The role of L-carnitine on a restricted number of myeloid leukemia progenitor cells: generation of atypical cell types.
OBJECTIVE
Since cellular maturation largely depends on lipid metabolism, we examined whether L-carnitine (L-C), a substance involved in these biochemical pathways, is able to promote differentiation of the promyelocytic cell line HL-60.


METHODS
Differentiation was assessed by marker analysis, morphology, immunohistochemistry, proliferation and cellular activity assays.


RESULTS
L-C increases HLA-DR and CD14 surface antigens, while morphologic and marker analysis of the treated cells reveals the presence of monocytes, neutrophiles and few dendritic cells. What is important, however, is the induction of cells that have an atypical to this pathway allure staining positive for the neurofilament 3A10 monoclonal antibody, specific for nerve cells and the anti-p75 (Nerve Growth Factor Receptor) monoclonal antibody. The events described concern active and, at the same time, not proliferative senescent cells.


CONCLUSIONS
L-C exerts its differentiation action on a certain fraction of the leukemic population yielding a non-negligible number of atypical for the myeloid lineage cells. These findings complement earlier and recent reports that describe the generation of cells of a different lineage irrelevant to their parent line of differentiation indicating that the hemopoietic pool appears to be the source of any kind of cell types according to the stimulus provided. Thus, in the context of the plasticity theory it appears that the HL-60 cell line also possess the potential to differentiate towards unexpected pathways.
Vassiliadis
S
S
Department of Biology, Department of Mother-Child, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece. simon@biology.uoc.gr
Evangeliou
A
A
Basta
E
E
Dionyssopoulou
E
E
Dimitriou
H
H
Stiakaki
E
E
Kalmanti
M
M
Athanassakis
I
I
D002331:Carnitine / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D018922:HL-60 Cells; D006684:HLA-DR Antigens / Q000378:metabolism; D006801:Humans; D050356:Lipid Metabolism; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D023461:Myeloid Progenitor Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000473:pathology*
D006684:HLA-DR Antigens; D018950:Lipopolysaccharide Receptors; D002331:Carnitine