Tescalcin is a phagocytic checkpoint driving immune escape and limiting immunotherapeutic efficacy in hepatocellular carcinoma
Jiong-Liang Wang, Jun-Cheng Wang, Yangxun Pan, Minrui He, Zhikai Zheng, Hao Zou, Tianqing Wu, Yuhan Zhang, Zili Hu, Yizhen Fu, Wei Peng, Zhenyun Yang, Li Xu, Yao-Jun Zhang, Min-Shan Chen, Dandan Hu, Jinbin Chen, Ming Zhao, Dong-Ping Chen, Zhong-Guo Zhou
Jiong-Liang Wang, Jun-Cheng Wang, Yangxun Pan, Minrui He, Zhikai Zheng, Hao Zou, Tianqing Wu, Yuhan Zhang, Zili Hu, Yizhen Fu, Wei Peng, Zhenyun Yang, Li Xu, Yao-Jun Zhang, Min-Shan Chen, Dandan Hu, Jinbin Chen, Ming Zhao, Dong-Ping Chen, Zhong-Guo Zhou
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Research Article Hepatology Immunology Oncology

Tescalcin is a phagocytic checkpoint driving immune escape and limiting immunotherapeutic efficacy in hepatocellular carcinoma

Abstract

Immunotherapies achieve durable responses in several cancers but show limited efficacy in refractory hepatocellular carcinoma (HCC). The mechanisms by which hepatoma cells evade immune recognition and limit immune checkpoint blockade (ICB) efficacy are incompletely defined. Here, we identified tumor-intrinsic tescalcin (TESC) as a previously unrecognized phagocytic checkpoint that contributes to immune evasion and ICB resistance in HCC. Mechanistically, H3K4 methylation drove TESC expression in hepatoma cells, facilitating cytosolic Ca2+ buffering and attenuating endoplasmic reticulum (ER) stress–induced calreticulin (CALR) plasma membrane exposure, an essential “eat-me” signal. Consequently, this process abrogated membrane CALR-directed phagocytosis by antigen-presenting cells (APCs), including macrophages and DCs, thereby impairing antigen presentation and subsequent T cell activation. Clinically, we found that elevated H3K4me3-TESC signaling was a promising prognostic biomarker for a poor ICB response in HCC. Importantly, in vivo disruption of this axis restored APC phagocytic function and enhanced the antitumor effects of ICB therapy. Therefore, targeting TESC-driven immune escape and its underlying epigenetic regulation may restore APC function and offer a precise therapeutic strategy to enhance immunotherapeutic efficacy in HCC.

Authors

Jiong-Liang Wang, Jun-Cheng Wang, Yangxun Pan, Minrui He, Zhikai Zheng, Hao Zou, Tianqing Wu, Yuhan Zhang, Zili Hu, Yizhen Fu, Wei Peng, Zhenyun Yang, Li Xu, Yao-Jun Zhang, Min-Shan Chen, Dandan Hu, Jinbin Chen, Ming Zhao, Dong-Ping Chen, Zhong-Guo Zhou

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Figure 4

TESC restrains CALR membrane translocation to inhibit macrophage function.

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TESC restrains CALR membrane translocation to inhibit macrophage functio...
(A) FACS analysis of GFP in BMDMs cultured with dead GFP-labeled shTesc H22 cells (n = 3). ****P < 0.0001, by 2-tailed Student’s t test. (B and C) BMDMs were cultured with dead shTesc H22 cells for 20 hours, followed by pHrodo Red FACS analysis and LysoTracker confocal imaging (n = 3). Scale bar: 10 μm. **P < 0.01 and ****P < 0.0001, by 2-tailed Student’s t test. (D) FACS analysis of H-2Kb–OVA complexes in BMDMs cultured with dead OVA-loaded shTesc H22 cells for 48 hours (n = 3). *P < 0.05, by 2-tailed Student’s t test. (E) Top 10 GO biological processes enriched in shTesc H22 cells by DIA-MS proteomics, with the top pathway involving CALR and TAP1. Fisher’s exact test was used to assess significance. (F) FACS analysis of pHrodo Red in BMDMs cultured with dead TAP1-silenced (shTap1)-transfected shTesc H22 cells (n = 3). ****P < 0.0001, by 1-way ANOVA. (G and H) FACS and confocal analysis of CALR expression in shTesc H22 cells (n = 3). Scale bar: 10 μm. **P < 0.01, by 2-tailed Student’s t test. (I) FACS analysis of pHrodo Red in BMDMs cultured with dead CALR-silenced (shCalr-transfected) shTesc H22 cells (n = 3). **P < 0.01 and ****P < 0.0001, by 1-way ANOVA. (J) FACS analysis of CALR expression in shTESC HepG2 cells (n = 3). ***P < 0.001, by 2-tailed Student’s t test. (K–M) FACS analysis of GFP, HLA-ABC, and HLA-DR in macrophages (MΦs) cultured with dead GFP-labeled shTESC HepG2 or TESC Huh7 cells (n = 3). *P < 0.05, **P < 0.01, and ***P < 0.001, by 2-tailed Student’s t test. (N and O) Functional analysis of OT-I cells cultured with dead OVA-loaded, shCalr-transfected shTesc H22 cells and macrophages for 3 days (n = 3). *P < 0.05 and **P < 0.01, by 1-way ANOVA. (P–R) Tumor size and CTL function were analyzed after inoculation of shCalr-transfected shTesc H22 cells (n = 5). *P < 0.05, **P < 0.01, and ***P < 0.001, by 1-way ANOVA. All data are presented as the mean ± SEM.