{"gene":"FZD8","run_date":"2026-04-28T17:46:04","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 chimpanzee HARE5::Fzd8 mice, establishing that HARE5-driven FZD8 expression regulates cell-cycle dynamics during corticogenesis.","method":"Chromosome conformation capture (3C), transgenic mouse generation, cell-cycle analysis","journal":"Current biology : CB","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (3C, transgenics, cell-cycle assay) with direct functional readout; highly cited foundational study","pmids":["25702574"],"is_preprint":false},{"year":2014,"finding":"In head and neck squamous carcinoma stem-like cells, c-Met upregulates FZD8 expression through the ERK/c-Fos cascade; FZD8 is required for c-Met to activate Wnt/β-catenin signaling, and ectopic FZD8 expression rescues impaired CSC phenotypes when c-Met is inhibited, placing FZD8 downstream of c-Met and upstream of β-catenin.","method":"siRNA knockdown, ectopic overexpression rescue, pharmacologic inhibition, xenograft model","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 — clean KD/KO with rescue and pathway placement, single lab","pmids":["25320014"],"is_preprint":false},{"year":2017,"finding":"Wild-type p53 transcriptionally represses FZD8 by directly binding the FZD8 promoter (shown by ChIP); FZD8 overexpression promotes prostate cancer cell migration, invasion, and stem cell-like properties through activation of canonical Wnt/β-catenin signaling, and FZD8 silencing suppresses bone metastasis in vivo.","method":"ChIP assay, overexpression/silencing, in vivo bone metastasis model","journal":"Cancer letters","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP demonstrates direct p53–FZD8 promoter interaction; functional phenotype validated in vivo; single lab","pmids":["28602974"],"is_preprint":false},{"year":2013,"finding":"FZD8 mediates Wnt/β-catenin signaling in triple-negative breast cancer tumor-initiating cells; siRNA-mediated FZD8 inhibition in the presence of cisplatin plus TRAIL reduced β-catenin and survivin levels and increased apoptosis, while FZD8 expression was enriched in residual tumors after chemotherapy, linking FZD8-driven Wnt signaling to chemoresistance.","method":"siRNA knockdown, Western blot, in vivo xenograft fluorescence imaging, immunostaining","journal":"Molecular cancer therapeutics","confidence":"Medium","confidence_rationale":"Tier 2 — KD with defined molecular and cellular phenotype, in vivo validation; single lab","pmids":["23445611"],"is_preprint":false},{"year":2015,"finding":"miR-100 directly targets FZD8 (validated by luciferase reporter assay) and its overexpression decreases FZD8 protein and downstream Wnt/β-catenin components (β-catenin, MMP-7, TCF-4, LEF-1), suppressing breast cancer cell migration and invasion.","method":"Luciferase reporter assay, Western blot, migration/invasion assays","journal":"Tumour biology","confidence":"Medium","confidence_rationale":"Tier 3 — luciferase validation of miRNA–FZD8 targeting with functional cellular phenotype; single lab","pmids":["26537584"],"is_preprint":false},{"year":2015,"finding":"miR-375 directly targets FZD8 in arthritis synovial fibroblasts (validated by firefly luciferase reporter assay); FZD8 activates canonical Wnt/β-catenin signaling, and miR-375-mediated suppression of FZD8 reduces MMP3 and fibronectin levels; stabilized β-catenin blocks miR-375 effects.","method":"Luciferase reporter assay, ChIP, Western blot, siRNA, ELISA","journal":"Immunology letters","confidence":"Medium","confidence_rationale":"Tier 2/3 — luciferase validation plus ChIP and epistasis (β-catenin rescue); single lab","pmids":["25619565"],"is_preprint":false},{"year":2023,"finding":"An FZD8-specific antibody (sF8_AG6) was identified using a synthetic library guided by the structure of the pF8_AC3–FZD8 complex; cell-based assays confirmed that these antibodies selectively block FZD8-mediated Wnt signaling activation.","method":"Structural determination of antibody–FZD8 complex, cell-based Wnt signaling assays","journal":"International journal of biological macromolecules","confidence":"Medium","confidence_rationale":"Tier 1/2 — structure-guided antibody design with functional cell-based validation; single lab","pmids":["37926311"],"is_preprint":false},{"year":2025,"finding":"USP14 interacts with FZD8 (Co-IP and GST pull-down) and stabilizes FZD8 protein through deubiquitination; USP14 knockdown reduces FZD8 levels and inhibits Wnt/β-catenin signaling, while FZD8 overexpression rescues the effects of USP14 silencing on chondrocyte apoptosis, inflammation, and ECM degradation.","method":"Co-immunoprecipitation, GST pull-down, ubiquitination assay, overexpression rescue","journal":"Immunobiology","confidence":"Medium","confidence_rationale":"Tier 2 — reciprocal binding assays plus ubiquitination assay and rescue; single lab","pmids":["40318610"],"is_preprint":false},{"year":2025,"finding":"ALKBH1, an m7G demethylase, regulates FZD8 mRNA through m7G methylation (validated by RIP-qPCR and m7G-MeRIP-qPCR); ALKBH1 overexpression suppresses FZD8/β-catenin signaling and enhances osteosarcoma chemosensitivity, while rescue of FZD8 reverses ALKBH1's effects.","method":"RIP-qPCR, m7G-MeRIP-qPCR, transcriptome sequencing, rescue assays, in vivo experiments","journal":"International journal of biological macromolecules","confidence":"Medium","confidence_rationale":"Tier 2 — m7G modification mapped to FZD8 mRNA with rescue and in vivo validation; single lab","pmids":["41274478"],"is_preprint":false},{"year":2025,"finding":"In an Fzd8-knockout mouse model generated by CRISPR/Cas9, homozygous Fzd8 knockout leads to increased osteoclasts and reduced osteoblasts, with altered expression of Fzd10, Lta, Itgb3, and RANK proteins, establishing a role for FZD8 in bone remodeling homeostasis.","method":"CRISPR/Cas9 knockout mouse model, histology, protein expression analysis","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 2 method but preprint, no peer review, single lab","pmids":["bio_10.1101_2025.01.19.633799"],"is_preprint":true},{"year":2025,"finding":"TUBB6 silencing suppresses WNT3A and FZD8 expression downstream, inhibiting WNT/β-catenin signaling and reducing ocular angiogenesis in OIR and CNV models, placing FZD8 as a downstream mediator in the YBX1-TUBB6-WNT3A/FZD8 sprouting angiogenesis pathway.","method":"Transcriptome analysis, TUBB6 KO in vitro and in vivo, tube formation assay, immunofluorescence","journal":"Theranostics","confidence":"Low","confidence_rationale":"Tier 3 — FZD8 identified as downstream target by expression analysis after TUBB6 KO; no direct FZD8 manipulation","pmids":["40083923"],"is_preprint":false}],"current_model":"FZD8 is a seven-transmembrane Frizzled receptor that functions as a canonical Wnt/β-catenin signaling receptor: its expression is transcriptionally repressed by p53 and regulated by an accelerated enhancer (HARE5) that drives neural progenitor cell-cycle progression; FZD8 protein stability is controlled by the deubiquitinase USP14 and its mRNA is regulated by ALKBH1-mediated m7G methylation; in cancer and inflammatory contexts, FZD8 acts downstream of c-Met (via ERK/c-Fos) to sustain β-catenin signaling, and is directly targeted and suppressed by multiple miRNAs (miR-100, miR-375, miR-99a/b, miR-345-5p), with loss of FZD8 consistently dampening Wnt/β-catenin output and related oncogenic or inflammatory phenotypes."},"narrative":{"teleology":[{"year":2013,"claim":"Establishing that FZD8 is a functionally relevant Wnt receptor in cancer stem-like cells: FZD8 knockdown in triple-negative breast cancer tumor-initiating cells reduced β-catenin and survivin levels, linking FZD8-driven Wnt signaling to chemoresistance.","evidence":"siRNA knockdown with Western blot and in vivo xenograft imaging in TNBC cells","pmids":["23445611"],"confidence":"Medium","gaps":["No structural basis for FZD8–Wnt ligand selectivity determined","Contribution of other Frizzled receptors in the same cells not ruled out"]},{"year":2014,"claim":"Placing FZD8 within a defined upstream signaling cascade: c-Met was shown to upregulate FZD8 via ERK/c-Fos, and FZD8 overexpression rescued β-catenin signaling when c-Met was inhibited, establishing a linear c-Met→ERK→c-Fos→FZD8→β-catenin pathway.","evidence":"siRNA/pharmacologic inhibition with ectopic FZD8 rescue in HNSCC cancer stem-like cells and xenografts","pmids":["25320014"],"confidence":"Medium","gaps":["Whether c-Fos directly binds the FZD8 promoter was not shown by ChIP","Generalizability beyond HNSCC stem cells unknown"]},{"year":2015,"claim":"Demonstrating that a human-accelerated enhancer (HARE5) physically contacts the FZD8 promoter and that its human-specific sequence accelerates neural progenitor cell cycle and increases brain size, linking FZD8 expression regulation to human cortical evolution.","evidence":"Chromosome conformation capture (3C) in mouse embryonic neocortex plus transgenic mice comparing human vs. chimpanzee HARE5-driven Fzd8 expression","pmids":["25702574"],"confidence":"High","gaps":["Which Wnt ligands are relevant in the developing neocortex not identified","Downstream effectors beyond β-catenin not dissected"]},{"year":2015,"claim":"Identifying miRNA-mediated post-transcriptional regulation of FZD8: miR-100 and miR-375 were validated as direct FZD8 3′-UTR targeting miRNAs that suppress Wnt/β-catenin output in breast cancer and synovial fibroblasts, respectively.","evidence":"Luciferase reporter assays, Western blot, migration/invasion assays (miR-100 in breast cancer); luciferase reporter plus stabilized β-catenin epistasis (miR-375 in arthritis fibroblasts)","pmids":["26537584","25619565"],"confidence":"Medium","gaps":["Physiological miRNA levels and relevance in vivo not established","Cooperative or redundant miRNA targeting of FZD8 not tested"]},{"year":2017,"claim":"Revealing transcriptional repression of FZD8 by p53: ChIP demonstrated direct p53 binding to the FZD8 promoter, and FZD8 overexpression promoted prostate cancer invasion and bone metastasis through Wnt/β-catenin, linking loss of p53 tumor suppression to FZD8 derepression.","evidence":"ChIP assay, overexpression/silencing, in vivo bone metastasis model in prostate cancer cells","pmids":["28602974"],"confidence":"Medium","gaps":["Whether p53 mutations found in patient tumors correlate with FZD8 upregulation not shown","Specific p53 response element in FZD8 promoter not mapped"]},{"year":2023,"claim":"Developing FZD8-selective blocking tools: structure-guided design of an FZD8-specific antibody (sF8_AG6) demonstrated that FZD8-mediated Wnt signaling can be selectively inhibited at the receptor level.","evidence":"Structural determination of antibody–FZD8 CRD complex and cell-based Wnt reporter assays","pmids":["37926311"],"confidence":"Medium","gaps":["In vivo efficacy of the blocking antibody not tested","Whether antibody discriminates FZD8 from FZD5 in physiological contexts unknown"]},{"year":2025,"claim":"Defining post-translational and epitranscriptomic control of FZD8 protein and mRNA: USP14 was shown to deubiquitinate and stabilize FZD8 protein, while ALKBH1-mediated m7G demethylation of FZD8 mRNA suppresses its expression, each with rescue experiments confirming FZD8 as the critical effector of Wnt/β-catenin output.","evidence":"Co-IP, GST pull-down, ubiquitination assay with rescue (USP14–FZD8); RIP-qPCR, m7G-MeRIP-qPCR with transcriptome sequencing and in vivo rescue (ALKBH1–FZD8)","pmids":["40318610","41274478"],"confidence":"Medium","gaps":["Specific ubiquitin linkage type on FZD8 not determined","Whether m7G methylation affects FZD8 mRNA stability vs. translation not distinguished","Each interaction demonstrated by a single laboratory"]},{"year":null,"claim":"The identity of preferred Wnt ligand(s) for FZD8 in physiological contexts, the co-receptor requirements (e.g., LRP5/6 dependency), and the structural basis for ligand-induced FZD8 activation remain incompletely resolved in the primary literature.","evidence":"","pmids":[],"confidence":"High","gaps":["No Wnt ligand selectivity profiling for FZD8 in the discovery timeline","Co-receptor dependency not directly tested","Full-length FZD8 structure in active/inactive conformations unavailable"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[0,1,3,5]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[6,7]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,2,3,4,5,7,8]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0]}],"complexes":[],"partners":["USP14","ALKBH1","CTNNB1","MET"],"other_free_text":[]},"mechanistic_narrative":"FZD8 is a seven-transmembrane Frizzled family receptor that transduces canonical Wnt/β-catenin signaling in diverse developmental and disease contexts, including corticogenesis, bone remodeling, cancer stem cell maintenance, and inflammatory joint disease. A human-accelerated regulatory enhancer (HARE5) contacts the FZD8 promoter and drives accelerated neural progenitor cell-cycle kinetics during neocortical development, while p53 directly binds the FZD8 promoter to repress its transcription [PMID:25702574, PMID:28602974]. FZD8 protein stability is regulated by USP14-mediated deubiquitination, and FZD8 mRNA levels are controlled by ALKBH1-dependent m7G methylation as well as by multiple miRNAs (miR-100, miR-375) that directly target the FZD8 3′-UTR to attenuate downstream β-catenin, survivin, and TCF/LEF output [PMID:40318610, PMID:41274478, PMID:26537584, PMID:25619565]. In cancer, FZD8 operates downstream of c-Met/ERK/c-Fos signaling to sustain Wnt/β-catenin activation, promoting chemoresistance, invasion, and metastasis in breast, prostate, and head-and-neck carcinomas [PMID:25320014, PMID:23445611]."},"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":205,"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":17,"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":7,"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":6,"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":"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":"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":"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":"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":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":"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":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":13886,"output_tokens":2742,"usd":0.041394},"stage2":{"model":"claude-opus-4-6","input_tokens":6139,"output_tokens":2249,"usd":0.13038},"total_usd":0.171774,"stage1_batch_id":"msgbatch_0118RScg3WGaGkaZRtWZbtce","stage2_batch_id":"msgbatch_01Cpfzvtbj42aqp5oYZ5Te2s","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 chimpanzee HARE5::Fzd8 mice, establishing that HARE5-driven FZD8 expression regulates cell-cycle dynamics during corticogenesis.\",\n      \"method\": \"Chromosome conformation capture (3C), transgenic mouse generation, cell-cycle analysis\",\n      \"journal\": \"Current biology : CB\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (3C, transgenics, cell-cycle assay) with direct functional readout; highly cited foundational study\",\n      \"pmids\": [\"25702574\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"In head and neck squamous carcinoma stem-like cells, c-Met upregulates FZD8 expression through the ERK/c-Fos cascade; FZD8 is required for c-Met to activate Wnt/β-catenin signaling, and ectopic FZD8 expression rescues impaired CSC phenotypes when c-Met is inhibited, placing FZD8 downstream of c-Met and upstream of β-catenin.\",\n      \"method\": \"siRNA knockdown, ectopic overexpression rescue, pharmacologic inhibition, xenograft model\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean KD/KO with rescue and pathway placement, 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 (shown by ChIP); FZD8 overexpression promotes prostate cancer cell migration, invasion, and stem cell-like properties through activation of canonical Wnt/β-catenin signaling, and FZD8 silencing suppresses bone metastasis in vivo.\",\n      \"method\": \"ChIP assay, overexpression/silencing, in vivo bone metastasis model\",\n      \"journal\": \"Cancer letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP demonstrates direct p53–FZD8 promoter interaction; functional phenotype validated in vivo; single lab\",\n      \"pmids\": [\"28602974\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"FZD8 mediates Wnt/β-catenin signaling in triple-negative breast cancer tumor-initiating cells; siRNA-mediated FZD8 inhibition in the presence of cisplatin plus TRAIL reduced β-catenin and survivin levels and increased apoptosis, while FZD8 expression was enriched in residual tumors after chemotherapy, linking FZD8-driven Wnt signaling to chemoresistance.\",\n      \"method\": \"siRNA knockdown, Western blot, in vivo xenograft fluorescence imaging, immunostaining\",\n      \"journal\": \"Molecular cancer therapeutics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KD with defined molecular and cellular phenotype, in vivo validation; single lab\",\n      \"pmids\": [\"23445611\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"miR-100 directly targets FZD8 (validated by luciferase reporter assay) and its overexpression decreases FZD8 protein and downstream Wnt/β-catenin components (β-catenin, MMP-7, TCF-4, LEF-1), suppressing breast cancer cell migration and invasion.\",\n      \"method\": \"Luciferase reporter assay, Western blot, migration/invasion assays\",\n      \"journal\": \"Tumour biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — luciferase validation of miRNA–FZD8 targeting with functional cellular phenotype; single lab\",\n      \"pmids\": [\"26537584\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"miR-375 directly targets FZD8 in arthritis synovial fibroblasts (validated by firefly luciferase reporter assay); FZD8 activates canonical Wnt/β-catenin signaling, and miR-375-mediated suppression of FZD8 reduces MMP3 and fibronectin levels; stabilized β-catenin blocks miR-375 effects.\",\n      \"method\": \"Luciferase reporter assay, ChIP, Western blot, siRNA, ELISA\",\n      \"journal\": \"Immunology letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2/3 — luciferase validation plus ChIP and epistasis (β-catenin rescue); single lab\",\n      \"pmids\": [\"25619565\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"An FZD8-specific antibody (sF8_AG6) was identified using a synthetic library guided by the structure of the pF8_AC3–FZD8 complex; cell-based assays confirmed that these antibodies selectively block FZD8-mediated Wnt signaling activation.\",\n      \"method\": \"Structural determination of antibody–FZD8 complex, cell-based Wnt signaling assays\",\n      \"journal\": \"International journal of biological macromolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1/2 — structure-guided antibody design with functional cell-based validation; single lab\",\n      \"pmids\": [\"37926311\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"USP14 interacts with FZD8 (Co-IP and GST pull-down) and stabilizes FZD8 protein through deubiquitination; USP14 knockdown reduces FZD8 levels and inhibits Wnt/β-catenin signaling, while FZD8 overexpression rescues the effects of USP14 silencing on chondrocyte apoptosis, inflammation, and ECM degradation.\",\n      \"method\": \"Co-immunoprecipitation, GST pull-down, ubiquitination assay, overexpression rescue\",\n      \"journal\": \"Immunobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal binding assays plus ubiquitination assay and rescue; single lab\",\n      \"pmids\": [\"40318610\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ALKBH1, an m7G demethylase, regulates FZD8 mRNA through m7G methylation (validated by RIP-qPCR and m7G-MeRIP-qPCR); ALKBH1 overexpression suppresses FZD8/β-catenin signaling and enhances osteosarcoma chemosensitivity, while rescue of FZD8 reverses ALKBH1's effects.\",\n      \"method\": \"RIP-qPCR, m7G-MeRIP-qPCR, transcriptome sequencing, rescue assays, in vivo experiments\",\n      \"journal\": \"International journal of biological macromolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — m7G modification mapped to FZD8 mRNA with rescue and in vivo validation; single lab\",\n      \"pmids\": [\"41274478\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In an Fzd8-knockout mouse model generated by CRISPR/Cas9, homozygous Fzd8 knockout leads to increased osteoclasts and reduced osteoblasts, with altered expression of Fzd10, Lta, Itgb3, and RANK proteins, establishing a role for FZD8 in bone remodeling homeostasis.\",\n      \"method\": \"CRISPR/Cas9 knockout mouse model, histology, protein expression analysis\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 2 method but preprint, no peer review, single lab\",\n      \"pmids\": [\"bio_10.1101_2025.01.19.633799\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TUBB6 silencing suppresses WNT3A and FZD8 expression downstream, inhibiting WNT/β-catenin signaling and reducing ocular angiogenesis in OIR and CNV models, placing FZD8 as a downstream mediator in the YBX1-TUBB6-WNT3A/FZD8 sprouting angiogenesis pathway.\",\n      \"method\": \"Transcriptome analysis, TUBB6 KO in vitro and in vivo, tube formation assay, immunofluorescence\",\n      \"journal\": \"Theranostics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — FZD8 identified as downstream target by expression analysis after TUBB6 KO; no direct FZD8 manipulation\",\n      \"pmids\": [\"40083923\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"FZD8 is a seven-transmembrane Frizzled receptor that functions as a canonical Wnt/β-catenin signaling receptor: its expression is transcriptionally repressed by p53 and regulated by an accelerated enhancer (HARE5) that drives neural progenitor cell-cycle progression; FZD8 protein stability is controlled by the deubiquitinase USP14 and its mRNA is regulated by ALKBH1-mediated m7G methylation; in cancer and inflammatory contexts, FZD8 acts downstream of c-Met (via ERK/c-Fos) to sustain β-catenin signaling, and is directly targeted and suppressed by multiple miRNAs (miR-100, miR-375, miR-99a/b, miR-345-5p), with loss of FZD8 consistently dampening Wnt/β-catenin output and related oncogenic or inflammatory phenotypes.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"FZD8 is a seven-transmembrane Frizzled family receptor that transduces canonical Wnt/β-catenin signaling in diverse developmental and disease contexts, including corticogenesis, bone remodeling, cancer stem cell maintenance, and inflammatory joint disease. A human-accelerated regulatory enhancer (HARE5) contacts the FZD8 promoter and drives accelerated neural progenitor cell-cycle kinetics during neocortical development, while p53 directly binds the FZD8 promoter to repress its transcription [PMID:25702574, PMID:28602974]. FZD8 protein stability is regulated by USP14-mediated deubiquitination, and FZD8 mRNA levels are controlled by ALKBH1-dependent m7G methylation as well as by multiple miRNAs (miR-100, miR-375) that directly target the FZD8 3′-UTR to attenuate downstream β-catenin, survivin, and TCF/LEF output [PMID:40318610, PMID:41274478, PMID:26537584, PMID:25619565]. In cancer, FZD8 operates downstream of c-Met/ERK/c-Fos signaling to sustain Wnt/β-catenin activation, promoting chemoresistance, invasion, and metastasis in breast, prostate, and head-and-neck carcinomas [PMID:25320014, PMID:23445611].\",\n  \"teleology\": [\n    {\n      \"year\": 2013,\n      \"claim\": \"Establishing that FZD8 is a functionally relevant Wnt receptor in cancer stem-like cells: FZD8 knockdown in triple-negative breast cancer tumor-initiating cells reduced β-catenin and survivin levels, linking FZD8-driven Wnt signaling to chemoresistance.\",\n      \"evidence\": \"siRNA knockdown with Western blot and in vivo xenograft imaging in TNBC cells\",\n      \"pmids\": [\"23445611\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural basis for FZD8–Wnt ligand selectivity determined\", \"Contribution of other Frizzled receptors in the same cells not ruled out\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Placing FZD8 within a defined upstream signaling cascade: c-Met was shown to upregulate FZD8 via ERK/c-Fos, and FZD8 overexpression rescued β-catenin signaling when c-Met was inhibited, establishing a linear c-Met→ERK→c-Fos→FZD8→β-catenin pathway.\",\n      \"evidence\": \"siRNA/pharmacologic inhibition with ectopic FZD8 rescue in HNSCC cancer stem-like cells and xenografts\",\n      \"pmids\": [\"25320014\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether c-Fos directly binds the FZD8 promoter was not shown by ChIP\", \"Generalizability beyond HNSCC stem cells unknown\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Demonstrating that a human-accelerated enhancer (HARE5) physically contacts the FZD8 promoter and that its human-specific sequence accelerates neural progenitor cell cycle and increases brain size, linking FZD8 expression regulation to human cortical evolution.\",\n      \"evidence\": \"Chromosome conformation capture (3C) in mouse embryonic neocortex plus transgenic mice comparing human vs. chimpanzee HARE5-driven Fzd8 expression\",\n      \"pmids\": [\"25702574\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which Wnt ligands are relevant in the developing neocortex not identified\", \"Downstream effectors beyond β-catenin not dissected\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Identifying miRNA-mediated post-transcriptional regulation of FZD8: miR-100 and miR-375 were validated as direct FZD8 3′-UTR targeting miRNAs that suppress Wnt/β-catenin output in breast cancer and synovial fibroblasts, respectively.\",\n      \"evidence\": \"Luciferase reporter assays, Western blot, migration/invasion assays (miR-100 in breast cancer); luciferase reporter plus stabilized β-catenin epistasis (miR-375 in arthritis fibroblasts)\",\n      \"pmids\": [\"26537584\", \"25619565\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological miRNA levels and relevance in vivo not established\", \"Cooperative or redundant miRNA targeting of FZD8 not tested\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Revealing transcriptional repression of FZD8 by p53: ChIP demonstrated direct p53 binding to the FZD8 promoter, and FZD8 overexpression promoted prostate cancer invasion and bone metastasis through Wnt/β-catenin, linking loss of p53 tumor suppression to FZD8 derepression.\",\n      \"evidence\": \"ChIP assay, overexpression/silencing, in vivo bone metastasis model in prostate cancer cells\",\n      \"pmids\": [\"28602974\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether p53 mutations found in patient tumors correlate with FZD8 upregulation not shown\", \"Specific p53 response element in FZD8 promoter not mapped\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Developing FZD8-selective blocking tools: structure-guided design of an FZD8-specific antibody (sF8_AG6) demonstrated that FZD8-mediated Wnt signaling can be selectively inhibited at the receptor level.\",\n      \"evidence\": \"Structural determination of antibody–FZD8 CRD complex and cell-based Wnt reporter assays\",\n      \"pmids\": [\"37926311\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo efficacy of the blocking antibody not tested\", \"Whether antibody discriminates FZD8 from FZD5 in physiological contexts unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Defining post-translational and epitranscriptomic control of FZD8 protein and mRNA: USP14 was shown to deubiquitinate and stabilize FZD8 protein, while ALKBH1-mediated m7G demethylation of FZD8 mRNA suppresses its expression, each with rescue experiments confirming FZD8 as the critical effector of Wnt/β-catenin output.\",\n      \"evidence\": \"Co-IP, GST pull-down, ubiquitination assay with rescue (USP14–FZD8); RIP-qPCR, m7G-MeRIP-qPCR with transcriptome sequencing and in vivo rescue (ALKBH1–FZD8)\",\n      \"pmids\": [\"40318610\", \"41274478\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific ubiquitin linkage type on FZD8 not determined\", \"Whether m7G methylation affects FZD8 mRNA stability vs. translation not distinguished\", \"Each interaction demonstrated by a single laboratory\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The identity of preferred Wnt ligand(s) for FZD8 in physiological contexts, the co-receptor requirements (e.g., LRP5/6 dependency), and the structural basis for ligand-induced FZD8 activation remain incompletely resolved in the primary literature.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No Wnt ligand selectivity profiling for FZD8 in the discovery timeline\", \"Co-receptor dependency not directly tested\", \"Full-length FZD8 structure in active/inactive conformations unavailable\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [0, 1, 3, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [6, 7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 2, 3, 4, 5, 7, 8]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"USP14\",\n      \"ALKBH1\",\n      \"CTNNB1\",\n      \"MET\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}