Estrogen receptor of primary breast cancers: evidence for intracellular proteolysis.
Iodinated oestradiol-labeled oestrogen receptor (ER) isoforms devoid of amino-terminal ABC domains represent about two-thirds of the whole receptor population detected in cytosol samples from human breast cancers. This high frequency could not be ascribed to the expression of truncated mRNAs, or to the proteolysis of the native ER peptide at the time of homogenization or assay, suggesting an intracellular proteolysis. Free amino-terminal and ligand-binding domains maintained together within oligomeric structure(s); increase of ionic strength separated them. The amino-terminal region was consistently detected in the cell nucleus by specific immunohistochemistry leading to the concept of a potential intranuclear association between ER cleavage products and/or other regulatory proteins.
Maaroufi
Y
Y
Laboratoire J-C Heuson de Cancérologie Mammaire, Service de Médecine, Institut Jules Bordet, Brussels, Belgium.
Lacroix
M
M
Lespagnard
L
L
Journé
F
F
Larsimont
D
D
Leclercq
G
G
D000327:Adsorption; D001665:Binding Sites; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D001943:Breast Neoplasms / Q000737:chemistry*; D002467:Cell Nucleus / Q000378:metabolism; D002853:Chromatography, Liquid; D003600:Cytosol / Q000737:chemistry; D017886:Durapatite; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D009994:Osmolar Concentration; D010446:Peptide Fragments / Q000032:analysis / Q000302:isolation & purification; D011189:Potassium Chloride; D011480:Protease Inhibitors / Q000494:pharmacology; D020033:Protein Isoforms / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000032:analysis; D012334:RNA, Neoplasm / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000032:analysis / Q000378:metabolism; D012997:Solvents; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D011480:Protease Inhibitors; D020033:Protein Isoforms; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011960:Receptors, Estrogen; D011994:Recombinant Proteins; D012997:Solvents; D011189:Potassium Chloride; D017886:Durapatite; D010450:Endopeptidases