Endogenous GM-CSF is involved as an autocrine growth factor for human osteoblastic cells.
Granulocyte-macrophage colony-stimulating factor (GM-CSF) is an important modulator of hematopoietic cells. However, the role of GM-CSF in nonhematopoietic cells remains unclear. We have determined whether GM-CSF is an autocrine mitogenic factor for human osteoblastic (hOB) cells. We found by reverse transcriptase-polymerase chain reaction (RT-PCR) that hOB cells express constitutively both GM-CSF and the alpha and beta chains of the GM-CSF receptor (GMR). Immunocytochemistry showed that serum-starved hOB cells express both GM-CSF and GMR alpha chain. Recombinant human (rh) GM-CSF induces a dose-dependent stimulation of hOB cell proliferation, showing that hOB cells have functional GMRs. A specific neutralizing GM-CSF antibody decreased the basal growth rate and suppressed cell proliferation induced by media conditioned by hOB cells, indicating that GM-CSF released by hOB cells is biologically active. Treatment of hOB cells with GM-CSF antisense (AS) oligonucleotide inhibited the endogenous GM-CSF production as shown by ELISA and immunocytochemistry, whereas a random (R) sequence had no effect. AS oligonucleotides markedly inhibited hOB cell growth reversibly, whereas R oligonucleotides had no effect. AS was more effective than the anti-GM-CSF antibody, and the addition of rhGM-CSF did not rescue the inhibitory effect of AS on cell growth. The findings that human osteoblastic cells produce GM-CSF and express functional GMR constitutively and that suppression of endogenous GM-CSF results in inhibition of cell growth demonstrate that GM-CSF is involved as an autocrine growth factor for human osteoblastic cells.
Modrowski
D
D
INSERM Unité 349, Cell and Molecular Biology of Bone and Cartilage, Lariboisière Hospital, Paris, France.
Lomri
A
A
Marie
P J
PJ
D000906:Antibodies / Q000494:pharmacology; D016375:Antisense Elements (Genetics); D015139:Blotting, Southern; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002460:Cell Line / Q000737:chemistry / Q000166:cytology / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics* / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D009500:Neutralization Tests; D010006:Osteoblasts / Q000737:chemistry / Q000166:cytology* / Q000187:drug effects; D010455:Peptides / Q000235:genetics; D016133:Polymerase Chain Reaction; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics* / Q000276:immunology
D000906:Antibodies; D016375:Antisense Elements (Genetics); D010455:Peptides; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor