Promoter reinforcement supports transcriptional resilience in drug-resistant cancer

Our plain-English summary of Promoter reinforcement supports transcriptional resilience in drug-resistant cancer, by V. Kameswaran, S. Paul, D. Le, et al (Nature Structural & Molecular Biology, 2026).

The study

• Authors: V. Kameswaran, S. Paul, D. Le, A.D. Guarnaccia, J. Hoover, L.F. Chen, T.J. Hagenbeek, M. Shi, L.Y. Zhao, J.M. Lund, A. Xavier-Magalhães, J. Lau, M. De Simone, Y. Liang, A. Hafner, A. Dey, Z. Modrusan, B. Daniel
• Journal: Nature Structural & Molecular Biology
• Published: 2026;33(7):1051-1061
• Read it: PubMed · Publisher · Free full text

Abstract

In mammalian cells, gene-distal regulatory elements enable long-range gene regulation and support cell-type-specific transcriptional programs. This regulatory architecture is frequently perturbed in cancer, particularly when oncogenic transcription factors are targeted therapeutically. However, how cancer cells adapt under such selective pressure has remained poorly understood. Here we show that mesothelioma cells dependent on the oncogenic TEAD family of transcription factors acquire resistance to a pan-TEAD inhibitor. Such resistance is accompanied by a promoter-centric regulatory mechanism, a process we term promoter reinforcement, to sustain gene expression following TEAD inhibition. Using base-pair-resolution Micro Capture-C on a set of TEAD target genes, we find that regulatory element-promoter interactions are weakened or lost in resistant cells, even as promoter activity and gene expression recover in the context of partial epigenetic restoration. Mechanistically, resistance-induced transcription factors show promoter-biased localization and can increase promoter activity, whereas distal regulatory element function can become dispensable. Together, these findings identify promoter reinforcement as a locus-specific compensatory response that supports transcriptional resilience under TEAD inhibition, indicating promoter-associated vulnerabilities in drug-resistant cancer.

© 2026. The Author(s).

In plain English

This laboratory study used two human pleural mesothelioma cell lines, NCI-H226 and MSTO-211H, with Hippo-pathway defects; it studied drug resistance, not asbestos exposure or patients. The authors made the cells resistant to the pan-TEAD inhibitor GNE-7883 by raising the dose from 0.25 to 2.5 micromolar over about 55 days (H226) or 0.25 to 3.0 micromolar (MSTO). They compared vehicle-treated parental cells, parental cells treated for 48 hours, and resistant cells using RNA sequencing, ChIP-seq, ATAC-seq, CUT&RUN and Micro Capture-C. In H226 cells, 4,657 genes differed across conditions, falling into seven patterns, many returning to or exceeding parental levels in resistant cells. At targeted TEAD target-gene promoters (40 in H226, 50 in MSTO), the average contact signal at interacting distal regulatory elements fell in resistant cells, while promoter activity and expression recovered at selected loci. Deleting certain distal elements with CRISPR lowered expression in parental cells but had marginal or no effect in resistant cells. In H226 cells, KLF4 knockdown reduced expression of all 20 genes tested in a resistance-specific way and slowed growth of resistant but not parental cells.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: laboratory (in vitro) molecular study of cancer cell lines, using genomic and genome-editing experiments
• Who was studied: Two human malignant pleural mesothelioma cell lines (NCI-H226, NF2-null; MSTO-211H, with LATS1/LATS2 inactivation) obtained from ATCC; no human participants or animals
• Exposure: The pan-TEAD inhibitor GNE-7883: acute treatment (2.5 micromolar for 48 hours) and long-term dose escalation to generate resistant cells (H226: 0.25 to 2.5 micromolar over about 55 days; MSTO: 0.25 to 3.0 micromolar, with increases every 1 to 2 weeks). The authors also used CRISPR to delete promoters and regulatory elements and to knock down transcription factors.
• Main results:
  • In H226 cells, 4,657 genes were differentially expressed across the three conditions, forming seven expression clusters; clusters C5 (n = 800) returned to parental levels and C1 (n = 1,346) exceeded them in resistant cells
  • YAP chromatin binding in resistant cells: H226 showed 1,095 peaks with decreased and 4,780 with increased occupancy; MSTO showed 17,080 decreased and 8,658 increased
  • Micro Capture-C, targeting promoters of TEAD target genes plus control genes repressed in resistance (40 in H226, 50 in MSTO), identified 543 interacting regulatory-element peaks in H226 and 1,838 in MSTO. In both models, the average contact signal at these elements was reduced in resistant cells.
  • The authors interpreted reduced contact strength as coinciding with restored or increased promoter activity at selected loci, not at every targeted promoter
  • CRISPR deletion of the −15 kb regulatory element at FOSL1 lowered FOSL1 expression in parental cells of both models but had only marginal effects in resistant cells, while promoter deletion lowered expression in both states
  • In H226 cells, promoter-associated H3K4me3 was restored in resistant cells, whereas p300 and H3K27ac did not fully recover
  • In H226 cells, KLF4 knockdown reduced expression of all 20 measured genes in a resistance-specific way, and in resistant H226 cells it reduced promoter transcript levels by more than 50% at four loci
  • In H226 cells, loss of KLF4 slowed growth of resistant cells but not of parental cells
  • By DNA FISH, YAP1 copy number did not change in resistant H226 cells but increased about three-fold in resistant MSTO cells
• The authors' conclusion: The authors concluded that TEAD-inhibitor-resistant mesothelioma cells shift to promoter-centred gene regulation ('promoter reinforcement'), which sustains gene expression despite weakened regulatory element–promoter contacts.
• Limitations the authors state:
  • The authors note the work examined a defined set of TEAD-responsive loci, so broader applicability is only a possibility raised by the results
  • The authors state that the generality of the mechanism in other drug-resistant cancer models remains to be determined

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma.

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