Development and therapeutic potential of GSPT1 molecular glue degraders: A medicinal chemistry perspective.

Unprecedented therapeutic targeting of previously undruggable proteins has now been achieved by molecular-glue-mediated proximity-induced degradation. As a small GTPase, G1 to S phase transition 1 (GSPT1) interacts with eRF1, the translation termination factor, to facilitate the process of translation termination. Studied demonstrated that GSPT1 plays a vital role in the acute myeloid leukemia (AML) and MYC-driven lung cancer. Thus, molecular glue (MG) degraders targeting GSPT1 is a novel and promising approach for treating AML and MYC-driven cancers. In this Perspective, we briefly summarize the structural and functional aspects of GSPT1, highlighting the latest advances and challenges in MG degraders, as well as some representative patents. The structure-activity relationships, mechanism of action and pharmacokinetic features of MG degraders are emphasized to provide a comprehensive compendium on the rational design of GSPT1 MG degraders. We hope to provide an updated overview, and design guide for strategies targeting GSPT1 for the treatment of cancer.

Overview of the development of protein arginine methyltransferase modulators: Achievements and future directions.

Protein methylation is a post-translational modification (PTM) that organisms undergo. This process is considered a part of epigenetics research. In recent years, there has been an increasing interest in protein methylation, particularly histone methylation, as research has advanced. Methylation of histones is a dynamic process that is subject to fine control by histone methyltransferases and demethylases. In addition, many non-histone proteins also undergo methylation, and these modifications collectively regulate physiological phenomena, including RNA transcription, translation, signal transduction, DNA damage response, and cell cycle. Protein arginine methylation is a crucial aspect of protein methylation, which plays a significant role in regulating the cell cycle and repairing DNA. It is also linked to various diseases. Therefore, protein arginine methyltransferases (PRMTs) that are involved in this process have gained considerable attention as a potential therapeutic target for treating diseases. Several PRMT inhibitors are in phase I/II clinical trials. This paper aims to introduce the structure, biochemical functions, and bioactivity assays of PRMTs. Additionally, we will review the structure-function of currently popular PRMT inhibitors. Through the analysis of various data on known PRMT inhibitors, we hope to provide valuable assistance for future drug design and development.

Enhancing the affinity of novel GLS1 allosteric inhibitors by targeting key residue Lys320.

Aim: A series of novel GLS1 irreversible allosteric inhibitors targeting Lys320 might have robust enzyme inhibitory activity and potent antitumor activity. Materials & methods: Novel GLS1 allosteric inhibitors targeting Lys320 were synthesized and their anticancer activity was assessed. Moreover, GLS1 protein was used as a model system to analyze the reactivity of these electrophilic groups in GLS1 irreversible allosteric inhibitors with other amino acids, including tyrosine, histidine, serine and threonine, using biochemical and biophysical assays. Results: AC16 exhibited robust GLS1 inhibitory activity, antiproliferative effect in vitro, good plasma stability and potential covalent addition with GLS1 K320. Conclusion: This study opens a novel avenue for the design of robust irreversible GLS1 inhibitors targeting the allosteric site K320.

Discovery of thiohydantoin based antagonists of androgen receptor with efficient degradation for the treatment of prostate cancer.

Prostate cancer (PC) is one of the most prevalent cancers in men worldwide, and androgen receptor (AR) is a well-validated drug target for the treatment of PC. However, PC often exhibits resistance to AR antagonists over time. Thus, it is urgent to identify novel and effective drugs for PC treatment. A series of novel thiohydantoin based AR antagonists with efficient degradation against AR were designed, synthesized, and evaluated. Based on our previous SAR and further structural optimization, a tool molecule 26h was discovered with dual mechanisms including improved antagonistic activity and potent degradation (AR-fl and AR-V7). Moreover, 26h can also effectively block AR nuclear translocation and inhibit AR/AR-V7 heterodimerization, thereby inhibiting downstream gene transcription. Importantly, 26h displayed potent robust efficacy in LNCaP (TGI: 70.70%) and 22Rv1 (TGI: 78.89%) xenograft models. This provides new design strategies and advantageous potential compounds for the treatment of prostate cancer.

Design, synthesis, and biological evaluation of novel glutaminase 1 allosteric inhibitors with an alkane chain tail group.

Tumor cells often exhibit metabolic reprogramming to maintain their rapid growth and proliferation. Glutaminase 1 (GLS1) has been viewed as a promising target in the glutamine metabolism pathway for the treatment of malignant tumors. Using structure-based drug design approaches, a novel series of GLS1 allosteric inhibitors were designed and synthesized. Compound 41a (LWG-301) with an alkane chain "tail" group had potent biochemical and cellular GLS1 activity, and improved metabolic stability. LWG-301 exhibited moderate antitumor effects in HCT116 xenograft model, with TGI of 38.9% in vivo. Mechanistically, LWG-301 could significantly block glutamine metabolism, resulting in changes in the corresponding amino acid levels in cells, induce a concentration-dependent increase in intracellular ROS levels, and induce apoptosis. Taken together, this paper provides more structural references and new design strategy for the development of GLS1 allosteric inhibitors.

Discovery of novel glutaminase 1 allosteric inhibitor with 4-piperidinamine linker and aromatic heterocycles.

Glutaminase 1 (GLS1) is overexpressed in multiple types of malignant tumors and is viewed as a promising target in cancer therapy. Thus, the discovery for small-molecule GLS1 inhibitors is being urgent. Based on our previous study of C147, a potent GLS1 allosteric inhibitor yet with a limited metabolic stability, a structure-based optimization was carried out, with a series of novel GLS1 allosteric inhibitors rationally designed, synthesized and biologically evaluated. Such endeavor has culminated in the identification of 41e, a promising GLS1 allosteric inhibitor with 4-piperidinamine linker and aromatic heterocycles. 41e displayed robust GLS1 binding affinity, superior liver microsome metabolic stability, and moderate anti-tumor activity (TGI: 47.5%) in HCT116 xenograft model with no considerable toxicity in vivo. The mechanism underlying the anti-proliferative effect of 41e on HCT116 cells was studied, revealing that the compound blocked the glutamine metabolism, induced the production of ROS, and triggered apoptosis. These findings merit further investigation of 41e as a targeted cancer therapeutic.