Two-photon uncaging of bioactive thiols in live cells at wavelengths above 800 nm

Development of visible-light-activatable photocaged PROTACs

Photocaged proteolysis-targeting chimeras (PROTACs), which employ light as a stimulus to control protein degradation, have recently garnered considerable attention as both powerful chemical tools and a promising therapeutic strategy. However, the poor penetration depth of traditionally used ultraviolet light and the deficiency of alternative caging positions have restricted their applications in biological systems. By installing a diverse array of photocaged groups, with excitation wavelengths ranging from 365 nm to 405 nm, onto different positions of cereblon (CRBN) and Von Hippel-Lindau (VHL)-recruiting Brd4 degraders, we conducted the first comprehensive study on visible-light-activatable photocaged PROTACs to the best of our knowledge. We found the A2, A4 and B3 positions to be most effective at regulating the activity of the degraders, and to provide the resulting molecules (9-12 and 17) as potent visible-light-controlled degraders in live cells.

Discovery of a Novel Photocaged PI3K Inhibitor Capable of Real-Time Reporting of Drug Release

A novel photocaged PI3K inhibitor 2 was designed and synthesized by introducing a cascade photocaging group to block its key interaction with the kinase. Upon UV light irradiation, the photocaged compound released a highly potent PI3K inhibitor to recover its anticancer properties and a fluorescent dye for real-time reporting of drug release, providing a new approach for studying the PI3K signaling transduction pathway as well as developing precisely controlled cancer therapeutics.

Molecular platforms based on biocompatible photoreactions for photomodulation of biological targets

Photoirradiation provides a convenient and biocompatible approach for spatiotemporal modulation of biological systems with photoresponsive components. The construction of molecular platforms with a photoresponse to be integrated into biomolecules for photomodulation has been of great research interest in optochemical biology. In this review, we summarize typical molecular platforms that are integratable with biomolecules for photomodulation purposes. We categorize these molecular platforms according to their excitation light source, namely ultraviolet (UV), visible (Vis) or near-infrared (NIR) light. The protype chemistry of these molecular platforms is introduced along with an overview of their most recent applications for spatiotemporal regulation of biomolecular function in living cells or mice models. Challenges and the outlook are also presented. We hope this review paper will contribute to further progress in the development of molecular platforms and their biomedical use.

Visible-Light-Mediated Modification and Manipulation of Biomacromolecules

Chemically modified biomacromolecules-i.e., proteins, nucleic acids, glycans, and lipids-have become crucial tools in chemical biology. They are extensively used not only to elucidate cellular processes but also in industrial applications, particularly in the context of biopharmaceuticals. In order to enable maximum scope for optimization, it is pivotal to have a diverse array of biomacromolecule modification methods at one's disposal. Chemistry has driven many significant advances in this area, and especially recently, numerous novel visible-light-induced photochemical approaches have emerged. In these reactions, light serves as an external source of energy, enabling access to highly reactive intermediates under exceedingly mild conditions and with exquisite spatiotemporal control. While UV-induced transformations on biomacromolecules date back decades, visible light has the unmistakable advantage of being considerably more biocompatible, and a spectrum of visible-light-driven methods is now available, chiefly for proteins and nucleic acids. This review will discuss modifications of native functional groups (FGs), including functionalization, labeling, and cross-linking techniques as well as the utility of oxidative degradation mediated by photochemically generated reactive oxygen species. Furthermore, transformations at non-native, bioorthogonal FGs on biomacromolecules will be addressed, including photoclick chemistry and DNA-encoded library synthesis as well as methods that allow manipulation of the activity of a biomacromolecule.

Triggering biological processes: methods and applications of photocaged peptides and proteins

There has been a significant push in recent years to deploy fundamental knowledge and methods of photochemistry toward biological ends. Photoreactive groups have enabled chemists to activate biological function using the concept of photocaging. By granting spatiotemporal control over protein activation, these photocaging methods are fundamental in understanding biological processes. Peptides and proteins are an important group of photocaging targets that present conceptual and technical challenges, requiring precise chemoselectivity in complex polyfunctional environments. This review focuses on recent advances in photocaging techniques and methodologies, as well as their use in living systems. Photocaging methods include genetic and chemical approaches that require a deep understanding of structure-function relationships based on subtle changes in primary structure. Successful implementation of these ideas can shed light on important spatiotemporal aspects of living systems.