Chelatable cellular copper modulates differentiation and self-renewal of cord blood-derived hematopoietic progenitor cells.
OBJECTIVE
We have demonstrated epigenetic modulation of CD34(+) cell differentiation by the high-affinity copper (Cu) chelator tetraethylenepentamine (TEPA). TEPA slowed down the rate of CD34(+) cell differentiation and increased their engraftability in SCID mice. TEPA biological activity was attributed to its effect on cellular Cu levels as (a) treatment with TEPA resulted in reduction of cellular Cu, and (b) excess of Cu reversed TEPA's activity and accelerated differentiation. In the present study we further evaluated the role of cellular Cu in TEPA's biological activity.


METHODS
The effects of Cu-chloride, TEPA, TEPA/Cu mixtures at various ratios, and a synthesized, stable, TEPA-Cu complex on short- and long-term cord blood-derived CD34(+) cell cultures as well as on the overall and chelatable cellular Cu were investigated.


RESULTS
Addition of TEPA, TEPA/Cu mixtures at up to equimolar concentrations, and the TEPA-Cu complex to CD34(+) cell cultures resulted in inhibition of differentiation and enhancement of long-term self-renewal. Measurement of the overall cellular Cu by atomic absorption spectrophotometry showed 20 to 40% decrease by TEPA while the TEPA-Cu mixture and the TEPA-Cu complex increased cellular Cu by 10- to 20-fold, as did CuCl(2). However, measurement of the cellular pool of labile Cu showed similar reduction (50% from the control) by all the TEPA forms, while CuCl(2) increased it. Thus, inhibition of differentiation and enhancement of self-renewal of CD34(+) cells was correlated with reduction in the cellular chelatable Cu content.


CONCLUSIONS
The results suggest that decreasing of the chelatable Cu pool, rather than overall Cu, is the mechanism that stands behind TEPA's biological activity.
Peled
Toni
T
Gamida Cell Ltd., Jerusalem, Israel. Tony@gamida-cell.com
Glukhman
Elina
E
Hasson
Nira
N
Adi
Sophie
S
Assor
Harel
H
Yudin
Dima
D
Landor
Chana
C
Mandel
Julie
J
Landau
Efrat
E
Prus
Eugenia
E
Nagler
Arnon
A
Fibach
Eitan
E
D000818:Animals; D018952:Antigens, CD34; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology*; D003300:Copper / Q000378:metabolism* / Q000494:pharmacology; D005029:Ethylenediamines / Q000494:pharmacology*; D005312:Fetal Blood / Q000166:cytology / Q000502:physiology*; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000502:physiology*; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D013995:Time
D018952:Antigens, CD34; D002614:Chelating Agents; D005029:Ethylenediamines; D003300:Copper; C034269:tetraethylenepentamine