Objective:Todeterminewhetherpyrrolidinedithio-carbamate(PDTC)enhancesTNFα-inducedapoptosisinculturedbreastcancercellsandexploretheroleofNF-κBinTNFα-inducedapoptosis.Methods:HumanbreastcancercelllinesMCF-7andMDA-MB-435sweretreatedwithTNFα,PDTCandcombinationtherapy.CellsurvivalsweredeterminedbyMTTassay.ApoptosiswasdetectedbyTUNELandflowcytometry.NF-κBDNAbindingactivitywasdetectedusingelectrophoresismobilityshiftassay(EMSA).WesternblotswereperformedtodemonstrateIκBα(InhibitorproteinofnuclearfactorκB)phosphorylationanddegradation.Results:CellgrowthwasnotsuppressedbyeitherTNFα(2000U/mlorless)orPDTCalone.BothcelllinestreatedwithTNFα(2000U/ml)combinedwithPDTC(50μmol/L)showedsignificantgrowthinhibition.PDTCinhibitedTNFα-inducedIκBαphosphorylationanddegradationinbothcelllines.EMSAshowedthatPDTCcontinuouslyinhibitedTNFαinducedNF-κBDNAbindingactivity.TNFαinducedapoptosis(TUNEL)wasincreasedsignificantlywhenbothcellswerepretreatedwithPDTC,andthiswasconfirmedbyFlowcytometry.Conclusion:PDTCenhancesTNFα-inducedapoptosisviainhibitingIκBαphosphorylationanddegradationinhumanbreastcancercells.NF-κBprotectsagainstTNFα-inducedapoptosis.
