Research Institute for Molecular Pharmacology and Therapeutics, Central South University, Changsha, Hunan 410083, People's Republic of China.
The apoptotic effects of natural (n-) and synthetic (s-) DADS (diallyl disulfide; 3,3'-thiobisprop-1-ene) on human breast-cancer MCF-7 cells were investigated in vitro. 5-Fu (5-fluorouracil) and CTX (cyclophosphamide; Cytoxan) were used as comparative control anticancer agents. After MCF-7 cells had been treated with the drugs, cell viability, morphological change, apoptosis and changes in the cell cycle were measured. The results indicated that s- and n-DADS had similar cytotoxicities towards human breast-cancer MCF-7 cells and showed dose-dependent and time-dependent inhibitory effects. Morphological observations and flow-cytometric results showed that the four drugs (s-DADS, n-DADS, CTX and 5-Fu) induced apoptosis in MCF-7 cells to different extents. The apoptotic effects of s- and n-DADS were superior to those of 5-Fu and CTX.