Recognition of activated CSF-1 receptor in breast carcinomas by a tyrosine 723 phosphospecific antibody.
The macrophage colony stimulating factor receptor (CSF-1R), the product of the c-fms proto-oncogene, plays an important role in regulating the normal proliferation and differentiation of macrophages and trophoblasts. However, the abnormal expression of CSF-1R transcripts and protein by human breast carcinomas has been shown to correlate with advanced stage and poor prognosis. Ligand activated CSF-1R dimers transphosphorylate several tyrosines in their cytoplasmic domains which provide recognition sites for various effector proteins in multiple signal transduction pathways. In cells transformed by the c-fms oncogene, one of the major CSF-1R phosphotyrosines, pTyr723 is important for phenotypic expression of anchorage-independent growth and metastasis. In order to investigate the relationship between receptor activation/phosphorylation and cellular phenotypes in vitro and in vivo, we prepared a CSF-1R phosphorylation-state specific antibody raised against a specific phosphopeptide of CSF-1R, which included phosphorylated tyrosine 723. On immunoblots of lysates from cells expressing CSF-1R, this antibody recognizes phosphorylated CSF-IR in CSF-1 stimulated cells but not in unstimulated cells. As an immunohistochemical reagent, this antibody stained 52% of invasive human breast tumors (72% of CSF-1R positive cases) in a sample of 114 cases and 38% of carcinoma in situ. This data represents the first direct evidence of in vivo phosphorylation of CSF-1R in human breast carcinomas.
Flick
M B
MB
Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520-8040, USA.
Sapi
E
E
Perrotta
P L
PL
Maher
M G
MG
Halaban
R
R
Carter
D
D
Kacinski
B M
BM
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000737:chemistry*; D000918:Antibody Specificity; D001943:Breast Neoplasms / Q000175:diagnosis / Q000378:metabolism*; D002278:Carcinoma in Situ / Q000378:metabolism; D002478:Cells, Cultured; D003429:Cross Reactions; D000939:Epitopes; D005347:Fibroblasts / Q000378:metabolism; D016236:Genes, fms / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D010748:Phosphopeptides / Q000276:immunology*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000276:immunology*; D000090063:Proto-Oncogene Mas; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000276:immunology* / Q000378:metabolism; D014407:Tumor Cells, Cultured
D000906:Antibodies; D000939:Epitopes; C000715470:MAS1 protein, human; D010748:Phosphopeptides; D000090063:Proto-Oncogene Mas; D019000:Phosphotyrosine; D016186:Receptor, Macrophage Colony-Stimulating Factor