ABT-737 — The Foundational BCL-2 Senolytic
ABT-737 is a foundational senolytic compound that selectively induces apoptosis in senescent cells by inhibiting the BCL-2 family of anti-apoptotic proteins. While it was never developed for human use due to poor bioavailability, it served as the critical proof-of-concept molecule that paved the way for modern senolytic therapies like Navitoclax.
Mechanism of Action
ABT-737 is a BH3 mimetic small molecule that acts as a potent, selective inhibitor of the anti-apoptotic BCL-2 family proteins, specifically BCL-2, BCL-XL, and BCL-W. Senescent cells upregulate these anti-apoptotic proteins (forming the SCAP, or senescent cell anti-apoptotic pathway) to resist apoptosis despite accumulating damage. By binding to the hydrophobic groove of these BCL-2 family members, ABT-737 prevents them from sequestering pro-apoptotic proteins like BAX and BAK. This disruption triggers mitochondrial outer membrane permeabilization (MOMP) and subsequent caspase-dependent apoptosis, selectively eliminating senescent cells while sparing healthy tissue.
Human Trial Evidence
No published human longevity trials. Animal/in-vitro evidence only. ABT-737 was never advanced to human clinical trials due to poor oral bioavailability, leading to the development of its orally bioavailable derivative, Navitoclax (ABT-263).
Dosing Protocol
Unestablished in humans. ABT-737 is an experimental preclinical compound not approved for human use. It is typically administered via intraperitoneal injection in murine models.
Safety & Contraindications
ABT-737 is not approved for human use. In preclinical models, the primary dose-limiting toxicity of BCL-2/BCL-XL inhibitors is severe, rapid-onset thrombocytopenia (depletion of blood platelets), as platelet survival is highly dependent on BCL-XL. It is strictly contraindicated for human consumption outside of controlled research settings.