Bladder cancer (BC) is the most common urinary tract malignancy. Aurora kinase B (AURKB), a component of the chromosomal passenger protein complex, affects chromosomal segregation during cell division. Mitotic arrest-deficient 2-like protein 2 (MAD2L2) interacts with various proteins and contributes to genomic integrity. Both AURKB and MAD2L2 are overexpressed in various human cancers and have synergistic oncogenic effects; therefore, they are regarded as emerging therapeutic targets for cancer. However, the relationship between these factors and the mechanisms underlying their oncogenic activity in BC remains largely unknown. The present study aimed to explore the interactions between AURKB and MAD2L2 and how they affect BC progression via the DNA damage response (DDR) pathway.
Bioinformatics was used to analyze the expression, prognostic value, and pro-tumoral function of AURKB in patients with BC. CCK-8 assay, colony-forming assay, flow cytometry, SA-β-gal staining, wound healing assay, and transwell chamber experiments were performed to test the viability, cell cycle progression, senescence, and migration and invasion abilities of BC cells in vitro. A nude mouse xenograft assay was performed to test the tumorigenesis ability of BC cells in vivo. The expression and interaction of proteins and the occurrence of the senescence-associated secretory phenotype were detected using western blot analysis, co-immunoprecipitation assay, and RT-qPCR.
AURKB was highly expressed and associated with prognosis in patients with BC. AURKB expression was positively correlated with MAD2L2 expression. We confirmed that AURKB interacts with, and modulates the expression of, MAD2L2 in BC cells. AURKB knockdown suppressed the proliferation, migration, and invasion abilities of, and cell cycle progression in, BC cells, inducing senescence in these cells. The effects of AURKB knockdown were rescued by MAD2L2 overexpression in vitro and in vivo. The effects of MAD2L2 knockdown were similar to those of AURKB knockdown. Furthermore, p53 ablation rescued the MAD2L2 knockdown-induced suppression of BC cell proliferation and cell cycle arrest and senescence in BC cells.
AURKB activates MAD2L2 expression to downregulate the p53 DDR pathway, thereby promoting BC progression. Thus, AURKB may serve as a potential molecular marker and a novel anticancer therapeutic target for BC.

Ovarian cancer (OVCA), a prevalent gynecological malignancy, ranks as the fourth most common cancer among women. Mitotic Arrest Deficient 2 Like 2 (MAD2L2), a chromatin-binding protein and a component of DNA polymerase ζ, has been previously identified as an inhibitor of tumor growth in colorectal cancer. However, the roles of MAD2L2 in OVCA, including its expression, impact, and prognostic significance, remain unclear. We employed bioinformatics tools, Cox Regression analysis, and in vitro cell experiments to investigate its biological functions. Our findings reveal that MAD2L2 typically undergoes genomic alterations, such as amplifications and deep deletions. Moreover, we observed an overexpression of MAD2L2 mRNA in OVCA patients, correlating with reduced survival rates, particularly in those with Grade IV tumors. Furthermore, analysis of mRNA biofunctions indicated that MAD2L2 is predominantly localized in the organellar ribosome, engaging mainly in NADH dehydrogenase activity. This was deduced from the results of gene ontology enrichment analysis, which also identified its role as a structural constituent in mitochondrial translation elongation. These findings were corroborated by KEGG pathway analysis, further revealing MAD2L2\'s involvement in tumor metabolism and the cell death process. Notably, MAD2L2 protein expression showed significant associations with various immune cells, including CD4+T cells, CD8+T cells, B cells, natural killer cells, and Myeloid dendritic cells. Additionally, elevated levels of MAD2L2 were found to enhance cell proliferation and migration in OVCA cells. The upregulation of MAD2L2 also appears to inhibit the ferroptosis process, coinciding with increased mTOR signaling activity in these cells. Our study identifies MAD2L2 as a novel regulator in ovarian tumor progression and offers new insights for treating OVCA.

BACKGROUND: Hepatocellular carcinoma (HCC) is a major health concern, necessitating a deeper understanding of its prognosis and underlying mechanisms. This study aimed to investigate the mechanism and prognostic value of CD8+ T Cell exhaustion (CD8+ TEX)-related genes in HCC and construct a survival prognosis prediction model for patients with HCC.
METHODS: CD8+ TEX-related genes associated with HCC prognosis were analysed and identified, and a prognostic prediction model was constructed using the \'least absolute shrinkage and selection operator\' Cox regression model. Immunohistochemistry was used to verify the expression of the model genes in HCC tissues. A nomogram was constructed based on risk scores and clinical features, and its predictive efficacy was verified. The expression of STAM, ANXA5, and MAD2L2 in HCC cell lines was detected by western blotting; subsequently, these genes were knocked down in HCC cell lines by small interfering RNA, and their effects on the proliferation and migration of HCC cell lines were detected by colony formation assay, cck8, wound healing, and transwell assays.
RESULTS: Six genes related to CD8+ TEX were included in the risk-prediction model. The prognosis of patients with HCC in the low-risk group was significantly better than that of those in the high-risk group. Cox regression analysis revealed that the risk score was an independent risk factor for the prognosis of patients with HCC. The differentially expressed genes in patients with high-risk HCC were mainly enriched in the nucleotide-binding oligomerization domain-containing protein-like receptor, hypoxia-inducible factor-1, and tumour programmed cell death protein (PD)-1/PD-L1 immune checkpoint pathways. The CD8+ TEX-related genes STAM, ANXA5, and MAD2L2 were knocked down in HCC cell lines to significantly inhibit cell proliferation and migration. The prediction results of the nomogram based on the risk score showed a good fit and application value.
CONCLUSIONS: The prediction model based on CD8+ TEX-related genes can predict the prognosis of HCC and provide a theoretical basis for the early identification of patients with poor HCC prognosis.

Glioblastoma, the most common primary malignant tumor of the brain, is associated with poor prognosis. Glioblastoma cells exhibit high proliferative and invasive properties, and glioblastoma stem cells (GSCs) have been shown to play a crucial role in the malignant behavior of glioblastoma cells. This study aims to investigate the molecular mechanisms involved in GSCs maintenance and malignant progression.
Bioinformatics analysis was performed based on data from public databases to explore the expression profile of Mitotic arrest deficient 2 like 2 (MAD2L2) and its potential function in glioma. The impact of MAD2L2 on glioblastoma cell behaviors was assessed through cell viability assays (CCK8), colony formation assays, 5-Ethynyl-2\'-deoxyuridine (EDU) incorporation assays, scratch assays, and transwell migration/invasion assays. The findings from in vitro experiments were further validated in vivo using xenograft tumor model. GSCs were isolated from the U87 and LN229 cell lines through flow cytometry and the stemness characteristics were verified by immunofluorescence staining. The sphere-forming ability of GSCs was examined using the stem cell sphere formation assay. Bioinformatics methods were conducted to identified the potential downstream target genes of MAD2L2, followed by in vitro experimental validation. Furthermore, potential upstream transcription factors that regulate MAD2L2 expression were confirmed through chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays.
The MAD2L2 exhibited high expression in glioblastoma samples and showed significant correlation with patient prognosis. In vitro and in vivo experiments confirmed that silencing of MAD2L2 led to decreased proliferation, invasion, and migration capabilities of glioblastoma cells, while decreasing stemness characteristics of glioblastoma stem cells. Conversely, overexpression of MAD2L2 enhanced these malignant behaviors. Further investigation revealed that MYC proto-oncogene (c-MYC) mediated the functional role of MAD2L2 in glioblastoma, which was further validated through a rescue experiment. Moreover, using dual-luciferase reporter gene assays and ChIP assays determined that the upstream transcription factor E2F-1 regulated the expression of MAD2L2.
Our study elucidated the role of MAD2L2 in maintaining glioblastoma stemness and promoting malignant behaviors through the regulation of c-MYC, suggesting its potential as a therapeutic target.

Insulin activates insulin receptor (IR) signaling and subsequently triggers IR endocytosis to attenuate signaling. Cell division regulators MAD2, BUBR1, and p31comet promote IR endocytosis on insulin stimulation. Here, we show that genetic ablation of the IR-MAD2 interaction in mice delays IR endocytosis, increases IR levels, and prolongs insulin action at the cell surface. This in turn causes a defect in insulin clearance and increases circulating insulin levels, unexpectedly increasing glucagon levels, which alters glucose metabolism modestly. Disruption of the IR-MAD2 interaction increases serum fatty acid concentrations and hepatic fat accumulation in fasted male mice. Furthermore, disruption of the IR-MAD2 interaction distinctly changes metabolic and transcriptomic profiles in the liver and adipose tissues. Our findings establish the function of cell division regulators in insulin signaling and provide insights into the metabolic functions of IR endocytosis.
UNASSIGNED: The physiological role of IR endocytosis in insulin sensitivity remains unclear. Disruption of the IR-MAD2 interaction delays IR endocytosis and prolongs insulin signaling. IR-MAD2 controls insulin clearance and glucose metabolism. IR-MAD2 maintains energy homeostasis.

Aortic dissection (AD) is a life-threatening condition in which the inner layer of the aorta tears. It has been reported that metabolic syndrome (MS) has a close linkage with aortic dissection. However, the inter-relational mechanisms between them were still unclear. This article explored the hub gene signatures and potential molecular mechanisms in AD and MS. We obtained five bulk RNA-seq datasets of AD, one single cell RNA-seq (scRNA-seq) dataset of ascending thoracic aortic aneurysm (ATAA), and one bulk RNA-seq dataset of MS from the gene expression omnibus (GEO) database. Identification of differentially expressed genes (DEGs) and key modules via weighted gene co-expression network analysis (WGCNA), functional enrichment analysis, and machine learning algorithms (Random Forest and LASSO regression) were used to identify hub genes for diagnosing AD with MS. XGBoost further improved the diagnostic performance of the model. The receiver operating characteristic (ROC) and precision-recall (PR) curves were developed to assess the diagnostic value. Then, immune cell infiltration and metabolism-associated pathways analyses were created to investigate immune cell and metabolism-associated pathway dysregulation in AD and MS. Finally, the scRNA-seq dataset was performed to confirm the expression levels of identified hub genes. 406 common DEGs were identified between the merged AD and MS datasets. Functional enrichment analysis revealed these DEGs were enriched for applicable terms of metabolism, cellular processes, organismal systems, and human diseases. Besides, the positively related key modules of AD and MS were mainly enriched in transcription factor binding and inflammatory response. In contrast, the negatively related modules were significantly associated with adaptive immune response and regulation of nuclease activity. Through machine learning, nine genes with common diagnostic effects were found in AD and MS, including MAD2L2, IMP4, PRPF4, CHSY1, SLC20A1, SLC9A1, TIPRL, DPYD, and MAPKAPK2. In the training set, the AUC of the hub gene on RP and RR curves was 1. In the AD verification set, the AUC of the Hub gene on RP and RR curves were 0.946 and 0.955, respectively. In the MS set, the AUC of the Hub gene on RP and RR curves were 0.978 and 0.98, respectively. scRNA-seq analysis revealed that the SLC20A1 was found to be relevant in fatty acid metabolic pathways and expressed in endothelial cells. Our study revealed the common pathogenesis of AD and MS. These common pathways and hub genes might provide new ideas for further mechanism research.

Accurate chromosome segregation, monitored by the spindle assembly checkpoint (SAC), is crucial for the production of euploid cells. Previous in vitro studies by us and others showed that Mad2, a core member of the SAC, performs a checkpoint function in oocyte meiosis. Here, through an oocyte-specific knockout approach in mouse, we reconfirmed that Mad2-deficient oocytes exhibit an accelerated metaphase-to-anaphase transition caused by premature degradation of securin and cyclin B1 and subsequent activation of separase in meiosis I. However, it was surprising that the knockout mice were completely fertile and the resulting oocytes were euploid. In the absence of Mad2, other SAC proteins, including BubR1, Bub3 and Mad1, were normally recruited to the kinetochores, which likely explains the balanced chromosome separation. Further studies showed that the chromosome separation in Mad2-null oocytes was particularly sensitive to environmental changes and, when matured in vitro, showed chromosome misalignment, lagging chromosomes, and aneuploidy with premature separation of sister chromatids, which was exacerbated at a lower temperature. We reveal for the first time that Mad2 is dispensable for proper chromosome segregation but acts to mitigate environmental stress in meiotic oocytes.

MAD2 is a spindle assembly checkpoint protein that participates in the formation of mitotic checkpoint complex, which blocks mitotic progression. RNF8, an established DNA damage response protein, has been implicated in mitotic checkpoint regulation but its exact role remains poorly understood. Here, RNF8 proximity proteomics uncovered a role of RNF8-MAD2 in generating the mitotic checkpoint signal. Specifically, RNF8 competes with a small pool of p31comet for binding to the closed conformer of MAD2 via its RING domain, while CAMK2D serves as a molecular scaffold to concentrate the RNF8-MAD2 complex via transient/weak interactions between its p-Thr287 and RNF8\'s FHA domain. Accordingly, RNF8 overexpression impairs glioma stem cell (GSC) mitotic progression in a FHA- and RING-dependent manner. Importantly, low RNF8 expression correlates with inferior glioma outcome and RNF8 overexpression impedes GSC tumorigenicity. Last, we identify PLK1 inhibitor that mimics RNF8 overexpression using a chemical biology approach, and demonstrate a PLK1/HSP90 inhibitor combination that synergistically reduces GSC proliferation and stemness. Thus, our study has unveiled a previously unrecognized CAMK2D-RNF8-MAD2 complex in regulating mitotic checkpoint with relevance to gliomas, which is therapeutically targetable.

We previously identified a cell cycle-dependent periodic subcellular distribution of cancer metastasis-associated antigen 1 (MTA1) and unraveled a novel role of MTA1 in inhibiting spindle damage-induced spindle assembly checkpoint (SAC) activation in cancer cells. However, the more detailed subcellular localization of MTA1 in mitotic cells and its copartner in SAC regulation in cancer cells are still poorly understood. Here, through immunofluorescent colocalization analysis of MTA1 and alpha-tubulin in mitotic cancer cells, we reveal that MTA1 is dynamically localized to the spindle apparatus throughout the entire mitotic process. We also demonstrated a reversible upregulation of MTA1 expression upon spindle damage-induced SAC activation, and time-lapse imaging assays indicated that MTA1 silencing delayed the mitotic metaphase-anaphase transition in cancer cells. Further investigation revealed that MTA1 interacts and colocalizes with Translocated Promoter Region (TPR) on spindle microtubules in mitotic cells, and this interaction is attenuated on SAC activation. TPR is well-implicated in SAC regulation via binding the MAD1-MAD2 complex, however, no interactions between MTA1 and MAD1 or MAD2 were detected in our coimmunoprecipitation (co-IP) assays, suggesting that the MTA1-TPR may represent a distinct SAC-associated complex separate from the previously reported TPR-MAD1/MAD2 complex. Our data provide new insights into the subcellular localization and molecular function of MTA1 in SAC regulation in cancer, and indicate that intervention of the MTA1-TPR interaction may be effective to modulate SAC and hence chromosomal instability (CIN) in tumorigenesis.

Human oocyte maturation arrest represents one of the severe conditions for female patients with primary infertility. However, the genetic factors underlying this human disease remain largely unknown. The spindle assembly checkpoint (SAC) is an intricate surveillance mechanism that ensures accurate segregation of chromosomes throughout cell cycles. Once the kinetochores of chromosomes are correctly attached to bipolar spindles and the SAC is satisfied, the MAD2L1BP, best known as p31comet, binds mitosis arrest deficient 2 (MAD2) and recruits the AAA+-ATPase TRIP13 to disassemble the mitotic checkpoint complex (MCC), leading to the cell-cycle progression. In this study, by whole-exome sequencing (WES), we identified homozygous and compound heterozygous MAD2L1BP variants in three families with female patients diagnosed with primary infertility owing to oocyte metaphase I (MI) arrest. Functional studies revealed that the protein variants resulting from the C-terminal truncation of MAD2L1BP lost their binding ability to MAD2. cRNA microinjection of full-length or truncated MAD2L1BP uncovered their discordant roles in driving the extrusion of polar body 1 (PB1) in mouse oocytes. Furthermore, the patient\'s oocytes carrying the mutated MAD2L1BP resumed polar body extrusion (PBE) when rescued by microinjection of full-length MAD2L1BP cRNAs. Together, our studies identified and characterized novel biallelic variants in MAD2L1BP responsible for human oocyte maturation arrest at MI, and thus prompted new therapeutic avenues for curing female primary infertility.