Harnessing carbon monoxide-releasing platforms for cancer therapy

Carbon monoxide (CO) is a gaseous molecule that has drawn growing concerns for cancer treatment, due to its multifaceted regulation of cellular function and the tumor microenvironment. The past decades have witnessed extensive efforts into this emerging field, centered in the development of intelligent CO donors and CO delivery based on nanomaterials. However, CO delivery is beset with biosafety problems arising from burst release and the demand for high therapeutic concentrations in tumor tissues. In this review, we provide an overview of physiological and therapeutic effects of CO, and discuss the recent progress in CO application for cancer treatment. The main emphasis is placed on CO-releasing platforms to overcome the challenges in delivery and underlying synergistic mechanism against cancer. Eventually, the obstacles confronted and future directions of CO therapy are also highlighted for future clinical translation.