ANTIPROLIFERATIVE EFFECT OF CALOTROPIS GIGANTEA (L.) R. BR. ON BREAST CANCER CELLS MCF-7

The investigation was aimed at evaluation of the mechanism of anticancer activity of the glycosides from Calotropis gigantea on breast cancer MCF-7 cells through analysis of modulation of gene expression. Cardiac glycosides were isolated from the leaves of C. gigantea, and the compounds were identified through LC-MS. Influence of the glycoside sample on the expression of p53 and Bcl-2 genes in MCF-7 cells was assessed by comparative RT-PCR of MCF-7 cells treated with the test sample, standard drug, and control followed by validation through colony formation assay. Presence of calactin, calotropin, asceplin, and cymarin along with 4 other unidentified compounds has been detected in the glycoside fraction isolated from the leaf sample of C. gigantea. Influence of the glycosides on the modulation of the expression of tumor suppressor gene p53 indicated a weak down-regulation of its expression, whereas on the modulation of Bcl-2 was found to be drastic with almost absolute inhibition of its expression. Results of the study suggest that cardiac glycosides cast a dual influence on MCF-7 cells, namely cytotoxic effect through down-regulation of p53 gene expression and antiproliferative effect through down-regulation of Bcl-2 gene expression of which latter is more effective.