associated protein 2 (SKP2). Fifty-eight follicular lymphomas (G1, n = 23; G2, n = 18; and G3, n = 17) were studied on formalin-fixed, paraffin-embedded sections. Positive nuclear staining of both Ki-67 and SKP2 was recorded using the quantitative Clarient ACIS II system (Aliso Viejo, CA, USA). Ten high-power fields (x400) from randomly selected neoplastic follicles were counted by a pathologist blinded to the previously assigned morphologic grade. The results show that the percentages of Ki-67+ and SKP2+ cells significantly differ among the different grades of follicular lymphoma. A higher grade of follicular lymphoma is associated with a higher percentage of Ki-67+ and SKP2+ cells. The overall SKP2+% cells are substantially lower than Ki-67+% cells in the same grade of follicular lymphoma. Statistical significance is observed in Ki-67+ cells between follicular lymphoma G1 and follicular lymphoma G3 and between G1 and G2. In contrast, statistical significance is noted in SKP2+% cells between follicular lymphoma G1 and follicular lymphoma G3 and between follicular lymphoma G2 and follicular lymphoma G3. The findings suggest that the SKP2 expression has better discrimination with grades of follicular lymphoma than Ki-67 expression. Compared with traditional methods, quantitation of SKP2 expression using a quantitative image analysis system might be a useful and objective approach in grading follicular lymphoma.
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Affiliation(s)
- Kai Zhang
- Department of Laboratory Medicine, Geisinger Medical Center, Danville, PA 17822, USA
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Chen TP, Chen CM, Chang HW, Wang JS, Chang WC, Hsu SI, Cho CL. Increased expression of SKP2 and phospho-MAPK/ERK1/2 and decreased expression of p27 during tumor progression of cervical neoplasms. Gynecol Oncol 2007; 104:516-23. [PMID: 17079005 DOI: 10.1016/j.ygyno.2006.09.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Revised: 08/31/2006] [Accepted: 09/05/2006] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The objective of this study was to investigate whether the expression of SKP2, p27 and phospho-MAPK/ERK1/2 is associated with the progression of human cervical neoplasia. METHODS We performed immunohistochemical detection to stain formalin-fixed paraffin-embedded cervical tissues with anti-SKP2 and anti-p27 monoclonal antibodies and anti-phospho-p42/44 MAPK antibody. The study sample included 23 normal cervical epithelium, 25 low-grade squamous intraepithelial lesion (LSIL), 19 high-grade squamous intraepithelial lesion (HSIL), and 31 squamous cell carcinomas (SCC). In addition, 14 frozen cervical biopsies, including 1 normal, 6 HSIL, 2 adenocarcinoma and 5 SCC, and a human cervical cancer cell line (HeLa), were analyzed the expression levels of mRNA and protein of SKP2 and p27 by RT-PCR and Western blot analysis, respectively. RESULTS The expression of SKP2, p27 and phospho-MAPK/ERK1/2 were strongly associated with cervical neoplastic progression (P<0.0001, P=0.006, P=0.003, respectively; Fisher's Exact Test). In addition, SKP2 expression was positively correlated with phospho-MAPK/ERK1/2 expression (Spearman correlation coefficient=0.480, P=0.0002). The association between SKP2 and phospho-MAPK/ERK1/2 was significant after controlling for the four histologic grades (P=0.038, Mantel-Haenszel test). CONCLUSIONS These results suggest that expression levels of SKP2, p27 and phospho-MAPK/ERK1/2 may serve as markers for progression in human cervical carcinoma and may also play roles in cervical carcinoma progression and cervical carcinogenesis.
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Affiliation(s)
- Tzu-Ping Chen
- Department of Pathology, E-DA Hospital, Kaohsiung, Taiwan
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Handra-Luca A, Ruhin B, Lesty C, Fouret P. P27, SKP2, and extra-cellular signal-related kinase signalling in human salivary gland mucoepidermoid carcinoma. Oral Oncol 2006; 42:1005-10. [PMID: 16757206 DOI: 10.1016/j.oraloncology.2005.12.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Accepted: 12/13/2005] [Indexed: 10/24/2022]
Abstract
Extra-cellular signal-related kinase (ERK) can modulate P27 in several ways. ERK is phosphorylated in a subset of salivary gland mucoepidermoid carcinoma (MEC). We determined immunohistochemical expression of P27, SKP2, cyclin A, Ki67, phospho-RB, and phospho-ERK in 43 MEC. SKP2 correlated with tumour size, microscopic grade, and a worse prognosis. Cyclin A and Ki67 also predicted prognosis, and were correlated with SKP2. P27 did not predict prognosis. P27 had no inverse relationship with SKP2, and correlated with neither Ki67 nor cyclin A. Instead, P27 high expressers had higher levels of phospho-ERK and phospho-RB. When highly expressed, P27 co-localized with cyclin D1 in the nuclei. Relationships of P27 with ERK and RB and its nuclear co-localization with cyclin D1 favour the hypothesis that P27 is in complexes with cyclin D1. This may explain why P27 in contrast to SKP2 and cyclin A does not correlate with tumour cell proliferation and prognosis.
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Affiliation(s)
- Adriana Handra-Luca
- Service d'Anatomie Pathologique, AP-HP Hôpital Jean Verdier and Université Paris 13/Nord, France
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Adamowicz M, Radlwimmer B, Rieker RJ, Mertens D, Schwarzbach M, Schraml P, Benner A, Lichter P, Mechtersheimer G, Joos S. Frequent amplifications and abundant expression of TRIO, NKD2, and IRX2 in soft tissue sarcomas. Genes Chromosomes Cancer 2006; 45:829-38. [PMID: 16752383 DOI: 10.1002/gcc.20343] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Copy number gains and high-level amplifications of the short arm of chromosome 5 are frequently observed in soft tissue sarcomas. To identify genes from this region possibly involved in tumor progression, we analyzed 34 soft tissue sarcomas (10 pleomorphic and 8 dedifferentiated liposarcomas, 6 malignant fibrous histiocytomas, and 10 malignant peripheral nerve sheath tumors (MPNST)) using a DNA microarray including 418 BAC clones representing 99% of chromosome arm 5p. In seven tumors, distinct high-level amplifications were identified affecting four different subregions. From these regions, genes TERT, TRIO, SKP2, FBXO32, NKD2, SLC6A3, IRX2, POLS, FYB, PTGER4, and FGF10 were selected for detailed quantitative expression analysis (RQ-PCR) based on their potential tumorigenic function. Of these, TRIO, coding for a guanidine nucleotide exchange factor, was consistently overexpressed in all cases, while IRX2 and NKD2, both involved in the regulation of developmental processes via the WNT pathway, showed a characteristic expression only in MPNSTs. Detailed nonparametric multidimensional scaling analysis further showed that the expression of TRIO, IRX2, and NKD2 strongly correlated with the gene copy number. In conclusion, we found TRIO, IRX2, and NKD2 frequently affected by high-level amplifications as well as up-regulated in a gene-dosage dependent manner. Thus, these genes represent candidate targets of 5p amplifications in soft tissue sarcomas and might play a crucial role during the progression of this disease.
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Affiliation(s)
- Martyna Adamowicz
- Division of Molecular Genetics (B060), German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany
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Abstract
The F-box-containing protein Skp2 plays a critical role in coordinating the G1/S transition and progression through the S phase of the mammalian cell cycle. Skp2 is overexpressed in a broad spectrum of human cancers and the expression level correlates with tumor malignancy. However, the Skp2 gene is neither amplified nor rearranged in most human cancers and the underlying mechanism of Skp2 overexpression remains poorly understood. We show here that the Skp2 gene contains a functional E2F response element (hSRE2). Ectopic expression of E2F1 induces expression of the endogenous Skp2 gene in human fibroblast cells, whereas antisense-mediated knockdown of E2F1 in human tumor cell lines reduces expression of endogenous Skp2 gene. The hSRE2 element not only participates in activation of Skp2 promoter function during normal cell cycle progression into S phase, it is also required for the high-level Skp2 gene expression in many human tumor cell lines. These results reveal Skp2 as a novel target for E2F regulation that is disrupted in several human tumor cell lines.
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Affiliation(s)
| | - C Wang
- Correspondence: Associate Professor C Wang, Center for Molecular Biology of Oral Diseases, University of Illinois at Chicago, 801 South Paulina Street, Room 530E, m/c 860, Chicago, IL 60612, USA. E-mail:
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Abstract
A driving force of the cell cycle is the activation of cyclin-dependent kinases (CDKs), the activities of which are controlled by the ubiquitin-mediated proteolysis of key regulators such as cyclins and CDK inhibitors. Two ubiquitin ligases, the SKP1-CUL1-F-box-protein (SCF) complex and the anaphase-promoting complex/cyclosome (APC/C), are responsible for the specific ubiquitylation of many of these regulators. Deregulation of the proteolytic system might result in uncontrolled proliferation, genomic instability and cancer. Cumulative clinical evidence shows alterations in the ubiquitylation of cell-cycle regulators in the aetiology of many human malignancies. A better understanding of the ubiquitylation machinery will provide new insights into the regulatory biology of cell-cycle transitions and the development of anti-cancer drugs.
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Affiliation(s)
- Keiichi I Nakayama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan.
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Huang HY, Kang HY, Li CF, Eng HL, Chou SC, Lin CN, Hsiung CY. Skp2 overexpression is highly representative of intrinsic biological aggressiveness and independently associated with poor prognosis in primary localized myxofibrosarcomas. Clin Cancer Res 2006; 12:487-498. [PMID: 16428491 DOI: 10.1158/1078-0432.ccr-05-1497] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Two SCF(Skp2) ubiquitin ligase-related proteins, Skp2 and cyclin-dependent kinase subunit 1 (Cks1), are involved in posttranscriptional degradation of p27(Kip1) tumor suppressor. We analyzed the prognostic utility of p27(Kip1) and its interacting cell cycle regulators in myxofibrosarcomas. EXPERIMENTAL DESIGN Clinicopathologic features and tissue microarray-based immunohistochemical expression of p27(Kip1), Skp2, Cks1, cyclin E, cyclin A, Ki-67, and minichromosome maintenance protein 2 (Mcm2) were assessed in 70 primary myxofibrosarcomas and correlated with clinical outcomes. Skp2 mRNA expression and the relationship between Skp2 and p27(Kip1) proteins were examined in six cases by semiquantitative reverse transcription-PCR and Western blotting, respectively. RESULTS High indices of Skp2 (> or =10%), cyclin A (> or =10%), and Mcm2 (> or =50%) were adverse prognosticators at the univariate level. Furthermore, co-overexpression of Skp2 and cyclin A identified highly lethal cases in the entire cohort [P < 0.0001 for disease-specific survival (DSS), P = 0.0004 for overall survival (OS)] and the lower-grade subset (Fédération Nationale des Centres de Lutte Contre le Cancer grade 1 and 2; P = 0.0006 for DSS, P = 0.0093 for OS). In multivariate analyses, Skp2 overexpression overshadowed most intrinsic clinicopathologic factors and independently correlated with worse metastasis-free survival (P = 0.0012), DSS (P = 0.0234), and OS (P = 0.0056). Notably, positive margins independently predicted inferior local recurrence-free survival (P = 0.0012) and also negatively affected metastasis-free survival (P = 0.0471), DSS (P = 0.0152), and OS (P = 0.0173). Reverse transcription-PCR showed up-regulation of Skp2 mRNA in four cases and Western blotting displayed a matched expression pattern of Skp2. CONCLUSIONS Margin status and intrinsic property of myxofibrosarcomas both affect patient survival. Skp2 overexpression is highly representative of the biological aggressiveness of myxofibrosarcomas and plays an important prognostic role.
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Affiliation(s)
- Hsuan-Ying Huang
- Departments of Pathology and Radiation Oncology and Graduate institute of Clinical Medical Science, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chang Gung University, 123 Ta-Pei Road, Niao-Sung, Kaohsiung County, Taiwan
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Yang ZL, Huang SF, Wang QW, Miao XY, Liang S. Expression and correlations of S-phase kinase associated protein 2 and P27 protein in pancreatic cancer tissues: an analyses of 51 cases. Shijie Huaren Xiaohua Zazhi 2005; 13:2717-2719. [DOI: 10.11569/wcjd.v13.i22.2717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To detect the expression of S-phase kinase associated protein 2 (SKP2) and P27 protein in human pancreatic ductal carcinoma and chronic pancreatitis, and to investigate the clinical significance and their correlations in the pancreatic ductal carcinoma.
METHODS: SP immunohistochemical method was used to detect the expression of SKP2 and P27 in the routinely paraffin-embedded sections of specimens from patients with pancreatic ductal carcinoma (n = 51) and chronic pancreatitis (n = 10)..
RESULTS: The positive rate of SKP2 expression in the pancreatic ductal carcinoma (28/51, 54.9%) was significantly higher than that in the chronic pancreatitis (2/10, 20.0%, P < 0.05), while the rate of P27 was significantly lower [25/51(49.0%) vs 9/10(90.0%), P < 0.05]. The positive rates of SKP2 expression was significantly lower in the well-differentiated (7/20, 35.0%) and non-metastasis cases (5/16, 31.2%) than those in the poorly-differentiated (14/19, 73.7%) and metastasis ones (23/35, 65.7%) (P < 0.05), while the rate of P27 expression was significantly higher in the well-differentiated (13/20, 65.0%) and non-metastasis cases (12/16, 75.0%) than those in the poorly-differentiated (6/19, 31.5%) and metastasis ones (13/35, 37.1%) (P < 0.05 or P < 0.01). The expression of SKP2 and P27 were closely correlated in the pancreatic ductal carcinoma tissue (χ2 = 14.33, P < 0.01)..
CONCLUSION: SKP2 and P27 are important biological markers for reflecting the carcinogenesis, progression, and prognosis of pancreatic ductal carcinoma. The positive expression of SKP2 or the negative expression of P27 reveals more serious status of the illness, the tendency of metastasis and unfavorable prognosis. There may be a co-regulatory relationship between SKP2 and P27 expression.
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Jiang F, Caraway NP, Li R, Katz RL. RNA silencing of S-phase kinase-interacting protein 2 inhibits proliferation and centrosome amplification in lung cancer cells. Oncogene 2005; 24:3409-18. [PMID: 15735730 DOI: 10.1038/sj.onc.1208459] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The S-phase kinase-associated protein-2 (SKP2) plays a key role in ubiquitin-mediated proteolysis, which results in the progression of cells from a quiescence to proliferative state. SKP2 is overexpressed in a variety of tumors. In this study, we used small interfering RNAs (siRNAs) to inhibit the SKP2 expression in lung cancer cells and thereby investigate the role of SKP2 in lung tumorigenesis. Three lung cancer cell lines were transfected with siRNAs targeted against SKP2. SKP2-siRNAs specifically and efficiently reduced the levels of the SKP2 protein by 90% 48 h after transfection in all cell lines. In the A549 and H1792 cells, p27 expression was increased and the increase was inversely proportional to the level of SKP2; cell proliferation was reduced to 12 and 28%, respectively; apoptosis was increased to 36 and 30%, respectively; 36 and 28% of cells accumulated in the sub-G1 phase, respectively; and the population of cells in the G1 phase was decreased to 37 and 41%, respectively. In addition, the SKP2-depleted A549 and H1792 cells showed decreased levels of cyclin E/CDK2. Correspondingly, only 4 and 6% of the treated A549 and H1792 cells had multiple centrosomes, respectively, compared with 43 and 46% of the control cells, respectively. These results imply that SKP2 plays an oncogenic role in lung cancer and that SKP2 silencing may be useful in the treatment of lung cancer.
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Affiliation(s)
- Feng Jiang
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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Langner C, von Wasielewski R, Ratschek M, Rehak P, Zigeuner R. Expression of p27 and its ubiquitin ligase subunit Skp2 in upper urinary tract transitional cell carcinoma. Urology 2005; 64:611-6. [PMID: 15351619 DOI: 10.1016/j.urology.2004.04.072] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2004] [Accepted: 04/30/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVES To analyze p27 and S-phase kinase-associated protein 2 (Skp2) expression in upper urinary tract transitional cell carcinoma (TCC) with respect to biologic significance. p27 (p27/kip1) is involved in cell cycle control, and loss of p27 protein expression may result in tumor development and/or progression. The association of p27 with the ubiquitin ligase subunit Skp2 targets p27 for degradation. METHODS A total of 53 upper urinary tract TCC specimens were investigated immunohistochemically using a tissue microarray technique. The immunoreactivity of p27 and Skp2 was analyzed with respect to associations with pT stage, grade, and prognosis. RESULTS Non-neoplastic renal tissue showed p27 immunoreactivity in tubule epithelium and pelvic urothelium, but lacked immunoreactivity for Skp2. In the TCC specimens, p27 immunoreactivity was noted in 47 (89%) of 53 cases. High p27 expression (50% or greater of tumor cell nuclei) tended to decrease with rising tumor stage (14 [45%] of 31 with pT1-pT2 versus 4 [18%] of 22 with pT3; P = 0.076), but was independent of tumor grade (11 [39%] of 28 grade 2 versus 7 [28%] of 25 grade 3-4; P = 0.56). Skp2 immunoreactivity was noted in 32 (60%) of 53 tumors. Skp2 expression increased with rising tumor stage (9 [41%] of 22 pT1 versus 23 [74%] of 31 pT2-pT3; P = 0.023) and tumor grade (12 [43%] of 28 grade 2 versus 20 [80%] of 25 grade 3; P = 0.043) and was associated with angioinvasion (P = 0.017). In multivariate analysis, tumor stage proved to be the only independent prognostic factor regarding disease-free survival. CONCLUSIONS p27 and Skp2 are additional biomarkers in urogenital pathologic findings. The statistically significant association of Skp2 expression with high-grade TCC, as well as the lack of expression in non-neoplastic tissue, suggests that Skp2 could be a promising target for future cancer therapy strategies.
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Affiliation(s)
- Cord Langner
- Institute of Pathology, University of Graz Medical School, Graz, Austria
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Li Q, Murphy M, Ross J, Sheehan C, Carlson JA. Skp2 and p27kip1 expression in melanocytic nevi and melanoma: an inverse relationship. J Cutan Pathol 2005; 31:633-42. [PMID: 15491322 DOI: 10.1111/j.0303-6987.2004.00243.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND S-phase kinase associated protein-2 (Skp2) ubiquitin ligase p45(SKP2) is important in the degradation of p27kip1 (a cyclin dependent kinase inhibitor) and progression through the G1-S cell-cycle checkpoint. Low levels of p27 and high levels of Skp2 are related to poor prognosis in some cancers. METHODS Clinicopathologic features and immunohistochemical expression of Skp2 and p27kip1 were investigated in 198 melanocytic proliferations: 21 melanocytic nevi, 23 melanoma in situ, 119 primary melanoma, and 35 metastatic melanoma samples. Comparative and survival analyses were performed. RESULTS Progressive and significant increases and decreases in the nuclear expression of Skp2 and p27kip1, respectively, was identified moving from melanocytic nevi (0.05 +/- 0.2/85 +/- 15) to melanoma in situ (3 +/- 2/45 +/- 20) to primary cutaneous melanoma (12 +/- 9/30 +/- 25) to metastatic melanoma (25 +/- 15/15 +/- 20) (p < or = 0.006). Expression of these proteins also significantly correlated with increasing American Joint Committee on Cancer (AJCC) T (tumor) classification and AJCC stage (p < or = 0.01). Moreover, the level of these two proteins exhibited a significant inverse relationship (r = -0.4, p = 0.0001). Skp2 cytoplasmic labeling index of >20% predicted worse 10-year overall survival (38% vs. 86%, p = 0.04) in primary melanoma. Neither p27 nor Skp2 nuclear expression impacted significantly on prognosis. CONCLUSIONS Gain of Skp2 and loss of p27kip1 protein expression are implicated in melanoma progression where the level of p27kip1 may be regulated by targeted proteolysis via Skp2. Cytoplasmic expression of Skp2 defines a subset of aggressive melanomas and could represent another pathway of deregulation of the cell cycle.
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Affiliation(s)
- Qing Li
- Department of Pathology and Laboratory Medicine, Albany Medical College, New Scotland Ave., Albany, NY 12208, USA
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Zhu CQ, Blackhall FH, Pintilie M, Iyengar P, Liu N, Ho J, Chomiak T, Lau D, Winton T, Shepherd FA, Tsao MS. Skp2 gene copy number aberrations are common in non-small cell lung carcinoma, and its overexpression in tumors with ras mutation is a poor prognostic marker. Clin Cancer Res 2004; 10:1984-91. [PMID: 15041716 DOI: 10.1158/1078-0432.ccr-03-0470] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Skp2 plays a critical role in cell cycle progression, especially at the G(1)-S transition, putatively through its control of several cell cycle regulator proteins. The Skp2 gene is located on a region of chromosome 5p that is commonly overrepresented in lung cancer. The present study aimed to evaluate Skp2 abnormalities and their prognostic value in non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN In total 16 NSCLC cell lines and 163 primary tumors were included in studies to measure Skp2 relative gene copy number, mRNA abundance, and protein level. The tumors were also evaluated for p27 protein expression level and ras mutation. These values were correlated with the clinical and pathological features of the patients. RESULTS Skp2 relative gene copy number aberrations were found in 88 and 65% of NSCLC cell lines and primary tumors, respectively. Overrepresentation was especially common among squamous cell carcinoma (74%). Both gene copy overrepresentation (13%) and loss (35%) were found in adenocarcinoma. Skp2 relative gene copy number was significantly correlated with mRNA and protein levels, but none of these were correlated with p27 protein levels. Neither high Skp2 protein expression nor ras mutation was prognostically significant. In NSCLCs with ras mutation, however, high Skp2 protein expression was a significant independent poor prognostic marker. CONCLUSION There appears to be a synergistic interaction between high Skp2 protein expression and ras mutation with negative impact on the survival of NSCLC patients.
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Affiliation(s)
- Chang Qi Zhu
- University Health Network, Ontario Cancer Institute and Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada
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Sanada T, Yokoi S, Arii S, Yasui K, Imoto I, Inazawa J. Skp2 overexpression is a p27Kip1-independent predictor of poor prognosis in patients with biliary tract cancers. Cancer Sci 2004; 95:969-76. [PMID: 15596046 PMCID: PMC11158159 DOI: 10.1111/j.1349-7006.2004.tb03185.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Revised: 10/21/2004] [Accepted: 10/23/2004] [Indexed: 12/30/2022] Open
Abstract
To better understand the pathogenesis of biliary tract carcinoma (BTC) and to increase the accuracy of predicting outcomes for patients with this disease, we performed molecular cytogenetic analyses of BTC cell lines and tumors to identify non-random amplification(s) and target gene(s) within the amplicons. Among several non random chromosomal aberrations detected in BTC cell lines by comparative genomic hybridization, gain/ampli-fication of DNA at 5p was the most frequently observed alteration. We assessed the copy number and expression status of the possible target gene SKP2 for 5p amplification in cell lines and 33 primary stage II or III tumors of BTC. SKP2 was amplified, and subsequently overexpressed in both cell lines and primary tumors of BTC. However, levels of Skp2 and p27Kip1 proteins were not correlated inversely. Heightened expression of Skp2 and reduced expression of p27Kip1 were both associated with a shorter disease-free and/or overall survival in univariate analyses. In multivariate regression analyses, Skp2 and p27Kip1 were independent predictive factors. Those results suggest that (a) overexpression of Skp2 through an amplification mechanism may contribute to the progression of BTC, (b) not only each molecule, but also the combination of Skp2 and p27Kip1, might be a useful predictor of the prognosis of BTC, and (c) molecular targets of Skp2 other than p27Kip1 may also be important factors in the pathogenesis of this disease.
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Affiliation(s)
- Takahiro Sanada
- Department of Molecular Cytogenetics, School of Biomedical Science, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
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Langner C, von Wasielewski R, Ratschek M, Rehak P, Zigeuner R. Biological significance of p27 and Skp2 expression in renal cell carcinoma. A systematic analysis of primary and metastatic tumour tissues using a tissue microarray technique. Virchows Arch 2004; 445:631-6. [PMID: 15517366 DOI: 10.1007/s00428-004-1121-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Accepted: 08/18/2004] [Indexed: 02/01/2023]
Abstract
p27 (p27/kip1) is involved in cell-cycle control, and loss of p27 expression may result in tumour development and/or progression. Association with Skp2 targets p27 for degradation. Using a tissue microarray technique, 171 primary renal cell carcinomas (RCCs) and 58 RCC metastases were immunostained for p27 and Skp2. p27 Immunoreactivity was noted in 83 of 129 (64%) clear cell, 6 of 22 (27%) chromophobe and 15 of 20 (75%) papillary tumours as well as 44 of 58 (76%) metastases. In clear cell cancers, high p27 expression (> or =50% of tumour cells) decreased with rising tumour stage (50% pT1/pT2 versus 20% pT3; P<0.001) and grade (44% G1/G2 versus 21% G3/G4; P=0.008). None of 22 chromophobe cancers showed high expression in contrast to 46 of 129 (36%) clear cell tumours (P<0.001). Skp2 expression was noted in 8 of 129 (6%) clear cell cancers and 11 of 55 (20%) metastases (P=0.008). Immunoreactivity increased with rising tumour stage (1% pT1/pT2 versus 11% pT3; P=0.03) and grade (1% G1/G2 versus 15% G3/G4; P=0.004) and was associated with sarcomatoid morphology (P<0.001). In multivariate analysis, patients with low p27 expression and Skp2 immunoreactivity in clear cell cancers had a less favourable outcome. In conclusion, p27 and Skp2 proved to be additional biomarkers in renal cancer pathology with both prognostic and diagnostic impact.
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Affiliation(s)
- Cord Langner
- Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036 Graz, Austria.
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Yokoi S, Yasui K, Mori M, Iizasa T, Fujisawa T, Inazawa J. Amplification and overexpression of SKP2 are associated with metastasis of non-small-cell lung cancers to lymph nodes. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 165:175-80. [PMID: 15215173 PMCID: PMC1618537 DOI: 10.1016/s0002-9440(10)63286-5] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
SKP2, an F-box protein constituting the substrate recognition subunit of the SCF(SKP2) ubiquitin ligase complex, is implicated in ubiquitin-mediated degradation of the cyclin-dependent kinase inhibitor p27(KIP1). Our earlier studies revealed SKP2 as a target gene within the 5p13 amplicon that is often seen in small-cell lung cancers. In the present study we examined amplification status and expression levels of SKP2 in non-small-cell lung cancer (NSCLC) and investigated its clinicopathological significance in this type of tumor because amplification of DNA at 5p13 is observed frequently in NSCLCs as well as in small-cell lung cancers. SKP2 exhibited amplification in 5 (20%) of 25 cell lines derived from NSCLC, and the transcript was overexpressed in 11 (44%) of the 25 lines. Moreover, expression of SKP2 was up-regulated significantly in 60 primary NSCLC tumors as compared to nontumorous lung tissues (P < 0.0001). Elevated expression of SKP2 correlated significantly with positive lymph node metastasis (P = 0.007), with stage II or higher of the international TNM classification (P = 0.014), with poor or moderate differentiation (P < 0.001), and with the presence of squamous cell carcinoma (P = 0.037). Reduction of SKP2 expression by transfection of an anti-sense oligonucleotide inhibited invasion and migration of NSCLC cells in culture. Our results suggest that SKP2 may be involved in progression of NSCLC, and that targeting this molecule could represent a promising therapeutic option.
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Affiliation(s)
- Sana Yokoi
- Department of Molecular Cytogenetics, Graduate School of Biomedical Science, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
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Min YH, Cheong JW, Lee MH, Kim JY, Lee ST, Hahn JS, Ko YW. Elevated S-Phase Kinase-Associated Protein 2 Protein Expression in Acute Myelogenous Leukemia. Clin Cancer Res 2004; 10:5123-30. [PMID: 15297415 DOI: 10.1158/1078-0432.ccr-04-0136] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The F-box protein S-phase kinase-associated protein 2 (Skp2) positively regulates the G(1)-S phase transition by controlling the stability of several G(1) regulators, such as p27Kip1. However, the clinical significance of Skp2 in patients with acute myelogenous leukemia (AML) remains unknown. EXPERIMENTAL DESIGN We examined the clinical and biological significance of Skp2 expression in AML and evaluated the relationship between Skp2 and p27Kip1 expression and phosphatase and tensin homologue (PTEN) phosphorylation. RESULTS Western blot analysis showed that high Skp2 expression was observed in 57 (57.6%) cases and significantly correlated with unfavorable cytogenetics (P = 0.035) but not with age, white blood cell count, serum lactic dehydrogenase level, and the French-American-British subtype. An inverse correlation was not observed between Skp2 and p27Kip1 expression. However, p27Kip1 protein was preferentially localized to cytoplasm in the high-Skp2-expression group. The cytoplasmic to nuclear ratio of p27Kip1 expression was significantly correlated with the levels of Skp2 expression (P < 0.001). The frequency of PTEN phosphorylation was significantly higher in the high-Skp2-expression group compared with the low- Skp2-expression group (P = 0.035). The Skp2 overexpression was significantly associated with shorter disease-free survival and overall survival (P = 0.0386 and P = 0.0369, respectively). Multivariate analysis showed that Skp2 expression was an independent prognostic factor both in the disease-free survival and overall survival. CONCLUSION These findings suggest that Skp2 expression is an independent marker for a poor prognosis in AML. The presence of a positive correlation between Skp2 and phosphorylated PTEN suggests that an aberration in the PTEN/Skp2 signaling pathway might be operating in AML.
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Affiliation(s)
- Yoo Hong Min
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
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Abstract
Understanding prognostic variables is important for counseling patients, selecting patients for adjuvant therapy, stratifying patients for inclusion in clinical trials, and setting goals for patient treatment. Prognostic variables in soft tissue sarcoma have been defined for local recurrence, distant recurrence, and disease-specific and overall survival. Significant prognostic variables are site-dependent and time-dependent. A recently created nomogram that accounts for tumor size, grade, histology, and depth and patient age is a tool that can be used to predict 12-year sarcoma-specific survival at diagnosis. Emerging areas in predicting outcome of patients with soft tissue sarcoma include response to neoadjuvant chemotherapy and molecular markers.
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Affiliation(s)
- Stephen R Grobmyer
- Department of Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA
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