Expression Of Tim-3in Hepatocellular Carcinoma And Its Significance

Background and Objectives:Primary liver cancer is one of the common malignant tumors. It is the fifth most commonly diagnosed cancer worldwide and the third leading cause of cancer death. An estimated750,000new liver cancer cases and700,000cancer deaths occurred worldwide per year.Half of these cases and deaths were estimated to occur in China. Among primary liver cancers, hepatocellular carcinoma (HCC) represents the major histological subtype, accounting for70%to85%of the total liver cancer burden worldwide.78%of HCC was attributable to chronic infection with Hepatitis B virus(HBV)(53%) and Hepatitis C virus(HCV)(25%). In recent years, treatment of HCC has made great advance, however, its overall survival remains unsatisfactory on account of its highly metastasis rate and highly recurrence rate. Biological characteristics of the carcinomas is the fundamental prognostic factors, whose most significant performance are metastasis and recurrence of cancer. Therefore, it is demonstrated both theoretical significance and clinical value in empirical research of proliferation, invasion and metastasis of hepatocellular carcinoma cell.T cell immunoglobulin and mucin domain3(Tim-3) was detected firstly in terminally differentiated Thl cell, which is the surface marker to distinguish Thl cell from Th2cell. In advanced studies, it was reported that Tim-3is expressed in several cell subsets include CD8T cell, Regulatory T cells(Treg), Th17, dendritic cell(DC), natural killer cell(NK), macrophagocyte and other lymphocyte subsets, and Tim-3plays an important role in regulating the secretion of cytokines, through which it participates tumor immunity in multi-cellular level. Recently, it was reported that unusual expression in melanoma cell can decrease the cell adhesion ability and promote tumor progression. Zhuang etc also found that Tim-3highly expresses in non-small cell lung cancers(NSCLC), which is the independent prognostic factor for these patients. However, up to date, there are no similar studies on the association of Tim-3with prognosis in HCC, which needs further researches.In this study, we firstly investigate the expression of TIM-3in HCC tissue and its clinical significance. Further study involves how the expression of TIM-3in HCC tissue to affect tumor progression. In addition, the result elaborates the value of TIM-3in HCC diagnosis, treatment and prognosis.Methods:1. Specimen collection20HCC patients undergoing curative resection were recruited into this study from October2012-August2013,and we collected specimens consist of tumor tissues and corresponding adjacent tissues;4normal liver tissues were collected from patients who suffered from hepatic hemangiomas or liver injury. We cryopreserved two HCC cell lines(HepG2、SMMC7721) and one normal liver cell line (LO2) in lab.2. Detection the expression of Tim-3in HCC tissues(1) Tissues were taken from selected individuals for use in real-time fluorescent quantitive polymerase chain reaction (Real-time PCR) and Western blot assays (20tumor tissues and adjacent tissues,4normal liver tissues). We analysed expression difference between them, and we further studied the relevance of Tim-3expression in HCC with clinicopathological characteristics of the patients.(2) We used real-time PCR and Western blot assays for detecting TIM-3mRNA expression levels and TIM-3protein expression levels in HepG2,SMMC7721, LO2. We analysed expression difference between them and selected the most significant cell lines for further experiments.3.Research on the relationship between TIM-3expression level and the biological characteristics such as liver cancer cell proliferation and migration:Hepatocellular carcinoma cells were transfected with siRNA by using LipofectamineTM2000. The proliferation and migration potential of hepatocellular carcinoma cells was evaluated after Tim-3gene silence by cell growth curve MTT assay and wound healing assay.Results:1. Tim-3expression in hepatocellular carcinoma tissues is significantly higher than that in the adjacent tissues and normal liver tissues. And Tim-3expression levels in hepatocellular carcinoma tissues are correlated with pathological differentiation and portal vein tumor thrombosis. In contrast, there were no significant differences in the expression of Tim-3among different age, gender,serum AFP, HBV infection, cirrhosis, tumor size, tumor number, TNM stage, Child-Pugh class etc.2. Tim-3mRNA and protein expression levels in HepG2and SMMC7721are significantly higher than in L02. After siRNA transfection, the protein expression of Tim-3in experimental group was significantly lower than that of control group. Compared with control group, the proliferative activity and the migration distance decreased significantly. The results suggested that Tim-3can promote hepatocellular carcinoma cells proliferation and migration.Conclusions:1. Tim-3expression increases in HCC, and its abnormal expression may correlate with invasion, metastasis abilities of tumor.2. Tim-3expression increases in hepatocellular carcinoma cell lines, which may promote the proliferation, migration abilities of hepatocellular carcinoma cell.