30 out of 100
Paclitaxel acts by (DNB June 2011)
|B||Inhibition of Microtubule formation|
|C||Mitotic cell inhibitor|
|D||Exaggerates polymerization and causes the stabilization of the microtubules|
Ans. D Exaggerates polymerization and causes the stabilization of the microtubules
- It is a complex diterpine taxane obtained from bark of the Western yew tree, which exerts cytotoxic action by a novel mechanism.
- It enhances polymerization of tubulin: a mechanism opposite to that of vinca alkaloids.
- The microtubules are stabilized and their depolymerization is prevented.
- This stability results in inhibition of normal dynamic reorganization of the microtubule network that is essential for vital interphase and mitotic functions.
- Abnormal arrays or ‘bundles’ of microtubules are produced throughout the cell cycle.
- Cytotoxic action of paclitaxel emphasizes the importance of tubulin microtubule dynamic equilibrium.
- The approved indications of paclitaxel are metastatic ovarian and breast carcinoma after failure of first line chemotherapy and relapse cases.
- It has also shown efficacy in advanced cases of head and neck cancer, small cell lung cancer, esophageal adenocarcinoma and hormone refractory prostate cancer.