Expression data from AFB1-treated GNMT knockout mice
Ontology highlight
ABSTRACT: We report that liver nodules from 5/8 (62.5%) male and 4/5 (80%) female Gnmt-/- mice were diagnosed as having HCC. Microarray analysis showed that genes involved in the following pathways were deregulated in different stages of tumorigenesis: Methylation, metabolism, signal transduction, cell proliferation, and cell adhesion. This study reveals that GNMT plays an important role in the prevention of hepatotumorigenesis through regulating detoxification pathways. We postulate that GNMT is a stress-responsive protein and its expression may account for the gender difference of the susceptibility to liver cancer. Liver tissues from aflatoxin B1 (AFB1)-treated wild-type or Gnmt knockout mice at 11weeks old were used for RNA extraction and hybridization on Affymetrix microarrays. Total RNA were mixed in equal proportion from 3 mice.
Project description:Hepatocellular carcinoma (HCC) is the first cause of death in cirrhotic patients. Liver cirrhosis at a high risk of HCC has abnormal S-Adenosylmethionine (SAMe) levels. Catabolism of SAMe is mainly mediated by Glycine N-methyltransferase (GNMT), Lack in GNMT expression leads to epigenetic regulation of critical carcinogenesis pathways and mounting evidence assigns an essential role of GNMT in HCC. Methods: Here we have studied the role of LKB1-AMPK and RAS in the proliferation and transformation of GNMT-deficient HCC. Results. GNMT-deficient HCC was characterized by LKB1-AMPK misconnection, leading to resistance of apoptosis response mediated by a positive regulation of cAMP-PKA-CaMKKM-NM-2 cascade. Additionally, Ras-mediated hyperactivation of LKB1 contributes to the proliferation of GNMT-deficient HCC in an ERK/p90RSK-dependent manner. The observed LKB1-induced Ras activation, was due to the regulation of RASGRP3 expression. Notably, the human HCC tumors with poorer prognosis showed the lowest levels of GNMT, p-AMPKM-NM-1(Thr172) and the highest activation of Ras/LKB1/RASGRP3 axis. The present data suggest a correlation between LKB1 and RAS activity in a context of HCC with low GNMT expression, indicating that activation of the RAS/LKB1/RASGRP3 cascade might possess an important prognostic role in human liver cancer. Furthermore, these findings open the possibility to design new therapeutic strategies for the treatment of liver cancer. HCC induced wild-type or Gnmt knockout mice at 3 weeks old were used for RNA extraction and hybridization on Illumina microarrays. The study comprises three groups of samples: OKER cell line(n=3), GNMT-KO mouse hepatocytes (n=3) ,GNMT-WT mouse hepatocytes(n=3)
Project description:We report that liver nodules from 5/8 (62.5%) male and 4/5 (80%) female Gnmt-/- mice were diagnosed as having HCC. Microarray analysis showed that genes involved in the following pathways were deregulated in different stages of tumorigenesis: Methylation, metabolism, signal transduction, cell proliferation, and cell adhesion. This study reveals that GNMT plays an important role in the prevention of hepatotumorigenesis through regulating detoxification pathways. We postulate that GNMT is a stress-responsive protein and its expression may account for the gender difference of the susceptibility to liver cancer.
Project description:We evaluated aflatoxin B1-induced liver tumor promotion by H. hepaticus. Microarrays of liver and cecum from female mice were used to evaluate the individual and combined transcriptional effects of AFB1 and H. hepaticus Experiment Overall Design: C3H/HeN mice were inoculated with 7 ug/g BW AFB1 or vehicle IP at 10 days of age, and gavaged with H. hepaticus or broth at 3 weeks; necropsied at 40 weeks
Project description:We report that 7 of 7 female Gnmt-/- mice developed hepatocellular carcinoma (HCC), the most common form of liver cancer, at the mean age of 16.1 months. In contrast, only one-third (2/6) of male Gnmt-/- mice had HCC, the remaining had either premature death or liver necrosis. Microarray analysis showed that genes involved in the following pathways were deregulated in different stages of tumorigenesis: S-adenosylmethionine (SAM)-dependent methyltransferases, metabolism, signal transduction, cell proliferation, cell adhesion and immune responses. This study reveals that GNMT plays an important role in the prevention of hapatotumorigenesis through regulating DNA methylaiton and oxidative stress signaling pathways. We postulate that GNMT is a stress-responsive protein and its expression may account for the gender difference of the susceptibility to liver cancer. Keywords: Gnmt knockout
Project description:We report that 7 of 7 female Gnmt-/- mice developed hepatocellular carcinoma (HCC), the most common form of liver cancer, at the mean age of 16.1 months. In contrast, only one-third (2/6) of male Gnmt-/- mice had HCC, the remaining had either premature death or liver necrosis. Microarray analysis showed that genes involved in the following pathways were deregulated in different stages of tumorigenesis: S-adenosylmethionine (SAM)-dependent methyltransferases, metabolism, signal transduction, cell proliferation, cell adhesion and immune responses. This study reveals that GNMT plays an important role in the prevention of hapatotumorigenesis through regulating DNA methylaiton and oxidative stress signaling pathways. We postulate that GNMT is a stress-responsive protein and its expression may account for the gender difference of the susceptibility to liver cancer. Keywords: Gnmt knockout Liver tissues from wild-type or Gnmt knockout mice at young ages, devoloping dysplasia nodules or HCC were used for RNA extraction and hybridization on Affymetrix microarrays. For 11 weeks old mice, total RNA were mixed in equal proportion from 3 mice.
Project description:Viral hepatitis and aflatoxin B1 (AFB1) exposure are common risk factors for hepatocellular carcinoma (HCC). The incidence of HCC in individuals co-exposed to hepatitis C (HCV) or B virus and AFB1 is greater than could be explained by the additive effect, yet the mechanisms are poorly understood due to lack of an animal model. This study investigated the outcomes and mechanisms of combined exposure to HCV and AFB1. We hypothesized that HCV transgenic (HCV-Tg; expressing core, E1, E2, and p7, nucleotides 342-2771) mice will be prone to hepatocarcinogenesis when exposed to AFB1. Neonatal (7 days old) HCV-Tg or C57BL/6J wild-type mice were exposed to AFB1 (6 ug/g bw) or tricaprylin vehicle (15 ul/g bw) and male offspring were followed for up to 12 months. No liver lesions were observed in vehicle-treated wild type or HCV-Tg mice. Tumors (adenomas or carcinomas) and preneoplastic lesions (hyperplasia or foci) were observed in 22.5% (9 of 40) of AFB1-treated wild-type mice. In HCV-Tg, the incidence of tumorous or pre-tumorous lesions was significantly elevated (50%, 18 of 36), with the difference largely due to a 2.5-fold increase in the incidence of adenomas (30.5% vs 12.5%). While oxidative stress and steato-hepatisis were observed in both AFB1-treated groups, molecular changes indicative of the enhanced inflammatory response and altered lipid metabolism were more pronounced in HCV-Tg mice. In summary, HCV proteins core, E1, E2 and p7 are sufficient to reproduce the additive co-carcinogenic effect of HCV and AFB1 which is a known clinical phenomenon. HCV transgenic mice (SL-139 strain, pAlbSVPA-HCV-S, containing the structural genes core, E1, E2, and p7, nucleotides 342-2771 of HCV genotype 1b, strain N, under the control of the murine albumin promoter/enhancer) on C57BL/6J (Jackson Laboratory, Bar Harbor, ME) background were previously reported in Lerat et al (Lerat et al., Gastroenterology 122, 352-365, 2002). Transgenic animals were identified after weaning as detailed in Korenaga et al (Korenaga et al., J Biol. Chem. 280, 37481-37488, 2005). Neonatal (7 days old) mice were administered a single dose of AFB1 (6 ug/g bw) or tricaprylin vehicle (15 ul/g bw) by intra-peritoneal injection. Male mice were maintained on the regular animal chow with free access to food and water for up to 12 months. All animal experiments were approved by the UNC Animal Care and Use Committee. There were 20 liver samples used for microarray analysis (12 month time point). All samples were run in one batch. There are 4 groups: WT/Control (4 samples - all biological replicates, i.e., different animals); WT/AFB1 (6 samples); HCV/Control (4 samples); HCV/AFB1 (6 samples). This was a 2 color design with a common reference mRNA. No dye swaps or replicate arrays were included.
Project description:We report that Gnmt-/- mice have abnormal behavior including spontaneous locomotion activity, PPI, TST and FST. Microarray analysis showed that genes expression profiles in male Gnmt -/- mice Keywords: Gnmt knockout
Project description:Applied de novo assembly, both protein coding and non-coding RNAs were profiled in AFB1 induced HCC and AFB1 resistant liver sample. Compared with normal liver, the perturbation on transcriptome was revealed in multiple aspects, implying the potential mechanism of toxic resistance.
Project description:Hepatocellular carcinoma (HCC) is the first cause of death in cirrhotic patients. Liver cirrhosis at a high risk of HCC has abnormal S-Adenosylmethionine (SAMe) levels. Catabolism of SAMe is mainly mediated by Glycine N-methyltransferase (GNMT), Lack in GNMT expression leads to epigenetic regulation of critical carcinogenesis pathways and mounting evidence assigns an essential role of GNMT in HCC. Methods: Here we have studied the role of LKB1-AMPK and RAS in the proliferation and transformation of GNMT-deficient HCC. Results. GNMT-deficient HCC was characterized by LKB1-AMPK misconnection, leading to resistance of apoptosis response mediated by a positive regulation of cAMP-PKA-CaMKKβ cascade. Additionally, Ras-mediated hyperactivation of LKB1 contributes to the proliferation of GNMT-deficient HCC in an ERK/p90RSK-dependent manner. The observed LKB1-induced Ras activation, was due to the regulation of RASGRP3 expression. Notably, the human HCC tumors with poorer prognosis showed the lowest levels of GNMT, p-AMPKα(Thr172) and the highest activation of Ras/LKB1/RASGRP3 axis. The present data suggest a correlation between LKB1 and RAS activity in a context of HCC with low GNMT expression, indicating that activation of the RAS/LKB1/RASGRP3 cascade might possess an important prognostic role in human liver cancer. Furthermore, these findings open the possibility to design new therapeutic strategies for the treatment of liver cancer.
Project description:We report that Gnmt-/- mice have abnormal behavior including spontaneous locomotion activity, PPI, TST and FST. Microarray analysis showed that genes expression profiles in male Gnmt -/- mice Keywords: Gnmt knockout Cerebral cortex tissues from wild-type or Gnmt knockout mice were used for RNA extraction and hybridization on Affymetrix microarrays. For 4 weeks old mice, total RNA were mixed in equal proportion from 3 mice.