Abstract
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Compelling evidence from epidemiological and experimental studies indicate that the disruption of circadian rhythm and decreased melatonin synthesis are risk factors for breast cancer. With the ever-increasing rate of breast cancer cases globally, there is a strong need for safer, effective, and alternate treatment strategies with lesser side effects. This study aimed to investigate the effects of melatonin and vitamin D3 on the gene expression of two apoptotic factors, BCL-2 and Bax, in the MCF-7 cancer cell line.
Cell viability (MCF-7) was studied through MTT reduction assay in response to melatonin (1 nM, 5 nM and 10 nM) and vitamin D3 (0.5 nM, 1 nM and 10 NM). The optimum dose of melatonin (5 nM) and vitamin D3 (0.5 nM) were selected for their combination and Bax/BCL-2 ratio determination. Changes on the expression of genes BCL-2 and Bax, were determined through mRNA expression while Western blot analysis was used to detect changes in the expression of BCL-2 and Bax at the protein level.
There was an upregulation of Bax gene expression and protein expression with the treatments of melatonin, vitamin D3, and their combination, with concomitant downregulation of Bcl-2 gene and protein expression. The Bax/BCL-2 ratio was increased significantly (p < 0.001) suggesting potential therapeutic treatments.
The results suggest that treatment with melatonin and vitamin D3 inhibits the proliferation and induced apoptosis in breast cancer cells. We report here for the first time that this combination has effectively activated Bax and downregulated BCL-2 at the DNA and protein level.