Project description:Cen3tel cells, obtained by telomerase immortalization of human fibroblasts, gradually underwent neoplastic transformation and became metastatic in immunocompromised mice. Neoplastic transformation was associated with a change in cell morphology (from fibroblastic to polygonal). Tumorigenic cells acquired a clear-cut membrane localization of adhesion molecules, a reorganization of the actin cytoskeleton, increased cell motility and invasiveness. In a 3-dimensional environment, tumorigenic cells showed a spherical morphology with cortical actin rings, suggesting a switch from a mesenchymal to an amoeboid ROCK-dependent movement. Accordingly, cell invasion decreased upon treatment with the ROCK inhibitor Y27632, but not with the matrix protease inhibitor Ro28-2653. The increased invasiveness of tumorigenic cen3tel cells was associated with a reduced expression of RhoE, a cellular inhibitor of ROCK. Ectopic RhoE expression decreased cen3tel invasion capability. These results point to RhoE and ROCK as regulators of invasiveness of mesenchymal tumor cells and indicate ROCK as a possible therapeutic target. The cen3tel telomerase immortalized cell line was obtained from primary cen3 fibroblasts, derived from a centenarian individual, by infection with an hTERT-containing retrovirus (Mondello et al., 2003). Cen3tel cells were used at different steps of propagation, reflecting different phases of transformation (Zongaro et al., 2005) to study variations in the migratory and invasive potential accompanying human fibroblast neoplastic transformation. Raw data files: *NORM.txt test is Cy5 and *DS.txt test is Cy3.
Project description:Cen3tel cells, obtained by telomerase immortalization of human fibroblasts, gradually underwent neoplastic transformation and became metastatic in immunocompromised mice. Neoplastic transformation was associated with a change in cell morphology (from fibroblastic to polygonal). Tumorigenic cells acquired a clear-cut membrane localization of adhesion molecules, a reorganization of the actin cytoskeleton, increased cell motility and invasiveness. In a 3-dimensional environment, tumorigenic cells showed a spherical morphology with cortical actin rings, suggesting a switch from a mesenchymal to an amoeboid ROCK-dependent movement. Accordingly, cell invasion decreased upon treatment with the ROCK inhibitor Y27632, but not with the matrix protease inhibitor Ro28-2653. The increased invasiveness of tumorigenic cen3tel cells was associated with a reduced expression of RhoE, a cellular inhibitor of ROCK. Ectopic RhoE expression decreased cen3tel invasion capability. These results point to RhoE and ROCK as regulators of invasiveness of mesenchymal tumor cells and indicate ROCK as a possible therapeutic target.
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:D122p53 mice (a model of D133p53 isoform) are tumour prone, have extensive inflammation and elevated serum IL-6. To investigate the role of IL-6 we crossed ∆122p53 mice with IL-6 deficient mice. Here we show that loss of IL-6 reduced JAK-STAT signalling, tumour incidence, and metastasis. We also show that D122p53 activates RhoA-ROCK signalling leading to tumour cell invasion which is IL-6 dependent and can be reduced by inhibition of JAK-STAT and RhoA-ROCK pathways. Similarly, we show that Δ133p53 activates the these pathways, resulting in invasive and migratory phenotypes, in colorectal cancer cells. Gene expression analysis of colorectal tumours showed enrichment of GPCR signalling associated with D133TP53 mRNA. Patients with elevated D133TP53 mRNA levels had a shorter disease free survival. Our results suggest that D133p53 promotes tumour invasion by activation of the JAK-STAT and RhoA-ROCK pathways and that patients whose tumours have high D133p53 may benefit from therapies targeting these pathways. In this dataset, we included the gene expression data from 35 colorectal cancers. These data were used to identify a list of enriched genesets associated with D133TP53 mRNA expression in colorectal tumours
Project description:We have used microarray technology to identify the transcriptional targets of Rho subfamily GTPases. This analysis indicated that murine fibroblasts transformed by these proteins show similar transcriptomal profiles. Functional annotation of the regulated genes indicate that Rho subfamily GTPases target a wide spectrum of biological functions, although loci encoding proteins linked to proliferation and DNA synthesis/transcription are up-regulated preferentially. Rho proteins promote four main networks of interacting proteins nucleated around E2F, c-Jun, c-Myc, and p53. Of those, E2F, c-Jun and c-Myc are essential for the maintenance of cell transformation. Inhibition of Rock, one of the main Rho GTPase targets, leads to small changes in the transcriptome of Rho-transformed cells. Rock inhibition decreases c-myc gene expression without affecting the E2F and c-Jun pathways. Loss-of-function studies demonstrate that c-Myc is important for the blockage of cell-contact inhibition rather than for promoting the proliferation of Rho-transformed cells. However, c-Myc overexpression does not bypass the inhibition of cell transformation induced by Rock blockage, indicating that c-Myc is essential, but not sufficient, for Rock-dependent transformation. These results reveal the complexity of the genetic program orchestrated by the Rho subfamily and pinpoint protein networks that mediate different aspects of the malignant phenotype of Rho-transformed cells Keywords: Rho/Rac GTPases, microarray, oncogenesis, proliferation, gene expression, transcription, Rock, c-Myc
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.