Expression of the α2-macroglobulin receptor on human neoplastic fibroblastoid cells

The α2-macroglobulin membrane-associated receptor ( α2MR) has been previously detected on hepatocytes, fibroblast, macrophages, syncytiotrophoblasts and recently on human malignant blood cells of myelomonocytic leukemia. In cells growing in vitro from human germ cell tumors α2MR mRNA was detected by Northern blotting. Endocytosis of α2MR from culture medium was detected in these cells by indirect immunofluorescence. In cell extracts α2MR and its degradation products were detected by immunoblotting. The cells expressing α2MR and internalizing α2MR were identified as fibroblast both by their morphology and expression of vimentin intermediate filaments. The role and function of α2MR receptor in the analyzed neoplastic cells of teratomatous origin is discussed. (author)