Genetic Reduction of Mitochondria Complex I Subunits is Protective against Cisplatin-Induced Neurotoxicity in Drosophila.

Abstract

Chemotherapy-induced peripheral neuropathy (CIPN) is a prevalent side effect of widely used platinum-based anticancer agents. There are few predictable risk factors with which to identify susceptible patients. Effective preventive measures or treatments are not available. Here, we have used a model of CIPN in Drosophila melanogaster to identify genetic changes that confer resistance to cisplatin-induced neuronal damage but not in the rapidly dividing cells of the ovary. The Drosophila strain attP40, used as a genetic background for the creation of RNAi lines, is resistant to cisplatin damage compared with the similar attP2 background strain. attP40 flies have reduced mRNA expression of ND-13A, a component of the mitochondria electron transport chain complex I. Reduction of ND-13A via neuron-specific RNAi leads to resistance to the dose-dependent climbing deficiencies and neuronal apoptosis observed in control flies. These flies are also resistant to acute oxidative stress, suggesting a mechanism for resistance to cisplatin. The mitochondria of attP40 flies function similarly to control attP2 mitochondria under normal conditions. Mitochondria are damaged by cisplatin, leading to reduced activity, but attP40 mitochondria are able to retain function and even increase basal respiration rates in response to this stress. This retained mitochondrial activity is likely mediated by Sirt1 and peroxisome proliferator-activated receptor gamma coactivator-1α, and is key to cisplatin resistance. Our findings represent the potential for both identification of susceptible patients and prevention of CIPN through the targeting of mitochondria.SIGNIFICANCE STATEMENT Chemotherapy-induced peripheral neuropathy is a major, debilitating side effect of many platinum-based cancer drugs. There are few available screening tools to identify patients at risk, and there are no effective treatments. Here, we report a novel genetic change that confers resistance to cisplatin-induced neurotoxicity in a Drosophila model while preserving the toxic effect in rapidly dividing cells. This work has the potential to influence patient susceptibility testing and development of novel CIPN preventive treatments.