Molecular editing, rooted in synthetic chemistry, has emerged as a powerful tool for structure optimization in medicinal chemistry but remains underutilized in targeted protein degradation. Here, we demonstrate the utility of molecular editing by repurposing the NSD2 degrader LLC0424 with GSPT1 neosubstrate engagement to generate two structurally analogous molecules with divergent modes of action: 424-ND, a PROTAC selective for NSD2, and 424-GD, a selective GSPT1 molecular glue. 424-ND drove NSD2 degradation selectively in a CRBN- and proteasome-dependent manner and functionally suppressed androgen receptor (AR) signaling in prostate cancer cells. 424-GD induced selective degradation of GSPT1 and robustly upregulated the integrated stress response markers ATF4 and ATF3. Biolayer interferometry revealed distinct ternary complex cooperativity profiles in the presence of NSD2 or GSPT1, which directly correlate with the observed biased degradation activity. Further molecular dynamics and metadynamics simulations showed that the compounds adopt distinct low-energy conformational ensembles with different spatial orientations, likely underlying their divergent cooperativity and selectivity. These findings not only deliver highly selective chemical probes for NSD2 and GSPT1 but also demonstrate that molecular editing enables precision control over target selectivity, providing a generalizable strategy to tune selectivity in targeted protein degradation. Table of Contents Graphic
Wei-Zhong Shen, Yi-Han Liu, Lian-Chao Liu et al.· bioRxiv· 0 citations
Lineage plasticity, or transdifferentiation, is increasingly recognized as a resistance mechanism to androgen receptor (AR) inhibition in prostate cancer. Lineage plasticity is characterized by loss of AR signaling and epithelial differentiation, along with activation of stemness-associated pathways, epithelial-mesenchymal transition (EMT), or alternative differentiation programs such as neuroendocrine prostate cancer (NEPC). Loss of the tumor suppressors TP53 and RB1 is common in tumors exhibiting lineage plasticity; however, mechanisms by which TP53/RB1 loss promotes this phenotype remain poorly understood, and effective treatments are limited. Using multi-omic profiling of TP53/RB1 loss prostate cancer models, we identified alterations in chromatin accessibility, DNA methylation, and gene expression associated with lineage plasticity. Importantly, many pathways activated upon TP53/RB1 loss could be blocked through BET bromodomain inhibition. TP53/RB1-deficient cells also harbored widespread DNA methylation changes that silenced pathways linked with restraining lineage plasticity. Combined BET bromodomain and DNA methyltransferase (DNMT) inhibition was more effective than single agent treatment in suppressing growth of TP53/RB1 loss models exhibiting a stem-like or NEPC program. This was partly explained by abrogation of discrete lineage plasticity pathways modulated by each agent. Altogether, our work suggests combined BET bromodomain and DNMT inhibition is a promising therapeutic approach for prostate tumors exhibiting lineage plasticity.
W. Storck, Diana Flores, A. Kumaraswamy et al.· JCI Insight· 0 citations
Summary Neuroendocrine prostate cancer (NEPC) persists in a profoundly hypoxic microenvironment, yet the mechanisms enabling tumor adaptation to this metabolically challenging niche remain undefined. Here, we identify the lipid kinase PIKfyve as overexpressed in NEPC, functioning as a central node in a stress-adaptive lipid kinase axis that supports adaptation to persistent endoplasmic reticulum (ER) stress. Mechanistically, NEPC requires PIKfyve-mediated lysosomal degradation and lipid recycling to maintain metabolic homeostasis under hypoxia. PIKfyve inhibition disrupts lysosomal function, exacerbates ER stress, and activates a compensatory sterol regulatory element-binding protein (SREBP)-dependent de novo lipogenesis program essential for NEPC survival. This stress-lipid axis creates a synthetic vulnerability between PIKfyve and fatty acid synthase (FASN), where dual inhibition synergistically amplifies ER stress, triggers the terminal unfolded protein response, and induces tumor cell death. These findings reveal a metabolic adaptation in NEPC and provide preclinical evidence that co-targeting PIKfyve and FASN can overcome hypoxia-associated stress adaptation.
Yang Zheng, Caleb Cheng, Yizhi Cao et al.· Cancer Cell· 0 citations
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