ACAT1 regulates tertiary lymphoid structures and correlates with immunotherapy response in non–small cell lung cancer
Mengxia Jiao, Yifan Guo, Hongyu Zhang, Haoyu Wen, Peng Chen, Zhiqiang Wang, Baichao Yu, Kameina Zhuma, Yuchen Zhang, Jingbo Qie, Yun Xing, Pengyuan Zhao, Zihe Pan, Luman Wang, Dan Zhang, Fei Li, Yijiu Ren, Chang Chen, Yiwei Chu, Jie Gu, Ronghua Liu
Mengxia Jiao, Yifan Guo, Hongyu Zhang, Haoyu Wen, Peng Chen, Zhiqiang Wang, Baichao Yu, Kameina Zhuma, Yuchen Zhang, Jingbo Qie, Yun Xing, Pengyuan Zhao, Zihe Pan, Luman Wang, Dan Zhang, Fei Li, Yijiu Ren, Chang Chen, Yiwei Chu, Jie Gu, Ronghua Liu
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Research Article Immunology Oncology

ACAT1 regulates tertiary lymphoid structures and correlates with immunotherapy response in non–small cell lung cancer

Abstract

Tertiary lymphoid structures (TLS) in the tumor microenvironment (TME) are emerging solid-tumor indicators of prognosis and response to immunotherapy. Considering that tumorigenesis requires metabolic reprogramming and subsequent TME remodeling, the discovery of TLS metabolic regulators is expected to produce immunotherapeutic targets. To identify such metabolic regulators, we constructed a metabolism-focused sgRNA library and performed an in vivo CRISPR screening in an orthotopic lung tumor mouse model. Combined with The Cancer Genome Atlas database analysis of TLS-related metabolic hub genes, we found that the loss of Acat1 in tumor cells sensitized tumors to anti-PD1 treatment, accompanied by increased TLS in the TME. Mechanistic studies revealed that ACAT1 resulted in mitochondrial protein hypersuccinylation in lung tumor cells and subsequently enhanced mitochondrial oxidative metabolism, which impeded TLS formation. Elimination of ROS by NAC or Acat1 knockdown promoted B cell aggregation and TLS construction. Consistently, data from tissue microassays of 305 patients with lung cancer showed that TLS were more abundant in non–small cell lung cancer (NSCLC) tissues with lower ACAT1 expression. Intratumoral ACAT1 expression was associated with poor immunotherapy outcomes in patients with NSCLC. In conclusion, our results identified ACAT1 as a metabolic regulator of TLS and a promising immunotherapeutic target in NSCLC.

Authors

Mengxia Jiao, Yifan Guo, Hongyu Zhang, Haoyu Wen, Peng Chen, Zhiqiang Wang, Baichao Yu, Kameina Zhuma, Yuchen Zhang, Jingbo Qie, Yun Xing, Pengyuan Zhao, Zihe Pan, Luman Wang, Dan Zhang, Fei Li, Yijiu Ren, Chang Chen, Yiwei Chu, Jie Gu, Ronghua Liu

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Figure 5

Mitochondrial ACAT1 targets display hypersuccinylation.

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Mitochondrial ACAT1 targets display hypersuccinylation. (A) Protein inte...
(A) Protein interaction and enrichment analysis of ACAT1. The protein-protein interaction network of ACAT1 was constructed by the STRING/Proteins Database. (B) IP and IB analyses were performed with the indicated antibodies. (C) Workflow of the proteomic and succinylation modification proteomic detection. (D) Pathway schematic showing proteins with upregulated succinylation sites (Wilcoxon test, FDR P < 0.05) mapped onto key metabolic pathways. (E–G) Mitochondria were extracted from carcinoma (T) and adjacent tissue (N) from lung cancer patients, and mitochondria lysates of the mitochondria were prepared. The total mitochondrial-protein succinylation levels were analyzed by IB with the indicated antibodies. A comparison of mitochondrial-protein succinylation modification levels (E) and ACAT1 expression level (F) between carcinoma (T) and adjacent tissue (N) in Supplemental Figure 4C, n = 10 per group. Paired t tests were performed. A correlation analysis between the ACAT1 levels and of mitochondrial-protein succinylation levels in Supplemental Figure 4C (G). (H) ACAT1-mediated HADHA succinylation was analyzed by mixing purified ACAT1, HADHA, and succinyl-CoA. Heat-inactived ACAT1 was used as a negative control. The succinylation level of HADHA was detected by IB. *P < 0.05; ***P < 0.001. Please also see Supplemental Figure 4.