Roles of p53 and Caspases in Induction of Apoptosis in MCF-7 Breast Cancer Cells Treated with a Methanolic Extract of Nigella Sativa Seeds

Background: Nigella Sativa (NS) is an herb from the Ranunculaceae family that exhibits numerous medicinalproperties and has been used as important constituent of many complementary and alternative medicines (CAMs).The ability of NS to kill cancer cells such as PC3, HeLa and hepatoma cells is well established. However, ourunderstanding of the mode of death caused by NS remains nebulous. The objective of this study was to gainfurther insight into the mode and mechanism of death caused by NS in breast cancer MCF-7 cells. Materialsand
Methods: Human breast cancer cells (MCF-7) were treated with a methanolic extract of NS, and a dose- andtime-dependent study was performed. The IC50 was calculated using a Cell Titer Blue® viability assay assay, andevidence for DNA fragmentation was obtained by fluorescence microscopy TUNEL assay. Gene expression wasalso profiled for a number of apoptosis-related genes (Caspase-3, -8, -9 and p53 genes) through qPCR.
Results:The IC50 of MCF-7 cells was 62.8μL/mL. When MCF-7 cells were exposed to 50 μL/mL and 100 μL/mL NS for24h, 48h and 72h, microscopic examination (TUNEL assay) revealed a dose- and time-dependent increase inapoptosis. Similarly, the expression of the Caspase-3, -8, -9 and p53 genes increased significantly according to thedose and time.
Conclusions: NS induced apoptosis in MCF-7 cells through both the p53 and caspase pathways.NS could potentially represent an alternative source of medicine for breast cancer therapy.