ERK1/2/p53 and NF-κB dependent-PUMA activation involves in doxorubicin-induced cardiomyocyte apoptosis.

OBJECTIVE: Numerous studies have demonstrated that Doxorubicin (DOX) induces cardiomyocyte apoptosis, which is associated with DOX-induced acute and chronic cardiotoxicity. DOX activated ERP1/2 and NF-KB signals has been linked to DOX-induced apoptosis and cardiotoxicity. However, the underlying mechanisms responsible for DOX-induced apoptosis have not been completely elucidated. In this study, we determine whether both ERK1/2/p53-dependent and NF-κB dependent-PUMA activation was related to DOX-induced apoptosis in H9c2 cells.

MATERIALS AND METHODS: H9c2 cells were treated with DOX (1 μM) for 2-48 hours. To explore the effect of ERK1/2, NF-KB, P53 and PUMA on DOX-induced apoptosis in H9c2 cells, H9c2 cells were transfected with PUMA siRNA or p65 siRNA, or treated with PFT-α (a chemical inhibitor of p53), or PD98059 (ERK inhibitor) before DOX treatment. MTT, Flow cytometry, TUNEL, Western blot and EMSA assay was used to detect cell survival, apoptosis, protein expression and NF-KB activity.

RESULTS: DOX induced apoptosis and inhibited growth of H9c2 cells in a time-dependent manner. DOX activated ERK1/2, NF-KB, p53 and PUMA. Knockdown of PUMA completely blocked DOX-induced cell apoptosis and survival inhibition. Knockdown of NF-KB or ERK1/2 alone could partly block DOX-induced PUMA upregulation and cell apoptosis. However, knockdown of NF-KB and ERK1/2 together completely blocked DOX-induced cell apoptosis and PUMA upregulation. In addition, knockdown of ERK1/2 blocked p53-dependent PUMA upregulation.

CONCLUSIONS: DOX induced apoptosis and inhibited growth of H9c2 cells by activation of ERK1/2/p53 and NF-κB dependent-PUMA signaling pathway.