Original Article
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World J Gastroenterol. May 14, 2013; 19(18): 2772-2780
Published online May 14, 2013. doi: 10.3748/wjg.v19.i18.2772
Oncogene GAEC1 regulates CAPN10 expression which predicts survival in esophageal squamous cell carcinoma
Dessy Chan, Miriam Yuen-Tung Tsoi, Christina Di Liu, Sau-Hing Chan, Simon Ying-Kit Law, Kwok-Wah Chan, Yuen-Piu Chan, Vinod Gopalan, Alfred King-Yin Lam, Johnny Cheuk-On Tang
Dessy Chan, Miriam Yuen-Tung Tsoi, Christina Di Liu, Sau-Hing Chan, Johnny Cheuk-On Tang, State Key Laboratory of Chirosciences, Lo Ka Chung Centre for Natural Anti-cancer Drug Development, Department of Applied Biology and Chemical Technology, the Hong Kong Polytechnic University, Hong Kong, China
Simon Ying-Kit Law, Department of Surgery, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
Kwok-Wah Chan, Yuen-Piu Chan, Department of Pathology, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
Vinod Gopalan, Alfred King-Yin Lam, Department of Pathology, Griffith Medical School and Griffith Health Institute, Griffith University, Gold Coast, Queensland 4222, Australia
Author contributions: Chan D, Tsoi MYT, Liu CD and Chan SH contributed research design and technical support; Law SYK contributed data collection; Chan KW and Chan YP contributed analytic tools; Gopalan V and Lam AKY analyzed data; Chan D and Tang JCO contributed research design and wrote the paper.
Supported by The General Research Fund, offered by Research Grant Council of Hong Kong to Tang JCO and Lam AKY, PolyU 5627/08M; Griffith Health Institute Project Grant
Correspondence to: Dr. Johnny Cheuk-On Tang, PhD, State Key Laboratory of Chirosciences, Lo Ka Chung Centre for Natural Anti-cancer Drug Development, Department of Applied Biology and Chemical Technology, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China. bccotang@polyu.edu.hk
Telephone: +86-852-34008727 Fax: +86-852-30138935
Received: September 7, 2012
Revised: November 3, 2012
Accepted: February 5, 2013
Published online: May 14, 2013
Abstract

AIM: To identify the downstream regulated genes of GAEC1 oncogene in esophageal squamous cell carcinoma and their clinicopathological significance.

METHODS: The anti-proliferative effect of knocking down the expression of GAEC1 oncogene was studied by using the RNA interference (RNAi) approach through transfecting the GAEC1-overexpressed esophageal carcinoma cell line KYSE150 with the pSilencer vector cloned with a GAEC1-targeted sequence, followed by MTS cell proliferation assay and cell cycle analysis using flow cytometry. RNA was then extracted from the parental, pSilencer-GAEC1-targeted sequence transfected and pSilencer negative control vector transfected KYSE150 cells for further analysis of different patterns in gene expression. Genes differentially expressed with suppressed GAEC1 expression were then determined using Human Genome U133 Plus 2.0 cDNA microarray analysis by comparing with the parental cells and normalized with the pSilencer negative control vector transfected cells. The most prominently regulated genes were then studied by immunohistochemical staining using tissue microarrays to determine their clinicopathological correlations in esophageal squamous cell carcinoma by statistical analyses.

RESULTS: The RNAi approach of knocking down gene expression showed the effective suppression of GAEC1 expression in esophageal squamous cell carcinoma cell line KYSE150 that resulted in the inhibition of cell proliferation and increase of apoptotic population. cDNA microarray analysis for identifying differentially expressed genes detected the greatest levels of downregulation of calpain 10 (CAPN10) and upregulation of trinucleotide repeat containing 6C (TNRC6C) transcripts when GAEC1 expression was suppressed. At the tissue level, the high level expression of calpain 10 protein was significantly associated with longer patient survival (month) of esophageal squamous cell carcinoma compared to the patients with low level of calpain 10 expression (37.73 ± 16.33 vs 12.62 ± 12.44, P = 0.032). No significant correction was observed among the TNRC6C protein expression level and the clinocopathologcial features of esophageal squamous cell carcinoma.

CONCLUSION: GAEC1 regulates the expression of CAPN10 and TNRC6C downstream. Calpain 10 expression is a potential prognostic marker in patients with esophageal squamous cell carcinoma.

Keywords: Esophageal squamous cell carcinoma, Oncogene, RNA interference, Calpain 10, Tissue microarray