PDF file - 325K, Supplemental Table 1: Particle Size Distribution and Zeta Potential; Supplemental Figure 1: Transferrin receptor (CD71) expression on AML patient blasts; Supplemental Figure 2: miR entrapment efficiency; Supplemental Figure 3: Relative expression of miR-29b in AML cell lines, patient blasts and bone marrow samples from healthy donors; Supplemental Figure 4: Expression of pri-miR-29b-1 and pri-miR-29b-2 in AML cell lines and patient blasts following Tf-NP-miR-29b treatment; Supplemental Figure 5: Safety profile of Tf-NPs treatment in immune competent mice.
ARTICLE ABSTRACT
Purpose:miR-29b directly or indirectly targets genes involved in acute myeloid leukemia (AML), namely, DNMTs, CDK6, SP1, KIT, and FLT3. Higher miR-29b pretreatment expression is associated with improved response to decitabine and better outcome in AML. Thus, designing a strategy to increase miR-29b levels in AML blasts may be of therapeutic value. However, free synthetic miRs are easily degraded in bio-fluids and have limited cellular uptake. To overcome these limitations, we developed a novel transferrin-conjugated nanoparticle delivery system for synthetic miR-29b (Tf-NP-miR-29b).Experimental Design: Delivery efficiency was investigated by flow cytometry, confocal microscopy, and quantitative PCR. The expression of miR-29b targets was measured by immunoblotting. The antileukemic activity of Tf-NP-miR-29b was evaluated by measuring cell proliferation and colony formation ability and in a leukemia mouse model.Results: Tf-NP-miR-29b treatment resulted in more than 200-fold increase of mature miR-29b compared with free miR-29b and was approximately twice as efficient as treatment with non-transferrin–conjugated NP-miR-29b. Tf-NP-miR-29b treatment significantly downregulated DNMTs, CDK6, SP1, KIT, and FLT3 and decreased AML cell growth by 30% to 50% and impaired colony formation by approximately 50%. Mice engrafted with AML cells and then treated with Tf-NP-miR-29b had significantly longer survival compared with Tf-NP-scramble (P = 0.015) or free miR-29b (P = 0.003). Furthermore, priming AML cell with Tf-NP-miR-29b before treatment with decitabine resulted in marked decrease in cell viability in vitro and showed improved antileukemic activity compared with decitabine alone (P = 0.001) in vivo.Conclusions: Tf-NP effectively delivered functional miR-29b, resulting in target downregulation and antileukemic activity and warrants further investigation as a novel therapeutic approach in AML. Clin Cancer Res; 19(9); 2355–67. ©2013 AACR.
