Аннотация
Autophagy is a fundamental cellular process responsible for recycling cytoplasmic components, playing acrucial for maintaining cellular homeostasis and influencing cancer progression. Breast cancer comprises various molecular subtypes with different levels of aggressiveness and therapeutic responses. This study aimed to investigate differences in autophagic activity and flux between two breast cancer cell lines-MDA-MB-231, a triple-negative aggressive subtype, and MCF-7, a luminal hormone-sensitive subtype-compared to non-tumorigenic MCF-10A breast epithelial cells. We also evaluated the effects of pharmacological modulation on autophagy to understand how autophagic status may influence cancer cell behavior. Methods.We conducted an in vitro study with MDA-MB-231, MCF-7, and MCF-10A cells. Autophagic activity was measured by analyzing LC3B and p62 protein levels through western blotting and immunofluorescence microscopy. Pharmacological modulation included nutrient deprivation to induce autophagy, 3-methyladenine to inhibit initiation, and Bafilomycin A1 to block degradation. Data were analyzed descriptively and comparatively to highlight differences in marker expression.Results.Both cancer cell lines showed higher basal autophagy than MCF-10A. MCF-7 cellsaccumulated p62 and LC3B-II, suggesting impaired degradation. MDA-MB-231 cells showed reduced p62 and increased LC3B-II, indicating active flux. Upon pharmacological treatment, MDA-MB-231 cells responded with expected marker changes, confirming functionalautophagy. In contrast, MCF-7 cells showed further accumulation of LC3B-II and p62, reinforcing impaired degradation. Conclusion.This studyhighlights distinctdifferences in autophagy between breast cancer subtypes. MDA-MB-231 cells maintain active autophagy, potentially supporting their aggressive behavior and adaptability. MCF-7 cells exhibit a block in degradation, which may limit their response to metabolic stress and therapy. These insights underscore the importance of considering autophagy status in breast cancer treatment strategies.Keywords: autophagy, autophagic flux, breast cancer, triple-negative breast cancer.