Figure 3. SCD1 overexpression confirms a competitive advantage for “SCD1-high” cells in the CNS microenvironment.

(A) SCD1 gene expression levels following SCD1 overexpression in 018z cells. (B) Western blot of SCD1 protein after overexpression in 018z cells. (C)I-II Ratio of relative levels of oleoyl-CoA/stearoyl-CoA and of palmitoleoyl-CoA/palmitoyl-CoA in control (CTL) and SCD1-high 018z cells. p=Student’s t-test. (D) Human leukemia burden in 018z xenograft model. Total amount of leukemic cells in CNS, BM and spleen of NSG mice xenografted with human 018z ALL cell line overexpressing SCD1 (SCD1-high) or control (CTL) GFP⁺ at the time of sacrifice. (E) Human leukemia burden in REH xenograft model. Total amount of leukemic cells in CNS, BM and spleen of NSG mice xenografted with human REH ALL cell lines overexpressing SCD1 (SCD1-high) or control (CTL) GFP⁺ at the time of sacrifice. p=paired Student’s t-test. (F) Competition assay in vivo: FACS plots of cells injected (INPUT) and cells isolated from the CNS of the mice at sacrifice (OUTPUT). Top: GFP⁺ control cells transduced with a GFP-carrying lentiviral backbone and mCherry⁺ control cells transduced with a mCherry carrying lentiviral backbone injected in a ratio of 1:1. Bottom: GFP+ SCD1 overexpressing (SCD1-high) cells and mCherry⁺ control cells transduced with a mCherry carrying lentiviral backbone injected in a ratio of 1:1. (G) Ratio of total number of SCD1-high 018z cells (GFP⁺) to control 018z cells (mCherry⁺) in CNS, BM and spleen of NSG mice transplanted with a mixture of the two cell types in a ratio of 1:1. The backbone vector for SCD1 overexpression was used as control vector. p=paired Student’s t-test.