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H. Pass
Moderator of
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MS24 - Mesothelioma Biology and Biomarkers (ID 41)
- Event: WCLC 2013
- Type: Mini Symposia
- Track: Mesothelioma
- Presentations: 4
- Moderators:B. Robinson, H. Pass
- Coordinates: 10/30/2013, 14:00 - 15:30, Bayside 104, Level 1
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MS24.1 - A Tractable Animal Model of Mesothelioma (ID 574)
14:04 - 14:24 | Author(s): R. Lake
- Abstract
- Presentation
Abstract
We have developed a novel transgenic mouse (MexTAg) where cellular transformation is driven by the SV40 (simian virus 40) large T antigen (TAg). In these mice, TAg is specifically targeted to the mesothelial compartment because it is expressed under the control of a tissue specific promoter. MexTAg mice uniformly develop mesothelioma after exposure to asbestos, with no spontaneous formation of other tumours. The key differences between MexTAg and wild type animals are the higher incidence and the shorter latency of the disease. Survival after diagnosis is not different suggesting that TAg does not drive a more aggressive disease. The model is comparable to human mesothelioma because of the eliciting carcinogen and because the location, pathology, molecular lesions and tumour response to therapy are similar (Robinson et al., 2006; Robinson et al., 2011). It is thought that asbestos fibres drive cellular transformation via the production of reactive oxygen species and the induction of chronic local inflammation. Accordingly, we have begun to test antioxidants and anti-inflammatory drugs as potential cancer prevention agents. We have reported that dietary supplementation with the antioxidants, vitamins A, E and selenium does not affect overall survival nor the time to progression of asbestos-induced mesothelioma in MexTAg mice (Robinson et al., 2012). We have extended our analysis to vitamin D and compared survival of asbestos-exposed MexTAg mice provided with diets supplemented (4500 IU/kg feed) or deficient in vitamin D (cholecalciferol). Survival of supplemented mice was significantly shorter than mice given standard diet (median survival, 29 and 32.5 weeks respectively). Mice deficient in vitamin D developed mesothelioma at the same rate as control mice. We conclude that vitamin D is unlikely to moderate the incidence of disease in asbestos exposed populations or to ameliorate the pathology in patients with established mesothelioma. Mesotheliomas in MexTAg mice respond to cytotoxic chemotherapy. Gemcitabine treatment from week 16 prolonged survival of asbestos-exposed MexTAg mice increasing the median survival from 33 weeks to 48 weeks. Interestingly, latency was not significantly prolonged, but animals survived for longer after the first signs of disease were noted. To understand the importance of the immune system in the pathogenesis of mesothelioma, we crossed MexTAg mice with immune deficient RAG KO mice. Perhaps surprisingly, MexTAg mice with no acquired immunity lived longer with a more indolent disease than their immunocompetent sibs. We compared cell lines derived from mesotheliomas from MexTAg mice and cell lines from wild type mice with human mesothelioma cell lines by expression array. TAg expressing mouse tumours were 90% identical to wild type mouse tumours. The key pathway that was different was cell cycle-associated. Human mesotheliomas commonly have a deletion of the cdkN2 locus, encoding the tumour suppressor genes p16 and p15. While wild type mouse tumours carried a homologous p16 deletion, TAg tumours did not. We hypothesize that TAg expressing mice develop tumours in an accelerated way following asbestos exposure because they are not dependent on deletion of p16 for tumourigenesis. Robinson, C., I. van Bruggen, A. Segal, M. Dunham, A. Sherwood, F. Koentgen, B.W. Robinson, and R.A. Lake. 2006. A novel SV40 TAg transgenic model of asbestos-induced mesothelioma: malignant transformation is dose dependent. Cancer Res 66:10786-10794. Robinson, C., A. Walsh, I. Larma, S. O'Halloran, A.K. Nowak, and R.A. Lake. 2011. MexTAg mice exposed to asbestos develop cancer that faithfully replicates key features of the pathogenesis of human mesothelioma. Eur J Cancer 47:151-161. Robinson, C., S. Woo, A. Walsh, A.K. Nowak, and R.A. Lake. 2012. The antioxidants vitamins A and E and selenium do not reduce the incidence of asbestos-induced disease in a mouse model of mesothelioma. Nutrition and cancer 64:315-322.Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
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MS24.2 - In Vitro Models in Mesothelioma (ID 575)
14:24 - 14:47 | Author(s): V.C. Broaddus, D. Barbone
- Abstract
- Presentation
Abstract
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MS24.3 - Apoptosis and Chemoresistance (ID 576)
14:47 - 15:07 | Author(s): S. Busacca
- Abstract
- Presentation
Abstract not provided
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MS24.4 - New Biomarker Research in Mesothelioma (ID 577)
15:07 - 15:30 | Author(s): J. Creaney
- Abstract
- Presentation
Abstract
Malignant mesothelioma (MM) represents a significant clinical challenge. Not only can this tumour be difficult to diagnose but treatment options are limited. There is a desperate clinical need for biomarkers that can aid the diagnosis of MM, and/or predict survival and measure disease response to treatment. MM diagnosis is challenging as phenotypic differentiation of malignant mesothelial cells from benign reactive ones is notoriously difficult. No immunohistochemical marker(s) can uniformly define the cancer either. Invasive pleural tissue sampling for MM is more frequently negative than in any other cancer type [1]. A reliable diagnostic marker will present a major aid to clinicians. The median survival for the MM population is less than 12 months, however about 5% of patients live for several years and unusually long survivals of over 10 years have also been seen. But no reliable prognostic algorithm exists to predict survival in individual cases – a question of utmost concern for patients and their families. There is no cure for MM. Chemotherapy may improve survival, but only 30 to 40% of patients respond [2]. Thus finding a biomarker that may reflect disease burden and response to therapy, and hence prognosis, will be a significant advance. It has been nearly a decade since mesothelin [3] and MPF [4,5]were reported as candidate biomarkers for MM, both providing similar diagnostic accuracy [6]. A recent meta-analysis of serum mesothelin in the diagnosis of MM determined that having a sensitivity of 32% at a 95% specificity was too low for diagnostic use and highlighted the need for ongoing research for better biomarker(s) [7]. However, studies world-wide on a range of soluble markers including osteopontin, hyaluronic acid, CA125, CA15-3 and others have failed to improve upon diagnostic accuracy. More potential biomarkers such as fibulin-3 and the SOMamer panel have recently been identified [8,9]and the search to discover novel biomarker(s) for this disease using a variety of genomic, proteomic and immunologic approaches continues. For these candidate MM biomarkers to attain their professed clinical potential, independent externally validated studies with large, representative patient cohorts will be required. The next stage will then need studies to determine how to integrate promising markers into clinical diagnostic and/or management algorithms, a process essential to improve outcomes for MM patients. 1 Davies, H. E. et al. Outcome of patients with nonspecific pleuritis/fibrosis on thoracoscopic pleural biopsies. Eur J Cardiothorac Surg 38, 472-477, (2010). 2 Nowak, A. & Bydder, S. Management of malignant pleural mesothelioma: a review. Asia Pacific J clin Oncol (2007). 3 Robinson, B. W. et al. Mesothelin-family proteins and diagnosis of mesothelioma. Lancet 362, 4 Onda, M. et al. Megakaryocyte potentiation factor cleaved from mesothelin precursor is a useful tumor marker in the serum of patients with mesothelioma. Clin Cancer Res 12, 4225-4231 (2006). 5 Shiomi, K. et al. Novel ELISA system for detection of N-ERC/mesothelin in the sera of mesothelioma patients. Cancer Sci 97, 928-932 (2006). 6 Hollevoet, K. et al. Diagnostic performance of soluble mesothelin and megakaryocyte potentiating factor in mesothelioma. Am J Respir Crit Care Med 181, 620-625, (2010). 7 Hollevoet, K. et al. Serum mesothelin for diagnosing malignant pleural mesothelioma: an individual patient data meta-analysis. J Clin Oncol 30, 1541-1549, (2012). 8 Ostroff, R. M. et al. Early detection of malignant pleural mesothelioma in asbestos-exposed individuals with a noninvasive proteomics-based surveillance tool. PLoS One 7, e46091, (2012). 9 Pass, H. I. et al. Fibulin-3 as a blood and effusion biomarker for pleural mesothelioma. N Engl J Med 367, 1417-1427, (2012).Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
Author of
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O09 - General Thoracic Surgery (ID 100)
- Event: WCLC 2013
- Type: Oral Abstract Session
- Track: Surgery
- Presentations: 1
- Moderators:G.E. Darling, W. Weder
- Coordinates: 10/28/2013, 16:15 - 17:45, Parkside Ballroom B, Level 1
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O09.04 - DISCUSSANT (ID 3921)
16:45 - 17:00 | Author(s): H. Pass
- Abstract
- Presentation
Abstract not provided
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P1.01 - Poster Session 1 - Cancer Biology (ID 143)
- Event: WCLC 2013
- Type: Poster Session
- Track: Biology
- Presentations: 1
- Moderators:
- Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
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P1.01-008 - Inhibition of Binding at Exon 4 of Osteopontin Increases Apoptosis and Apoptotic Protein Expression in Non-Small Cell Lung Cancer (ID 2885)
11:08 - 11:22 | Author(s): H. Pass
- Abstract
Background
Osteopontin (OPN) is a ubiquitous extracellular protein associated with a wide range of normal and pathologic functions. It is a central regulator of the malignant phenotype in non-small cell lung cancer (NSCLC) through binding of cell surface receptors, but underlying mechanisms are poorly understood. Among OPN’s critical roles in NSCLC progression, is preventing apoptosis related to oxidative stress by activating alternative survival pathways. While OPN’s central RGD domain is considered important to this function, we hypothesize that exon 4, in the amino terminus, which is present in OPN’s A and B isoforms, but not in the C isoform, is essential to this process. We sought to determine the impact of inibition of binding between NSCLC cells and OPN exon 4 on apoptosis and apoptotic protein expression in NSCLC.Methods
A 16 amino acid peptide mimicking the central sequence of OPN exon 4 and a scrambled sham were constructed. Competitive binding assays had previously determined that the OPN exon 4 peptide binds the NSCLC cell surface and inhibits OPN binding. Two NSCLC cell lines with wt p53, A549 (moderate endogenous OPN) and H460 (high endogenous OPN), were placed in serum-free media with OPN exon 4 peptide or scrambled peptide for 48 hours. Cells were then evaluated by TUNEL assay or harvested, lysed and protein expression measured using Human Apoptosis Array (R&D, Minneapolis, MN).Results
Exon 4 peptide treatment resulted in significant increases in apoptosis in both cell lines (Fig). A similar pattern of change in apoptotic protein expression was seen in both cell lines, with significant increases in Bax, cleaved Caspase-3, CytC, Hsp32, Pon2, Cdnk1, and p53-pS15, p53-pS46, and p53-pS392, while Survivin and Claspin expression were significantly decreased (Fig). Notably no significant change was seen in Bclx, Bcl2, and pro-Caspase 3 expression. Scrambled peptide had no effect on apoptosis or protein expression. Figure 1Conclusion
Inhibition of binding between OPN exon 4 and NSCLC cells significantly increased the rate of apoptosis and expression of proteins which modulate apoptosis associated with oxidative stress, including several key phosphorylated p53 variants. These data implicate OPN exon 4 interactions in NSCLC progression and resistance mechanisms and may explain the importance of OPN’s A and B isoforms as opposed to isoform C in NSCLC pathogenesis.
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P1.06 - Poster Session 1 - Prognostic and Predictive Biomarkers (ID 161)
- Event: WCLC 2013
- Type: Poster Session
- Track: Biology
- Presentations: 1
- Moderators:
- Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
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P1.06-055 - The RON (MST1R)/MSP pathway is a potential therapeutic target in malignant plural mesothelioma (ID 3250)
09:30 - 09:30 | Author(s): H. Pass
- Abstract
Background
Malignant pleural mesothelioma (MPM) is an aggressive inflammatory cancer. Treatment options are limited and drug resistance is common. Thus, there is a need to identify novel therapeutic targets in this disease in order to improve treatment options and survival times. Macrophage stimulating protein (MSP) is the only ligand recognised to bind to the RON receptor (MST1R). RON is a member of the MET proto-oncogene family. The MSP-RON signalling pathway has been implicated in a variety of cellular functions such as macrophage morphogenesis and phagocytosis. De-regulation of this pathway has been linked to tumour progression and metastasis in a number of cancers. We have previously identified RON as frequently activated in MPM and high positivity for RON by IHC was an independent predictor of favourable prognosis.Methods
A panel of mesothelioma cell lines were screened for the expression of MSP and RON at the mRNA (RT-PCR) and protein (Western blot) level. The effect of MSP, IMC-RON8 (a humanised IgG1 monoclonal antibody), LCRF004 (a small molecule inhibitor) and NRWHE (a small peptide) was examined in the H226 cell line using proliferation (BrdU ELISA), apoptosis (Multi-parameter apoptosis assay) and migration assays (xCELLigence). A phospho-kinase proteome profiler array was utilised to detect the downstream signalling pathways activated upon MSP stimulation. The expression of MSP and the macrophage marker, CD-68, was examined by IHC using MPM TMAs. Studies are ongoing to determine the effect of the LCRF004 compound in vivo using a xenograft murine model with the H226 cells.Results
The mRNA and protein levels of RON and MSP were differentially expressed in a panel of MPM cell lines. Treatment with LCRF004 resulted in significantly decreased proliferation and increased apoptosis in the H226 cells. MSP was unable to rescue the cells from the effects of LCRF004. NRWHE and RON8 had little effect on either proliferation or apoptosis. All of the compounds examined inhibited the migration capacity of the H226 cells. The combination of LCRF004 and MSP produced a synergistic effect, showing greater inhibition of migration than either compound alone. However, MSP treatment resulted in the up-regulation of a number of phosphor-kinases including Akt, ERK and the Src family. Currently, a number of proteins identified in the array studies are undergoing validation. Results of an in vivo H226 murine model using the LCRF004 compound will be presented at the meeting.Conclusion
From previous work performed in this laboratory, we have determined that high expression of RON in MPM is an independent predictor of favourable prognosis. IHC was performed on a TMA of MPM patient samples and high expression levels of MSP correlated with better survival. There was no association between CD68 staining and MSP, nor correlation of CD68 expression with survival. Targeting the RTK domain of the RON receptor with a small molecule inhibitor is an effective interventional strategy in MPM. The seemingly counter intuitive results obtained from the MPM TMA studies and the in vitro experimental data, may be RON isoform dependant. Additional studies are ongoing to further delineate the RON-MSP axis in MPM.
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P1.22 - Poster Session 1 - Epidemiology, Etiology (ID 166)
- Event: WCLC 2013
- Type: Poster Session
- Track: Prevention & Epidemiology
- Presentations: 1
- Moderators:
- Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
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P1.22-012 - Continuous exposure to chrysotile asbestos can cause transformation of human mesothelial cells via HMGB1 and TNF-α signaling. (ID 3478)
09:30 - 09:30 | Author(s): H. Pass
- Abstract
Background
Background: Malignant mesothelioma is strongly associated with asbestos exposure. Among asbestos fibers, crocidolite is considered the most and chrysotile the least oncogenic. Chrysotile accounts for >90% of asbestos used worldwide but its capacity to induce malignant mesothelioma is still controversial.Methods
Methods: Human mesothelial cells were exposed to crocidolite or chrysotile for a period of 48hr or 5 weeks, either in the presence of TNF–α or human macrophages in a co-culture system mimicking the process of recruitment and activation of inflammatory cells to sites of fiber deposition, which leads to the carcinogenesis of mesothelioma. Functional studies, as well as whole-genome wide expression profiling were performed to compare the molecular mechanisms and the carcinogenic potential of chrysotile and crocidolite.Results
Results: We found that chrysotile and crocidolite exposures have similar effects on human mesothelial cells. Morphological and molecular alterations suggestive of epithelial-mesenchymal transition, such as E–cadherin down-regulation and β–catenin phosphorylation followed by nuclear translocation, were induced by chrysotile and crocidolite. Gene expression profiling data detected High-Mobility Group Box-1 protein (HMGB1) as a key regulator of the transcriptional alterations induced by both chrysotile and crocidolite. Crocidolite and chrysotile induced differential expression of 57 out of 28,869 genes interrogated by oligo-nucleotide microarrays and 13 were HMGB1 targeted genes. Crocidolite-induced gene alterations were sustained, while chrysotile effects returned to background levels in five weeks. Similarly, HMGB1 release in vivo progressively increased for 10 or more weeks following crocidolite exposure, while returned to background levels eight weeks from chrysotile exposure.Conclusion
Conclusion: Our results show that chrysotile has the capacity to induce, in HM, molecular changes associated to MM development similar to those induced by crocidolite, but these changes are short lasting. The data suggest that HMGB1 and TNF–α are key mediators of these processes for both crocidolite and chrysotile. However a continuous administration of chrysotile was required for inducing sustained HMGB1 levels. These data support the hypothesis that the different bio-persistence of the two asbestos fibers influences their biological activities.
