Department of Experimental Hematology and Biochemistry, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing 100850, P.R. China.
Int J Oncol. 2021 Oct;59(4). doi: 10.3892/ijo.2021.5259. Epub 2021 Sep 3.
Pyroptosis is mediated by gasdermins and serves a critical role in ionizing radiation (IR)‑induced damage in normal tissues, but its role in cancer radiotherapy and underlying mechanisms remains unclear. Long non‑coding (lnc) RNAs serve important roles in regulating the radiosensitivity of cancer cells. The present study aimed to investigate the mechanistic involvement of lncRNAs in IR‑induced pyroptosis in human colorectal cancer HCT116 cells. LncRNA, microRNA (miR)‑448 and gasdermin E (GSDME) levels were evaluated using reverse transcription‑quantitative polymerase chain reaction. Protein expression and activation of gasdermins were measured using western blotting. The binding association between miR‑448 and GSDME was assessed using the dual‑luciferase reporter assay. Pyroptosis was examined using phase‑contrast microscopy, flow cytometry, Cell Counting Kit‑8 assay and lactate dehydrogenase release assay. IR dose‑dependently induced GSDME‑mediated pyroptosis in HCT116 cells. GSDME was identified as a downstream target of miR‑448. LncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) was upregulated in response to IR and enhanced GSDME expression by negatively regulating miR‑448 expression. Notably, NEAT1 knockdown suppressed IR‑induced pyroptosis, full‑length GSDME expression and GSDME cleavage compared with that in irradiated cells. In addition, NEAT1 knockdown rescued the IR‑induced decrease in cell viability in HCT116 cells. The findings of the present study indicated that lncRNA NEAT1 modulates IR‑induced pyroptosis and viability in HCT116 cells via miR‑448 by regulating the expression, but not activation of GSDME. The present study provides crucial mechanistic insight into the potential role of lncRNA NEAT1 in IR‑induced pyroptosis.
细胞焦亡由 Gasdermin 介导，在正常组织中电离辐射 (IR) 诱导的损伤中发挥关键作用，但在癌症放疗中的作用及其潜在机制尚不清楚。长链非编码 (lnc) RNA 在调节癌细胞的放射敏感性方面发挥着重要作用。本研究旨在探讨 lncRNA 在人结直肠癌细胞 HCT116 中 IR 诱导的细胞焦亡中的作用机制。采用逆转录定量聚合酶链反应检测 lncRNA、微小 RNA (miR)-448 和 Gasdermin E (GSDME) 水平。采用 Western blot 法检测 Gasdermins 的蛋白表达和激活情况。采用双荧光素酶报告基因检测 miR-448 与 GSDME 的结合关系。采用相差显微镜、流式细胞术、CCK-8 检测试剂盒和乳酸脱氢酶释放检测试剂盒检测细胞焦亡情况。IR 剂量依赖性诱导 HCT116 细胞中 GSDME 介导的细胞焦亡。GSDME 被鉴定为 miR-448 的下游靶基因。核斑蛋白组装转录物 1 (NEAT1) 在受到 IR 刺激后上调，并通过负调控 miR-448 的表达增强 GSDME 的表达。值得注意的是，与照射细胞相比，NEAT1 敲低抑制了 IR 诱导的细胞焦亡、全长 GSDME 表达和 GSDME 切割。此外，NEAT1 敲低挽救了 IR 诱导的 HCT116 细胞活力降低。本研究结果表明，lncRNA NEAT1 通过 miR-448 调节 GSDME 的表达，而不是激活，调节 GSDME 的表达，从而调节 IR 诱导的 HCT116 细胞焦亡和活力。本研究为 lncRNA NEAT1 在 IR 诱导的细胞焦亡中的潜在作用提供了重要的机制见解。
