Analysis of aberrant methylation on promoter sequences of tumor suppressor genes and total DNA in sputum samples: a promising tool for early detection of COPD and lung cancer in smokers

Abstract

BackgroundChronic obstructive pulmonary disease (COPD) is a disorder associated to cigarette smoke and lung cancer (LC). Since epigenetic changes in oncogenes and tumor suppressor genes (TSGs) are clearly important in the development of LC. In this study, we hypothesize that tobacco smokers are susceptible for methylation in the promoter region of TSGs in airway epithelial cells when compared with non-smoker subjects. The purpose of this study was to investigate the usefulness of detection of genes promoter methylation in sputum specimens, as a complementary tool to identify LC biomarkers among smokers with early COPD.MethodsWe determined the amount of DNA in induced sputum from patients with COPD (n = 23), LC (n = 26), as well as in healthy subjects (CTR) (n = 33), using a commercial kit for DNA purification, followed by absorbance measurement at 260 nm. The frequency of CDKN2A, CDH1 and MGMT promoter methylation in the same groups was determined by methylation-specific polymerase chain reaction (MSP). The Fisher’s exact test was employed to compare frequency of results between different groups.ResultsDNA concentration was 7.4 and 5.8 times higher in LC and COPD compared to the (CTR) (p < 0.0001), respectively. Methylation status of CDKN2A and MGMT was significantly higher in COPD and LC patients compared with CTR group (p < 0.0001). Frequency of CDH1 methylation only showed a statistically significant difference between LC patients and CTR group (p < 0.05).ConclusionsWe provide evidence that aberrant methylation of TSGs in samples of induced sputum is a useful tool for early diagnostic of lung diseases (LC and COPD) in smoker subjects.Virtual slidesThe abstract MUST finish with the following text: Virtual Slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1127865005664160

Epigenetic targets for novel therapies of lung diseases

“…In patients with COPD DNA methylation is also altered in a complex pattern similar to that seen in asthma in which there is hypermethylation of some loci and hypomethylation of others (Guzmán et al, 2012; Qiu et al, 2012; Vucic et al, 2014). Genes that have been identified as differentially regulated in COPD include components of the PI3K/Akt and anti-oxidant NFE2-related factor-2 (Nrf2) pathways (Vucic et al, 2014).…”

Signaling network of lipids as a comprehensive scaffold for omics data integration in sputum of COPD patients

“…of single nucleotide polymorphisms and methylations using primarily patients with COPD including the COPDgene study were also considered [34][35][36].The reported single nucleotide polymorphisms from Genome-Wide Association investigation in the COPDgene study were not involved in lipid metabolism and signaling pathways.…”

Environmental Toxicants, Epigenetics, and Cancer

“…For example, methylation status of CDKN2A, MGMT, and CDH1 were found to be signifi cantly higher in sputum of smokers with lung cancer compared to smokers without lung cancer, as analyzed by methylation-specifi c polymerase chain reaction (MSP) (Guzmán et al 2012 ). Since many researchers are searching for potential DNA methylation-based biomarkers for early detection of cancer, understanding the differences in DNA methylation patterns between patients with and without cancer, in the context of smoking status and other confounders, is necessary.…”