The small peptide OGP(10-14) acts through Src kinases and RhoA pathways in Mo-7e cells: morphologic and immunologic evaluation.
BACKGROUND
Osteogenic growth peptide (OGP) is an endogenous tetradecapeptide present in micromolar concentrations in mammalian serum; its carboxy-terminal pentapeptide, OGP(10-14), represents its physiologically active fragment. OGP(10-14) induces proliferation and differentiation in fibroblast and osteoblast cell lines, and it enhances hematopoiesis in vitro and in vivo. The signaling pathways triggered by OGP(10-14) are not yet fully known. In the present report, we evaluated the effect of OGP(10-14) on differentiation of a cancer megakaryoblast cell line and its involvement on RhoA and Src family kinases signaling pathway.


METHODS
Cell proliferation of the Mo-7e line was evaluated using the MTT test. Mo-7e differentiation was evaluated by microscopic observation of cell morphology and by expression of the factor VIII-related antigen. Involvement of RhoA and Src kinases on signaling pathways triggered by OGP(10-14) was analyzed using RhoA and Src family kinase (SFK) inhibitors (C3 and PP2) and an immunoperoxidase technique.


RESULTS
OGP(10-14) induces expression of the factor VIII-related antigen, morphologic changes indicative of megakaryocytic differentiation, and a down-regulation of the Fyn Src kinase. These OGP(10-14) effects were prevented by C3 and enhanced by PP2.


CONCLUSIONS
The anti-proliferative and pro-differentiating activities of OGP(10-14) on thrombopoietin (TPO)-primed Mo-7e cells are mediated by RhoA and Src kinase pathways as demonstrated by the use of C3 and PP2.
Mattii
Letizia
L
Department of Human Morphology and Applied Biology, Section of Histology and General Embryology, University of Pisa, Via Roma 67, Pisa, Italy.
Battolla
Barbara
B
Moscato
Stefania
S
Fazzi
Rita
R
Galimberti
Sara
S
Bernardini
Nunzia
N
Dolfi
Amelio
A
Petrini
Mario
M
D036002:ADP Ribose Transferases / Q000494:pharmacology; D001905:Botulinum Toxins / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D006657:Histones / Q000494:pharmacology*; D006801:Humans; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology*; D051076:Proto-Oncogene Proteins c-fyn / Q000378:metabolism; D011743:Pyrimidines / Q000494:pharmacology; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism*; D014841:von Willebrand Factor / Q000378:metabolism
C412373:AG 1879; D006657:Histones; D036341:Intercellular Signaling Peptides and Proteins; D011743:Pyrimidines; D014841:von Willebrand Factor; C074533:osteogenic growth peptide; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; C494957:FYN protein, human; D051076:Proto-Oncogene Proteins c-fyn; D019061:src-Family Kinases; D001905:Botulinum Toxins; D020742:rhoA GTP-Binding Protein