| Abstract: | Breast cancer (BC) is the most common heterogeneous disease in women and one of the leading causes of
cancer-related death. Surgery, chemotherapy, radiotherapy, hormone, and targeted therapy are the gold standards for
BC treatment. One of the significant challenges during the treatment of BC represents resistance to
chemotherapeutics, resistance that severely limits the use and effectiveness of the drugs used for BC treatment.
Therefore, it is essential to develop new strategies to improve therapeutic efficacy. Circular RNAs (circRNAs) are a
large group of non-coding RNAs that covalently form closed circular loops by joining their 5′, and 3′; ends.
Accumulating evidence suggests that circRNAs have a vital role in cancer development, progression, and BC
resistance to chemotherapy. The purpose of this review is to discuss the biological properties of circRNAs, and how
circRNAs induce resistance to conventional therapeutic anti-cancer drugs used in BC treatment, by emphasizing and
summarizing the potential roles of circRNAs in mechanisms of drug resistance, such as drug efflux, apoptosis
dysfunction, autophagy, and DNA damage repair. CircRNAs are associated with drug resistance via ATP-binding
cassette (ABC) efflux transporters, while some others by inhibition of cell apoptosis, thus leading to resistance to
tamoxifen in BC cells. In contrast, others are involved in the promotion of BC cells chemoresistance by doxorubicininduced autophagy. CircRNAs may have clinical significance in regulating or overcoming BC drug resistance and may
give directions towards a novel approach to personalized BC treatment. CircRNAs may significantly contribute to the
identification of new therapeutic targets for the prevention of BC chemoresistance. |
