|dc.description.abstract||Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting, debilitating, and common side effect of multiple classes of antineoplastic drugs that are used as first-line therapies for cancer. Yet, the mechanisms underlying CIPN remain poorly understood. Among the drugs associated with CIPN are antimitotic agents that target microtubules and either promote or prevent their depolymerization. Unfortunately, extensive research using animal models has yet to reveal why some patients develop neuropathy and others do not. Previous work in which human cortical neurons were treated with paclitaxel has laid the groundwork for studying CIPN in peripheral human iPSC-derived neurons. Using multiple cell lines, we sought to identify how patient genetics contribute to the development of CIPN.
We developed a model for studying dynamic changes in human iPSC-derived motor neurons following treatment with a microtubule-stabilizing agent (paclitaxel) as well as a microtubule-destabilizing agent (vincristine). We first focused on validating chemotherapy-associated phenotypic changes in motor neurons using high-throughput, automated analysis. We observed a dose-dependent decrease in neurite length in response to treatment, an established marker for CIPN development. To investigate whether this result was due to defects in outgrowth or active retraction, we optimized a spot culture format. Notably, we found that both paclitaxel and vincristine cause neurite retraction, supporting the hypothesis that paclitaxel-induced neuropathy is a dying back neuropathy and also suggesting a role for organized neurite retraction in disease pathogenesis.
Our model allows for the study of distal axon morphology and terminal arbor degeneration in CIPN. Moreover, it allows researchers to view neuron growth and regeneration as the dynamic processes that they are. Ultimately, we anticipate that this work will provide the basis for understanding the mechanisms of CIPN, improving human-cell screening methods for therapeutics, and furthering research on other neurodegenerative diseases.||