Boosting Nanomedicine Efficacy with Hyperbaric Oxygen Therapy

Nanomedicine has been a hot topic in the field of tumor therapy in the past few decades. Because of the enhanced permeability and retention effect (EPR effect), nanomedicine can passively yet selectively accumulate at tumor tissues. As a result, it can improve drug concentration in tumor tissues and reduce drug distribution in normal tissues, thereby contributing to enhanced antitumor effect and reduced adverse effects. However, the therapeutic efficacy of anticancer nanomedicine is not satisfactory in clinical settings. Therefore, how to improve the clinical therapeutic effect of nanomedicine has become an urgent problem. The grand challenges of nanomedicine lie in how to overcome various pathophysiological barriers and simultaneously kill cancer cells effectively in hypoxic tumor microenvironment (TME). To this end, the development of novel stimuli-responsive nanomedicine has become a new research hotspot. While a great deal of progress has been made in this direction and preclinical results report many different kinds of promising multifunctional smart nanomedicine, the design of these intelligent nanomedicines is often too complicated, the requirements for the preparation processes are strict, the cost is high, and the clinical translation is difficult. Thus, it is more practical to find solutions to promote the therapeutic efficacy of commercialized nanomedicines, for example, Doxil®, Oncaspar®, DaunoXome®, Abraxane®, to name a few. Increasing attention has been paid to the combination of modern advanced medical technology and nanomedicine for the treatment of various malignancies. Recently, we found that hyperbaric oxygen (HBO) therapy could enhance Doxil® antitumor efficacy. Inspired by this study, we further carried out researches on the combination of HBO therapy with other nanomedicines for various cancer therapies, and revealed that HBO therapy could significantly boost antitumor efficacy of nanomedicine-mediated photodynamic therapy and photothermal therapy in different kinds of tumors, including hepatocellular carcinoma, breast cancer, and gliomas. Our results implicate that HBO therapy might be a universal strategy to boost therapeutic efficacy of nanomedicine against hypoxic solid malignancies.