Expression And Function Of P54^nrbin Hepatocellular Carcinoma

Background and purpose:Primary hepatocellular carcinoma(HCC)is the most common primary malignancy of the liver,accounting for the second largest number of cancer-related deaths worldwide[1,2].The incidence is highest in the East Asia and hepatitis B virus epidemic areas,and the number of liver cancers in China accounts for more than half of the world’s population.The etiology and pathogenesis of HCC have not been identified yet and multiple risk factors may be involved.The main risk factors are cirrhosis and viral hepatitis(chronic hepatitis B and hepatitis C),toxic substances(alcohol and aflatoxin),metabolism(diabetes and nonalcoholic liver disease,hereditary hemochromatosis),and immune-related hepatitis(primary biliary cirrhosis and autoimmune hepatitis)[3].Given these various etiologies,HCC is therefore a complex disease characterized by gradual accumulation of genetic and epigenetic changes,including mutations,translocations,amplifications or deletions,chromatin remodeling,changes in DNA methylation and non-coding RNA disorders[4-6].Due to the occult onset of HCC,most patients have entered the middle or late stages and have missed the best time for treatment.Therefore,it is particularly important to find genes that are helpful in the diagnosis,treatment,and prognosis of liver cancer.The occurrence,development,invasion and metastasis of hepatocellular carcinoma is a complex process that requires the participation of multiple stages,steps,and genes.In recent years,the signal transduction pathway,abnormal protein expression,and related gene expression regulation during this process have been investigated.The increasing number of studies has improved our understanding of HCC.Howerver,there are still many things worth exploring in the pathogenesis of liver cancer.Therefore,researches on liver cancer related genes can improve our understanding of its pathogenesis.P54nrb is a multifunctional nuclear RNA-binding protein with functions in transcription regulation,post-transcriptional processing and transportation,DNA damage repair,regulation of circadian rhythm and cell cycle.It has been reported that P54nrb is highly expressed in malignant melanoma[7],malignant pleural mesothelioma[8],malignant breast cancer[9,10],neuroblastoma[11],prostate cancer[12]and esophageal cancer[13],showing that P54nrb may be an oncogene for many types of tumors.In vivo and in vitro studies have shown that P54nrb is involved in the formation and metastasis of tumors.However,studies on P54nrb and hepatocellular carcinoma have not been reported yet.In this study,we studied the expression and function of P54nrb in HCC,and explored the role of P54nrb in the development of HCC,and therefore provided a reference for further elucidating the pathogenesis of HCC.Methods and contents:1.We analyzed the relationship between P54nrb expression and prognosis in HCC gene chip database,and the difference of P54nrb expression in hepatocellular carcinoma and adjacent tissues;2.The immunohistochemical SP method was used to detect the expression level of P54nrb in hepatocellular carcinoma and adjacent tissues from the protein level.The SPSS Statistics 20.0 statistical analysis software was used for data processing.Chi-square test was used to analyze the expression difference between cancer tissues and adjacent tissues.The relationship between the expression of P54nrb in hepatocellular carcinoma and clinical characteristics was analyzed to explore the role of P54nrb in the development of hepatocellular carcinoma.Kaplan-Meier survival curves were used to analyze the relationship between P54nrb expression and OS and PFS.Log-rank test was used to analyze the differences in survival curves.Univariate and multivariate survival analysis was performed using a Cox regression model to evaluate the prognostic significance of P54nrb protein in patients with HCC.3.We used siRNA to knockdown P54nrb in LM3 and Huh7 cells.Transfection efficiency was validated by qRT-PCR and Western blot.CCK-8 proliferation assay and transwell migration assay were used to verify the effect of P54nrb on the proliferation and migration ability of HCC cell lines.Results:1.Analysis of the TCGA liver cancer microarray database revealed that P54nrb is associated with a poor prognosis.OS and PFS were significantly shorter in patients with high P54nrb expression.In addition,P54nrb expression was significantly higher in hepatocellular carcinoma than in adjacent tissues.2.Tissue microarray data showed that the expression of P54nrb was significantly higher in hepatocellular carcinoma than in adjacent tissues(P<0.001).The expression level of P54nrb protein was positively correlated with the AFP level(P=0.033).The expression of P54nrb was negatively correlated with the overall survival time of patients(P=0.023),patients with high expression of P54nrb had a poorer prognosis than patients with low expression of P54nrb(P=0.023).Subgroup analysis showed that high P54nrb expression was associated with shorter OS in men(P=0.020),age<50 years(P=0.006),HBsAg positive(P=0.004),and Edmondson I-II(P=0.016)patients.High P54nrb expression was related to shorter PFS in AFP≥25 ng/ml(P=0.035),HBsAg positive(P=0.046),single tumor nodules(P=0.040),negative microvascular invasion(P=0.014),intact capsule(P=0.026)and TNM stage I(P=0.014).Cox single-factor regression analysis showed that Edmondson’s pathological grade(P=0.006)and P54nrb expression(P=0.028)were significantly correlated with shorter overall survival time of patients with HCC.Multivariate regression analysis showed that the expression level of P54nrb(P=0.029)and Edmondson’s pathological grade(P=0.036)both served as independent prognostic factors for patients with HCC.3.Knockdown of P54nrb significantly inhibited the proliferation and migration of HCC cells.Conclusions:P54nrb is highly expressed in hepatocellular carcinoma,and its expression level is significantly associated with the prognosis of hepatocellular carcinoma.P54nrb can promote the proliferation and migration of hepatoma cells.