Paclitaxel impairs mitochondrial dynamics in human sensory-like neuron cells

Taxanes are considered first-line chemotherapeutic agents to treat solid cancer. Paclitaxel (PTX) is a commonly used taxane and although effective, it induces peripheral chronic neuropathy in around 60-70% of patients. Studies have demonstrated a correlation between impairment in bioenergetic metabolism and the development of neuropathies. However, the correlation between mitochondrial fusion-fission processes in sensory neurons and the development of neurodegeneration and pain remains poorly understood. Considering that neurons have a high metabolic demand and numerous mitochondria, and that chemotherapy-induced neuropathy is often accompanied by mitochondrial dysfunction, we investigated the role of mitochondrial plasticity in sensory-like neuron cells incubated with paclitaxel. Our findings indicate that neurotoxic concentrations of paclitaxel induce mitochondrial fragmentation by downregulating fusion proteins, such as mitofusin-1 and - 2 (MFN1 and MFN2), and upregulating fission proteins, such as dynamin-related protein 1 (Drp1). Also, paclitaxel increases superoxide release, impairs neuritogenesis, and activates pro-nociceptive signaling, measured by activating transcription factor 3 (ATF-3) expression, substance P release, and prostaglandin E2 (PGE2) - induced calcium influx. Of note, blocking excessive fission with P110, a pharmacological inhibitor of Drp1, PTX-induced cytotoxicity was prevented in sensory neuron-like cells. Together, our data suggest that impairment in mitochondrial dynamics of sensory neurons contributes to paclitaxel neurotoxicity and, consequently, to nociception. Therefore, preventing mitochondrial fission may be a strategy to prevent PTX-induced neurotoxicity, opening a new perspective to understanding the mechanisms involved in the development of PTX-induced neuropathy.