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Optimized Near-IR Fluorescent Agents for in Vivo Imaging of Btk Expression
Eunha Kim1, Katherine S Yang1, Rainer H Kohler1
1†Center for Systems Biology, Massachusetts General Hospital, 185 Cambridge Street, CPZN 5206, Boston, Massachusetts 02114, United States.
Abstract:
Bruton's tyrosine kinase (Btk) is intricately involved in anti-apoptotic signaling pathways in cancer and in regulating innate immune response. A number of Btk inhibitors are in development for use in treating B-cell malignancies and certain immunologic diseases. To develop robust companion imaging diagnostics for in vivo use, we set out to explore the effects of red wavelength fluorochrome modifications of two highly potent irreversible Btk inhibitors, Ibrutinib and AVL-292. Surprisingly, we found that subtle chemical differences in the fluorochrome had considerable effects on target localization. Based on iterative designs, we developed a single optimized version with superb in vivo imaging characteristics enabling single cell Btk imaging in vivo. This agent (Ibrutinib-SiR-COOH) is expected to be a valuable chemical tool in deciphering Btk biology in cancer and host cells in vivo.
Insights
Researchers developed a novel imaging agent for Bruton's tyrosine kinase (Btk). This tool allows for single-cell Btk imaging in vivo, aiding cancer and immunology research.
Area of Science:
- Biochemistry
- Molecular Biology
- Pharmacology
Background:
- Bruton's tyrosine kinase (Btk) plays a crucial role in anti-apoptotic signaling in cancer and innate immune responses.
- Btk inhibitors are under development for B-cell malignancies and immunologic diseases.
- There is a need for in vivo imaging diagnostics to study Btk activity.
Purpose of the Study:
- To explore the impact of red wavelength fluorochrome modifications on Btk inhibitors.
- To develop a robust companion imaging diagnostic for in vivo Btk visualization.
- To create a tool for deciphering Btk biology in cancer and host cells.
Main Methods:
- Modification of two irreversible Btk inhibitors, Ibrutinib and AVL-292, with red wavelength fluorochromes.
- Iterative design and testing of fluorochrome-labeled inhibitors for in vivo imaging.
- Evaluation of target localization and imaging characteristics.
Main Results:
- Subtle chemical differences in fluorochromes significantly affected target localization.
- An optimized Btk inhibitor derivative, Ibrutinib-SiR-COOH, demonstrated excellent in vivo imaging properties.
- Single-cell Btk imaging in vivo was achieved with the developed agent.
Conclusions:
- Fluorochrome modifications are critical for developing effective in vivo imaging agents.
- Ibrutinib-SiR-COOH is a valuable tool for in vivo Btk research.
- This agent will advance the understanding of Btk biology in cancer and immune cells.
