Fig 1: GAS6 activates mTOR signaling involved in the conversion of DTCs to CSCs through MerIn vitro sphere formation assays ((A) PC3 and (B) C4-2B)) and (C) MTT cell viability assays with/without Mer inhibitor (UNC1062). Significance vs. vehicle treatment (Student's t-test). (D) PC3 cells (shControl and shMer) were co-cultured with osteoblasts and 48 h later the CSCs in prostate cancer were measured by flow cytometry. Significance vs. shControl (Student's t-test). (E) Prostate cancer cells, pre-incubated (24 h) with UNC1062 (250 nM), were inoculated intracardially and 24 h later the CSCs in disseminated prostate cancer obtained from the bone marrow of mice inoculated with prostate cancer cells were measured by flow cytometry (n = 5). The % of CSCs population in the marrow was normalized to the vehicle control group that equals 100%, and presened as % change. Significance vs. vehicle treated prostate cancer (Student's t-test). (F) PC3 cells, pre-incubated (1 h) with Rapamycin (10 nM), were co-cultured with osteoblasts and 48 h later the CSCs in prostate cancer were measured by flow cytometry. (G) Prostate cancer cells, pre-incubated (1 h) with Rapamycin (13346, Cayman Chemical, 10 nM), CXCR4 inhibitor (AMD3100, A-5602, Sigma-Aldrich, 10 nM), or Wnt inhibitor (IWR-1-endo, 13659, Cayman Chemical, 10 µM), were inoculated intracardially and 24 h later the CSCs in disseminated prostate cancer were measured by flow cytometry (n = 5). Significance vs. vehicle treated prostate cancer (Student's t-test). *p < 0.05 and #p < 0.01.