Project description:Background: Histone deacetylase (HDAC) is strongly associated with epigenetic regulation and carcinogenesis, and its inhibitors induce the differentiation or apoptosis of cancer cells. Valproic acid (VPA) is one of the clinically available HDAC inhibitors. We investigated the anticancer effects of VPA in combination with gemcitabine (GEM) in cholangiocarcinoma cell line, and explored the mechanisms of the anticancer effects using microarray analysis. Methods: A human cholangiocarcinoma cell line (HuCCT1) was used. The anticancer effects of VPA, or gemcitabine (GEM), and the effects of VPA combined with GEM, were studied by cell proliferation assay. The microarray analysis was performed, the genes were picked up using Gene Spring GX11.5, Ingenuity Pathways Analysis (IPA) was performed, and then the gene-expression was determined by RT-PCR. Results: GEM (5nM) and VPA (0.5mM) reduced by 23%, which significantly augmented the anticancer effect of GEM alone or VPA alone (P<0.01). Using the microarray analysis, forty-three genes were identified with the comparison between GEM group and GEM plus VPA combination group. The interactions were shown between genes of the “Cellular Development” relevant to the differentiation of cancer cell using IPA.
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.
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:Background: Histone deacetylase (HDAC) is strongly associated with epigenetic regulation and carcinogenesis, and its inhibitors induce the differentiation or apoptosis of cancer cells. Valproic acid (VPA) is one of the clinically available HDAC inhibitors. We investigated the anticancer effects of VPA in combination with gemcitabine (GEM) in cholangiocarcinoma cell line, and explored the mechanisms of the anticancer effects using microarray analysis. Methods: A human cholangiocarcinoma cell line (HuCCT1) was used. The anticancer effects of VPA, or gemcitabine (GEM), and the effects of VPA combined with GEM, were studied by cell proliferation assay. The microarray analysis was performed, the genes were picked up using Gene Spring GX11.5, Ingenuity Pathways Analysis (IPA) was performed, and then the gene-expression was determined by RT-PCR. Results: GEM (5nM) and VPA (0.5mM) reduced by 23%, which significantly augmented the anticancer effect of GEM alone or VPA alone (P<0.01). Using the microarray analysis, forty-three genes were identified with the comparison between GEM group and GEM plus VPA combination group. The interactions were shown between genes of the “Cellular Development” relevant to the differentiation of cancer cell using IPA. Total RNA was isolated from both the stimulated and unstimulated cells (HuCCT-1) using RNeasy Mini kit (Qiagen, Valencia, CA). Relative purity was examined using an Agilent 2100 Bioanalyzer (Agilent Technologies, Santa Clara, CA, USA). RNA expression was analyzed using GeneChip○R Human Gene 1.0 ST Array (Affymetrix, Santa Clara, CA, USA), containing 28,869 oligonucleotide probes for known and unknown genes. First standard cDNA was synthesized from 300 ng of total RNA by using GeneChip○R Whole Transcript (WT) cDNA Synthesis and Amplification Kit (Affymetrix) according to the manufacturer’s instructions. 10 μg of cRNA were input into the second-cycle cDNA reaction. cDNA was fragmented and end-labeled with the GeneChip○R WT Terminal Labeling Kit (Affymetrix). Approximately 5.5μg of fragmented and labeled DNA target was hybridized to the Affymetrix GeneChip○R Human Gene 1.0 ST Array at 45°C for 17h on a GeneChip○R Hybridization Oven 640 (Affymetrix) according to the manufacturer’s recommendation. Hybridized arrays were washed and stained on a GeneChip○R Fluidics Station 450 and scanned on a GeneChip○R Scanner 3000 7G (Affymetrix), and then generated CEL files for each array. The microarray data was normalized by GeneSpring GX 11.5 software (Agilent). The cut-off value was set at 0.5 to 2.0 for the ratio (more than 2.0: up-regulation, 0.5-2.0: no change, less than 0.5: down-regulation). Gene Ontology (GO) was analyzed using GeneSpring GX 11.5 software (Agilent), and p-value < 0.05 was used for significance. Then we used Ingenuity Pathway Analysis (IPA) 8.7 (http://www.ingenuity.com) to determine the functional pathways associated with the set of differentially expressed genes between genotypes. IPA utilizes the knowledge in the literature about biological interactions among genes and proteins.
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.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes