Inhibition of PKCδ reduces cisplatin-induced nephrotoxicity without blocking chemotherapeutic efficacy in mouse models of cancer
Navjotsingh Pabla, … , Robert O. Messing, Zheng Dong
Navjotsingh Pabla, … , Robert O. Messing, Zheng Dong
Published June 1, 2011
Citation Information: J Clin Invest. 2011;121(7):2709-2722. https://doi.org/10.1172/JCI45586.
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Inhibition of PKCδ reduces cisplatin-induced nephrotoxicity without blocking chemotherapeutic efficacy in mouse models of cancer

Abstract

Cisplatin is a widely used cancer therapy drug that unfortunately has major side effects in normal tissues, notably nephrotoxicity in kidneys. Despite intensive research, the mechanism of cisplatin-induced nephrotoxicity remains unclear, and renoprotective approaches during cisplatin-based chemotherapy are lacking. Here we have identified PKCδ as a critical regulator of cisplatin nephrotoxicity, which can be effectively targeted for renoprotection during chemotherapy. We showed that early during cisplatin nephrotoxicity, Src interacted with, phosphorylated, and activated PKCδ in mouse kidney lysates. After activation, PKCδ regulated MAPKs, but not p53, to induce renal cell apoptosis. Thus, inhibition of PKCδ pharmacologically or genetically attenuated kidney cell apoptosis and tissue damage, preserving renal function during cisplatin treatment. Conversely, inhibition of PKCδ enhanced cisplatin-induced cell death in multiple cancer cell lines and, remarkably, enhanced the chemotherapeutic effects of cisplatin in several xenograft and syngeneic mouse tumor models while protecting kidneys from nephrotoxicity. Together these results demonstrate a role of PKCδ in cisplatin nephrotoxicity and support targeting PKCδ as an effective strategy for renoprotection during cisplatin-based cancer therapy.

Authors

Navjotsingh Pabla, Guie Dong, Man Jiang, Shuang Huang, M. Vijay Kumar, Robert O. Messing, Zheng Dong

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Figure 1

PKC-δ activation during cisplatin treatment in mice and RPTCs.

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PKC-δ activation during cisplatin treatment in mice and RPTCs. (A) Kinas...
(A) Kinase assay of PKCδ activity in kidney tissues. Male C57BL/6 mice of 8 to 10 weeks of age were injected with 30 mg/kg cisplatin before collection of renal tissues at day 0–3. PKCδ was immunoprecipitated from tissue lysate and in vitro kinase reaction with the substrate histone H1 and [γ-32P]ATP. Histone H1 phosphorylation was analyzed by SDS-PAGE and autoradiography to indicate kinase activity. (B) PKCδ phosphorylation at tyr-311 in kidney tissues. Kidney tissue lysate was analyzed by immunoblot analysis for phosphorylated (tyr-311) PKCδ (p-PKCδ), total PKCδ, or β-actin. (C) Tyrosine phosphorylation of PKCδ during cisplatin treatment in vivo. PKCδ was immunoprecipitated from control and cisplatin-treated renal tissues for immunoblot analysis of phosphotyrosine (pY). (D) PKCδ (tyr-311) phosphorylation during cisplatin treatment in vitro. RPTCs were treated with 20 μM cisplatin for 0 to 4 hours to collect whole cell lysates for immunoblot analysis of total and phosphorylated (tyr-311) PKCδ. (E) In vitro kinase assay of PKCδ activation in RPTCs. RPTCs were treated with 20 μM cisplatin for 0 to 16 hours to collect whole cell lysates for PKCδ immunoprecipitation and kinase activity assay. (F) Translocation of PKCδ during cisplatin treatment. RPTCs were treated with cisplatin for 0 to 1 hours and then fractionated into nuclear, membrane, and cytosolic fractions for immunoblot analysis of PKCδ. Mean ± SD, n = 4. *P < 0.001 versus control.