Transcription profiling of human bone tumours to evaluate four commercial high-resolution oligonucleotide microarray platforms.
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ABSTRACT: Evaluation of four commercial high-resolution oligonucleotide microarray platforms, Affymetrix Genome-Wide Human SNP Array 6.0, Agilent Human Genome CGH 244A, Illumina HumanExon510s-duo and Nimblegen HG18 CGH 385k WG tiling v1.0, for genomic profiling of bone tumours.
Project description:Osteosarcomas are the most common primary malignant tumours of bone, and almost all conventional osteosarcomas are high-grade tumours showing complex genomic aberrations. We have integrated genome-wide genetic and epigenetic profiles from the EuroBoNeT panel of 19 human osteosarcoma cell lines based on microarray technologies. The cell lines showed complex patterns of DNA copy number changes, where copy number gains were significantly associated with gene-rich regions of the genome and losses with gene-poor areas. Integration of the datasets showed that the mRNA levels were regulated by either alterations in DNA copy number or DNA methylation. Using a recurrence threshold of 6/19 (> 30 %) cell lines, 348 genes were identified as having alterations of two data types (gain or hypo-methylation/over-expression, loss or hyper-methylation/under-expression). These genes are involved in embryonic skeletal system development and morphogenesis, as well as remodelling of extracellular matrix. Several genes were hyper-methylated and under-expressed compared to normal osteoblasts, and expression could be reactivated by demethylation using 5-Aza-2M-bM-^@M-^Y-deoxycytidine treatment for all four genes tested. Globally, there was as expected a significant positive association between gain and over-expression, loss and under-expression as well as hyper-methylation and under-expression, but gain was also associated with hyper-methylation and under-expression, suggesting that hyper-methylation may oppose the effects of increased copy number for some genes. Integrative analysis of genome-wide genetic and epigenetic alterations identified mechanistic dependencies and relationships between DNA copy number and DNA methylation in terms of regulating mRNA expression levels in osteosarcomas, contributing to better understanding of osteosarcoma biology. Comparison of DNA methylation patterns in 19 osteosarcoma cell lines and 6 normal samples (osteoblasts and bones)
Project description:Osteosarcomas are the most common primary malignant tumours of bone, and almost all conventional osteosarcomas are high-grade tumours showing complex genomic aberrations. We have integrated genome-wide genetic and epigenetic profiles from the EuroBoNeT panel of 19 human osteosarcoma cell lines based on microarray technologies. The cell lines showed complex patterns of DNA copy number changes, where copy number gains were significantly associated with gene-rich regions of the genome and losses with gene-poor areas. Integration of the datasets showed that the mRNA levels were regulated by either alterations in DNA copy number or DNA methylation. Using a recurrence threshold of 6/19 (> 30 %) cell lines, 348 genes were identified as having alterations of two data types (gain or hypo-methylation/over-expression, loss or hyper-methylation/under-expression). These genes are involved in embryonic skeletal system development and morphogenesis, as well as remodelling of extracellular matrix. Several genes were hyper-methylated and under-expressed compared to normal osteoblasts, and expression could be reactivated by demethylation using 5-Aza-2M-bM-^@M-^Y-deoxycytidine treatment for all four genes tested. Globally, there was as expected a significant positive association between gain and over-expression, loss and under-expression as well as hyper-methylation and under-expression, but gain was also associated with hyper-methylation and under-expression, suggesting that hyper-methylation may oppose the effects of increased copy number for some genes. Integrative analysis of genome-wide genetic and epigenetic alterations identified mechanistic dependencies and relationships between DNA copy number and DNA methylation in terms of regulating mRNA expression levels in osteosarcomas, contributing to better understanding of osteosarcoma biology. Comparison of DNA copy number changes in 19 osteosarcoma cell lines
Project description:Osteosarcomas are the most common primary malignant tumours of bone, and almost all conventional osteosarcomas are high-grade tumours showing complex genomic aberrations. We have integrated genome-wide genetic and epigenetic profiles from the EuroBoNeT panel of 19 human osteosarcoma cell lines based on microarray technologies. The cell lines showed complex patterns of DNA copy number changes, where copy number gains were significantly associated with gene-rich regions of the genome and losses with gene-poor areas. Integration of the datasets showed that the mRNA levels were regulated by either alterations in DNA copy number or DNA methylation. Using a recurrence threshold of 6/19 (> 30 %) cell lines, 348 genes were identified as having alterations of two data types (gain or hypo-methylation/over-expression, loss or hyper-methylation/under-expression). These genes are involved in embryonic skeletal system development and morphogenesis, as well as remodelling of extracellular matrix. Several genes were hyper-methylated and under-expressed compared to normal osteoblasts, and expression could be reactivated by demethylation using 5-Aza-2M-bM-^@M-^Y-deoxycytidine treatment for all four genes tested. Globally, there was as expected a significant positive association between gain and over-expression, loss and under-expression as well as hyper-methylation and under-expression, but gain was also associated with hyper-methylation and under-expression, suggesting that hyper-methylation may oppose the effects of increased copy number for some genes. Integrative analysis of genome-wide genetic and epigenetic alterations identified mechanistic dependencies and relationships between DNA copy number and DNA methylation in terms of regulating mRNA expression levels in osteosarcomas, contributing to better understanding of osteosarcoma biology. Comparison of gene expression patterns in 19 osteosarcoma cell lines and 6 normal samples (osteoblasts and bones)
Project description:Let-7 microRNAs (miRNAs) are a family of highly conserved well-established promoters of terminal differentiation that are expressed in all healthy adult tissues and frequently repressed in cancer cells. The tumour suppressive role of let-7 in a variety of cancers in vitro and in vivo has been widely documented and prompted these miRNAs to be candidate genes for miRNA replacement therapy. Reprogrammed metabolism, recently identified as a new hallmark of cancer, contributes to cancer cell growth, proliferation, invasiveness and drug resistance. In this study we identified a new metabolic role of let-7a in triple-negative breast cancer and metastatic melanoma cell lines. We show that let-7a down-regulates key anabolic enzymes, promotes oxidative phosphorylation and mitochondrial ROS formation accompanied by the up-regulation of the oxidative stress responsive genes. To assess if we could exploit these increased ROS levels for therapeutic purposes, we combined let-7a transfection with the antitumor drug doxorubicin. In both cancer types we observed a stronger response to the doxorubicin treatment in let-7a transfected cells. Pre-treatment with an antioxidant N-acetyl cysteine totally abolished this difference, indicating that the increased doxorubicin sensitivity of let-7a cells depends on the redox pathway. We demonstrated that let-7a plays a prominent role in regulating energy metabolism in cancer cells. We propose that a benefit from let-7 miRNA replacement therapy could come not only from the repression of oncogenic pathways targeted directly by let-7, but also by increased sensitivity to chemotherapeutic agents through indirect metabolic changes caused by let-7. Investigation of let-7a metabolic role in breast cancer and melanoma cells.
Project description:The distinction between lymphatic and blood vessels is biologically fundamental. Two immortalized cell lines, which have been widely used as models for endothelial cells of blood vascular origin, are the human microvascular endothelial cell line-1 (HMEC-1) and the telomerase-immortalized microvascular endothelial cell line (TIME). However, analysis of protein expression by flow cytometry revealed expression of lymphatic markers on these cell lines. Furthermore, functional in vitro leukocyte transmigration assays demonstrated deficiencies in several steps of the leukocyte extravasation cascade. Hence we performed this microarray analysis of the gene expression in HMEC-1 and TIME. We then compare the expression profiles to those of published blood- and lymphatic endothelial cells. Analysis of the gene expression profile of the immortalized human endothelial cell lines HMEC-1 and TIME to be compared to published primary blood- and lymphatic endothelial cells (see supplementary file linked below).
Project description:The similarity of Lyme borreliosis to other diseases and the complex pathogenesis cause diagnostic and therapeutic difficulties. Changes at the cellular and molecular level after Borrelia sp. infection remain still poorly understood. Therefore, the present study focused on the gene expression in human dermal fibroblasts in differentiation of infection with Borrelia garinii, Borrelia afzelii and Borrelia burgdorferi sensu stricto spirochetes. For microarray analysis 10 samples were used: 3 control samples - K, 2 samples of NHDF cells infected with Borrelia garinii - G, 2 samples of NHDF cells infected with Borrelia afzelii - A and 3 samples of NHDF cells infected with Borrelia burgdorferi sensu stricto - SS.
Project description:The Fe(II)- and 2-oxoglutarate (2OG)-dependent dioxygenase AlkB from E. coli is a demethylase which repairs alkyl lesions in DNA, as well as RNA, through a direct reversal mechanism. Humans possess nine AlkB homologues (ALKBH1-8 and FTO). ALKBH2 and ALKBH3 display demethylase activities corresponding to that of AlkB, and both ALKBH8 and FTO are RNA modification enzymes. The biochemical functions of the rest of the homologues are still unknown. To increase our knowledge on the functions of ALKBH4 and ALKBH7 we have here performed yeast two-hybrid screens to identify interaction partners of the two proteins. While no high-confidence hits were detected in the case of ALKBH7, several proteins associated with chromatin and/or involved in transcription were found to interact with ALKBH4. For all interaction partners, the regions mediating binding to ALKBH4 comprised domains previously reported to be involved in interaction with DNA or chromatin. Furthermore, some of these partners showed nuclear co-localization with ALKBH4. However, the global gene expression pattern was only marginally altered upon ALKBH4 over-expression, and larger effects were observed in the case of ALKBH7. Although the molecular function of both proteins remains to be revealed, our findings suggest a role for ALKBH4 in regulation of gene expression or chromatin state and support the previous association of ALKBH7 with spermatogenesis. Comparison of DNA methylation patterns in cells over expressing ALKBH4 and ALKBH7
Project description:Human VECs are categorized into two groups regarding their effects on the proliferation of vascular smooth muscle cells (VSMCs):type-I, pro-proliferative VECs and type-II anti-proliferative VECs. The effects of VECs on VSMC proliferation were quantitatively assessed according to the following method: human aortic smooth muscle cells, which were stained by PKH-26 in advance, were cultured on the layer of CFSE-stained VECs, and VSMC proliferation were evaluated after four days by flow cytometry analyses using ModFit LTM-bM-^DM-" software (Verity Software House Inc., Topsham, ME). Commercially available primary human VECs including HUVEC, HAEC and HMVEC as well as the majority of endothelial progenitor cell (EPC)-derived VECs (EPCdECs), whether EPCs were obtained from adult or fetal tissues, enhanced VSMC proliferation, showing type-I phenotype. EPCdECs of minor donors including EPC1dEC suppressed VSMC proliferation, showing type-II phenotype. However, type-II VECs turned into type-I VECs after a few rounds of subcultures. Comparative analyses on gene expression profiles between type-I VECs and type-II VECs revealed that regulator of G-protein signaling 5 (RGS5) was the only gene that showed the discriminative expression pattern: high expressions in type-I VECs and low expressions in type-II VECs. Totally six samples of type-I VECs (HUVEC, HAEC, HMVEC, EPC1dEC[P12], UCEPC1dEC, EPC2dEC[P7]) and two samples of type-II VECs (EPC1dEC[P7] and EPC1dEC[P7] purchased at a different time point) were subjected to the analyses.
Project description:EPC-derived VECs (EPCdECs) are categorized into two group according to their effects on the proliferation of vascular smooth muscle cells: type-I pro-proliferative VECs and type-II anti-proliferative VECs. Type-II EPCdECs were converted to type-I VECs by repetitive subcultures. Not only subculture-dependent cellular stresses but also donor differences greatly affect the phenotype determination of VECs. By comparing the gene expression profiles of type-II EPCdEC of the first donor (EPC1dEC) at early passage and those of type-II EPC1dEC at late passage and EPCdEC of the second donor at early passage, characteristic gene expression patterns that discriminate Type-I and type-II EPCdECs will be comprehended. Totally three samples of type-I EPC-derived VECs (EPC1dEC[P12], EPC2dEC[P7]) and type-II EPC-derived VEC (EPC1dEC[P7]) were subjected to the analyses.