Search Results (131)

Histone tail phosphorylation has diverse effects on a myriad of cellular processes, including cell division, and is highly conserved throughout eukaryotes. Histone H3 phosphorylation at threonine 3 (H3T3) during mitosis occurs at the inner centromeres and is required for proper biorientation of chromosomes on the mitotic spindle. While H3T3 is also phosphorylated during meiosis, a possible role for this modification has not been tested. Here, we asked if H3T3 phosphorylation is important for meiotic division by quantifying sporulation efficiency and spore viability in Saccharomyces cerevisiae mutants with a T3A amino acid substitution. The T3A substitution resulted in reduced sporulation efficiency and reduced spore viability. Analysis of two other H3 tail mutants, K4A and S10A, revealed different effects on sporulation efficiency and spore viability compared to the T3A mutant, suggesting that these phenotypes may be due to failures in distinct functions. To determine if the spindle checkpoint promotes spore viability of the T3A mutant, the MAD2 gene was deleted. This resulted in a severe reduction in spore viability following meiosis. Altogether, the data reveal an important function for histone H3 threonine 3 that requires monitoring by the spindle checkpoint to ensure successful completion of meiosis. Full article

Flammulina velutipes is a widely cultivated edible mushroom in East Asia, recognized for its nutritional benefits and distinct morphology characterized by a long stipe and a compact, hemispherical pileus. The pileus not only plays a critical biological role in reproduction through spore formation but also serves as a key commercial trait influencing consumer preference and market value. Despite its economic importance, pileus development in F. velutipes is highly sensitive to environmental factors, among which carbon dioxide (CO₂) concentration is particularly influential under indoor cultivation conditions. While previous studies have reported that elevated CO₂ levels can inhibit pileus expansion in other mushroom species, the molecular mechanisms by which CO₂ affects pileus growth in F. velutipes remain poorly understood. In this study, we investigated the impact of CO₂ concentration on pileus morphology and gene expression in F. velutipes by cultivating fruiting bodies under two controlled atmospheric conditions: low (1000 ppm) and high (10,000 ppm) CO₂. Morphometric analysis revealed that elevated CO₂ levels significantly suppressed pileus expansion, reducing the average diameter by more than 50% compared to the low CO₂ condition. To elucidate the underlying genetic response, we conducted RNA sequencing and identified 102 differentially expressed genes (DEGs), with 78 being downregulated under elevated CO₂. Functional enrichment analysis highlighted the involvement of cyclin-dependent protein kinase regulatory pathways in this response. Two cyclin genes were found to be significantly downregulated under elevated CO₂ conditions, and their suppression was validated through quantitative real-time PCR. These genes, possessing conserved cyclin_N domains, are implicated in the regulation of the eukaryotic cell cycle, particularly in mitotic growth. These results indicate that CO₂-induced downregulation of cyclin genes may underlie cell cycle arrest, contributing to inhibited pileus development. This study is the first to provide transcriptomic evidence that elevated CO₂ concentrations specifically repress PHO80-like cyclin genes in F. velutipes, revealing a molecular mechanism by which CO₂ stress inhibits pileus development. These findings suggest that elevated CO₂ triggers a morphogenetic checkpoint by repressing PHO80-like cyclins, thereby modulating cell cycle progression during fruiting body development. This study provides the first evidence of such a transcriptional response in edible mushrooms and offers promising molecular targets for breeding CO₂-resilient strains and optimizing commercial cultivation conditions. Full article

Gleason score (GS) is one of the best predictors of prostate cancer (PCa) aggressiveness; however, its biological features need to be elucidated. This study aimed to explore the biological characteristics of localized/locally advanced PCa stratified using in silico GS analysis. Biological features were analyzed using gene set variation analysis and the xCell algorithm with mRNA expression in two independent public databases: The Cancer Genome Atlas (TCGA) (n = 493; radical prostatectomy cohort) and GSE116918 (n = 248; radiation therapy cohort). GS levels were positively correlated with the activity levels of cell proliferation-related gene sets, including E2F targets, the G2M checkpoint, the mitotic spindle, and MYC targets v1 and v2 in both cohorts. Furthermore, GS levels were positively associated with the activity levels of immune-related gene sets and infiltrating fractions of immune cells, including CD4+ memory T cells, dendritic cells, M1 macrophages, and Th2 cells, in both cohorts. Notably, GS levels were positively associated with the score levels of homologous recombination defects, intratumor heterogeneity, fraction genome alteration, neoantigens, and mutation rates in the TCGA cohort. In conclusion, PCa with high GS levels was associated with cancer cell proliferation, immune cell infiltration, and high mutation rates, which may reflect worse clinical outcomes. Full article

Background: Herbal medicine represents a rich yet complex source of bioactive compounds, offering both therapeutic potential and toxicological risks. Methods: In this study, we systematically evaluated the biological effects of three traditional herbal extracts—Mentha longifolia, Scrophularia orientalis, and Echium biebersteinii—using Caenorhabditis elegans as an in vivo model. Results: All three extracts significantly reduced worm survival, induced larval arrest, and triggered a high incidence of males (HIM) phenotypes, indicative of mitotic failure and meiotic chromosome missegregation. Detailed analysis of germline architecture revealed extract-specific abnormalities, including nuclear disorganization, ectopic crescent-shaped nuclei, altered meiotic progression, and reduced bivalent formation. These defects were accompanied by activation of the DNA damage response, as evidenced by upregulation of checkpoint genes (atm-1, atl-1), increased pCHK-1 foci, and elevated germline apoptosis. LC-MS profiling identified 21 major compounds across the extracts, with four compounds—thymol, carvyl acetate, luteolin-7-O-rutinoside, and menthyl acetate—shared by all three herbs. Among them, thymol and carvyl acetate significantly upregulated DNA damage checkpoint genes and promoted apoptosis, whereas thymol and luteolin-7-O-rutinoside contributed to antioxidant activity. Notably, S. orientalis and E. biebersteinii shared 11 of 14 major constituents (79%), correlating with their similar phenotypic outcomes, while M. longifolia exhibited a more distinct chemical profile, possessing seven unique compounds. Conclusions: These findings highlight the complex biological effects of traditional herbal extracts, demonstrating that both beneficial and harmful outcomes can arise from specific phytochemicals within a mixture. By deconstructing these extracts into their active components, such as thymol, carvyl acetate, and luteolin-7-O-rutinoside, we gain critical insight into the mechanisms driving reproductive toxicity and antioxidant activity. This approach underscores the importance of component-level analysis for accurately assessing the therapeutic value and safety profile of medicinal plants, particularly those used in foods and dietary supplements. Full article

Triple-negative breast cancer (TNBC) is a heterogenous group of breast tumors. This type of breast tumor is relatively difficult to manage, due to the lack of expression of Hormone Receptors (HR) and human epidermal growth factor receptor (HER2). Efforts have been made to understand the factors involved in determining how a triple-negative breast tumor responds to therapy. The standard of treatment in most cases today is a combined modality of immune checkpoint inhibitors (ICIs) and chemotherapy with agents such as anti-mitotic (taxanes) or DNA-damaging agents (alkylating agents, cyclophosphamides, platin salts). In this study, we investigated the predictive and prognostic factors for TNBC, in the neoadjuvant setting; understanding each patient’s response before treatment initiation is crucial to guiding the subsequent approach and finally improving patient outcomes. We focused on tumor-infiltrating lymphocytes at the site of the primary tumor (TILs), circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), the mutational status of protein 53 (p53), and Ki-67, investigating the potential roles of these factors in predicting responses to anti-cancer agents. Full article

WEE1 kinase is a crucial cell cycle regulatory protein that controls the timing of mitotic entry. WEE1, via inhibition of Cyclin-dependent Kinase 1 (CDK1) and Cyclin-dependent Kinase 2 (CDK2), governs the G2-M checkpoint by inhibiting entry into mitosis. The state of balance between WEE family kinases and CDC25C phosphatases restricts CDK1/CycB activity. The WEE kinase family consists of WEE1, PKMYT1, and WEE2 (WEE1B). WEE1 and PKMYT1 regulate entry into mitosis during cell cycle progression, whereas WEE2 governs cell cycle progression during meiosis. Recent studies have identified WEE1 as a potential therapeutic target in several cancers, including therapy-resistant triple-negative breast cancer. Adavosertib’s clinical promise was challenged by inter-individual variations in response and side effects. Because of these promising preclinical outcomes, other WEE1 kinase inhibitors (Azenosertib, SC0191, IMP7068, PD0407824, PD0166285, WEE1-IN-5, Zedoresertib, WEE1-IN-8, and ATRN-1051) are being developed, with several currently being evaluated in clinical trials or as an adjuvant to chemotherapies. Preclinical studies show WEE1 inhibitors induce MHC class 1 antigens and STING when given as combination therapies, suggesting potential additional therapeutic opportunities. Reliable predictors of clinical responses based on mechanistic insights remain an important unmet need. Herein, we review the role of WEE1 inhibition therapy in breast cancer. Full article

Biochanin A, a naturally occurring isoflavone derived from legumes, possesses anti-inflammatory, estrogenic, and anticancer activities. In this study, we investigated the cytotoxic effects and underlying molecular mechanisms of Biochanin A in acute myeloid leukemia (AML) cell lines, U937 and THP-1, using in vitro cytotoxicity assays, RNA sequencing, and bioinformatic analyses. Biochanin A induced dose-dependent apoptosis, as evidenced by caspase-7 activation and PARP1 cleavage. Over-representation analysis (ORA) revealed that differentially expressed genes (DEGs) were significantly enriched in pathways related to inflammatory responses, DNA replication, and cell cycle regulation. Gene set enrichment analysis (GSEA) further confirmed the upregulation of apoptosis- and inflammation-related pathways and the downregulation of MYC targets, cholesterol biosynthesis, and G2/M checkpoint gene sets. RT-qPCR analysis demonstrated that Biochanin A downregulated oncogenes such as RUNX1, BCL2, and MYC while upregulating CHOP (GADD153), CDKN1A (p21), and SQSTM1 (p62), contributing to apoptosis and cell cycle arrest across both cell lines. Notably, Biochanin A downregulated PLK1 and UHRF1 in THP-1 cells, indicating a disruption of mitotic progression and epigenetic regulation. In contrast, in U937 cells, Biochanin A upregulated TXNIP and downregulated CCND2, highlighting the involvement of oxidative stress and G1/S cell cycle arrest. These findings support the potential of Biochanin A as a promising therapeutic candidate for AML through both shared and distinct regulatory pathways. Full article

The conserved and essential Cdc13/CTC1-Stn1-Ten1 telomeric complex (CST) ensures chromosome stability by protecting telomere ends and regulating telomerase accessibility. In a recent study, we uncovered mutants of the S. cerevisiae CST, in which damage was sensed by the two major G2/M spindle checkpoints (one is Bub2-dependent and the other one Mad2-dependent), as well as the major G2/M DNA damage checkpoint (Mec1-dependent). In this study, we found, by fluorescence microscopy, that the stability of the mitotic tubulin spindle was profoundly affected in the best-studied of these mutants, stn1-sz2. Additional data from genetic analyses suggested the potential involvement of Stu1 and Stu2, as well as Slk19, in these defects. Throughout this study, we compared the phenotypes of stn1-sz2 with those of cdc13-1, the best-studied CST mutant, which also serves as a prototype of telomere-damage-characterized CST mutants. We propose that stn1-sz2 represents the prototype of cst mutants characterized by tubulin spindle damage. These newly described phenotypes potentially represent the basis for identifying new functions of the CST telomeric complex. These functions might consist of ensuring correct chromosome segregation through the stabilization of the mitotic spindle. Full article

Studying the cell cycle is essential for understanding the molecular mechanisms that regulate cell division, growth, and differentiation in living organisms. However, mitosis constitutes only a brief phase of the overall cell cycle, making its analysis challenging in asynchronous cell populations due to its transient and dynamic nature. Cell synchronization methods help to enrich populations at specific cell cycle stages, including mitosis, typically by using chemical inhibitors to arrest cells at defined checkpoints. However, many existing protocols rely on combinations of inhibitors that interfere with normal mitotic progression, disrupting dynamics and causing side effects such as chromosome non-disjunction or lagging chromosomes, which limit their applicability. In this study, we present an RO3306 block-and-release strategy to selectively enrich cell populations at defined mitotic stages without compromising cell viability or disrupting their progression to mitotic exit. This approach provides a reliable method for studying mitotic events with high temporal resolution. Furthermore, by preserving mitotic integrity, it offers a valuable framework for investigating the molecular mechanisms of cell division and the processes driving genomic instability in human cells. Full article

Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine skin cancer, driven by either Merkel cell polyomavirus (MCPyV) integration or ultraviolet (UV)-induced mutations. In MCPyV-positive tumors, viral T antigens inactivate tumor suppressors pRb and p53, while virus-negative MCCs harbor UV-induced mutations that activate similar oncogenic pathways. Key signaling cascades, including PI3K/AKT/mTOR and MAPK, support tumor proliferation, survival, and resistance to apoptosis. Histologically, MCC consists of small round blue cells with neuroendocrine features, high mitotic rate, and necrosis. The tumor microenvironment (TME) plays a central role in disease progression and immune escape. It comprises a mix of tumor-associated macrophages, regulatory and cytotoxic T cells, and elevated expression of immune checkpoint molecules such as PD-L1, contributing to an immunosuppressive niche. The extracellular matrix (ECM) within the TME is rich in proteoglycans, collagens, and matrix metalloproteinases (MMPs), facilitating tumor cell adhesion, invasion, and interaction with stromal and immune cells. ECM remodeling and integrin-mediated signaling further promote immune evasion and therapy resistance. Although immune checkpoint inhibitors targeting PD-1/PD-L1 have shown promise in treating MCC, resistance remains a major hurdle. Therapeutic strategies that concurrently target the TME—through inhibition of ECM components, MMPs, or integrin signaling—may enhance immune responses and improve clinical outcomes. Full article

Despite decades of research, cancer continues to be a disease of great concern to millions of people around the world. It has been responsible for a total of 609,820 deaths in the U.S. alone in 2023. Over the years, many drugs have been developed to remove or reduce the disease’s impact, all with varying mechanisms of action and side effects. One class of these drugs is small-molecule mitotic inhibitors. These drugs inhibit cancer cell mitosis or self-replication, impeding cell proliferation and eventually leading to cell death. In this paper, small-molecule mitotic inhibitors are discussed and classified through their discovery, underlying chemistry, and mechanism(s) of action. The binding/inhibition of microtubule-related proteins, DNA damage through the inhibition of Checkpoint Kinase 1 protein, and the inhibition of mitotic kinase proteins are discussed in terms of their anticancer activity to provide an overview of a variety of mitotic inhibitors currently commercially available or under investigation, including those in ongoing clinical trial. Clinical trials for anti-mitotic agents are discussed to track research progress, gauge current understanding, and identify possible future prospects. Additionally, antibody–drug conjugates that use mitotic inhibitors as cytotoxic payloads are discussed as possible ways of administering effective anticancer treatments with minimal toxicity. Full article

The role of p31^Comet in deactivating the spindle assembly checkpoint is well described in the literature; however, the data are all completed using Variant 2 of p31^Comet. p31^Comet is known to be expressed as two different splice variants: Variant 1 and Variant 2. Variant 1 contains an additional 32 N-terminal residues compared to Variant 2. We report that Variant 1 exhibits a reduced ability to bind to MAD2 and thus a reduced ability to induce mitotic progression. Additionally, we show that Variant 1 exhibits reduced stability compared to Variant 2. We further show that Variant 1 is uniquely expressed in the Testes, indicating a potentially unique role of Variant 1 in that organ. Overall, we demonstrate the N-terminus of p31^Comet is capable of modulating p31^Comet activity in mitosis. Full article

Background/Objectives: Cutaneous melanoma (CM) is a highly aggressive malignancy with poor prognosis, necessitating novel biomarkers and therapeutic targets. Centromere protein F (CENPF), a mitotic regulator, has been implicated in tumor progression, but its role in melanoma remains unclear. This study aimed to investigate the clinical significance, biological function, and regulatory mechanisms of CENPF in melanoma. Methods: Public melanoma datasets (GSE46517, GSE3189, and GSE7553) were re-analyzed to identify differentially expressed genes (DEGs). CENPF expression was validated in clinical samples (n = 128), melanoma cell lines, and xenograft models. Functional assays (EdU, CCK-8, colony formation, wound healing, transwell, and flow cytometry) and bioinformatics analyses (GO, KEGG, GSEA, and SCENIC) were performed to assess proliferation, apoptosis, metastasis, and regulatory pathways. In vivo tumorigenesis and metastasis were evaluated in BALB/c nude mice. Results: CENPF was significantly upregulated in melanoma tissues and cell lines compared to controls (p < 0.05). High CENPF expression correlated with advanced Clark level (p = 0.006), ulceration (p = 0.04), and poor overall survival (p = 0.005). Knockdown of CENPF suppressed melanoma cell proliferation, migration, and invasion in vitro, while inducing G2/M phase arrest and apoptosis. In vivo, CENPF silencing reduced tumor growth and lung metastasis. Mechanistically, CENPF was transcriptionally activated by E2F3, and the E2F3-CENPF axis promoted cell cycle progression via G2/M checkpoint activation and P53 pathway suppression. Conclusions: CENPF serves as a prognostic biomarker and therapeutic target in melanoma. Its upregulation drives tumor progression through cell cycle dysregulation and immune evasion, while targeting the E2F3-CENPF axis may offer a novel strategy for melanoma treatment. These findings provide critical insights into melanoma pathogenesis and potential clinical applications. Full article

Pediatric primary brain tumors pose significant therapeutic challenges due to their aggressive nature and the critical environment of the developing brain. Traditional modalities like surgery, chemotherapy, and radiotherapy often achieve limited success in high-grade gliomas and embryonal tumors. Tumor-treating fields (TTfields), a non-invasive therapy delivering alternating electric fields, has emerged as a promising approach to disrupt tumor cell division through mechanisms such as mitotic disruption, DNA damage, and tumor microenvironment modulation. TTfields are thought to selectively target dividing tumor cells while sparing healthy, non-dividing cells. While TTfields therapy is FDA-approved for the management of glioblastoma and other cancers, its application in pediatric brain tumors remains under investigation. Preclinical studies reveal its potential in medulloblastoma and ependymoma models, while observational data suggest its safety and feasibility in children. Current research focuses on optimizing TTfields’ efficacy through advanced technologies, including high-intensity arrays, skull remodeling, and integration with immunotherapies such as immune checkpoint inhibitors. Innovative device-based therapies like magnetic field-based technologies further expand the treatment possibilities. As clinical trials progress, TTfields and related modalities offer hope for addressing unmet needs in pediatric neuro-oncology, especially for tumors in challenging locations. Future directions include biomarker identification, tailored protocols, and novel therapeutic combinations to enhance outcomes in pediatric brain tumor management. Full article

Background: Triple-negative breast cancer (TNBC) is a highly aggressive subtype with limited effective treatments available, including targeted therapies, often leading to poor prognosis. Mitotic checkpoint kinase BUB1 is frequently overexpressed in TNBC and correlates with poor survival outcomes suggesting its potential as a therapeutic target. This study explores the cytotoxicity of TNBC cells to BUB1 inhibition, alone or in combination with radiation and demonstrates that ferroptosis, an iron-dependent form of programmed cell death, has a role. Methods: TNBC cell lines (SUM159, MDA-MB-231, and BT-549) were treated with a BUB1 inhibitor BAY1816032 (BUB1i) alone or in combination with the ferroptosis activator RSL3 with or without 4 Gy irradiation. Cell viability assays were conducted to assess treatment effects, qPCR analyses measured expression of key ferroptosis markers including ACSL4, GPX4, PTGS2, SLC7A11, NCOA4, IREB2, NFS1, and TFRC expression, and TBARS assay measured the lipid peroxidation levels. Ferroptosis specificity was confirmed through co-treatment with the ferroptosis inhibitor Ferrostatin-1 (F-1). Results: In all TNBC cell lines studied, BUB1 inhibition significantly induced ferroptosis, marked by increased expression of ACSL4 and PTGS2, decreased expression of GPX4 and SLC7A11, and increased lipid peroxidation levels. The combination of BUB1i with RSL3 further amplified these ferroptotic markers, suggesting at least an additive effect, which was not present with the combination of BUB1i and radiation. Co-treatment with Ferrostatin-1 reversed the expression of ferroptosis markers, suggesting that BUB1i-mediated cell death may involve ferroptotic signaling in TNBC cell lines. Conclusions: This study demonstrates that BUB1 inhibition may independently induce ferroptosis in TNBC cell lines, which is enhanced when combined with a ferroptosis activator. Further research is warranted to delineate the molecular mechanism of BUB1-mediated ferroptosis in TNBC. Full article