Recombinant hirudin suppresses angiogenesis of diffuse large B‐cell lymphoma through regulation of the PAR‐1‐VEGF

Abstract Hirudin is one of the specific inhibitors of thrombin, which has been confirmed to have strong bioactivities, including inhibiting tumors. However, the function and mechanism of hirudin and protease‐activated receptor 1 (PAR‐1) in diffuse large B‐cell lymphoma (DLBCL) have not been clear. Detecting the expression PAR‐1 in DLBCL tissues and cells by RT‐qPCR and IHC. Transfected sh‐NC, sh‐PAR‐1, or pcDNA3.1‐PAR‐1 in DLBCL cells or processed DLBCL cells through added thrombin, Vorapaxar, Recombinant hirudin (RH), or Na 2 S 2 O 4 and co‐culture with EA.hy926. And built DLBCL mice observed tumor growth. Detecting the expression of related genes by RT‐qPCR, Western blot, IHC, and immunofluorescence, measured the cellular hypoxia with Hypoxyprobe‐1 Kit, and estimated the cell inflammatory factors, proliferation, migration, invasion, and apoptosis by ELISA, CCK‐8, flow cytometry, wound‐healing and Transwell. Co‐immunoprecipitation and pull‐down measurement were used to verify the relationship. PAR‐1 was highly expressed in DLBCL tissues and cells, especially in SUDHL2. Na 2 S 2 O 4 induced SUDHL2 hypoxia, and PAR‐1 did not influence thrombin‐activated hypoxia. PAR‐1 could promote SUDHL2 proliferation, migration, and invasion, and it was unrelated to cellular hypoxia. PAR‐1 promoted proliferation, migration, and angiogenesis of EA.hy926 or SUDHL2 through up‐regulation vascular endothelial growth factor (VEGF). RH inhibited tumor growth, cell proliferation, and migration, promoted apoptosis of DLBCL, and inhibited angiogenesis by down‐regulating PAR‐1‐VEGF. RH inhibits proliferation, migration, and angiogenesis of DLBCL cells by down‐regulating PAR‐1‐VEGF.