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Lack of gp130 expression in hepatocytes attenuates tumor progression in the DEN model.

Hatting M, Spannbauer M, Peng J, Al Masaoudi M, Sellge G, Nevzorova YA, Gassler N, Liedtke C, Cubero FJ, Trautwein C - Cell Death Dis (2015)

Bottom Line: After acute DEN-induced liver injury we observed a reduction in the inflammatory response in gp130(Δhepa) animals as reflected by decreased levels of IL-6 and oncostatin M.However, gp130(Δhepa) livers revealed aberrant STAT5 activation and decreased levels of transforming growth factor-β (TGFβ), pSMAD2/3 and SMAD2, whereas phosphorylation of STAT3 at Tyr705 and Ser727 was absent.Gp130 deletion resulted in STAT3 inhibition but increased STAT5 activation and diminished TGF-dependent signaling.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine III, University Hospital, RWTH Aachen, Aachen, Germany.

ABSTRACT
Chronic liver inflammation is a crucial event in the development and growth of hepatocellular carcinoma (HCC). Compelling evidence has shown that interleukin-6 (IL-6)/gp130-dependent signaling has a fundamental role in liver carcinogenesis. Thus, in the present study we aimed to investigate the role of gp130 in hepatocytes for the initiation and progression of HCC. Hepatocyte-specific gp130 knockout mice (gp130(Δhepa)) and control animals (gp130(f/f)) were treated with diethylnitrosamine (DEN). The role of gp130 for acute injury (0-144 h post treatment), tumor initiation (24 weeks) and progression (40 weeks) was analyzed. After acute DEN-induced liver injury we observed a reduction in the inflammatory response in gp130(Δhepa) animals as reflected by decreased levels of IL-6 and oncostatin M. The loss of gp130 slightly attenuated the initiation of HCC 24 weeks after DEN treatment. In contrast, 40 weeks after DEN treatment, male and female gp130(Δhepa) mice showed smaller tumors and reduced tumor burden, indicating a role for hepatocyte-specific gp130 expression during HCC progression. Oxidative stress and DNA damage were substantially and similarly increased by DEN in both gp130(f/f) and gp130(Δhepa) animals. However, gp130(Δhepa) livers revealed aberrant STAT5 activation and decreased levels of transforming growth factor-β (TGFβ), pSMAD2/3 and SMAD2, whereas phosphorylation of STAT3 at Tyr705 and Ser727 was absent. Our results indicate that gp130 deletion in hepatocytes reduces progression, but not HCC initiation in the DEN model. Gp130 deletion resulted in STAT3 inhibition but increased STAT5 activation and diminished TGF-dependent signaling. Hence, blocking gp130 in hepatocytes might be an interesting therapeutic target to inhibit the growth of HCC.

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Acute DEN treatment, periportal foci and immune infiltration in hepatocyte-specific gp130 knockout mice. Gp130f/f and gp130Δhepa animals were treated with a single i.p. injection of DEN and killed at the indicated time-points. (a) Representative H&E staining of the liver sections (untreated, 24 and 72 h) (upper panel). Dotted areas in yellow represent necrotic foci. Dotted areas in green represent infiltration. Liver infiltrating PMN (b) and inflammatory monocytes (c) in 24 and 72 h DEN-treated gp130f/f and gp130Δhepa mice were analyzed with FACS, and quantified and represented using FlowJo. Total liver was extracted and MPO (d) was performed. Serum alanine transaminase (ALT) (e) and serum aspartate transaminase (AST) (f) levels were determined in gp130Δhepa and gp130f/f mice after DEN treatment at different time points ranging 0–144 h. All graphs show mean+SEM (n=5, *P<0.05; ***P<0.001).
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fig1: Acute DEN treatment, periportal foci and immune infiltration in hepatocyte-specific gp130 knockout mice. Gp130f/f and gp130Δhepa animals were treated with a single i.p. injection of DEN and killed at the indicated time-points. (a) Representative H&E staining of the liver sections (untreated, 24 and 72 h) (upper panel). Dotted areas in yellow represent necrotic foci. Dotted areas in green represent infiltration. Liver infiltrating PMN (b) and inflammatory monocytes (c) in 24 and 72 h DEN-treated gp130f/f and gp130Δhepa mice were analyzed with FACS, and quantified and represented using FlowJo. Total liver was extracted and MPO (d) was performed. Serum alanine transaminase (ALT) (e) and serum aspartate transaminase (AST) (f) levels were determined in gp130Δhepa and gp130f/f mice after DEN treatment at different time points ranging 0–144 h. All graphs show mean+SEM (n=5, *P<0.05; ***P<0.001).

Mentions: To investigate the role of gp130 for immediate, tumor-initiating events, gp130f/f and gp130Δhepa mice were subjected to high-dose DEN injection (200 mg/kg i.p.) and killed up to 144 h after treatment (Figure 1a–f). Pathological examination of the H&E sections evidenced pericentral foci of small dysplastic hepatocytes and the presence of inflammatory cells observable 24 h after DEN stimulation in both groups (Figure 1a,Supplementary Figure 1). However, periportal necrosis and inflammatory cells were more pronounced in gp130f/f compared with gp130Δhepa livers (Figure 1a,Supplementary Figure 1). Consistently, FACS analysis showed significantly reduced infiltration of polymorphonuclear neutrophil (PMN) and a tendency for a decreased number of inflammatory monocytes in livers of gp130Δhepa compared with gp130f/f animals 72 h after DEN treatment (Figure 1b and c), whereas the numbers of hepatic T, B, and NK cells were unchanged (Supplementary Figure 2a and c). Moreover, 24 h after DEN treatment, myeloperoxidase activity (MPO), a marker for PMN recruitment, was slightly attenuated (P=0.51) in gp130Δhepa compared with gp130f/f animals in liver tissue homogenates (Figure 1d).


Lack of gp130 expression in hepatocytes attenuates tumor progression in the DEN model.

Hatting M, Spannbauer M, Peng J, Al Masaoudi M, Sellge G, Nevzorova YA, Gassler N, Liedtke C, Cubero FJ, Trautwein C - Cell Death Dis (2015)

Acute DEN treatment, periportal foci and immune infiltration in hepatocyte-specific gp130 knockout mice. Gp130f/f and gp130Δhepa animals were treated with a single i.p. injection of DEN and killed at the indicated time-points. (a) Representative H&E staining of the liver sections (untreated, 24 and 72 h) (upper panel). Dotted areas in yellow represent necrotic foci. Dotted areas in green represent infiltration. Liver infiltrating PMN (b) and inflammatory monocytes (c) in 24 and 72 h DEN-treated gp130f/f and gp130Δhepa mice were analyzed with FACS, and quantified and represented using FlowJo. Total liver was extracted and MPO (d) was performed. Serum alanine transaminase (ALT) (e) and serum aspartate transaminase (AST) (f) levels were determined in gp130Δhepa and gp130f/f mice after DEN treatment at different time points ranging 0–144 h. All graphs show mean+SEM (n=5, *P<0.05; ***P<0.001).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4385909&req=5

fig1: Acute DEN treatment, periportal foci and immune infiltration in hepatocyte-specific gp130 knockout mice. Gp130f/f and gp130Δhepa animals were treated with a single i.p. injection of DEN and killed at the indicated time-points. (a) Representative H&E staining of the liver sections (untreated, 24 and 72 h) (upper panel). Dotted areas in yellow represent necrotic foci. Dotted areas in green represent infiltration. Liver infiltrating PMN (b) and inflammatory monocytes (c) in 24 and 72 h DEN-treated gp130f/f and gp130Δhepa mice were analyzed with FACS, and quantified and represented using FlowJo. Total liver was extracted and MPO (d) was performed. Serum alanine transaminase (ALT) (e) and serum aspartate transaminase (AST) (f) levels were determined in gp130Δhepa and gp130f/f mice after DEN treatment at different time points ranging 0–144 h. All graphs show mean+SEM (n=5, *P<0.05; ***P<0.001).
Mentions: To investigate the role of gp130 for immediate, tumor-initiating events, gp130f/f and gp130Δhepa mice were subjected to high-dose DEN injection (200 mg/kg i.p.) and killed up to 144 h after treatment (Figure 1a–f). Pathological examination of the H&E sections evidenced pericentral foci of small dysplastic hepatocytes and the presence of inflammatory cells observable 24 h after DEN stimulation in both groups (Figure 1a,Supplementary Figure 1). However, periportal necrosis and inflammatory cells were more pronounced in gp130f/f compared with gp130Δhepa livers (Figure 1a,Supplementary Figure 1). Consistently, FACS analysis showed significantly reduced infiltration of polymorphonuclear neutrophil (PMN) and a tendency for a decreased number of inflammatory monocytes in livers of gp130Δhepa compared with gp130f/f animals 72 h after DEN treatment (Figure 1b and c), whereas the numbers of hepatic T, B, and NK cells were unchanged (Supplementary Figure 2a and c). Moreover, 24 h after DEN treatment, myeloperoxidase activity (MPO), a marker for PMN recruitment, was slightly attenuated (P=0.51) in gp130Δhepa compared with gp130f/f animals in liver tissue homogenates (Figure 1d).

Bottom Line: After acute DEN-induced liver injury we observed a reduction in the inflammatory response in gp130(Δhepa) animals as reflected by decreased levels of IL-6 and oncostatin M.However, gp130(Δhepa) livers revealed aberrant STAT5 activation and decreased levels of transforming growth factor-β (TGFβ), pSMAD2/3 and SMAD2, whereas phosphorylation of STAT3 at Tyr705 and Ser727 was absent.Gp130 deletion resulted in STAT3 inhibition but increased STAT5 activation and diminished TGF-dependent signaling.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine III, University Hospital, RWTH Aachen, Aachen, Germany.

ABSTRACT
Chronic liver inflammation is a crucial event in the development and growth of hepatocellular carcinoma (HCC). Compelling evidence has shown that interleukin-6 (IL-6)/gp130-dependent signaling has a fundamental role in liver carcinogenesis. Thus, in the present study we aimed to investigate the role of gp130 in hepatocytes for the initiation and progression of HCC. Hepatocyte-specific gp130 knockout mice (gp130(Δhepa)) and control animals (gp130(f/f)) were treated with diethylnitrosamine (DEN). The role of gp130 for acute injury (0-144 h post treatment), tumor initiation (24 weeks) and progression (40 weeks) was analyzed. After acute DEN-induced liver injury we observed a reduction in the inflammatory response in gp130(Δhepa) animals as reflected by decreased levels of IL-6 and oncostatin M. The loss of gp130 slightly attenuated the initiation of HCC 24 weeks after DEN treatment. In contrast, 40 weeks after DEN treatment, male and female gp130(Δhepa) mice showed smaller tumors and reduced tumor burden, indicating a role for hepatocyte-specific gp130 expression during HCC progression. Oxidative stress and DNA damage were substantially and similarly increased by DEN in both gp130(f/f) and gp130(Δhepa) animals. However, gp130(Δhepa) livers revealed aberrant STAT5 activation and decreased levels of transforming growth factor-β (TGFβ), pSMAD2/3 and SMAD2, whereas phosphorylation of STAT3 at Tyr705 and Ser727 was absent. Our results indicate that gp130 deletion in hepatocytes reduces progression, but not HCC initiation in the DEN model. Gp130 deletion resulted in STAT3 inhibition but increased STAT5 activation and diminished TGF-dependent signaling. Hence, blocking gp130 in hepatocytes might be an interesting therapeutic target to inhibit the growth of HCC.

Show MeSH
Related in: MedlinePlus