Objective

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.

Methods

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.

Results

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.

Conclusion

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.

中文翻译：

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褪黑素和维生素D3对MCF-7乳腺癌细胞Bcl-2和BAX基因表达的影响

目的

流行病学和实验研究的令人信服的证据表明，昼夜节律的破坏和褪黑激素合成的降低是乳腺癌的危险因素。随着全球乳腺癌病例的不断增加，迫切需要更安全，有效和替代治疗且副作用较小的治疗策略。这项研究旨在研究褪黑素和维生素D3对MCF-7癌细胞系中两个凋亡因子BCL-2和Bax基因表达的影响。

方法

通过MTT还原测定法研究了对褪黑激素（1 nM，5 nM和10 nM）和维生素D3（0.5 nM，1 nM和10 NM）的反应的细胞活力（MCF-7）。选择褪黑激素（5 nM）和维生素D3（0.5 nM）的最佳剂量进行组合和测定Bax / BCL-2的比例。通过mRNA表达确定基因BCL-2和Bax表达的变化，而蛋白质印迹法用于检测蛋白质水平上BCL-2和Bax表达的变化。

结果

褪黑激素，维生素D3及其组合的治疗使Bax基因表达和蛋白质表达上调，同时Bcl-2基因和蛋白质表达也随之下调。Bax / BCL-2比率显着增加（p <0.001），表明可能的治疗方法。

结论

结果表明，褪黑激素和维生素D3处理可抑制乳腺癌细胞的增殖并诱导其凋亡。我们在这里首次报道这种组合在DNA和蛋白质水平上有效激活了Bax并下调了BCL-2。