Unknown,Transcriptomics,Genomics,Proteomics

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Array data obtained during development of chemically induced hepatocellular carcinoma in rat

ABSTRACT: Although disruption of mitochondrial function has been associated with energetic deregulation in cancer, the chronological changes in mitochondria during cancer development remain unclear. With the aim to assess the role of mitochondria throughout cancer development, we analyzed samples chronologically obtained from induced hepatocellular carcinoma (HCC) in rats. In our analyses, we integrated mitochondrial proteomic data, mitochondrial metabolomic data and nuclear genome transcriptomic data. We used pathway over-representation and weighted gene co-expression network analysis (WGCNA) to integrate expression profiles of genes, miRNAs, proteins and metabolite levels throughout HCC development. Our results show that mitochondria are dynamic organelles presenting specific modifications in different stages of HCC development. For carcinogenesis, a modified resistant hepatocyte model was used. Rats were initiated with diethylnitrosamine (DEN) (200 mg/kg of body weight) at day 0. Then, 2-acetylaminofluorene (AAF) was administered (20 mg/kg per dose) at days 7, 8 and 9, followed by 3/5 partial hepatectomy (PH) at day 10. Three control groups of non-treated animals were sacrificed by exsanguination on the first day and at 9 and 18 months after the beginning of the experiment. Treated animals were sacrificed at 1, 7, 11 and 16 days and at 1, 9 and 18 months. Their livers were excised, washed in physiological saline solution, frozen with liquid nitrogen in 2-methyl butane and stored at -80°C. Once selected and separately collected nodular, tumoral and its adjacent tissues, total RNA was isolated using TriPureIsolation Reagent (Roche) according to the manufacturer’s protocol. The microarray analysis was performed using GeneChip Rat Exon 1.0 ST Arrays. Four replicas for each condition and controls were analyzed. This created 11 pairwise contrasts for the differential expression analysis. We grouped all evaluated conditions in three categories: i) early stages, including samples obtained since day one until one month after treatment, these were compared against rats without treatment sacrificed the first day; ii) tumor, nodular and its adjacent tissues obtained from nine months rats were compared against rats without treatment of the same age; and iii) tumor and its adjacent tissues obtained from eighteen months rats were compared against rats without treatment of the same age.

ORGANISM(S): Rattus norvegicus

SUBMITTER: Rafael Montiel

PROVIDER: E-MTAB-9983 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Although disruption of mitochondrial function has been associated with energetic deregulation in cancer, the chronological changes in mitochondria during cancer development remain unclear. With the aim to assess the role of mitochondria throughout cancer development, we analyzed samples chronologically obtained from induced hepatocellular carcinoma (HCC) in rats. In our analyses, we integrated mitochondrial proteomic data, mitochondrial metabolomic data and nuclear genome transcriptomic data. We used pathway over-representation and weighted gene co-expression network analysis (WGCNA) to integrate expression profiles of genes, miRNAs, proteins and metabolite levels throughout HCC development. Our results show that mitochondria are dynamic organelles presenting specific modifications in different stages of HCC development. For carcinogenesis, a modified resistant hepatocyte model was used. Rats were initiated with diethylnitrosamine (DEN) (200 mg/kg of body weight) at day 0. Then, 2-acetylaminofluorene (AAF) was administered (20 mg/kg per dose) at days 7, 8 and 9, followed by 3/5 partial hepatectomy (PH) at day 10. Three control groups of non-treated animals were sacrificed by exsanguination on the first day and at 9 and 18 months after the beginning of the experiment. Treated animals were sacrificed at 1, 7, 11 and 16 days and at 1, 9 and 18 months. Their livers were excised, washed in physiological saline solution, frozen with liquid nitrogen in 2-methyl butane and stored at -80°C. Once selected and separately collected nodular, tumoral and its adjacent tissues, total RNA was isolated using TriPureIsolation Reagent (Roche) according to the manufacturer’s protocol. The microarray analysis was performed using GeneChip Rat Exon 1.0 ST Arrays. Four replicas for each condition and controls were analyzed. This created 11 pairwise contrasts for the differential expression analysis. We grouped all evaluated conditions in three categories: i) early stages, including samples obtained since day one until one month after treatment, these were compared against rats without treatment sacrificed the first day; ii) tumor, nodular and its adjacent tissues obtained from nine months rats were compared against rats without treatment of the same age; and iii) tumor and its adjacent tissues obtained from eighteen months rats were compared against rats without treatment of the same age.

Project description:Hepatocellular carcinoma (HCC) is the leading cause of cancer-related deaths worldwide, reflecting the need for a better understanding of hepatocarcinogenesis. In this study, we examined the genome-wide expression profiles of both miRNAs and mRNAs from paired tumor and adjacent non-tumor tissues from a cohort of 96 HCC patients in Hong Kong where hepatitis B virus (HBV) is endemic. The comprehensive analysis of the coordinate expression of miRNAs and mRNAs reveals that miR-122 is under-expressed in HCC and that it is an important regulator for normal mitochondrial metabolism. A decreased level of miR-122 leads to an increase in expression of miR-122 seed-matched genes, a loss of mitochondrial metabolic function, and a decrease in the expression of many miR-122 secondary targets. These secondary targets are prognostic markers for HCC patients. Transcriptome profiling data from an additional 180 HCC and 40 liver cirrhotic patients in the same cohort were used to confirm the anti-correlation of miR-122 primary and secondary target gene sets. To test the HCC findings in normal mouse liver, we used an antagomir against miR-122 and identified altered gene expression profiling by microarray analysis in mouse in vivo experiments. The mouse data recapitulated the human HCC findings. Our anti-miR122 data further provided a direct link between increases in the mRNA levels of miR-122 controlled genes and impairments of mitochondrial metabolism. In summary, we find miR-122 loss may be detrimental to mitochondrial-related metabolisms in sustaining critical liver function and contribute to the morbidity and mortality of liver cancer patients. Mouse liver profiling: In one treatment regimen, four animals were given four doses of 100mg ASO/kg body weight, administered every other day, and sacrificed one day after the last dose. Four animals treated for four weeks were treated twice weekly with 50mg ASO/kg body weight, and sacrificed two days after the last dose. Mice were sacrificed in the morning, and liver was removed for further analysis. Samples from oligonucleotide-treated mice were referenced against samples from saline-treated mice in fluor-reversed pairs. Human liver profiling: For human HCC patient samples, 192 samples -- 96 resected tumor and 96 adjacent non-tumor liver tissues -- were collected from 96 patients who had undergone hepatectomy for curative treatment of HCC at Queen Mary Hospital, Pokfulam, Hong Kong between 1990 and 2007. Informed consents were obtained from patients regarding the use of the liver specimens for research. Samples were hybridized to Affymetrix arrays for mRNA profiling and were analyzed by quantitative PCR for microRNA profiling.

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Array data obtained during development of chemically induced hepatocellular carcinoma in rat

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