Project description:The aim was to identify pathways and genes that are transcriptionally deregulated in osteosarcoma due to changes in CpG island DNA methylation. In order to identify candidates, we compared low passage cell cultures derived from a mouse model of osteosarcoma to mature osteoblasts derived by in vitro differentiation of the mouse bone marrow stromal cell line, Kusa4b10. Under cell culture osteoblastic differentiating conditions, Kusa4b10 cells acquire a mature osteoblastic phenotype (21 days). A potential role for DNA methylation in directing gene expression changes was established by integrating gene expression data with genome wide DNA methylation maps generated by methyl-DNA binding domain capture and NimbleGen promoter arrays (MBDCap-Chip). 3 cell lines derived from primary tumors from p53 Rb Osterix-Cre:lox OS model, 3 Osteoblasts (differentiated Kusa4b10 cells (21 days under osteoblastic differentiation conditions)
Project description:Therapeutic targeting of the Wnt pathway is of high clinical interest for treating bone loss disorders such as osteoporosis. These therapies inhibit the action of negative regulators of osteoblastic Wnt signaling. The observation that Wnt inhibitory factor 1 (WNT1) was epigenetic silencing in osteosarcoma (OS) raised concerns for such a treatment approach. In this study, genome-wide methylation profiling of OS derived from mouse models demonstrated Wif1 silencing in OS is not driven by DNA methylation. Treatment of mouse and human OS cells with methylation and HDAC inhibitors showed Wif1 was unresponsive to methylation inhibition but responded robustly to HDAC inhibition. Consistent with an HDAC dependent mechanism of silencing, the Wif1 locus in OS was characterized by low levels of acetylation and a bivalent H3K4/H3K27 trimethylation state. Wif1 expression marked late stages of normal osteoblast development and stratified OS tumours based on differentiation stage across species. Culture of human and mouse OS cells under differentiation inductive conditions increased expression of Wif1 in parallel with known osteoblast differentiation markers. Together these results demonstrate that Wif1 is not targeted for silencing by DNA methylation in OS. The reduced expression of Wif1 in OS cells is in context with their stage in differentiation. 3 cell lines derived from primary tumors from p53 Rb Osterix-Cre:lox OS model, 3 Osteoblasts (differentiated Kusa4b10 cells (21 days under osteoblastic differentiation conditions)
Project description:Purpose: We have used microarrays to identify gene expression profiles that distinguish mouse OS cells from normal pre-osteoblast cells and mature osteoblast cells. Methods: Transcriptional profiles of three cell lines derived from tumors from Osx-Cre p53fl/fl Rbfl/fl (fibroblastic OS) mouse model, and from pre-osteoblast cells (Kusa4b10 mouse bone marrow stromal cell line) and osteoblast cells (derived by in vitro differentiation of the Kusab410 mouse bone marrow stromal cell line) were generated by microarray analysis, each in triplicate, using Affymetrix mouse Gene1.0ST arrays. Transcriptional profiles were analyzed in cell lines derived from tumors from a genetically engineered mouse model of human osteosarcoma (Osx-Cre p53fl/fl Rbfl/fl) and osteoblast cells derived from the Kusa4b10 mouse bone marrow stromal cell line, in the undifferentiated state (pre-osteoblasts) and differentiated state (osteoblasts).
Project description:Expression analysis of OS tumors with shRNA knockdown of PTHR1 mouse OS 80 (a Cre:lox OS cell line from Boston) was tagged with firefly luciferase expression construct. They were then infected with either control (renilla luciferase shRNA) or an shRNA that effective knocks-down PTHR1 (PTHR1.358; para-thyroid hormone receptor). The cells were injected with matrigel onto the back flank of Balb/c nu/nu mice and left to grow for 1 month with weekly monitoring of tumour size by in vivo luciferase assay. At 4 weeks the tumours were removed and trizol stored. Whole tumour was ground up and set form micro-array. 6 tumors with shRNA PTHR1 knockdown ; 6 tumors with shRNA control (renilla luciferase shRNA) knockdown
Project description:Erythroid progenitors purified from EpoRCreR26eYFPADAR1fl/- and EpoRCreR26eYFPADAR1fl/+ control mice were compared for global gene array profiles Each sample was purified from one mouse
Project description:Expression analysis from two genetically engineered mouse models of osteosarcoma determine the expression profile of mouse osteosarcoma Human osteosarcoma (OS) is comprised of three different subtypes: fibroblastic, chondroblastic and osteoblastic. We previously generated a mouse model of fibroblastic OS by conditional deletion of p53 and Rb in osteoblasts. Here we report an accurate mouse model of the osteoblastic subtype using shRNA-based suppression of p53. Like human OS, tumors frequently present in the long bones and preferentially disseminate to the lungs; features less consistently modeled using Cre:lox approaches. Our approach allowed direct comparison of the in vivo consequences of targeting the same genetic drivers using different technology. This demonstrated that the effects of Cre:lox and shRNA mediated knock-down are qualitatively different, at least in the context of osteosarcoma. Through the use of complementary genetic modification strategies we have established a model of a distinct clinical subtype of OS that was not previously represented and more fully recapitulated the clinical spectrum of this human tumor. 4 primary tumors from Cre:lox OS model; 4 primary tumors from shRNA OS model.
Project description:The goal of this study was to determine genes affected by depletion of KDM4A in HEK293T cells This data was used in Van Rechem et. al. Cancer Discovery 2014 to demonstrate that depletion of KDM4A did not alter expression of genese associated with translation. The experiment uses two different shRNA constructs; shKDM4A.2 in a pSuper backbone and shKDM4A.6 in a pLKO backbone. A corresponding empty vector control was conducted for each backbone. Each shRNA was compared to its own control.
Project description:Full transcriptomes of the Botrytis cinerea wild-type strain B0510 inoculated on mature grapevine berries (Marselan cultivar) at 16h, 24h, 48h, and in vitro were compared to identify B. cinerea genes diffentially expressed during the infection stages. Grapevine berries were inoculated with Botrytis cinerea conidia and samples were taken at 16h, 24h and 48 hours post-inoculation. An additional control sample corresponding to mycelium growing on static liquid minimal medium was included in the experimental design in order to identify genes that would be differentially expressed between in vitro and in planta growth conditions. 3-4 replicates were performed. The 13 total-RNA samples were used for hybridization on NimbleGen 4plex gene expression arrays (20,885 gene models from Botrytis cinerea with three 60-mer probes per gene).
Project description:We identified directly and indirectly regulated target genes utilizing an inducible TEL-AML1 system derived from the murine pro B-cell line BA/F3 and a monoclonal antibody directed against TEL-AML1. By integration of promoter binding identified with ChIP-on-chip, gene expression and protein output through microarray technology and stable labelling of amino acids in cell culture (SILAC), we identified directly and indirectly regulated targets of the TEL-AML1 fusion protein. Bound promoter regions of immunoprecipitated AML1 associated genes were first compared to input material and enrichment was calculated. The same was performed for empty vector control cell lines, also treated with the induction reagent mifepriston. Enriched promoter regions were then compared of the both sets. 3 independent replicates each (6 arrays) were performed.