Insights into cisplatin-induced neurotoxicity and mitochondrial dysfunction in Caenorhabditis elegans

Cisplatin-induced DNA crosslinks trigger neurotoxicity in C. elegans

The anticancer drug cisplatin (CisPt) injures post-mitotic neuronal cells, leading to neuropathy. Furthermore, CisPt triggers cell death in replicating cells. Here, we aim to unravel the relevance of different types of CisPt-induced DNA lesions for evoking neurotoxicity. To this end, we comparatively analyzed wild-type and loss of function mutants of C. elegans lacking key players of specific DNA repair pathways. Deficiency in ercc-1, which is essential for nucleotide excision repair (NER) and interstrand crosslink (ICL) repair, revealed the most pronounced enhancement in CisPt-induced neurotoxicity with respect to the functionality of post-mitotic chemosensory AWA neurons, without inducing neuronal cell death. Potentiation of CisPt-triggered neurotoxicity in ercc-1 mutants was accompanied by complex alterations in both basal and CisPt-stimulated mRNA expression of genes involved in the regulation of neurotransmission, including cat-4, tph-1, mod-1, glr-1, unc-30 and eat-18. Moreover, xpf-1, csb-1, csb-1;xpc-1 and msh-6 mutants were significantly more sensitive to CisPt-induced neurotoxicity than the wild-type, whereas xpc-1, msh-2, brc-1 and dog-1 mutants did not distinguish from the wild-type. The majority of DNA repair mutants also revealed increased basal germline apoptosis, which was analyzed for control. Yet, only xpc-1, xpc-1;csb-1 and dog-1 mutants showed elevated apoptosis in the germline following CisPt treatment. To conclude, we provide evidence that neurotoxicity, including sensory neurotoxicity, is triggered by CisPt-induced DNA intra- and interstrand crosslinks that are subject of repair by NER and ICL repair. We hypothesize that especially ERCC1/XPF, CSB and MSH6-related DNA repair protects from chemotherapy-induced neuropathy in the context of CisPt-based anticancer therapy.

Prevention of anticancer therapy-induced neurotoxicity: putting DNA damage in perspective

Chemotherapy-induced peripheral neuropathy (CIPN) is a severe side effect of conventional cancer therapeutics (cAT) that significantly impacts the quality of life of tumor patients. The molecular mechanisms of CIPN are incompletely understood and there are no effective preventive or therapeutic measures available to date. Here, we present a brief overview of the current knowledge about mechanisms underlying CIPN and discuss DNA damage-related stress responses as feasible targets for the prevention of CIPN. In addition, we discuss that the nematode Caenorhabditis elegans is a useful 3R-conform model organism to further elucidate molecular mechanisms of CIPN and to identify novel lead compounds protecting from cAT-triggered neuropathy.