Elsevier

Stem Cell Research

Volume 14, Issue 1, January 2015, Pages 95-104
Stem Cell Research

Long term maintenance of myeloid leukemic stem cells cultured with unrelated human mesenchymal stromal cells,☆☆

https://doi.org/10.1016/j.scr.2014.11.007Get rights and content
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Highlights

  • Unrelated human MSCs support the maintenance of LSCs in a quiescent state in vitro.

  • LSCs co-cultured with MSCs engrafted NSG mice without losing the efficiency.

  • MSCs provided chemo-protection to primary LSCs.

  • Such in vitro culture systems would provide a simple and inexpensive approach to investigate LSCs.

Abstract

Mesenchymal stromal cells (MSCs) support the growth and differentiation of normal hematopoietic stem cells (HSCs). Here we studied the ability of MSCs to support the growth and survival of leukemic stem cells (LSCs) in vitro. Primary leukemic blasts isolated from the peripheral blood of 8 patients with acute myeloid leukemia (AML) were co-cultured with equal numbers of irradiated MSCs derived from unrelated donor bone marrow, with or without cytokines for up to 6 weeks. Four samples showed CD34+CD38 predominance, and four were predominantly CD34+CD38+. CD34+ CD38 predominant leukemia cells maintained the CD34+ CD38 phenotype and were viable for 6 weeks when co-cultured with MSCs compared to co-cultures with cytokines or medium only, which showed rapid differentiation and loss of the LSC phenotype. In contrast, CD34+ CD38+ predominant leukemic cells maintained the CD34+CD38+ phenotype when co-cultured with MSCs alone, but no culture conditions supported survival beyond 4 weeks. Cell cycle analysis showed that MSCs maintained a higher proportion of CD34+ blasts in G0 than leukemic cells cultured with cytokines. AML blasts maintained in culture with MSCs for up to 6 weeks engrafted NSG mice with the same efficiency as their non-cultured counterparts, and the original karyotype persisted after co-culture. Chemosensitivity and transwell assays suggest that MSCs provide pro-survival benefits to leukemic blasts through cell–cell contact. We conclude that MSCs support long-term maintenance of LSCs in vitro. This simple and inexpensive approach will facilitate basic investigation of LSCs and enable screening of novel therapeutic agents targeting LSCs.

Cited by (0)

Funding: This research was supported by the Intramural Research Programs of the National Heart, Lung, and Blood Institute and the National Human Genome Research Institute, NIH.

☆☆

Author contributions: Study concept and design (S.I., A.J.B., A.L., J.J.M.): In vitro experiment and data collection (S.I., A.L., J.J.M., S.M., P.M., A.D., E.P., K.K., N.H.): Analysis and interpretation of data (S.I., A.J.B., P.L., J.J.M., A.L.): Drafting of the manuscript (S.I., A.L., K.R., P.M., P.L., J.J.M., A.J.B.): Clinical sample and clinical data collection (S.I., K.R., A.J.B.): Obtained funding and study supervision (A.J.B., A.L.).

1

Equally contributed to the manuscript.

2

Current Address: Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19143, USA.