Project description:Bone is the most common site of breast cancer metastasis, and this type of metastasis is a main cause of morbidity. Because breast cancer is a heterogeneous disease, the interactions between the cancer cells and the skeletal host cells, such as osteoblasts, might be diverse. Thus far, these tumor-osteoblast interactions have not yet been well characterized using a genomic approach. We hypothesized that gene expression signatures induced by tumor-osteoblast interactions might be of clinical relevance. To examine these gene expression signatures, we established an ex vivo co-culture model with benign human cells and a panel of 5 malignant breast epithelial cells in combination with primary human osteoblasts and determined associated gene expression changes using cDNA microarrays. This SuperSeries is composed of the following subset Series: GSE29030: Normal human osteoblasts and HMEC mono and coculture GSE29031: Normal human osteoblasts and Hs578t mono and coculture GSE29032: Normal human osteoblasts and MCF7 mono and coculture GSE29033: Normal human osteoblasts and MDA-MB-231 mono and coculture GSE29034: Normal human osteoblasts and SKBR3 mono and coculture GSE29035: Normal human osteoblasts and T47D mono and coculture Refer to individual Series
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.