FGFR inhibitors promote the autophagic degradation of IFN-γ-induced PD-L1 and alleviate the PD-L1-mediated transcriptional suppression of FGFR3-TACC3 in non-muscle-invasive bladder cancer

Abstract Bladder cancer (BC) is the second most prevalent genitourinary malignancy worldwide. Treatment options remain limited for patients with Bacillus Calmette–Guérin (BCG)-unresponsive non-muscle-invasive bladder cancer (NMIBC). Up to 70% of NMIBC cases harbor fibroblast growth factor receptor 3...

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Main Authors: Yu-Chen Lin, Cheng-Ying Chu, Tsung-Han Hsieh, Bo-Jyun Lin, Jing-Ping Liou, Yun Yen, Chun-Han Chen
Format: Article
Language:English
Published: Nature Publishing Group 2025-07-01
Series:Cell Death and Disease
Online Access:https://doi.org/10.1038/s41419-025-07821-8
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author Yu-Chen Lin
Cheng-Ying Chu
Tsung-Han Hsieh
Bo-Jyun Lin
Jing-Ping Liou
Yun Yen
Chun-Han Chen
author_facet Yu-Chen Lin
Cheng-Ying Chu
Tsung-Han Hsieh
Bo-Jyun Lin
Jing-Ping Liou
Yun Yen
Chun-Han Chen
author_sort Yu-Chen Lin
collection DOAJ
description Abstract Bladder cancer (BC) is the second most prevalent genitourinary malignancy worldwide. Treatment options remain limited for patients with Bacillus Calmette–Guérin (BCG)-unresponsive non-muscle-invasive bladder cancer (NMIBC). Up to 70% of NMIBC cases harbor fibroblast growth factor receptor 3 (FGFR3) alterations, and FGFR inhibition has shown potential to enhance the efficacy of immune checkpoint inhibitor (ICI). Interferon (IFN)-γ, a cytokine produced by activated T cells and associated with better response to immunotherapy in BC, is a key inducer of PD-L1 expression in the tumor microenvironment. However, the interaction between FGFR inhibitors and IFN-γ-induced PD-L1 expression in FGFR3-activated NMIBC cells remains unclear. Here, we show that FGFR inhibitors significantly reduced IFN-γ-induced PD-L1 expression in NMIBC cells harboring FGFR3-TACC3 fusions. Mechanistically, FGFR inhibitors restored IFN-γ-suppressed SIRT1 expression, promoted LC3B deacetylation and nuclear export, and enhanced autophagy-lysosomal degradation of PD-L1. Blocking autophagy, overexpression SIGMAR1, or inhibiting lysosomal activity significantly reversed PD-L1 degradation. Notably, we demonstrate for the first time that IFN-γ-induced PD-L1 directly binds to the FGFR3 promoter and represses FGFR3-TACC3 transcription–an effect that can be rescued by FGFR inhibitors or PD-L1 knockdown. Functionally, FGFR inhibitors ameliorated PD1/PD-L1-mediated T cell suppression in co-culture assays. Together, these findings highlight a novel mechanism by which FGFR inhibitors suppress IFN-γ-induced PD-L1 via autophagy and suggest a potential strategy to improve ICI therapy in FGFR3-altered NMIBC.
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spelling doaj-art-d0399b1f93334fb4b4b1c9f9d8ca26e02025-08-20T03:45:38ZengNature Publishing GroupCell Death and Disease2041-48892025-07-0116111510.1038/s41419-025-07821-8FGFR inhibitors promote the autophagic degradation of IFN-γ-induced PD-L1 and alleviate the PD-L1-mediated transcriptional suppression of FGFR3-TACC3 in non-muscle-invasive bladder cancerYu-Chen Lin0Cheng-Ying Chu1Tsung-Han Hsieh2Bo-Jyun Lin3Jing-Ping Liou4Yun Yen5Chun-Han Chen6Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical UniversityCRISPR Gene Targeting Core, Taipei Medical UniversityPrecision Health Center, Taipei Medical UniversityGraduate Institute of Medical Sciences, College of Medicine, Taipei Medical UniversitySchool of Pharmacy, College of Pharmacy, Taipei Medical UniversityPh.D. Program for Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical UniversityGraduate Institute of Medical Sciences, College of Medicine, Taipei Medical UniversityAbstract Bladder cancer (BC) is the second most prevalent genitourinary malignancy worldwide. Treatment options remain limited for patients with Bacillus Calmette–Guérin (BCG)-unresponsive non-muscle-invasive bladder cancer (NMIBC). Up to 70% of NMIBC cases harbor fibroblast growth factor receptor 3 (FGFR3) alterations, and FGFR inhibition has shown potential to enhance the efficacy of immune checkpoint inhibitor (ICI). Interferon (IFN)-γ, a cytokine produced by activated T cells and associated with better response to immunotherapy in BC, is a key inducer of PD-L1 expression in the tumor microenvironment. However, the interaction between FGFR inhibitors and IFN-γ-induced PD-L1 expression in FGFR3-activated NMIBC cells remains unclear. Here, we show that FGFR inhibitors significantly reduced IFN-γ-induced PD-L1 expression in NMIBC cells harboring FGFR3-TACC3 fusions. Mechanistically, FGFR inhibitors restored IFN-γ-suppressed SIRT1 expression, promoted LC3B deacetylation and nuclear export, and enhanced autophagy-lysosomal degradation of PD-L1. Blocking autophagy, overexpression SIGMAR1, or inhibiting lysosomal activity significantly reversed PD-L1 degradation. Notably, we demonstrate for the first time that IFN-γ-induced PD-L1 directly binds to the FGFR3 promoter and represses FGFR3-TACC3 transcription–an effect that can be rescued by FGFR inhibitors or PD-L1 knockdown. Functionally, FGFR inhibitors ameliorated PD1/PD-L1-mediated T cell suppression in co-culture assays. Together, these findings highlight a novel mechanism by which FGFR inhibitors suppress IFN-γ-induced PD-L1 via autophagy and suggest a potential strategy to improve ICI therapy in FGFR3-altered NMIBC.https://doi.org/10.1038/s41419-025-07821-8
spellingShingle Yu-Chen Lin
Cheng-Ying Chu
Tsung-Han Hsieh
Bo-Jyun Lin
Jing-Ping Liou
Yun Yen
Chun-Han Chen
FGFR inhibitors promote the autophagic degradation of IFN-γ-induced PD-L1 and alleviate the PD-L1-mediated transcriptional suppression of FGFR3-TACC3 in non-muscle-invasive bladder cancer
Cell Death and Disease
title FGFR inhibitors promote the autophagic degradation of IFN-γ-induced PD-L1 and alleviate the PD-L1-mediated transcriptional suppression of FGFR3-TACC3 in non-muscle-invasive bladder cancer
title_full FGFR inhibitors promote the autophagic degradation of IFN-γ-induced PD-L1 and alleviate the PD-L1-mediated transcriptional suppression of FGFR3-TACC3 in non-muscle-invasive bladder cancer
title_fullStr FGFR inhibitors promote the autophagic degradation of IFN-γ-induced PD-L1 and alleviate the PD-L1-mediated transcriptional suppression of FGFR3-TACC3 in non-muscle-invasive bladder cancer
title_full_unstemmed FGFR inhibitors promote the autophagic degradation of IFN-γ-induced PD-L1 and alleviate the PD-L1-mediated transcriptional suppression of FGFR3-TACC3 in non-muscle-invasive bladder cancer
title_short FGFR inhibitors promote the autophagic degradation of IFN-γ-induced PD-L1 and alleviate the PD-L1-mediated transcriptional suppression of FGFR3-TACC3 in non-muscle-invasive bladder cancer
title_sort fgfr inhibitors promote the autophagic degradation of ifn γ induced pd l1 and alleviate the pd l1 mediated transcriptional suppression of fgfr3 tacc3 in non muscle invasive bladder cancer
url https://doi.org/10.1038/s41419-025-07821-8
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