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Fig. 6 | Journal of Hematology & Oncology

Fig. 6

From: Treatment-induced arteriolar revascularization and miR-126 enhancement in bone marrow niche protect leukemic stem cells in AML

Fig. 6

Preventing treatment-induced CD31+Sca-1high re-vascularization enhances LSC sensitivity to TKI. a Schematic design of the experiments. BM MNCs from diseased MllPTD/wt/Flt3ITD/ITD AML mice (CD45.1/CD45.2) were transplanted into normal wt recipient mice (CD45.1, 6 Gy) to generate a cohort of mice with a similar disease onset time. At day 14 post transplantation, the leukemic mice were treated with AC220 (20 mg/kg/day, oral gavage)+ mrTNFα (1 µg/day, ip) or AC220+ vehicle for 3 weeks. After completion of treatment, a cohort of treated mice (n = 12 mice per group) were monitored for survival and another cohort of mice (n = 7 mice per group) were euthanized and assessed for BM vascular changes and LSC burden by 2nd transplantation. b and c Long bones (femurs and tibias) from the above leukemic mice treated with AC220+ mrTNFα or AC220+ vehicle for 3 weeks (n = 3 mice per group) were evaluated for: BM EC Sca-1high and Sca-1low subfractions (b left, representative plots; right, aggregate results) by flow cytometry analysis, and CD31+Sca-1high EC-lined vessels (i.e., arterioles) by CD31 (FITC) and Sca-1 (PE) IF staining (c left) and quantification (c, right). For c: Yellow arrows indicate CD31+Sca-1high EC-lined vessels; white arrows indicate CD31+Sca-1low EC-lined vessels; scale bars represent a size of 50 µm. d Representative plots (left) and aggregate results of frequency and number of LSCs (i.e., CD45.1/CD45.2 LSKs, middle), and ratio of LSCs/HSCs (i.e., CD45.1/CD45.2 AML LSKs: CD45.1 normal LSKs, right) in the BM from AC220+ mrTNFα-treated and AC220+ vehicle-treated leukemic mice. e Survival of treated primary AML mice (left) and 2nd recipient mice (right) receiving BM cells from AC220+ mrTNFα-treated or AC220+ vehicle-treated AML donors. f Schematic design of the experiments. BM MNCs from diseased MllPTD/wt/Flt3ITD/ITD mice (CD45.1/CD45.2) were transplanted into wt and EC miR-126 KO (miR-126ECΔ/Δ) recipient mice (CD45.2, 6 Gy) and evaluated for response to AC220 (20 mg/kg/day, oral gavage) given for 3 weeks. g Circulating leukemia burden (left) and frequency of BM LSCs (CD45.1/CD45.2 LSKs, middle) by flow cytometry analysis and miR-126 levels in LSCs by Q-RT-PCR (right) from leukemic miR-126 wt and miR-126ECΔ/Δ mice treated with AC220 for 3 weeks. h Survival of AC220-treated leukemic miR-126 wt and miR-126ECΔ/Δ primary mice (left) and 2nd recipients (right, n = 10 mice per group) of BM cells from the AC220-treated leukemic miR-126 wt and miR-126ECΔ/Δ mice. Results represent mean ± SEM. Significance values: *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001

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