BODIPY-Based Mitochondrial Targeted NIR-Responsive CO-Releasing Platform for the On-Demand Release of CO to Treat Cancer.

It is an established fact that cancer is one of the most serious public health issues after coronary artery disease. Thus, exploring more effective and efficient therapeutic protocols over the traditional chemotherapeutic strategy is imperative to improving cancer survivorship and patient quality of life. In this respect, recent reports on molecularly engineered meso -substituted BODIPY have shown remarkable effects as a photoresponsive CO-releasing platform for the on-demand release of CO to treat cancer. Herein, we designed and synthesized two meso -substituted BODIPY photoresponsive CO-releasing molecules (photoCORMs). These BODIPY derivatives were tethered to a phenoxymethylpyridine moiety and oligoethylene glycol to maintain a hydrophilic-hydrophobic balance and improved cell permeability. The cell imaging experiments demonstrated that oligoethylene glycol containing photoCORM-1 efficiently internalized and preferentially localized at the mitochondria. To understand the mechanistic aspect of preferential localization into the mitochondria, live cell imaging was also carried out. Photorelease of CO was directly monitored by the inline IR spectroscopic technique. Finally, in vitro cytotoxicity and apoptosis assays on MDA-MB-231 cell lines clearly showed that photoCORM-1 induced apoptosis-mediated cell killing on account of photoreleased CO, which otherwise showed insignificant toxicity even at a very high concentration of ∼50 μM.