Fig. 1

A high-content screen to identify FDA approved drugs that increase B7-H3 expression in LM7 osteosarcoma cells. a Schematic of the high-content screen to quantify B7-H3 protein expression in a 384-well format. b Representative immunofluorescence images of B7-H3-negative (LM7-KO) and B7-H3-positive (LM7) cells (left panel; scale bars = 100 µm) and quantification of total B7-H3 signal per cell (right panel). Each dot represents the average result of cells in a well (N = 192 wells). c Total (left panel) and mean (right panel) B7-H3 expression per cell after exposure to 1114 FDA approved drugs. Results were normalized by averages of DMSO-treated wells in corresponding plates. Each dot represents the average result of cells in a well. d Coefficients of variation for negative controls of individual assay plates for total and mean B7-H3 signal per cell. e Venn diagram of drugs that increased total, mean, or both total and mean B7-H3 expression per cell. f The chemical structure of I3A. g The total and mean B7-H3 signal per cell after treatment with increasing doses of I3A. LM7 cells were treated with five threefold dilutions of 15 µM I3A for 48 h. Results are normalized by averages of DMSO-treated wells. Data represents mean ± SD (b). ****p < 0.0001 by unpaired t-test (b). AU, arbitrary units