Dynamic cell cycle kinetics in vitro and in vivo in myelodysplastic syndromes with special reference to the influence of hematopoietic growth factors

Abstract 

We have investigated the effect of HGF in vivo and in vitro in MDS using a recently developed FCM assay involving the simultaneous measurement of cell surface antigens, DNA content, and BrdUrd or IodUrd incorporation. This allows for the determination of the dynamic cell kinetic parameters: LI, T_s, and T_pot and we observed that in vitro HGF stimulation resulted in a significant decrease in mean T_pot values from 6.6 to 3.5 days. Importantly, we demonstrated that in vivo GM-CSF administration to patients with RAEB resulted in a shortening of T_pot within the 2 first weeks of GM-CSF treatment.

Keywords:  Myelodysplastic syndromes, Cell cycle kinetics, T_s and T_pot, In vitro growth factor stimulation, GM-CSF administration, Heterogeneity

Abbreviations:  7-AAD, 7-amino-actinomycin D, AML, acute myeloid leukemia, BD, Becton Dickinson Immunocytometry Systems, BM, bone marrow, BP, band pass, BrdUrd, bromodeoxyuridine, BSA, bovine serum albumin, CM, complete medium, CT, chemotherapy, DMSO, dimethylsulfoxid, FAB, French–American–British, FCM, flow cytometric, FCS, fetal calf serum, G-CSF, granulocyte colony stimulating factor, GM-CSF, granulocyte/monocyte colony stimulating factor, Hgb, hemoglobin, HGF, hematopoietic growth factors, HSC, hematopoietic stem cells, IL, interleukin, IodUrd, iododeoxyuridine, IP, immunophenotyping, IPSS, International Prognostic Scoring System, LDA, leukocyte differentiation antigens, LI, labeling index, MDS, Myelodysplastic Syndromes, MNC, mononuclear cells, MoAb, monoclonal antibodies, NP, Nonidet P, PB, peripheral blood, PBS, phosphate-buffered saline, PFA, paraformaldehyde, PI, propidium iodide, RA, refractory anemia, RAEB, refractory anemia with excess blasts, RAEB-t, refractory anemia with excess blasts in transformation, RAS, refractory anemia with ring sideroblasts, SCF, stem cell factor, T_c, total cell cycle time, T_pot, potential doubling time, T_s, duration of the S-phase