Meta-analysis And Preliminary Molecular Mechanism Of Rs1380576 In MDM4 Gene Associated With Cancer Risk

As a main factor that threaten human health,cancer has become a heavy burden on society and family due to its incurable and high mortality.The pathogenesis of cancer is complex,and previous studies have shown that genetic factors are important driving factors for the formation and development of cancer.Currently,the most researched genetic factor in cancer is the p53 signaling pathway.As a main negative regulator of p53 protein,the imbalance of MDM4 protein level will directly lead to p53 abnormal function,thus promoting the formation and growth of cancer.The rs1380576 is in the first intron of the MDM4 gene,but conclusions of previous researches that reported rs1380576 and cancer risk are inconsistent,in addition molecular mechanism of this SNP promotes cancer risk has not yet been reported.Therefore,on the basis of previous studies,this study raises two scientific questions:1)Is there any correlation between rs1380576 and cancer risk?2)what is its mechanism of function?In order to investigate whether rs1380576 associated with cancer risk,this study systematically evaluates and summarizes the existing literatures to obtain comprehensive and objective conclusion through Meta-analysis.Based on this purpose,we found 12 reports of rs1380576 and cancer in different databases,then screened out 7 studies that reported rs1380576 associated with cancer risk,extracted the original data of these literatures and evaluated the original data.Finally,4 papers that passed the evaluation were included in the final meta-analysis.The result of the meta-analysis shows that the CG+CC allele of rs1380576 was associated with increased cancer risk(RR=1.25,I~2=0.0%).Meta-analysis shows that rs1380576 is associated with cancer risk,Next:What is the mechanism of rs1380576 function?Because rs1380576 is located in the intron region,the most common mechanism of intron SNP has been identified as promoter or enhancer.In order to explore whether rs1380576 has enhancer or promoter activity,this study constructed a recombinant p GL3-Promoter and p GL3-Enhancer vector containing rs1380576 different allele.The results show that there was no significant difference in the luciferase activity of the G and C allele after transfected the recombinant vector into HEK293,A375 and A549 cell lines.Then this study further explores the transcription factors binding ability between rs1380576 G and C allele by EMSA.The result shows that neither the G and C allele of rs1380576 can bind transcription factors.In summary,this study first conducted a Meta-analysis to conclude rs1380576and cancer risk.Meta-analysis shows that the CG+CC was significantly associated with increased cancer risk.Subsequently,the function of rs1380576 was preliminarily explored through in vitro functional experiments.Dual-Luciferase reporter gene assay shows that rs1380576 had no promoter and enhancer activity.Further EMSA also reveals that rs1380576 couldn’t bind transcription factors.All experimental evidence preliminarily proves that rs1380576 is not a functional SNP,which means that rs1380576 is associated with cancer risk caused by gene linkage,functional SNP that is completely linked with rs1380576 analysis is needed to reveal mechanism that MDM4 gene regulates cancer development.