Decoding novel mechanisms and emerging therapeutic strategies in breast cancer resistance

Breast cancer, an intricate and highly heterogeneous disorder, has presently afflicted 2.09 million females globally. Nonetheless, chemoresistance remains a paramount challenge in the treatment of breast cancer. Owing to its assorted nature, the chemoresistant mechanisms of breast cancer still need intensive research. The presently available interventions are inadequate to target chemoresistance, therefore more efficient alternatives are urgently needed to improvise existing therapeutic regimens. A myriad of strategies is being explored, such as cancer stem cells (CSCs), immunotherapy, gene therapy, miRNA drug carriers and combination treatment to surmount chemoresistance. Accumulating evidence suggests that abnormalities related to the biogenesis of miRNAs are associated with breast cancer progression and chemoresistance. Additionally, miRNA has been found to mediate several cellular processes and the key markers of breast cancer. miRNAs thus are a promising option for the diagnosis and treatment of breast cancer. CSCs possess responses to cancer treatment, including epithelial-to-mesenchymal transition (EMT), stimulation of signaling pathways mediating auto-renewal, expression of drug transporters or proteins detoxification. The screening of anticancer therapeutics that target CSCs could be another potential alternate for chemoresistant breast cancer. Nanoparticles as chemotherapeutics carriers including liposome, nanoemulsion, dendrimers, gold nanoparticles, etc put forward the options to have numerous drug or imaging agents for theranostics and combinational therapy. This review summarizes the chemoresistance mechanisms of miRNAs, CSCs as well as most recently documented therapeutic approaches for the treatment of chemoresistance in breast cancer.