The broad goal of this proposal is to use fast in vivo click chemistries to enable biomedical imaging with affinity ligands such as monoclonal antibodies. The candidate, Neal Devaraj, has received extensive training in the field of chemistry and now wishes to transition to biomedical research. His immediate goal is to further develop skill sets through immersion in translational research and to make significant contributions to the field of in vivo imaging. Long term, the candidate wishes to make a full transition from chemist to independent biomedical research scientist. The candidate proposes to carry out the proposal at the Harvard/MGH Center for Systems Biology under the mentorship of Dr. Ralph Weissleder MD PhD. In addition to the research proposal, his career development plan includes supplemental coursework, mentored readings, journal clubs, attendance and presentation at several seminars and conferences, practical exposure to the imaging sciences, and close formal interaction with both his mentor and an advisory committee consisting of Prof. Robert Langer, Prof. Moungi Bawendi, and Prof. Marcelo Di Carli. The research plan aims to develop platform chemistries to allow site specific in vivo targeting of affinity ligands once they have homed to their target (i.e. decoupled administration of affinity ligand and imaging reporter). Though a large number of targeting ligands have been developed to date, target-reporter constructs have inherent pharmacokinetics which are undesirable for in vivo imaging. To achieve site specific coupling, the candidate proposes to work with the recently introduced tetrazine/strained dienophile cycloaddition. This extremely rapid reaction is highly selective, irreversible, and can be performed in physiological conditions. The proposal aims to build on this cutting-edge technology and to develop generic in vivo click reactions for molecular imaging with positron emission tomography (PET).
The specific aims are to 1) develop and characterize a panel of fast """"""""click"""""""" reactions for radioisotope labeling and 2) pursue in vivo click labeling for biomedical imaging. To test this method, the candidate will create dienophile affinity ligands against A33 glycoprotein, a surface persistent marker that is highly expressed in human colon cancers. Mice bearing primary and metastatic colon cancer will be injected with dienophile affinity ligands. After several days of clearance, a small, readily cleared tetrazine imaging probe will be administered. Imaging with PET will be used to quantify probe localization and the method will be optimized and compared to other methods such as direct labeling of affinity ligands and the metabolic reporter 18fluorodeoxglucose. If successful, the development of in vivo """"""""click"""""""" chemistry for biomedical imaging will provide a nearly universal methodology for in vivo imaging of virtually any targeting affinity ligand.

Public Health Relevance

(provided by applicant): This project aims to develop improved methods for biomedical imaging. If successful this would lead to detection of disease much earlier when they are curable, improved diagnosis of diseased condition so appropriate treatment can be administered, and better tools for determining the effectiveness of new therapies.

National Institute of Health (NIH)
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Research Scientist Development Award - Research & Training (K01)
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Special Emphasis Panel (ZEB1-OSR-B (O2))
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Erim, Zeynep
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Massachusetts General Hospital
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Wu, Haoxing; Devaraj, Neal K (2018) Advances in Tetrazine Bioorthogonal Chemistry Driven by the Synthesis of Novel Tetrazines and Dienophiles. Acc Chem Res 51:1249-1259
Nichols, Brandon; Qin, Zhengtao; Yang, Jun et al. (2014) 68Ga chelating bioorthogonal tetrazine polymers for the multistep labeling of cancer biomarkers. Chem Commun (Camb) 50:5215-5217
Yang, Jun; Liang, Yong; Še?kut?, Jolita et al. (2014) Synthesis and reactivity comparisons of 1-methyl-3-substituted cyclopropene mini-tags for tetrazine bioorthogonal reactions. Chemistry 20:3365-75
Wu, Haoxing; Cisneros, Brandon T; Cole, Christian M et al. (2014) Bioorthogonal tetrazine-mediated transfer reactions facilitate reaction turnover in nucleic acid-templated detection of microRNA. J Am Chem Soc 136:17942-5
Wu, Haoxing; Yang, Jun; Še?kut?, Jolita et al. (2014) In situ synthesis of alkenyl tetrazines for highly fluorogenic bioorthogonal live-cell imaging probes. Angew Chem Int Ed Engl 53:5805-9
Seckute, Jolita; Devaraj, Neal K (2013) Expanding room for tetrazine ligations in the in vivo chemistry toolbox. Curr Opin Chem Biol 17:761-7
Seckute, Jolita; Yang, Jun; Devaraj, Neal K (2013) Rapid oligonucleotide-templated fluorogenic tetrazine ligations. Nucleic Acids Res 41:e148
Cole, Christian M; Yang, Jun; Še?kut?, Jolita et al. (2013) Fluorescent live-cell imaging of metabolically incorporated unnatural cyclopropene-mannosamine derivatives. Chembiochem 14:205-208
Devaraj, Neal K; Thurber, Greg M; Keliher, Edmund J et al. (2012) Reactive polymer enables efficient in vivo bioorthogonal chemistry. Proc Natl Acad Sci U S A 109:4762-7
Yang, Jun; Še?kut?, Jolita; Cole, Christian M et al. (2012) Live-cell imaging of cyclopropene tags with fluorogenic tetrazine cycloadditions. Angew Chem Int Ed Engl 51:7476-9

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