Fig. 2: LYN kinase in fibroblasts supported primary CLL cell survival in vitro.

a, Illustration of the different in vitro co-culture systems: Primary human CLL samples were isolated from the peripheral blood of CLL patients. LYN proficient and deficient stromal feeder cells were either isolated from MEF of Lyn^wt/wt and Lyn^−/− mice or generated in human BMSC lines via CRISPR/Cas9. Leukemic and stromal cells were co-cultured, and CLL viability (defined as proportion of Annexin V^-/7AAD⁻ cells of all CD45⁺ cells) was measured over time by flow cytometry. Illustration was created with BioRender.com. b Lyn^wt/wt and Lyn^−/− MEF (n = 2 clones per genotype) were used in co-culture with primary human CLL samples (n = 3). Depicted is the CLL viability over time (mean ± SEM; two-sided Mann-Whitney test for Lyn^wt/wt vs. Lyn^−/− at each time point: 24 h–72 h p = 0.002165). c, d LYN^WT and LYN^KO HS-5 single-cell clones (SCC) were used in co-culture with CLL cells. (CLL n = 19; 2 clones per HS-5 genotype). c illustrates CLL viability over time (mean ± SEM; two-sided Mann-Whitney test for LYN^WT vs. LYN^KO at each time point: 72 h p = 0.003056; 96 h p = 0.013878) and (d) highlights individual sample viability after 72 h of co-culture (single representative HS-5 clone per genotype; bars represent mean viability; two-tailed Wilcoxon rank test: in all tests p < 0.0001). e, f LYN^WT and LYN^KO NKtert Cas9 SCCs were used for co-culture assays with CLL cells. (CLL n = 10; LYN^WT 1 clone, LYN^KO 5 clones). e illustrates CLL viability over time (mean ± SEM; two-sided Mann-Whitney test for LYN^WT vs. LYN^KO at each time point: 72 h p = 0.049609) and (f) highlights individual sample viability after 48 h of co-culture (from 8 CLL patients; LYN^WT: 1 clone; LYN^KO: every circle represents mean viability on 5 distinct LYN^KO clones; bars represent mean viability; Wilcoxon rank test: in all tests p = 0.0078). See also Fig. S1. Source data are provided as a Source Data file.