Fig 2: PTGDS regulated the viability, proliferation, cell cycle, apoptosis, and invasion of DLBCL cells.A GO analysis of PTGDS associated genes based on the GEO database (GSE31312). B and C The treatment with rhPTGDS and PGD2 promoted cell proliferation in a dose-dependent manner. D Relative expression of PTGDS protein was confirmed by western blotting in lentivirus transfected cells. E–G PTGDS overexpression promoted cell proliferation, and PTGDS knockdown inhibited cell viability, proliferation, and c-myc expression. H–K In a xenograft DLBCL mouse model, the growth rate, weight, volume, and bioluminescence of tumor were higher in the LV-PTGDS group than sh-PTGDS group (n = 6 per group). L and M PTGDS knockdown induced cell cycle arrest at G0/G1 phase and inhibited the expression of Cyclin D1 and CDK2. N and O PTGDS knockdown increased cell apoptosis and regulated the expression of apoptosis-associated proteins. P and Q PTGDS knockdown suppressed cell invasion and the expression of zeb1 and vimentin. After culture for 24–48 h, the percentage of cells in the lower chamber to input cells represented the level of cell invasion. Data are shown as the mean ± SD. *p < 0.05; **p < 0.01; ***p < 0.001.

Fig 3: PTGDS regulated MYH9 and then Wnt–β-catenin–STAT3 signaling through influencing the ubiquitination of GSK3-β in DLBCL.A and B AT56 inhibited the expression of MYH9 and the activation of Wnt–β-catenin–STAT3 signaling in vitro and in vivo. C Confocal immunofluorescent images indicated the colocalization of MYH9 and GSK3-β protein in LY1 and LY3 cells. Bar = 40 μm. D CoIP assay showed the bindings between MYH9 protein and GSK3-β protein in LY1 and LY3 cells. E and F PTGDS and MYH9 inhibition decreased the ubiquitination of GSK3-β and prolonged its half-life in DLBCL. G The role of PTGDS and MYH9 inhibition on the expression of STAT3 mRNA in LY1 and LY3 cells. H ChIP assay showed the binding of TCF4 and STAT3 promoter in LY1 and LY3 cells. Data are shown as the mean ± SD. *p < 0.05; **p < 0.01; ***p < 0.001.

Fig 4: PTGDS promoted DLBCL tumorigenesis by MYH9-mediated regulation of Wnt–ß-catenin-STAT3 signaling.A Wnt3a impaired the cytotoxicity of AT56 in LY1 and LY3 cells. B and C Wnt3a rescued the cell cycle arrest and cell apoptosis promotion caused by AT56. D The inhibition of the Wnt–ß-catenin-STAT3 pathway by AT56 was reversed with Wnt3a. E WP1066 reversed the proliferation promotion caused by PTGDS overexpression. F WP1066 enhanced the effect of AT56 on cell proliferation in LY1 cells (2.5 µM) and LY3 cells (1 µM). G WP1066 enhanced the effect of AT56 on cell apoptosis in LY1 cells and LY3 cells. H and I Blebbistatin reversed the increased proliferation and the activation of Wnt–ß-catenin–STAT3 signaling caused by PTGDS overexpression without change of PTGDS expression. Data are shown as the mean ± SD. *p < 0.05; **p < 0.01; ***p < 0.001.

Fig 5: AT56 enhanced chemo-sensitivity of DLBCL cells through promoting DNA damage.A The expression level of PTGDS mRNA was reduced by adriamycin (ADR) and bendamustine (BEN). B and C The treatment of AT56 (50 µM) enhanced the cytotoxicity of ADR and BEN in LY1 and LY3 cells. D and E AT56 sensitized DLBCL cells to ADR and BEN in cell apoptosis. F Representative images and quantification of the tail of DLBCL cells treated with AT65 (75 and 125 µM) in the comet assay. Bar = 40 µm. G and H Western blotting and immunofluorescent images indicated that AT56 (75 µM) increased the expression of p-H2AX in DLBCL cells. Bar = 40 µm. Data are shown as the mean ± SD. *p < 0.05; **p < 0.01; ***p < 0.001.