Study On Malignant Hyperplasia And Prognosis Of PKM2 In Hepatocellular Carcinoma

BackgroundLiver cancer is one of the digestive malignant tumors,the global incidence of mortality accounted for fifth.Hepatocellular Carcinoma(HCC)is the most common pathological type of liver cancer,which is insidious onset,highly aggressive and poor prognosis.Because of above characteristics,the majority of patients were already in the advanced stage.Large volume,portal vein invasion and distant metastasis bring a lot of difficulty treatment.So far,the treatments of HCC have surgery,Transarterial Chemoembolization(TACE),chemotherapy,local radiotherapy and sorafenib,but the treatmental effect of long-term is not satisfied.Meanwhile,HCC lacks other effective tumor markers except AFP in clinical.Therefore,the research on biological targeted therapy of HCC has been paid much attention by researchers.In recent years,Researchers found that glucose metabolism in tumor cells and normal cells are different.Even when oxygen is enough,tumor cells are still anaerobic glycolysis.There are different theories about the mechanism,which plays an important role is a rate limiting enzyme-pyruvate kinase isozyme splice variant(PKs).It has four isomers,M2 is one of them,it has the characteristics of secretion in tumor cells or unlimited reproduction of cells.In recent years,PKM2(pyruvate kinase isozyme splice variant 2)associated with multiple cell signaling pathways in HCC,but the role of PKM2 in HCC is still not clear.AimsThe aims of present study were to explore the PKM2 expression in human HCC tissues and cells lines,discover the relationship between PKM2 and HCC,and elucidate their molecular mechanism,in order to develop novel diagnostic and prognostic methods and potential therapeutic targets.MethodsPKM2 expression in human HCC and adjacent normal tissues were explored using immunohistochemistry,and HCC cells lines compared with normal liver cell were quantified using qRT-PCR.Next,Lentivirus-mediated RNA interference was applied to knockdown and overexpress PKM2 in HCC97 H and HCCLM3.Cell growth was monitored using high content screening.Cell viability was measured by MTT assay.Cell colony-forming capacity was measured by colony formation assay.Cell cycle progression and apoptosis were determined by flow cytometry.Using xenograft model in nude mice to test whether knockdown of PKM2 influenced the tumorigenicity of HCC cells in vivo.The expression of PKM2 in 86 cases of HCC was detected by immunohistochemical method.The relationship between PKM2 expression and clinical pathological parameters,and prognosis of patients were subsequentially analyzed.ResultsThe expression levels of PKM2 in patients with HCC and hepatic carcinoma cell lines were higher than the healthy tissues and normal liver cells.PKM2 can enhance the cell proliferation and resistance to apoptosis in the HCC.Meanwhile,PKM2 can block cell cycles into the G0/G1 and S phase.Furthermore,PKM2 can enhance the ability of HCC colony formation.The expression level of PKM2 was significantly high in the cytoplasm in HCC.Kaplan-Meier analysis revealed that PKM2 expression was strongly associated with survival in HCC patients(P<0.05).The high expression of PKM2 patients was significantly shorter survival time than those with low expression of PKM2(hazard ratio for death,1.14;95% confidence interval,0.92-1.37,P = 0.012).ConclusionsThrough knockdown and over expression,it was found that PKM2 can promote the growth and metastasis,anti-apoptosis of hepatocellular carcinoma cell lines.These functions of PKM2 may contribute to the interactions between STAT3 phosphorylation and apoptosis-related factors.We concluded that PKM2 expression in HCC tissue samples could be used as a prognosis factor for patients with HCC and the highly PKM2 expression was correlated with poor prognosis of HCC patients.