{"gene":"FZD8","run_date":"2026-06-09T23:54:44","timeline":{"discoveries":[{"year":2015,"finding":"A human-accelerated regulatory enhancer (HARE5) physically contacts the core Fzd8 promoter in the mouse embryonic neocortex (shown by chromosome conformation capture), and transgenic mice expressing Fzd8 under the human HARE5 show accelerated neural progenitor cell cycle and increased brain size compared to mice with the chimpanzee HARE5, demonstrating that enhanced FZD8 expression during corticogenesis alters cell-cycle dynamics of neural progenitor cells.","method":"Chromosome conformation capture (3C), transgenic mouse lines (Hs-HARE5::Fzd8 vs Pt-HARE5::Fzd8), cell-cycle analysis, brain size measurement","journal":"Current biology : CB","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (3C, transgenic rescue, phenotypic quantification) in a single rigorous study with functional validation","pmids":["25702574"],"is_preprint":false},{"year":2014,"finding":"FZD8 is essential for the interaction between c-Met and Wnt/β-catenin signaling in head and neck squamous carcinoma stem-like cells (HN-CSC); c-Met inhibition downregulates FZD8 via the ERK/c-Fos cascade, and ectopic FZD8 expression rescues the impaired stem-like phenotype caused by c-Met inhibition.","method":"siRNA silencing, ectopic overexpression rescue assay, pharmacologic c-Met inhibition (PF-2341066), sphere formation and tumor initiation assays, mouse xenograft model","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic rescue (FZD8 OE reverses c-Met KD phenotype) plus pharmacologic inhibition, single lab","pmids":["25320014"],"is_preprint":false},{"year":2017,"finding":"Wild-type p53 transcriptionally represses FZD8 by directly binding the FZD8 promoter; FZD8 overexpression activates canonical Wnt/β-catenin signaling and promotes prostate cancer cell migration, invasion, stem cell-like phenotypes in vitro, and bone metastasis in vivo, while FZD8 silencing suppresses these effects.","method":"Chromatin immunoprecipitation (ChIP) for p53 at FZD8 promoter, FZD8 overexpression and siRNA knockdown, in vitro migration/invasion assays, in vivo bone metastasis mouse model","journal":"Cancer letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP plus loss- and gain-of-function with in vivo validation, single lab","pmids":["28602974"],"is_preprint":false},{"year":2013,"finding":"FZD8-mediated Wnt signaling contributes to chemotherapy resistance in triple-negative breast cancer; FZD8 is upregulated in residual tumor cells after cisplatin/TRAIL treatment, and siRNA-mediated FZD8 inhibition reduces β-catenin and survivin levels and increases apoptosis in the presence of these agents.","method":"Gene expression profiling, siRNA knockdown of FZD8, Western blot (β-catenin, survivin), apoptosis assay, in vivo NOD/SCID xenograft with fluorescent imaging","journal":"Molecular cancer therapeutics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with defined molecular readouts (β-catenin, survivin) and in vivo validation, single lab","pmids":["23445611"],"is_preprint":false},{"year":2015,"finding":"FZD8 is a direct target of miR-375 in fibroblast-like synoviocytes; miR-375 suppresses FZD8 expression and downstream canonical Wnt/β-catenin signaling (validated by firefly luciferase reporter assay), and stabilized β-catenin blocks the effects of miR-375, placing FZD8 upstream of β-catenin in the canonical Wnt pathway in arthritis synoviocytes.","method":"Luciferase reporter assay, Western blot, RT-qPCR, RNA interference (β-catenin knockdown), ELISA, ChIP","journal":"Immunology letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — luciferase reporter validation plus epistasis (stabilized β-catenin rescue), single lab","pmids":["25619565"],"is_preprint":false},{"year":2023,"finding":"FZD8-specific antibodies (pF8_AC3 and sF8_AG6) were identified using a synthetic library guided by the structure of the pF8_AC3–FZD8 complex; cell-based assays showed these antibodies selectively block FZD8-mediated Wnt signaling activation.","method":"Synthetic antibody library selection, structural determination of pF8_AC3–FZD8 complex, cell-based Wnt signaling reporter assay","journal":"International journal of biological macromolecules","confidence":"Medium","confidence_rationale":"Tier 1–2 / Weak — structure-guided antibody identification with cell-based functional validation, single lab, single study","pmids":["37926311"],"is_preprint":false},{"year":2025,"finding":"USP14 interacts with FZD8 (shown by Co-IP and GST pull-down) and stabilizes FZD8 protein through deubiquitination; USP14 silencing inhibits the Wnt/β-catenin pathway via reduced FZD8 levels, and FZD8 overexpression rescues the cellular effects of USP14 knockdown in IL-1β-treated chondrocytes.","method":"Co-immunoprecipitation, GST pull-down, ubiquitination assay, Western blot, siRNA knockdown, overexpression rescue, MTT, EdU, flow cytometry, ELISA","journal":"Immunobiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal binding assays (Co-IP + GST pull-down) plus ubiquitination assay and genetic rescue, single lab","pmids":["40318610"],"is_preprint":false},{"year":2025,"finding":"ALKBH1 demethylase regulates FZD8 mRNA through m7G methylation, suppressing the FZD8/β-catenin signaling axis; ALKBH1 overexpression reduces FZD8 levels and enhances osteosarcoma chemosensitivity to doxorubicin in vitro and in vivo.","method":"RIP sequencing, m7G-MeRIP-qPCR, RIP-qPCR, rescue assays, transcriptome sequencing, in vitro and in vivo functional assays","journal":"International journal of biological macromolecules","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — m7G-MeRIP-qPCR and RIP-seq directly link ALKBH1 to FZD8 mRNA modification, with in vivo validation, single lab","pmids":["41274478"],"is_preprint":false},{"year":2025,"finding":"Fzd8 knockout in mice (CRISPR/Cas9) leads to increased osteoclasts and decreased osteoblasts, and is associated with altered expression of Fzd10, Lta, and proteins Itgb3 and RANK, establishing a role for FZD8 in bone remodeling/homeostasis.","method":"CRISPR/Cas9 knockout mouse model, histology (osteoclast/osteoblast quantification), RNA-seq (DEG analysis), pathway/gene set enrichment analysis, protein expression analysis","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 2 / Weak — CRISPR KO with defined bone phenotype but single preprint, no replication, mechanistic pathway placement largely inferred from DEG analysis","pmids":["bio_10.1101_2025.01.19.633799"],"is_preprint":true},{"year":2005,"finding":"Comparative genomics established that vertebrate FZD8 orthologs are seven-transmembrane receptors containing a Frizzled (Fz) domain in the N-terminal extracellular region, a leucine zipper motif around the fifth transmembrane domain, a Dishevelled (Dvl)-binding motif in the C-terminal cytoplasmic region, and conserved N-linked glycosylation sites.","method":"Bioinformatics/comparative genomics sequence analysis across vertebrate orthologs","journal":"Oncology reports","confidence":"Low","confidence_rationale":"Tier 4 / Moderate — computational/comparative genomics analysis only, no direct biochemical validation of domain functions","pmids":["15809770"],"is_preprint":false}],"current_model":"FZD8 is a seven-transmembrane Frizzled receptor that acts as a canonical Wnt/β-catenin signaling receptor; its expression is transcriptionally repressed by wild-type p53 and epigenetically regulated by ALKBH1-mediated m7G methylation of its mRNA, while at the protein level it is stabilized by the deubiquitinase USP14; FZD8 mediates downstream Wnt/β-catenin activation to promote cancer cell stemness, migration, invasion, chemoresistance, and bone metastasis, and in neural development its expression level (controlled by a human-accelerated enhancer HARE5) directly sets the pace of neural progenitor cell-cycle progression and neocortical size."},"narrative":{"mechanistic_narrative":"FZD8 is a seven-transmembrane Frizzled-family receptor that transduces canonical Wnt/β-catenin signaling and, through this pathway, governs both neural progenitor proliferation during corticogenesis and pro-malignant cell behavior across multiple cancers [PMID:25702574, PMID:28602974]. In neural development, FZD8 expression is set by the human-accelerated enhancer HARE5, which physically contacts the Fzd8 promoter; elevated FZD8 accelerates the neural progenitor cell cycle and increases neocortical size [PMID:25702574]. In cancer, FZD8 acts upstream of β-catenin to drive stem-like phenotypes, migration, invasion, and chemoresistance: it is required for cross-talk between c-Met and Wnt signaling in head and neck squamous carcinoma stem-like cells [PMID:25320014], promotes prostate cancer migration, invasion, and bone metastasis [PMID:28602974], and sustains β-catenin and survivin to confer chemoresistance in triple-negative breast cancer [PMID:23445611]. FZD8 abundance is controlled at several layers: it is transcriptionally repressed by wild-type p53 binding its promoter [PMID:28602974] and by miR-375 targeting its transcript [PMID:25619565], its mRNA is regulated by ALKBH1-mediated m7G methylation that suppresses the FZD8/β-catenin axis [PMID:41274478], and its protein is stabilized by the deubiquitinase USP14 [PMID:40318610]. FZD8 also contributes to bone homeostasis, with knockout shifting the balance toward osteoclasts over osteoblasts [PMID:bio_10.1101_2025.01.19.633799].","teleology":[{"year":2005,"claim":"Defined the predicted architecture of FZD8 as a Wnt-receptor-type protein, establishing the structural framework for its receptor function.","evidence":"Comparative genomics sequence analysis across vertebrate orthologs identifying an N-terminal Fz domain, leucine zipper, Dvl-binding motif, and glycosylation sites","pmids":["15809770"],"confidence":"Low","gaps":["Computational prediction only, no biochemical validation of domain functions","Does not demonstrate ligand binding or signaling"]},{"year":2013,"claim":"Linked FZD8 to therapy resistance, showing FZD8-driven Wnt signaling protects tumor cells from chemotherapy.","evidence":"siRNA knockdown of FZD8 with β-catenin/survivin readouts and NOD/SCID xenograft in triple-negative breast cancer","pmids":["23445611"],"confidence":"Medium","gaps":["Ligand and receptor activation mechanism not addressed","Single lab, no direct structural binding data"]},{"year":2014,"claim":"Positioned FZD8 as a node connecting c-Met to Wnt/β-catenin signaling required for cancer stem-like phenotypes.","evidence":"siRNA silencing, ectopic FZD8 rescue of c-Met-inhibited phenotype, pharmacologic c-Met inhibition, and xenografts in head and neck carcinoma stem-like cells","pmids":["25320014"],"confidence":"Medium","gaps":["ERK/c-Fos to FZD8 transcriptional link inferred, not directly mapped at the promoter","Single lab"]},{"year":2015,"claim":"Demonstrated that the level of FZD8 expression directly tunes neural progenitor cell-cycle pace and brain size, revealing a developmental role beyond cancer.","evidence":"Chromosome conformation capture plus humanized HARE5::Fzd8 transgenic mice with cell-cycle and brain-size quantification","pmids":["25702574"],"confidence":"High","gaps":["Downstream Wnt effectors mediating cell-cycle change in progenitors not dissected","Receptor signaling mechanism inferred from expression dosage"]},{"year":2015,"claim":"Identified miR-375 as a post-transcriptional repressor placing FZD8 upstream of β-catenin in synoviocytes.","evidence":"Luciferase reporter validation of miR-375 targeting plus β-catenin epistasis rescue in fibroblast-like synoviocytes","pmids":["25619565"],"confidence":"Medium","gaps":["Effect generality across cell types unknown","Single lab"]},{"year":2017,"claim":"Established direct transcriptional repression of FZD8 by wild-type p53 and tied FZD8 to prostate cancer bone metastasis.","evidence":"ChIP of p53 at the FZD8 promoter with gain/loss-of-function and an in vivo bone metastasis model","pmids":["28602974"],"confidence":"Medium","gaps":["Mechanism linking FZD8/Wnt to the metastatic bone niche not resolved","Single lab"]},{"year":2023,"claim":"Provided structure-guided antibodies that selectively block FZD8-mediated Wnt activation, confirming FZD8 as a tractable signaling receptor.","evidence":"Synthetic antibody library selection, structure of the pF8_AC3–FZD8 complex, and cell-based Wnt reporter assays","pmids":["37926311"],"confidence":"Medium","gaps":["Functional antibody activity shown only in cell-based reporters, not in vivo","Single study"]},{"year":2025,"claim":"Defined two additional regulatory layers controlling FZD8 abundance: USP14-mediated deubiquitination stabilizing FZD8 protein and ALKBH1-mediated m7G mRNA methylation suppressing the FZD8/β-catenin axis.","evidence":"Co-IP/GST pull-down with ubiquitination assays and rescue in chondrocytes; RIP-seq and m7G-MeRIP-qPCR with in vivo doxorubicin chemosensitivity in osteosarcoma","pmids":["40318610","41274478"],"confidence":"Medium","gaps":["Direct deubiquitination site on FZD8 not mapped","Both findings from single labs in distinct disease contexts"]},{"year":2025,"claim":"Implicated FZD8 in bone remodeling, with knockout shifting osteoclast/osteoblast balance.","evidence":"CRISPR/Cas9 Fzd8 knockout mouse with histology and RNA-seq DEG analysis (preprint)","pmids":["bio_10.1101_2025.01.19.633799"],"confidence":"Low","gaps":["Single preprint, no replication","Pathway placement (Fzd10, RANK, Itgb3) inferred from DEG analysis, not mechanistically validated"]},{"year":null,"claim":"How FZD8 ligand selectivity, co-receptor engagement, and Dishevelled coupling produce context-specific outputs in development versus cancer remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No direct mapping of which Wnt ligands activate FZD8 in each setting","Mechanism distinguishing developmental cell-cycle control from oncogenic invasion not defined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[0,2,5]},{"term_id":"GO:0038024","term_label":"cargo receptor activity","supporting_discovery_ids":[5,9]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[9,5]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,2,3,4]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[2,3,7]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0]}],"complexes":[],"partners":["USP14","MET"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9H461","full_name":"Frizzled-8","aliases":[],"length_aa":694,"mass_kda":73.3,"function":"Receptor for Wnt proteins. Component of the Wnt-Fzd-LRP5-LRP6 complex that triggers beta-catenin signaling through inducing aggregation of receptor-ligand complexes into ribosome-sized signalosomes. The beta-catenin canonical signaling pathway leads to the activation of disheveled proteins, inhibition of GSK-3 kinase, nuclear accumulation of beta-catenin and activation of Wnt target genes. A second signaling pathway involving PKC and calcium fluxes has been seen for some family members, but it is not yet clear if it represents a distinct pathway or if it can be integrated in the canonical pathway, as PKC seems to be required for Wnt-mediated inactivation of GSK-3 kinase. Both pathways seem to involve interactions with G-proteins. May be involved in transduction and intercellular transmission of polarity information during tissue morphogenesis and/or in differentiated tissues. Coreceptor along with RYK of Wnt proteins, such as WNT1","subcellular_location":"Membrane; Golgi apparatus; Cell membrane","url":"https://www.uniprot.org/uniprotkb/Q9H461/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/FZD8","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/FZD8","total_profiled":1310},"omim":[{"mim_id":"621360","title":"HUMAN-ACCELERATED REGULATORY ENHANCER 5","url":"https://www.omim.org/entry/621360"},{"mim_id":"612786","title":"CYCLIN Y; CCNY","url":"https://www.omim.org/entry/612786"},{"mim_id":"610574","title":"R-SPONDIN 3; RSPO3","url":"https://www.omim.org/entry/610574"},{"mim_id":"606845","title":"GOLGI-ASSOCIATED PDZ AND COILED-COIL DOMAINS-CONTAINING PROTEIN; GOPC","url":"https://www.omim.org/entry/606845"},{"mim_id":"606360","title":"WINGLESS-TYPE MMTV INTEGRATION SITE FAMILY, MEMBER 8A; WNT8A","url":"https://www.omim.org/entry/606360"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Endoplasmic reticulum","reliability":"Approved"},{"location":"Primary cilium","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"choroid plexus","ntpm":18.5}],"url":"https://www.proteinatlas.org/search/FZD8"},"hgnc":{"alias_symbol":["FZ-8"],"prev_symbol":[]},"alphafold":{"accession":"Q9H461","domains":[{"cath_id":"1.10.2000.10","chopping":"36-138","consensus_level":"high","plddt":90.8332,"start":36,"end":138},{"cath_id":"1.20.1070.10","chopping":"269-343_384-516_524-610","consensus_level":"high","plddt":90.1656,"start":269,"end":610}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H461","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H461-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H461-F1-predicted_aligned_error_v6.png","plddt_mean":74.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=FZD8","jax_strain_url":"https://www.jax.org/strain/search?query=FZD8"},"sequence":{"accession":"Q9H461","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9H461.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9H461/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H461"}},"corpus_meta":[{"pmid":"25702574","id":"PMC_25702574","title":"Human-chimpanzee differences in a FZD8 enhancer alter cell-cycle dynamics in the developing neocortex.","date":"2015","source":"Current biology : CB","url":"https://pubmed.ncbi.nlm.nih.gov/25702574","citation_count":211,"is_preprint":false},{"pmid":"25320014","id":"PMC_25320014","title":"Targeting the c-Met/FZD8 signaling axis eliminates patient-derived cancer stem-like cells in head and neck squamous carcinomas.","date":"2014","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/25320014","citation_count":83,"is_preprint":false},{"pmid":"26537584","id":"PMC_26537584","title":"MicroRNA-100 suppresses the migration and invasion of breast cancer cells by targeting FZD-8 and inhibiting Wnt/β-catenin signaling pathway.","date":"2015","source":"Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/26537584","citation_count":79,"is_preprint":false},{"pmid":"28602974","id":"PMC_28602974","title":"FZD8, a target of p53, promotes bone metastasis in prostate cancer by activating canonical Wnt/β-catenin signaling.","date":"2017","source":"Cancer letters","url":"https://pubmed.ncbi.nlm.nih.gov/28602974","citation_count":63,"is_preprint":false},{"pmid":"23445611","id":"PMC_23445611","title":"Tumor-initiating cells and FZD8 play a major role in drug resistance in triple-negative breast cancer.","date":"2013","source":"Molecular cancer therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/23445611","citation_count":59,"is_preprint":false},{"pmid":"25619565","id":"PMC_25619565","title":"miR-375 regulates the canonical Wnt pathway through FZD8 silencing in arthritis synovial fibroblasts.","date":"2015","source":"Immunology letters","url":"https://pubmed.ncbi.nlm.nih.gov/25619565","citation_count":47,"is_preprint":false},{"pmid":"31040702","id":"PMC_31040702","title":"miRNA-99b-5p targets FZD8 to inhibit non-small cell lung cancer proliferation, migration and invasion.","date":"2019","source":"OncoTargets and therapy","url":"https://pubmed.ncbi.nlm.nih.gov/31040702","citation_count":27,"is_preprint":false},{"pmid":"29441905","id":"PMC_29441905","title":"MiR-99a inhibits keratinocyte proliferation by targeting Frizzled-5 (FZD5) / FZD8 through β-catenin signaling in psoriasis.","date":"2017","source":"Die Pharmazie","url":"https://pubmed.ncbi.nlm.nih.gov/29441905","citation_count":19,"is_preprint":false},{"pmid":"36336221","id":"PMC_36336221","title":"Huangqin Qingre Qubi Capsule inhibits RA pathology by binding FZD8 and further inhibiting the activity of Wnt/β-catenin signaling pathway.","date":"2022","source":"Journal of ethnopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/36336221","citation_count":18,"is_preprint":false},{"pmid":"35859793","id":"PMC_35859793","title":"Overexpression of miR-100-5p inhibits papillary thyroid cancer progression via targeting FZD8.","date":"2022","source":"Open medicine (Warsaw, Poland)","url":"https://pubmed.ncbi.nlm.nih.gov/35859793","citation_count":15,"is_preprint":false},{"pmid":"36127685","id":"PMC_36127685","title":"MiR-99a alleviates apoptosis and extracellular matrix degradation in experimentally induced spine osteoarthritis by targeting FZD8.","date":"2022","source":"BMC musculoskeletal disorders","url":"https://pubmed.ncbi.nlm.nih.gov/36127685","citation_count":9,"is_preprint":false},{"pmid":"34108309","id":"PMC_34108309","title":"circRPS28 (hsa_circ_0049055) is a novel contributor for papillary thyroid carcinoma by regulating cell growth and motility via functioning as ceRNA for miR-345-5p to regulate frizzled family receptor 8 (FZD8).","date":"2021","source":"Endocrine journal","url":"https://pubmed.ncbi.nlm.nih.gov/34108309","citation_count":8,"is_preprint":false},{"pmid":"38494582","id":"PMC_38494582","title":"CircMCTP2 enhances the progression of bladder cancer by regulating the miR-99a-5p/FZD8 axis.","date":"2024","source":"Journal of the Egyptian National Cancer Institute","url":"https://pubmed.ncbi.nlm.nih.gov/38494582","citation_count":7,"is_preprint":false},{"pmid":"37926311","id":"PMC_37926311","title":"Identification and functional validation of FZD8-specific antibodies.","date":"2023","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/37926311","citation_count":5,"is_preprint":false},{"pmid":"15809770","id":"PMC_15809770","title":"Comparative genomics on Fzd8 orthologs.","date":"2005","source":"Oncology reports","url":"https://pubmed.ncbi.nlm.nih.gov/15809770","citation_count":4,"is_preprint":false},{"pmid":"40083923","id":"PMC_40083923","title":"YBX1-driven TUBB6 upregulation facilitates ocular angiogenesis via WNT3A-FZD8 pathway.","date":"2025","source":"Theranostics","url":"https://pubmed.ncbi.nlm.nih.gov/40083923","citation_count":2,"is_preprint":false},{"pmid":"27062828","id":"PMC_27062828","title":"[Effect of pulchinenoside on FZD8 expression of adjuvant arthritis rats].","date":"2015","source":"Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica","url":"https://pubmed.ncbi.nlm.nih.gov/27062828","citation_count":1,"is_preprint":false},{"pmid":"36720664","id":"PMC_36720664","title":"Overexpressions of RHOA, CSNK1A1, DVL2, FZD8, and LRP5 genes enhance gastric cancer development in the presence of Helicobacter pylori.","date":"2023","source":"Arab journal of gastroenterology : the official publication of the Pan-Arab Association of Gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/36720664","citation_count":1,"is_preprint":false},{"pmid":"40318610","id":"PMC_40318610","title":"USP14 promotes osteoarthritis progression by deubiquitinating FZD8 to activate the Wnt/β-catenin signaling pathway.","date":"2025","source":"Immunobiology","url":"https://pubmed.ncbi.nlm.nih.gov/40318610","citation_count":1,"is_preprint":false},{"pmid":"41274478","id":"PMC_41274478","title":"Demethylase, ALKBH1, regulates osteosarcoma chemosensitivity through FZD8/Wnt/β-catenin signaling pathway in the m7G manner.","date":"2025","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/41274478","citation_count":0,"is_preprint":false},{"pmid":"41740485","id":"PMC_41740485","title":"Impact of coding and non-coding SNPs in the FZD8 gene on structural and functional alterations associated with tumorigenesis: A multi-faceted computational approach.","date":"2026","source":"Computers in biology and medicine","url":"https://pubmed.ncbi.nlm.nih.gov/41740485","citation_count":0,"is_preprint":false},{"pmid":"38803384","id":"PMC_38803384","title":"miRNA-99b-5p Targets FZD8 to Inhibit Non-Small Cell Lung Cancer Proliferation, Migration and Invasion [Retraction].","date":"2024","source":"OncoTargets and therapy","url":"https://pubmed.ncbi.nlm.nih.gov/38803384","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.01.19.633799","title":"The Role Of  <i>Fzd8</i>  For Bone Development And Homeostasis In A Mouse Model Generated By CRISPR/Cas9 Genome Editing","date":"2025-01-19","source":"bioRxiv","url":"https://doi.org/10.1101/2025.01.19.633799","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":14663,"output_tokens":2734,"usd":0.0425,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9972,"output_tokens":3027,"usd":0.062768,"stage2_stop_reason":"end_turn"},"total_usd":0.105268,"stage1_batch_id":"msgbatch_01AsR7g8dGTEiEw9U83bJeWn","stage2_batch_id":"msgbatch_01YV5ZyxtFNUZEjxRcpd9jzb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2015,\n      \"finding\": \"A human-accelerated regulatory enhancer (HARE5) physically contacts the core Fzd8 promoter in the mouse embryonic neocortex (shown by chromosome conformation capture), and transgenic mice expressing Fzd8 under the human HARE5 show accelerated neural progenitor cell cycle and increased brain size compared to mice with the chimpanzee HARE5, demonstrating that enhanced FZD8 expression during corticogenesis alters cell-cycle dynamics of neural progenitor cells.\",\n      \"method\": \"Chromosome conformation capture (3C), transgenic mouse lines (Hs-HARE5::Fzd8 vs Pt-HARE5::Fzd8), cell-cycle analysis, brain size measurement\",\n      \"journal\": \"Current biology : CB\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (3C, transgenic rescue, phenotypic quantification) in a single rigorous study with functional validation\",\n      \"pmids\": [\"25702574\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"FZD8 is essential for the interaction between c-Met and Wnt/β-catenin signaling in head and neck squamous carcinoma stem-like cells (HN-CSC); c-Met inhibition downregulates FZD8 via the ERK/c-Fos cascade, and ectopic FZD8 expression rescues the impaired stem-like phenotype caused by c-Met inhibition.\",\n      \"method\": \"siRNA silencing, ectopic overexpression rescue assay, pharmacologic c-Met inhibition (PF-2341066), sphere formation and tumor initiation assays, mouse xenograft model\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic rescue (FZD8 OE reverses c-Met KD phenotype) plus pharmacologic inhibition, single lab\",\n      \"pmids\": [\"25320014\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Wild-type p53 transcriptionally represses FZD8 by directly binding the FZD8 promoter; FZD8 overexpression activates canonical Wnt/β-catenin signaling and promotes prostate cancer cell migration, invasion, stem cell-like phenotypes in vitro, and bone metastasis in vivo, while FZD8 silencing suppresses these effects.\",\n      \"method\": \"Chromatin immunoprecipitation (ChIP) for p53 at FZD8 promoter, FZD8 overexpression and siRNA knockdown, in vitro migration/invasion assays, in vivo bone metastasis mouse model\",\n      \"journal\": \"Cancer letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP plus loss- and gain-of-function with in vivo validation, single lab\",\n      \"pmids\": [\"28602974\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"FZD8-mediated Wnt signaling contributes to chemotherapy resistance in triple-negative breast cancer; FZD8 is upregulated in residual tumor cells after cisplatin/TRAIL treatment, and siRNA-mediated FZD8 inhibition reduces β-catenin and survivin levels and increases apoptosis in the presence of these agents.\",\n      \"method\": \"Gene expression profiling, siRNA knockdown of FZD8, Western blot (β-catenin, survivin), apoptosis assay, in vivo NOD/SCID xenograft with fluorescent imaging\",\n      \"journal\": \"Molecular cancer therapeutics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with defined molecular readouts (β-catenin, survivin) and in vivo validation, single lab\",\n      \"pmids\": [\"23445611\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"FZD8 is a direct target of miR-375 in fibroblast-like synoviocytes; miR-375 suppresses FZD8 expression and downstream canonical Wnt/β-catenin signaling (validated by firefly luciferase reporter assay), and stabilized β-catenin blocks the effects of miR-375, placing FZD8 upstream of β-catenin in the canonical Wnt pathway in arthritis synoviocytes.\",\n      \"method\": \"Luciferase reporter assay, Western blot, RT-qPCR, RNA interference (β-catenin knockdown), ELISA, ChIP\",\n      \"journal\": \"Immunology letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — luciferase reporter validation plus epistasis (stabilized β-catenin rescue), single lab\",\n      \"pmids\": [\"25619565\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"FZD8-specific antibodies (pF8_AC3 and sF8_AG6) were identified using a synthetic library guided by the structure of the pF8_AC3–FZD8 complex; cell-based assays showed these antibodies selectively block FZD8-mediated Wnt signaling activation.\",\n      \"method\": \"Synthetic antibody library selection, structural determination of pF8_AC3–FZD8 complex, cell-based Wnt signaling reporter assay\",\n      \"journal\": \"International journal of biological macromolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1–2 / Weak — structure-guided antibody identification with cell-based functional validation, single lab, single study\",\n      \"pmids\": [\"37926311\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"USP14 interacts with FZD8 (shown by Co-IP and GST pull-down) and stabilizes FZD8 protein through deubiquitination; USP14 silencing inhibits the Wnt/β-catenin pathway via reduced FZD8 levels, and FZD8 overexpression rescues the cellular effects of USP14 knockdown in IL-1β-treated chondrocytes.\",\n      \"method\": \"Co-immunoprecipitation, GST pull-down, ubiquitination assay, Western blot, siRNA knockdown, overexpression rescue, MTT, EdU, flow cytometry, ELISA\",\n      \"journal\": \"Immunobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal binding assays (Co-IP + GST pull-down) plus ubiquitination assay and genetic rescue, single lab\",\n      \"pmids\": [\"40318610\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ALKBH1 demethylase regulates FZD8 mRNA through m7G methylation, suppressing the FZD8/β-catenin signaling axis; ALKBH1 overexpression reduces FZD8 levels and enhances osteosarcoma chemosensitivity to doxorubicin in vitro and in vivo.\",\n      \"method\": \"RIP sequencing, m7G-MeRIP-qPCR, RIP-qPCR, rescue assays, transcriptome sequencing, in vitro and in vivo functional assays\",\n      \"journal\": \"International journal of biological macromolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — m7G-MeRIP-qPCR and RIP-seq directly link ALKBH1 to FZD8 mRNA modification, with in vivo validation, single lab\",\n      \"pmids\": [\"41274478\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Fzd8 knockout in mice (CRISPR/Cas9) leads to increased osteoclasts and decreased osteoblasts, and is associated with altered expression of Fzd10, Lta, and proteins Itgb3 and RANK, establishing a role for FZD8 in bone remodeling/homeostasis.\",\n      \"method\": \"CRISPR/Cas9 knockout mouse model, histology (osteoclast/osteoblast quantification), RNA-seq (DEG analysis), pathway/gene set enrichment analysis, protein expression analysis\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 2 / Weak — CRISPR KO with defined bone phenotype but single preprint, no replication, mechanistic pathway placement largely inferred from DEG analysis\",\n      \"pmids\": [\"bio_10.1101_2025.01.19.633799\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Comparative genomics established that vertebrate FZD8 orthologs are seven-transmembrane receptors containing a Frizzled (Fz) domain in the N-terminal extracellular region, a leucine zipper motif around the fifth transmembrane domain, a Dishevelled (Dvl)-binding motif in the C-terminal cytoplasmic region, and conserved N-linked glycosylation sites.\",\n      \"method\": \"Bioinformatics/comparative genomics sequence analysis across vertebrate orthologs\",\n      \"journal\": \"Oncology reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Moderate — computational/comparative genomics analysis only, no direct biochemical validation of domain functions\",\n      \"pmids\": [\"15809770\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"FZD8 is a seven-transmembrane Frizzled receptor that acts as a canonical Wnt/β-catenin signaling receptor; its expression is transcriptionally repressed by wild-type p53 and epigenetically regulated by ALKBH1-mediated m7G methylation of its mRNA, while at the protein level it is stabilized by the deubiquitinase USP14; FZD8 mediates downstream Wnt/β-catenin activation to promote cancer cell stemness, migration, invasion, chemoresistance, and bone metastasis, and in neural development its expression level (controlled by a human-accelerated enhancer HARE5) directly sets the pace of neural progenitor cell-cycle progression and neocortical size.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"FZD8 is a seven-transmembrane Frizzled-family receptor that transduces canonical Wnt/\\u03b2-catenin signaling and, through this pathway, governs both neural progenitor proliferation during corticogenesis and pro-malignant cell behavior across multiple cancers [#0, #2]. In neural development, FZD8 expression is set by the human-accelerated enhancer HARE5, which physically contacts the Fzd8 promoter; elevated FZD8 accelerates the neural progenitor cell cycle and increases neocortical size [#0]. In cancer, FZD8 acts upstream of \\u03b2-catenin to drive stem-like phenotypes, migration, invasion, and chemoresistance: it is required for cross-talk between c-Met and Wnt signaling in head and neck squamous carcinoma stem-like cells [#1], promotes prostate cancer migration, invasion, and bone metastasis [#2], and sustains \\u03b2-catenin and survivin to confer chemoresistance in triple-negative breast cancer [#3]. FZD8 abundance is controlled at several layers: it is transcriptionally repressed by wild-type p53 binding its promoter [#2] and by miR-375 targeting its transcript [#4], its mRNA is regulated by ALKBH1-mediated m7G methylation that suppresses the FZD8/\\u03b2-catenin axis [#7], and its protein is stabilized by the deubiquitinase USP14 [#6]. FZD8 also contributes to bone homeostasis, with knockout shifting the balance toward osteoclasts over osteoblasts [#8].\",\n  \"teleology\": [\n    {\n      \"year\": 2005,\n      \"claim\": \"Defined the predicted architecture of FZD8 as a Wnt-receptor-type protein, establishing the structural framework for its receptor function.\",\n      \"evidence\": \"Comparative genomics sequence analysis across vertebrate orthologs identifying an N-terminal Fz domain, leucine zipper, Dvl-binding motif, and glycosylation sites\",\n      \"pmids\": [\"15809770\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Computational prediction only, no biochemical validation of domain functions\", \"Does not demonstrate ligand binding or signaling\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Linked FZD8 to therapy resistance, showing FZD8-driven Wnt signaling protects tumor cells from chemotherapy.\",\n      \"evidence\": \"siRNA knockdown of FZD8 with \\u03b2-catenin/survivin readouts and NOD/SCID xenograft in triple-negative breast cancer\",\n      \"pmids\": [\"23445611\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Ligand and receptor activation mechanism not addressed\", \"Single lab, no direct structural binding data\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Positioned FZD8 as a node connecting c-Met to Wnt/\\u03b2-catenin signaling required for cancer stem-like phenotypes.\",\n      \"evidence\": \"siRNA silencing, ectopic FZD8 rescue of c-Met-inhibited phenotype, pharmacologic c-Met inhibition, and xenografts in head and neck carcinoma stem-like cells\",\n      \"pmids\": [\"25320014\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"ERK/c-Fos to FZD8 transcriptional link inferred, not directly mapped at the promoter\", \"Single lab\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Demonstrated that the level of FZD8 expression directly tunes neural progenitor cell-cycle pace and brain size, revealing a developmental role beyond cancer.\",\n      \"evidence\": \"Chromosome conformation capture plus humanized HARE5::Fzd8 transgenic mice with cell-cycle and brain-size quantification\",\n      \"pmids\": [\"25702574\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream Wnt effectors mediating cell-cycle change in progenitors not dissected\", \"Receptor signaling mechanism inferred from expression dosage\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Identified miR-375 as a post-transcriptional repressor placing FZD8 upstream of \\u03b2-catenin in synoviocytes.\",\n      \"evidence\": \"Luciferase reporter validation of miR-375 targeting plus \\u03b2-catenin epistasis rescue in fibroblast-like synoviocytes\",\n      \"pmids\": [\"25619565\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Effect generality across cell types unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Established direct transcriptional repression of FZD8 by wild-type p53 and tied FZD8 to prostate cancer bone metastasis.\",\n      \"evidence\": \"ChIP of p53 at the FZD8 promoter with gain/loss-of-function and an in vivo bone metastasis model\",\n      \"pmids\": [\"28602974\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking FZD8/Wnt to the metastatic bone niche not resolved\", \"Single lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Provided structure-guided antibodies that selectively block FZD8-mediated Wnt activation, confirming FZD8 as a tractable signaling receptor.\",\n      \"evidence\": \"Synthetic antibody library selection, structure of the pF8_AC3\\u2013FZD8 complex, and cell-based Wnt reporter assays\",\n      \"pmids\": [\"37926311\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional antibody activity shown only in cell-based reporters, not in vivo\", \"Single study\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Defined two additional regulatory layers controlling FZD8 abundance: USP14-mediated deubiquitination stabilizing FZD8 protein and ALKBH1-mediated m7G mRNA methylation suppressing the FZD8/\\u03b2-catenin axis.\",\n      \"evidence\": \"Co-IP/GST pull-down with ubiquitination assays and rescue in chondrocytes; RIP-seq and m7G-MeRIP-qPCR with in vivo doxorubicin chemosensitivity in osteosarcoma\",\n      \"pmids\": [\"40318610\", \"41274478\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct deubiquitination site on FZD8 not mapped\", \"Both findings from single labs in distinct disease contexts\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Implicated FZD8 in bone remodeling, with knockout shifting osteoclast/osteoblast balance.\",\n      \"evidence\": \"CRISPR/Cas9 Fzd8 knockout mouse with histology and RNA-seq DEG analysis (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.01.19.633799\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single preprint, no replication\", \"Pathway placement (Fzd10, RANK, Itgb3) inferred from DEG analysis, not mechanistically validated\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How FZD8 ligand selectivity, co-receptor engagement, and Dishevelled coupling produce context-specific outputs in development versus cancer remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct mapping of which Wnt ligands activate FZD8 in each setting\", \"Mechanism distinguishing developmental cell-cycle control from oncogenic invasion not defined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [0, 2, 5]},\n      {\"term_id\": \"GO:0038024\", \"supporting_discovery_ids\": [5, 9]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [9, 5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 2, 3, 4]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [2, 3, 7]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"USP14\", \"MET\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":3,"faith_total":4,"faith_pct":75.0}}