Cao Wei, Chen Guodong, Wu Lijun, Yu K N, Sun Mingyu, Yang Miaomiao, Jiang Yanyi, Jiang Yuan, Xu Yuan, Peng Shengjie, Han Wei
Anhui Province Key Laboratory of Medical Physics and Technology, Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, P. R. China; University of Science and Technology of China, Hefei, P. R. China.
Anhui Province Key Laboratory of Medical Physics and Technology, Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, P. R. China; Hefei Cancer Hospital, Chinese Academy of Sciences, Hefei, P. R. China.
Int J Radiat Oncol Biol Phys. 2023 Feb 1;115(2):440-452. doi: 10.1016/j.ijrobp.2022.07.1841. Epub 2022 Jul 30.
To understand pyroptosis induced by ionizing radiation and its implications for radiation therapy, we explored the involved factors, possible mechanisms of radiation-induced pyroptosis and consequent antitumor immunity.
The occurrence of pyroptosis was assessed by cell morphology, lactate dehydrogenase release, Annexin V/PI staining and the cleavage of Gasdermin E (GSDME). Cell radiosensitivity was tested with MTT and colony survival assays. Xenograft tumor volume, Ki-67, CD8 lymphocytes, and ELISA were used to evaluate the effect of GSDME on tumor suppression after irradiation.
Irradiation induced pyroptosis in GSDME high-expressing tumor cell lines covering lung, liver, breast, and glioma cancers. Cleavage of GSDME occurred in a dose- and time-dependent manner after irradiation, and pyroptosis could be induced by various kinds of irradiation. The combination of chemotherapy drugs for DNA damage (cisplatin or etoposide) or demethylation (decitabine or azacytidine) and irradiation significantly enhanced the occurrence of pyroptosis. Moreover, we revealed that the Caspase 9/Caspase 3/GSDME pathway was involved in irradiation-induced pyroptosis. Notably, enhanced tumor suppression was observed in Balb/c mice bearing GSDME-overexpressing 4T1 tumors compared with those bearing vector tumors for the promotion of antitumor immunity, which was manifested as distinctly elevated levels of cytotoxic T lymphocytes and release of the related cytokines rather than the direct effect of pyroptosis on tumor cell radiosensitivity.
As an immunogenic cell death caused by radiation, pyroptosis promotes antitumor immunity after irradiation. Our findings may provide new insights to improve the efficacy of tumor radiation therapy.
为了解电离辐射诱导的细胞焦亡及其对放射治疗的影响，我们探究了相关因素、辐射诱导细胞焦亡的可能机制以及随之而来的抗肿瘤免疫反应。
通过细胞形态、乳酸脱氢酶释放、膜联蛋白V/碘化丙啶染色以及Gasdermin E（GSDME）的裂解来评估细胞焦亡的发生情况。用MTT法和集落存活试验检测细胞放射敏感性。采用异种移植瘤体积、Ki-67、CD8淋巴细胞以及酶联免疫吸附测定法来评估GSDME对辐射后肿瘤抑制的影响。
辐射诱导了GSDME高表达的肿瘤细胞系（包括肺癌、肝癌、乳腺癌和胶质瘤细胞系）发生细胞焦亡。照射后GSDME的裂解呈剂量和时间依赖性，并且各种辐射均可诱导细胞焦亡。用于DNA损伤的化疗药物（顺铂或依托泊苷）或去甲基化药物（地西他滨或阿扎胞苷）与辐射联合使用可显著增强细胞焦亡的发生。此外，我们发现半胱天冬酶9/半胱天冬酶3/GSDME途径参与了辐射诱导的细胞焦亡。值得注意的是，与携带载体肿瘤的Balb/c小鼠相比，携带过表达GSDME的4T1肿瘤的小鼠中观察到肿瘤抑制增强，这促进了抗肿瘤免疫，表现为细胞毒性T淋巴细胞水平明显升高以及相关细胞因子的释放，而不是细胞焦亡对肿瘤细胞放射敏感性的直接影响。
作为一种由辐射引起的免疫原性细胞死亡，细胞焦亡可促进辐射后的抗肿瘤免疫。我们的研究结果可能为提高肿瘤放射治疗的疗效提供新的见解。
