| Background & ObjectiveHepatocellular carcinoma (HCC) is the sixth most common carcinoma worldwide and has nearly one million new cases every year. Hepatocellular cancer was regulated by a variety of tumor related genes, including the activation of oncogene and inactivation of tumor suppressor gene. However, the exact mechanism is still unknown. SCIN is a Ca2+-dependent filamentous actin (F-actin) regulatory protein. It regulates the polymerization and depolymerization of F-actin. As is considered that the abnormal expression of SCIN can promote the formation of tumors by disrupt the cytoskeleton structure. Researches find that SCIN has a close relationship with the progression, development and biological behavior of various tumors. CyclinAl is a type of cell cycle regulation protein which play an important role in the process of cell proliferation and division. The phosphorylation of STAT3 was found to be responsible to lots of tumors.This study aimed to solve the following problems:(1) Detecting the expression of SCIN in HCC samples. (2) The correlation between SCIN expression level and clinicopathologic characteristics. And the relationship between SCIN expression level and prognosis of HCC patients. (3) The biological function of SCIN in HCC cells. (4) The molecular mechanism between SCIN and HCC.Methods1.Real-time PCR and Western blot were used to detect the expression of SCIN in HCC tissues and adjacent normal liver tissues from 12 patients. Another 60 paired HCC tissues were detected by immunohistochemical method.2.The relationship between SCIN expression level and clinicopathologic characteristics of HCC patients was analyzed using χ2 and t-test.3.The relationship between SCIN expression level and prognosis (including DFS and OS) of HCC patients was analyzed using Kaplan-Meier and verified by Log-rank test.4.COX proportional regression model was performed to analyze whether SCIN was an independent risk factor affecting the prognosis of HCC patients.5.PcDNA3.1-SCIN plasmid containing the SCIN open reading frame and a GV115 plasmid expressing SCIN siRNA were constructed. These two plasmid were transfected into HCC cells and stable expressing SCIN or SCIN shRNA were selected using G418 or flow cytometry, respectively.6.MTT assay and cell cycle test by FACS were performed to assess the proliferation capacity of cells; wound hell assay and Boyden Chamber assay were performed to assess the metastatic capacity of cells.7.The nude mouse animal model was used to analyze the proliferation capacity in vivo.8.Extract the cell proteins and analyze some common signal pathways by Western Blot assay.Resultsl.The expression level of SCIN was down-regulated in HCC tissues and was positively associated with the clinicopathologic features (diameter).2.The Disease-free survival and Overall survival of high-SCIN patients were longer than those of low-SCIN patients. SCIN can be used as an indicator to judge the prognosis of HCC patients.3.Forced SCIN expression in HCC cells inhibited cell proliferation in vitro, while SCIN knockdown promoted these processes in vitro and in vivo.4.SCIN down-regulated CyclinAl expression and inhibited the phosphorylation of STAT3, thereby restraining the proliferation of HCC cells.ConclusionsThe lower SCIN expression was found in HCC tissues. SCIN is an independent risk factor affecting RFS and OS after curative resection. Elevated SCIN levels in HCC cell lines inhibited their proliferation by down-regulating the expression level of CyclinAl and p-STAT3. These results indicated that SCIN may be a new criterion and a potential therapeutic target. |
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