title: Low density lipoprotein receptor-related protein (LRP) expression varies among Hep G2 cell lines.
abstract: The multiligand receptor, low density lipoprotein receptor-related protein (LRP), is implicated in processes such as atherosclerosis and fibrinolysis through its mediation of the catabolism of lipoproteins, proteases, and protease inhibitor complexes. The hepatoma cell line Hep G2 expresses LRP and has been used widely to investigate the catabolism of LRP ligands including tissue-type plasminogen activator (tPA). However, the mechanism and degree by which tPA interacts with Hep G2 has been reported with some inconsistencies which may reflect variation in their level of LRP expression. To address this possibility we characterized, antigenically and functionally, LRP expression in high and low passage Hep G2 cells both from the parental line (ATCC sourced) and a cloned subline, a16. The LRP contribution to 125I-tPA binding varied from 65% for high passage a16 cells, to 20% for low passage parent cells as quantified by inhibition in the presence of 39-kD receptor associated protein (RAP) which prevents binding of all known LRP ligands. The same trend in LRP expression among Hep G2 sublines was further evident in their ability to degrade 125I-tPA and survive Pseudomonas exotoxin A challenge. These results imply wide variability in basal LRP expression among Hep G2 lines dependent on cell lineage and long-term culture conditions.
authors.affiliation: Centre for Thrombosis and Vascular Research, University of New South Wales, Sydney, Australia. pggrimsley@one.net.au
authors.forename: P G
authors.initials: PG
authors.lastname: Grimsley
authors.forename: K A
authors.initials: KA
authors.lastname: Quinn
authors.forename: C N
authors.initials: CN
authors.lastname: Chesterman
authors.forename: D A
authors.initials: DA
authors.lastname: Owensby
mesh_terms: D036002:ADP Ribose Transferases; D000911:Antibodies, Monoclonal; D001427:Bacterial Toxins; D001481:Basal Metabolism; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D002352:Carrier Proteins; D005098:Exotoxins; D006023:Glycoproteins; D006801:Humans; D016130:Immunophenotyping; D007457:Iodine Radioisotopes; D026563:LDL-Receptor Related Protein-Associated Protein; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D011869:Radioligand Assay; D011971:Receptors, Immunologic / Q000096:biosynthesis* / Q000276:immunology; D011973:Receptors, LDL; D011994:Recombinant Proteins; D010959:Tissue Plasminogen Activator / Q000378:metabolism; D014407:Tumor Cells, Cultured; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A
chemical_list: D036002:ADP Ribose Transferases; D000911:Antibodies, Monoclonal; D001427:Bacterial Toxins; D002352:Carrier Proteins; D005098:Exotoxins; D006023:Glycoproteins; D007457:Iodine Radioisotopes; D026563:LDL-Receptor Related Protein-Associated Protein; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D011971:Receptors, Immunologic; D011973:Receptors, LDL; D011994:Recombinant Proteins; D010959:Tissue Plasminogen Activator; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A