Original Article
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Aug 14, 2012; 18(30): 3962-3976
Published online Aug 14, 2012. doi: 10.3748/wjg.v18.i30.3962
Increased expression of chondroitin sulphate proteoglycans in rat hepatocellular carcinoma tissues
Xiao-Li Jia, Si-Yuan Li, Shuang-Suo Dang, Yan-An Cheng, Xin Zhang, Wen-Jun Wang, Clare E Hughes, Bruce Caterson
Xiao-Li Jia, Shuang-Suo Dang, Yan-An Cheng, Xin Zhang, Wen-Jun Wang, Department of Infectious Diseases, The Second Affiliated Hospital of Medical School of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China
Si-Yuan Li, Clare E Hughes, Bruce Caterson, Connective Tissue Biology Laboratories, Division of Pathophysiology and Repair, School of Biosciences, Cardiff University, Cardiff, Wales CF10 3AX, United Kingdom
Si-Yuan Li, The Institute of Endemic Disease, Medical School of Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
Author contributions: Jia XL, Dang SS and Cheng YA designed the research; Jia XL, Li SY, Zhang X and Wang WJ performed the experiments; Li SY and Hughes CE provided the reagents; Jia XL, Li SY, Hughes CE and Caterson B analyzed the data; Jia XL, Dang SS, Li SY, Hughes CE and Caterson B wrote the manuscript.
Supported by The National Natural Science Foundation of China, No. 30471982 (to Dang SS and Cheng YA); and Arthritis Research UK, No. 18331 (to Hughes CE and Caterson B)
Correspondence to: Shuang-Suo Dang, MD, PhD, Department of Infectious Disease, The Second Affiliated Hospital of Xi’an Jiaotong University, 157 Xiwu Road, Xi’an 710004, Shaanxi Province, China. dang212@126.com
Telephone: +86-29-87679688 Fax: +86-29-87678599
Received: February 13, 2012
Revised: March 28, 2012
Accepted: April 13, 2012
Published online: August 14, 2012

AIM: To investigate the expression of chondroitin sulphate proteoglycans (CSPGs) in rat liver tissues of hepatocellular carcinoma (HCC).

METHODS: Thirty male Sprague Dawley rats were randomly divided into two groups: control group (n = 10) and HCC model group (n = 20). Rats in the HCC model groups were intragastrically administrated with 0.2% (w/v) N-diethylnitrosamine (DEN) every 5 d for 16 wk, whereas 0.9% (w/v) normal saline was administered to rats in the control group. After 16 wk from the initiation of experiment, all rats were killed and livers were collected and fixed in 4% (w/v) paraformaldehyde. All tissues were embedded in paraffin and sectioned. Histological staining (hematoxylin and eosin and Toluidine blue) was performed to demonstrate the onset of HCC and the content of sulphated glycosaminoglycan (sGAG). Immunohistochemical staining was performed to investigate the expression of chondroitin sulphate (CS)/dermatan sulphate (DS)-GAG, heparan sulphate (HS)-GAG, keratan sulphate (KS)-GAG in liver tissues. Furthermore, expression and distribution of CSPG family members, including aggrecan, versican, biglycan and decorin in liver tissues, were also immunohistochemically determined.

RESULTS: After 16 wk administration of DEN, malignant nodules were observed on the surface of livers from the HCC model group, and their hepatic lobule structures appeared largely disrupted under microscope. Toluidine blue staining demonstrated that there was an significant increase in sGAG content in HCC tissues when compared with that in the normal liver tissues from the control group [0.37 ± 0.05 integrated optical density per stained area (IOD/area) and 0.21 ± 0.01 IOD/area, P < 0.05]. Immunohistochemical studies demonstrated that this increased sGAG in HCC tissues was induced by an elevated expression of CS/DS (0.28 ± 0.02 IOD/area and 0.18 ± 0.02 IOD/area, P < 0.05) and HS (0.30 ± 0.03 IOD/area and 0.17 ± 0.02 IOD/area, P < 0.01) but not KS GAGs in HCC tissues. Further studies thereby were performed to investigate the expression and distribution of several CSPG components in HCC tissues, including aggrecan, versican, biglycan and decorin. Interestingly, there was a distinct distribution pattern for these CSPG components between HCC tissues and the normal tissues. Positive staining of aggrecan, biglycan and decorin was localized in hepatic membrane and/or pericellular matrix in normal liver tissues; however, their expression was mainly observed in the cytoplasm, cell membranes in hepatoma cells and/or pericellular matrix within HCC tissues. Semi-quantitative analysis indicated that there was a higher level of expression of aggrecan (0.43 ± 0.01 and 0.35 ± 0.03, P < 0.05), biglycan (0.32 ± 0.01 and 0.25 ± 0.01, P < 0.001) and decorin (0.29 ± 0.01 and 0.26 ± 0.01, P < 0.05) in HCC tissues compared with that in the normal liver tissues. Very weak versican positive staining was observed in hepatocytes near central vein in normal liver tissues; however there was an intensive versican distribution in fibrosis septa between the hepatoma nodules. Semi-quantitative analysis indicated that the positive rate of versican in hepatoma tissues from the HCC model group was much higher than that in the control group (33.61% and 21.28%, P < 0.05). There was no positive staining in lumican and keratocan, two major KSPGs, in either normal or HCC liver tissues.

CONCLUSION: CSPGs play important roles in the onset and progression of HCC, and may provide potential therapeutic targets and clinical biomarkers for this prevalent tumor in humans.

Keywords: Hepatocellular carcinoma, Proteoglycan, Chondroitin sulphate, Heparan sulphate, Keratan sulphate