Activation of the Proapoptotic Bcl-2 Protein Bax by a Small Molecule Induces Tumor Cell Apoptosis

• Published in: Molecular and cellular biology Vol. 34; no. 7; pp. 1198 - 1207
• Main Authors: Zhao, Guoping, Zhu, Yanglong, Eno, Colins O., Liu, Yanlong, DeLeeuw, Lynn, Burlison, Joseph A., Chaires, Jonathan B., Trent, John O., Li, Chi
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 01-04-2014; American Society for Microbiology
• Subjects: Animals; Antineoplastic Agents - chemistry; Antineoplastic Agents - pharmacology; Apoptosis - drug effects; Apoptosis - physiology; bcl-2 Homologous Antagonist-Killer Protein - metabolism; bcl-2-Associated X Protein - chemistry; bcl-2-Associated X Protein - metabolism; Binding Sites; Cell Line; Cell Line, Tumor; Drug Screening Assays, Antitumor; Female; Humans; Hydrophobic and Hydrophilic Interactions; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Molecular; Neoplasms, Experimental - drug therapy; Neoplasms, Experimental - metabolism; Neoplasms, Experimental - pathology; Pyrazoles - chemistry; Pyrazoles - pharmacology; Pyridinium Compounds - chemistry; Pyridinium Compounds - pharmacology
• ISSN: 1098-5549; 0270-7306; 1098-5549
• DOI: 10.1128/MCB.00996-13

The proapoptotic Bcl-2 protein Bax by itself is sufficient to initiate apoptosis in almost all apoptotic paradigms. Thus, compounds that can facilitate disruptive Bax insertion into mitochondrial membranes have potential as cancer therapeutics. In our study, we have identified small-molecule compounds predicted to associate with the Bax hydrophobic groove by a virtual-screen approach. Among these, one lead compound (compound 106) promotes Bax-dependent but not Bak-dependent apoptosis. Importantly, this compound alters Bax protein stability in vitro and promotes the insertion of Bax into mitochondria, leading to Bax-dependent permeabilization of the mitochondrial outer membrane. Furthermore, as a single agent, compound 106 inhibits the growth of transplanted tumors, probably by inducing apoptosis in tumors. Our study has revealed a compound that activates Bax and induces Bax-dependent apoptosis, which may lead to the development of new therapeutic agents for cancer.