3.3. Mode of action
Taxol and its derivatives exert anticancer activity through various mechanisms. Taxanes stabilize the microtubule assembly and prevent it from de-assembling, thus preventing normal metaphase spindle configuration of chromosomes. As a result, the progression of mitosis blocks and prolonged activation of mitosis checkpoint leads to apoptosis or reversion of the cancer cell to the GO phase. It is also involved in the stimulation of apoptotic cascades by upregulating Fas/FasL and Bax, and downregulating Bcl-2 leading to the activation of caspase-3, -8, and -9 in MG-63, U-2OS, Saos-2, and MNNG/HOS human osteosarcoma cells (Liang et al., 2012). The reduction of Bcl-2/Bax protein and mRNA levels leads to cell cycle arrest in cancer cells (Fig. 6 ).