HO-1 impairs the efficacy of radiotherapy by redistributing cGAS and STING in tumors
Chuqing Zhang, … , Cheng Xu, Xiaoyu Liang
Chuqing Zhang, … , Cheng Xu, Xiaoyu Liang
Published December 2, 2024
Citation Information: J Clin Invest. 2024;134(23):e181044. https://doi.org/10.1172/JCI181044.
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Research Article Immunology Oncology

HO-1 impairs the efficacy of radiotherapy by redistributing cGAS and STING in tumors

Abstract

Type I IFNs (IFN-Is) induced by radiotherapy (RT) are critical for its efficacy, while the mechanism by which tumor cells inhibit IFN-I production remains largely unsolved. By an unbiased CRISPR screen, we identified hemeoxygenase 1 (HO-1) as an RT-related regulator of IFN-I production. Mechanistically, the ER-anchored, full-length HO-1 disrupted stimulator of IFN genes (STING) polymerization and subsequent coat protein complex II–mediated (COPII-mediated) ER-Golgi transportation, leading to hampered activation of downstream signaling. This process was exacerbated by the upregulation of HO-1 expression under RT. Importantly, RT also induced HO-1 cleavage. Cleaved HO-1 underwent nuclear translocation, interacted with cyclic GMP-AMP synthase (cGAS), and inhibited its nuclear export upon irradiation, leading to suppressed 2′3′-cyclic GMP-AMP (cGAMP) production. Furthermore, we revealed that HO-1 inhibitors could enhance local and distant tumor control of RT in vivo. Clinically, higher HO-1 expression was associated with a poorer prognosis and earlier tumor relapse after RT in multiple types of patient tumors. Collectively, through comprehensive inhibition of the cGAS/STING pathway, HO-1 strongly inhibited RT-induced IFN-I production, and targeting HO-1 was shown to be a promising RT-sensitizing therapeutic strategy.

Authors

Chuqing Zhang, Zhenji Deng, Jiawei Wu, Cong Ding, Zhe Li, Zhimin Xu, Weipeng Chen, Kaibin Yang, Hanmiao Wei, Tingxiang He, Liufen Long, Jun Ma, Cheng Xu, Xiaoyu Liang

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Figure 1

A metabolic CRISPR/Cas9 screen identifies HO-1 as a potent IFN-I production inhibitor in response to RT.

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A metabolic CRISPR/Cas9 screen identifies HO-1 as a potent IFN-I product...
(A) Schematic overview of the mCherry reporter construct. mCherry expression is driven by ISREs followed by the IFN-β promoter. (B) Control HK1 cells and IRF3-KO HK1 cells were stimulated with radiation, cGAMP (10 μM), or IFN-β (100 ng/mL). mCherry reporter expression was further analyzed by flow cytometry. (C) Overview of the CRISPR screen. Reporter-expressing HK1 cells were transduced with the sgRNA library. After radiation, the cells were sorted by flow cytometer according to mCherry expression and divided into the highest 30% and the lowest 30% mCherry-expressing populations. Genomic DNA from the sorted cells was deep sequenced to reveal gRNA enrichment. (D) Distribution of the RRA score of the top hits enriched in the mCherry high expression group versus the low expression group. (E) Volcano plot illustrating the important candidates based on the comparison of high mCherry-expressing group versus the low mCherry-expressing group. P-adj, adjusted P value. (F–H) Reporter expression (F), HLAA (G), and CXCL10 (H) mRNA levels after knocking down the top 10 candidates in a post-RT CRISPR screen. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001, by 1-way ANOVA (B and F–H). Data are shown as the mean ± SD (n = 3 biologically independent samples).