BackgroundDNA methylation regulates together with other epigenetic mechanisms the transcriptional activity of genes and is involved in the pathogenesis of malignant diseases including lung cancer. In non-small cell lung cancer (NSCLC) various tumor suppressor genes are already known to be tumor-specifically methylated. However, from the vast majority of a large number of genes which were identified to be tumor-specifically methylated, tumor-specific methylation was unknown so far. Thus, the major aim of this study was to investigate in detail the mechanism(s) responsible for transcriptional regulation of the genes SPAG6 and L1TD1 in NSCLCs.MethodsWe analysed publically available RNA-sequencing data and performed gene expression analyses by RT-PCR. DNA methylation analyses were done by methylation-sensitive high-resolution melt analyses and bisulfite genomic sequencing. We additionally investigated protein expression using immunohistochemistry. Cell culture experiments included tumor cell growth, proliferation, viability as well as colony formation assays. Moreover, we performed xenograft experiments using immunodeficient mice.ResultsWe observed frequent downregulation of SPAG6 and L1TD1 mRNA expression in primary tumor (TU) samples compared to corresponding non-malignant lung tissue (NL) samples of NSCLC patients. We furthermore observed re-expression of both genes after treatment with epigenetically active drugs in most NSCLC cell lines with downregulated SPAG6 and L1TD1 mRNA expression. Frequent tumor-specific DNA methylation of SPAG6 and L1TD1 was detected when we analysed TU and corresponding NL samples of NSCLC patients. ROC curve analyses demonstrated that methylation of both genes is able to distinguish between TU and NL samples of these patients. Immunohistochemistry revealed a close association between SPAG6/L1TD1 methylation and downregulated protein expression of these genes. Moreover, by performing functional assays we observed reduced cell growth, proliferation and viability of pCMV6-L1TD1 transfected NSCLC cells. In addition, reduced volumes of tumors derived from pCMV6-L1TD1 compared to pCMV6-ENTRY transfected NCI-H1975 cells were seen in a xenograft tumor model.ConclusionsOverall, our results demonstrate that SPAG6 and L1TD1 are tumor-specifically methylated in NSCLCs and that DNA methylation is involved in the transcriptional regulation of these genes. Moreover, in vitro as well as in vivo experiments revealed tumor-cell growth suppressing properties of L1TD1 in NSCLC cells.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-016-0568-5) contains supplementary material, which is available to authorized users.
Intraoperative ECMO results in superior survival when compared with transplantation without any extracorporeal support. The concept of prophylactic postoperative ECMO prolongation is associated with excellent outcomes in recipients with pulmonary hypertension and in patients with questionable graft function at the end of implantation.
Purpose: The major aim of this study was to investigate the role of DNA methylation (referred to as methylation) on miRNA silencing in non-small cell lung cancers (NSCLC).Experimental Design: We conducted microarray expression analyses of 856 miRNAs in NSCLC A549 cells before and after treatment with the DNA methyltransferase inhibitor 5-aza-2 0 -deoxycytidine (Aza-dC)and with a combination of Aza-dC and the histone deacetylase inhibitor trichostatin A. miRNA methylation was determined in 11 NSCLC cell lines and in primary tumors and corresponding nonmalignant lung tissue samples of 101 patients with stage I-III NSCLC.Results: By comparing microarray data of untreated and drug-treated A549 cells, we identified 33 miRNAs whose expression was upregulated after drug treatment and which are associated with a CpG island. Thirty (91%) of these miRNAs were found to be methylated in at least 1 of 11 NSCLC cell lines analyzed. Moreover, miR-9-3 and miR-193a were found to be tumor specifically methylated in patients with NSCLC. We observed a shorter disease-free survival of patients with miR-9-3 methylated lung squamous cell carcinoma (LSCC) than patients with miR-9-3 unmethylated LSCC by multivariate analysis [HR ¼ 3.8; 95% confidence interval (CI), 1.3-11.2, P ¼ 0.017] and a shorter overall survival of patients with miR-9-3 methylated LSCC than patients with miR-9-3 unmethylated LSCC by univariate analysis (P ¼ 0.013).Conclusions: Overall, our results suggest that methylation is an important mechanism for inactivation of certain miRNAs in NSCLCs and that miR-9-3 methylation may serve as a prognostic parameter in patients with LSCC.
ECMO is a valuable tool in lung transplantation providing the potential to bridge patients to transplantation, to replace CPB with at least equal results and to overcome severe postoperative complications. Favourable survival rates can be achieved despite the fact that ECMO is used in the more complex patient population undergoing lung transplantation as well as to overcome already established severe complications.
Ex vivo lung perfusion (EVLP) provides the ability to evaluate donor lungs before transplantation. Yet, limited prospective clinical data exist with regard to its potential to recondition unacceptable donor lungs. This paper summarizes the results of a prospective study of lung transplantation using only initially unacceptable donor lungs, which were improved by EVLP for 2-4 h. From March 2010-June 2011, 13 lungs were evaluated ex vivo. Median donor PaO 2 at FiO 2 1.0/PEEP5 was 216 mmHg (range 133-271). Four lungs, all with trauma history, showed no improvement and were discarded. Nine lungs improved to a ΔPO 2 higher than 350 mmHg. Median PvO 2 at final assessment in these lungs was 466 mmHg (range 434-525). These lungs were transplanted with a median total ischemic time of 577 min (range 486-678). None of the patients developed primary graft dysfunction grades 2 or 3 within 72 h after transplantation. One patient with secondary pulmonary hypertension was left on a planned prolonged extracorporeal membrane oxygenation postoperatively. Median intubation time was 2 days. Thirtyday mortality was 0%. During the observation period, 119 patients received standard lung transplantation with comparable perioperative outcome. EVLP has a significant potential to improve the quality of otherwise unacceptable donor lungs.
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