The pivotal role of NCX inhibitors in neuroprotection against Oxaliplatin-induced peripheral neurotoxicity

Oxaliplatin (OHP) is a cornerstone in colorectal cancer treatment but its clinical use is limited by OHP-induced peripheral neurotoxicity (OIPN), which includes an acute and a chronic form. Acute OIPN manifests early as transient axonal hyperexcitability caused by functional alterations of voltage-gated sodium channels (NaV). Chronic OIPN presents as a persistent sensory neuronopathy characterized by axonal damage (AxD). These two conditions may be mechanistically linked: NaV dysfunction increases intracellular Na⁺ levels, potentially activating the Sodium–Calcium Exchanger (NCX) in reverse-mode. This results in Ca²⁺ influx, leading to toxic accumulation and axonal degeneration. The present study investigated the role of NCX in AxD using an in vitro OIPN model. Dorsal root ganglia primary neuronal cultures (male C57BL/6 mice) were analyzed using the Nanolive CX-A 3D holotomographic microscope for live-cell imaging. We tested potential neuroprotective strategies, including SEA0400, a potent NCX inhibitor, and siRNAs targeting NCX2, the most highly expressed neuronal isoform. Exposure to OHP (7.5–25µM, 48h) induced significant neurotoxicity, evidenced by neurite fragmentation and reduced cell viability, preceded by autophagic stress and necroptosis in a dose/time-dependent manner. SEA0400 (1µM, 3h pre-treatment) effectively mitigated these pathological changes. Moreover, OHP induced alterations were more strongly prevented by downregulating NCX2 expression via siRNAs (5nM, 24h pre treatment). Overall, our findings show that OIPN related AxD can be prevented by targeting NCX family—particularly NCX2—highlighting promising therapeutic avenues for AxD prevention. Notably, this mechanism may be relevant beyond OIPN, as axonal hyperexcitability and NCX mediated Ca²⁺ toxicity have also been implicated in genetic, inflammatory, and metabolic neuropathies.