The role of RhoC in the proliferation and apoptosis of hepatocellular carcinoma cells

Department of General Surgery, First Hospital of Jilin University, 71 Xin Min St, Changchun, 130021 Jilin Province, China.
Medical Oncology (Impact Factor: 2.63). 06/2011; 29(3):1802-9. DOI: 10.1007/s12032-011-0003-0
Source: PubMed


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.

7 Reads
  • Source
    • "Previous studies have provided evidence suggesting the critical role of RhoC in promoting progression of different cancers [4]–[8]. Our recent study demonstrated that RhoC was a key regulator of tumor cell growth and apoptosis in HCC cells [9]. These data suggest the potential involvement of RhoC in HCC carcinogenesis and progression. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Ras homologous C (RhoC) is expressed in various cancers, including hepatocellular carcinoma (HCC). In this study, we first analyzed RhoC expression in 46 HCC tissue specimens and found that RhoC expression was significantly increased in HCC tissues compared to the adjacent normal liver tissues. Next, we investigated the role of RhoC in malignant transformation of normal hepatocytes. The HL7702 cell line was stably transfected with a RhoC expression vector and then subjected to cell proliferation, differentiation, colony formation, migration and invasion assays, as well as nude mouse xenograft assays. Gene expressions in these cells were determined using RT-PCR and Western blot. Overexpression of RhoC significantly promoted proliferation and anchorage-independent growth of HL7702 cells, but suppressed cell differentiation, as compared with the parental cells and the empty vector-transfected control cells. Moreover, RhoC overexpression induced migration and invasion of HL7702 cells in vitro. Molecularly, RhoC increased the expression of cell cycle-related genes, matrix metalloprotease 2 (MMP2), MMP9 and vascular endothelial growth factor (VEGF). In addition, RhoC-transfected cells formed tumors in nude mice, whereas vector-transfected HL7702 cells did not form any tumors in nude mice. This study demonstrated the role of RhoC overexpression in malignant transformation of normal human hepatocytes, suggesting that RhoC may function as an oncogene in hepatocytes.
    PLoS ONE 01/2013; 8(1):e54493. DOI:10.1371/journal.pone.0054493 · 3.23 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: Several Rho GTPase-activating proteins (RhoGAPs) are implicated in tumor progression through their effects on Rho GTPase activity. ARHGAP21 is a RhoGAP with increased expression in head and neck squamous cell carcinoma and with a possible role in glioblastoma tumor progression, yet little is known about the function of ARHGAP21 in cancer cells. Here we studied the role of ARHGAP21 in two prostate adenocarcinoma cell lines, LNCaP and PC3, which respectively represent initial and advanced stages of prostate carcinogenesis. Results: ARHGAP21 is located in the nucleus and cytoplasm of both cell lines and its depletion resulted in decreased proliferation and increased migration of PC3 cells but not LNCaP cells. In PC3 cells, ARHGAP21 presented GAP activity for RhoA and RhoC and induced changes in cell morphology. Moreover, its silencing altered the expression of genes involved in cell proliferation and cytoskeleton organization, as well as the endothelin-1 canonical pathway. Conclusions: Our results reveal new functions and signaling pathways regulated by ARHGAP21, and indicate that it could contribute to prostate cancer progression.
    Biochimica et Biophysica Acta 11/2012; 1832(2). DOI:10.1016/j.bbadis.2012.11.010 · 4.66 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Unlabelled: Epithelial-mesenchymal transition (EMT) is a critical step in the metastasis of hepatocellular carcinoma (HCC). BTB/POZ domain-containing protein 7 (BTBD7) regulates EMT-associated proteins implicated in HCC progression. However, the role(s) of BTBD7 in HCC have not been identified. Using highly metastatic HCC HCCLM3 cells, immortalized L02 hepatocytes, metastatic HCC animal models, and three independent cohorts of HCC patient specimens, we aimed to determine the involvement of BTBD7 in HCC metastasis. We show that BTBD7 messenger RNA and protein was highly expressed in HCC cells and tumor tissues, with such expression being associated with: enhanced cell motility, venous invasion, and poor prognosis. BTBD7 promoted HCC angiogenesis and metastasis in vitro and in vivo, but did not influence cell proliferation or colony formation. BTBD7 enhancement of HCC invasion and EMT phenotype occurred through activation of a RhoC-Rock2-FAK-signaling pathway, resulting in matrix metalloproteinase-2/9 production and microvessel formation. Applying a predictive risk score model, Cox regression analysis revealed that high BTBD7 expression integrated with high microvessel density was a powerful independent predictive factor of HCC clinical outcome. Conclusion: The present study identifies BTBD7 as a novel candidate prognostic factor and a potential therapeutic target of HCC. (HEPATOLOGY 2013; 57:2326-2337).
    Hepatology 06/2013; 57(6). DOI:10.1002/hep.26268 · 11.06 Impact Factor
Show more