The role of RhoC in the proliferation and apoptosis of hepatocellular carcinoma cells.
ABSTRACT In this study, we examined the effects of RhoC expression on the growth and apoptosis of human hepatocellular carcinoma cells (HCCs) in vitro in order to gain more understanding of its potential as a therapeutic target gene. We knocked down the endogenous expression levels of RhoC in human HCCs, BEL-7402, using siRNA and ectopically expressed RhoC in untransformed hepatocytes, HL7702. Stable cell lines were established, and cell growth was examined by MTT and colony formation assays, cell proliferation examined by silver nitrate staining of AgNORs, and cell cycle distribution examined by flow cytometry. RT-PCR analysis was performed to determine the mRNA expression levels of RhoC and cell cycle-related genes. Finally, the effect of RhoC expression on apoptosis was also examined by flow cytometry, agarose gel electrophoresis of fragmented DNA, Wright staining, and RT-PCR analysis for genes regulating apoptosis. Compared to the parental and control siRNA (siCtrl)-transfected BEL-7402 cells, the siRhoC-transfected cells exhibited significantly reduced cell growth, cell proliferation, percentage of cells in the S-G2/M phase, and expression of Cyclin D1, CDK4, and Bcl2. Knockdown of RhoC expression in BEL-7402 cells also significantly increased the percentage of cells in the G0/G1 phase, cellular apoptosis, and expression of p21, p16, and Bax. Furthermore, ectopic expression of RhoC in HL7702 cells led to a significant increase in cell growth compared to parental or siCtrl-transfected cells. These data suggest that RhoC is a key regulator of cell growth and apoptosis in HCC cells, making it a potential target for gene therapy.
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ABSTRACT: To investigate the expression of RhoC gene in hepatocellular carcinoma (HCC) and to evaluate the relationship between RhoC gene expression and invasion and metastasis of HCC. mRNA expression level of RhoC gene was examined by reverse transcription-polymerase chain reaction (RT-PCR) in 25 cases of HCC and para-cancerous normal liver tissues. In addition, mutation of RhoC gene was examined by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP). The mRNA expression levels of RhoC in tumor tissues were significantly higher than those in para-cancerous normal liver tissues (1.8+/-1.1 vs 1.0+/-0.7, P<0.01). The metastatic lesions outside of liver also showed significantly higher RhoC mRNA levels than corresponding tumor tissues in liver (3.3+/-0.5 vs 2.0+/-0.7, P<0.01). There were significant associations between RhoC gene expression and certain clinical and pathological findings, including cell differentiation, vein invasion, number of tumor nodes and metastatic lesions. Mutation of RhoC gene was not found by PCR-SSCP. The RhoC gene may be related to malignant transformation and development of HCC and may play an important role in the invasion and metastasis of HCC by overexpression but not mutation.World Journal of Gastroenterology 10/2003; 9(9):1950-3. · 2.55 Impact Factor
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ABSTRACT: Nasopharyngeal carcinoma (NPC) is a rare malignancy in most part of the world and it is one of the most confusing, commonly misdiagnosed and poorly understood diseases. The cancer is an Epstein-Barr virus-associated malignancy with a remarkable racial and geographical distribution. It is highly prevalent in southern Asia where the disease occurs at a prevalence about a 100-fold higher compared with other populations not at risk. The etiology of NPC is thought to be associated with a complex interaction of genetic, viral, environmental and dietary factors. Thanks to the advancements in genomics, proteomics and bioinformatics in recent decades, more understanding of the disease etiology, carcinogenesis and progression has been gained. Research into these components may unravel the pathways in NPC development and potentially decipher the molecular characteristics of the malignancy. In the era of molecular medicine, specific treatment to the potential target using technologies such as immunotherapy and RNAi becomes formulating from bench to bedside application and thus makes molecular biomarker discovery more meaningful for NPC management. In this article, the latest molecular biomarker discovery and progress in NPC is reviewed with respect to the diagnosis, monitoring, treatment and prognostication of the disease.Molecular Cancer 02/2007; 6:1. · 5.13 Impact Factor
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ABSTRACT: The angiogenesis induced by tumor cells is essential for metastasis of hepatocellular carcinoma. Available information suggests that RhoC participates in angiogenesis through regulation of vascular endothelial growth factor expression in tumor cells. For its broad functions in cell migration and cytoskeletal organization, we hypothesized that RhoC regulating angiogenesis does not exclusively depend on regulation of vascular endothelial growth factor expression. To address this question, in the present study, we used a retroviral small interfering RNA approach to selectively knockdown the expression of RhoC in a neovascularization model in vivo and in vitro. Our present results indicate that RhoC is the downstream regulator of vascular endothelial growth factor in endothelial cells and is essential for angiogenesis induced by vascular endothelial growth factor, notwithstanding that RhoC regulates the expression of vascular endothelial growth factor in tumor cells. Furthermore, we show that knockdown of RhoC is associated with the inhibition of invasion and migration but not apoptosis of endothelial cells. Knockdown of RhoC results in inhibition of endothelial cell organization through restraining the reorganization of F-actin filaments, which represses endothelial cell network and sprout formation. In conclusion, our results demonstrate that knockdown of RhoC inhibits angiogenesis induced by tumor cells not only through effecting the release of vascular endothelial growth factor, but also through inhibiting endothelial cell migration and organization, which implies that it blocks tumor metastasis by specifically inhibiting RhoC in endothelial cells.Cancer Science 11/2008; 99(10):2012-8. · 3.48 Impact Factor