Gene expression profiles in MexTAg transgenic mouse and wild type mouse asbestos-induced mesothelioma
Ontology highlight
ABSTRACT: Malignant mesothelioma is an aggressive tumour arising from the mesothelial cells lining the pleura, peritoneum or pericardium. The principal carcinogen associated with malignant mesothelioma is asbestos . A transgenic mouse model, denoted MexTAg, which encodes the Simian Virus 40 (SV40) large T antigen (TAg) downstream of the mesothelin promoter was developed. Inactivation of the tumour suppressors p53 and RB following binding to TAg results. In this model mesothelioma develops in the mesothelial cell compartment after the mice have been exposed to asbestos. The MexTAg transgenic mouse model of mesothelioma model enables analysis of the molecular events associated with asbestos induced mesothelioma and is utilised here to investigate the molecular dynamics of tumours induced in these mice, using gene expression patterns as a read out.
Project description:Malignant mesothelioma (MM) is an aggressive tumor strongly associated with asbestos exposure. The granuloma capturing crocidolite contribute to mutagenesis, cell death and regenerative activity. To clarify the biological responses of mesothelial cells after crocidolite exposure, we compared the microarray gene expression profiles of no treatment and crocidolite exposure (1 wks) mesothelial cells induced by intraperitoneal injections.
Project description:We hypothesize that the observed differences in incidences of pleural and peritoneal malignant mesothelioma (MM) are the result of differences in the direct response of these cell types to asbestos rather than to differences mediated by the in vivo microenvironment. To test this hypothesis, we characterized cellular responses to asbestos in a controlled environment using high-throughput RNA sequence and other assays. Examination of asbestos-treated versus untreated mesothelial cells from four cell lines representing two tissue types in culture.
Project description:Malignant pleural mesothelioma (MPM), which is associated with occupational asbestos exposure, is a deadly disease with no effective treatments due mainly to its high resistance to anti-cancer drugs. The molecular mechanisms responsible for its chemotherapeutic resistance are complicated and undefined. However, the presence of side population cells (SP cells) in tumors is a well-accepted explanation for their anti-cancer drug resistance. To identify SP cell-specific gene expression signature, microarray technique has been employed. Our data show differential gene expression profiles between SP and non-SP cells of H2714 mesothelioma cells. SP cells over-expressed genes associated with cancer stem cell (CSC) and drug resistance: DUSP6, SPRY2 and IL6, as well as multi-pathways, including the cancer stem cell-associated pathways Notch and c-Kit. Therefore, we believe that targeting CSC-specific genes and pathways in SP cells may hold the key to the discovery of effective treatments for reversing chemotherapeutic resistance to MPM treatment. 4 samples
Project description:Malignant mesothelioma is one of the most aggressive forms of cancer known. Recent studies have shown that carbon nanotubes (CNTs) are biopersistent and induce mesothelioma in animals, but the underlying mechanisms are not known. Here, we investigate the effect of long-term exposure to CNTs on the aggressive behaviors of human pleural mesothelial cells, the primary cellular target of human lung mesothelioma. We show that sub-chronic exposure (4 month) to single- and multi-walled CNTs induced proliferation, migration and invasion of the cells similar to that observed in asbestos-exposed cells. An up-regulation of several key genes known to be important in cell invasion, notably matrix metalloproteinase-2 (MMP-2), was observed in the exposed mesothelial cells as determined by real-time PCR. Western blot and enzyme activity assays confirmed the increased expression and activity of MMP-2. Whole genome expression microarray analysis further indicated the importance of MMP-2 in the invasion gene signaling network of the exposed cells. Knockdown of MMP-2 in CNT and asbestos-exposed cells by shRNA-mediated gene silencing effectively inhibited the aggressive phenotypes. This study provides new evidence for CNT-induced cell invasion and indicates the role of MMP-2 in the process. Whole genome expression profiling was conducted on human immortalized pleural mesothelial cells (MeT5A) following 4 month in vitro sub-chronic exposure to six separate treatments to assess differences in carbon nanotube (CNT) vs. asbestos potential tumorigenesis signaling. Dispersed single wall CNT (D-SWCNT), multi-wall CNT (D-MWCNT), crocidolite asbestos (ASB) and saline (SAL) exposed cells were compared to Survanta® dispersant (DISP) passage control cells. DISP and SAL cells served as control treatments for CNT- and ASB-exposed cells, respectively. Each treatment possessed 3 biological cDNA replicates. One technical replicate was performed per biological sample.
Project description:Human malignant mesothelioma (MM) is an aggressive tumor strongly associated with asbestos exposure. SM patients generally have poorer prognosis compared to EM patients. To identify potential genes accounting for the differential prognosis between these two subtypes, we compared the microarray gene expression profiles of rat SM and EM tissues induced by intraperitoneal injections of 3 types of asbestos (chrysotile,crocidolite and amosite). Carcinogenesis protocol was performed using specific pathogen-free male and female F1 hybrid rats between Fischer344 and Brown-Norway strains. A total of 28 microarrays (Whole Rat Genome Microarray) were used for screening purpose: The 2 arrays were used for knife-scraped peritoneal mesothelial cells, 2 arrays for cultured peritoneal mesothelial cells and 24 arrays for MM samples.
Project description:Introduction: Pleural mesothelioma (PM) is known as one of the most aggressive malignancies among all cancers, despite of usually absent tumor-driver mutations in oncogenes. It develops in a unique inflammatory tumor microenvironment (TME), which has been postulated as major contributor of PM’s highly aggressive nature. Mesothelioma-associated fibroblasts (Meso-CAFs), a main component of the TME have recently been shown to substantially stimulate several aspects of PM aggressiveness and promote the malignant transformation of pleural mesothelial cells. However, respective cell models for TME research in PM are still very limited. The most commonly used pleural mesothelial cell line Met5A has been established decades ago and patient-derived Meso-CAFs have just recently been characterized for the first time. The aim of the current study was to generate and characterize pleural mesothelial and Meso-CAF cell models with an extended life span that closely resemble the primary cells isolated from human tissue. Methods: Pleural mesothelial cells and Meso-CAFs were isolated from human tissue of pneumothorax and PM patients, respectively. Retroviral transduction was used to induce stable expression of human telomerase reverse transcriptase (hTERT) and enhanced green fluorescent protein (EGFP) in the primary cells. The established cell models were evaluated by measuring their doubling times, gene expression and protein activity levels of hTERT, as well as the absolute lengths of telomeres. The transduced cells were compared to their primary counterparts on the protein level using proteome analysis and the impact of their conditioned media (CM) on tumor cell growth was investigated by videomicroscopy. Results: All transduced derivatives exhibit elevated hTERT gene expression and protein activity, increased hTERT protein amounts in the nucleus, and moderately higher absolute telomere lengths compared to their parental primary cells. The transduction with hTERT did not elicit marked changes in the morphology of the cells, as well as in their proteomes and secretomes. The CM of primary and hTERT-transduced Meso-CAFs comparably stimulated PM cell growth, while medium conditioned by normal pleural mesothelial cells including their hTERT-transduced derivatives was not able to induce a growth stimulating effect. Conclusion: The hTERT-transduced cells closely resemble their primary counterparts, while retaining telomerase activity, thus preventing replicative senescence. The new cell models provide valuable tools for the investigation of cellular interactions cellular interactions within the TME of PM and thus may help to identify novel biomarkers for early diagnosis and to develop new therapeutic strategies.
Project description:Malignant mesothelioma (MM) is an asbestos-related malignancy. Discrimination between MM and reactive mesothelial hyperplasia (RM) is often difficult. MM cells have a broad histological spectrum, and consist mainly of epithelioid, sarcomatoid, and biphasic cell types. The prognosis of MM is generally poor, but better prognosis has been reported with the epithelioid type of MM than the non-epithelioid type. We applied a genome-wide analysis to the identification of new markers that may aid in differentiating the epithelioid type of MM from other histological types and from RM cells. Array-based comparative genomic hybridization analysis was performed on malignant mesothelioma (MM) primary cell cultures, reactive mesothelial hyperplasia (RM) primary cell cultures; early passage of in vitro primary cell cultures to minimize acquisition of additional genomic changes. If available, matched peripheral blood was applied to analysis.