Fra-2 controls the response to the KRAS inhibitor MRTX-1133 in pancreatic ductal adenocarcinoma

E Erika Testa (Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome) C Clara Dezi (Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome) F Francesca Lovat (Department of Cancer Biology and Genetics and Comprehensive Cancer Center, The Ohio State University) G Geny Piro (Department of Medical and Surgical Sciences, Fondazione Policlinico Universitario Agostino Gemelli Istituto di Ricovero e Cura a Carattere Scientifico) C Carmine Carbone M Marina Capece (Department of Cancer Biology and Genetics and Comprehensive Cancer Center, The Ohio State University) G Giovanni Nigita (Department of Cancer Biology and Genetics and Comprehensive Cancer Center, The Ohio State University) E Erisa Putro (Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome) E Elisabetta Di Renzi (Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome) A Alessandra Simeone (Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome) L Luca Reggiani Bonetti (Department of Diagnostic, Clinic and Public Health Medicine, University of Modena and Reggio Emilia) R Roberto Cirombella (Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome) P Paolo Magistri (Surgical, Medical and Dental Department of Morphological Sciences related to Transplant, Oncology and Regenerative Medicine, Hepato-Pancreato-Biliary Surgery and Liver Transplantation Unit, University of Modena and Reggio Emilia) V Vincenzo Corbo D Davide Pasini B Barbara Belletti (Division of Molecular Oncology, Centro di Riferimento Oncologico di Aviano, Istituto di Ricovero e Cura a Carattere Scientifico, National Cancer Institute) G Gustavo Baldassarre (Division of Molecular Oncology, Centro di Riferimento Oncologico di Aviano, Istituto di Ricovero e Cura a Carattere Scientifico, National Cancer Institute) A Andrea Vecchione (Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome) C Carlo M. Croce (Department of Cancer Biology and Genetics, Wexner Medical Center, College of Medicine, The Ohio State University Comprehensive Cancer Center) G Gian Luca Rampioni Vinciguerra (Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome)

Abstract

KRAS mutations are a hallmark of pancreatic ductal adenocarcinoma (PDAC), driving tumor initiation and progression in the vast majority of cases, with KRAS G12D being the most prevalent variant. Recent advances have led to the development of mutation-specific KRAS inhibitors (KRASi), yet their clinical impact is hindered by the rapid onset of drug resistance. In this study, we identify Fos-related antigen-2 (Fra-2), a stress-responsive transcription factor of the AP-1 family, as a key mediator of adaptive resistance to the KRAS G12D selective inhibitor MRTX-1133. Using a combination of established PDAC cell lines, xenograft models, and patient-derived organoids, we demonstrate that Fra-2 expression is consistently upregulated following MRTX-1133 treatment. Functional assays reveal that Fra-2 overexpression promotes resistance by reprogramming the transcriptional landscape, directly enhancing mTOR expression and signaling. Consistently, FRA2 and MTOR levels strongly correlate in PDAC patient samples. Collectively, these findings uncover a mechanistic interplay between Fra-2 and the mTOR pathway in MRTX-1133-resistant PDAC, highlighting that targeting Fra-2 may represent a valuable approach to enhance the efficacy of KRASi.

Article Details

Volume / Issue Vol. 123, Issue 18
Published May 05, 2026
ISSN 0027-8424
Publisher National Academy of Sciences

Authors (20)

E

Erika Testa

Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome

C

Clara Dezi

Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome

F

Francesca Lovat

Department of Cancer Biology and Genetics and Comprehensive Cancer Center, The Ohio State University

G

Geny Piro

Department of Medical and Surgical Sciences, Fondazione Policlinico Universitario Agostino Gemelli Istituto di Ricovero e Cura a Carattere Scientifico

C

Carmine Carbone

M

Marina Capece

Department of Cancer Biology and Genetics and Comprehensive Cancer Center, The Ohio State University

G

Giovanni Nigita

Department of Cancer Biology and Genetics and Comprehensive Cancer Center, The Ohio State University

E

Erisa Putro

Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome

E

Elisabetta Di Renzi

Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome

A

Alessandra Simeone

Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome

L

Luca Reggiani Bonetti

Department of Diagnostic, Clinic and Public Health Medicine, University of Modena and Reggio Emilia

R

Roberto Cirombella

Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome

P

Paolo Magistri

Surgical, Medical and Dental Department of Morphological Sciences related to Transplant, Oncology and Regenerative Medicine, Hepato-Pancreato-Biliary Surgery and Liver Transplantation Unit, University of Modena and Reggio Emilia

V

Vincenzo Corbo

D

Davide Pasini

B

Barbara Belletti

Division of Molecular Oncology, Centro di Riferimento Oncologico di Aviano, Istituto di Ricovero e Cura a Carattere Scientifico, National Cancer Institute

G

Gustavo Baldassarre

Division of Molecular Oncology, Centro di Riferimento Oncologico di Aviano, Istituto di Ricovero e Cura a Carattere Scientifico, National Cancer Institute

A

Andrea Vecchione

Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome

C

Carlo M. Croce

Department of Cancer Biology and Genetics, Wexner Medical Center, College of Medicine, The Ohio State University Comprehensive Cancer Center

G

Gian Luca Rampioni Vinciguerra

Department of Clinical and Molecular Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome