Abstract LB-236: Design, synthesis, and assessment of anticancer properties of pyrazolopyrimidine derivatives as Glycogen Synthase Kinase-3β inhibitors

Glycogen synthase kinase-3β (GSK-3β) is a serine/threonine kinase with a crucial role in several key cellular functions including tumor cell proliferation and survival. Yet, GSK-3β has emerged as an attractive target for the development of anti-cancer agents. Several small-molecule have been developed as GSK-3β inhibitors. Amongst, several pyrazolopyrimidines based ATP-competitive inhibitors were identified as promising GSK-3β inhibitors. In this work, several pyrazolo[3,4-d]pyrimidine derivatives were designed, synthesized and assessed for their potential anticancer activity. The new compounds are categorized under two templates, Template A and Template B. In these templates two different linkers with varying lengths and electronic properties were used to link additional aromatic ring systems to the core pyrazolopyrimidine scaffold. The aromatic ring systems were designed with different electronic and bonding properties to test their GSK-3β inhibitory activity and consequently their anticancer properties. All compounds under investigation showed GSK-3β inhibitory properties with IC509s ranging from 0.17- 1.01 µM compared to Tideglusib (standard GSK-3β inhibitor) which showed IC50 of 0.22 µM. Furthermore, the compounds were tested for their potential cytotoxicity against two breast cancer cells (MCF-7 and MDA-MB-231) and lung cancer cells (A549). Only one compound from Template B which possesses the longer hydrazide linker and 2,3-dihydroxy phenyl aromatic ring (compound 27), showed considerable cytotoxic effects against MCF-7, MDA-MB-231 and A549 cells (IC509s of 2.4, 2.4 and 2.3 µM, respectively). Compounds 21, 24, 25 and 26 showed weaker cytotoxic effects against cell lines under investigation (IC509s ranged from 29 to 93 µM). DNA content flow-cytometry analysis was undertaken to evaluate the potential effects of compound 27 on the cell cycle distribution of cell lines under investigation. Compound 27 induced significant antiproliferative effect and accumulation of cells in G0/G1-phase after 24 h of exposure. Longer exposure (48 h) to compound 27 resulted in cell cycle arrest in G2/M-phase. Additional assessment for programmed/non-programed cell death using annexin-V/FITC and acridine orange staining coupled with flow-cytometric analysis showed the ability of compound 27 to induce apoptosis as well as autophagy in all cells under investigation. In conclusion, compound 27 represents a promising GSK-3β inhibitor with potential anticancer properties via the induction of cell cycle arrest with subsequent cellular stress and induction of apoptosis and autophagy. Citation Format: Ahmed T. Negmeldin, Mohammed K. AbdElhameid, Dalia Y. Alsaeedy, Fatiha Hammed, Rasha M. Allam, Walid El-Sayed, Ahmed M. Al-Abd. Design, synthesis, and assessment of anticancer properties of pyrazolopyrimidine derivatives as Glycogen Synthase Kinase-3β inhibitors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-236.