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The Mode of Action of Taxol: Apoptosis at Low Concentration and Necrosis at High Concentration
- Source :
- Biochemical and Biophysical Research Communications. 263:398-404
- Publication Year :
- 1999
- Publisher :
- Elsevier BV, 1999.
-
Abstract
- The cytotoxicity of Taxol represents both inhibition of cell proliferation and cell death. The drug blocked cells in the G2/M phase of the cell cycle. It has also been reported that Taxol induced cell apoptosis; however, the mode of action of Taxol is far from clear. In this communication, the cytotoxicity of Taxol in various breast cancer cell lines was carefully examined. We showed that Taxol treatment induced a biphasic decrease of viable cells. While the first phase of decrease occurred over concentrations ranging from 0.005 to 0.05 microM and the second phase of decrease occurred at concentrations ranging from 5 to 50 microM, there was a plateau between these ranges. We determined that the biphasic response was due to two different mechanisms. In the lower concentration range (0.005-0.05 microM), Taxol stabilized the spindle during mitosis, thereby blocking mitosis. This mitotic block led to the inhibition of cell proliferation and the induction of apoptosis. In the higher concentration range (5-50 microM), Taxol mainly increased the polymerization of microtubule and stimulated the formation of microtubule bundles, which blocked entry into S phase. This inhibition of S phase entry led to the inhibition of cell proliferation and the induction of necrosis. These findings may have profound clinical implications.
- Subjects :
- Programmed cell death
Necrosis
Paclitaxel
Biophysics
Mitosis
Apoptosis
Breast Neoplasms
Spindle Apparatus
Biology
Microtubules
Biochemistry
chemistry.chemical_compound
Tumor Cells, Cultured
medicine
Humans
Cytotoxicity
Molecular Biology
Dose-Response Relationship, Drug
Cell growth
Cell Biology
Cell cycle
Cell biology
chemistry
Female
medicine.symptom
Subjects
Details
- ISSN :
- 0006291X
- Volume :
- 263
- Database :
- OpenAIRE
- Journal :
- Biochemical and Biophysical Research Communications
- Accession number :
- edsair.doi.dedup.....f91a8026998a6817236126dfe0ff7ea3