Project description:Previous reports demonstrate that the α2-integrin (α2) mediates pancreatic ductal adenocarcinoma (PDAC) cell interaction with collagens. We found that untransformed pancreatic ductal epithelial cells and well-differentiated PDAC cells use α2 exclusively to adhere and migrate on collagenI. In contrast, poorly-differentiated PT45P1 and MIAPaCa2 cells demonstrate reduced reliance on, or complete loss of α2, respectively. Further, well-differentiated PDAC lines exhibit reduced in vitro invasion compared to poorly-differentiated lines, and α2-blockade suppressed invasion of well-differentiated lines exclusively. Based on these data and the demonstrated role of α2 in maintaining tissue architecture in other organs, we hypothesized that α2 may actually suppress the malignant phenotype in PDAC. Accordingly, stable ectopic expression of α2 in MIAPaCa2 cells (MP2-α2) retarded in vitro invasion. MP2-α2 cells maintained on collagenI were more invasion-retarded than MP2-α2 cells maintained in standard tissue culture, and demonstrated higher α2β1 expression that was reflected in faster and more complete adhesion/migration on collagenI. Affymetrix gene expression profiling of α2-expressing and mock-transfected cells revealed that kallikrein-related peptidases (KLK)-5, 6 and 7 were specifically upregulated by α2. Accordingly, well-differentiated PDAC lines express KLK-5, 6 and 7 and KLK blockade increased invasion as well as collagenI-migration in KLK-positive lines. Importantly, an α2 cytoplasmic deletion mutant promoted KLK expression and retarded invasion, while an α9α2 chimera retarded invasion less efficiently, and did not impact KLK expression. These data demonstrate for the first time that the α2-ectodomain and KLKâ??s coordinately regulate a less invasive phenotype in PDAC cells. Experiment Overall Design: Affymetrix global gene arrays were used to analyse differences in gene expression patterns in MIAPaCa2 cells stably reexpressing the alpha2 integrin, a cytoplasmic deletion of the alpha2 integrin (dCYTO) or an alpha9 ectodomain and transmembrane domain/alpha2 cytoplasmic domain chimera, versus vector-only mock controls. RNA was harvested from cells passaged identically and maitained under standard tissue culture conditions or on collagenI- or tenascin FNIII-coated plates.. Experiment Overall Design: Genetic manipulation (stable transgene expression)
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:CRISPR-cas9 technology was used to knock out alpha2 integrin in DU145 cells. To create two cell lines that could be compared to each other in an appropriate manner, these cells were transfected either with alpha2 integrin cDNA or empty vector. The objective of the study was to find potential alpha2 integrin regulated genes when the cells were grown as spheroids.
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:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs.
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.
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. One-condition experment, gene expression of 3A6
Project description:As the evolution of miRNA genes has been found to be one of the important factors in formation of the modern type of man, we performed a comparative analysis of the evolution of miRNA genes in two archaic hominines, Homo sapiens neanderthalensis and Homo sapiens denisova, and elucidated the expression of their target mRNAs in bain.A comparative analysis of the genomes of primates, including species in the genus Homo, identified a group of miRNA genes having fixed substitutions with important implications for the evolution of Homo sapiens neanderthalensis and Homo sapiens denisova. The mRNAs targeted by miRNAs with mutations specific for Homo sapiens denisova exhibited enhanced expression during postnatal brain development in modern humans. By contrast, the expression of mRNAs targeted by miRNAs bearing variations specific for Homo sapiens neanderthalensis was shown to be enhanced in prenatal brain development.Our results highlight the importance of changes in miRNA gene sequences in the course of Homo sapiens denisova and Homo sapiens neanderthalensis evolution. The genetic alterations of miRNAs regulating the spatiotemporal expression of multiple genes in the prenatal and postnatal brain may contribute to the progressive evolution of brain function, which is consistent with the observations of fine technical and typological properties of tools and decorative items reported from archaeological Denisovan sites. The data also suggest that differential spatial-temporal regulation of gene products promoted by the subspecies-specific mutations in the miRNA genes might have occurred in the brains of Homo sapiens denisova and Homo sapiens neanderthalensis, potentially contributing to the cultural differences between these two archaic hominines.