Profiling the molecular and cellular consequences of microtubule drug perturbations

Abstract

Microtubules are dynamic polymers integral to cellular processes such as division, signaling, and maintenance of cell shape. Microtubule-targeting agents are crucial in the treatment of cancers, inflammatory diseases, and parasitic infections. They achieve this broad therapeutic effect by either inducing cytotoxicity or inhibiting maladaptive responses, resulting in narrow therapeutic indices that can leave patients vulnerable to toxic side effects. This dual functionality raises important questions about the factors driving their clinical efficacy. Additionally, the development of specialized microtubule-destabilizing drugs, such as those that target tumor vasculature or reduce chemotherapy-induced neutropenia, highlights the complexity of these treatments and the need for further investigation into how these clinical outcomes are achieved. This dissertation profiles molecular responses to microtubule-targeting agents and investigates whether microtubule depolymerizers, despite their diverse clinical applications, share common pathways. Using primary endothelial cells from three human donors and one immortalized cell line, I employ dose-response assays, RNA-sequencing, and phosphoproteomics to analyze the effects of these compounds. In Chapter 1, I compare transcriptional and phosphoproteomic responses that microtubule depolymerizers elicit and propose a model that links microtubule depolymerization to complex downstream cellular responses. Chapter 2 delves into specific pathways activated by microtubule polymerization and depolymerization, with a focus on their intersection with inflammatory signaling. Collectively, these findings reveal that while microtubule depolymerizers induce complex molecular responses, they do not exhibit significant differences in their mechanisms of action. This reinforces the direct link between microtubule perturbation and cellular response. Furthermore, this study also illustrates the value of multi-omics approaches in validating existing knowledge and uncovering new insights into microtubule biology.