{"gene":"SPC25","run_date":"2026-06-10T07:46:39","timeline":{"discoveries":[{"year":2010,"finding":"SPC25 is a component of the Ndc80 kinetochore complex and is required for chromosome alignment, spindle formation, and proper spindle assembly checkpoint signaling during mouse oocyte meiosis. Overexpression caused meiotic arrest, chromosome misalignment, and spindle disruption; RNAi knockdown caused precocious polar body extrusion and severe chromosome misalignment and aberrant spindle formation.","method":"mRNA injection (overexpression), siRNA knockdown, immunofluorescence localization in mouse oocytes","journal":"Cell cycle (Georgetown, Tex.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean loss- and gain-of-function experiments with defined cellular phenotypes in mouse oocytes, two orthogonal perturbation methods, single lab","pmids":["21084868"],"is_preprint":false},{"year":2022,"finding":"SPC25 promotes HCC metastasis by upregulating ITGB4 (integrin subunit β4), an upstream element of the integrin pathway; ITGB4 upregulation partly reversed the decline in invasion/migration caused by SPC25 silencing, and deleting both SPC25 and ITGB4 decreased phosphorylation of FAK, PI3K, and AKT downstream of integrin signaling.","method":"siRNA knockdown, microarray gene-expression profiling, rescue experiments (ITGB4 overexpression), western blotting, wound-healing and Transwell migration assays, in vivo mouse model","journal":"Oncology reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — epistasis rescue experiments plus in vitro and in vivo functional readouts, single lab, multiple orthogonal methods","pmids":["35293598"],"is_preprint":false},{"year":2022,"finding":"SPC25 promotes DNA damage and activates the DNA-PK/AKT/Notch1 signaling cascade in HCC cells; the NICD/RBP-Jκ complex downstream of Notch1 directly targets SOX2 and NANOG transcriptionally to regulate proliferation and self-renewal (stemness) of HCC cells.","method":"SPC25 knockdown/overexpression in HCC cell lines, signaling pathway analysis by western blot, transcriptional reporter assays","journal":"International journal of biological sciences","confidence":"Low","confidence_rationale":"Tier 3 / Weak — pathway activation inferred from western blot and transcriptional assays in a single lab without reconstitution or direct binding evidence for SPC25 within this pathway","pmids":["36147467"],"is_preprint":false},{"year":2024,"finding":"SPC25 acts as a scaffolding platform that assembles an SPC25/RIOK1/MYH9 trimeric complex; within this complex, RIOK1 phosphorylates MYH9 at Ser1943, causing MYH9 to disengage from the cytoskeleton and accumulate in the nucleus, where it potentiates CTNNB1 transcription and activates Wnt/β-catenin signaling, promoting cancer stem cell phenotypes and platinum resistance in epithelial ovarian cancer.","method":"Co-immunoprecipitation, competitive inhibitory peptide (CBP1) disruption of complex, western blot for phospho-MYH9(Ser1943), nuclear fractionation, in vitro and in vivo functional assays, patient-derived organoids","journal":"Advanced science (Weinheim, Baden-Wurttemberg, Germany)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP establishing trimeric complex, defined phosphorylation site, competitive peptide disruption as orthogonal validation, in vivo and organoid readouts, single lab","pmids":["39488790"],"is_preprint":false},{"year":2024,"finding":"PLEK2 directly interacts with SPC25 (demonstrated by Co-IP), and downregulation of SPC25 similarly impairs lung adenocarcinoma cell proliferation and migration; PLEK2-induced malignant phenotypes require PI3K/AKT signaling activation.","method":"Co-IP assay, gene expression profiling, siRNA knockdown of PLEK2 and SPC25, in vitro proliferation/migration assays, in vivo xenograft","journal":"Cell biology international","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP establishing interaction, functional phenotype confirmed but mechanistic link between SPC25 and PI3K/AKT not directly demonstrated, single lab","pmids":["38894536"],"is_preprint":false},{"year":2025,"finding":"SPC25 interacts with NUF2 (a partner within the NDC80 kinetochore complex), and this interaction is required for NSCLC cell growth, invasion, and glycolysis; NUF2 overexpression abolished the inhibitory effects of SPC25 knockdown.","method":"Co-IP assay, FISH assay, qRT-PCR, western blot, siRNA knockdown, rescue by NUF2 overexpression, in vivo xenograft","journal":"Naunyn-Schmiedeberg's archives of pharmacology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — Co-IP and FISH confirming interaction, epistasis rescue experiment, single lab, no reconstitution","pmids":["39755832"],"is_preprint":false},{"year":2025,"finding":"TFDP1 acts as a transcriptional activator of SPC25 (confirmed by luciferase reporter and ChIP assays); SPC25 represses NK cell anti-tumor function by activating glutamine metabolism in lung adenocarcinoma cells.","method":"ChIP assay, luciferase reporter assay, glutamine metabolism assays, flow cytometry, ELISA, immunofluorescence, siRNA knockdown","journal":"Expert review of clinical immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and dual-luciferase confirm direct transcriptional regulation, functional NK cell killing assays, single lab with two orthogonal methods for the regulatory mechanism","pmids":["40552366"],"is_preprint":false},{"year":2025,"finding":"E2F8 is a transcription factor that directly binds the SPC25 promoter to activate SPC25 expression (confirmed by dual-luciferase and ChIP assays); SPC25 overexpression enhances glutamine metabolism and immune escape in lung adenocarcinoma cells, and E2F8 knockdown-mediated suppression of immune escape is reversed by SPC25 overexpression.","method":"Dual-luciferase reporter assay, ChIP assay, co-culture immunoassay, glutamine metabolism assays (glutamine uptake, glutamate/α-KG levels, NADPH/NADP and GSH/GSSG ratios, SLC1A5 expression), siRNA/overexpression","journal":"Immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and dual-luciferase confirm direct transcriptional activation, epistasis rescue establishes pathway order, single lab with multiple orthogonal methods","pmids":["39829079"],"is_preprint":false},{"year":2025,"finding":"SPC25 inhibits MDM2-mediated ubiquitination of the transcription factor E2F1 by binding MDM2, stabilizing E2F1 protein, which in turn transcriptionally upregulates CCND1 to promote esophageal squamous cell carcinoma progression; CCND1 overexpression counteracted the effects of SPC25 silencing.","method":"Co-immunoprecipitation (SPC25–MDM2 binding), ubiquitination assays, western blot, siRNA knockdown, CCND1 rescue overexpression, in vitro and in vivo functional assays, IHC","journal":"Translational oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP establishing SPC25–MDM2 interaction, ubiquitination assay showing functional consequence, epistasis rescue, single lab","pmids":["39919356"],"is_preprint":false},{"year":2024,"finding":"SPC25 activates the Warburg effect (glycolysis) in prostate cancer cells and thereby suppresses ferroptosis; 2-deoxy-d-glucose (a glycolysis inhibitor) reversed SPC25-mediated suppression of ferroptosis markers, placing SPC25 upstream of glycolysis in the ferroptosis-resistance pathway.","method":"SPC25 overexpression/knockdown, Seahorse XF analyzer (ECAR/OCR), glucose uptake assay, lactate assay, flow cytometry for lipid ROS and Fe2+/MDA content, western blot for ferroptosis markers, 2-DG rescue","journal":"American journal of men's health","confidence":"Low","confidence_rationale":"Tier 3 / Weak — functional metabolic assays with pharmacological rescue, no direct binding or reconstitution for the SPC25–glycolysis link, single lab","pmids":["39558547"],"is_preprint":false}],"current_model":"SPC25 is a core subunit of the NDC80 kinetochore complex (partnering with NDC80, NUF2, and SPC24) that is essential for kinetochore–microtubule attachment, chromosome alignment, and spindle assembly checkpoint signaling during both mitosis and meiosis; beyond this canonical role, SPC25 acts as a scaffolding platform that nucleates multi-protein complexes (e.g., SPC25/RIOK1/MYH9) to activate oncogenic signaling cascades (Wnt/β-catenin, FAK/PI3K/AKT, DNA-PK/AKT/Notch1), modulates protein stability by competing with MDM2-mediated ubiquitination of E2F1, and promotes metabolic reprogramming (glycolysis, glutamine metabolism) to suppress ferroptosis and anti-tumor immunity; its expression is transcriptionally activated by TFDP1 and E2F8 via direct promoter binding."},"narrative":{"mechanistic_narrative":"SPC25 is a core subunit of the NDC80 kinetochore complex that is required for chromosome alignment, spindle formation, and spindle assembly checkpoint signaling, established during mouse oocyte meiosis where both overexpression and knockdown disrupted chromosome alignment and spindle architecture [PMID:21084868]. Within this complex, SPC25 physically engages its kinetochore partner NUF2 [PMID:39755832]. Beyond this canonical mitotic/meiotic role, SPC25 functions as a scaffolding platform in cancer: it nucleates an SPC25/RIOK1/MYH9 trimeric complex in which RIOK1 phosphorylates MYH9 at Ser1943, driving nuclear MYH9 accumulation, CTNNB1 transcription, and Wnt/β-catenin activation that promotes cancer stem cell phenotypes and platinum resistance [PMID:39488790]. SPC25 also stabilizes the transcription factor E2F1 by binding MDM2 and blocking MDM2-mediated E2F1 ubiquitination, leading to CCND1 upregulation and tumor progression [PMID:39919356]. SPC25 promotes metabolic reprogramming, activating glutamine metabolism to enable immune escape from NK cell killing [PMID:40552366, PMID:39829079] and driving glycolysis to suppress ferroptosis [PMID:39558547]. Its expression is directly activated at the promoter level by the transcription factors TFDP1 and E2F8 [PMID:40552366, PMID:39829079].","teleology":[{"year":2010,"claim":"Established SPC25 as a functional component of the NDC80 kinetochore complex by showing it is required for chromosome alignment, spindle formation, and checkpoint signaling, defining its core cell-division role.","evidence":"mRNA overexpression, siRNA knockdown, and immunofluorescence localization in mouse oocytes","pmids":["21084868"],"confidence":"Medium","gaps":["Did not resolve molecular interfaces with other NDC80 subunits in this system","Restricted to meiotic oocytes; mitotic contribution not directly tested here"]},{"year":2022,"claim":"Connected SPC25 to oncogenic integrin signaling, showing it promotes metastasis through ITGB4 and downstream FAK/PI3K/AKT phosphorylation.","evidence":"siRNA knockdown, microarray profiling, ITGB4 rescue, migration assays, and mouse model in HCC","pmids":["35293598"],"confidence":"Medium","gaps":["Mechanism by which SPC25 upregulates ITGB4 not defined","No direct SPC25–integrin physical link shown"]},{"year":2022,"claim":"Linked SPC25 to DNA-PK/AKT/Notch1 signaling and stemness transcription (SOX2, NANOG) in HCC, extending its role to self-renewal control.","evidence":"knockdown/overexpression, western blot, and transcriptional reporter assays in HCC cell lines","pmids":["36147467"],"confidence":"Low","gaps":["No direct binding evidence placing SPC25 in this pathway; activation inferred indirectly","No reconstitution"]},{"year":2024,"claim":"Defined SPC25 as a scaffold that assembles the SPC25/RIOK1/MYH9 complex, mechanistically linking it to Wnt/β-catenin activation and platinum resistance.","evidence":"reciprocal Co-IP, competitive peptide disruption, phospho-MYH9(Ser1943) blotting, nuclear fractionation, organoids and in vivo assays in ovarian cancer","pmids":["39488790"],"confidence":"Medium","gaps":["Structural basis of the trimeric assembly not resolved","Whether scaffolding is independent of kinetochore function unclear"]},{"year":2024,"claim":"Identified PLEK2 as a direct SPC25 interactor and placed SPC25 within PI3K/AKT-dependent lung adenocarcinoma malignancy.","evidence":"single Co-IP, knockdown, proliferation/migration assays, xenograft","pmids":["38894536"],"confidence":"Low","gaps":["Single Co-IP without reciprocal validation","Direct SPC25-to-PI3K/AKT mechanistic link not demonstrated"]},{"year":2024,"claim":"Showed SPC25 drives the Warburg effect to suppress ferroptosis, positioning it upstream of glycolysis in a metabolic survival pathway.","evidence":"overexpression/knockdown, Seahorse, lipid ROS/Fe2+/MDA flow cytometry, 2-DG pharmacological rescue in prostate cancer","pmids":["39558547"],"confidence":"Low","gaps":["No direct binding or reconstitution for the SPC25–glycolysis link","Mechanism of glycolytic activation unknown"]},{"year":2025,"claim":"Demonstrated SPC25–NUF2 physical interaction is required for NSCLC growth, invasion, and glycolysis, reinforcing the functional importance of the kinetochore partnership in cancer.","evidence":"Co-IP, FISH, qRT-PCR, western blot, NUF2 rescue, xenograft","pmids":["39755832"],"confidence":"Low","gaps":["No reconstitution of the interaction","Whether glycolytic effect is a kinetochore-dependent function unclear"]},{"year":2025,"claim":"Established direct transcriptional control of SPC25 by TFDP1 and E2F8 and linked SPC25-driven glutamine metabolism to suppression of NK cell anti-tumor immunity and immune escape.","evidence":"ChIP and dual-luciferase reporter assays, glutamine metabolism assays, NK co-culture/killing assays in lung adenocarcinoma","pmids":["40552366","39829079"],"confidence":"Medium","gaps":["How SPC25 mechanistically activates glutamine metabolism not defined","Relationship between transcriptional regulators not integrated"]},{"year":2025,"claim":"Defined a mechanism by which SPC25 stabilizes E2F1 by binding MDM2 and blocking its ubiquitination, driving CCND1-dependent tumor progression.","evidence":"Co-IP, ubiquitination assays, CCND1 rescue, in vitro/in vivo assays and IHC in esophageal squamous cell carcinoma","pmids":["39919356"],"confidence":"Medium","gaps":["Structural basis of SPC25–MDM2 binding not resolved","Whether SPC25 affects other MDM2 substrates not tested"]},{"year":null,"claim":"How SPC25's canonical kinetochore role mechanistically relates to its diverse scaffolding, protein-stabilization, and metabolic functions in cancer remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model integrating kinetochore versus scaffold functions","Unclear whether oncogenic functions require kinetochore localization","No unifying mechanism connecting the multiple signaling and metabolic outputs"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[3]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[0]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,3]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[6,7,9]}],"complexes":["NDC80 kinetochore complex","SPC25/RIOK1/MYH9 complex"],"partners":["NUF2","RIOK1","MYH9","PLEK2","MDM2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9HBM1","full_name":"Kinetochore protein Spc25","aliases":[],"length_aa":224,"mass_kda":26.2,"function":"Acts as a component of the essential kinetochore-associated NDC80 complex, which is required for chromosome segregation and spindle checkpoint activity (PubMed:14699129, PubMed:14738735). Required for kinetochore integrity and the organization of stable microtubule binding sites in the outer plate of the kinetochore (PubMed:14699129, PubMed:14738735). The NDC80 complex synergistically enhances the affinity of the SKA1 complex for microtubules and may allow the NDC80 complex to track depolymerizing microtubules (PubMed:23085020)","subcellular_location":"Nucleus; Chromosome, centromere, kinetochore","url":"https://www.uniprot.org/uniprotkb/Q9HBM1/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/SPC25","classification":"Common Essential","n_dependent_lines":1206,"n_total_lines":1208,"dependency_fraction":0.9983443708609272},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"MIS12","stoichiometry":10.0},{"gene":"DNAJC7","stoichiometry":0.2},{"gene":"HSPA4","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/SPC25","total_profiled":1310},"omim":[{"mim_id":"619411","title":"SIGNAL PEPTIDASE COMPLEX, SUBUNIT 2; SPCS2","url":"https://www.omim.org/entry/619411"},{"mim_id":"609395","title":"SPC25, NDC80 KINETOCHORE COMPLEX COMPONENT; SPC25","url":"https://www.omim.org/entry/609395"},{"mim_id":"609394","title":"SPC24, NDC80 KINETOCHORE COMPLEX COMPONENT; SPC24","url":"https://www.omim.org/entry/609394"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Cytosol","reliability":"Enhanced"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"lymphoid tissue","ntpm":8.0}],"url":"https://www.proteinatlas.org/search/SPC25"},"hgnc":{"alias_symbol":["MGC22228","AD024"],"prev_symbol":["SPBC25"]},"alphafold":{"accession":"Q9HBM1","domains":[{"cath_id":"3.30.457.50","chopping":"143-222","consensus_level":"high","plddt":89.4019,"start":143,"end":222},{"cath_id":"1.20.5","chopping":"101-137","consensus_level":"medium","plddt":96.1286,"start":101,"end":137}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9HBM1","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9HBM1-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9HBM1-F1-predicted_aligned_error_v6.png","plddt_mean":91.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SPC25","jax_strain_url":"https://www.jax.org/strain/search?query=SPC25"},"sequence":{"accession":"Q9HBM1","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9HBM1.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9HBM1/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9HBM1"}},"corpus_meta":[{"pmid":"21084868","id":"PMC_21084868","title":"Perturbation of Spc25 expression affects meiotic spindle organization, chromosome alignment and spindle assembly checkpoint in mouse oocytes.","date":"2010","source":"Cell cycle (Georgetown, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/21084868","citation_count":54,"is_preprint":false},{"pmid":"31400751","id":"PMC_31400751","title":"Up-regulation of SPC25 promotes breast cancer.","date":"2019","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/31400751","citation_count":31,"is_preprint":false},{"pmid":"35293598","id":"PMC_35293598","title":"SPC25 promotes hepatocellular carcinoma metastasis via activating the FAK/PI3K/AKT signaling pathway through ITGB4.","date":"2022","source":"Oncology reports","url":"https://pubmed.ncbi.nlm.nih.gov/35293598","citation_count":27,"is_preprint":false},{"pmid":"36147467","id":"PMC_36147467","title":"SPC25 promotes proliferation and stemness of hepatocellular carcinoma cells via the DNA-PK/AKT/Notch1 signaling pathway.","date":"2022","source":"International journal of biological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/36147467","citation_count":25,"is_preprint":false},{"pmid":"32351050","id":"PMC_32351050","title":"SPC25 may promote proliferation and metastasis of hepatocellular carcinoma via p53.","date":"2020","source":"FEBS open bio","url":"https://pubmed.ncbi.nlm.nih.gov/32351050","citation_count":15,"is_preprint":false},{"pmid":"39488790","id":"PMC_39488790","title":"Targeting the SPC25/RIOK1/MYH9 Axis to Overcome Tumor Stemness and Platinum Resistance in Epithelial Ovarian Cancer.","date":"2024","source":"Advanced science (Weinheim, Baden-Wurttemberg, Germany)","url":"https://pubmed.ncbi.nlm.nih.gov/39488790","citation_count":12,"is_preprint":false},{"pmid":"35965791","id":"PMC_35965791","title":"The synergistic effect of CDKN2B-AS1 and SPC25 on triple-negative breast cancer.","date":"2022","source":"Annals of translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/35965791","citation_count":11,"is_preprint":false},{"pmid":"38894536","id":"PMC_38894536","title":"PLEK2 activates the PI3K/AKT signaling pathway to drive lung adenocarcinoma progression by upregulating SPC25.","date":"2024","source":"Cell biology international","url":"https://pubmed.ncbi.nlm.nih.gov/38894536","citation_count":11,"is_preprint":false},{"pmid":"34746885","id":"PMC_34746885","title":"CADM1 and SPC25 Gene Mutations in Lung Cancer Patients With Idiopathic Pulmonary Fibrosis.","date":"2021","source":"JTO clinical and research reports","url":"https://pubmed.ncbi.nlm.nih.gov/34746885","citation_count":10,"is_preprint":false},{"pmid":"37872583","id":"PMC_37872583","title":"Psoralen synergizes with exosome-loaded SPC25 to alleviate senescence of nucleus pulposus cells in intervertebral disc degeneration.","date":"2023","source":"Journal of orthopaedic surgery and research","url":"https://pubmed.ncbi.nlm.nih.gov/37872583","citation_count":5,"is_preprint":false},{"pmid":"39755832","id":"PMC_39755832","title":"Berberine restrains non-small cell lung cancer cell growth, invasion and glycolysis via inactivating the SPC25/NUF2 pathway.","date":"2025","source":"Naunyn-Schmiedeberg's archives of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/39755832","citation_count":4,"is_preprint":false},{"pmid":"39558547","id":"PMC_39558547","title":"SPC25 Activates the Warburg Effect to Inhibit Ferroptosis in Prostate Cancer Cells.","date":"2024","source":"American journal of men's health","url":"https://pubmed.ncbi.nlm.nih.gov/39558547","citation_count":4,"is_preprint":false},{"pmid":"40552366","id":"PMC_40552366","title":"TFDP1 activates SPC25-mediated glutamine metabolism to repress anti-tumor immunity of NK cells in lung adenocarcinoma.","date":"2025","source":"Expert review of clinical immunology","url":"https://pubmed.ncbi.nlm.nih.gov/40552366","citation_count":3,"is_preprint":false},{"pmid":"39948743","id":"PMC_39948743","title":"Mefloquine Suppresses Metastasis in Renal Cell Carcinoma Through Targeting SPC25.","date":"2025","source":"Cancer science","url":"https://pubmed.ncbi.nlm.nih.gov/39948743","citation_count":3,"is_preprint":false},{"pmid":"28927328","id":"PMC_28927328","title":"Spc25: How the kinetochore protein plays during oocyte meiosis.","date":"2011","source":"Cell cycle (Georgetown, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/28927328","citation_count":3,"is_preprint":false},{"pmid":"39829079","id":"PMC_39829079","title":"Mechanism Study of E2F8 Activation of SPC25-Mediated Glutamine Metabolism Promoting Immune Escape in Lung Adenocarcinoma.","date":"2025","source":"Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/39829079","citation_count":2,"is_preprint":false},{"pmid":"40400636","id":"PMC_40400636","title":"The multifaceted functions of SPC25 in cancer: from molecular pathways to targeted therapy.","date":"2025","source":"Frontiers in medicine","url":"https://pubmed.ncbi.nlm.nih.gov/40400636","citation_count":2,"is_preprint":false},{"pmid":"39919356","id":"PMC_39919356","title":"SPC25 upregulates CCND1 to promote the progression of esophageal squamous cell carcinoma by inhibiting MDM2-mediated E2F1 ubiquitination.","date":"2025","source":"Translational oncology","url":"https://pubmed.ncbi.nlm.nih.gov/39919356","citation_count":2,"is_preprint":false},{"pmid":"41257451","id":"PMC_41257451","title":"RETRACTION: SPC25 May Promote Proliferation and Metastasis of Hepatocellular Carcinoma via p53.","date":"2025","source":"FEBS open bio","url":"https://pubmed.ncbi.nlm.nih.gov/41257451","citation_count":1,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.08.04.25332945","title":"Proteomic signatures of the <i>APOE ε4</i> and <i>APOE ε2</i> genetic variants and Alzheimer’s disease","date":"2025-08-06","source":"bioRxiv","url":"https://doi.org/10.1101/2025.08.04.25332945","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11585,"output_tokens":2818,"usd":0.038512,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":10181,"output_tokens":3075,"usd":0.06389,"stage2_stop_reason":"end_turn"},"total_usd":0.102402,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"SPC25 is a component of the Ndc80 kinetochore complex and is required for chromosome alignment, spindle formation, and proper spindle assembly checkpoint signaling during mouse oocyte meiosis. Overexpression caused meiotic arrest, chromosome misalignment, and spindle disruption; RNAi knockdown caused precocious polar body extrusion and severe chromosome misalignment and aberrant spindle formation.\",\n      \"method\": \"mRNA injection (overexpression), siRNA knockdown, immunofluorescence localization in mouse oocytes\",\n      \"journal\": \"Cell cycle (Georgetown, Tex.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean loss- and gain-of-function experiments with defined cellular phenotypes in mouse oocytes, two orthogonal perturbation methods, single lab\",\n      \"pmids\": [\"21084868\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"SPC25 promotes HCC metastasis by upregulating ITGB4 (integrin subunit β4), an upstream element of the integrin pathway; ITGB4 upregulation partly reversed the decline in invasion/migration caused by SPC25 silencing, and deleting both SPC25 and ITGB4 decreased phosphorylation of FAK, PI3K, and AKT downstream of integrin signaling.\",\n      \"method\": \"siRNA knockdown, microarray gene-expression profiling, rescue experiments (ITGB4 overexpression), western blotting, wound-healing and Transwell migration assays, in vivo mouse model\",\n      \"journal\": \"Oncology reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis rescue experiments plus in vitro and in vivo functional readouts, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"35293598\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"SPC25 promotes DNA damage and activates the DNA-PK/AKT/Notch1 signaling cascade in HCC cells; the NICD/RBP-Jκ complex downstream of Notch1 directly targets SOX2 and NANOG transcriptionally to regulate proliferation and self-renewal (stemness) of HCC cells.\",\n      \"method\": \"SPC25 knockdown/overexpression in HCC cell lines, signaling pathway analysis by western blot, transcriptional reporter assays\",\n      \"journal\": \"International journal of biological sciences\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — pathway activation inferred from western blot and transcriptional assays in a single lab without reconstitution or direct binding evidence for SPC25 within this pathway\",\n      \"pmids\": [\"36147467\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"SPC25 acts as a scaffolding platform that assembles an SPC25/RIOK1/MYH9 trimeric complex; within this complex, RIOK1 phosphorylates MYH9 at Ser1943, causing MYH9 to disengage from the cytoskeleton and accumulate in the nucleus, where it potentiates CTNNB1 transcription and activates Wnt/β-catenin signaling, promoting cancer stem cell phenotypes and platinum resistance in epithelial ovarian cancer.\",\n      \"method\": \"Co-immunoprecipitation, competitive inhibitory peptide (CBP1) disruption of complex, western blot for phospho-MYH9(Ser1943), nuclear fractionation, in vitro and in vivo functional assays, patient-derived organoids\",\n      \"journal\": \"Advanced science (Weinheim, Baden-Wurttemberg, Germany)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP establishing trimeric complex, defined phosphorylation site, competitive peptide disruption as orthogonal validation, in vivo and organoid readouts, single lab\",\n      \"pmids\": [\"39488790\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PLEK2 directly interacts with SPC25 (demonstrated by Co-IP), and downregulation of SPC25 similarly impairs lung adenocarcinoma cell proliferation and migration; PLEK2-induced malignant phenotypes require PI3K/AKT signaling activation.\",\n      \"method\": \"Co-IP assay, gene expression profiling, siRNA knockdown of PLEK2 and SPC25, in vitro proliferation/migration assays, in vivo xenograft\",\n      \"journal\": \"Cell biology international\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP establishing interaction, functional phenotype confirmed but mechanistic link between SPC25 and PI3K/AKT not directly demonstrated, single lab\",\n      \"pmids\": [\"38894536\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SPC25 interacts with NUF2 (a partner within the NDC80 kinetochore complex), and this interaction is required for NSCLC cell growth, invasion, and glycolysis; NUF2 overexpression abolished the inhibitory effects of SPC25 knockdown.\",\n      \"method\": \"Co-IP assay, FISH assay, qRT-PCR, western blot, siRNA knockdown, rescue by NUF2 overexpression, in vivo xenograft\",\n      \"journal\": \"Naunyn-Schmiedeberg's archives of pharmacology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — Co-IP and FISH confirming interaction, epistasis rescue experiment, single lab, no reconstitution\",\n      \"pmids\": [\"39755832\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TFDP1 acts as a transcriptional activator of SPC25 (confirmed by luciferase reporter and ChIP assays); SPC25 represses NK cell anti-tumor function by activating glutamine metabolism in lung adenocarcinoma cells.\",\n      \"method\": \"ChIP assay, luciferase reporter assay, glutamine metabolism assays, flow cytometry, ELISA, immunofluorescence, siRNA knockdown\",\n      \"journal\": \"Expert review of clinical immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and dual-luciferase confirm direct transcriptional regulation, functional NK cell killing assays, single lab with two orthogonal methods for the regulatory mechanism\",\n      \"pmids\": [\"40552366\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"E2F8 is a transcription factor that directly binds the SPC25 promoter to activate SPC25 expression (confirmed by dual-luciferase and ChIP assays); SPC25 overexpression enhances glutamine metabolism and immune escape in lung adenocarcinoma cells, and E2F8 knockdown-mediated suppression of immune escape is reversed by SPC25 overexpression.\",\n      \"method\": \"Dual-luciferase reporter assay, ChIP assay, co-culture immunoassay, glutamine metabolism assays (glutamine uptake, glutamate/α-KG levels, NADPH/NADP and GSH/GSSG ratios, SLC1A5 expression), siRNA/overexpression\",\n      \"journal\": \"Immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and dual-luciferase confirm direct transcriptional activation, epistasis rescue establishes pathway order, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"39829079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SPC25 inhibits MDM2-mediated ubiquitination of the transcription factor E2F1 by binding MDM2, stabilizing E2F1 protein, which in turn transcriptionally upregulates CCND1 to promote esophageal squamous cell carcinoma progression; CCND1 overexpression counteracted the effects of SPC25 silencing.\",\n      \"method\": \"Co-immunoprecipitation (SPC25–MDM2 binding), ubiquitination assays, western blot, siRNA knockdown, CCND1 rescue overexpression, in vitro and in vivo functional assays, IHC\",\n      \"journal\": \"Translational oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP establishing SPC25–MDM2 interaction, ubiquitination assay showing functional consequence, epistasis rescue, single lab\",\n      \"pmids\": [\"39919356\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"SPC25 activates the Warburg effect (glycolysis) in prostate cancer cells and thereby suppresses ferroptosis; 2-deoxy-d-glucose (a glycolysis inhibitor) reversed SPC25-mediated suppression of ferroptosis markers, placing SPC25 upstream of glycolysis in the ferroptosis-resistance pathway.\",\n      \"method\": \"SPC25 overexpression/knockdown, Seahorse XF analyzer (ECAR/OCR), glucose uptake assay, lactate assay, flow cytometry for lipid ROS and Fe2+/MDA content, western blot for ferroptosis markers, 2-DG rescue\",\n      \"journal\": \"American journal of men's health\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — functional metabolic assays with pharmacological rescue, no direct binding or reconstitution for the SPC25–glycolysis link, single lab\",\n      \"pmids\": [\"39558547\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SPC25 is a core subunit of the NDC80 kinetochore complex (partnering with NDC80, NUF2, and SPC24) that is essential for kinetochore–microtubule attachment, chromosome alignment, and spindle assembly checkpoint signaling during both mitosis and meiosis; beyond this canonical role, SPC25 acts as a scaffolding platform that nucleates multi-protein complexes (e.g., SPC25/RIOK1/MYH9) to activate oncogenic signaling cascades (Wnt/β-catenin, FAK/PI3K/AKT, DNA-PK/AKT/Notch1), modulates protein stability by competing with MDM2-mediated ubiquitination of E2F1, and promotes metabolic reprogramming (glycolysis, glutamine metabolism) to suppress ferroptosis and anti-tumor immunity; its expression is transcriptionally activated by TFDP1 and E2F8 via direct promoter binding.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SPC25 is a core subunit of the NDC80 kinetochore complex that is required for chromosome alignment, spindle formation, and spindle assembly checkpoint signaling, established during mouse oocyte meiosis where both overexpression and knockdown disrupted chromosome alignment and spindle architecture [#0]. Within this complex, SPC25 physically engages its kinetochore partner NUF2 [#5]. Beyond this canonical mitotic/meiotic role, SPC25 functions as a scaffolding platform in cancer: it nucleates an SPC25/RIOK1/MYH9 trimeric complex in which RIOK1 phosphorylates MYH9 at Ser1943, driving nuclear MYH9 accumulation, CTNNB1 transcription, and Wnt/\\u03b2-catenin activation that promotes cancer stem cell phenotypes and platinum resistance [#3]. SPC25 also stabilizes the transcription factor E2F1 by binding MDM2 and blocking MDM2-mediated E2F1 ubiquitination, leading to CCND1 upregulation and tumor progression [#8]. SPC25 promotes metabolic reprogramming, activating glutamine metabolism to enable immune escape from NK cell killing [#6, #7] and driving glycolysis to suppress ferroptosis [#9]. Its expression is directly activated at the promoter level by the transcription factors TFDP1 and E2F8 [#6, #7].\"\n,\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Established SPC25 as a functional component of the NDC80 kinetochore complex by showing it is required for chromosome alignment, spindle formation, and checkpoint signaling, defining its core cell-division role.\",\n      \"evidence\": \"mRNA overexpression, siRNA knockdown, and immunofluorescence localization in mouse oocytes\",\n      \"pmids\": [\"21084868\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not resolve molecular interfaces with other NDC80 subunits in this system\", \"Restricted to meiotic oocytes; mitotic contribution not directly tested here\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Connected SPC25 to oncogenic integrin signaling, showing it promotes metastasis through ITGB4 and downstream FAK/PI3K/AKT phosphorylation.\",\n      \"evidence\": \"siRNA knockdown, microarray profiling, ITGB4 rescue, migration assays, and mouse model in HCC\",\n      \"pmids\": [\"35293598\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which SPC25 upregulates ITGB4 not defined\", \"No direct SPC25\\u2013integrin physical link shown\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Linked SPC25 to DNA-PK/AKT/Notch1 signaling and stemness transcription (SOX2, NANOG) in HCC, extending its role to self-renewal control.\",\n      \"evidence\": \"knockdown/overexpression, western blot, and transcriptional reporter assays in HCC cell lines\",\n      \"pmids\": [\"36147467\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct binding evidence placing SPC25 in this pathway; activation inferred indirectly\", \"No reconstitution\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defined SPC25 as a scaffold that assembles the SPC25/RIOK1/MYH9 complex, mechanistically linking it to Wnt/\\u03b2-catenin activation and platinum resistance.\",\n      \"evidence\": \"reciprocal Co-IP, competitive peptide disruption, phospho-MYH9(Ser1943) blotting, nuclear fractionation, organoids and in vivo assays in ovarian cancer\",\n      \"pmids\": [\"39488790\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of the trimeric assembly not resolved\", \"Whether scaffolding is independent of kinetochore function unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified PLEK2 as a direct SPC25 interactor and placed SPC25 within PI3K/AKT-dependent lung adenocarcinoma malignancy.\",\n      \"evidence\": \"single Co-IP, knockdown, proliferation/migration assays, xenograft\",\n      \"pmids\": [\"38894536\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single Co-IP without reciprocal validation\", \"Direct SPC25-to-PI3K/AKT mechanistic link not demonstrated\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Showed SPC25 drives the Warburg effect to suppress ferroptosis, positioning it upstream of glycolysis in a metabolic survival pathway.\",\n      \"evidence\": \"overexpression/knockdown, Seahorse, lipid ROS/Fe2+/MDA flow cytometry, 2-DG pharmacological rescue in prostate cancer\",\n      \"pmids\": [\"39558547\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct binding or reconstitution for the SPC25\\u2013glycolysis link\", \"Mechanism of glycolytic activation unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Demonstrated SPC25\\u2013NUF2 physical interaction is required for NSCLC growth, invasion, and glycolysis, reinforcing the functional importance of the kinetochore partnership in cancer.\",\n      \"evidence\": \"Co-IP, FISH, qRT-PCR, western blot, NUF2 rescue, xenograft\",\n      \"pmids\": [\"39755832\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No reconstitution of the interaction\", \"Whether glycolytic effect is a kinetochore-dependent function unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Established direct transcriptional control of SPC25 by TFDP1 and E2F8 and linked SPC25-driven glutamine metabolism to suppression of NK cell anti-tumor immunity and immune escape.\",\n      \"evidence\": \"ChIP and dual-luciferase reporter assays, glutamine metabolism assays, NK co-culture/killing assays in lung adenocarcinoma\",\n      \"pmids\": [\"40552366\", \"39829079\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How SPC25 mechanistically activates glutamine metabolism not defined\", \"Relationship between transcriptional regulators not integrated\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Defined a mechanism by which SPC25 stabilizes E2F1 by binding MDM2 and blocking its ubiquitination, driving CCND1-dependent tumor progression.\",\n      \"evidence\": \"Co-IP, ubiquitination assays, CCND1 rescue, in vitro/in vivo assays and IHC in esophageal squamous cell carcinoma\",\n      \"pmids\": [\"39919356\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of SPC25\\u2013MDM2 binding not resolved\", \"Whether SPC25 affects other MDM2 substrates not tested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How SPC25's canonical kinetochore role mechanistically relates to its diverse scaffolding, protein-stabilization, and metabolic functions in cancer remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model integrating kinetochore versus scaffold functions\", \"Unclear whether oncogenic functions require kinetochore localization\", \"No unifying mechanism connecting the multiple signaling and metabolic outputs\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 3]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [6, 7, 9]}\n    ],\n    \"complexes\": [\"NDC80 kinetochore complex\", \"SPC25/RIOK1/MYH9 complex\"],\n    \"partners\": [\"NUF2\", \"RIOK1\", \"MYH9\", \"PLEK2\", \"MDM2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":6,"faith_total":6,"faith_pct":100.0}}