Using CETSA assay and a mathematical model to reveal dual Bcl-2/Mcl-1 inhibition and on-target mechanism for ABT-199 and S1

• Published in: European journal of pharmaceutical sciences Vol. 142; p. 105105
• Main Authors: Guo, Zongwei, Song, Ting, Xue, Zuguang, Liu, Peng, Zhang, Minhang, Zhang, Xiaodong, Zhang, Zhichao
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.01.2020
• Subjects: Bcl-2 family proteins; BH3 mimetics; CETSA; Mathematical modelling; CETSA; Bcl-2; MOMP; SPR; Abbreviations: CETSA; ODEs; ITC; Bcl-2 family proteins; Mathematical modelling; FP; BH3; BH3 mimetics
• ISSN: 0928-0987; 1879-0720
• DOI: 10.1016/j.ejps.2019.105105

Deepening understanding of how Bcl-2 family proteins protect cancer cells from apoptosis has driven the development of ‘BH3 mimetic’ drugs that target various anti-apoptotic Bcl-2-like proteins by mimicking their natural inhibitors, the BH3-only proteins. The proof of target engagement and an on-target mechanism validation are critical for evaluating drug development potential. To evaluate target engagement of BH3 mimetics in cells, we measured binding potency of ABT-199, A-1210477 and ABT-737 to Bcl-2 and Mcl-1 proteins by using a dose-response cellular thermal shift assay (CETSA), similar affinity rank-order and selectivity were obtained in comparison with in vitro binding assays. A proof of direct target engagement for S1 and AT-101 was obtained through CETSA assay. By using a previously established mathematical model, we simulated individual death response of various cancer cell lines to ABT-199, S1 or AT-101 in comparison with experimental data. A positive correlation between model predictions and experimental data for ABT-199 and S1 showed that dual Bcl-2 and Mcl-1 target engagement underlies their anticancer efficacy. In contrast, an off-target effect was determined for AT-101. [Display omitted]