RICTOR-mediated melanoma spheroid growth induces an MIC phenotype (A,B) Colo829, A375, and SkMel5 cell lines were cultivated under the same condition as Figure 2 and treated with DMSO or an mTOR inhibitor (OSI-027 1 μM) for 10 days and counted (scale bar represents 1000 μm). Graphs represent the mean ± s.d. of an experiment in triplicate (similar results were obtained in three independent experiments). Significance was calculated using the Student’s t-test: * p < 0.05, ** p < 0.01. (C) The expressions of Myc-tagged RICTOR, RICTOR, phosphorylated STAT3 (Y705), total STAT3, MITF, SOX10, and AXL were assessed by Western blotting in Colo829 cells transfected with an empty vector (Control) or with a vector expressing human RICTOR cDNA (RICTOR). (D) Relative mRNA expressions of the different tumor-initiating cell markers (JARID, Tie1, and BMPR1), as well as RICTOR, were assessed by qPCR and normalized to GAPDH in Colo829 cells transfected with an empty vector (Control) or with a vector expressing human RICTOR cDNA (RICTOR).