Abstract 3107: Development of novel JAK2 inhibitors and PROTACs as chemical probes for the investigation of JAK2 inhibition and degradation

Abstract Inhibition and, more recently, degradation of protein kinases is an important therapeutic strategy to modulate disregulated signaling pathways in the cell cycle. Janus kinase 2 (JAK2) is a protein kinase involved in the JAK/STAT pathway which is one of the 12 core cancer pathways; thus, the regulation of JAK2 is important in the maintenance of normal cell function. A fragment-based drug discovery approach was taken to synthesize novel JAK2 inhibitors based using building blocks suitable for PROTAC development. Small molecule inhibitors were analyzed through computational analysis to probe the binding interactions in the hinge region of the ATP active site of JAK2. PROTACs were designed to investigate the degradation of JAK2 based on small molecule ligands with high binding affinity to JAK2. Pyrrolopyrimidine and pyrimidine scaffolds were used to probe the hydrogen bonding interactions in the hinge region to investigate binding affinity. Modification of A-ring and B-ring fragments of the inhibitors and PROTACs were used to develop SAR through data obtained by functional assays, including differential scanning fluorimetry and 33P HotSpot™ kinase assay, in addition to in-vivo cell viability assays as models for myeloproliferative neoplasms. Several key pyrrolopyrimidine and pyrimidine core containing inhibitors and PROTACs bind strongly to JAK2 and modulate JAK2 activity in appropriate cancer cell lines. Citation Format: Briley A. Humphrey, Bao li, Renan B. Ferreira, Sujeewa R. Ranatunga, Tegan M. Rowsell, Luxin Sun, Harshani R. Lawrence, Ernst Schonbrunn, Gary Reuther, Nicholas J. Lawrence. Development of novel JAK2 inhibitors and PROTACs as chemical probes for the investigation of JAK2 inhibition and degradation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3107.