M344 induces ATF3 and enhances its expression in combination with cisplatin treatment. A, ATF3 protein expression levels following 24 hr treatment with control, DMSO vehicle, and, low and high doses of M344 (1 and 5 μM) in MCF-7, PC3, SK-OV3 and A549 cell lines. B, ATF3 protein expression levels following 24 hrs treatment with cisplatin (10 μg/ml), or cisplatin in combination with M344 (1 and 5 μM) in MCF-7 and SKOV-3 cell lines. In all blots actin is used as a loading control. C, ATF3 mRNA quantified by quantitative RT-PCR of MCF-7 cells comparing untreated treated control, DMSO vehicle, M344 (1 and 5 μM), cisplatin (10 μg/ml), or cisplatin in combination with M344 (5 μM) for 24 hrs. Error bars are representative of quantified mRNA from three independent experiments normalized to GAPDH expression.