cGAS activation converges with intracellular acidification to promote STING aggregation and pyroptosis in tumor models
Li Xiao, Yuan-li Ai, Xiang-yu Mi, Han Liang, Xiang Zhi, Liu-zheng Wu, Qi-tao Chen, Tong Gou, Chao Chen, Bo Zhou, Wen-bin Hong, Lu-ming Yao, Jun-jie Chen, Xianming Deng, Fu-nan Li, Qiao Wu, Hang-zi Chen
Li Xiao, Yuan-li Ai, Xiang-yu Mi, Han Liang, Xiang Zhi, Liu-zheng Wu, Qi-tao Chen, Tong Gou, Chao Chen, Bo Zhou, Wen-bin Hong, Lu-ming Yao, Jun-jie Chen, Xianming Deng, Fu-nan Li, Qiao Wu, Hang-zi Chen
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Research Article Cell biology Oncology

cGAS activation converges with intracellular acidification to promote STING aggregation and pyroptosis in tumor models

Abstract

The cyclic GMP-AMP synthase (cGAS)/stimulator of IFN genes (STING) pathway is intimately associated with antitumoral immunity; however, the direct involvement of this pathway in tumor cell demise remains elusive. Here, we identified a compound, dodecyl 6-hydroxy-2-naphthoate (DHN), that induces pyroptosis in melanoma cells by activating noncanonical cGAS/STING signaling. DHN targets mitochondrial protein cyclophilin D (CypD) to induce the release of mitochondrial DNA, leading to cGAS activation and cyclic GMP-AMP (cGAMP) generation. Meanwhile, DHN-caused intracellular acidification induces protein kinase R-like endoplasmic reticulum kinase (PERK) activation, which promotes STING phosphorylation and polymerization in the presence of cGAMP, thereby facilitating the aggregation of STING in the ER, which serves as a platform to recruit Fas-associated via death domain (FADD) and caspase-8, leading to caspase-8 activation and subsequent gasdermin E cleavage, which ultimately results in pyroptosis of tumor cells and tumor regression in mouse models. The occurrence of this noncanonical cGAS/STING pathway–associated pyroptosis is also observed when both cGAS is activated and intracellular pH declines. Collectively, our findings reveal a pathway that links noncanonical cGAS/STING signaling to gasdermin E–mediated pyroptosis, thereby offering valuable insights for tumor therapy.

Authors

Li Xiao, Yuan-li Ai, Xiang-yu Mi, Han Liang, Xiang Zhi, Liu-zheng Wu, Qi-tao Chen, Tong Gou, Chao Chen, Bo Zhou, Wen-bin Hong, Lu-ming Yao, Jun-jie Chen, Xianming Deng, Fu-nan Li, Qiao Wu, Hang-zi Chen

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Figure 8

Phosphorylation of STING at Ser345 and Ser358 by PERK is critical for DHN-induced pyroptosis.

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Phosphorylation of STING at Ser345 and Ser358 by PERK is critical for DH...
Melanoma A375 cells were treated with DHN (15 μM) for 12 hours to detect STING phosphorylation and the puncta of STING in the ER; and for 20 hours to assess pyroptotic features, unless specifically defined. (A) STINGWT and STINGS345A/S358A were transfected into STING-knockdown cells, followed by the detection of STING phosphorylation (top). STINGWT and STINGS345A/S358A was incubated with PERK in vitro (bottom). (B–D) STINGWT and STINGS345A/S358A were transfected into STING-knockdown cells, followed by detection of STING polymerization (B); STING puncta (C), scale bar: 20 μm; and pyroptosis, scale bar: 100 μm (D). Tubulin was used to determine the amount of loading protein. Data are presented as mean ± SEM of 3 independent experiments. Statistical analyses were determined by 2-way ANOVA with Tukey’s multiple-comparison test (C and D). P values are indicated. All Western blots were repeated at least twice, and 1 of them is shown.