Abstract:
Objective This work aims to investigate the anticancer effect of apigenin in the MDA-MB-231 breast cancer cell line.
Methods The MDA-MB-231 cells were cultured in vitro. Cell proliferation was measured using the methyl thiazolyl tetrazolium (MTT) assay. Morphological changes in the apoptotic cells were observed by fluorescent microscopy. Flow cytometry was used to detect the rate of apoptotic cells with longer treatments of apigenin. Apoptosis-related proteins were detected by Western blot. The ribonucleic acid interference (RNAi) experiment was applied using chemically synthesized siRNA.
Results The MTT assay revealed that cell proliferation significantly decreased in a dose- and time-dependent manner. Fluorescent staining and flow cytometry showed that the number of apoptotic cells increased with a longer treatment of apigenin. Caspase 3 activation and the poly ADP ribose polymerase (PARP) cleavage were observed after treatment with apigenin, indicating the death of apoptotic cells. The upregulation of p73, PIG3, and Bax expressions, as well as the downregulation of mutant p53 and Bcl-2 expressions, was also observed in the apigenin-treated cells. The RNAi assay showed that the silencing of p73 significantly inhibited PIG3 expression, as well as the cleavage of Caspase 3 and PARP induced by the apigenin treatment.
Conclusion Apigenin exhibits an inhibitory effect against cell proliferation by inducing the p53-independent apoptosis of the MDA-MB-231 cells. The underlying mechanism may be associated with the downregulation of mutant p53, the upregulation of p73-mediated PIG3, and the increase of the Bax/Bcl-2 ratio.