BH3-only proteins Noxa, Bmf, and Bim are necessary for arsenic trioxide-induced cell death in myeloma.
The use of arsenic trioxide (ATO) to treat multiple myeloma (MM) is supported by preclinical studies as well as several phase 2 studies, but the precise mechanism(s) of action of ATO has not been completely elucidated. We used gene expression profiling to determine the regulation of apoptosis-related genes by ATO in 4 MM cell lines and then focused on Bcl-2 family genes. ATO induced up-regulation of 3 proapoptotic BH3-only proteins (Noxa, Bmf, and Puma) and down-regulation of 2 antiapoptotic proteins Mcl-1 and Bcl-X(L). Coimmunoprecipitation demonstrated that Noxa and Puma bind Mcl-1 to release Bak and Bim within 6 hours of ATO addition. Bak and Bim are also released from Bcl-X(L). Silencing of Bmf, Noxa, and Bim significantly protected cells from ATO-induced apoptosis, while Puma silencing had no effect. Consistent with a role for Noxa inhibition of Mcl-1, the Bad-mimetic ABT-737 synergized with ATO in the killing of 2 MM lines. Finally, Noxa expression was enhanced by GSH depletion and inhibited by increasing GSH levels in the cells. Understanding the pattern of BH3-only protein response should aid in the rational design of arsenic-containing regimens.
Morales
Alejo A
AA
Microbiology and Immunology and The Sylvester Comprehensive Cancer Center, University of Miami, Miller School of Medicine, FL, USA.
Gutman
Delia
D
Lee
Kelvin P
KP
Boise
Lawrence H
LH
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000502:physiology; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics* / Q000502:physiology; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D000072224:Bcl-2-Like Protein 11; D016923:Cell Death; D045744:Cell Line, Tumor; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000473:pathology; D010087:Oxides / Q000494:pharmacology*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000502:physiology
D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; D001152:Arsenicals; C000606775:BCL2L11 protein, human; C486655:BMF protein, human; D000072224:Bcl-2-Like Protein 11; D008565:Membrane Proteins; D010087:Oxides; C498702:PMAIP1 protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D000077237:Arsenic Trioxide