Pharmacological activation of STAT1-GSDME pyroptotic circuitry reinforces epigenetic immunotherapy for hepatocellular carcinoma
Yalin Tu, Haoran Wu, Chengpeng Zhong, Yan Liu, Zhewen Xiong, Siyun Chen, Jing Wang, Patrick Pak-Chun Wong, Weiqin Yang, Zhixian Liang, Jiahuan Lu, Shufen Chen, Lingyun Zhang, Yu Feng, Willis Wai-Yiu Si-Tou, Baoyi Yin, Yingnan Lin, Jianxin Liang, Liying Liang, Joaquim S. L. Vong, Weida Ren, Tsz Tung Kwong, Howard H.W. Leung, Ka‐Fai To, Stephanie Ma, Man Tong, Hanyong Sun, Qiang Xia, Jingying Zhou, Rachel Kerr, Nick La Thangue, Joseph J.�Y. Sung, Stephen L. Chan, Alfred Sze‐Lok Cheng
Abstract
Background Genomic screening uncovered interferon-gamma (IFNγ) pathway defects in tumours refractory to immune checkpoint blockade (ICB). However, its non-mutational regulation and reversibility for therapeutic development remain less understood. Objective We aimed to identify ICB resistance-associated druggable histone deacetylases (HDACs) and develop a readily translatable combination approach for patients with hepatocellular carcinoma (HCC). Design We correlated the prognostic outcomes of HCC patients from a pembrolizumab trial ( NCT03419481 ) with tumourous cell expressions of all HDAC isoforms by single-cell RNA sequencing. We investigated the therapeutic efficacy and mechanism of action of selective HDAC inhibition in 4 ICB-resistant orthotopic and spontaneous models using immune profiling, single-cell multiomics and chromatin immunoprecipitation-sequencing and verified by genetic modulations and co-culture systems. Results HCC patients showing higher HDAC1 / 2 / 3 expressions exhibited deficient IFNγ signalling and poorer survival on ICB therapy. Transient treatment of a selective class-I HDAC inhibitor CXD101 resensitised HDAC1/2/3 high tumours to ICB therapies, resulting in CD8 + T cell-dependent antitumour and memory T cell responses. Mechanistically, CXD101 synergised with ICB to stimulate STAT1-driven antitumour immunity through enhanced chromatin accessibility and H3K27 hyperacetylation of IFNγ-responsive genes. Intratumoural recruitment of IFNγ + GZMB + cytotoxic lymphocytes further promoted cleavage of CXD101-induced Gasdermin E (GSDME) to trigger pyroptosis in a STAT1-dependent manner. Notably, deletion of GSDME mimicked STAT1 knockout in abolishing the antitumour efficacy and survival benefit of CXD101-ICB combination therapy by thwarting both pyroptotic and IFNγ responses. Conclusion Our immunoepigenetic strategy harnesses IFNγ-mediated network to augment the cancer-immunity cycle, revealing a self-reinforcing STAT1-GSDME pyroptotic circuitry as the mechanistic basis for an ongoing phase-II trial to tackle ICB resistance ( NCT05873244 ).