Antileukemic activity of miR-29b with ROR1-targeted delivery of 2A2-ILP in human ROR1 × TCL1 mouse model. (A) 2A2-ILP labeled with FAM-ODN exhibited selective binding of 2A2-ILP to hROR1-expressed splenocytes ex vivo. (B) The 2A2-miR-29b-ILP downregulated DNMT1 and DNMT3A in hROR1-expressed splenocytes by 48 hours, compared with IgG-miR29-bILP control after ex vivo treatment. (C) Engraftment of leukemic splenocytes from Eμ-ROR1-TCL1 double transgenic mice into C57BL/6 mice produced aggressive leukemia. These mice were randomly assigned into 2A2-miR-29b-ILP, IgG-miR-29b-ILP, 2A2-scramble (SC)-ILP, or vehicle treatment cohorts and treated 3 days a week (Monday/Wednesday/Friday every week intraperitoneally [i.p.]). (D) Decreased B220⁺CD5⁺ leukemic cells (blue region) by ∼50%, but not nonleukemic B220⁺CD5^– normal B-cell population (purple region), in 2A2-miR-29b-ILP–treated mice compared with the 2A2-scramble-ILP and IgG-miR-29b-ILP groups. (E) 2A2-miR-29b-ILP treatment (36 days, n = 9; P = .0019; log-rank test) prolonged mice survival significantly compared with the 2A2-scramble-ILP treatment (21 days; n = 7) and IgG-miR-29b-ILP control (27 days; n = 7).