Transient Receptor Potential Channels in Chemotherapy-Induced Neuropathy

Chemotherapy-Induced Peripheral Neuropathy (CIPN) is a common dose-limiting side effect of many chemotherapeuticdrugs, including platinum-based compounds (e.g., cisplatin and oxaliplatin), taxanes (e.g., paclitaxel), vinca alkaloids (e.g., vincristine), and the first-in-class proteasome inhibitor, bortezomib. Among the various sensory symptoms of CIPN, paresthesia, dysesthesia, spontaneous pain, and mechanical and thermal hypersensitivity are prominent. Inflammation, oxidative stress, loss of intraepidermal nerve fibers, modifications of mitochondria, and various ion channels alterations are part of the several mechanisms contributing to CIPN. Because attempts to mitigate chemotherapeutic- induced acute neuronal hyperexcitability and the subsequent peripheral neuropathy have yielded unsatisfactory results, a more in-depth understanding of the mechanism(s) responsible for the neurotoxic action of anticancer drugs is required. Some members of the transient receptor potential (TRP) family of channels, as the TRPV1 and TRPV4 (vanilloid), TRPA1 (ankyrin) and TRPM8 (melastatin) are expressed on the plasma membrane of primary sensory neurons (nociceptors), where they are activated by an unprecedented series of physical and chemical stimuli. There is evidence that TRPV1, TRPV4, TRPA1 and TRPM8 are prominent contributors of mechanical and thermal hypersensitivity in models of CIPN. In particular, in vitro and in vivo studies have pointed out the unique role of TRPA1 and oxidative stress in the mechanism responsible for cold and mechanical hyperalgesia in rodent models of CIPN.