简介:AIMToinvestigatetherolesandinteractionsofmutThomolog(MTH)-1andhypoxia-induciblefactor(HIF)-1αinhumancolorectalcancer(CRC).METHODS:TheexpressionanddistributionofHIF-1αandMTH-1proteinsweredetectedinhumanCRCtissuesbyimmunohistochemistryandquantitativerealtimepolymerasechainreaction(qRT-PCR).SW480andHT-29cellswereexposedtonormoxiaorhypoxia.ProteinandmRNAlevelsofHIF-1αandMTH-1wereanalyzedbywesternblottingandqRT-PCR,respectively.InordertodeterminetheeffectofHIF-1αontheexpressionofMTH-1andtheamountof8-oxodeoxyguanosinetriphosphate(dGTP)inSW480andHT-29cells,HIF-1αwassilencedwithsmallinterferingRNA(siRNA).GrowthstudieswereconductedoncellswithHIF-1αinhibitionusingaxenografttumormodel.Finally,MTH-1proteinwasdetectedbywesternblottinginvivo.RESULTS:HighMTH-1mRNAexpressionwasdetectedin64.2%ofcases(54/84),andthiswassignificantlycorrelatedwithtumorstage(P=0.023)andsize(P=0.043).HIF-1αproteinexpressionwascorrelatedsignificantlywithMTH-1expression(R=0.640;P〈0.01)inhumanCRCtissues.HypoxicstressinducedmRNAandproteinexpressionofMTH-1inSW480andHT-29cells.InhibitionofHIF-1αbysiRNAdecreasedtheexpressionofMTH-1andledtotheaccumulationof8-oxo-dGTPinSW480andHT-29cells.Intheinvivoxenografttumormodel,expressionofMTH-1wasdecreasedintheHIF-1αsiRNAgroup,andthetumorvolumewasmuchsmallerthanthatinthemocksiRNAgroup.CONCLUSION:MTH-1expressioninCRCcellswasupregulatedviaHIF-1αinresponsetohypoxicstress,emphasizingthecrucialroleofHIF-1α-inducedMTH-1intumorgrowth.