Abstract
Primary hepatocytes stimulated with epidermal growth factor (EGF) secrete prostaglandins into the culture medium as soon as 1 h after the addition of the EGF. Transforming growth factor-alpha (TGF alpha), a potent hepatocyte mitogen, shares the same receptor with EGF, and its expression is increased after partial hepatectomy. TGF alpha is also secreted in culture. We have observed that TGF alpha induced hepatocyte DNA synthesis (30 h after addition) and at the same time stimulated the production of prostaglandins E2 and F2 alpha by the cultured hepatocytes. Indomethacin at 20-100 microM inhibited the TGF alpha-induced hepatocyte DNA synthesis, and this effect was specifically due to the inhibition of prostaglandin formation. Indomethacin also inhibited a TGF-alpha-induced increase in hepatocyte c-myc expression, indicating that prostaglandins mediate this increase, as previously shown for EGF. TGF alpha increased the expression of the EGF receptor gene, and this was prevented by the presence of an antibody against TGF alpha in the culture medium. We therefore suggest that TGF alpha induces hepatocyte proliferation either through coupling with its receptor (i.e. the EGF receptor) or by subsequent phosphorylation of lipocortin I. This leads to activation of phospholipase. A2, which seems to regulate the metabolism of arachidonic acid and the formation of prostaglandins. Thus hepatocyte proliferation in vitro appears to be controlled by a self-regulatory autocrine pathway involving activation of phospholipase A2 and secretion of prostaglandins and TGF alpha.
Full text
PDF




Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Alitalo K., Ramsay G., Bishop J. M., Pfeifer S. O., Colby W. W., Levinson A. D. Identification of nuclear proteins encoded by viral and cellular myc oncogenes. Nature. 1983 Nov 17;306(5940):274–277. doi: 10.1038/306274a0. [DOI] [PubMed] [Google Scholar]
- Bothwell W., Verburg M., Wynalda M., Daniels E. G., Fitzpatrick F. A. A radioimmunoassay for the unstable pulmonary metabolites of prostaglandin E1 and E2: an indirect index of their in vivo disposition and pharmacokinetics. J Pharmacol Exp Ther. 1982 Feb;220(2):229–235. [PubMed] [Google Scholar]
- Derynck R., Roberts A. B., Winkler M. E., Chen E. Y., Goeddel D. V. Human transforming growth factor-alpha: precursor structure and expression in E. coli. Cell. 1984 Aug;38(1):287–297. doi: 10.1016/0092-8674(84)90550-6. [DOI] [PubMed] [Google Scholar]
- Derynck R. Transforming growth factor alpha. Cell. 1988 Aug 26;54(5):593–595. doi: 10.1016/s0092-8674(88)80001-1. [DOI] [PubMed] [Google Scholar]
- Etienne P. L., Baffet G., Desvergne B., Boisnard-Rissel M., Glaise D., Guguen-Guillouzo C. Transient expression of c-fos and constant expression of c-myc in freshly isolated and cultured normal adult rat hepatocytes. Oncogene Res. 1988;3(3):255–262. [PubMed] [Google Scholar]
- Evan G. I., Lewis G. K., Ramsay G., Bishop J. M. Isolation of monoclonal antibodies specific for human c-myc proto-oncogene product. Mol Cell Biol. 1985 Dec;5(12):3610–3616. doi: 10.1128/mcb.5.12.3610. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fava R. A., Cohen S. Isolation of a calcium-dependent 35-kilodalton substrate for the epidermal growth factor receptor/kinase from A-431 cells. J Biol Chem. 1984 Feb 25;259(4):2636–2645. [PubMed] [Google Scholar]
- Goueli S. A., Ahmed K. Indomethacin and inhibition of protein kinase reactions. Nature. 1980 Sep 11;287(5778):171–172. doi: 10.1038/287171a0. [DOI] [PubMed] [Google Scholar]
- Handler J. A., Danilowicz R. M., Eling T. E. Mitogenic signaling by epidermal growth factor (EGF), but not platelet-derived growth factor, requires arachidonic acid metabolism in BALB/c 3T3 cells. Modulation of EGF-dependent c-myc expression by prostaglandins. J Biol Chem. 1990 Mar 5;265(7):3669–3673. [PubMed] [Google Scholar]
- Kapp L. N., Brown S. L., Klevecz R. R. Detecting small quantities of DNA on CsCl gradients. Biochim Biophys Acta. 1974 Aug 29;361(2):140–143. doi: 10.1016/0005-2787(74)90341-4. [DOI] [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Little P., Skouteris G. G., Ord M. G., Stocken L. A. Serum from partially hepatectomized rats induces primary hepatocytes to enter S phase: a role for prostaglandins? J Cell Sci. 1988 Dec;91(Pt 4):549–553. doi: 10.1242/jcs.91.4.549. [DOI] [PubMed] [Google Scholar]
- Makino R., Hayashi K., Sugimura T. C-myc transcript is induced in rat liver at a very early stage of regeneration or by cycloheximide treatment. Nature. 1984 Aug 23;310(5979):697–698. doi: 10.1038/310697a0. [DOI] [PubMed] [Google Scholar]
- Massagué J. Epidermal growth factor-like transforming growth factor. II. Interaction with epidermal growth factor receptors in human placenta membranes and A431 cells. J Biol Chem. 1983 Nov 25;258(22):13614–13620. [PubMed] [Google Scholar]
- Mead J. E., Fausto N. Transforming growth factor alpha may be a physiological regulator of liver regeneration by means of an autocrine mechanism. Proc Natl Acad Sci U S A. 1989 Mar;86(5):1558–1562. doi: 10.1073/pnas.86.5.1558. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Michalopoulos G. K. Liver regeneration: molecular mechanisms of growth control. FASEB J. 1990 Feb 1;4(2):176–187. [PubMed] [Google Scholar]
- Muakkassah-Kelly S. F., Jans D. A., Lydon N., Bieri F., Waechter F., Bentley P., Stäubli W. Electroporation of cultured adult rat hepatocytes with the c-myc gene potentiates DNA synthesis in response to epidermal growth factor. Exp Cell Res. 1988 Oct;178(2):296–306. doi: 10.1016/0014-4827(88)90400-4. [DOI] [PubMed] [Google Scholar]
- Nakamura T., Ichihara A. Control of growth and expression of differentiated functions of mature hepatocytes in primary culture. Cell Struct Funct. 1985 Mar;10(1):1–16. doi: 10.1247/csf.10.1. [DOI] [PubMed] [Google Scholar]
- Nakamura T., Yoshimoto K., Nakayama Y., Tomita Y., Ichihara A. Reciprocal modulation of growth and differentiated functions of mature rat hepatocytes in primary culture by cell--cell contact and cell membranes. Proc Natl Acad Sci U S A. 1983 Dec;80(23):7229–7233. doi: 10.1073/pnas.80.23.7229. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pepinsky R. B., Sinclair L. K. Epidermal growth factor-dependent phosphorylation of lipocortin. Nature. 1986 May 1;321(6065):81–84. doi: 10.1038/321081a0. [DOI] [PubMed] [Google Scholar]
- Reynolds F. H., Jr, Todaro G. J., Fryling C., Stephenson J. R. Human transforming growth factors induce tyrosine phosphorylation of EGF receptors. Nature. 1981 Jul 16;292(5820):259–262. doi: 10.1038/292259a0. [DOI] [PubMed] [Google Scholar]
- Rozengurt E., Stroobant P., Waterfield M. D., Deuel T. F., Keehan M. Platelet-derived growth factor elicits cyclic AMP accumulation in Swiss 3T3 cells: role of prostaglandin production. Cell. 1983 Aug;34(1):265–272. doi: 10.1016/0092-8674(83)90157-5. [DOI] [PubMed] [Google Scholar]
- Seglen P. O. Preparation of isolated rat liver cells. Methods Cell Biol. 1976;13:29–83. doi: 10.1016/s0091-679x(08)61797-5. [DOI] [PubMed] [Google Scholar]
- Skouteris G. G., Kaser M. R. Prostaglandins E2 and F2a mediate the increase in c-myc expression induced by EGF in primary rat hepatocyte cultures. Biochem Biophys Res Commun. 1991 Aug 15;178(3):1240–1246. doi: 10.1016/0006-291x(91)91026-9. [DOI] [PubMed] [Google Scholar]
- Skouteris G. G., Michalopoulos G. K. Synthesis and phosphorylation of an extracellular polypeptide reacting with anti-MYC antisera in primary rat hepatocyte cultures. Biochem Biophys Res Commun. 1991 Oct 31;180(2):631–637. doi: 10.1016/s0006-291x(05)81112-x. [DOI] [PubMed] [Google Scholar]
- Skouteris G. G., Ord M. G., Stocken L. A. Regulation of the proliferation of primary rat hepatocytes by eicosanoids. J Cell Physiol. 1988 Jun;135(3):516–520. doi: 10.1002/jcp.1041350321. [DOI] [PubMed] [Google Scholar]
- Taylor D., Uhing R. J., Blackmore P. F., Prpić V., Exton J. H. Insulin and epidermal growth factor do not affect phosphoinositide metabolism in rat liver plasma membranes and hepatocytes. J Biol Chem. 1985 Feb 25;260(4):2011–2014. [PubMed] [Google Scholar]
- Xu Y. H., Ishii S., Clark A. J., Sullivan M., Wilson R. K., Ma D. P., Roe B. A., Merlino G. T., Pastan I. Human epidermal growth factor receptor cDNA is homologous to a variety of RNAs overproduced in A431 carcinoma cells. 1984 Jun 28-Jul 4Nature. 309(5971):806–810. doi: 10.1038/309806a0. [DOI] [PubMed] [Google Scholar]


