Abstract: Objective To investigate the effect of circular RNA sirt1 (circ-sirt1) expression on pyroptosis and angiogenesis in gastric cancer cells. 
Methods Pathological tissue samples were collected from 30 gastric cancer patients from Tangshan People′s Hospital and the First Hospital of Hebei Medical University, and the expression levels of circ-sirt1 and pyroptosis-related proteins were detected. Gastric cancer cell lines adenocarcinoma gastric stomach (AGS), human gastric carcinoma-27 (HGC27), Nagoya University-Gastric Cancer-3 (NUGC3), Seoul National University-1 (SNU1), Seoul National University-601 (SNU601) and normal gastric mucosal epithelial cell line-1 (GES-1) were cultured, and the expression levels of circ-sirt1 and pyroptosis-related proteins were detected. Knockdown or overexpression of circ-sirt1 was performed on HGC27 cells, and the changes of cell proliferation activity, angiogenesis ability and pyroptosis-related protein levels were detected. 
Results Compared with para-cancerous tissue and GES-1 cells, the expression levels of circ-sirt1 and pyroptosis-related proteins were decreased in gastric cancer tissue and gastric cancer cells. After knocking down circ-sirt1, the proliferation activity and angiogenesis ability of HGC27 cells were enhanced, while the level of pyroptosis was decreased. After overexpressing circ-sirt1, the proliferation activity and angiogenesis ability of HGC27 cells were weakened, while the level of pyroptosis was increased. 
Conclusion circ-sirt1 is down-regulated in gastric cancer tissue and gastric cancer cell lines, and overexpression of circ-sirt1 can increase the level of pyroptosis in gastric cancer cells and inhibit tumor angiogenesis. 

Key words: stomach neoplasms, circular RNA sirt1, pyroptosis, angiogenesis