Fig. 2: Co-targeting CXCR4/E-selectin and FLT3 with GMI-1359 and quizartinib reduces leukemia burden and extends survival in PDX leukemia models.

As well as the combination of GMI-1359 and sorafenib improves mouse normal hematopoiesis with upregulation of hematopoiesis-related cytokines. A NSG mice xenografted with FLT3-ITD mutant PDX AML cells received quizartinib and/or GMI-1359, and mouse survival duration was estimated using the Kaplan–Meier method. The arrow bar indicates the treatment duration. Rx = treatment. B Leukemia cell engraftment in peripheral blood was measured by flow cytometry on days 73 and 85, respectively. C Leukemia cell burdens in the BM and spleen were observed by sacrificing three mice in each group at day 85 and staining the histological sections with anti-hCD45 antibodies. Far-right two figures show an enlarged view and indicate hCD45-positive cells from the BM (C-1) and negative cells from the spleen (C-2). D, E NSG mice engrafted with PDX AML cells received sorafenib and/or GMI-1359 (53 days of treatment), and BM histological sections were stained with anti-mouse CD41 and anti-mouse CD13 antibodies. Semiquantitative analysis was performed by counting megakaryocytes (mCD41+) and myelocytes (mCD13+) cells. The numbers on y-axes indicated the fold changes to cell numbers in the vehicle group which was counted as 1. Error bars are presented as the means ± standard deviation. F MOLM14 cells were cultured with MSC/EC for 24 h in hypoxia condition after being pretreated with GMI-1359 for 1 h. Hematopoiesis-related cytokines were analyzed using the Human Cytokine Antibody Array (ab133997, Abcam, Boston, MA) following the manufacturer’s instructions. The numbers were shown in folds by comparing the levels in vehicle media, which was counted as 1. The color scale from 0 (white) to 12 (red) (units in mean normalized spot density). The asterisks indicate the level of statistical significance. *p < 0.05; **p < 0.01; ***p < 0.001; NS not statistically significant.