An inducible system for in vitro and in vivo Fas activation using FKBP-FRB-rapamycin complex

Area of Science:

• Molecular Biology
• Cell Biology
• Immunology

Background:

• Inducible activation systems are crucial for studying molecular functions in space and time.
• A chemically inducible system for Fas (CD95/APO-1) capable of inducing apoptosis and non-apoptotic pathways has been lacking.

Purpose of the Study:

• To engineer a novel, chemically inducible Fas activation system using rapamycin-induced dimerization.
• To investigate the system's efficacy in controlling apoptosis and non-apoptotic pathways in various cell types.
• To evaluate the system's potential for in vivo therapeutic applications, specifically tumor cell apoptosis.

Main Methods:

• Engineered a rapamycin-induced dimerization system for Fas utilizing FKBP and FRB proteins.
• Administered rapamycin to induce Fas activation and observed cellular responses, including apoptosis and non-apoptotic pathway activation.
• Tested the system in vitro in various cell lines and in vivo via intracranial delivery in a model system.

Main Results:

• Rapamycin treatment specifically induced cellular apoptosis via the engineered Fas system.
• In neurons and cells with high c-FLIP expression, Fas activation led to non-apoptotic pathway activation instead of cell death.
• Intracranial delivery demonstrated the system's ability to induce tumor cell apoptosis upon rapamycin administration.

Conclusions:

• Developed a novel, highly efficient, and temporally precise inducible Fas activation system.
• The system effectively controls both apoptotic and non-apoptotic Fas signaling pathways.
• This inducible system holds promise as a potential therapeutic strategy for targeting tumor cells.