Near-IR Photorelease Chemistry: Discovery and Applications

Division Of Basic Sciences - Nci

Investigators

Linked publications & trials

Abstract

We have developed an uncaging reaction sequence initiated by near-IR light using readily synthesized C4'-dialkylamine-substituted heptamethine cyanines. We have shown that a variety of phenol- and amine- containing small molecules are quickly uncaged upon irradiation with low energy light. Detailed mechanistic studies involving mass spectrometry, NMR, and absorbance techniques have shown that release occurs through regioselective C-C cleavage and then hydrolysis of the C4'-amine. We are currently broadening the scope of the release process and examining aspects of the mechanism in detail using computational (collaboration with Dr. Joseph Ivanic) and experimental techniques. In this effort, we have developed an approach that enables the control release of amine payload through an approach that involves cyanine photooxidation followed by beta-elimination. Existing methods that use light for therapeutic interventions typically rely on the local generation of reactive oxygen species (ROS). The local delivery of potent therapeutic agents elicit alternative mechanistic paradigms, while achieving otherwise unattainable potency. We are applying our light-cleavable chemistry for targeted drug delivery. This approach merges the unique potency of small molecule drugs with the high spatial control afforded by light release and molecular targeting. The use of tissue penetrant, cytocompatible near-IR light is critical because existing uncaging chemistries using UV or blue light would not be suitable for this application. In this area, we reported the first example of near-IR light cleavable antibody drug conjugate strategy. We have developed conjugates that release the potent anticancer natural product, duocarmycin. These conjugates can be tracked in vivo using fluorescence and uncaged attainable flux from an external CW laser source. These compounds have shown excellent antitumor activity in various in vivo models. We are currently pursuing additional strategies to enable to the delivery of these molecules to various solid tumors.