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RHOC

BACKGROUND: RhoC is a small G protein/GTPase and involved in tumor mobility, invasion and metastasis. Previously, up-regulated RhoC expression is found to play an important role in ovarian carcinogenesis and subsequent progression by modulating proliferation, apoptosis, migration and invasion. METHODS: We transfected RhoC-expressing plasmid and RhoC siRNA into CAOV3 and OVCAR3 cells respectively. These cells and transfectants were exposed to vascular epithelial growth factor (VEGF), transforming growth factor (TGF)-beta1 or their receptor inhibitors with the phenotypes and their related-molecules examined. RESULTS: TGF-beta1R or VEGFR inhibitor suppressed the proliferation, migration, invasion and lamellipodia formation, the expression of N-cadherin, alpha-SMA, snail and Notch1 mRNA or protein, and enhanced E-cadherin mRNA and protein expression in CAOV3 and its RhoC-overexpressing transfectants, whereas both growth factors had the opposite effects in OVCAR3 cells and their RhoC-hypoexpressing transfectants. Ectopic RhoC expression enhanced migration, invasion, lamellipodia formation and the alteration in epithelial to mesenchymal transition (EMT) markers of CAOV3 cells regardless of the treatment of VEGFR or TGF-beta1R inhibitor, whereas RhoC knockdown resulted in the converse in OVCAR3 cells even with the exposure to VEGF or TGF-beta1. CONCLUSION: RhoC expression might be involved in EMT of ovarian epithelial carcinoma cells, stimulated by TGF-beta1 and VEGF.

Therapy-resistant cancer cells are a major problem in cancer research. Recent studies suggest that the epithelial-mesenchymal transition (EMT) is a key mechanism in therapy resistance. Yet, the expressions of EMT markers, EMT core regulators, and a stem cell marker of BMI1 during chemotherapy have been poorly analyzed in clinical breast cancer specimens. In the present study, we investigated the roles of RhoC under chemotherapy to follow up on earlier findings demonstrating the involvement of RhoC in prostate cancer resistance to endocrine therapy. Immunohistochemically, E-cadherin expression was significantly lower in human breast cancer specimens analyzed after chemotherapy than specimens biopsied before chemotherapy. Significant upregulation of fibronectin, a mesenchymal EMT marker, was found in post-chemotherapy analysis. A study of the EMT core regulators of SNAIL1, SNAIL2, TWIST1, and a well-known stem cell marker of BMI1 revealed no post-chemotherapy upregulation of these molecules. In contrast, RhoC expression was significantly upregulated in post-chemotherapy breast cancer specimens. MCF-7 cells stably transfected with the constitutive active (CA) RhoC plasmid manifested a reduced level of E-cadherin at the peripheries and disorganization of actin fibers, with no accompanying upregulation of SNAIL1, SNAIL2, TWIST1, or BMI1 in Western blots. Exposure of etoposide on MCF-7 cells showed RhoC upregulation together with reduced membranous expression of E-cadherin and disorganization of actin fibers. In MTT assay, however, the CA-RhoC-expressing MCF-7 cells failed to show chemotherapy resistance under etoposide treatment. Taken in sum, RhoC may contribute to an EMT-like process in human breast cancer during chemotherapy.

Ras homolog family member C (RHOC) is important during the progression of several types of cancer, including prostate, breast and hepatocellular carcinoma. However, the function of RHOC in cholangiocellular carcinoma (CCC), a highly recurrent and metastatic carcinoma with poor prognosis, remains unclear. The aim of the present study was to investigate the involvement of RHOC in CCC tumor progression. RHOC expression levels were examined in CCC tissues and cells, and adjacent nontumorous bile duct tissues. The effects and molecular mechanisms of RHOC expression on cell migration and invasion were also investigated. The current study demonstrated that RHOC protein was frequently overexpressed in human CCC specimens and CCC cell lines. Downregulation of RHOC inhibited CCC cell invasion and migration partially via inhibition of matrix metalloproteinase 2, 3 and 9 expression. RHOC also modulated the expression of several epithelial-mesenchymal transition (EMT)-associated proteins, including Ecadherin, vimentin, Slug and Snail, to promote to EMT progression. The present results demonstrated that RHOC is important for the invasion and migration of CCC through simultaneous regulation of MMPs and EMTassociated protein, suggesting that RHOC is a potential molecular target for CCC treatment.

According to recent research, Ras homolog gene family member C (RhoC) is confirmed to have a powerful regulatory effect on cell motility mediated by the cytoskeleton, and this process is closely associated with tumor invasion and metastasis. In addition, the epithelial-mesenchymal transition (EMT) process which causes cytoskeleton rearrangement, also plays a pivotal role in tumor invasion and metastasis.Consequently, in the present study, we aimed to ascertain whether RhoC has an effect on the EMT process induced by TGF-beta1 in lung adenocarcinoma cells and whether RhoC promotes tumor invasion by mediating the occurrence of EMT. Based on the findings, we demonstrated that RhoC was an essential mediator of the EMT process in lung adenocarcinoma cell line A549 which was evaluated by observing the morphological characteristics of the cells and by assessing the expression levels of two EMT marker proteins: E-cadherin and vimentin. During the process of EMT in the A549 cells induced by TGF-beta1 (5 ng/ml), upregulated RhoC protein and RhoC activity were detected, which was associated with the enhanced invasive capability of the cells in vitro. Conversely, downregulation of the expression of RhoC by shRNA markedly impeded EMT progression as well as the invasion of A549 cells. Our results may provide a novel target towards the prevention of metastasis in advanced lung adenocarcinoma.