TY - JOUR ID - 29966 TI - Roles of the Bcl-2/Bax Ratio, Caspase-8 and 9 in Resistance of Breast Cancer Cells to Paclitaxel JO - Asian Pacific Journal of Cancer Prevention JA - APJCP LA - en SN - 1513-7368 Y1 - 2014 PY - 2014 VL - 15 IS - 20 SP - 8617 EP - 8622 KW - Breast Cancer cells KW - MCF-7 KW - Paclitaxel KW - Chemoresistance KW - Bcl-2/Bax KW - Caspases DO - N2 - The goal of this study was to establish paclitaxel resistant MCF-7 cells, as in vitro model, to identify themolecular mechanisms leading to acquired chemoresistance in breast cancer cells. Resistant cells were developedby stepwise increasing exposure to paclitaxel. Gene expression levels of Bax and Bcl-2 along with protein levelsof caspase-8 and caspase-9 were evaluated in two resistant cell lines (MCF -7/Pac64 and MCF -7/Pac5 nM).Morphological modifications in paclitaxel resistance cells were examined by light microscopy and fluorescenceactivated cell sorting (FACS). As an important indicator of resistance to chemotheraputic agents, the Bcl-2/Baxratio showed a significant increase in both MCF-7/Pac5nM and MCF-7/Pac 64nM cells (p<0.001), while caspase-9levels were decreased (p<0.001) and caspase-8 was increased (p<0.001). FACS analysis demonstrated that MCF-7/Pac64 cells were smaller than MCF-7 cells with no difference in their granularity. Our results support theidea that paclitaxel induces apoptosis in a mitochondrial-dependent manner. Identifying breast cancer patientswith a higher Bcl-2/Bax ratio and caspase 9 level and then inhibiting the activity of these proteins may improvethe efficacy of chemotheraputic agents. UR - https://journal.waocp.org/article_29966.html L1 - https://journal.waocp.org/article_29966_fe468ea2fc3dca65e0607dba8e926d8f.pdf ER -