Characterization of a growth-inhibiting protein present in rat serum that exerts a differential effect on in vitro growth of nonmalignant rat liver cells when compared with Rous sarcoma virus-transformed rat liver cells.
We have previously reported the transformation by Rous sarcoma virus of a cloned epithelial cell line (BRL) established from Buffalo rat liver by H. Coon. The nontransformed (BRL) and transformed (RSV-BRL) cells grew at comparable rates in culture, whereas only the transformed cells were tumorigenic in vivo. We report here on the existence in rat and mouse sera of a growth inhibitor for the nontransformed BRL cells. The transformed BRL cells (RSV-BRL) were insensitive to this inhibitor. The inhibitory activity was not prominent in sera from other species of animals tested except for rabbit; this serum inhibited the growth of RSV-BRL cells more strongly than that of BRL cells. The growth inhibitor was partially purified from rat serum. It is a protein free of lipid and has a molecular weight of about 220 000. The inhibitor could be separated into three components of pI 4.6, 5.2 (major) and 5.6 by isoelectric electrophoresis.
D000818:Animals; D001358:Avian Sarcoma Viruses; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002472:Cell Transformation, Viral; D002850:Chromatography, Gel; D003470:Culture Media; D006131:Growth Inhibitors / Q000097:blood* / Q000494:pharmacology; D007525:Isoelectric Focusing; D008074:Lipoproteins / Q000097:blood / Q000494:pharmacology; D008099:Liver / Q000166:cytology* / Q000382:microbiology / Q000473:pathology; D008565:Membrane Proteins / Q000097:blood* / Q000494:pharmacology; D051381:Rats; D011915:Rats, Inbred BUF
D003470:Culture Media; D006131:Growth Inhibitors; D008074:Lipoproteins; D008565:Membrane Proteins; C031717:growth inhibitory proteins