TGF-β Regulates ITIH1 Through M6A RNA Methylation To Promote Invasion And Metastasis Of Hepatocellular Carcinoma

Hepatocellular carcinoma(HCC)is one of the common malignant tumors in China,and its mortality rate has always been among the top five in malignant tumors.TGF-βsignaling pathway plays an important role in the invasion and metastasis of advanced liver cancer,but its mechanism is still unclear.At the same time,studies have shown that m6 A RNA methylation is closely related to TGF-β signaling pathway in the invasion and metastasis.In this study,we found that SMAD3 can bind METTL3 and enhance their binding when activating the TGF-β signaling pathway.In vitro migration and invasion experiments found that METTL3 can promote the migration and invasion of HCC cells.Through sequencing and database analysis,we found that the TGF-β pathway and METTL3 co-regulate the ITIH1.Further studies show that SMAD3 and METTL3 complexes can directly bind to the m6 A methylation region of ITIH1 m RNA and inhibit its expression.And we constructed ITIH1 knockdown and overexpressing HCC cells,and in vitro and in vivo experiments proved that ITIH1 can inhibit the invasion and metastasis of HCC.Through mass spectrometry analysis,we found that ITIH1 can bind to ITGA5 /ITGB1,and then we found that ITIH1 binds to the extramembrane domain of ITGA5 /ITGB1 and inhibits its downstream FAK / SRC pathway activation.Validation of tissue samples from HCC patients found that SMAD3 and METTL3 were negatively correlated with ITIH1,and that low expression of ITIH1 was associated with poor prognosis of HCC patients.In summary,this study explores the molecular mechanism of TGF-β-METTL3-ITIH1 axis in promoting HCC invasion and metastasis from the in vivo and in vitro levels,and provides new ideas and theoretical for the treatment of HCC.