Which of the following is a mechanism of action for both vinca alkaloids and taxanes?

The mechanism of action for both vinca alkaloids and taxanes involves interference with mitotic spindle assembly, which is critical for proper cell division during mitosis.

Vinca alkaloids, such as vincristine and vinblastine, work by preventing the formation of microtubules, which are necessary for the construction of the spindle apparatus. By stopping the assembly of the spindle, these drugs effectively halt mitosis, leading to cell cycle arrest and apoptosis in rapidly dividing cancer cells.

Taxanes, including paclitaxel and docetaxel, operate differently in that they promote the stabilization of microtubules, preventing their disassembly. This abnormal stabilization causes a failure in the normal functioning of the mitotic spindle, leading to improper separation of chromosomes during mitosis. The resulting cell cycle arrest and subsequent apoptotic signals contribute to their efficacy as chemotherapy agents.

Thus, the correct answer highlights the shared outcome of both drug classes—disruption of spindle formation—which is crucial for targeting cancer cell division.