Project description:cMET is a well known oncogene whose activation is widely implicated in tumorigenesis and metastasis. To investigate the effects of acute activation of cMET signaling in the mammary epithelial cells, we stimulated MCF10A cells with increasing doses of HGF and analyzed the transcriptional alteration between PBS and HGF treated cells.
Project description:Neurofibromatosis type II (NF2) is a disease that needs new solutions. Vestibular schwannoma (VS) growth cause progressive hearing loss, and the standard treatment including surgery and radiotherapy, can further damage the nerve. There is an urgent need to identify an adjunct therapy that, by enhancing the efficacy of radiation, can help lower the radiation dose and preserve hearing. The mechanisms underlying deafness in NF2 are still unclear. One of the major limitations in studying tumor-induced hearing loss is the lack of mouse models that allows hearing test. Here we developed a cerebellopontine angle (CPA) schwannomas model that faithfully recapitulates the tumor-induced hearing loss. Using this model we discovered that cMET blockade by crizotinib (CRZ) enhanced schwannoma radiosensitivity by enhancing DNA damage, and CRZ treatment combined with low-dose radiation was as effective as high-dose radiation. CRZ treatment had no adverse effect on hearing; however, it did not affect tumor-induced hearing loss, presumably because cMET blockade did not change tumor HGF levels. cMET gene knockdown study independently confirmed the role of cMET pathway in mediating the effect of CRZ. Furthermore, we evaluated the translational potential of cMET blockade in human schwannomas. We found that human NF2-associated and sporadic VSs showed significantly elevated HGF expression and cMET activation compared to normal nerves, which correlated with tumor growth and cyst formation. Using organoid brain slice culture, cMET blockade inhibited the growth of patient-derived schwannomas. Our findings provide the rationale and necessary data for the clinical translation of combined cMET blockade with radiation therapy in NF2 patients. We found that human NF2-associated and sporadic VSs showed significantly elevated HGF expression and cMET activation compared to normal nerves, which correlated with tumor growth and cyst formation.
Project description:cMET is a well known oncogene whose activation is widely implicated in tumorigenesis and metastasis. To investigate the effects of acute inhibitoin of cMET signaling in the mammary tumors, we inhibited cMET activation in xenograft mammary tumors that were derived from a MET amplified mouse mammary tumor cell line and analyzed the transcriptional alteration between vehicle and MET inhibitor treated tumors.
Project description:DU145 prostate cancer cells were treated with 25 ng/ml hepatocyte growth factor (HGF) or vehicle for 2, 8, or 24 hours. HGF stimulates the cMET protein, a tyrosine kinase transmembrane protein. The aim of this study is to determine the role of the HGF/cMET pathway in immature cells of established prostate cancer. HGF stimulation of DU145 prostate cancer cell line led to cell migration in culture, formation of sprouts in Matrigel and inhibition of growth. These biological effects went together with induction of a stem-like phenotype as defined by up-regulation of CD49b, CD49f, CD44 and SOX9, and down-regulation of CD24 on gene-expression arrays and quantitative PCR. The shift towards a stem-like phenotype was reflected by protein modifications on FACS, Western blot, and enhanced rapid adhesion to collagen I. Small molecules SU11274 and PHA665752 were able to inhibit both morphologic and molecular HGF effects.
Project description:DU145 prostate cancer cells were treated with 25 ng/ml hepatocyte growth factor (HGF) or vehicle for 2, 8, or 24 hours. HGF stimulates the cMET protein, a tyrosine kinase transmembrane protein. The aim of this study is to determine the role of the HGF/cMET pathway in immature cells of established prostate cancer. HGF stimulation of DU145 prostate cancer cell line led to cell migration in culture, formation of sprouts in Matrigel and inhibition of growth. These biological effects went together with induction of a stem-like phenotype as defined by up-regulation of CD49b, CD49f, CD44 and SOX9, and down-regulation of CD24 on gene-expression arrays and quantitative PCR. The shift towards a stem-like phenotype was reflected by protein modifications on FACS, Western blot, and enhanced rapid adhesion to collagen I. Small molecules SU11274 and PHA665752 were able to inhibit both morphologic and molecular HGF effects. DU145 cells were stimulated for 2, 8 and 24 hours with 25 ng/ml HGF or vehicle. For each time point two arrays analyses were performed. One for cells stimulated with a vehicle and one for the HGF stimulated cells. Six arrays were performed in total in this study.
Project description:Gene expression in Madin Darby canine kidney cells grown for 7 days to confluence on Transwell filters and exposed to HGF +/- inhibitors of the MAPK pathway (MAPK is one of the pathways activated when HGF binds to the CMET receptor tyrosine kinase). We used microarrays to detail the program of gene expression in MDCK cells and identified genes specifically regulated by HGF via the MAPK pathway. Keywords: signaling pathway analysis
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: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.