Fig. 1

ROR2 enhances resistance of melanoma cells to chemotherapy drugs. A ROR2 overexpression increased cell survival in melanoma cells upon treatment with chemotherapeutic drugs. A375-empty, A375-ROR2, UACC903 empty, and UACC903-ROR2 were treated with cisplatin, paclitaxel, lomustine, dacarbazine, and camptothecin as indicated in Methods, and a crystal violet cytotoxicity assay was performed. Bar graph shows the mean ± standard deviation (SD) (n = 3) of the percent of cytotoxicity. The percentage of cytotoxicity was calculated as the quotient between the number of cells in treated wells and the number of cells in nontreated wells times 100. B ROR2 silencing enhances cell death induced by chemotherapeutic drugs. The experiment was performed as in A using M2-scramble, M2-shROR2, MeWo-scramble, and MeWo-shROR2 cells. C ROR2 prevents apoptosis by lomustine treatment. A375 empty and A375-ROR2 cells were treated with 75 µM lomustine for 48 h, stained with PI/annexin V, and analyzed by flow cytometry. Representative dot plots are shown. D Bar graphs show the mean ± SD (n = 3) of the percentage of live (Q4) and apoptotic (Q2 + Q3) cells from the experiment in C. E, F ROR2 silencing increased apoptosis by lomustine treatment. The experiment was performed as in C and D using M2-scramble and M2-shROR2 cells treated with 100 µM lomustine for 48 h. Statistical significance was tested by a one-tailed Student’s t-test or ANOVA (MeWo) (n = 3). *p < 0.01, **p < 0.001, ***p < 0.0001, n = 3. n.s. not significant