Fig. 1

The constitutive expression of EPHB6 receptor in human T-ALL promotes in vitro proliferation and in vivo cell expansion. (A) Analysis of public COG TARGET dataset shows a significant enrichment of EphB6 mRNA level as compared with those of Eph receptors family in T-ALL patients (***P < 0.0001 n = 264, by one-way ANOVA) and (B) higher EphB6 expression in T-ALL cases versus CD3 + T-cells from healthy donors from the Human Protein Atlas database (***P < 0.0001 n = 20, by Mann-Whitney test). (C) Flow cytometry analysis of abundance of GFP + alive cell fraction after transduction with EPHB6 or empty (EV) lentivectors as indicated. Transduced FACS-sorted subsets of PF382 and RPMI-8402 cell lines were tracked over time at the indicated time points by flow cytometry. Alive GFP + cells were discriminated for DAPI exclusion. Means ± SD fraction of the initial transduction value are plotted for experiments performed in biological triplicate. ***, p < 0.001 (Student’s t-test).(D-E) Flow cytometry analysis of Ki67 level in PF382 (D) and RPMI-8402 (E) cell lines after transduction with EPHB6 or empty (EV) lentivectors as indicated. Transduced subsets of PF382 and RPMI-8402 cell lines were valued after three days of in vitro growth. (F) t-SNE plots based on the immunophenotyping of M71 (PDX#1) and H3255 (PDX#2), two independent clones of PDX samples by multiparametric flow cytometry. (G) Survival of recipient NSG mice after transplantation with FACS-sorted EPHB6 + cell subsets from M71 (PDX#1) and H3255 (PDX#2) PDX samples. The cell doses injected in each of 4 recipient animals are indicated in parentheses. Two separate experiments are depicted using independent PDX clones as indicated