Anticancer Effects of Calotropis procera Latex Extract in MCF-7 Breast Cancer Cells

Background: Calotropis procera is a wild growing medicinal plant with many pharmacological properties, arising mainly from its latex, which contains many biologically active compounds, including cardiac glycosides. Objectives: The present study was conducted to isolate a cardiac glycosidal (CG) extract from the latex of C. procera and to assess its potential in inducing anticancer effects on breast cancer cells (MCF-7). Materials and Methods: Cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and morphological changes observations. The generation of intracellular reactive oxygen species (ROS) was evaluated both qualitatively and quantitatively. Flow cytometry technique was used to evaluate apoptosis and autophagy was determined by fluorescence microscopy and Western blotting. Results: The extract significantly (P < 0.05) inhibited the proliferation of MCF-7 cells and that this effect increased in line with concentration. Systemic changes in the morphology of treated cells when compared with control cells were observed. ROS levels were increased by about 1.5 and 1.95-fold at the highest concentration of 75 mu g/ml after 12 and 24 h of treatment, respectively. A significant (P < 0.05) increase in the percentage of early and late apoptotic cells were recorded. Autophagy induction in treated MCF-7 was confirmed with the presence of acidic vesicular organelles. Finally, the change in the intracellular localization of light chain 3 (LC3) protein was determined by Western blotting using primary antibodies. A maximum of a 1.76-fold increase was observed in the expression level of the LC3 marker protein. Conclusion: These findings suggest that CG extract increased the levels of intracellular ROS resulting in the induction of cytotoxicity, apoptosis, and autophagy in MCF-7 cells.