Volume 250, July 2026, Pages 64-79Author links open overlay panel, , , , , , , , , , , Highlights•

Revealed the molecular mechanisms underlying the limited therapeutic benefit of EGFR inhibitors in breast cancer.

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Elucidated the critical role of TDP43 in regulating sensitivity and resistance to EGFR inhibitors.

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Screened and validated the potential application of the TDP43 inhibitor atovaquone in overcoming EGFR inhibitor resistance.

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Advanced the clinical application of TDP43 as a potential therapeutic target for TNBC.

Abstract

Epidermal growth factor receptor (EGFR) is overexpressed in most triple-negative breast cancer (TNBC) patients with poor prognosis; however, the therapeutic benefit of EGFR inhibitors (EGFRi) in breast cancer remains limited. In this study, we found poor response to EGFRi in TNBC was related to oxidative phosphorylation (OXPHOS) and breast cancer stem cells (BCSCs), and demonstrated that TDP43 (TAR DNA-binding protein 43) expression is positively correlated with non-response to EGFR tyrosine kinase inhibitors (EGFR-TKIs). TDP43 knockdown significantly enhances EGFR-TKI sensitivity and decreases EGFR-TKI resistance. Mechanistically, TDP43, a DNA/RNA-binding protein predominantly localized to the nucleus, translocates to mitochondria upon EGFR-TKI stimulation. The increased mitochondrial localization promotes OXPHOS, thereby enriching BCSCs and contributing to EGFR-TKI resistance. Inhibiting TDP43 expression or using our newly identified TDP43 inhibitor, atovaquone, suppresses OXPHOS and reduces EGFR-TKI resistance. Overall, our research identified TDP43 as a key regulator of EGFR-TKI sensitivity and resistance, and offers new therapeutic targets and promising application perspectives in TNBC.

Graphical abstractDownload: Download high-res image (274KB)Download: Download full-size imageKeywords

Triple-negative breast cancer

TDP43

Oxidative phosphorylation

EGFR inhibitor resistance

Breast cancer stem cells

Atovaquone

Data availabilityThe datasets presented in this study can be found in various online repositories. All raw RNA-seq data generated from this study can be accessed in the NGDC database under accession number HRA011521. Additional data related to this paper can be requested from the authors.

© 2026 The Authors. Published by Elsevier Inc.