Original Article
Copyright copy;2010 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Sep 28, 2010; 16(36): 4541-4548
Published online Sep 28, 2010. doi: 10.3748/wjg.v16.i36.4541
Lowered HGK expression inhibits cell invasion and adhesion in hepatocellular carcinoma cell line HepG2
Su-Xia Han, Qing Zhu, Jin-Lu Ma, Jing Zhao, Chen Huang, Xi Jia, Dan Zhang
Su-Xia Han, Qing Zhu, Jin-Lu Ma, Jing Zhao, Xi Jia, Dan Zhang, Oncology Center of the First Affiliated Hospital, College of Medicine, Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
Chen Huang, Central Laboratory, College of Medicine, Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
Author contributions: Han SX and Zhu Q designed the research; Zhu Q, Ma JL, Zhao J, Jia X and Zhang D performed the research; Han SX, Zhu Q and Huang C provided new reagents/analytic tools; Ma JL and Zhao J analyzed the data; Han SX, Ma JL and Zhao J wrote the paper.
Supported by The Natural Science Foundation of China, No. 81071692
Correspondence to: Su-Xia Han, MD, PhD, Oncology Center of the First Affiliated Hospital, College of Medicine, Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China. hsummer22099@yahoo.cn
Telephone: +86-29-85323472 Fax: +86-29-85323473
Received: May 28, 2010
Revised: July 12, 2010
Accepted: July 19, 2010
Published online: September 28, 2010
Abstract

AIM: To investigate the effects of RNA interference targeting hepatocyte progenitor kinase-like kinase (HGK) in the invasion and adhesion of hepatocellular carcinoma (HCC) cell line HepG2.

METHODS: Three paired insert DNA fragments specific to HGK gene and one negative control DNA fragment were synthesized and inserted into RNAi-Ready pSIREN-RetroQ-ZsGreen vector. Western blotting assay and real-time reverse transcriptase polymerase chain reaction (RT-PCR) were used to screen the vector with a highest inhibitory rate. The vector was used to generate recombinant retrovirus specific to HGK. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2h-tetrazolium bromide (MTT) assay was used to examine cell growth; wound closure assay and cell adhesion assay were employed to investigate cell migration and adhesion respectively; and transwell assay and three-dimensional culture invasion assay were used to detect cell invasion. The expressions of matrix metalloproteinase (MMP)-2, MMP-9 and nuclear factor (NF)-κB were detected by Western blotting assay.

RESULTS: The real time RT-PCR and Western blotting assay showed that cells transfected with retrovirus mediating RNAi targeting of HGK (RV-shHGK)-1 vector had the strongest inhibition of HGK protein, with an inhibition rate of 76%, and this vector was used to generate recombinant retrovirus RV-shHGK-1. Cell adhesion assay and MTT assay found that cell adhesion and growth of the cells infected with RV-shHGK-1 were significantly lower than those of the control cells (P < 0.05). Wound closure assay, transwell assay and three-dimensional culture invasion assay showed that the cell invasiveness was significantly less in HGK knockdown cells than in the control cells (P < 0.05). The expressions of MMP-2, MMP-9 and NF-κB were inhibited in HepG2 cells infected with RV-shHGK-1.

CONCLUSION: Down-regulation of HGK can obviously inhibit the migration and invasion of HepG2 cells in vitro. HGK may be a new therapeutic target for treatment of HCC.

Keywords: Hepatocellular carcinoma, Hepatocyte progenitor kinase-like kinase, RNA interference, Invasion, Metastasis