Tubulin / microtubules

Class

Epothilone-class microtubule-stabilizing agent (cytotoxic chemotherapy)

Pathway

Microtubule dynamics / mitotic arrest

Tubulin is the protein building block of microtubules, filament-like structures that form the cell's internal scaffolding and, during cell division, assemble into the mitotic spindle that separates chromosomes. Microtubules constantly grow and shrink, a behavior called dynamic instability, and this turnover must proceed correctly for a cell to divide successfully. Agents in the epothilone class bind to microtubules and stabilize them, preventing the normal cycles of assembly and disassembly. Cells that are actively dividing become trapped in mitosis because the spindle cannot function properly, and prolonged mitotic arrest triggers programmed cell death. Because cancer cells typically divide much faster than most normal tissues, this mechanism preferentially damages tumor cells, making microtubule stabilization a longstanding strategy in cytotoxic chemotherapy. Epothilones were developed in part to address limitations of earlier microtubule-stabilizing drugs, offering a distinct chemical scaffold that can retain activity in tumor cells that have become resistant through efflux pump mechanisms. This class is used across various solid tumors where rapid cell turnover is a defining feature, and it remains one of the core pharmacological approaches for disrupting cancer cell proliferation through direct interference with the cytoskeleton rather than DNA or specific signaling receptors.