The Relationship Between PKM2 Expression And Radiosensitivity In Liver Cancer

Background Hepatocellular carcinoma(HCC)is one of the three major forms of primary liver cancer and accounts for 85 ? 90% of all primary liver cancers.In recent years,the incidence of liver cancer in China has increased significantly,with about 350,000 new cases of liver cancer every year,and the fatality rate is high.HCC is typically caused by viral hepatitis infection or fatty liver disease.Cryptogenic cirrhosis,which is frequently linked with nonalcoholic steatohepatitis(Nonalcoholic steatohepatitis,NASH)/nonalcoholic fatty liver disease(Nonalcoholic fatty liver disease,NAFLD)in patients with metabolic syndrome,diabetes and obesity,is an increasingly significant cause of HCC.Furthermore,metabolic syndrome itself is also a strong risk factor for HCC.Increasing evidence suggests that diabetes is an independent risk factor for HCC,particularly diabetes controlled by diet,insulin or sulfonylureas.Additionally,a series of metabolic alterations in HCC,including elevated glycolysis,gluconeogenesis,and ?-oxidation levels and reduced tricarboxylic acid cycle and D-12 desaturase levels,were observed.Pyruvate kinase(Pyruvate kinase,PK)catalyzes the last and physiologically irreversible step in glycolysis,the conversion of phosphoenol pyruvate(Phosphoenolpyruvate)to pyruvate via the transfer of a phosphate group to Adenosine diphosphate(Adenosine diphosphate,ADP).In mammals,four PK isoforms exist that are encoded by two genes.The PKLR gene encodes PKL and PKR.The former is exclusive to erythrocytes,and the latter is expressed primarily in the liver,with low expression in the kidney.The PKM1 and PKM2 isoforms are encoded by PKM through alternative splicing of the mutually exclusive exons 9 and 10,which generate 56-amino acid regions that differ at22 residues.PKM1 is mainly expressed in brain,heart,and muscle tissue,whereas PKM2 is expressed in most tumor cells,embryonic tissue and many adult tissues,including the kidney,spleen,lung and intestine.PKM2 plays a central role in maintaining the metabolism program of cancer cells and other proliferating cell types and is over-expressed in a broad range of human cancers.Traditionally,radiotherapy has played a minor role in the treatment of hepatic cancers because of the low tolerance of the whole organ to irradiation,with a limit of 30 ? 35 Gy.The advent of new elegant 3D conformal radiotherapy(3D-CRT)has allowed the tumor to receive a higher dose and the surrounding normal liver tissue to receive a lower dose.3D-CRT has been utilized for HCC in a series of trials,with promising results in Asian countries,including improvements in response rate,disease control and overall survival.3D-CRT is a common therapeutic measure for patients with liver cancer.Objective Studies have confirmed that the expression of PKM2 protein in the pathological tissues of liver cancer is closely related to the prognosis of patients,but whether the protein expression is related to radiotherapy sensitivity has been rarely reported.Methods1.Immunohistochemistry(IHC)and Western Blot(WB)methods were used to detect the expression of PKM2 protein in the pathological tissues of liver cancer and three liver cancer cell lines(smmc-7721,bel-7402 and Hep G2),and the expression of PKM2 protein in the pathological tissues of liver cancer in this study was statistically analyzed.2.Flow Cytometry(FCM)was used to determine the sensitivity of PKM2 expression to radiotherapy.3.Elisa was used to detect and compare the differences of serum AFP levels in patients with different PKM2 protein expressions before and after radiotherapy.4.The effect of radiotherapy was different in patients with different PKM2 protein expression according to the evaluation criteria of solid tumor efficacy(Response evaluation criteria in solid tumors,RECIST)version 1.1.5.Logistic regression analysis was used to investigate the relationship between PKM2 protein expression and radiotherapy sensitivity.Results1.PKM2 positive rate in the pathological tissues of liver cancer is high,and the expression of liver cancer tissues is significantly higher than that PKM2 adjacent tissues.2.PKM2 expression was from high to low SMMC-7721?BEL-7402?HL-7702,at the same time,SMMC-7721 and Hep G2 apoptosis were found to be high expression,proliferation ability increased,apoptosis ability decreased,PKM2 low expression,proliferation ability decreased,apoptosis ability increased.3.The changes of serum AFP in patients with positive expression of PKM2 protein were lower than those with negative before and after radiotherapy(P<0.05).4.Stage III,IV,low differentiation differentiation and positive PKM2 protein were all independent risk factors for liver cancer radiotherapy insensitivity(OR=3.274,5.328,5.942,7.135,POR=0.05).Conclusion1.Increased expression of PKM2 in human liver cancer tissues and cell lines,it can promote the proliferation of liver cancer cells and inhibit the apoptosis of liver cancer cells.2.The changes of serum AFP PKM2 the positive protein expression of liver cancer before and after radiotherapy were lower than those of the negative,and the clinical stage ?,? period and low differentiation,high PKM2 expression are independent risk factors for the development of radiation is notsensitive.