Caged Monomethyl Auristatin F (MMAF) for Cell-Specific Activation Using a 488-nm-Optimized Photolabile Group

Area of Science:

• Chemical Biology
• Photochemistry
• Molecular Imaging

Background:

• Photolabile protecting groups (PPGs) are crucial for spatiotemporal control of bioactive molecules.
• Efficient uncaging under biologically compatible conditions is essential for PPG utility.

Purpose of the Study:

• To develop a coumarin-based PPG optimized for 488 nm excitation for precise uncaging.
• To apply this PPG to control the release of monomethyl auristatin F (MMAF).

Main Methods:

• Design and synthesis of a coumarin-based PPG for 488 nm light.
• Caging of MMAF's C-terminal carboxylate to create a cell-permeant prodrug.
• Photoactivation of the prodrug using standard fluorescence microscopy irradiance.

Main Results:

• The optimized PPG enables efficient uncaging at 488 nm, compatible with GFP imaging.
• The caged MMAF (cMMAF) prodrug becomes cell-permeant and releases active MMAF upon photoactivation.
• Pharmacological activity of MMAF was successfully confined to single cells, demonstrating a "neighboring effect".

Conclusions:

• A novel coumarin-based PPG optimized for 488 nm excitation offers precise spatiotemporal control of bioactive molecules.
• This PPG enables targeted drug delivery and release, with potential applications in cancer therapy and chemical biology research.