Interleukin-6 inhibits cell proliferation in a rat model of hepatocellular carcinoma

Diarmuid M. Moran, Nicholas Mayes, Leonidas Koniaris, Paul A. Cahill, Ian H. McKillop

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Background: Interleukin-6 (IL-6) plays a critical role in normal hepatic growth and liver regeneration. The aims of the present study are to determine the expression of components of IL-6 signaling in an in vivo model of hepatocellular carcinoma (HCC) and address the role of IL-6 signaling in the progression of HCC. Methods: An in vivo rat HCC model was established and IL-6 receptor (IL-6R) and downstream signaling pathway expression and activity were determined in HCC and normal liver specimens. Tumorigenic HCC cells from resected HCC samples and normal hepatocytes were then isolated and cultured in the presence and absence of recombinant human IL-6 (rhIL-6). Results: HCC specimens demonstrated decreased IL-6Rα/gp130 expression as compared with the normal liver. In contrast, HCC samples had significantly increased IL-6 messenger RNA expression and signal transducers and activators of transcription (STAT)3 activity. Using in vitro cell cultures, we demonstrated that IL-6 stimulated STAT3 and extracellular regulated kinase (ERK) activity in both HCC cells and isolated hepatocytes. However, while STAT3 activation profiles were similar, IL-6 stimulated ERK activity in a biphasic manner in HCC cells and a monophasic, sustained ERK activation in hepatocytes. In HCC cells, a significant induction of cyclin-dependent kinase (CDK) inhibitors, p21waf1/cip1 and P27Kip1 occurred, an effect that was not observed in normal hepatocytes. Finally, we established that IL-6 acted to inhibit serum-stimulated DNA synthesis and cell mitogenesis in HCC cells in vitro. Conclusions: These data demonstrate altered expression of components of IL-6 signaling in HCC in vivo. IL-6 treatment of HCC cells inhibits serum-stimulated mitogenesis, possibly via differences in activation profiles of intracellular signaling pathways and their effect on CDK inhibitor expression/activity.

Original languageEnglish (US)
Pages (from-to)445-457
Number of pages13
JournalLiver International
Volume25
Issue number2
DOIs
StatePublished - Apr 2005
Externally publishedYes

Fingerprint

Hepatocellular Carcinoma
Interleukin-6
Cell Proliferation
Hepatocytes
Interleukin-6 Receptors
Phosphotransferases
Cyclin-Dependent Kinases
Liver
STAT3 Transcription Factor
Liver Regeneration
Serum
Cell Culture Techniques
Messenger RNA

Keywords

  • gp130
  • Hepatocellular carcinoma
  • IL-6Rα
  • Interleukin-6
  • JAK
  • signal transducers and activators of transcription (STAT)

ASJC Scopus subject areas

  • Hepatology

Cite this

Interleukin-6 inhibits cell proliferation in a rat model of hepatocellular carcinoma. / Moran, Diarmuid M.; Mayes, Nicholas; Koniaris, Leonidas; Cahill, Paul A.; McKillop, Ian H.

In: Liver International, Vol. 25, No. 2, 04.2005, p. 445-457.

Research output: Contribution to journalArticle

Moran, Diarmuid M. ; Mayes, Nicholas ; Koniaris, Leonidas ; Cahill, Paul A. ; McKillop, Ian H. / Interleukin-6 inhibits cell proliferation in a rat model of hepatocellular carcinoma. In: Liver International. 2005 ; Vol. 25, No. 2. pp. 445-457.
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T1 - Interleukin-6 inhibits cell proliferation in a rat model of hepatocellular carcinoma

AU - Moran, Diarmuid M.

AU - Mayes, Nicholas

AU - Koniaris, Leonidas

AU - Cahill, Paul A.

AU - McKillop, Ian H.

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N2 - Background: Interleukin-6 (IL-6) plays a critical role in normal hepatic growth and liver regeneration. The aims of the present study are to determine the expression of components of IL-6 signaling in an in vivo model of hepatocellular carcinoma (HCC) and address the role of IL-6 signaling in the progression of HCC. Methods: An in vivo rat HCC model was established and IL-6 receptor (IL-6R) and downstream signaling pathway expression and activity were determined in HCC and normal liver specimens. Tumorigenic HCC cells from resected HCC samples and normal hepatocytes were then isolated and cultured in the presence and absence of recombinant human IL-6 (rhIL-6). Results: HCC specimens demonstrated decreased IL-6Rα/gp130 expression as compared with the normal liver. In contrast, HCC samples had significantly increased IL-6 messenger RNA expression and signal transducers and activators of transcription (STAT)3 activity. Using in vitro cell cultures, we demonstrated that IL-6 stimulated STAT3 and extracellular regulated kinase (ERK) activity in both HCC cells and isolated hepatocytes. However, while STAT3 activation profiles were similar, IL-6 stimulated ERK activity in a biphasic manner in HCC cells and a monophasic, sustained ERK activation in hepatocytes. In HCC cells, a significant induction of cyclin-dependent kinase (CDK) inhibitors, p21waf1/cip1 and P27Kip1 occurred, an effect that was not observed in normal hepatocytes. Finally, we established that IL-6 acted to inhibit serum-stimulated DNA synthesis and cell mitogenesis in HCC cells in vitro. Conclusions: These data demonstrate altered expression of components of IL-6 signaling in HCC in vivo. IL-6 treatment of HCC cells inhibits serum-stimulated mitogenesis, possibly via differences in activation profiles of intracellular signaling pathways and their effect on CDK inhibitor expression/activity.

AB - Background: Interleukin-6 (IL-6) plays a critical role in normal hepatic growth and liver regeneration. The aims of the present study are to determine the expression of components of IL-6 signaling in an in vivo model of hepatocellular carcinoma (HCC) and address the role of IL-6 signaling in the progression of HCC. Methods: An in vivo rat HCC model was established and IL-6 receptor (IL-6R) and downstream signaling pathway expression and activity were determined in HCC and normal liver specimens. Tumorigenic HCC cells from resected HCC samples and normal hepatocytes were then isolated and cultured in the presence and absence of recombinant human IL-6 (rhIL-6). Results: HCC specimens demonstrated decreased IL-6Rα/gp130 expression as compared with the normal liver. In contrast, HCC samples had significantly increased IL-6 messenger RNA expression and signal transducers and activators of transcription (STAT)3 activity. Using in vitro cell cultures, we demonstrated that IL-6 stimulated STAT3 and extracellular regulated kinase (ERK) activity in both HCC cells and isolated hepatocytes. However, while STAT3 activation profiles were similar, IL-6 stimulated ERK activity in a biphasic manner in HCC cells and a monophasic, sustained ERK activation in hepatocytes. In HCC cells, a significant induction of cyclin-dependent kinase (CDK) inhibitors, p21waf1/cip1 and P27Kip1 occurred, an effect that was not observed in normal hepatocytes. Finally, we established that IL-6 acted to inhibit serum-stimulated DNA synthesis and cell mitogenesis in HCC cells in vitro. Conclusions: These data demonstrate altered expression of components of IL-6 signaling in HCC in vivo. IL-6 treatment of HCC cells inhibits serum-stimulated mitogenesis, possibly via differences in activation profiles of intracellular signaling pathways and their effect on CDK inhibitor expression/activity.

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