Phospholipase D activity is elevated in hepatitis C virus core protein-transformed NIH3T3 mouse fibroblast cells.
Hepatitis C Virus (HCV) is associated with a severe liver disease and increased frequency in the development of hepatocellular carcinoma. Overexpression of HCV core protein is known to transform fibroblast cells. Phospholipase D (PLD) activity is commonly elevated in response to mitogenic signals, and has also been overexpressed and hyperactivated in some human cancer cells. The aim of this study was to understand how PLD was regulated in the HCV core protein-transformed NIH3T3 mouse fibroblast cells. We observed that PLD activity was elevated in the NIH3T3 cells overexpressing HCV core protein over the vector alone-transfected control cells, however, expression levels of PLD protein and protein kinase C (PKC) in the HCV core protein-transformed cells was similar to the control cells. Phorbol 12-myristate 13-acetate (PMA), which is known to activate PKC, stimulated PLD activity significantly more in the core protein-transformed cells, in comparison with that of the control cells. PLD activity assay using PKC isozyme-specific inhibitor and PKC translocation experiment showed that PKC-delta was mainly involved in the PMA- induced PLD activation in the core-transformed cells. Moreover, in cells overexpressing HCV core protein, PMA also stimulated p38 kinase more potently than that of the control cells, and an inhibitor of p38 kinase abolished PMA-induced PLD activation in cells overexpressing HCV core protein. Taken together, these results suggest that PLD might be implicated in core protein-induced transformation.
Kim
Joonmo
J
Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.
Choi
Bok Hee
BH
Jang
Kyung Lib
KL
Min
Do Sik
DS
D000818:Animals; D002461:Cell Line, Transformed; D002472:Cell Transformation, Viral; D005347:Fibroblasts / Q000201:enzymology / Q000821:virology; D016174:Hepacivirus / Q000235:genetics / Q000502:physiology*; D051379:Mice; D041681:NIH 3T3 Cells; D010739:Phospholipase D / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology; D051745:Protein Kinase C-delta; D021381:Protein Transport / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000031:analogs & derivatives* / Q000494:pharmacology; D014162:Transfection; D015854:Up-Regulation; D014758:Viral Core Proteins / Q000235:genetics / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology
D014758:Viral Core Proteins; C069130:nucleocapsid protein, Hepatitis C virus; C016658:phorbolol myristate acetate; C497259:Prkcd protein, mouse; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D048051:p38 Mitogen-Activated Protein Kinases; D010739:Phospholipase D; D013755:Tetradecanoylphorbol Acetate