Abstract. SHH, IHH, and DHH are lipid-modified secreted proteins binding to Patched receptors, and CDON, BOC or GAS1 co-receptors. In the absence of Hedgehog signaling, GLI1 is transcriptionally repressed, GLI2 is phosphorylated by GSK3 and CK1 for the FBXW11 (ßTRCP2)-mediated degradation, and GLI3 is processed to a cleaved repressor. In the presence of Hedgehog signaling, Smoothened is relieved from Patched-mediated suppression due to the Hedgehogdependent internalization of Patched, which leads to MAP3K10 (MST) activation and SUFU inactivation for the stabilization and nuclear accumulation of GLI family members. GLI activators then upregulate CCND1, CCND2 for cell cycle acceleration, FOXA2, FOXC2, FOXE1, FOXF1, FOXL1, FOXP3, POU3F1, RUNX2, SOX13, TBX2 for cell fate determination, JAG2, INHBC, and INHBE for stem cell signaling regulation. Hedgehog signals also upregulate SFRP1 in mesenchymal cells for WNT signaling regulation. Epithelial-to-mesenchymal transition (EMT) during embryogenesis, adult tissue homeostasis and carcinogenesis is characterized by class switch from E-cadherin to N-cadherin. SNAI1 (Snail), SNAI2 (Slug), SNAI3, ZEB1, ZEB2 (SIP1), KLF8, TWIST1, and TWIST2 are EMT regulators repressing CDH1 gene encoding E-cadherin. Hedgehog signals induce JAG2 upregulation for Notch-CSL-mediated SNAI1 upregulation, and also induce TGFß1 secretion for ZEB1 and ZEB2 upregulation via TGFß receptor and NF-κB. TGFß-mediated downregulation of miR-141, miR-200a, miR-200b, miR-200c, miR-205, and miR-429 results in upregulation of ZEB1 and ZEB2 proteins. Hedgehog signaling activation indirectly leads to EMT through FGF, Notch, TGFß signaling cascades, and miRNA regulatory networks. miRNAs targeted to stem cell signaling components or EMT regulators are potent drug targets; however, off-target effects should be strictly controlled before clinical application of synthetic miRNA. Peptide mimetic and RNA aptamer could also be utilized as Hedgehog signaling inhibitors or EMT suppressors. Contents1. Introduction 2. Hedgehog signaling pathway 3. Epithelial-to-mesenchymal transition (EMT) 4. Hedgehog and EMT 5. MicroRNA (miRNA) 6. Perspectives IntroductionHedgehog family members are key regulators of embryogenesis, adult tissue homeostasis, and carcinogenesis (1-5). Genetic alterations and aberrant expression of Hedgehog signaling molecules in medulloblastoma, glioma, basal cell carcinoma, lung cancer, esophageal cancer, gastric cancer, pancreatic cancer, prostate cancer, and ovarian cancer have been reported, and reviewed elsewhere.Hedgehog signaling cascade cross talks with WNT, Notch, EGF/FGF, and TGFß/Activin/Nodal/BMP signaling cascades to constitute the stem cell signaling network (6-9). Deregulation of the stem cell signaling network due to the accumulation of germline mutation, SNP, chronic inflammation, epigenetic change, and genetic alteration leads to carcinogenesis (10).Epithelial cells undergo fibroblastoid morphological changes associated with increased motility or invasiveness due to decreased cell-cell ad...
Abstract. WNT5A is a cancer-associated gene involved in invasion and metastasis of melanoma, breast cancer, pancreatic cancer, and gastric cancer. WNT5A transduces signals through Frizzled, ROR1, ROR2 or RYK receptors to ß-catenin-TCF/ LEF, DVL-RhoA-ROCK, DVL-RhoB-Rab4, DVL-Rac-JNK, DVL-aPKC, Calcineurin-NFAT, MAP3K7-NLK, MAP3K7-NF-κB, and DAG-PKC signaling cascades in a contextdependent manner. SNAI1 (Snail), CD44, G3BP2, and YAP1 are WNT5A target genes. We and other groups previously reported that IL6-or LIF-induced signaling through JAK-STAT3 signaling cascade is involved in WNT5A upregulation (STAT3-WNT5A signaling loop). Here, refined integrative genomic analyses of WNT5A were carried out to elucidate other mechanisms of WNT5A transcription. The WNT5A gene was found to encode two isoforms by using alternative first exons 1A and 1B. Quadruple Smad-binding elements (SBEs), single Sp1-binding site (GC-box), PPARÁ-binding site, C/EBPbinding site and bHLH-binding site within the promoter A region, 5'-adjacent to exon 1A, were conserved in human WNT5A, chimpanzee WNT5A, mouse Wnt5a, and rat Wnt5a. NF-κB-binding site, CUX1-binding site, double SBEs and double GC-boxes within the promoter B region, 5'-adjacent to exon 1B, were conserved in mammalian WNT5A orthologs. Quadruple FOX-binding sites and double SBEs within ultraconserved intron 1 were also conserved in mammalian WNT5A orthologs. Conserved NF-κB-binding site within the WNT5A promoter B region elucidated the mechanisms that TNF· and toll-like receptor (TLR) signals upregulate WNT5A via MAP3K7. Quadruple FOX-binding sites rather than GLIbinding site revealed that Hedgehog signals induce WNT5A upregulation indirectly via FOX family members, such as FOXA2, FOXC2, FOXE1, FOXF1 and FOXL1. TGFß signals were found to upregulate WNT5A expression directly through the Smad complex, and also indirectly through Smadinduced CUX1 and MAP3K7-mediated NF-κB. Together these facts indicate that WNT5A is transcribed based on multiple mechanisms, such as NF-κB, Hedgehog, TGFß, and Notch signaling cascades.
Abstract. FGFR2 gene at human chromosome 10q26 encodes FGFR2b and FGFR2c isoforms functioning as FGF receptors with distinct expression domain and ligand specificity. FGFR2 plays oncogenic and anti-oncogenic roles in a contextdependent manner. Single nucleotide polymorphisms (SNPs) within intron 2 of FGFR2 gene are associated with breast cancer through allelic FGFR2 upregulation. Missense mutations or copy number gains of FGFR2 gene occur in breast cancer and gastric cancer to activate FGFR2 signaling. Aberrant FGFR2 signaling activation induces proliferation and survival of tumor cells. The class switch from FGFR2b to FGFR2c occurs during progression of prostate cancer and bladder cancer because of spliceosome dysregulation. In addition, epidermal Fgfr2b knockout mice show increased sensitivity to chemical carcinogenesis partly due to the failure of Nfe2l2 (Nrf2)-mediated detoxification of reactive oxygen species (ROS). Loss of FGFR2b signaling induces epithelialto-mesenchymal transition (EMT) and unruly ROS. FGFR2 signaling dysregulation due to the accumulation of epigenetic modifications and genetic alterations during chronic inflammation, smoking, increased caloric uptake, and decreased exercise leads to carcinogenesis. PD173074, SU5402, AZD2171, and Ki23057 are small-molecule FGFR inhibitors. Human antibody, peptide mimetic, RNA aptamer, siRNA, and synthetic microRNA (miRNA) are emerging technologies to be applied for cancer therapeutics targeted to FGFR2. Because novel sequence technology and peta-scale supercomputer are opening up the sequence era following the genome era, personalized medicine prescribing targeted drugs based on germline and/or somatic genomic information is coming reality. Application of FGFR2 inhibitors for cancer treatment in patients with FGFR2 mutation or gene amplification is beneficial; however, that for cancer prevention in people with FGFR2 risk allele might be disadvantageous due to the impediment of a cytoprotective mechanism against oxidative stress.
Abstract. GLI family members are zinc-finger transcription factors, which are involved in embryogenesis and carcinogenesis through transcription regulation of GLI1, CCND1, CCND2, FOXA2, FOXC2, RUNX2, SFRP1, and JAG2. GLI1
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