The Role Of HIF-1α Gene Silencing In The Hypoxia And Epithelial-mesenchymal Transition Of Colorectal Cancer

Objectives:To study the effect of HIF-1α gene silencing on the proliferation,invasiveness andexpression of Snail＆E-cadherin of SW480cells， and approach the roles andmechanisms of HIF-1α in the hypoxia and epithelial-mesenchymal transition ofcolorectal cancer.Methods:We have used chemical inducing process with cobalt chloride（CoCl2）to establishthe hypoxia cell model of colorectal cancer SW480cells,we designed and synthetizedthe small interference RNA(HIF-1α-siRNA),and got the cells transfection, the groupswas divided into: blank group,negative control group and gene interferencegroup.Methyl thiazolyl tetrazolium(MTT) method was used to detect the proliferationcapability of the colorectal cancer SW480cells,extraorgan invasion experiment(Transwell methed) was applied to evaluate the cells’ invasion and transferencecapability, the mRNA and protein expression levels of HIF-1α、Snail and E-cadherinwere detected by real time PCR(RT-PCR) and Western blot respectively.Results:In the hypoxia microenvironment,MTT disclosed that both the OD value andsurvival rates of gene interference group were decreased compared with the blank andnegative control groups(P<0.05);Transwell results showed that most of the cells in theblank and negative control groups penetrated the matrix membrane and polycarbonate membrane and had been dyed to be blue color by hematoxylin,but only a few cellspenetrated the membrane and had been dyed to be blue in gene interference group，itsinvasion and migrateon rate were decreased(P<0.05);RT-PCR and Western blotdisplayed that the expression of mRNA and protein of HIF-1α and Snail in SW480cellsof gene interference groups were decreased compared with the blank and negativecontrol groups,and the expression of mRNA and protein of E-cadherin was increasedobviously (P<0.05),furthermore,there is a significant positive correlativity between theHIF-1α and Snail,and there is a significant negative correlativity between both them andE-cadherin conspicuously(P<0.05).Conclusion:1.The extraorgan proliferation,invasion and migration capabilities of the colorectalcancer SW480cells were inhibited by HIF-1α gene silencing;2.In colorectal cancer SW480cells,the expression of HIF-1α had positivecorrelation with Snail and negative correlation with E-cadherin;3.One possible mechanisms were RNAi gene silencing HIF-1α affected SW480cells directly to inhibited the proliferation,invasion and migration,another one maybe itdecreased Snail expression and promote E-cadherin expression,then restrained theincidence and development of EMT.