Background: Autologous hematopoietic stem cell transplantation is an effective therapeutic strategy for lymphoma patients. However, some patients have to give up receiving transplantation because of failing to obtain sufficient CD34+ cells yields. Therefore, we ex vivo expanded HSCs of lymphoma patients using UM171 to solve the problem of HSCs deficiency.
Methods: Mobilized peripheral blood-derived CD34+ cells from lymphoma patients were cultured for 10 days with or without UM171. The fold of cell expansion and the immunophenotype of expanded cells were assessed by flow cytometry. RNA-seq experiment was performed to identify the mechanism by which UM171 promoted HSCs expansion.
Results: UM171 treatment increased the proportion of CD34+ (68.97 ± 6.91%), CD34+ CD38- cells (44.10 ± 9.20%) and CD34+CD38-CD45RA-CD90+ LT-HSCs (3.05 ± 2.08%) compared to vehicle treatment (36.08 ± 11.14%, 18.30 ± 9.49% and 0.56 ± 0.45%, respectively). UM171 treatment led to an 85.08-fold increase in LT-HSC numbers relative to initial cells. Importantly, UM171 promoted expansion of LT-HSCs achieved 138.57-fold in patients with poor mobilization. RNA-seq data showed that UM171 upregulated expression of HSC-, mast cell-specific genes and non-canonical Wnt signaling related genes, and inhibited genes expression of erythroid, megakaryocyte and inflammatory mediated chemokine.
Conclusions: Our study shows that UM171 can efficiently promote ex vivo expansion of HSCs from lymphoma patients, especially for poorly mobilizing patients. In terms of mechanism, UM171 upregulate HSC-specific genes expression and suppress erythroid and megakaryocytic differentiation, as well as activate non-classical Wnt signaling.
Keywords: Expansion; Hematopoietic stem cells; Lymphoma; Small molecules; UM171.
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