Sialidase gene transfection enhances epidermal growth factor receptor activity in an epidermoid carcinoma cell line, A431.

摘要: Glycosphingolipids expressed in cancer cells have been implicated the modulation of tumor cell growth through their interaction with transmembrane signaling molecules such as factor receptors. For glycosphingolipids to interact receptors, presence sialic acid seems be essential. Stable transfection a gene encoding soluble Mr 42,000 sialidase into human epidermoid carcinoma line (A431) provided an approach by which level terminal lipid-bound on surface could altered. In sialidase-positive clones, ganglioside GM3 was diminished, and little change observed protein sialylation. Sialidase-transfected grew faster than control cells. Sialidase expression did not modify binding epidermal (EGF) its receptor but enhanced EGF (EGFR) tyrosine autophosphorylation compared that parental or transfected vector (pcDNA3) alone. Moreover, phosphorylation EGFR, well other substrates, at low concentrations, suggesting increase kinase sensitivity. These data evidence changes appropriate can dramatically affect EGFR activity. Hence, may represent alter growth.