Fig. 2: PD-L1 facilitates angiogenesis in UM.

a, b Stable silencing of PD-L1 in the UM cell lines MUM2B and MEL290 verified by western blot (a) and IF staining (b). c IGV tracks for PD-L1 expression from RNA-seq analysis of PD-L1-silenced cells and control cells. d Schematic diagram summarizing the angiogenesis assays used to determine the role of PD-L1, including HUVEC migration, HUVEC tube formation, CAM assays, and orthotopic xenografts. e HUVEC migration assay that investigates the effect of conditional medium from PD-L1-silenced cells and control cells on the migration ability of HUVECs. Scale bars, 100 µm. f Statistical analysis of the HUVEC migration assay. n = 3. Data are presented as means ± SD. Two-tailed unpaired Student’s t-test. g HUVEC tube formation assay that investigates the effect of conditional medium from PD-L1-silenced cells and control cells on HUVEC tubule formation. Scale bars, 50 µm. h Statistical analysis of the HUVEC tube formation assay. n = 3. Data are presented as means ± SD. Two-tailed unpaired Student’s t-test. i Representative images and quantitative analysis of blood vessels of CAM treated with conditional medium from PD-L1-silenced cells and control cells. n = 5. Data are presented as means ± SD. Two-tailed unpaired Student’s t-test. j Representative images of UM orthotopic xenografts generated by MUM2B cells expressing control or PD-L1 shRNA. k IF images of PD-L1 and CD31 in UM orthotopic xenografts. Scale bars, 40 µm. l Statistical analysis of CD31 expression in UM orthotopic xenografts. n = 5. Data are presented as means ± SD. Two-tailed unpaired Student’s t-test. m Representative bioluminescent images of UM orthotopic xenografts. n Statistical analysis of the bioluminescent signals in UM orthotopic xenografts. n = 5. Data are presented as means ± SD. Two-tailed unpaired Student’s t-test. o Representative images of H&E staining of UM orthotopic xenografts. p Statistical analysis of the tumor weight. n = 5. Data are presented as means ± SD. Two-tailed unpaired Student’s t-test.