Exosomal circular RNAs: A key player in cancer drug resistance

Chemotherapy is a main approach used to treat cancerous tumors. Nevertheless, the resistance to drugs that patients develop over time reduces the effectiveness of treatment and results in failure for many patients. Exosomes are tiny vesicles created by cells that are between 30 and 150 nm in size. They transport molecules like proteins, lipids, DNAs, RNAs, and to facilitate interaction between cells in the progression of tumors. Circular RNAs (circRNAs), which are covalently closed-loop RNA structures, govern numerous genes and signaling pathways to regulate the proliferation, death, and metastasis of cancer cells. Exosomes contain a large amount of circRNAs that are consistently expressed. Current research indicates that circRNAs have significant functions in chemotherapy resistance in different types of cancers. This review provides an overview of the role of exosomes in cancer chemotherapy resistance and examines how exosomal circRNAs regulate drug resistance in various cancers. •Chemotherapy faces challenges due to patient drug resistance over time.•Exosomes transport molecules and play a role in tumor progression.•Circular RNAs (circRNAs) regulate cancer cell behavior and metastasis.•Exosomal circRNAs are implicated in chemotherapy resistance across cancer types.•Understanding exosomal circRNAs may lead to improved anti-tumor drugs.