Oral Carbon Monoxide Enhances Autophagy Modulation in Prostate, Pancreatic, and Lung Cancers
Jianling Bi, Emily Witt, Megan K. McGovern, Arielle B. Cafi, Lauren L. Rosenstock, Anna B. Pearson, Timothy J. Brown, Thomas B. Karasic, Lucas C. Absler, Srija Machkanti, Hannah Boyce, David Gallo, Sarah Becker, Keiko Ishida, Joshua Jenkins, Alison Hayward, Alexandra Scheiflinger, Kellie L. Bodeker, Ritesh Kumar, Scott K. Shaw, Salma K. Jabbour, Vitor A. Lira, Michael D. Henry, Michael S. Tift, Leo E. Otterbein, Giovanni Traverso, James D. Byrne
Abstract
Modulation of autophagy, specifically its inhibition, stands to transform the capacity to effectively treat a broad range of cancers. However, the clinical efficacy of autophagy inhibitors has been inconsistent. To delineate clinical and epidemiological features associated with autophagy inhibition and a positive oncological clinical response, a retrospective analysis of patients is conducted treated with hydroxychloroquine, a known autophagy inhibitor. A direct correlation between smoking status and inhibition of autophagy with hydroxychloroquine is identified. Recognizing that smoking is associated with elevated circulating levels of carbon monoxide (CO), it is hypothesized that supplemental CO can amplify autophagy inhibition. A novel, gas-entrapping material containing CO in a pre-clinical model is applied and demonstrated that CO can dramatically increase the cytotoxicity of autophagy inhibitors and significantly inhibit the growth of tumors when used in combination. These data support the notion that safe, therapeutic levels of CO can markedly enhance the efficacy of autophagy inhibitors, opening a promising new frontier in the quest to improve cancer therapies.