Very Low O2 Concentration (0.1%) Favors G0 Return of Dividing CD34+ Cells

Abstract

STEM CELLS 2006;24: 65-73

Severe Hypoxia Defines Heterogeneity and Selects Highly Immature Progenitors Within Clonal Erythroleukemia Cells

“…3A, 3B) to CRA CFC (data not shown). Thus, hypoxia-resistant STR-type LSC seem to be a more homogeneous, mostly cycling cell subset, whereas STR-HSC are less homogeneous and relatively more quiescent [2,5,13]. This conclusion that stem cell hierarchy within the MEL cell population is different from normal is in keeping with current views on the issue [20].…”

“…This study was based on the adaptation to leukemia cells [11,12] of the CRA assay developed in our laboratory [2] and successfully applied [3,5,7,13] for the quantification in vitro of the stem cell potential of normal hematopoietic cell populations. The CRA assay, in combination with incubation under severe hypoxia as a selection procedure, showed that the MEL cell population includes highly hypoxia-sensitive CFC as well as their hypoxia-resistant, CRC-type progenitors.…”

Searching for the Key to Expand Hematopoietic Stem Cells

“…Similar studies have been performed with cord blood cells (Hermitte et al, 2006). The authors reported preferential survival of primitive HSC among cord blood CD34 + cells in cultures under 0.1% O 2.…”

The Soluble Form of LR11 Protein Is a Regulator of Hypoxia-induced, Urokinase-type Plasminogen Activator Receptor (uPAR)-mediated Adhesion of Immature Hematological Cells

“…Several studies have suggested that long term HSCs reside mainly in the endosteal sites of the BM, in which the pO 2 is very low (3,6). Cell biological studies using HS(P)Cs indicated that their functions as well as their quiescence state are maintained most effectively under hypoxic conditions (10,(47)(48)(49)(50)(51)(52). Hypoxia stabilizes the HIF-1␣ protein, a master regulator of oxygen homeostasis, and activates HIF-1␣-mediated signals in HSCs (48,53,54).…”