Across biopharma, the pursuit and exploration of molecular glues continues unabated due their potential to transform our ability to modulate disease-relevant proteins. However, unlike traditional target-based drug discovery, where screening approaches require a focus on just one target, the rational identification of molecular glues requires innovative screening methods incorporating both target and effector.
WEE1 is a key regulator of the G2/M cell cycle checkpoint, and its inhibition or degradation has emerged as a promising strategy in oncology, particularly for tumors with defective p53 signaling or high replication stress. Targeting WEE1 can sensitize cancer cells to DNA-damaging agents and disrupt cell cycle progression, making it an attractive therapeutic target.1
In this presentation, we showcase two distinct approaches to WEE1 degradation. First, we explore the development of adavosertib-based PROTACs, aiming to enhance kinase selectivity by designing macrocyclic versions of the parent kinase inhibitor. The macrocyclic core of the novel adavosertib PROTACs was prepared on multigram scale using a ring-closing metathesis reaction, and was appended to a von Hippel-Lindau protein-binding fragment using diverse linker types, allowing a comparison of the analogs using KinaseProfiler assays. Finding poor kinase specificity, we transitioned to a molecular glue-based approach, using a novel high-throughput biophysical method based on Spectral Shift technology. This approach enabled the specific identification of a WEE1 molecular glue degrader through direct characterization of ternary complex formation between WEE1, cereblon, and a focused compound library, using a 1536-well plate format. The identified compound was subsequently validated through a series of orthogonal assays—including target-based, biophysical, and cellular approaches—and further characterized for its ability to degrade WEE1 in cells using Western blot and proteomics analyses. We believe that this innovative High-Throughput Spectral Shift platform, combined with a robust profiling strategy, offers a powerful tool for advancing molecular glue research and accelerating drug discovery in this emerging field.