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Expression profiling of 40 NSCLC cell lines

ABSTRACT: INTRODUCTION: CDKN2A (p16) inactivation is common in lung cancer and occurs via homozygous deletions, methylation of promoter region, or point mutations. Although p16 promoter methylation has been linked to KRAS mutation and smoking, the associations between p16 inactivation mechanisms and other common genetic mutations and smoking status are still controversial or unknown. METHODS: We determined all three p16 inactivation mechanisms with the use of multiple methodologies for genomic status, methylation, RNA, and protein expression, and correlated them with EGFR, KRAS, STK11 mutations and smoking status in 40 cell lines and 45 tumor samples of primary non-small-cell lung carcinoma. We also performed meta-analyses to investigate the impact of smoke exposure on p16 inactivation. RESULTS: p16 inactivation was the major mechanism of RB pathway perturbation in non-small-cell lung carcinoma, with homozygous deletion being the most frequent method, followed by methylation and the rarer point mutations. Inactivating mechanisms were tightly correlated with loss of mRNA and protein expression. p16 inactivation occurred at comparable frequencies regardless of mutational status of EGFR, KRAS, and STK11, however, the major inactivation mechanism of p16 varied. p16 methylation was linked to KRAS mutation but was mutually exclusive with EGFR mutation. Cell lines and tumor samples demonstrated similar results. Our meta-analyses confirmed a modest positive association between p16 promoter methylation and smoking. CONCLUSION: Our results confirm that all the inactivation mechanisms are truly associated with loss of gene product and identify specific associations between p16 inactivation mechanisms and other genetic changes and smoking status.

ORGANISM(S): Homo sapiens

PROVIDER: GSE63882 | GEO | 2015/06/22

SECONDARY ACCESSION(S): PRJNA269313

REPOSITORIES: GEO

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Project description:INTRODUCTION: CDKN2A (p16) inactivation is common in lung cancer and occurs via homozygous deletions, methylation of promoter region, or point mutations. Although p16 promoter methylation has been linked to KRAS mutation and smoking, the associations between p16 inactivation mechanisms and other common genetic mutations and smoking status are still controversial or unknown. METHODS: We determined all three p16 inactivation mechanisms with the use of multiple methodologies for genomic status, methylation, RNA, and protein expression, and correlated them with EGFR, KRAS, STK11 mutations and smoking status in 40 cell lines and 45 tumor samples of primary non-small-cell lung carcinoma. We also performed meta-analyses to investigate the impact of smoke exposure on p16 inactivation. RESULTS: p16 inactivation was the major mechanism of RB pathway perturbation in non-small-cell lung carcinoma, with homozygous deletion being the most frequent method, followed by methylation and the rarer point mutations. Inactivating mechanisms were tightly correlated with loss of mRNA and protein expression. p16 inactivation occurred at comparable frequencies regardless of mutational status of EGFR, KRAS, and STK11, however, the major inactivation mechanism of p16 varied. p16 methylation was linked to KRAS mutation but was mutually exclusive with EGFR mutation. Cell lines and tumor samples demonstrated similar results. Our meta-analyses confirmed a modest positive association between p16 promoter methylation and smoking. CONCLUSION: Our results confirm that all the inactivation mechanisms are truly associated with loss of gene product and identify specific associations between p16 inactivation mechanisms and other genetic changes and smoking status. 40 NSCLC cell lines were profiled on Illumina WG6-V3 expression arrays. They consist of 4 groups of 10 cell lines each: non-smokers with EGFR mutation, non-smokers with EGFR wild-type, smokers with KRAS mutation, smokers with KRAS wild-type. Note that smoking status is not always clear.

Project description:Background: The most important risk factors for head and neck squamous carcinoma (HNSCC) are tobacco smoking and alcohol consumption, while subgroups are caused by infection with human papillomaviruses (HPV) or Epstein-Barr virus (EBV). Here, we studied alterations of somatic copy-number in whole genome, p16 protein and TP53 mutations by alcohol drinking, smoking and viral infections. Methods: We conducted a prospective cohort study. DNA obtained from tumors and margin samples as well as peripheral blood was assayed by array comparative genomic hybridization using Agilent Whole Human Genome 180K. Mutations of p53 gene by direct sequencing, detection of HPV by polymerase-chain-reaction (PCR), quantification of EBV by reverse transcription-PCR and p16 immunohistochemical (IHC) staining were also performed. prospective cohort study: 225 tumor samples were analyzed by Agilent-022060 SurePrint G3 Human CGH miroarray 4x180K. Log2 Ratio (tumor sample DNA/normal DNA) were compared among none alcohol drinkers, moderate alcohol drinkers, heavy alcohol drinkers, none smokers, moderate smokers, heavy smokers and both. Sample characteristics weres scored as following; Human Papilloma Virus Infection (gene detected by PCR in tumor sample): positive=1; negative=0 p16 protein immunohistochemistry: positive=1; negative=0 tumor grade: matured=0; moderate=1; immature=2 Radiotherapy with or without chemotherapy after operation: performed =1; not performed =0 Recurrence/relapse: rec =1; not rec =0 suvival status:death=1; survive=0 smoking status (Pack year of smoking): none smoker=0; pack-year <20 = 1 (moderate smoker); pack-year <=20 = 2 (heavy smoker) alcohol drinking: Alcohol drinkers were divided into non-drinker or less than one drink per day =0: one and more but less than two drinks per day = moderate drinker 1: two and more drinks per day=heavy drinker 2: during the 20 years preceding their treatment for HNSCC. One drink was defined as containing approximately 10g of alcohol, which is considered equal to 30 ml of hard liquor, 100 ml of wine containing 12% alcohol, or 360 ml of beer.

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Expression profiling of 40 NSCLC cell lines

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