Fig. 4. Identification of CaMKII inhibitor KN-93 against BAP1-deficient cells and the effect of KN-93 on cell survival of MMe cell lines.

a Screening assay with the Screening Committee of Anticancer Drugs (SCADS) library. The MeT-5A cells (BAP1-KO and parental cells) were treated in the presence or absence of 363 chemical compounds (10 μM each), and the cell survival percentages were calculated after normalization to the mean optical densities in the untreated cells (arbitrarily defined as 100%). The results are shown as differential percentages of cell survival between BAP1-WT and BAP1-KO cells. The red spot indicates >50% reduction of cell viability in BAP1-KO cells compared with BAP1-WT cells. b Western blot analysis for CAMK2D and BAP1 expression in the mesothelial and MMe cell lines using GAPDH as the internal control. c The effect of a CAMKII inhibitor KN-93 on the survival of MMe cell lines. Percentages of cell survival were calculated as described above. d The effect of cisplatin, pemetrexed, and KN-93 (Cells were incubated with the indicated concentrations (20, 15, 10, 7.5, 5, 2.5, 1.25, 0.625, and 0 μM) of each drug for 72 h) on the survival of MeT-5A, HOMC-D4, Y-MESO-12, Y-MESO-14, NCI-H2452, ACC-MESO-4, MeT-5A-BAP1-KO, HOMC-D4-BAP1-KO, and Y-MESO-9 cells. MTT assays were performed according to the manufacturer’s instructions. The absorbance was measured at 595 nm using a spectrophotometer. The cell survival percentages were calculated as described above. Black, red, and blue lines indicate cisplatin, pemetrexed, and KN-93, respectively. Data are expressed as the mean ± SE (n = 3). Asterisks indicate significant differences in the efficacy between cisplatin/pemetrexed and KN-93. *p < 0.05.