NOX4 Inhibition Potentiates Immunotherapy by Overcoming Cancer-Associated Fibroblast-Mediated CD8 T-cell Exclusion from Tumors



Ford, Kirsty, Hanley, Christopher J, Mellone, Massimiliano, Szyndralewiez, Cedric, Heitz, Freddy, Wiesel, Philippe, Wood, Oliver, Machado, Maria, Lopez, Maria-Antoinette, Ganesan, Anusha-Preethi
et al (show 9 more authors) (2020) NOX4 Inhibition Potentiates Immunotherapy by Overcoming Cancer-Associated Fibroblast-Mediated CD8 T-cell Exclusion from Tumors. CANCER RESEARCH, 80 (9). pp. 1846-1860.

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Abstract

Determining mechanisms of resistance to αPD-1/PD-L1 immune-checkpoint immunotherapy is key to developing new treatment strategies. Cancer-associated fibroblasts (CAF) have many tumor-promoting functions and promote immune evasion through multiple mechanisms, but as yet, no CAF-specific inhibitors are clinically available. Here we generated CAF-rich murine tumor models (TC1, MC38, and 4T1) to investigate how CAFs influence the immune microenvironment and affect response to different immunotherapy modalities [anticancer vaccination, TC1 (HPV E7 DNA vaccine), αPD-1, and MC38] and found that CAFs broadly suppressed response by specifically excluding CD8<sup>+</sup> T cells from tumors (not CD4<sup>+</sup> T cells or macrophages); CD8<sup>+</sup> T-cell exclusion was similarly present in CAF-rich human tumors. RNA sequencing of CD8<sup>+</sup> T cells from CAF-rich murine tumors and immunochemistry analysis of human tumors identified significant upregulation of CTLA-4 in the absence of other exhaustion markers; inhibiting CTLA-4 with a nondepleting antibody overcame the CD8<sup>+</sup> T-cell exclusion effect without affecting Tregs. We then examined the potential for CAF targeting, focusing on the ROS-producing enzyme NOX4, which is upregulated by CAF in many human cancers, and compared this with TGFβ1 inhibition, a key regulator of the CAF phenotype. siRNA knockdown or pharmacologic inhibition [GKT137831 (Setanaxib)] of NOX4 "normalized" CAF to a quiescent phenotype and promoted intratumoral CD8<sup>+</sup> T-cell infiltration, overcoming the exclusion effect; TGFβ1 inhibition could prevent, but not reverse, CAF differentiation. Finally, NOX4 inhibition restored immunotherapy response in CAF-rich tumors. These findings demonstrate that CAF-mediated immunotherapy resistance can be effectively overcome through NOX4 inhibition and could improve outcome in a broad range of cancers. SIGNIFICANCE: NOX4 is critical for maintaining the immune-suppressive CAF phenotype in tumors. Pharmacologic inhibition of NOX4 potentiates immunotherapy by overcoming CAF-mediated CD8<sup>+</sup> T-cell exclusion. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/9/1846/F1.large.jpg.<i>See related commentary by Hayward, p. 1799</i>.

Item Type: Article
Uncontrolled Keywords: CD8-Positive T-Lymphocytes, Cell Line, Tumor, Animals, Humans, Mice, Neoplasms, Reactive Oxygen Species, Immunotherapy, Cancer-Associated Fibroblasts, NADPH Oxidase 4
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Institute of Systems, Molecular and Integrative Biology
Depositing User: Symplectic Admin
Date Deposited: 15 Jul 2021 09:01
Last Modified: 18 Jan 2023 23:39
DOI: 10.1158/0008-5472.CAN-19-3158
Open Access URL: https://eprints.soton.ac.uk/438433/
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3095444