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Transcription by array of human buccal mucosa from smokers and non-smokers

ABSTRACT: A tissue like buccal mucosa (from cheek swabs) would be an ideal sample material for rapid, easy collection for testing of biomarkers as an alternative to blood. A limited number of studies, primarily in the smoker/oral cancer literature, address this tissue's efficacy for quantitative PCR or microarray gene expression analysis. In this study both qPCR and microarray analyses were used to evaluate gene expression in buccal cells. An initial study comparing blood and buccal cells from the same individuals looked at relative amounts of four genes. The RNA isolated from buccal cells was degraded but was of sufficient quality to be used with RT-qPCR to detect expression of specific genes. Second, buccal cell RNA was used for microarray-based differential gene expression studies by comparing gene expression between smokers and nonsmokers. The isolation and amplification protocol allowed use of 150-fold less buccal cell RNA than had been reported previously with human microarrays. We report here the finding of a small number of significant gene expression differences between smokers and nonsmokers, using buccal cells as target material. Additionally, Gene Set Enrichment Analysis confirmed that these genes were changing expression in the same pattern as seen in an earlier buccal cell study performed by another group. Our results suggest that in spite of a high degree of RNA degradation, buccal cells from cheek mucosa could be used to detect differential gene expression between smokers and nonsmokers. However the RNA degradation, increase in sample variability and microarray failure rate show that buccal samples should be used with caution as source material in expression studies. Samples were collected from eight subjects, four smokers (Sm)and four nonsmokers (NS). Each cheek was sampled creating an a and b sample for each subject which is reflected in the array name. All samples were isolated separately for total RNA. Each was hybridzed to microarrays to examine for differential gene expression between smokers and nonsmokers. There are 14 total samples in the main dataset (Set 2). One cheek sample failed in microarray analysis for two individuals, 08BCNS23 a and 08BCSm27 a, and so are not included here. A sample set (Set 1) was created which contains the four samples shown in this file. They represent repeated sampling of both cheeks for two individuals to test for reproducibility. There is a separate RMA file and metadata file (this file) for these data. These included samples 08BC11Sm a and b, a smoker, and 08BC12NSa and b a nonsmoker.

ORGANISM(S): Homo sapiens

SUBMITTER: Kupfer DM

PROVIDER: S-ECPF-GEOD-16149 | biostudies-other | 2010

REPOSITORIES: biostudies-other

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Project description:Upregulation of Expression of the Ubiquitin Carboxyl Terminal Hydrolase L1 Gene in Human Airway Epithelium of Cigarette Smokers; The microarray data deposited here is from 11 HG-U133A GeneChips, from 5 normal non-smokers and 6 phenotypic normal smokers, large airways. Samples from the small airways of these individuals have been obtained and analyzed using the HG-U133A GeneChip; the small airway samples are in GEO Accession Number GSE 3320, and the data analysis is described in Harvey, B-G; Heguy, A.; Leopold, P.L.; Carolan, B.; Ferris, B. and Crystal R.G. Modification of Gene Expression of the Small Airway Epithelium in Response to Cigarette Smoking. J. Mol. Med (in press). These data are part of a study aimed at understanding how cigarette smoking modifies neuroendocrine cells, in which microarray analysis with TaqMan confirmation was used to assess airway epithelial samples obtained by fiberoptic bronchoscopy from 81 individuals (normal nonsmokers, normal smokers, smokers with early COPD and smokers with established COPD). Of 11 genes considered to be neuroendocrine cell-specific, only ubiquitin C-terminal hydrolase L1(UCHL1), a member of the ubiquitin proteasome pathway, was consistently upregulated in smokers compared to nonsmokers. Up-regulation of UCHL1 at the protein level was observed with immunohistochemistry of bronchial biopsies of smokers compared to nonsmokers. Interestingly, however, while UCHL1 expression was present only in neuroendocrine cells of the airway epithelium in nonsmokers, UCHL1 expression was also expressed in ciliated epithelial cells in smokers, an intriguing observation in light of recent observations that ciliated cells can are capable of transdifferentiating to other airway epithelium. In the context that UCHL1 is involved in the degradation of unwanted, misfolded or damaged proteins within the cell and is overexpressed in >50% of lung cancers, its overexpression in chronic smokers may represent an early event in the complex transformation from normal epithelium to overt malignancy. Experiment Overall Design: comparison of gene expression in airway epithelial cells of the large airways of phenotypic normal smokers vs normal non-smokers

Project description:Upregulation of Expression of the Ubiquitin Carboxyl Terminal Hydrolase L1 Gene in Human Airway Epithelium of Cigarette Smokers; The microarray data deposited here is from 44 HuGeneFL GeneChips, from 9 normal non-smokers and 13 phenotypic normal smokers, large airways, 2 samples per individual, one from the right lung and one from the left lung. These samples were previously described in Hackett NR, Heguy A, Harvey BG, O'Connor TP, Luettich K, Flieder DB, Kaplan R, Crystal RG. Variability of antioxidant-related gene expression in the airway epithelium of cigarette smokers. Am J Respir Cell Mol Biol. 2003 29:331-43 and in Heguy A, Harvey BG, O'Connor TP, Hackett NR, Crystal RG. Sampling-dependent up-regulation of gene expression in sequential samples of human airway epithelial cells. Mol Med. 2003 9:200-8. These data are part of a study aimed at understanding how cigarette smoking modifies neuroendocrine cells, in which microarray analysis with TaqMan confirmation was used to assess airway epithelial samples obtained by fiberoptic bronchoscopy from 81 individuals (normal nonsmokers, normal smokers, smokers with early COPD and smokers with established COPD). Of 11 genes considered to be neuroendocrine cell-specific, only ubiquitin C-terminal hydrolase L1(UCHL1), a member of the ubiquitin proteasome pathway, was consistently upregulated in smokers compared to nonsmokers. Up-regulation of UCHL1 at the protein level was observed with immunohistochemistry of bronchial biopsies of smokers compared to nonsmokers. Interestingly, however, while UCHL1 expression was present only in neuroendocrine cells of the airway epithelium in nonsmokers, UCHL1 expression was also expressed in ciliated epithelial cells in smokers, an intriguing observation in light of recent observations that ciliated cells can are capable of transdifferentiating to other airway epithelium. In the context that UCHL1 is involved in the degradation of unwanted, misfolded or damaged proteins within the cell and is overexpressed in >50% of lung cancers, its overexpression in chronic smokers may represent an early event in the complex transformation from normal epithelium to overt malignancy. Experiment Overall Design: comparison of gene expression in airway epithelial cells of the large airways of phenotypic normal smokers vs normal non-smokers

Project description:BackgroundGene expression changes resulting from conditions such as disease, environmental stimuli, and drug use, can be monitored in the blood. However, a less invasive method of sample collection is of interest because of the discomfort and specialized personnel necessary for blood sampling especially if multiple samples are being collected. Buccal mucosa cells are easily collected and may be an alternative sample material for biomarker testing. A limited number of studies, primarily in the smoker/oral cancer literature, address this tissue's efficacy as an RNA source for expression analysis. The current study was undertaken to determine if total RNA isolated from buccal mucosa could be used as an alternative tissue source to assay relative gene expression.MethodsTotal RNA was isolated from swabs, reverse transcribed and amplified. The amplified cDNA was used in RT-qPCR and microarray analyses to evaluate gene expression in buccal cells. Initially, RT-qPCR was used to assess relative transcript levels of four genes from whole blood and buccal cells collected from the same seven individuals, concurrently. Second, buccal cell RNA was used for microarray-based differential gene expression studies by comparing gene expression between a group of female smokers and nonsmokers.ResultsAn amplification protocol allowed use of less buccal cell total RNA (50 ng) than had been reported previously with human microarrays. Total RNA isolated from buccal cells was degraded but was of sufficient quality to be used with RT-qPCR to detect expression of specific genes. We report here the finding of a small number of statistically significant differentially expressed genes between smokers and nonsmokers, using buccal cells as starting material. Gene Set Enrichment Analysis confirmed that these genes had a similar expression pattern to results from another study.ConclusionsOur results suggest that despite a high degree of degradation, RNA from buccal cells from cheek mucosa could be used to detect differential gene expression between smokers and nonsmokers. However the RNA degradation, increase in sample variability and microarray failure rate show that buccal samples should be used with caution as source material in expression studies.

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Transcription by array of human buccal mucosa from smokers and non-smokers

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