Astrocytoma ; genetics ; metabolism ; Brain Neoplasms ; genetics ; metabolism ; Frizzled Receptors ; genetics ; metabolism ; Glioblastoma ; genetics ; metabolism ; Glioma ; genetics ; metabolism ; Humans ; Paraffin Embedding ; RNA, Messenger ; metabolism ; Receptors, G-Protein-Coupled ; genetics ; metabolism ; Signal Transduction ; Wnt2 Protein ; genetics ; metabolism ; beta Catenin ; genetics ; metabolism

Wnt signaling is known to be important for diverse embryonic and post-natal cellular events and be regulated by the proteins Dishevelled and Axin. Although Dishevelled is activated by Wnt and involved in signal transduction, it is not clear how Dishevelled-mediated signaling is turned off. We report that guanine nucleotide binding protein beta 2 (Gnb2; Gbeta2) bound to Axin and Gbeta2 inhibited Wnt mediated reporter activity. The inhibition involved reduction of the level of Dishevelled, and the Gbeta2gamma2 mediated reduction of Dishevelled was countered by increased expression of Axin. Consistent with these effects in HEK293T cells, injection of Gbeta2gamma2 into Xenopus embryos inhibited the formation of secondary axes induced either by XWnt8 or Dishevelled, but not by beta-catenin. The DEP domain of Dishevelled is necessary for both interaction with Gbeta2gamma2 and subsequent degradation of Dishevelled via the lysosomal pathway. Signaling induced by Gbeta2gamma2 is required because a mutant of Gbeta2, Gbeta2 (W332A) with lower signaling activity, had reduced ability to downregulate the level of Dishevelled. Activation of Wnt signaling by either of two methods, increased Frizzled signaling or transient transfection of Wnt, also led to increased degradation of Dishevelled and the induced Dishevelled loss is dependent on Gbeta1 and Gbeta2. Other studies with agents that interfere with PLC action and calcium signaling suggested that loss of Dishevelled is mediated through the following pathway: Wnt/Frizzled-->Gbetagamma-->PLC-->Ca+2/PKC signaling. Together the evidence suggests a novel negative feedback mechanism in which Gbeta2gamma2 inhibits Wnt signaling by degradation of Dishevelled.
Adaptor Proteins, Signal Transducing/genetics/*metabolism ; Animals ; Blastomeres/cytology/*metabolism ; Cell Line ; Embryonic Development/genetics ; *Feedback, Physiological ; Frizzled Receptors/genetics/metabolism ; GTP-Binding Proteins/genetics/*metabolism ; Gene Expression Regulation, Developmental ; Humans ; Mutation ; Phosphoproteins/genetics/*metabolism ; Protein Binding ; RNA, Small Interfering/genetics ; Repressor Proteins/genetics/metabolism ; Transfection ; Wnt Proteins/*genetics/metabolism ; Xenopus ; Xenopus Proteins/*genetics/metabolism

BACKGROUND/AIMS: This study aimed to better understand gene expression profiles of human hepatic stellate cell (HSC) activation and the relationship with the Wnt signaling pathway. METHODS: The global transcript levels in platelet derived growth factor-BB (PDGF-BB)-stimulated hTERT HSCs were analyzed using oligonucleotide microarrays. Oligonucleotide microarrays with 19K human oligo chips were performed to obtain gene expression profiles associated with proliferation in human hTERT HSCs. The microarray data was verified by real time quantitative PCR and expression of the components of Wnt signaling was analyzed by Western blot. RESULTS: Microarray data showed 243 up-regulated and 265 down-regulated genes in PDGF-BB-treated HSCs. The changes in expression of glypican3 and BH3 interacting domain death agonist (BID) mRNA in real time quantitative PCR, especially among the highly up- or down-regulated genes, were statistically consistent with the microarray data. The Wnt signaling pathway components, frizzled10 (FZD10) and calcium/calmodulin-dependent protein kinase II alpha (CAMK2A), showed increased expression in the short time course microarray and the up-regulation of FZD10 also occurred at the protein level. Our data showed various gene expression profiles during activation of human HSC. CONCLUSIONS: The up-regulated expression of FZD10 and CAMK2A suggests that the Wnt/Ca2+ signaling pathway is active in hTERT HSCs and may participate in HSC activation and proliferation
Angiogenesis Inducing Agents/*pharmacology ; Blotting, Western ; Calcium-Calmodulin-Dependent Protein Kinase Type 2/genetics/metabolism ; Cell Line ; Cell Proliferation ; Frizzled Receptors/genetics/metabolism ; Gene Expression Profiling ; Hepatic Stellate Cells/cytology/*metabolism ; Humans ; Oligonucleotide Array Sequence Analysis ; Platelet-Derived Growth Factor/*pharmacology ; Polymerase Chain Reaction ; Receptors, G-Protein-Coupled/genetics/metabolism ; *Signal Transduction ; Up-Regulation ; Wnt Proteins/genetics/*metabolism

OBJECTIVE: To investigate the effect of exosomal FZD10 derived from non-small cell lung cancer (NSCLC) cells on angiogenesis of human umbilical venous endothelial cells (HUVECs) and explore the possible mechanism. METHODS: We analyzed the expression of FZD10 in two NSCLC cell lines (95D and H1299 cells), normal human bronchial epithelial cells (BEAS-2B cells) and their exosomes isolated by ultracentrifugation. Cultured HUVECs were treated with the exosomes derived from NSCLC cells or NSCLC cells transfected with FZD10-siRNA, and the changes in tube formation ability of the cells were analyzed using an in vitro angiogenesis assay. ELISA was performed to determine the concentration of VEGFA and Ang-1 in the conditioned media of HUVECs, and RT-qPCR was used to analyze the mRNA levels of VEGFA and Ang-1 in the HUVECs. The effects of exosomal FZD10 on the activation of PI3K, Erk1/2 and YAP/TAZ signaling pathways were evaluated using Western blotting. RESULTS: Compared with BEAS-2B cells and their exosomes, 95D and H1299 cells and their exosomes all expressed high levels of FZD10 (P < 0.01). The exosomes derived from 95D and H1299 cells significantly enhanced tube formation ability and increased the expressions of VEGFA and Ang-1 protein and mRNA in HUVECs (P < 0.01), but FZD10 knockdown in 95D and H1299 cells obviously inhibited these effects of the exosomes. Exosomal FZD10 knockdown suppressed the activation of PI3K and Erk1/2 signaling pathways, but had no obvious effect on the activation of YAP/TAZ signaling pathway. CONCLUSION Exosomal FZD10 derived from NSCLC cells promotes HUVEC angiogenesis in vitro, the mechanism of which may involve the activation of PI3K and Erk1/2 signaling pathways.
Carcinoma, Non-Small-Cell Lung/metabolism* ; Cell Proliferation ; Culture Media, Conditioned ; Exosomes ; Frizzled Receptors/metabolism* ; Human Umbilical Vein Endothelial Cells/metabolism* ; Humans ; Lung Neoplasms/metabolism* ; MicroRNAs/genetics* ; Neovascularization, Pathologic/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; RNA, Messenger/metabolism* ; RNA, Small Interfering/metabolism*

OBJECTIVETo investigate the action mechanisms of the FZD5 gene in prostate cancer bone metastasis and search for some new treatments for this disease.

METHODSWe determined the expression level of the FZD5 gene in prostate cancer PC3 cells and, after transfection of siRNA into the PC3 cells and silence of the FZD5 gene, observed the changes in the migration and proliferation of the cells. We established the model of prostate cancer bone metastasis by tibial injection of prostate cancer cells in the nude mice. Then we injected control siRNA and FZD5-silenced siRNA into the tibia of the mice followed by evaluation of tumor-induced bone destruction by X-ray imaging at 0, 1, and 3 weeks and by HE staining at 3 weeks after injection.

RESULTSAfter transfection of FZD5-silenced siRNA into the prostate cancer PC3 cells, the expression of the FZD5 gene was decreased about 70%. The rate of cell proliferation was significantly lower in the gene silencing group than in the control (P < 0.05), and that of cell migration dropped by 30% in the former as compared with the latter group at 48 hours after FZD5 silencing (P < 0.05). At 3 weeks after injection of control siRNA or FZD5-silenced siRNA into the tibia of the mice, osteolytic damage was observed in both groups, though less in the FZD5 silencing group, with only a few remaining bone trabeculae visible.

CONCLUSIONSilencing the FZD5 gene can reduce the migration and proliferation of prostate cancer cells, help to suppress bone metastasis and destruction, and thereby improve the survival rate and quality of life of the patients.

Animals ; Bone Neoplasms ; genetics ; prevention & control ; secondary ; Cell Line, Tumor ; Cell Movement ; genetics ; Cell Proliferation ; genetics ; Frizzled Receptors ; genetics ; physiology ; Gene Expression ; Gene Silencing ; Male ; Mice ; Mice, Nude ; Osteolysis ; Prostatic Neoplasms ; genetics ; metabolism ; pathology ; Quality of Life ; RNA, Small Interfering ; administration & dosage ; genetics ; Transfection

SUV39H1 is a histone 3 lysine 9 (H3K9)-specific methyltransferase that is important for heterochromatin formation and the regulation of gene expression. Chaetocin specifically inhibits SUV39H1, resulted in H3K9 methylation reduction as well as reactivation of silenced genes in cancer cells. Histone deacetylase (HDAC) inhibitors inhibit deacetylases and accumulate high levels of acetylation lead to cell cycle arrest and apoptosis. In this study, we demonstrated that treatment with chaetocin enhanced apoptosis in human leukemia HL60, KG1, Kasumi, K562, and THP1 cells. In addition, chaetocin induced the expression of cyclin-dependent kinase inhibitor 2B (p15), E-cadherin (CDH1) and frizzled family receptor 9 (FZD9) through depletion of SUV39H1 and reduced H3K9 methylation in their promoters. Co-treatment with chaetocin and HDAC inhibitor trichostatin A (TSA) dramatically increased apoptosis and produced greater activation of genes. Furthermore, this combined treatment significantly increased loss of SUV39H1 and reduced histone H3K9 trimethylation responses accompanied by increased acetylation. Importantly, co-treatment with chaetocin and TSA produced potent antileukemic effects in leukemia cells derived from patients. These in vitro findings suggest that combination therapy with SUV39H1 and HDAC inhibitors may be of potential value in the treatment of leukemia.
Acetylation/drug effects ; Adolescent ; Adult ; Aged ; Apoptosis/*drug effects ; Cadherins/metabolism ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p15/metabolism ; DNA Methylation/drug effects ; Enzyme Inhibitors/therapeutic use/*toxicity ; Frizzled Receptors/metabolism ; Gene Expression Regulation/drug effects ; HL-60 Cells ; Histone Deacetylase Inhibitors/therapeutic use/*toxicity ; Histone-Lysine N-Methyltransferase/*antagonists & inhibitors/metabolism ; Histones/genetics/metabolism ; Humans ; Hydroxamic Acids/therapeutic use/*toxicity ; K562 Cells ; Leukemia/drug therapy/metabolism/pathology ; Leukemia, Myeloid, Acute/genetics/metabolism/pathology ; Male ; Middle Aged ; Piperazines/therapeutic use/toxicity ; Promoter Regions, Genetic ; Young Adult