The anticarcinogenic and tumor growth inhibitory activities of lymphotoxin are associated with altered membrane glycoprotein synthesis.

Membrane glycoprotein synthesis was studied in non-tumorigenic and tumor cells treated with the lymphokine hormone, lymphotoxin, to define the biochemical mechanisms by which lymphotoxin prevents carcinogenesis and inhibits growth of tumor cells. Syrian hamster lymphotoxin increased the synthesis of high molecular weight (50,000-250,000) membrane glycoproteins in non-tumorigenic secondary passage NIH/N Syrian hamster embryo fibroblasts and caused a decrease in the synthesis of high molecular weight glycoproteins in benzo[a]pyrene-induced hamster tumor cells. Increased glycoprotein synthesis varied directly with lymphotoxin concentration and duration of treatment and occurred contemporaneously with lymphotoxin-initiated prevention of carcinogen-induced morphologic transformation. These lymphotoxin-stimulated fluctuations in membrane glycoprotein synthesis are evidence of specific biochemical target cell changes associated with the anticarcinogenic and tumor-inhibitory actions of this immunologic hormone.