Malignant pleural mesothelioma (MPM) is a rare, aggressive, and incurable cancer arising from the mesothelial lining of the lungs with few treatment options. We recently reported loss of function of the nuclear deubiquitinase BRCA associated protein-1 (BAP1), a frequent event in MPM, is associated with sensitivity to tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). As a potential underlying mechanism, here we report that BAP1 negatively regulates the expression of TRAIL receptors: death receptors 4 (DR4) and 5 (DR5). Using tissue microarray (TMAs) of tumour samples from MPM patients, we found a strong inverse correlation between BAP1 and TRAIL receptors. BAP1 knockdown increased DR4 and DR5 expression, whereas overexpression of BAP1 had the opposite effect. Reporter assays confirmed wild-type BAP1, but not catalytically-inactive mutant BAP1, reduced promoter activities of DR4 and DR5, suggesting deubiquinase activity plays an important role in the regulation of gene expression. Co-IP studies demonstrated direct binding of BAP1 and the transcription factor Ying Yang 1 (YY1) and ChIP assays revealed BAP1 and YY1 to be enriched in the promoter regions of DR4 and DR5. Notably, shRNA knockdown of YY1 also increased DR4 and DR5 expression, and sensitivity to TRAIL. These results demonstrate that BAP1 and YY1 together negatively regulate transcriptional activity of TRAIL receptors. BAP1 and YY1 may both therefore be strong therapeutic targets to enhance the efficacy of TRAIL-induced apoptosis.Statement of significanceWe describe how the most-frequently mutated tumour suppressor gene in mesothelioma regulates the response to TNF-related apoptosis-inducing ligand (TRAIL). These findings will accelerate a biomarker-driven cancer therapy.

The bronchiectasis severity index derived from these models was composed of prior hospitalisation (5 points), MRC dyspnoea score (0-3 points), FEV 1 (0-3 points), bacterial colonisation (0-3 points) Age (0-6 points) BMI <18.5 (2 points) Exacerbation frequency (0-2 points) and radiological extent (1 point). The AUC for mortality was 0.80 (0.74-0.86) and the AUC for hospitalisation was 0.88 (0.84-0.91). There was a clear difference in exacerbation frequency and quality of life using the St. Georges Respiratory Questionnaire between patients classified as low, intermediate and high risk by the score (p < 0.0001 for all comparisons).In the validation cohorts, the AUC for mortality ranged from 0.81-0.84 and for hospitalisation was AUC 0.80-0.88. Conclusions The bronchiectasis severity index identifies patients at risk of future mortality, hospital admissions and exacerbations. Background Primary ciliary dyskinesia (PCD) is an inherited disease related to ciliary dysfunction, with heterogeneity in clinical presentation, prognosis and ciliary ultrastructure. Our study aimed to comprehensively characterise a large cohort with respect to ciliary ultrastructure, beat frequency, sputum microbiology, mortality and lung function decline. Method A cohort of 100 adult PCD patients was identified at a tertiary respiratory centre. A retrospective analysis of clinical age at presentation and diagnosis alongside ciliary ultrastructure, nasal nitric oxide, beat frequency, sputum microbiology, lung function at diagnosis and follow-up and mortality were recorded. Non-parametric multi-parameter analysis of variance and Spearman rank correlation statistical analysis was performed to identify significant associations with decline in lung function (FEV1%/year). Median duration of follow-up was 7.5years (range 2-30years). Results Overall mortality was 4% (median age of death 55years). 12% of patients had a central pair/transposition defect, 37% missing outer dynein arms, 15% missing inner dynein arms, 28% no arms, and 3% had normal ultrastructure. There was no significant correlation between ciliary ultrastructure, beat frequency (range 0-13.9Hz) and nasal nitric oxide with clinical age at presentation (range 1-26 years) and diagnosis (range 1-72 years) or lung function at presentation and decline with followup. There was additionally no significant association between sputum isolation including Pseudomonas aeruginosa with lung function decline. 44% of patients had Pseudomonas aeruginosa chronic infection. The incidence of NTM colonisation was low (4%). Aspergillus species colonisation was additionally low (5%). The average lung function decline in the cohort was 1.45% FEV1/year. Conclusions Comprehensive characterisation of an adult PCD cohort with ciliary ultrastructure, light microscopy, clinical presentation and follow-up data shows a relatively favourable outcome with optimum care. Ciliary ultrastructure, beat frequency and nasal nitric oxide does not predict prognosis. Contrary to parallel diagnoses such as cystic fibrosis and adult...

Introduction Malignant pleural mesothelioma (MPM) is a highly aggressive, incurable, chemoresistant tumour. Recent studies have shown that Mesenchymal stem cells (MSC) can home to and incorporate into the tumour stroma. Their tumour tropism can be used to deliver Tumour necrosis factor related apoptosis inducing ligand (TRAIL), a transmembrane protein that selectively induces apoptosis in transformed cells. However, not all tumours are sensitive to TRAIL. TRAIL works through triggering the extrinsic apoptotic pathway while conventional chemotherapeutic agents act by triggering the intrinsic apoptotic pathway. We hypothesised the crosstalk between these two pathways could be exploited by combining chemotherapy and MSC-TRAIL in MPM tumour cell lines. Methods MSC were engineered to express TRAIL using a lentiviral plasmid vector. A Tetracycline (Tet)-inducible system was used as a backbone to control the expression of TRAIL. Apoptosis induced by recombinant TRAIL, MSC-TRAIL in MPM cell lines on combination with Vorinostat, a chemotherapeutic agent, was measured by Annexin-V/DAPI based flow cytometry. Results The combination of recombinant TRAIL and Vorinostat act synergistically to induce apoptosis in MPM cell lines. Recombinant TRAIL and Vorinostat, as monotherapies induce 7.17% and 51.35% apoptosis in an MPM cell line JU77 respectively. In CRL2081 and ONE58 cell lines, recombinant TRAIL induces 56.75% and 13.41% apoptosis while Vorinostat leads to 78.95% and 43.97% apoptosis respectively. The combination of recombinant TRAIL and Vorinostat shows an increased amount of apoptosis in JU77, CRL2081 and ONE58 cell lines at 80.77%, 96.6% and 77.27% respectively (Table 1). Similar synergistic affect was observed when TRAIL expressing MSCs were co-cultured with Vorinostat treated MPM cell lines. MSC-TRAIL induced apoptosis in JU77 (48.73%), CRL2081 (57.63%) and ONE58(53.8%). Combined treatment of Vorinostat and MSC-TRAIL significantly increased apoptosis to 77.7% in JU77, 90.93% in CRL2081 and 77.8% in ONE58 cells (Table 1). Conclusion The combination of Vorinostat and recombinant TRAIL acts synergistically to induce apoptosis in malignant plural mesothelioma cells. Similar affect is observed with the combination of MSC-TRAIL and Vorinostat. This study indicates that Mesenchymal stem cells can be used as vectors for delivery of TRAIL and upon combination with Vorinostat, could be a potential therapy for malignant pleural mesothelioma. S128 REDUCTION OF LUNG METASTASIS BY ENGINEERED MESENCHYMAL STEM CELLS EXPRESSING SECRETED SOLUBLE TRAILZQY Yuan, KK Kolluri; University College London, London, UK 10. 1136/thoraxjnl-2013-204457.135 Bone marrow-derived mesenchymal stem cells (MSC) are promising tools for cancer therapy because they are able to home to and incorporate within tumour tissue. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a pro-apoptotic protein that induces selective apoptosis of tumour cells, while sparing normal cells. Therefore it is expected that MSCs engineered to produce TRAIL wou...

clustering with ability to identify upregulation of cancer specific genes in malignant relative to benign nodes (notably EGFR, HGFR/ c-met and HER2 were among genes most upregulated). Conclusion We demonstrate the feasibility of RNA extraction and GEP on EBUS-derived lymph node cytological aspirates and show differences in gene expression profiles between benign and tumourinfiltrated lymph node mRNA. Further studies on larger patient cohorts are necessary to identify expression profiles that can robustly differentiate benign from malignant lymph nodes in NSCLC. Human lung cancers including squamous cell carcinoma (SCC) are a leading cause of death, and while evidence suggests that basal stem cells drive SCC initiation and progression, the mechanisms regulating these processes remain unknown. In this study we show that bcatenin signalling regulates basal stem cell fate and subsequent SCC progression. In a cohort of preinvasive SCCs we established that elevated basal stem cell b-catenin signalling is positively associated with increased disease severity, epithelial proliferation, and reduced intercellular adhesiveness. We demonstrate that transgene-mediated b-catenin inhibition within keratin 14-expressing basal stem cells delayed normal airway repair while basal cell-specific b-catenin activation increased cell proliferation, directed differentiation, and promoted an epithelial-to-mesenchymal transition (EMT) that included increased Snail transcription and reduced E-cadherin-mediated adhesiveness. These effects were recapitulated in normal human bronchial epithelial cells in vitro following both pharmacological bcatenin activation and E-cadherin inhibition, and mirrored our findings in preinvasive SCCs. Overall this data shows that airway stem cell b-catenin modulates cell adhesiveness to determine cell fate and its mis-expression is a key step in the development of human lung cancer. S58 BETA-CATENIN DETERMINES TRACHEAL CELL FATE AND SQUAMOUS LUNG CANCER PROGRESSION BY MODULATING INTERCELLULAR ADHESIVENESS