Expression of glial fibrillary acidic protein, actin, fibronectin and factor VIII antigen in human astrocytomas.
Frozen sections and cell cultures of 50 human astrocytomas, fetal and adult human brain were examined for immunofluorescence reactivity with antisera to glial fibrillary acidic protein (GFAP), actin, fibronectin and factor VIII antigen. In frozen tissue sections GFAP expression was restricted to normal and neoplastic astrocytes while fibronectin and factor VIII antigen were localized to blood vessels. In primary cell culture, 80-100% neoplastic astrocytes expressed GFAP but not fibronectin or factor VIII antigen while actin was present as diffuse cytoplasmic staining of the cell body and cell processes. By the 5th-6th passage in vitro, GFAP immunoreactivity was lost while fibronectin and actin cables were prominently expressed. Factor VIII antigen remained negative throughout serial subculture. In double fluorochrome experiments, GFAP positive cells did not express fibronectin or actin cables, while GFAP negative cells expressed fibronectin and had prominent actin cables. Our results suggest a change in population of astrocytoma cells with increasing passage in vitro, reflecting either an overgrowth of tumour glioblasts or dedifferentiation of tumour astrocytes.
D000199:Actins / Q000032:analysis*; D000941:Antigens / Q000032:analysis*; D001254:Astrocytoma / Q000032:analysis* / Q000473:pathology; D001921:Brain; D001923:Brain Chemistry; D001932:Brain Neoplasms / Q000032:analysis* / Q000473:pathology; D002460:Cell Line; D002478:Cells, Cultured; D005169:Factor VIII / Q000032:analysis / Q000276:immunology*; D005333:Fetus / Q000032:analysis; D005353:Fibronectins / Q000032:analysis*; D005455:Fluorescent Antibody Technique; D005629:Frozen Sections; D005904:Glial Fibrillary Acidic Protein; D005909:Glioblastoma / Q000032:analysis* / Q000473:pathology; D006801:Humans; D007381:Intermediate Filament Proteins / Q000032:analysis*; D014841:von Willebrand Factor
D000199:Actins; D000941:Antigens; D005353:Fibronectins; D005904:Glial Fibrillary Acidic Protein; D007381:Intermediate Filament Proteins; D014841:von Willebrand Factor; D005169:Factor VIII