Release of an Mr 140,000 glycoprotein in the culture media of certain human sarcoma and melanoma cell lines.

A 140 K glycoprotein was detected in the culture media of human sarcoma and melanoma cell lines by labeling with several radioactive amino acid and sugar precursors, followed by sodium dodecylsulfate-polyacrylamide gel electrophoresis and fluorography. In contrast to this, in the culture media of metabolically labeled embryonic and skin fibroblasts this glycoprotein was not found. Likewise, a protein with an identical molecular weight of 140 K was also found in culture media after cell surface labeling of the neoplastic cells but not in the culture media from control cells. The [35S]methionine-labeled 140 K was not split by collagenase and did not appear to be a fragment of fibronectin. We discuss the possibility that secretion of the 140 K glycoprotein is a transformation-related phenomenon.