Expression And Clinical Significance Of Mitochondrial Transcription Elongation Factor(TEFM) In Hepatocellular Carcinoma(HCC)

Background and Objective:HCC is the most common primary liver cancer,the sixth most common cancer in the world,and the second leading cause of cancer-related deaths.Liver cancer can be treated by surgical resection,liver transplantation,liver-directed therapy and systemic therapy,but the 3-year survival rate for liver cancer is only 12.7%,and the median survival time is 9 months.Therefore,in-depth study of the pathogenesis of HCC and identification of oncogenes or tumor suppressor genes involved in the development of HCC are of great significance to the diagnosis and treatment of HCC.TEFM gene was also named C17orf42,which is located in human 17q11.2,contains 4 exons,the m RNA length is 1357 bp,and the encoding one consists of 360 amino acid residues Protein.Agaronyan K et al.reported for the first time in Science that TEFM is a key molecular switch that regulates the conversion between transcription and replication of the mitochondrial genome.Studies have confirmed that TEFM has the functions of regulating mt DNA transcription extension and anti-transcription termination,and it participates in the post-transcriptional processing of mitochondrial RNA,which is closely related to the production of mitochondrial energy and the occurrence of mitochondrial diseases.With the in-depth study of TEFM,it is found that the deletion or abnormal expression of TEFM gene may lead to the occurrence of malignant tumors such as pancreatic cancer,type I neurofibromas and brain gliomas,but the expression of TEFM protein in HCC tissues and the clinical disease of HCC There is no research report on the correlation of physical characteristics.This topic will lay a theoretical foundation for elucidating the role of TEFM in the occurrence and development of HCC,and also provide clues for early clinical diagnosis of HCC and potential molecular therapeutic targets.Methods:The TCGA,Oncomine,GEPIA and c Bioprotal databases were used to analyze the correlation between TEFM expression level and the pathological characteristics and prognosis of HCC patients.TIMER platform was used to analyze the relationship between TEFM expression in HCC and tumor immune infiltrating cells.Collected 70 clinical cases of tissue microarray,using immunohistochemistry technology to detect the protein expression level of TEFM in HCC tissues and adjacent tissues.Western blotting was used to detect the tissue expression profile of TEFM in C57 mice,Western blotting was used to detect the difference of TEFM protein expression in human normal hepatocytes and 6 kinds of HCC cells.And the expression of TEFM protein in Hep G2 cells with different serum concentration,different serum starvation time and serum recovery period.Results:1.Analysis of public tumor databases found that TEFM is highly expressed in HCC,and the expression of TEFM m RNA in HCC patients is significantly related to gender,AFP and vascular invasion.In the overall survival(OS)of HCC patients,the survival time of TEFM high expression group was significantly shorter than that of TEFM low expression group(P<0.05).Patient age,vascular invasion,and TEFM expression are independent factors that affect the prognosis of HCC patients(P<0.05).In addition,among the mitochondrial transcription regulation genes,the expression levels of TFAM,TFB1 M,MTERF1,MTERF2,MTERF4 and NRF1 genes are positively correlated with the expression levels of TEFM genes(P<0.05).Among the HCC marker genes,TP53,RASSF1,CDKN2 A,EZH2 and MKI67 gene expression levels are positively correlated with TEFM gene expression levels(P<0.05).The expression of TEFM was positively correlated with bladder cancer CD4+T cells,macrophages,neutrophils and dendritic cells(P<0.05).2.Tissue chip technology analysis found that the expression of TEFM protein in HCC tissue was significantly higher than that of its corresponding adjacent tissues.Correlation analysis between the relative expression level of TEFM in tissue chip and relevant pathological parameters of HCC patients.The results showed that the relative expression of TEFM protein was significantly correlated with the AFP content of HCC patients(P<0.001).The Kaplan-Meier prognostic model was used to analyze the pathological parameters and relative expression levels of TEFM in HCC patients and the prognosis of HCC patients.The results showed that the relative expression level of TEFM was not significantly correlated with OS and DFS in HCC patients.3.Western blot results showed that the expression level of TEFM protein in the brain,heart,liver,ovary and skeletal muscle of C57 mice was relatively high.Compared with human normal hepatocytes(THLE-2)cultured in vitro,the expression of TEFM protein is in 6 human HCC cell lines(SMMC-7721,BEL-7402,Hep3 B,Hep G2,QGY-7701 and SK-Hep1)were significantly up-regulated(P<0.05).The expression of TEFM protein was the lowest in BEL-7402 cells and the highest in Hep3 B cells.With the gradual decrease of serum concentration,the expression level of TEFM protein gradually decreases.With the prolongation of serum starvation time,the expression of TEFM protein gradually decreased.In addition,the TEFM protein expression gradually increased after the serum recovery time from 0 h to 12 h.After 24 h of serum re-stimulation,the TEFM protein expression began to decrease.Conclusion:1.Tumor database analysis shows that TEFM expression is increased in HCC,and the high transcription level of TEFM is closely related to the patient’s gender,serum AFP level and vascular infiltration.Gene expression correlation analysis showed that the m RNA expression level of TEFM in HCC was significantly correlated with the expression levels of some mitochondrial transcription regulation genes(TFAM,TFB1 M,MTERF1,MTERF2,MTERF4 and NRF1)and HCC marker genes(TP53,RASSF1,CDKN2 A,EZH2 and MKI67).In addition,TEFM was significantly correlated with HCC tumor immune infiltrating cells(CD4+T cells,macrophages,neutrophils and dendritic cells).2.The experimental results show that in HCC tissues and normal liver tissues,the expression of TEFM protein is mainly located in the cytoplasm,and the relative expression of TEFM protein has a significant correlation with the AFP content of HCC patients.The functional verification experiment of TEFM shows that the expression of TEFM protein in C57 mice is tissue-specific,and it is highly expressed in the brain,heart,liver,skeletal muscle,ovary and other tissues with rich mitochondria content and strong metabolism,and in the spleen,kidney and intestines.Relatively low expression in tissues.In addition,compared with normal liver cells,TEFM protein expression increased in HCC cells,and TEFM protein content decreased after serum starvation treatment.