Therapeutic implication of carbon monoxide in drug resistant cancers.

Drug resistance is the major obstacle that undermines effective cancer treatment. Recently, the application of gas signaling molecules, e.g., carbon monoxide (CO), in overcoming drug resistance has gained significant attention. Growing evidence showed that CO could inhibit mitochondria respiratory effect and glycolysis, two major ATP production pathways in cancer cells, and suppress angiogenesis and inhibit the activity of cystathionine β-synthase that is important in regulating cancer cells homeostasis, leading to synergistic effects when combined with cisplatin, doxorubicin, or phototherapy, etc. in certain resistant cancer cells. In the current review, we attempted to have a summary of these research conducted in the past decade using CO in treating drug resistant cancers, and have a detailed interpretation of the underlying mechanisms. The critical challenges will be discussed and potential solutions will also be provided. The information collected in this work will hopefully evoke more effects in using CO for the treatment of drug resistant cancers.