Cisplatin-Induced Renal Cell Apoptosis: Caspase 3-Dependent and -Independent Pathways

Abstract

The chemotherapeutic cisplatin causes renal dysfunction and renal proximal tubular cell (RPTC) apoptosis. The goal of these studies was to examine the role of p53, caspase 3, 8, and 9, and mitochondria in the signaling of cisplatin-induced apoptosis. Cisplatin (50 M) produced time-dependent apoptosis in RPTCs, causing cell shrinkage, a 50-fold increase in caspase 3 activity, a 4-fold increase in phosphatidylserine externalization, and 5-and 15-fold increases in chromatin condensation and DNA hypoploidy, respectively. Mitochondrial membrane potential and ATP levels did not change at any time during cisplatin exposure. Caspase 8 and 9 activities also did not increase during treatment. Cisplatin increased nuclear p53 expression 4 h after treatment, preceding both caspase 3 activation and chromatin condensation.Treatment with the p53 inhibitor ␣-2-(2-imino-4,5,6,7-tetrahydrobenzothiazol-3-yl)-1-p-tolylethanone (PFT) before cisplatin exposure inhibited p53 nuclear expression at 4, 8, and 12 h and inhibited phosphatidylserine externalization and caspase 3 activation at 12 h. Neither DEVD-fmk nor ZVAD-fmk inhibited cisplatininduced p53 nuclear expression. Both DEVD-fmk and ZVAD-fmk completely inhibited caspase 3 activity but, like PFT, partially inhibited cisplatin-induced chromatin condensation, annexin V labeling, and DNA hypoploidy after 24 h. These data demonstrate that at least 50% of cisplatin-induced apoptosis in RPTC is mediated by p53 and that p53 activates caspase 3 independently of either caspase 9 or 8 or mitochondrial dysfunction. Furthermore, 50% of cisplatin-induced RPTC apoptosis is independent of p53 and caspases 3, 8, and 9.

Transcriptional activation of caspase-6 and -7 genes by cisplatin-induced p53 and its functional significance in cisplatin nephrotoxicity

“…Several studies including ours have previously demonstrated activation of executioner caspases (caspase-3/7 and -6) in both in vitro 12,13 and in vivo 14,15 models of cisplatin-induced AKI. Similarly, induction of p53 transcription factor was demonstrated in RTECs in both in vitro [16][17][18] and in vivo 19 studies of cisplatin AKI. Inhibiting the activation of p53 protein by pifithrin-a, a pharmacological inhibitor of p53, blocked caspase activation.…”

“…Inhibiting the activation of p53 protein by pifithrin-a, a pharmacological inhibitor of p53, blocked caspase activation. [16][17][18] One of the mechanisms whereby p53 can control caspase activation is by direct transcriptional regulation of their expression. However, transcriptional control of caspases and the functional significance of this regulation are not known in renal injury.…”

Suppression of heat shock protein 70 by siRNA enhances the antitumor effects of cisplatin in cultured human osteosarcoma cells

“…To evaluate whether Hsp70 siRNA can inhibit Hsp70 protein expression during treatment with cisplatin, MG63 cells were first transfected with Hsp70 siRNA for 48 h, following which they were treated with 50 μM cisplatin for 48 h. The dosage of cisplatin (50 μM) was selected as a high-dose administration example (Cummings et al 2002;Liu et al 2014b). The effect of Hsp70 siRNA transfection of MG63 cells on cisplatin induction of Hsp70 expression was then analyzed using Western blotting and real-time RT-PCR.…”

Substituted titanocenes induce caspase-dependent apoptosis in human epidermoid carcinoma cells in vitro and exhibit antitumour activity in vivo

“…Cisplatin has been shown to induce apoptotic cell death in human cancer cells, including A431 cells (Gonzalez et al, 2001;Cummings and Schnellmann, 2002;Sawada et al, 2003). To investigate the mechanism by which Titanocene Y induces cell death, A431 cancer cells were stained with Annexin V and propidium iodide to detect early and late apoptotic cells.…”