NORE1A (RASSF5) is a tumor suppressor of the RASSF family that is often down-regulated in human tumors. NORE1A has multiple roles in controlling cellular homeostasis, one of them being regulating levels of β-catenin ...NORE1A (RASSF5) is a tumor suppressor of the RASSF family that is often down-regulated in human tumors. NORE1A has multiple roles in controlling cellular homeostasis, one of them being regulating levels of β-catenin by binding and modulating the ubiquitin ligase substrate recognition factor β-TrCP. β-catenin is a major executor of the Wnt pathway. The ubiquitin SCF-β-TrCP ligase complex acts on a phospho-degron site in β-catenin that can be phosphorylated by GSK-3β. We now show that in addition to binding β-TrCP, NORE1A also promotes the phosphorylation of the β-catenin phospho-degron by complexing with the kinase GSK-3β. Indeed, NORE1A enhances the formation of a GSK-3β/β-TrCP complex. A structural mutant of NORE1A that retains β-TrCP binding but will no longer interact with GSK-3β inhibits the β-catenin degrading action of NORE1A. The GSK-3β interaction with NORE1A plays an important role in the biology of NORE1A as a GSK-3β inhibitor blocks NORE1A induced senescence. Thus, we identify a new role for the tumor suppressor NORE1A: The regulation of GSK-3β. GSK-3β has many other substrates including multiple transcription factors and co-activators such as p53 and the Hippo component TAZ. The work implies that NORE1A may be able to influence all of them via this new kinase scaffolding interaction.展开更多
An important factor in the emergence and progre sion of osteosarcoma(OS)is the dysregulated expression of microRNAs(miRNAs).Transcription factor 7-like 1(TCF7LI),a member of the T cell factor/lymphoid enhancer factor(...An important factor in the emergence and progre sion of osteosarcoma(OS)is the dysregulated expression of microRNAs(miRNAs).Transcription factor 7-like 1(TCF7LI),a member of the T cell factor/lymphoid enhancer factor(TCF/LEF)transcription factor family,interacts with the Wnt signaling pathway regulator β-catenin and acts as a DNA-specific binding protein.This study sought to elucidate the impact of the interaction between miR 3293p and TCF7L1 on.the growth and apoptosis of OS and analyze the regulatory expression relationship between miRNA and mRNA in osteosarcoma cells using a variety of approaches.MiR329-3p was significantly downregulated,while TCF7L1 was considerably up-regulated in all examined OS cell lines.Additionally,a clinical comparison study was performed using the TCGA database.Subsequently,the regulatory relationship between miR-329-3p and TCF7L1 on the proliferation and apoptosis of OS cells was verified through in vitro and in vivo experiments.When miR 329-3p was transfected into the OS cell line,the expression of TCF7L1 decreased,the proliferation of OS cells was inhibited,the cytoskeleton disintegrated,and the nucleus condensed to fom apoptotic bodies.The expression of proteins that indicate apoptosis increased simultaneously.The cell cycle was arrested in the G0/G1 phase,and the G1/S transition was blocked.The introduction of miR 3293p also inhibited downstream Cyclin D1 of the Wnt pathway.Xenograf experiments indicated that the overexpression of miR-329-3p signi ficanly inhibited the growth of OS xenografts in nude mice,and the expression of TCF7L1 and C-Myc in tumor tssues decreased.MiR 329-3p was significantly reduced in OS cells and played a suppressive role in tumorigenesis and proliferation by targeting TCF7L1 both in vitro and in vivo.Osteosarcoma cell cycle arrest and pathway inhibition were observed upon the regulation of TCF7LI by miR 3293p.Summarizing these results,it can be inferred that miR.3293p exerts anticancer efects in osteosarcoma by inhibiting TCF7L1.展开更多
文摘NORE1A (RASSF5) is a tumor suppressor of the RASSF family that is often down-regulated in human tumors. NORE1A has multiple roles in controlling cellular homeostasis, one of them being regulating levels of β-catenin by binding and modulating the ubiquitin ligase substrate recognition factor β-TrCP. β-catenin is a major executor of the Wnt pathway. The ubiquitin SCF-β-TrCP ligase complex acts on a phospho-degron site in β-catenin that can be phosphorylated by GSK-3β. We now show that in addition to binding β-TrCP, NORE1A also promotes the phosphorylation of the β-catenin phospho-degron by complexing with the kinase GSK-3β. Indeed, NORE1A enhances the formation of a GSK-3β/β-TrCP complex. A structural mutant of NORE1A that retains β-TrCP binding but will no longer interact with GSK-3β inhibits the β-catenin degrading action of NORE1A. The GSK-3β interaction with NORE1A plays an important role in the biology of NORE1A as a GSK-3β inhibitor blocks NORE1A induced senescence. Thus, we identify a new role for the tumor suppressor NORE1A: The regulation of GSK-3β. GSK-3β has many other substrates including multiple transcription factors and co-activators such as p53 and the Hippo component TAZ. The work implies that NORE1A may be able to influence all of them via this new kinase scaffolding interaction.
基金The Fund of National Cancer Center Research and Development(26-A-4),The Grants-in-Aid for Scientific Research(Grant Nos.15K10451,16K10866 and 16K20063)from Japan Society for the Promotion of Science.
文摘An important factor in the emergence and progre sion of osteosarcoma(OS)is the dysregulated expression of microRNAs(miRNAs).Transcription factor 7-like 1(TCF7LI),a member of the T cell factor/lymphoid enhancer factor(TCF/LEF)transcription factor family,interacts with the Wnt signaling pathway regulator β-catenin and acts as a DNA-specific binding protein.This study sought to elucidate the impact of the interaction between miR 3293p and TCF7L1 on.the growth and apoptosis of OS and analyze the regulatory expression relationship between miRNA and mRNA in osteosarcoma cells using a variety of approaches.MiR329-3p was significantly downregulated,while TCF7L1 was considerably up-regulated in all examined OS cell lines.Additionally,a clinical comparison study was performed using the TCGA database.Subsequently,the regulatory relationship between miR-329-3p and TCF7L1 on the proliferation and apoptosis of OS cells was verified through in vitro and in vivo experiments.When miR 329-3p was transfected into the OS cell line,the expression of TCF7L1 decreased,the proliferation of OS cells was inhibited,the cytoskeleton disintegrated,and the nucleus condensed to fom apoptotic bodies.The expression of proteins that indicate apoptosis increased simultaneously.The cell cycle was arrested in the G0/G1 phase,and the G1/S transition was blocked.The introduction of miR 3293p also inhibited downstream Cyclin D1 of the Wnt pathway.Xenograf experiments indicated that the overexpression of miR-329-3p signi ficanly inhibited the growth of OS xenografts in nude mice,and the expression of TCF7L1 and C-Myc in tumor tssues decreased.MiR 329-3p was significantly reduced in OS cells and played a suppressive role in tumorigenesis and proliferation by targeting TCF7L1 both in vitro and in vivo.Osteosarcoma cell cycle arrest and pathway inhibition were observed upon the regulation of TCF7LI by miR 3293p.Summarizing these results,it can be inferred that miR.3293p exerts anticancer efects in osteosarcoma by inhibiting TCF7L1.
