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: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:Time series of the prostate cancer cell line LNCaP, treated for 2, 4, 6 and 8 hours with the synthetic androgen R1881. As control, the cells were cultured for 2, 4, 6 and 8 hours in the presence of the same concentration of solvent (ethanol). With this short treatment time, we aimed to identify mainly direct targets of the androgen receptor. LNCaP has a very low growth rate in steroid stripped medium and resumes growth on addition of androgens. Keywords: Time course
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: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. Two-condition experiment, KP MSCs vs. 3A6 MSCs.
Project description:The catalytic subunit of the human telomerase (hTERT) is activated during tumorigenesis in many cancers including prostate cancer (PCa). Androgens mediate their effect through the androgen receptor (AR), a key factor controlling PCa growth. hTERT expression is known to be regulated by androgens, however contrarily observed to be inhibited or activated. Here, we reveal that androgens repress or activate hTERT expression in a concentration-dependent manner. Low physiological androgen levels activate while supraphysiological androgen levels (SAL) repress hTERT expression. We confirmed SAL-mediated gene repression of hTERT in native human PCa samples derived from patients treated ex vivo as well as in cancer spheroids derived from androgen-dependent and castration resistant PCa (CRPC) cells. Interestingly, based on chromatin immunoprecipitation (ChIP) data both a positive androgen response element (pARE) at -4kb distal and a negative response element (nARE) at the proximal -0.1kb promoter region were identified. Focusing on the nARE it was narrowed down to -121 to -58 bp in the core promoter region. ChIP experiments confirmed an androgen-dependent recruitment of AR and the tumor suppressors inhibitor of growth 1 and 2 (ING1 and ING2), recently identified as AR co-repressors. Mechanistically, the knockdown of either ING1 or ING2 reduced androgen-mediated repression of hTERT indicating that ING1 and ING2 mediate AR-regulated transrepression on the hTERT expression. Thus, our data suggest a dual, biphasic function of AR to control hTERT expression by transactivation and transrepression. The inhibition of hTERT by androgens by a nARE located in the proximal promoter region is mediated at least in part by the AR co-repressors ING1 and ING2.
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.