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Myostatin propeptide expands primitive CML cells
ABCD
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Figure 2. MSTNpp increases progenitor potential of chronic myeloid leukemia (CML) and normal bone marrow (BM) cells. (A) Bar graph showing total cell numbers of CD34+ chronic phase CML cells from a single patient after 7-day culture with increasing concentrations of MSTNpp. The dotted line indicates the number of seed- ed cells at day 0 (n=3). (B) Bar graph showing total cell numbers after culture of 100 ng/mL of MSTNpp with a polyclonal anti-MSTNpp antibody. The same cells and culturing conditions as in (A) were used (n=3). (C) Bar graph showing absolute cell numbers of Lin–Sca-1+c-Kit+ (LSK) BM cells from ScltTA/BCR-ABL mice after 7-day culture with or without 500 ng/mL of MSTNpp (n=3). (D) Bar graph showing total cell numbers of LSK BM cells from WT B6.SJL mice after 7-day culture with or without 500 ng/mL of MSTNpp (n=3). (E) Representative histograms showing CD34 expression of CD34+CD38low chronic phase CML BM cells after a 7-day culture with indicated cytokines. (F) Colony type and number of chronic phase CD34+ and CD34+ CD38low CML cells, pre-cultured for seven days with or without 500 ng/mL of MSTNpp prior to plating in methylcellulose. A cell equivalent of 500 starting cells was plated. Three individual patient samples were used in triplicates. Replating was performed after two weeks in colony culture for one of the samples. No colonies were seen after the 3rd replating. (G) Colony type and number of CD34+CD38low normal BM cells using the same experimental setup as in (F). Cells from two normal donors were used in triplicates. (H) Bar graph showing total cell numbers of CD34+ CD38low CML cells after 3-day culture with and without 100 ng/mL of MSTNpp. Gray bars: cells cultured in suspension; black bars: cells co-cultured with CML mesenchymal stromal cells (MSC). Two individual patient samples were used in triplicates. The dotted line indicates the number of seeded cells. *P≤0.05, **P≤0.01, ***P≤0.001 and ****P≤0.0001. WT: wild type.
haematologica | 2020; 105(8)
2099