Inhibition of Autophagy on Melatonin‑Induced Apoptosis in MCF-7 and MDA-MB-231 Cell Lines

Abstract

Aim: We looked at the connection between autophagy and apoptosis after our prior research indicated that melatonin could cause MCF-7 and MDA-MB-231 cells in the present study.
 Material and Method: In order to investigate the autophagy inhibition’s effect on the melatonin-induced BC cells’ apoptosis, melatonin and/or 3-methyladenine (3-MA, autophagy inhibitor) have been utilized. Melatonin was applied to the cells following a 5-mM 3-MA pre-cultivation. Then, apoptosis was detected by the TUNEL method. The technique for double immunofluorescence labeling was used to identify the molecular alterations in Bax/Bcl-2 expression. To evaluate the cell viability, the MTT test was used.
 Results: When an autophagy inhibitor, 3-MA, and melatonin treatment were co-administered in MCF-7 cells, apoptosis was decreased, compared to melatonin treatment alone, but it was not significant. In addition, 3-MA application downregulated Bax expression compared with melatonin alone treatment. Combined therapy markedly elevated apoptosis and significantly up-regulated Bax protein in MDA-MB-231 cells. 
 Conclusion: Taken together, in MCF-7 cells, autophagy’s inhibition contributes to the downregulation of apoptosis, whereas increased apoptosis is seen in MDA-MB-231 cells. Inhibiting autophagy in these cells treated with melatonin could serve as a self-defense mechanism, and This might be a good strategy for breast cancer adjuvant treatment.