The BCL2A1 gene as a pre-T cell receptorinduced regulator of thymocyte survival
JOURNAL OF EXPERIMENTAL MEDICINE
Authors: Mandal, M; Borowski, C; Palomero, T; Ferrando, AA; Oberdoerffer, P; Meng, FY; Ruiz-Vela, A; Ciofani, M; Zuniga-Pflucker, JC; Screpand, I; Look, AT; Korsmeyer, SJ; Rajewsky, K; von Boehmer, H; Aifantis, I
Abstract
The pre-T cell receptor (TCR) is expressed early during T cell development and imposes a tight selection for differentiating T cell progenitors. Pre-TCR-expressing cells are selected to survive and differentiate further, whereas pre-TCR- cells are "negatively" selected to die. The mechanisms of pre-TCR-mediated survival are poorly understood. Here, we describe the induction of the antiapoptotic gene BCL2A1 (A1) as a potential mechanism regulating inhibition of pre-T cell death. We characterize in detail the signaling pathway involved in A1 induction and show that A1 expression can induce pre-T cell survival by inhibiting activation of caspase-3. Moreover, we show that in vitro "knockdown" of A1 expression can compromise survival even in the presence of a functional pre-TCR. Finally, we suggest that pre-TCR-induced A1 overexpression can contribute to T cell leukemia in both mice and humans.
Discovery and Characterization of 2,5-Substituted Benzoic Acid Dual Inhibitors of the Anti-apoptotic Mcl-1 and Bfl-1 Proteins
JOURNAL OF MEDICINAL CHEMISTRY
Authors: Kump, Karson J.; Miao, Lei; Mady, Ahmed S. A.; Ansari, Nurul H.; Shrestha, Uttar K.; Yang, Yuting; Pal, Mohan; Liao, Chenzhong; Perdih, Andrej; Abulwerdi, Fardokht A.; Chinnaswamy, Krishnapriya; Meagher, Jennifer L.; Carlson, Jacob M.; Khanna, May; Stuckey, Jeanne A.; Nikolovska-Coleska, Zaneta
Abstract
Anti-apoptotic Bcl-2 family proteins are overexpressed in a wide spectrum of cancers and have become well validated therapeutic targets. Cancer cells display survival dependence on individual or subsets of anti-apoptotic proteins that could be effectively targeted by multimodal inhibitors. We designed a 2,5-substituted benzoic acid scaffold that displayed equipotent binding to Mcl-1 and Bfl-1. Structure-based design was guided by several solved cocrystal structures with Mcl-1, leading to the development of compound 24, which binds both Mcl-1 and Bfl-1 with K-i values of 100 nM and shows appreciable selectivity over Bcl-2/Bcl-xL. The selective binding profile of 24 was translated to on-target cellular activity in model lymphoma cell lines. These studies lay a foundation for developing more advanced dual Mcl-1/Bfl-1 inhibitors that have potential to provide greater single agent efficacy and broader coverage to combat resistance in several types of cancer than selective Mcl-1 inhibitors alone.