Protein kinase C inhibitor, H-7 suppresses the growth activity of hepatoma-derived growth factor.
OBJECTIVE
A well-differentiated hepatocellular carcinoma-derived cell line, HuH-7 proliferates autonomously in serum-free medium. Human hepatoma-derived growth factor, which was purified from the conditioned medium of HuH-7 cells, stimulates the growth of HuH-7 cells by an autocrine fashion, and fibroblasts and endothelial cells by a paracrine fashion. We investigated the role of protein kinase C in the proliferation of HuH-7 cells and the growth activity of hepatoma-derived growth factor.


METHODS
The effects of a selective protein kinase C inhibitor, H-7 on the proliferation of HuH-7 and 3T3 fibroblasts stimulated by hepatoma-derived growth factor were examined by DNA synthesis and cell growth assay.


RESULTS
H-7 suppressed the growth of HuH-7 cells. The ID50 of H-7 on the growth of HuH-7 cells was about 25 microM, and the growth of HuH-7 cells was almost completely inhibited by not less than 50 microM of H-7. H-7 inhibited the growth activity of hepatoma-derived growth factor for Swiss 3T3 fibroblasts. The ID50 of H-7 on the activity of hepatoma-derived growth factor for 3T3 fibroblasts was about 25 microM, too. HA1004, used as a negative control of H-7, failed to inhibit the growth of HuH-7 cells and the activity of hepatoma-derived growth factor. The growth of HuH-7 cells was stimulated significantly by about 40% by a protein kinase C activator, SC-9. H-7 did not suppress hepatoma-derived growth factor production in HuH-7 cells.


CONCLUSIONS
These findings suggest that protein kinase C plays an important role in the growth of HuH-7 hepatoma cells and may be participated as a pathway in signal transduction of hepatoma-derived growth factor.
Kambe
H
H
Department of Molecular Medicine, Osaka University Medical School, Yamada-oka 2-2, Suita City, Osaka 565-0871, Japan.
Kishima
Y
Y
Kuroda
T
T
Enomoto
H
H
Ogawa
H
H
Nakmaura
H
H
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000494:pharmacology*; D016475:3T3 Cells; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006133:Growth Substances / Q000502:physiology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
D004791:Enzyme Inhibitors; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; C051610:hepatoma-derived growth factor; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011493:Protein Kinase C