Apoptosis resistant HOMUR cells exhibit reduced PARP cleavage when treated with DCA. HCT116, HOMUR 7, HOMUR 11, or HOMUR 17 cells were plated onto 10 cm plates and allowed to attach for 48 hours. Cells were either untreated (-) or incubated with 500 micromolar DCA (+) and sample plates harvested at the indicated time intervals. Total cell proteins were extracted, fractionated by SDS-PAGE, and protein blots probed with antibodies against PARP. Alpha tubulin was used to control for loading variations. These experiments were repeated twice. Representative immunoblots are depicted.