Stem-cell factor regulates the expression of cyclin A and retinoblastoma gene product in the growth and differentiation pathway of human megakaryocytic cells.
The biological effects of c-kit ligand (stem-cell factor: SCF) on an immortalized human megakaryocytic cell line (CMK) was evaluated using methods including the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, surface marker analysis, DNA cell-cycle analysis and immunoblotting. SCF stimulated the growth of CMK cells. Incubation with SCF resulted in increased expression of IIb/IIIa platelet-related glycoprotein (gpIIb, IIIa), indicating enhanced differentiation of CMK cells. Treatment of CMK cells with SCF resulted in a decrease in the subpopulation in the G1 phase, with a reciprocal increase in those in the S phase and the G2 + M phase. Moreover, SCF significantly increased cellular expression of cyclin A, a regulatory subunit of cyclin-dependent protein kinase (CDK), and the ratio of phosphorylated/dephosphorylated retinoblastoma gene product (RB protein). These results suggest that SCF stimulates the growth and differentiation of megakaryocytic cells possibly through mechanisms related to the activation of cell-cycle-dependent serine/threonine kinase and inactivation of the nuclear tumor-suppressor gene product.
Shimizu
E
E
3rd Department of Internal Medicine, Tokushima University School of Medicine, Japan.
Takahashi
Y
Y
Shinohara
A
A
Yamamoto
Y
Y
Yoshida
S
S
Yamamoto
A
A
Sone
S
S
Takaue
Y
Y
Ogura
T
T
D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D016213:Cyclins / Q000096:biosynthesis / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects*; D016161:Genes, Retinoblastoma; D006801:Humans; D008533:Megakaryocytes / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation; D010980:Platelet Membrane Glycoproteins / Q000032:analysis; D016160:Retinoblastoma Protein / Q000378:metabolism; D019089:Stem Cell Factor / Q000494:pharmacology*
D016213:Cyclins; D010980:Platelet Membrane Glycoproteins; D016160:Retinoblastoma Protein; D019089:Stem Cell Factor