Abstract
Background: Curcumin is a major component of Curcuma longa rhizome and has been used as a traditional medicine for centuries. In this study, we showed that curcumin induced cell cycle arrest followed by antiproliferation and apoptosis in human osteosarcoma (HOS) cells. Materials and Methods: Antiproliferative activity was measured with the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Nuclear fragmentation was observed with a fluorescence microscope. Flow cytometry was performed to observe cell cycle distribution and apoptotic body appearance. Changes in cell cycle regulatory and apoptosis-related proteins were investigated by Western blot analysis. Results: The IC50 value of curcumin was ~4.0 μg/ml. Induction of apoptosis was evidenced by apoptotic body appearance and chromosomal DNA degradation. Flow-cytometric analysis indicated that curcumin induced successive G1/S and G2/M phase arrest followed by apoptosis in HOS cells. The G1/S and G2/S phase arrest was accompanied by down-regulation of cyclin D1, cdc2 and cyclin B1, respectively. Apoptosis was induced by capspase-3 activation and poly(ADP-ribosyl)polymerase (PARP) cleavage. Conclusion: Our results demonstrated that curcumin caused death of HOS cells by blocking cells successively in G1/S and G2/M phases and activating the caspase-3 pathway.
- Received July 13, 2009.
- Revision received November 11, 2009.
- Accepted November 12, 2009.
- Copyright© 2009 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved