Developing Novel Photostable Fluorescent Probes for Detecting Granzyme and Evaluating Natural Killer Cell Activity

Project: Research

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Cancer immunotherapy holds great promise in cancer treatment. However, immunotherapy today is still confronted with the problem of low patient response due to various challenges, including immunosuppression, tumor heterogeneity and drug resistance. Developing imaging tools that can monitor immune responses will not only help to evaluate the results of immunotherapy, but also facilitate the discovery of new immunotherapeutic methodologies. Cytotoxic T lymphocytes (CTLs) and NK cells are instrumental for immune recognition and defense by killing virus-infected cells and tumor cells. They both utilize cytotoxic granzymes to exert cell killing functions. Chemical tools capable of selectively detectinggranzymes will help to advance our understanding of the roles of granzymes in immunology. Such tools will also facilitate the development of drugs for activating or inhibiting granzyme. In addition, fluorescent probes for detecting granzymes will providea useful approach for monitoring tumor response to immunotherapy. In this project, we will first develop a new class of photostable fluorophores for designing granyzme probes. The incorporation of a donor 9,10-dimethyl-9,10-dihydroacridine (MA) moiety to the rhodamine skeleton can lead to lengthened absorption and emissionwavelength, enlarged Stokes shift, and superior photostability. We plan to introduce MA donors to different fluorophores to engineer novel photostable dyes with red to NIR emission. After obtaining fluorophores with excellent photophysical properties, we willdesign two types of fluorescent probes for investigating the functions of granzyme B in the NK cell-mediated killing process of cancer cells. The FRET-based probe will allow us to monitor the dynamic enzymatic activity of granzyme B in NK cell killing assay. Onthe other hand, the inhibitor-based probe installed with diphenyl phosphonate moiety will form a covalent bond with granzyme B, enabling us to track the precise localization of granzyme B in the entire killing process. In the final stage of the proposed study, we aim to develop a granzyme-responsive theranostic prodrug platform to selectively image and kill cancer cells. By rationally designing prodrugs that can be activated by granzyme, the drug’s selectivity towards cancer cells will be increased. With the combination of immunotherapy and chemotherapy treatment, its anti-cancer activity will also be enhanced. Through the proposed study, we aim to develop dynamic and robust chemical tools for detecting granzyme B, evaluating the killing activity of NK cells and enhancing the cancer treatment efficacy. 


Project number9043387
Grant typeGRF
StatusNot started
Effective start/end date1/01/23 → …