RUNX1 mediates survival in a TAL1-negative, TLX3-transformed human T-ALL cell line, and RUNX3 also contributes to human T-ALL survival. (A) The human T-ALL cell line HPB-ALL was transduced with lentiviruses expressing shRNAs against GFP or RUNX1. Apoptotic cells were quantified by Annexin V/7AAD staining followed by flow cytometry. Data are shown as the mean of 3 independent experiments with error bars representing ± SEM. (B) Gene expression in control or RUNX1 knockdown cells was determined by qRT-PCR. Three independent experiments were performed, and data are shown as means with error bars representing ± SEM. (C) RUNX1 or RUNX3 knockdown in KOPTK1 cells induces cell death. The human T-ALL KOPTK1 cell line was transduced with lentiviruses expressing shRNAs against GFP, RUNX1, or RUNX3. Apoptotic cells were quantified by Annexin V/7AAD staining followed by flow cytometry. (D) RUNX1 and RUNX3 binding to N-Me, MYB +14-kb, and MYB –93-kb enhancer loci was determined by ChIP-qPCR. Data are shown as the mean of 4 independent experiments with error bars representing ± SEM (*P < .05, multiple Student t tests). (E-F) The expression of MYB and MYC in RUNX1- or RUNX3-silenced KOPTK1 cells was determined by qRT-PCR. Data are shown as the mean of 3 or 4 independent experiments with error bars representing ± SEM. *P <.05; **P < .005; ***P < .0005, one-way ANOVA multiple comparisons test.