Targeting Autophagy to Overcome Chemoresistance and Immune Resistance in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) remains one of the most challenging subtypes of breast cancer to treat, defined by its molecular heterogeneity, absence of hormone receptors, and poor clinical outcomes. While this difficulty with cancer cells persists even in the presence of chemotherapy and immune checkpoint inhibitors (ICIs), one critical factor linked to both chemoresistance and immune escape is autophagy. Autophagy is a cellular process with lysosomal recycling function. In TNBC, autophagy paradoxically shifts from tumor-suppressive to a tumor-promoting role. Autophagy was initially known to maintain genomic stability and alleviate oxidative damage. In TNBC, cancer cells use autophagy to detoxify platinum-induced DNA. damage, clear damaged mitochondria via mitophagy, recycle critical macromolecules, and sustain dormancy in cancer stem-like cells (CSCs). At the same time, the process of autophagic flux facilitates immune evasion, including PD-L1 expression stabilization, MHC-I degradation, and the establishment of an immunosuppressive tumor microenvironment (TME). The review encapsulates the progressive concepts of molecular regulation of autophagy, which involve key factors such as ULK1, VPS34, and non-coding RNAs (ncRNAs). These factors play a significant role in chemoresistance, taxanes, anthracyclines, and platinum compounds. The review also discusses various strategies for translation that aim to circumvent or suppress autophagy-mediated chemoresistance, including autophagy inhibitors, natural compounds, and nanoparticle-based formulations, with a focus on their synergistic potential with ICIs and chemotherapeutic agents. Targeting autophagy has shown considerable potential for effectively addressing chemoresistance in TNBC. Future studies should focus on addressing chemoresistance and immunoresistance through autophagy-based therapies.