A covalent molecular glue hijacks the E3 ligase MKRN2 to degrade the ribosomal protein RPS7 and induce synthetic lethality in p53-deficient NSCLC cells

IF 7.5 2区医学 Q1 PHARMACOLOGY & PHARMACY

British Journal of Pharmacology Pub Date : 2026-10-19 Epub Date: 2026-04-16 DOI:10.1111/bph.70434

Yuqi Pan, Shengjie Hua, Ruolan Yang, Qinman He, Yan Xu, Zeyu Jiang, Xiaoyang Gong, Shurui Zhang, Xiao Wang, Hongli Yu, Hao Wu, Hongmei Wen, Pin Wang, Bo Hang, Xinzhi Wang

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引用次数: 0

Abstract

Background and Purpose

Functional inactivation of the tumour suppressor p53 drives therapeutic resistance in non-small cell lung cancer (NSCLC). While targeted protein degradation offers a potential solution, the repertoire of ligandable E3 ligases remains limited. This study aimed to identify and characterise 2,6-didehydroxyspeperomin B (DPB) as a novel covalent molecular glue that targets p53-deficient NSCLC and to elucidate its mechanism of action involving the E3 ligase MKRN2.

Experimental Approach

Cytotoxicity of DPB was assessed in p53 wild-type and p53-deficient NSCLC cells and orthotopic mouse models. Direct cellular targets were identified using quantitative thiol-reactivity proteomics (QTRP) and validated via biophysical assays and site-directed mutagenesis. The molecular glue mechanism was mapped using co-immunoprecipitation-mass spectrometry and genetic knockout/rescue studies. Downstream effects on ribosome biogenesis and protein synthesis were quantified.

Key Results

DPB exhibited potent, selective cytotoxicity against p53-deficient NSCLC cells and suppressed tumour growth in vivo, outperforming standard chemotherapy. The E3 ubiquitin ligase MKRN2 was the direct target, with DPB covalently modifying the Cys335 residue. Mechanistically, DPB acted as a molecular glue, creating a neo-interface recruiting the ribosomal protein RPS7 to MKRN2. This induced ubiquitination and proteasomal degradation of RPS7, triggering acute nucleolar stress and apoptosis. The synthetic lethal effect was entirely dependent on a functional MKRN2–RPS7 axis.

Conclusion and Implications

Our findings identify DPB as a covalent molecular glue that harnesses the previously unexploited E3 ligase MKRN2 to eliminate p53-deficient cancer cells. This work validates the MKRN2–RPS7 axis as a synthetic lethal vulnerability and expands the E3 ligase toolbox for targeted protein degradation, providing a novel therapeutic strategy for drug-resistant NSCLC.

LINKED ARTICLES

This article is part of a themed issue Re-emergence of Covalent Modulation in Drug Discovery. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v183.22/issuetoc

查看原文本刊更多论文

共价分子胶劫持E3连接酶MKRN2，降解核糖体蛋白RPS7，诱导p53缺陷NSCLC细胞的合成致死。

背景与目的：肿瘤抑制因子p53的功能失活导致非小细胞肺癌（NSCLC）的治疗耐药。虽然靶向蛋白降解提供了一个潜在的解决方案，但可配体的E3连接酶仍然有限。本研究旨在鉴定和表征2,6-二dedehydroxyspeperomin B （DPB）作为一种针对p53缺陷NSCLC的新型共价分子胶，并阐明其涉及E3连接酶MKRN2的作用机制。实验方法：在p53野生型、p53缺失型非小细胞肺癌细胞和原位小鼠模型中评估DPB的细胞毒性。使用定量巯基反应性蛋白质组学（QTRP）鉴定直接细胞靶点，并通过生物物理试验和定点诱变进行验证。分子胶机制通过免疫沉淀-质谱和基因敲除/拯救研究进行了定位。对核糖体生物发生和蛋白质合成的下游影响进行了量化。关键结果：DPB对p53缺乏的NSCLC细胞表现出有效的选择性细胞毒性，并在体内抑制肿瘤生长，优于标准化疗。E3泛素连接酶MKRN2是直接靶标，DPB共价修饰Cys335残基。从机制上讲，DPB充当了分子胶，创造了一个新的界面，将核糖体蛋白RPS7招募到MKRN2上。这诱导了RPS7的泛素化和蛋白酶体降解，引发急性核核应激和细胞凋亡。合成致死效应完全依赖于功能性MKRN2-RPS7轴。结论和意义：我们的研究结果确定DPB是一种共价分子胶，利用以前未开发的E3连接酶MKRN2来消除p53缺陷的癌细胞。这项工作验证了MKRN2-RPS7轴是一个合成的致命易损，并扩展了E3连接酶工具箱用于靶向蛋白降解，为耐药NSCLC提供了一种新的治疗策略。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

British Journal of Pharmacology 医学-药学

CiteScore

15.40

自引率

12.30%

发文量

270

审稿时长

2.0 months

期刊介绍： The British Journal of Pharmacology (BJP) is a biomedical science journal offering comprehensive international coverage of experimental and translational pharmacology. It publishes original research, authoritative reviews, mini reviews, systematic reviews, meta-analyses, databases, letters to the Editor, and commentaries. Review articles, databases, systematic reviews, and meta-analyses are typically commissioned, but unsolicited contributions are also considered, either as standalone papers or part of themed issues. In addition to basic science research, BJP features translational pharmacology research, including proof-of-concept and early mechanistic studies in humans. While it generally does not publish first-in-man phase I studies or phase IIb, III, or IV studies, exceptions may be made under certain circumstances, particularly if results are combined with preclinical studies.