EGFR inhibitor-resistant lung cancers exhibit collateral sensitivity to a covalent, cysteine-independent KEAP1 oligomerizing molecular bridge

Sep 22, 2026

EGFR inhibitor-resistant EGFR-mutant non-small cell lung cancer cells gain hypersensitivity to a PAINS-like small molecule, MCB-613, revealing a collateral sensitivity mechanism induced by resistance evolution. Proteomic, genomic, and biochemical analyses show MCB-613 covalently binds KEAP1 in a cysteine-independent manner and uses lysine residues in the KEAP1 dimerization domain to bridge KEAP1 monomers, driving KEAP1 oligomerization. This triggers KEAP1 dysfunction, ROS accumulation, and ATF4/CHOP-dependent cell death, linking resistance models through elevated integrated stress response activity and enabling selection against resistance evolution via non-canonical KEAP1–ATF4 signaling.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages20

Reading Time50 min

AccessFree to download

Background: drug resistance and multifocal resistance

Need for collateral vulnerabilities

Core findings: collateral sensitivity in EGFR-mutant NSCLC

MCB-613 targets KEAP1 via covalent cysteine-independent bridging

Downstream pathway: KEAP1 dysfunction, ROS, and ATF4/CHOP-dependent death

Implications: guiding tumor evolution away from resistance

Article [https://doi.org/10.1038/s41467-026-68424-](https://doi.org/10.1038/s41467-026-68424-) EGFR inhibitor-resistant lung cancers exhibit collateral sensitivity to a covalent, cysteineindependent KEAP1 oligomerizing molecular bridge Received: 14 January 2025 | Accepted: 2 January 2026 | | --- | | | | Check for updates | Christopher F. Bassil 1, Kerry Dillon1, Gray R. Anderson1, Benjamin Mayro1, Kayleigh N. Askin1, Peter S. Winter1, Stefan Harry2, Samuel Gruber1, Tierney M. Hall1, Jacob P. Hoj 1, Christian Cerda-Smith 1, Haley M. Hutchinson 1, Shane T. Killarney 1, Ava Heffernan1, Caroline Teddy1, Katherine R. Singleton1, Li Qin 3, Kévin Jubien-Girard4, Cécile Favreau5, Guillaume Robert 5, Barr Tivon6, Ella Livnah6, Nir London6, Rachid Benhida4,7, Patrick Auberger5, Ann Marie Pendergast1, Liron Bar-Peled 2, David M. Lonard 3, Anthony R. Martin 4,8, Alexandre Puissant 9 & Kris C. Wood 1 Targeted therapies have revolutionized cancer care. Unfortunately, most patients develop refractory, multifocal resistance to these therapies within a matter of months. Here, we demonstrate that the evolution of resistance to EGFR inhibitors in EGFR-mutant non-small cell lung cancer endows cells with hypersensitivity to a PAINS-like small molecule, MCB-613. Systematic proteomic, functional genomic, and biochemical studies revealed that MCB-613 binds KEAP1 in a covalent, cysteine-independent fashion, acting as a divalent molecular bridge that relies upon lysine residues in the KEAP1 dimerization domain to join monomers of KEAP1 together. Oligomerization of KEAP1 by MCB-613 sets into motion a fatal cascade of KEAP1 dysfunction, ROS accumulation, and ATF4/CHOP-dependent cell death. Together, these ﬁndings demonstrate that diverse models of EGFR inhibitor-resistant NSCLC share the common feature of elevated integrated stress response activity, and that a covalent molecular bridge which activates non-canonical KEAP1-ATF4 signaling can exploit this feature to select against resistance evolution. Although the use of targeted therapies to treat cancer has resulted in encouraging clinical responses, these beneﬁts are, unfortunately, often short-lived. In the case of non-small cell lung cancers (NSCLC) driven by activating mutations in the epidermal growth factor receptor (EGFR), for instance, most patients will develop resistance to ﬁrst-line targeted therapy within 24 months1,2. This problem is complicated by two interrelated considerations: (1) EGFR-mutant NSCLC cells can mechanisms; and, (2) these mechanisms can coevolve simultaneously in the same patient or tumor3. This presents clinicians and researchers with a difﬁcult quandary: on the one hand, treatments which use one drug to target an individual resistance mechanism are insufﬁcient and 1 develop resistance toEGFR inhibitors through a wide variety ofdistinct unlikely to prove curative; on the other hand, treatments which use multiple drugs to target many different mechanisms at the same time A full list of afﬁliations appears at the end of the paper. e-mail: [kris.wood@duke.edu](kris.wood@duke.edu) are demanding, and in many cases infeasible. Thus, new approaches to the problem of “multifocal” drug resistance are needed. One strategy is to identify, target, and exploit vulnerabilities which emerge as a consequence of drug resistance itself. These acquired, or “collateral,” sensitivities—which are distinct from chemical synthetic lethalities in that they persist even after removal of the original, selecting drug—have long been documented in the microbial literature4. Recently, for instance, it was shown that clinical isolates taken from the lungs of cystic ﬁbrosis patients suffering from chronic, drug-resistant Pseudomonas aeruginosa infections consistently harbored mutations in the nfxB gene5. These mutations, though pathoadaptive in the setting of conventional anti-pseudomonal therapy with ﬂuoroquinolones, nevertheless render bacterial populations collaterall

FAQs

What collateral sensitivity is observed in EGFR inhibitor-resistant NSCLC cells?

Resistance to EGFR inhibitors endows EGFR-mutant non-small cell lung cancer cells with hypersensitivity to the PAINS-like small molecule MCB-613.

How does MCB-613 interact with KEAP1?

MCB-613 covalently binds KEAP1 in a cysteine-independent fashion and acts as a divalent molecular bridge using lysine residues in the KEAP1 dimerization domain to join KEAP1 monomers.

What cellular events lead to ATF4/CHOP-dependent cell death?

KEAP1 oligomerization by MCB-613 initiates KEAP1 dysfunction, causes ROS accumulation, and activates an ATF4/CHOP-dependent cell death program.

Sep 22, 2026

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