Taxol induces caspase-10-dependent apoptosis.

Taxol (paclitaxel) is known to inhibit cell growth and trigger significant apoptosis in various cancer cells. Although taxol induces apoptosis of cancer cells, its exact mechanism of action is not yet known. In this study we investigated death receptors, FAS-associated death domain protein (FADD), the activation of caspases-10 and -8 as well as the downstream caspases, and reactive oxygen species (ROS) in taxol-induced apoptosis in the CCRF-HSB-2 human lymphoblastic leukemia cell line.

A P-glycoprotein- and MRP1-independent doxorubicin-resistant variant of the MCF-7 breast cancer cell line with defects in caspase-6, -7, -8, -9 and -10 activation pathways.

Background: Several mechanisms are known to cause resistance to chemotherapy in cancer cells, but the mechanisms of drug resistance due to a lack of apoptosis are not well elucidated.

Materials And Methods: To understand the mechanisms of resistance to apoptosis induced by doxorubicin (DOX), we developed a DOX-resistant variant of MCF-7 referred to as MCF-7/Adr-20, measured growth inhibition by methylene blue cell survival assay, quantitated apoptosis by annexin V binding assay and detected activation of caspases-6, -7, -8, -9 and -10 in these cells.

Results: The resistant cells expressed 20-fold resistance to apoptosis induced by DOX compared to MCF-7 cells.