Tylophorine Abrogates G2/M Arrest Induced by Doxorubicine and Promotes Increased Apoptosis in T47D Breast Cancer Cells

BACKGROUND: The effects of tylophorine, a natural alkaloid found in Tylophora indica, administered as a single compound or in combination with doxorubicin on cell cycling and apoptosis were assessed in T47D breast cancer cells, selected as a model system for breast cancer. METHODS: Cell cycle distribution and apoptosis were examined by flow cytometry. Caspase 3 and 9 expression was determined by immunocytochemistry. RESULT: We found that tylophorine did not significantly influence the cell cycle distribution of T47D cells. However, the alkaloid did prevent accumulation of cells in the G2/M phase. In addition, tylophorine increased the number of apoptotic cells. Expression of proapoptotic proteins (caspases 3 and 9) was up-regulated upon administration of tyloporine alone or in combination with doxorubicin. CONCLUSIONS: Tylophorine alone or in combination with doxorubicin induced apoptosis in T47D breast cancer cells through modulation of the cell cycle and affecting the expression of caspases 3 and 9.