Microtubule inhibitors

Question 1

Vincristine, vinblastine

Answer 1

Alkaloids that bind to tubulin in M-phase and block polymerization of microtubules so that mitotic spindles cannot form.
use: Hodgkin’s lymphoma, Wilm’s tumor, choriocarcinoma, ALL
toxicity: Vincristine - neurotoxicity (areflexia, peripheral neuritis), paralytic ileus
vinblastine - bone marrow suppression

Question 2

Paclitaxel, other taxols

Answer 2

hyperstabilize polymerized microtubules in M-phase so that mitotic spindle cannot break down (anaphase cannot occur)
Use: ovarian and breast carcinomas
Toxicity: myelosuppresion and hypersensitivity