cp-31398 and Carcinoma

p53 is considered the guardian of the genome and has a number of biological functions, including cell cycle arrest, DNA repair, and apoptosis. In a recent study by Foster and colleagues, the pharmacological compound CP-31398 was found to stabilize wild-type p53 to enhance its transcriptional activity and inhibit tumor growth in mice. We hypothesize that CP-31398 induces apoptosis by stabilizing the p53 protein and activating the mitochondrial-mediated pathway. Using the wild-type p53 HCT116+/+ and the p53-deficient HCT116-/- colon carcinoma cell lines, we demonstrate here that CP-31398 induces apoptosis in a dose-, time-, and p53-dependent manner. CP-31398 dramatically elevated p53 and p21(Waf1) protein levels in HCT116+/+, while a smaller p53-independent p21(Waf1) induction by CP-31398 in HCT116-/- cells was also observed. Moreover, we also found that CP-31398 increased Bax expression, altered mitochondrial membrane potential causing the release of cytochrome c, and induced the cleavage of caspases-9 and -3. Taken together, our results indicate that CP-31398 induces p53-dependent apoptosis by activating the Bax/mitochondrial/caspase-9 pathway. Elucidating the mechanism by which CP-31398 induces cell death may establish it as an anticancer agent.

Topics: Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Carcinoma; Caspase 3; Caspase 9; Caspases; Cell Division; Cell Transformation, Neoplastic; Colonic Neoplasms; Cytochrome c Group; Eukaryotic Cells; Humans; Membrane Potentials; Mitochondria; Neoplasms; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Pyrimidines; Tumor Cells, Cultured; Tumor Suppressor Protein p53