Hepatoma cells from mice deficient in glycine N-methyltransferase have increased RAS signaling and activation of liver kinase B1

Nuria Martínez-López, Juan L. García-Rodrgíuez, Marta Varela-Rey, Virginia Gutiérrez, David Fernández-Ramos, Naiara Beraza, Ana M. Aransay, Karin Schlangen, Juan Jose Lozano, Patricia Aspichueta, Zigmund Luka, Conrad Wagner, Matthias Evert, Diego F. Calvisi, Shelly C. Lu, José M. Mato, María L. Martínez-Chantar

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

BACKGROUND & AIMS: Patients with cirrhosis are at high risk for developing hepatocellular carcinoma (HCC), and their liver tissues have abnormal levels of S-adenosylmethionine (SAMe). Glycine N-methyltransferase (GNMT) catabolizes SAMe, but its expression is down-regulated in HCC cells. Mice that lack GNMT develop fibrosis and hepatomas and have alterations in signaling pathways involved in carcinogenesis. We investigated the role of GNMT in human HCC cell lines and in liver carcinogenesis in mice. METHODS: We studied hepatoma cells from GNMT knockout mice and analyzed the roles of liver kinase B1 (LKB1, STK11) signaling via 5′-adenosine monophosphateactivated protein kinase (AMPK) and Ras in regulating proliferation and transformation. RESULTS: Hepatoma cells from GNMT mice had defects in LKB1 signaling to AMPK, making them resistant to induction of apoptosis by adenosine 3′,5′-cyclic monophosphate activation of protein kinase A and calcium/calmodulin-dependent protein kinase kinase 2. Ras-mediated hyperactivation of LKB1 promoted proliferation of GNMT-deficient hepatoma cells and required mitogen-activated protein kinase 2 (ERK) and ribosomal protein S6 kinase polypeptide 2 (p90RSK). Ras activation of LKB1 required expression of RAS guanyl releasing protein 3 (RASGRP3). Reduced levels of GNMT and phosphorylation of AMPKα at Thr172 and increased levels of Ras, LKB1, and RASGRP3 in HCC samples from patients were associated with shorter survival times. CONCLUSIONS: Reduced expression of GNMT in mouse hepatoma cells and human HCC cells appears to increase activity of LKB1 and RAS; activation of RAS signaling to LKB1 and RASGRP3, via ERK and p90RSK, might be involved in liver carcinogenesis and be used as a prognostic marker. Reagents that disrupt this pathway might be developed to treat patients with HCC.

Original languageEnglish (US)
JournalGastroenterology
Volume143
Issue number3
DOIs
StatePublished - Sep 2012
Externally publishedYes

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Glycine N-Methyltransferase
Hepatocellular Carcinoma
Phosphotransferases
Liver
Adenosine
Calcium-Calmodulin-Dependent Protein Kinase Kinase
Protein Kinases
S-Adenosylmethionine
Carcinogenesis
Fibrosis
Proteins
Mitogen-Activated Protein Kinase 1
Cyclic AMP-Dependent Protein Kinases
Knockout Mice

Keywords

  • AMP
  • CaMKK2
  • Liver Cancer
  • Mouse Model

ASJC Scopus subject areas

  • Gastroenterology

Cite this

Martínez-López, N., García-Rodrgíuez, J. L., Varela-Rey, M., Gutiérrez, V., Fernández-Ramos, D., Beraza, N., ... Martínez-Chantar, M. L. (2012). Hepatoma cells from mice deficient in glycine N-methyltransferase have increased RAS signaling and activation of liver kinase B1. Gastroenterology, 143(3). https://doi.org/10.1053/j.gastro.2012.05.050

Hepatoma cells from mice deficient in glycine N-methyltransferase have increased RAS signaling and activation of liver kinase B1. / Martínez-López, Nuria; García-Rodrgíuez, Juan L.; Varela-Rey, Marta; Gutiérrez, Virginia; Fernández-Ramos, David; Beraza, Naiara; Aransay, Ana M.; Schlangen, Karin; Lozano, Juan Jose; Aspichueta, Patricia; Luka, Zigmund; Wagner, Conrad; Evert, Matthias; Calvisi, Diego F.; Lu, Shelly C.; Mato, José M.; Martínez-Chantar, María L.

In: Gastroenterology, Vol. 143, No. 3, 09.2012.

Research output: Contribution to journalArticle

Martínez-López, N, García-Rodrgíuez, JL, Varela-Rey, M, Gutiérrez, V, Fernández-Ramos, D, Beraza, N, Aransay, AM, Schlangen, K, Lozano, JJ, Aspichueta, P, Luka, Z, Wagner, C, Evert, M, Calvisi, DF, Lu, SC, Mato, JM & Martínez-Chantar, ML 2012, 'Hepatoma cells from mice deficient in glycine N-methyltransferase have increased RAS signaling and activation of liver kinase B1', Gastroenterology, vol. 143, no. 3. https://doi.org/10.1053/j.gastro.2012.05.050
Martínez-López N, García-Rodrgíuez JL, Varela-Rey M, Gutiérrez V, Fernández-Ramos D, Beraza N et al. Hepatoma cells from mice deficient in glycine N-methyltransferase have increased RAS signaling and activation of liver kinase B1. Gastroenterology. 2012 Sep;143(3). https://doi.org/10.1053/j.gastro.2012.05.050
Martínez-López, Nuria ; García-Rodrgíuez, Juan L. ; Varela-Rey, Marta ; Gutiérrez, Virginia ; Fernández-Ramos, David ; Beraza, Naiara ; Aransay, Ana M. ; Schlangen, Karin ; Lozano, Juan Jose ; Aspichueta, Patricia ; Luka, Zigmund ; Wagner, Conrad ; Evert, Matthias ; Calvisi, Diego F. ; Lu, Shelly C. ; Mato, José M. ; Martínez-Chantar, María L. / Hepatoma cells from mice deficient in glycine N-methyltransferase have increased RAS signaling and activation of liver kinase B1. In: Gastroenterology. 2012 ; Vol. 143, No. 3.
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abstract = "BACKGROUND & AIMS: Patients with cirrhosis are at high risk for developing hepatocellular carcinoma (HCC), and their liver tissues have abnormal levels of S-adenosylmethionine (SAMe). Glycine N-methyltransferase (GNMT) catabolizes SAMe, but its expression is down-regulated in HCC cells. Mice that lack GNMT develop fibrosis and hepatomas and have alterations in signaling pathways involved in carcinogenesis. We investigated the role of GNMT in human HCC cell lines and in liver carcinogenesis in mice. METHODS: We studied hepatoma cells from GNMT knockout mice and analyzed the roles of liver kinase B1 (LKB1, STK11) signaling via 5′-adenosine monophosphateactivated protein kinase (AMPK) and Ras in regulating proliferation and transformation. RESULTS: Hepatoma cells from GNMT mice had defects in LKB1 signaling to AMPK, making them resistant to induction of apoptosis by adenosine 3′,5′-cyclic monophosphate activation of protein kinase A and calcium/calmodulin-dependent protein kinase kinase 2. Ras-mediated hyperactivation of LKB1 promoted proliferation of GNMT-deficient hepatoma cells and required mitogen-activated protein kinase 2 (ERK) and ribosomal protein S6 kinase polypeptide 2 (p90RSK). Ras activation of LKB1 required expression of RAS guanyl releasing protein 3 (RASGRP3). Reduced levels of GNMT and phosphorylation of AMPKα at Thr172 and increased levels of Ras, LKB1, and RASGRP3 in HCC samples from patients were associated with shorter survival times. CONCLUSIONS: Reduced expression of GNMT in mouse hepatoma cells and human HCC cells appears to increase activity of LKB1 and RAS; activation of RAS signaling to LKB1 and RASGRP3, via ERK and p90RSK, might be involved in liver carcinogenesis and be used as a prognostic marker. Reagents that disrupt this pathway might be developed to treat patients with HCC.",
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T1 - Hepatoma cells from mice deficient in glycine N-methyltransferase have increased RAS signaling and activation of liver kinase B1

AU - Martínez-López, Nuria

AU - García-Rodrgíuez, Juan L.

AU - Varela-Rey, Marta

AU - Gutiérrez, Virginia

AU - Fernández-Ramos, David

AU - Beraza, Naiara

AU - Aransay, Ana M.

AU - Schlangen, Karin

AU - Lozano, Juan Jose

AU - Aspichueta, Patricia

AU - Luka, Zigmund

AU - Wagner, Conrad

AU - Evert, Matthias

AU - Calvisi, Diego F.

AU - Lu, Shelly C.

AU - Mato, José M.

AU - Martínez-Chantar, María L.

PY - 2012/9

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N2 - BACKGROUND & AIMS: Patients with cirrhosis are at high risk for developing hepatocellular carcinoma (HCC), and their liver tissues have abnormal levels of S-adenosylmethionine (SAMe). Glycine N-methyltransferase (GNMT) catabolizes SAMe, but its expression is down-regulated in HCC cells. Mice that lack GNMT develop fibrosis and hepatomas and have alterations in signaling pathways involved in carcinogenesis. We investigated the role of GNMT in human HCC cell lines and in liver carcinogenesis in mice. METHODS: We studied hepatoma cells from GNMT knockout mice and analyzed the roles of liver kinase B1 (LKB1, STK11) signaling via 5′-adenosine monophosphateactivated protein kinase (AMPK) and Ras in regulating proliferation and transformation. RESULTS: Hepatoma cells from GNMT mice had defects in LKB1 signaling to AMPK, making them resistant to induction of apoptosis by adenosine 3′,5′-cyclic monophosphate activation of protein kinase A and calcium/calmodulin-dependent protein kinase kinase 2. Ras-mediated hyperactivation of LKB1 promoted proliferation of GNMT-deficient hepatoma cells and required mitogen-activated protein kinase 2 (ERK) and ribosomal protein S6 kinase polypeptide 2 (p90RSK). Ras activation of LKB1 required expression of RAS guanyl releasing protein 3 (RASGRP3). Reduced levels of GNMT and phosphorylation of AMPKα at Thr172 and increased levels of Ras, LKB1, and RASGRP3 in HCC samples from patients were associated with shorter survival times. CONCLUSIONS: Reduced expression of GNMT in mouse hepatoma cells and human HCC cells appears to increase activity of LKB1 and RAS; activation of RAS signaling to LKB1 and RASGRP3, via ERK and p90RSK, might be involved in liver carcinogenesis and be used as a prognostic marker. Reagents that disrupt this pathway might be developed to treat patients with HCC.

AB - BACKGROUND & AIMS: Patients with cirrhosis are at high risk for developing hepatocellular carcinoma (HCC), and their liver tissues have abnormal levels of S-adenosylmethionine (SAMe). Glycine N-methyltransferase (GNMT) catabolizes SAMe, but its expression is down-regulated in HCC cells. Mice that lack GNMT develop fibrosis and hepatomas and have alterations in signaling pathways involved in carcinogenesis. We investigated the role of GNMT in human HCC cell lines and in liver carcinogenesis in mice. METHODS: We studied hepatoma cells from GNMT knockout mice and analyzed the roles of liver kinase B1 (LKB1, STK11) signaling via 5′-adenosine monophosphateactivated protein kinase (AMPK) and Ras in regulating proliferation and transformation. RESULTS: Hepatoma cells from GNMT mice had defects in LKB1 signaling to AMPK, making them resistant to induction of apoptosis by adenosine 3′,5′-cyclic monophosphate activation of protein kinase A and calcium/calmodulin-dependent protein kinase kinase 2. Ras-mediated hyperactivation of LKB1 promoted proliferation of GNMT-deficient hepatoma cells and required mitogen-activated protein kinase 2 (ERK) and ribosomal protein S6 kinase polypeptide 2 (p90RSK). Ras activation of LKB1 required expression of RAS guanyl releasing protein 3 (RASGRP3). Reduced levels of GNMT and phosphorylation of AMPKα at Thr172 and increased levels of Ras, LKB1, and RASGRP3 in HCC samples from patients were associated with shorter survival times. CONCLUSIONS: Reduced expression of GNMT in mouse hepatoma cells and human HCC cells appears to increase activity of LKB1 and RAS; activation of RAS signaling to LKB1 and RASGRP3, via ERK and p90RSK, might be involved in liver carcinogenesis and be used as a prognostic marker. Reagents that disrupt this pathway might be developed to treat patients with HCC.

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KW - Liver Cancer

KW - Mouse Model

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