Long non-coding RNA nuclear paraspeckle assembly transcript 1 regulates ionizing radiation-induced pyroptosis via microRNA-448/gasdermin E in colorectal cancer cells

Abstract

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 under- lying 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 pyrop- tosis 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 gasder- mins were measured using western blotting. The binding association between miR-448 and GSDME was assessed using the dual-luciferase reporter assay. Pyroptosis was exam- ined 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.