Abstract
It has been established that melatonin (Mlt) and retinoic acid, individually, inhibit the proliferation of the estrogen receptor-alpha (ER alpha)-positive MCF-7 breast cancer cell line.
Our laboratory has previously demonstrated that Mlt and all-trans-retinoic acid (atRA) not only inhibit the proliferation, but also induce apoptosis of MCF-7 cells when used in a sequential regimen of Mlt followed 24 h later by atRA.
Using this same MCF-7 breast cancer cell line, we investigated the potential pathways through which apoptosis is being induced. We found that treatment of MCF-7 cells with Mlt for 24 h before the addition of atRA decreased the protein levels of the death suppressor, Bcl-2, and increased, although with different time courses, the levels of the death promoters, Bax and Bak; however, there was no change in the levels of the tumor suppressor gene, p53. MCF-7 cells treated sequentially with Mlt and atRA also demonstrated an enhanced sensitivity to the apoptotic effects of atRA, which did not appear to be due to increased expression of the retinoic acid receptors, RAR alpha or RXR alpha, but rather to enhanced transcriptional activity of the RAR alpha.
These data suggest that the sequential treatment regimen of Mlt and atRA may induce apoptosis by modulation of members of the Bcl-2 family of proteins.
Thus, this combinatorial regimen, which reduces the concentration of atRA needed for clinical efficacy while enhancing its anti-tumorigenic activity, could be of great therapeutic benefit, and may, in fact, specifically induce the regression of established breast tumors due to its apoptosis-promoting effects.
See also:
- Official Web Site: The Di Bella Method;
- About Melatonin - In vitro, review and in vivo publications;
- Publication: Melatonin anticancer effects: Review (from Di Bella's Foundation);
- Publication: Key aspects of melatonin physiology: 30 years of research (from Di Bella's Foundation);
- Solution of retinoids in vitamin E in the Di Bella Method biological multitherapy;
- Somatostatin in oncology, the overlooked evidences - In vitro, review and in vivo publications;
- Publication, 2018 Jul: Over-Expression of GH/GHR in Breast Cancer and Oncosuppressor Role of Somatostatin as a Physiological Inhibitor (from Di Bella's Foundation);
- Publication, 2019 Aug: The Entrapment of Somatostatin in a Lipid Formulation: Retarded Release and Free Radical Reactivity (from Di Bella's Foundation);
- Publication, 2019 Sep: Effects of Somatostatin and Vitamin C on the Fatty Acid Profile of Breast Cancer Cell Membranes (from Di Bella's Foundation);
- The Di Bella Method (A Fixed Part - Dihydrotachysterol, Alfacalcidol, synthetic Vitamin D3);
- Vitamin D (analogues and/or derivatives) and cancer - In vitro, review and in vivo publications;
- Complete objective response to biological therapy of plurifocal breast carcinoma;
- Neuroblastoma: Complete objective response to biological treatment;
- Oesophageal squamocellular carcinoma: a complete and objective response.