Fig 2: Characterization of KHDRBS1-LCK-driven PTCL in mice.a Kaplan–Meier survival curve after transplantation with HSPC transduced with empty pMIG vector (n = 5) or pMIG-KHDRBS1-LCK (n = 5). Log-rank p value was obtained from a two-sided Chi-square test. b Representative H&E stains of lymph nodes from mice who were transplanted with HSPC transduced with empty vector (n = 5) or KHDRBS1-LCK (n = 1). Low magnification images are in the top row, scalebars represent 200 µm. High magnification images are in the bottom row, scalebars represent 50 µm. c Representative flow cytometry plots for cell suspensions from the lymph nodes of empty vector mice (representative for n = 5) and the KHDRBS1-LCK mouse (n = 1). d Gating strategy for CD4+CD8+ double positive cells and CD4+CD8- single positive cells on thymic cell suspcensions from mice with empty-vector-transduced cells and GFP+ cells in KHDRBS1-LCK induced PTCL (left). Quantification of intracellular TdT with intracellular flow cytometry. e Western blot for phospho-LCK (Tyr394) and total LCK in spleen lysates from mice transduced with HSPC transduced with empty vector or KHDRBS1-LCK-induced PTCL.

Fig 3: KHDRBS1-LCK drives chronic active TCR signaling.a Quantification (left) and representative immunofluorescence images (right) of LCK and CD3e staining on primary T cells with ectopic expression of LCK (n = 268 cells) or KHDRBS1-LCK (n = 242 cells). Each dot represents a cell. Horizontal line and whiskers represent median and interquartile range respectively. p values were calculated with a two-sided Mann-Whitney test. Scalebars represent 10 µm. b Outgrowth of Ba/F3 cells transduced with empty pMIG vector, pMIG-KHDRBS1-LCK or pMIG-KHDRBS1-LCKK273R after withdrawal of IL-3. n = 3 biological replicates per condition. c Growth inhibition of Ba/F3 cells transformed by KHDRBS1-LCK or Ba/F3 cells transduced with empty pMIG vector after a 24-h treatment with dasatinib. n = 3 replicates per condition. d Western blot for total LCK and phospho-LCK (Tyr394) in Jurkat cells transduced with empty pMIG vector, pMIG-LCK, pMIG-KHDRBS1-LCK or pMIG-KHDRBS1-LCKK273R. e Quantification (top) and representative flow cytometry histograms (bottom) for phospho-ZAP70 in primary T cells treated with control immunoglobulin (Ig) or agonistic anti-CD3e antibody in the absence or presence of dasatinib. n = 3 biological replicates per condition. p values were calculated with Tukey’s post-hoc multiple comparisons test. f Intracellular flow cytometry quantification of phospho-ERK1/2 levels in primary T cells treated with control immunoglobulin (Ig) or agonistic anti-CD3e antibody in the absence or presence of dasatinib. n = 3 biological replicates per condition. p values were calculated with Tukey’s post-hoc multiple comparisons test. All data are represented as mean ± SD unless stated otherwise.