MiR-130b activity and NR2F6/SGMS1 inhibition is required for MLL-AF4⁺ leukemia maintenance. (A) Experimental layout of rescue experiment for Mll-AF4⁺ pMIRH-130b leukemic mice (18 000 GFP⁺ cells injected) and Mll-AF4⁺ pMIRH-128a leukemic mice (10 000 GFP⁺ cells injected). (B) Survival curve of Mll-AF4⁺ pMIRH-130b rescue mice (pmiRZip-scramble or pmiRZip-130b, NR2F6 or SGMS1 overexpression). (C) GFP chimerism in various organs of Mll-AF4⁺ pMIRH-130b rescue mice. (D) Lineage output in the GFP⁺ fraction of the BM of Mll-AF4⁺ pMIRH-130b rescue mice. (E) Survival curve of Mll-AF4⁺ pMIRH-128a rescue mice with miRNA inhibition (pmiRZip-scramble, pmiRZip-128a, pmiRZip-130b, or pmiRZip-128a+130b). (F) Survival curve of Mll-AF4⁺ pMIRH-128a rescue mice with NR2F6 or SGMS1 overexpression. A statistical comparison of the survival rate of rescue mice was performed using a χ² test to compare the distribution of sick and non-sick mice (indicated next to the number of sick mice/total mice). (G) GFP chimerism in the BM of Mll-AF4⁺ pMIRH-128a rescue mice. (H) Postmortem photos of representative Mll-AF4⁺ pMIRH-128a rescue mice. (I) Apoptosis/necrosis of fresh GFP⁺ cells retrieved from the BM of Mll-AF4⁺ pMIRH-130b and Mll-AF4⁺ pMIRH-128a rescue mice upon NR2F6 or SGMS1 overexpression. Recipients of SGMS1-overexpressing cells were euthanized because of a stroke-like phenotype. Data were compared using a Mann-Whitney U test: *P < .05; **P < .01; ***P < .001. A Gehan-Breslow-Wilcoxon test was used to compare survival curves. Graphs are presented as mean ± standard error of the mean (1 dot = 1 mouse). PB, peripheral blood.