The Influence Of RhoC Gene On Invasion And Metastasis Of Hepatocellular Carcinoma

Hepatocellular carcinoma(HCC) is one of the most common tumors in the world,and is currently the second-leading cause of cancer death in our country.In spite of recent advances in diagnosis and treatment, such as the development of imaging techniques and surgical treatment ,have improved the curative rate,the long-term prognosis of HCC is still poor.The high incidence of recurrence is the most crucial prognostic factor for patient with HCC.Pathologic and genetic researches showed that recurrence of HCC could be devided into 2 types:multicentric occurrence of HCC and intrahepatic metastasis of HCC.Cancer metastasis is a multistep processes that involves cells detachment from the primary tumor,entering into the vascular or lymphatic system,dispersing through the circulation,and extravasation and proliferation in the target organ.However,the molecular and cellular mechanisms of intrahepatic metastasis of HCC are not fully understood.Recently,Clark et al reported that the overexpression RhoC of tumor can stimulate metastasis of the tumor.In vitro RhoC overexpression in the poorly metastatic human melanoma cell line can promote it to change to highly metastatic cell line,which indicated that the products of RhoC gene may be important in metastasis of tumor,rather than an indirect consequence of the alreation of tumor growth enviroment,Rho gene may be the molecular switch of tumor invasion and metastasis. Whether or not the overexpression of RhoC sufficient to induce the overexpression of the other metastasis-associated genes is still unknown. This study includes three parts:Part 1: The reconstruction of the plasmid (pcDNA3.1-RhoC)Objective :To establish an experimental model for exploring the role of RhoC gene in the invasion and metastasis of HCC.Methods: The RhoC gene was digested with restricted enzyme Hindlll and Xbal,and direct cloned to pcDNA3.1 to reconstruct the plasmid pcDNA3.1 -RhoC. The reconstructed plasmid(pcDNA3.1 - RhoC) and the vector-alone ( pcDNA3.1) was transfected into HEPG2 cells with LIPFECTAMINEæ©°eagent. After selected with hygromycin, the transcription and translation of RhoC gene were analysed with the RT-PCR and immunohistochemical stain.Results :The results suggest that the recombinant plasmid could express steadily.RhoC protein efficiently under the control of vector's promoter(p < 0.01).Conclusions: The modified tumor cells(HEPG2-RhoC) could be used to study the effect of RhoC protein on the invasion and metastasis of hepatocellular carcinoma.