Biomedical subjects

Steve Mohr

Publications and source records attributed to Steve Mohr.

4 recordsLinked to original sources

PubMed2004

Cell protection, resistance and invasiveness of two malignant mesotheliomas as assessed by 10K-microarray.

Malignant pleural mesothelioma (MPM) is an aggressive serosal tumor, strongly associated with former exposure to asbestos fibers and for which there is currently no effective treatment available. In human, MPM is characterized by a high local invasiveness, poor prognosis and therapeutic outcomes. In order to assess molecular changes that specify this phenotype, we performed a global gene expression profiling of human MPM. Using a 10,000-element microarray, we analyzed mRNA relative gene expression levels by comparing a mesothelioma cell line to either a pleural cell line or tumor specimens. To analyze these gene expression data, we used various bioinformatics softwares. Hierarchical clustering methods were used to group genes and samples with similar expression in an unsupervised mode. Genes of known function were further sorted by enzyme, function and pathway clusters using a supervised software (IncyteGenomics). Taken together, these data defined a molecular fingerprint of human MPM with more than 700 up- or down-regulated genes related to several traits of the malignant phenotype, specially associated with MPM invasiveness, protection and resistance to anticancer defenses. This portrait is meaningful in disease classification and management, and relevant in finding new specific markers of MPM. These molecular markers should improve the accuracy of mesothelioma diagnosis, prognosis and therapy.

Biomarkers, Tumor↗

PubMed2004

Microdissection, mRNA amplification and microarray: a study of pleural mesothelial and malignant mesothelioma cells.

The studies of molecular alterations in tumor cells with microarrays are often hampered by inherent tissue heterogeneity. The emergence of Laser Capture Microdissection (LCM) allowed us to overcome this challenge since it gives selective access to cancer cells that are isolated from their native tissue environment. In this report, we microdissected mesothelial cells and malignant mesothelioma cells of ex vivo resected specimens using LCM. Amplified RNA from mesothelial and mesothelioma microdissected cells allowed us to measure global gene expression with 10 K-microarrays in four independent experiments. We screened 9850 annotated human genes, 1275 of which have satisfied our data analysis requirements. They included 302 overexpressed genes and 160 downregulated genes in mesothelioma microdissected cells as compared to mesothelial microdissected cells. Among them, the expression levels of eight genes, namely BF, FTL, IGFBP7, RARRES1, RARRES2, RBP1, SAT, and TXN according to HUGO nomenclature, were increased, whereas six: ALOX5AP, CLNS1A, EIF4A2, ELK3, REQ and SYPL, were found to be underexpressed in mesothelioma microdissected cells. The ferritin light polypeptide (FTL) gene overexpression was confirmed by real time quantitative PCR. Our approach allowed a comprehensive in situ examination of mesothelioma and provided an accurate way to find new marker genes that may be useful for diagnosis and treatment of malignant pleural mesothelioma.

Epithelium↗

PubMed2003

From transcriptomics to bibliomics.

BACKGROUND: Current biological investigations tend to operate with genomes, instead of genes as during the last century. It is possible to compare entire genomes, transcriptomes or proteomes, using alphanumeric data corresponding to the differential expression levels of thousands of genes. What remains difficult is to link array results to factual or bibliographical data and retrieve information that is highly structured and - in Shannon's sense - rare. MATERIAL/METHODS: We have developed a tool, Documentation and Information LIBrary (DILIB), that enables us to retrieve, organize and analyze huge amounts of data available on the Internet and related to microarray experiments. DILIB can link hundreds of differentially expressed genes - through their Single Identifier or GenBank accession number - to hundreds of Medline records, and can retrieve, analyze, and compare automatically thousands of non-trivial descriptors related to gene clusters. RESULTS: As exemplified with frequency comparison of MEdical Subject Headings and Registry Number descriptors, we reanalyzed the involvement of 'integrin', 'interleukin' and 'CD Antigens' in mesotheliomas. Thus, DILIB allowed us to: (i). associate literature to expressed genes, (ii). link functional transcriptomes in various experiments, (iii). associate specific descriptors to experiments, (iv). define new research areas, and eventually (v). find new functions for co-expressed genes. CONCLUSIONS: We propose a new concept, 'bibliomics', representing a subset of high quality and rare information, retrieved and organized by systematic literature-searching tools from existing databases, and related to a subset of genes functioning together in '-omic' sciences.

Databases, Genetic↗

PubMed2002

Microarrays as cancer keys: an array of possibilities.

Malignant transformation results from accumulation of genetic and epigenetic events. Functional studies of cancer will be crucial to our understanding of its complexity and polymorphism. There is no doubt that emerging genomic and proteomic technologies will facilitate such investigations. Microarray technology is a new and efficient approach to extract data of biomedical relevance for a wide range of applications. In cancer research, it will provide high-throughput and valuable insights into differences in an individual's tumor as compared with constitutional DNA, mRNA expression, and protein expression and activity. Across individuals, comparisons could provide tissue-specific disease signatures that provide diagnosis based on hundreds of informative genes. The resulting product should be a wealth of tumor-associated and tumor-specific biomarkers, which may help in cancer etiology, diagnosis, and therapy and ultimately lead to "molecular nosology" of cancers. This review highlights the recent developments in microarray technologies in cancer research, focuses on the results obtained so far, and describes the eventual use of microarray technology for clinical applications.

Animals↗