A Research About The Expression And Mechanism Of INPP4B In EBV-associated Gastric Cancer

Gastric cancer is one of the most common malignant tumors of the digestive tract in the world.Its development is a multi-factor and multi-phase long-term process involving the activation of oncogenes,the inactivation of tumor suppressor genes,and intracellular signaling.Pathway anomalies and multiple biological factors work together.Studies have suggested that Phosphatidylinpsitol-3-kinase(PI3K)/Protein kinase B(PKB/Akt)/Mamalian target of rapamycin(m TOR)signal pathway plays an important role in the regulation and development of tumors,mediates the activation of downstream signaling molecules,and regulates important processes such as tumor proliferation,invasion,migration,differentiation,apoptosis,and angiogenesis.At present,there are many studies on PI3K/Akt/m TOR signaling pathways,but the specific pathways and mechanisms are not fully understood.Studies have shown that PTEN,as a tumor suppressor gene,blocks the PI3K/Akt/m TOR signaling pathway and inhibits cancer by inhibiting Akt phosphorylation.The NPP4 B gene(inositol polyphosphate 4-phosphatase type II,INPP4B)exerts a tumor suppressor effect similar to the PTEN gene in the PI3K/Akt/m TOR signaling pathway,but the specific mechanism of action has not been clearly studied.Epstein-barr virus(EBV)is a common biological pathogenic factor in the development of gastric cancer.Some studies suggest that epigenetic abnormalities play an important role in the development of Epstein-Barr virus associated gastric carcinoma(EBVa GC).The role of DNA methylation in the EBV genome determines the type of latency,and CpG island methylation in the promoter region of the tumor suppressor gene can lead to abnormal cell growth.Studies have shown that Epstein-Barr virus is the first viral factor that can be found to encode micro RNAs,and its encoded micro RNA plays a key role in immune evasion during cell growth.In this study,real-time quantitative PCR and Western blotting were used to study the transcription and expression levels of INPP4 B gene in human gastric cancer cell lines,and to explore the differences in the transcription and expression levels of INPP4 B gene in EBV positive and negative cell lines.Methylation-specific PCR was used to detect the methylation status of CpG island in the promoter region of INPP4 B gene in EBV-positive and negative cell lines,to analyze the effect of EBV infection on methylation status,and to apply methylation inhibitor to human gastric cancer cells.The system was processed to investigate the effect of methylation status of CpG island in the promoter region of INPP4 B gene on gene expression level.OBJECTIVE: To detect the expression level of INPP4 B gene and the methylation status of CpG island in EBV positive and negative gastric cancer cell lines,and to explore the effect of methylation status of CpG island in the promoter region of INPP4 B gene on gene expression level.Methods: EBV-positive and negative gastric cancer cell lines were selected as the study subjects.Real-time quantitative PCR(real-time q PCR)and Western blot(WB)techniques were used to detect the transcription of INPP4 B gene in cells.And the expression level,and methylation-specific PCR(MSP)was used to detect the methylation status of CpG island in the promoter region of INPP4 B gene in EBV-positive and negative cell lines.RESULTS: Before treatment with EBV positive and negative gastric cancer cell lines as methylation inhibitors,the methylation level of CpG island in the promoter region of INPP4 B gene was decreased after methylation inhibitor treatment,and the transcription and expression levels of INPP4 B gene were increased.Conclusion: CpG island methylation in the promoter region is one of the important mechanisms of INPP4 B gene inactivation,and methylation inhibitor treatment can up-regulate the transcription and expression of INPP4 B gene in EBV-positive and negative gastric cancer cell lines.