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:Gene-expression profiles of liver tissue of cabon tetrachloride (CCl4)-treated mouse and the effect of erlotinib Hepatocellular carcinoma (HCC) is the sixth most common solid tumor worldwide and the third leading cause of cancer-related death. Given the lack of successful treatment options, chemoprevention in high-risk patients has been proposed as an alternative strategy. Mounting evidence supports a role for epidermal growth factor (EGF) during chronic liver disease and hepatocellular transformation. We address the hypothesis that blocking the EGF-EGF receptor (EGFR) pathway may be an effective strategy for inhibiting fibrogenesis and hepatocarcinogenesis. A rat model of diethylnitrosamine (DEN)-induced cirrhosis was used to examine the effects of erlotinib on underlying chronic liver disease and HCC formation. The DEN-induced rat model closely resembles disease progression in humans both pathologically and molecularly. Erlotinib significantly prevented the development of HCC tumor nodules in a dose-dependent fashion. Further, erlotinib inhibited the activation of hepatic stellate cells and prevented fibrogenesis. Erlotinib also reduced hepatotoxicity and improved liver function. Finally, a gene expression signature predictive of poor survival in human cirrhosis patients was reversed in response to erlotinib. Our data demonstrate for the first time that EGFR inhibition prevents liver fibrogenesis. Further, our results suggest that erlotinib is a potentially effective HCC chemoprevention strategy through inhibition of cirrhosis progression which can be monitored at the molecular level.
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 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.