|
| Status |
Public on Jun 09, 2010 |
| Title |
HKU_Liver_0115_TU_RS-258827_22125_S3_UPDATED |
| Sample type |
RNA |
| |
|
| Source name |
liver
|
| Organism |
Homo sapiens |
| Characteristics |
individual: 115
tissue: liver tumor
|
| Extracted molecule |
total RNA |
| Extraction protocol |
Samples are processed in parallel in 96-well plates to minimize potential variation. Reaction purification is achieved using magnetic binding beads for cDNA and Qiagen RNeasy kits for cRNA purification.
|
| Label |
biotin
|
| Label protocol |
The reverse transcription incorporates biotin moieties that are later labeled with phycoerythrin. After amplification, samples are put through a controlled fragmentation to improve hybridization sensitivity and consistency. The labeled molecules are biotinylated-cDNA.
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| |
|
| Hybridization protocol |
GeneChip microarrays are loaded with the fragmented target sample/hybridization buffer mix using standard manual techniques. Arrays are hybridized for 18 hours at 45?C with vigorous mixing. Unbound sample is removed and staining is accomplished through the binding of streptavidin conjugated phycoerythrin to the hybridized target. Excess label is removed. Washing and staining steps are performed by the Affymetrix FS450 fluidics station using standard protocols.
|
| Scan protocol |
Arrays are scanned using a GeneChip Scanner 3000 7G with a 48 array autoloader. The scanner maintains the optimal temperature for the arrays prior to and during scanning.
|
| 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.
|
| Data processing |
Data were loaded into the Rosetta Resolver? system (Rosetta Biosoftware, Seattle, WA) and processed using the RMA algorithm (http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=12582260). Intensities were calculated based on RMA, a Rosetta-developed error, and a MAS-5 p-value. The Rosetta-developed error is used in the calculation of xdev for the ratio p-values as described in section 2.2 (http://bioinformatics.oxfordjournals.org/cgi/content/full/22/9/1111).
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| |
|
| Submission date |
May 30, 2010 |
| Last update date |
Jun 08, 2010 |
| Contact name |
Julja Burchard |
| Organization name |
Merck & Co., Inc.
|
| Department |
Computational & Systems Biology
|
| Street address |
33 Avenue Louis Pasteur
|
| City |
Boston |
| State/province |
MA |
| ZIP/Postal code |
02176 |
| Country |
USA |
| |
|
| Platform ID |
GPL6793 |
| Series (1) |
| GSE22058 |
miR-122 as a Regulator of Mitochondrial Metabolic Gene Network in Hepatocellular Carcinoma |
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