简介：AIM:ToexploreexpressionsofPIK3CAintheprogressionofgastriccancerfromprimarytometastasisanditseffectsonactivationofphosphatidylinositol3-kinase(PI3K)/Aktpathway.METHODS:mRNAandproteinlevelsofPIK3CAwereassessed,respectively,byreal-timequantitativepolymerasechainreactionandimmunohistochemistryinspecimensofnormalgastricmucosa,primaryfociandlymphnodeanddistantmetastasisofgastriccancer.AktandphosphorylatedAktproteinwerealsoexaminedbyWesternblottinginthesetissues,inordertoanalyzetheeffectofPIK3CAexpressionlevelchangesontheactivationofPI3K/Aktsignalingpathway.RESULTS:PIK3CAmRNAinlymphnodemetastasiswereapproximately5and2foldshigher,respectively,thanthatinthecorrespondingnormalgastricmucosaandprimarygastriccancertissues(P<0.05),whilenostatisticalsignificancewasfoundcomparedwithdistantmetastasis.Immunohistochemically,PIK3CAproteinexpressionwasdiscoveredin7(35%)specimensof20primaryfocivs10(67%)of15oflymphnodemetastasisor11(61%)of18ofdistantmetastasis(35%vs67%,P=0.015;35%vs61%,P=0.044).WiththeincreasedlevelofPIK3CAexpression,thetotalAktproteinexpressionremainedalmostunchanged,butp-Aktproteinwasupregulatedmarkedly.CONCLUSION:IncreasedexpressionofPIK3CAisexpectedtobeapromisingindicatorofmetastasisingastriccancer.Up-regulationofPIK3CAmaypromotethemetastasisofgastriccancerthroughaberrantactivationofPI3K/Aktsignaling.

简介：AIM:Toinvestigatetheassociationbetweenendogenousgeneexpressionandgrowthregulationincludingproliferationandapoptosisinducedbytransforminggrowthfactor-β1(TGF-β1)inhumangastriccancer(GC)cells.METHODS:Reversetranscriptionpolymerasechainreaction(RT-PCR)wasperformedtodetectthemaincomponentsoftheTGF-β1/SmadssignalpathwayinhumanpoorlydifferentiatedGCcelllineBGC-823.LocalizationofSmadproteinswasalsodeterminedusingimmunofluorescence.Then,theBGC-823cellswereculturedinthepresenceorabsenceofTGF-β1(10ng/mL)for24and48h,andtheeffectsofTGF-β1onproliferationandapoptosisweremeasuredbycellgrowthcurveandflowcytometry(FCM)analysis.TheultrastructuralfeaturesofBGC-823cellswithorwithoutTGF-β1treatmentwereobservedundertransmissionelectronmicroscope.Theapoptoticcellswerevisualizedbymeansoftheterminaldeoxynucleotidyltransferase(TdT)-mediateddTUPinsitunickend-labeling(TUNEL)method.Meanwhile,theexpressionlevelsofendogenousp15,p21andSmad7mRNAandthecorrespondingproteinsinthecellsweredetectedat1,2and3haftercultureinthepresenceorabsenceofTGF-β1(10ng/mL)bysemi-quantitativeRT-PCRandWesternblot,respectively.RESULTS:TheTGF-β1/SmadsignalingwasfoundtobeintactandfunctionalinBGC-823cells.ThegrowthcurverevealedthemostevidentinhibitionofcellproliferationbyTGF-β1at48h,andFCMassayshowedG1arrestaccompaniedwithapoptosisinducedbyTGF-β1.ThetypicalmorphologicalchangesofapoptosiswereobservedincellsexposedtoTGF-β1.Theapoptosisindex(AI)inTGF-β1-treatedcellswassignificantlyhigherthanthatintheuntreatedcontrols(10.7±1.3%vs0.32±0.06%,P＜0.01).Thelevelsofp15,p21andSmad7mRNAandcorrespondingproteinsincellsweresignificantlyup-regulatedat1h,butgraduallyreturnedtobasallevelsat3hfollowingTGF-β1(10ng/mL)treatment.CONCLUSION:TGF-β1affectsbothproliferationandapoptosisofGCcellsth