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Depletion interactions are thought to significantly contribute to the organization of intracellular structures in the crowded cytosol. The strength of depletion interactions depends on physical parameters such as the depletant number density and the depletant size ratio. Cells are known to dynamically regulate these two parameters by varying the copy number of proteins of a wide distribution of sizes. However, mammalian cells are also known to keep the total protein mass density remarkably constant, to within 0.5% throughout the cell cycle. We thus ask how the strength of depletion interactions varies when the total depletant mass is held fixed, a.k.a. fixed-mass depletion. We answer this question via scaling arguments, as well as by studying depletion effects on networks of reconstituted semiflexible actin in silico and in vitro. We examine the maximum strength of the depletion interaction potential U∗ as a function of q, the size ratio between the depletant and the matter being depleted. We uncover a scaling relation U∗ ∼ qζ for two cases: fixed volume fraction φ and fixed mass density ρ. For fixed volume fraction, we report ζ < 0. For the fixed mass density case, we report ζ > 0, which suggests that the depletion interaction strength increases as the depletant size ratio is increased. To test this prediction, we prepared our filament networks at fixed mass concentrations with varying sizes of the depletant molecule poly(ethylene glycol) (PEG). We characterize the depletion interaction strength in our simulations via the mesh size. In experiments, we observe two distinct actin network morphologies, which we call weakly bundled and strongly bundled. We identify a mass concentration where different PEG depletant sizes lead to weakly bundled or strongly bundled morphologies. For these conditions, we find that the mesh size and intra-bundle spacing between filaments across the different morphologies do not show significant differences, while the dynamic light scattering relaxation time and storage modulus between the two states do show significant differences. Our results demonstrate the ability to tune actin network morphology and mechanics by controlling depletant size and give insights into depletion interaction mechanisms under the fixed-depletant-mass constraint relevant to living cells. [ABSTRACT FROM AUTHOR]

Active loop extrusion—the process of formation of dynamically growing chromatin loops due to the motor activity of DNA–binding protein complexes—is a firmly established mechanism responsible for chromatin spatial organization at different stages of a cell cycle in eukaryotes and bacteria. The theoretical insight into the effect of loop extrusion on the experimentally measured statistics of chromatin conformation can be gained with an appropriately chosen polymer model. Here, we consider the simplest analytically solvable model of an interphase chromosome, which is treated as an ideal chain with disorder of sufficiently sparse random loops whose conformations are sampled from the equilibrium ensemble. This framework allows us to arrive at the closed-form analytical expression for the mean-squared distance between pairs of genomic loci, which is valid beyond the one-loop approximation in diagrammatic representation. In addition, we analyze the loop-induced deviation of chain conformations from the Gaussian statistics by calculating kurtosis of probability density of the pairwise separation vector. The presented results suggest the possible ways of estimating the characteristics of the loop extrusion process based on the experimental data on the scale-dependent statistics of intra-chromosomal pair-wise distances. [ABSTRACT FROM AUTHOR]

We studied the D3-type cyclin function during gynoecium development in Arabidopsis and how they are related to the hormone cytokinin and the transcription factor SPATULA. Growth throughout the life of plants is sustained by cell division and differentiation processes in meristematic tissues. In Arabidopsis, gynoecium development implies a multiphasic process where the tissues required for pollination, fertilization, and seed development form. The Carpel Margin Meristem (CMM) is a mass of undifferentiated cells that gives rise to the gynoecium internal tissues, such as septum, ovules, placenta, funiculus, transmitting tract, style, and stigma. Different genetic and hormonal factors, including cytokinin, control the CMM function. Cytokinin regulates the cell cycle transitions through the activation of cell cycle regulators as cyclin genes. D3-type cyclins are expressed in proliferative tissues, favoring the mitotic cell cycle over the endoreduplication. Though the role of cytokinin in CMM and gynoecium development is highly studied, its specific role in regulating the cell cycle in this tissue remains unclear. Additionally, despite extensive research on the relationship between CYCD3 genes and cytokinin, the regulatory mechanism that connects them remains elusive. Here, we found that D3-type cyclins are expressed in proliferative medial and lateral tissues. Conversely, the depletion of the three CYCD3 genes showed that they are not essential for gynoecium development. However, the addition of exogenous cytokinin showed that they could control the division/differentiation balance in gynoecium internal tissues and outgrowths. Finally, we found that SPATULA can be a mechanistic link between cytokinin and the D3-type cyclins. The data suggest that the role of D3-type cyclins in gynoecium development is related to the cytokinin response, and they might be activated by the transcription factor SPATULA.

Mutations in human nonsense-mediated mRNA decay (NMD) factors are enriched in neurodevelopmental disorders. We show that deletion of key NMD factor Upf2 in mouse embryonic neural progenitor cells causes perinatal microcephaly but deletion in immature neurons does not, indicating NMD's critical roles in progenitors. Upf2 knockout (KO) prolongs the cell cycle of radial glia progenitor cells, promotes their transition into intermediate progenitors, and leads to reduced upper-layer neurons. CRISPRi screening identified Trp53 knockdown rescuing Upf2KO progenitors without globally reversing NMD inhibition, implying marginal contributions of most NMD targets to the cell cycle defect. Integrated functional genomics shows that NMD degrades selective TRP53 downstream targets, including Cdkn1a, which, without NMD suppression, slow the cell cycle. Trp53KO restores the progenitor cell pool and rescues the microcephaly of Upf2KO mice. Therefore, one physiological role of NMD in the developing brain is to degrade selective TRP53 targets to control progenitor cell cycle and brain size.

The endoplasmic reticulum (ER) is a single-copy organelle that cannot be generated de novo, suggesting coordination between the mechanisms overseeing ER integrity and those controlling the cell cycle to maintain organelle inheritance. The Unfolded Protein Response (UPR) is a conserved signaling network that regulates ER homeostasis. Here, we show that pharmacological and genetic inhibition of the UPR sensors IRE1, ATF6, and PERK in unstressed cells delays the cell cycle, with PERK inhibition showing the most penetrant effect, which was associated with a slowdown of the G1-to-S/G2 transition. Treatment with the small molecule ISRIB to bypass the effects of PERK-dependent phosphorylation of the translation initiation factor eIF2α had no such effect, suggesting that cell cycle timing depends on PERKs kinase activity but is independent of eIF2α phosphorylation. Using complementary light and electron microscopy and flow cytometry-based analyses, we also demonstrate that the ER enlarges before mitosis. Together, our results suggest coordination between UPR signaling and the cell cycle to maintain ER physiology during cell division.

Entry into the cell cycle in late G1 phase occurs only when sufficient growth has occurred. In budding yeast, a cyclin called Cln3 is thought to link cell-cycle entry to cell growth. Cln3 accumulates during growth in early G1 phase and eventually helps trigger expression of late G1 phase cyclins that drive cell-cycle entry. All current models for cell-cycle entry assume that expression of late G1 phase cyclins is initiated at the transcriptional level. Current models also assume that the sole function of Cln3 in cell-cycle entry is to promote transcription of late G1 phase cyclins, and that Cln3 works solely in G1 phase. Here, we show that cell cycle-dependent expression of the late G1 phase cyclin Cln2 does not require any functions of the CLN2 promoter. Moreover, Cln3 can influence accumulation of Cln2 protein via posttranscriptional mechanisms. Finally, we show that Cln3 has functions in mitosis that strongly influence cell size. Together, these discoveries reveal the existence of surprising new mechanisms that challenge current models for control of cell-cycle entry and cell size.

BACKGROUND: A traditional view is that stem cells (SCs) divide slowly. Meanwhile, both embryonic and pluripotent SCs display a shorter cell cycle duration (CCD) in comparison to more committed progenitors (CPs). METHODS: We examined the in vitro proliferation and cycling behavior of somatic adult human cells using live cell imaging of passage zero keratinocytes and single-cell RNA sequencing. RESULTS: We found two populations of keratinocytes: those with short CCD and protracted near exponential growth, and those with long CCD and terminal differentiation. Applying the ergodic principle, the comparative numbers of cycling cells in S phase in an enriched population of SCs confirmed a shorter CCD than CPs. Further, analysis of single-cell RNA sequencing of cycling adult human keratinocyte SCs and CPs indicated a shortening of both G1 and G2M phases in the SC. CONCLUSIONS: Contrary to the pervasive paradigm, SCs progress through cell cycle more quickly than more differentiated dividing CPs. Thus, somatic human adult keratinocyte SCs may divide infrequently, but divide rapidly when they divide. Additionally, it was found that SC-like proliferation persisted in vitro.

The road from transcription to protein synthesis is paved with many obstacles, allowing for several modes of post-transcriptional regulation of gene expression. A fundamental player in mRNA biology is DDX3X, an RNA binding protein that canonically regulates mRNA translation. By monitoring dynamics of mRNA abundance and translation following DDX3X depletion, we observe stabilization of translationally suppressed mRNAs. We use interpretable statistical learning models to uncover GC content in the coding sequence as the major feature underlying RNA stabilization. This result corroborates GC content-related mRNA regulation detectable in other studies, including hundreds of ENCODE datasets and recent work focusing on mRNA dynamics in the cell cycle. We provide further evidence for mRNA stabilization by detailed analysis of RNA-seq profiles in hundreds of samples, including a Ddx3x conditional knockout mouse model exhibiting cell cycle and neurogenesis defects. Our study identifies a ubiquitous feature underlying mRNA regulation and highlights the importance of quantifying multiple steps of the gene expression cascade, where RNA abundance and protein production are often uncoupled.

Histone deacetylases (HDACs) play a crucial role in transcriptional regulation and are implicated in various diseases, including cancer. They are involved in histone tail deacetylation and canonically linked to transcriptional repression. Previous studies suggested that HDAC recruitment to cell-cycle gene promoters via the retinoblastoma (RB) protein or the DREAM complex through SIN3B is essential for G1/S and G2/M gene repression during cell-cycle arrest and exit. Here we investigate the interplay among DREAM, RB, SIN3 proteins, and HDACs in the context of cell-cycle gene repression. Knockout of SIN3B does not globally derepress cell-cycle genes in non-proliferating HCT116 and C2C12 cells. Loss of SIN3A/B moderately upregulates several cell-cycle genes in HCT116 cells but does so independently of DREAM/RB. HDAC inhibition does not induce general upregulation of RB/DREAM target genes in arrested transformed or non-transformed cells. Our findings suggest that E2F:RB and DREAM complexes can repress cell-cycle genes without relying on HDAC activity.

Chinese hamster ovary (CHO) cells represent the most preferential host cell system for therapeutic monoclonal antibody (mAb) production. Enhancing mAb production in CHO cells can be achieved by adding chemical compounds that regulate the cell cycle and cell survival pathways. This study investigated the impact of ectoine supplementation on mAb production in CHO cells. The results showed that adding ectoine at a concentration of 100 mM on the 3rd day of cultivation improved mAb production by improving cell viability and extending the culture duration. RNA sequencing analysis revealed differentially expressed genes associated with cell cycle regulation, cell proliferation, and cellular homeostasis, in particular promotion of cell cycle arrest, which was then confirmed by flow cytometry analysis. Ectoine-treated CHO cells exhibited an increase in the number of cells in the G0/G1 phase. In addition, the cell diameter was also increased. These findings support the hypothesis that ectoine enhances mAb production in CHO cells through mechanisms involving cell cycle arrest and cellular homeostasis. Overall, this study highlights the potential of ectoine as a promising supplementation strategy to enhance mAb production not only in CHO cells but also in other cell lines. [Display omitted] • Ectoine improved mAb production in CHO cells. • Ectoine improved cell viability and extended the culture duration of CHO cells. • Ectoine increased the number of CHO cells in the G0/G1 phase. • Enhanced mAb production involved cell cycle arrest and cellular homeostasis. • Ectoine is a promising supplement to enhance mAb production in cell lines. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death worldwide, and classifying the developmental stages of HCC can help with early prognosis and treatment. This study aimed to investigate diagnostic and prognostic molecular signatures underlying the progression of HCC, including tumor initiation and growth, and to classify its developmental stages based on gene expression levels. We integrated data from two cancer systems, including 78 patients with Edmondson-Steiner (ES) grade and 417 patients with TNM stage cancer. Functional profiling was performed using identified signatures. Using a multinomial logistic regression model (MLR), we classified controls, early-stage HCC, and advanced-stage HCC. The model was validated in three independent cohorts comprising 45 patients (neoplastic stage), 394 patients (ES grade), and 466 patients (TNM stage). Multivariate Cox regression was employed for HCC prognosis prediction. We identified 35 genes with gradual upregulation or downregulation in both ES grade and TNM stage patients during HCC progression. These genes are involved in cell division, chromosome segregation, and mitotic cytokinesis, promoting tumor cell proliferation through the mitotic cell cycle. The MLR model accurately differentiated controls, early-stage HCC, and advanced-stage HCC across multiple cancer systems, which was further validated in various independent cohorts. Survival analysis revealed a subset of five genes from TNM stage (HR: 3.27, p < 0.0001) and three genes from ES grade (HR: 7.56, p < 0.0001) that showed significant association with HCC prognosis. The identified molecular signature not only initiates tumorigenesis but also promotes HCC development. It has the potential to improve clinical diagnosis, prognosis, and therapeutic interventions for HCC. This study enhances our understanding of HCC progression and provides valuable insights for precision medicine approaches. • 35 genes gradually regulate in HCC progression in both cancer stage and grade. • These molecular signatures enhance cell proliferation via impact on the mitotic cycle. • Using MLR model, 10 genes accurately classify HCC stages across cancer systems. • Statistically significant subsets of genes emerge as prognostic markers for HCC. [ABSTRACT FROM AUTHOR]

Background and Purpose: Prostate cancer remains a major public health burden worldwide. Polo like kinase 4 (PLK4) has emerged as a promising therapeutic target in prostate cancer due to its key roles in cell cycle regulation and tumour progression. This study aims to develop and characterize the novel curcumin analogue NL13 as a potential therapeutic agent and PLK4 inhibitor against prostate cancer. Experimental Approach: NL13 was synthesized and its effects were evaluated in prostate cancer cells and mouse xenograft models. Kinome screening and molecular modelling identified PLK4 as the primary target. Antiproliferative and proapoptotic mechanisms were explored via cell cycle, apoptosis, gene and protein analyses. Key Results: Compared with curcumin, NL13 exhibited much greater potency in inhibiting PC3 (IC50, 3.51 μM vs. 35.45 μM) and DU145 (IC50, 2.53 μM vs. 29.35 μM) prostate cancer cells viability and PLK4 kinase activity (2.32 μM vs. 246.88 μM). NL13 induced G2/M cell cycle arrest through CCNB1/CDK1 down‐regulation and triggered apoptosis via caspase‐9/caspase‐3 cleavage. These effects were mediated by PLK4 inhibition, which led to the inactivation of the AKT signalling pathway. In mice, NL13 significantly inhibited tumour growth and modulated molecular markers consistent with in vitro findings, including decreased p‐AKT and increased cleaved caspase‐9/3. Conclusion and Implications: NL13, a novel PLK4‐targeted curcumin analogue, exerts promising anticancer properties against prostate cancer by disrupting the PLK4‐AKT‐CCNB1/CDK1 and apoptosis pathways. NL13 represents a promising new agent for prostate cancer therapy. [ABSTRACT FROM AUTHOR]

Background and Purpose: Gastrointestinal tumours overexpress voltage‐gated calcium (CaV3) channels (CaV3.1, 3.2 and 3.3). CaV3 channels regulate cell growth and apoptosis colorectal cancer. Gossypol, a polyphenolic aldehyde found in the cotton plant, has anti‐tumour properties and inhibits CaV3 currents. A systematic study was performed on gossypol blocking mechanism on CaV3 channels and its potential anticancer effects in colon cancer cells, which express CaV3 isoforms. Experimental Approach: Transcripts for CaV3 proteins were analysed in gastrointestinal cancers using public repositories and in human colorectal cancer cell lines HCT116, SW480 and SW620. The gossypol blocking mechanism on CaV3 channels was investigated by combining heterologous expression systems and patch‐clamp experiments. The anti‐tumoural properties of gossypol were estimated by cell proliferation, viability and cell cycle assays. Ca2+ dynamics were evaluated with cytosolic and endoplasmic reticulum (ER) Ca2+ indicators. Key Results: High levels of CaV3 transcripts correlate with poor prognosis in gastrointestinal cancers. Gossypol blockade of CaV3 isoforms is concentration‐ and use‐dependent interacting with the closed, activated and inactivated conformations of CaV3 channels. Gossypol and CaV3 channels down‐regulation inhibit colorectal cancer cell proliferation by arresting cell cycles at the G0/G1 and G2/M phases, respectively. CaV3 channels underlie the vectorial Ca2+ uptake by endoplasmic reticulum in colorectal cancer cells. Conclusion and Implications: Gossypol differentially blocked CaV3 channel and its anticancer activity was correlated with high levels of CaV3.1 and CaV3.2 in colorectal cancer cells. The CaV3 regulates cell proliferation and Ca2+ dynamics in colorectal cancer cells. Understanding this blocking mechanism maybe improve cancer therapies. [ABSTRACT FROM AUTHOR]

PTBP1KD-BMSCs can reduce the cerebral infarction volume, neurological function score, and improve neuronal damage in rats with ischemia–reperfusion, which is attributed to the down-regulation of PTBP1 , which inhibits the proliferation of BMSCs, slows down cell aging, and enhances cell viability. PTBP1KD-BMSCs may play a protective role in regulating ferroptosis by inhibiting the JNK/P38 pathway to increase the antioxidant activity and inhibit lipid peroxidation in neurons with ischemia–reperfusion injury. [Display omitted] • PTBP1KD-BMSCs treat ischemia–reperfusion injury in neurons. • PTBP1 regulates the BMSC cell cycle and increases cell viability. • PTBP1KD-BMSCs conditioned medium protects PC12 cells from OGD/R. • It inhibits ferroptosis and regulates the P38/JNK pathway in PC12 cells. Over the years, the neuroprotective potential of bone marrow mesenchymal stem cells (BMSCs) in acute ischemic stroke has attracted significant attention. However, BMSCs face challenges like short metabolic cycles and low survival rates post-transplant. Polypyrimidine tract-binding protein 1 (PTBP1) is an immunomodulatory RNA-binding protein that regulates the cell cycle and increases cell viability. This study investigated the protective effects and underlying mechanism of PTBP1 knockdown in BMSCs (PTBP1KD-BMSCs) following ischemia–reperfusion injury (IRI) in neurons. BMSCs were isolated from Sprague-Dawley rat femurs and characterized through flow cytometry and differentiation induction. PTBP1 knockdown inhibited BMSCs proliferation. Co-culture with PTBP1KD-BMSCs decreased reactive oxygen species (ROS) and malondialdehyde (MDA) levels, while increasing glutathione (GSH) production in oxygen and glucose deprivation/reperfusion-induced PC12 cells. Transcriptome sequencing analysis of PC12 cells suggested that the protective effect of PTBP1KD-BMSCs against injury may involve ferroptosis. Furthermore, western blotting showed upregulation of glutathione synthetase (GSS), glutathione peroxidase 4 (GPX4), and solute carrier family 7 member 11 (SLC7A11) in PTBP1KD-BMSCs, known negative regulators of ferroptosis. Moreover, PTBP1KD-BMSCs inhibited p38MAPK and JNK activation. In addition, PTBP1KD-BMSCs transplantation into middle cerebral artery occlusion/reperfusion (MCAO/R) rats reduced cerebral infarction volume and improved neurological function. Immunofluorescence analysis confirmed the upregulation of GSS expression in neurons of the ischemic cortex, while immunohistochemistry indicated a downregulation of p-P38. These result suggest that PTBP1KD-BMSCs can alleviate neuronal IRI by reducing oxidative stress, inhibiting ferroptosis, and modulating the MAPK pathway, providing a theoretical basis for potential treatment strategies for cerebral IRI. [ABSTRACT FROM AUTHOR]

Medicinal signaling cells (MSC) hold promise for regenerative medicine due to their ability to repair damaged tissues. However, their effectiveness can be affected by how long they are cultured in the lab. This study investigated how passage number influences key properties for regenerative medicine of pig bone marrow MSC. The medicinal signiling cells derived from pig bone marrow (BM-MSC) were cultured in D-MEM High Glucose supplemented with 15% foetal bovine serum until the 25th passage and assessed their growth, viability, ability to differentiate into different cell types (plasticity), and cell cycle activity. Our findings showed that while the cells remained viable until the 25th passage, their ability to grow and differentiate declined after the 5th passage. Additionally, cells in later passages spent more time in a resting phase, suggesting reduced activity. In conclusion, the number of passages is a critical factor for maintaining ideal MSC characteristics. From the 9th passage BM-MSC exhibit decline in proliferation, differentiation potential, and cell cycle activity. Given this, it is possible to suggest that the use of 5th passage cells is the most suitable for therapeutic applications. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is naturally produced by plant cells during normal development and serves as a messenger that regulates cell metabolism. Despite its importance, the relationship between hydrogen peroxide and the target of rapamycin (TOR) pathway, as well as its impact on cell division, has been poorly analyzed. In this study, we explore the interaction of H2O2 with TOR, a serine/threonine protein kinase that plays a central role in controlling cell growth, size, and metabolism in Arabidopsis thaliana. By applying two concentrations of H2O2 exogenously (0.5 and 1 mM), we could correlate developmental traits, such as primary root growth, lateral root formation, and fresh weight, with the expression of the cell cycle gene CYCB1;1, as well as TOR expression. When assessing the expression of the ribosome biogenesis-related gene RPS27B, an increase of 94.34% was noted following exposure to 1 mM H2O2 treatment. This increase was suppressed by the TOR inhibitor torin 2. The elimination of H2O2 accumulation with ascorbic acid (AA) resulted in decreased cell division as well as TOR expression. The potential molecular mechanisms associated with the effects of H2O2 on the cell cycle and TOR expression in roots are discussed in the context of the results. [ABSTRACT FROM AUTHOR]

The intricate immunomodulatory mechanism underlying the onset and progression of chronic rhinosinusitis with nasal polyps (CRSwNP) in chronic sinusitis with nasal polyps remains poorly understood, particularly regarding the regulatory role of dendritic cells (DCs). MicroRNA has been identified as a modulator of DC function. Primary cells have a short time in vitro and their biological characteristics have not changed greatly which can better reflect the growth state of cells in the body, so as to obtain data closer to the physiological function in the body. Our research group has been engaged in the culture of human nasal epithelial progenitor cells (hNEPCs) for a long time, and in previous investigations, we observed downregulation of microRNA‐124 (miR‐124) in patients with chronic sinusitis and nasal polyps. Thus, our current study aims to elucidate the regulatory mechanism of DCs in chronic sinusitis with polyps by examining the impact of miR‐124 on DCs in this context. To accomplish this, we took the nasal mucosa of CRSwNP patients and normal nasal mucosa of non‐rhinitis patients for primary culture. We isolated exosomes from these cells for co‐culture experiments with DCs. Flow cytometry analysis was employed to assess the maturation phenotypes (MHC II, CD80 and CD86), cell cycle and apoptosis levels of DCs. Furthermore, enzyme‐linked immunosorbent assay was utilized to measure the levels of pro‐inflammatory cytokines (IL‐10, IL‐12 and IL‐23). The TLR4/NF‐κB signalling pathway in co‐cultured DCs was evaluated using the western blot assay. Through querying the Targetscan website, we predicted Rab27a as a target gene of miR‐124, which was subsequently validated through double luciferase assay, flow cytometry and other experimental approaches. Our findings demonstrate that MiR‐124 modulates the secretion of CRSwNP epithelial exosomes, thereby influencing DC function via its interaction with the target gene Rab27a. These results offer novel insights into potential therapeutic targets for the treatment of CRSwNP. [ABSTRACT FROM AUTHOR]

Cholangiocarcinoma (CCA) is a hepatobiliary carcinoma with uncontrolled cell proliferation, poor prognosis, and high mortality. The ovarian tumor structural domain (OTU) containing protein 6B (OTUD6B) belongs to the OTU deubiquitin family and is vital in tumor development. However, its expression and biological function in CCA remain unknown. The expression of OTUD6B in CCA was analyzed using TIMER2.0, UALCAN, and GEO databases. MTT, clonal formation assay, immunofluorescence staining, immunohistochemistry staining, and flow cytometry examined the regulation of OTUD6B on cell proliferation, cycle, and apoptosis. The effects of OTUD6B on tumor volume and weight were assessed using the xenograft tumor model. The activities of PTK2 and STAT3 were detected by western blot and CO‐IP. The biological database identified that OTUD6B was upregulated in CCA. In CCA cells, OTUD6B knockdown reduced CCA cell proliferation and promoted apoptosis. Cell cycle analysis indicated that the cycle stopped at the G0/G1 phase after OTU6B downregulation. Furthermore, OTUD6B knockdown resulted in a decrease in tumor volume and weight in xenograft tumor models. Mechanistically, OTUD6B is involved in the deubiquitination of PTK2. PTK2 further affected the phosphorylation of STAT3 thereby regulating the CCA process. Our study demonstrates that OTUD6B knockdown participates in the ubiquitination of PTK2 and phosphorylation of STAT3 to alleviate the process of CCA. These results suggest that OTUD6B may be a potential new strategy for CCA treatment. [ABSTRACT FROM AUTHOR]

Parecoxib, a well‐recognized nonsteroidal anti‐inflammatory drug, has been reported to possess anticancer properties in various tumor types. In this work, we aimed to investigate the potential anticancer effects of parecoxib on hepatocellular carcinoma (HCC) cells. To assess the impact of parecoxib on HCC cell proliferation, we employed Cell Counting Kit‐8, colony formation, and 5‐ethynyl‐2′‐deoxyuridine assays. Hoechst/propidium iodide (PI) double staining and flow cytometry were performed to evaluate apoptosis and cell cycle analysis. Wound healing and transwell assays were utilized to assess cell migration and invasion. Tube formation assay was employed to analyze angiogenesis. Protein levels were determined using western blotting, and mRNA expression levels were assessed using quantitative real‐time polymerase chain reaction (PCR). A xenograft mouse model was used to confirm the antitumor effects of parecoxib on HCC tumors in vivo. Our data demonstrated that parecoxib effectively inhibited the proliferation of HCC cells in a dose‐ and time‐dependent manner. In addition, parecoxib induced cell cycle arrest in the G2 phase and promoted apoptosis. Moreover, parecoxib hindered tumor migration and invasion by impeding the epithelial–mesenchymal transition process. Further investigation showed that parecoxib could significantly suppress angiogenesis through the inhibition of extracellular signal‐regulated kinase (ERK)–vascular endothelial growth factor (VEGF) axis. Notably, treatment with the ERK activator phorbol myristate acetate upregulated the expression of matrix metalloproteinase (MMP)‐2, MMP‐9, and VEGF and reversed the function of parecoxib in HCC cells. Besides, parecoxib displayed its antitumor efficacy in vivo. Collectively, our results suggest that parecoxib ameliorates HCC progression by regulating proliferation, cell cycle, apoptosis, migration, invasion, and angiogenesis through the ERK–VEGF/MMPs signaling pathway. [ABSTRACT FROM AUTHOR]

Background: Triple-negative breast cancer (TNBC) represents the most aggressive subtype of breast cancer and is frequently resistant to therapy, ultimately resulting in treatment failure. Clinical trials have demonstrated the potential of sensitizing radiation therapy (RT)-resistant TNBC through the combination of chemotherapy and RT. This study sought to explore the potential of CD151 as a therapy response marker in the co-treatment strategy involving ionizing radiation (IR) and the repurposed antiviral drug 2-Thio-6-azauridine (TAU) for sensitizing RT-resistant TNBC (TNBC/RR). Methods: The investigation encompassed a variety of assessments, including viability using MTT and LDH assays, cell proliferation through BrdU incorporation and clonogenic assays, cell cycle analysis via flow cytometry, cell migration using wound scratch and Boyden chamber invasion assays, DNA damage assessment through γH2AX analysis, apoptosis evaluation through acridine-orange and ethidium bromide double staining assays, as well as caspase 3 activity measurement using a colorimetric assay. CD151 expression was examined through ELISA, flow cytometry and RT-qPCR. Results: The results showed a significant reduction in TNBC/RR cell viability following co-treatment. Moreover, the co-treatment reduced cell migration, induced apoptosis, downregulated CD151 expression, and increased caspase 3 activity in TNBC/RR cells. Additionally, CD151 was predicted to serve as a therapy response marker for co-treatment with TAU and IR. Conclusion: These findings suggest the potential of combination treatment with IR and TAU as a promising strategy to overcome RT resistance in TNBC. Furthermore, CD151 emerges as a valuable therapy response marker for chemoradiotherapy. [ABSTRACT FROM AUTHOR]

Background: The role of selinexor, a targeted inhibitor of exportin 1 (XPO1), in the treatment of cholangiocarcinoma is not yet fully understood. This study conducted comprehensive in vitro and in vivo investigations to elucidate the effects of selinexor on cholangiocarcinoma, with a focus on its mechanistic relationship with the cellular localization of Paternally Expressed Gene 3 (PEG3). Methods: A patient-derived xenograft (PDX) model was established using samples from a cholangiocarcinoma patient in immunodeficient mice to assess the in vivo effects of selinexor. Additionally, cholangiocarcinoma cell lines HuCC-T1 and BRE were cultured to evaluate selinexor's impact on cell proliferation, invasion, migration, cell cycle, and apoptosis. HuCC-T1 cells were also implanted in immunodeficient mice for further investigation. Immunofluorescence and Western blotting were employed to observe the expression and localization of the PEG3 protein. Results: The results demonstrated that selinexor significantly inhibited tumor growth in the cholangiocarcinoma PDX model and promoted the accumulation of PEG3 protein within the nuclei of tumor cells. In vitro experiments showed that selinexor effectively suppressed cholangiocarcinoma cell proliferation, invasion, and migration, while also impeding the cell cycle and inducing apoptosis. Notably, selinexor markedly facilitated the nuclear accumulation of PEG3 protein in cholangiocarcinoma cells. However, when PEG3 expression was knocked down, the effects of selinexor on cholangiocarcinoma were significantly reversed. Conclusion: These findings suggest that selinexor inhibits the progression of cholangiocarcinoma by targeting XPO1 and promoting the nuclear accumulation of PEG3 protein, thereby hindering the cell cycle and inducing apoptosis. [ABSTRACT FROM AUTHOR]

Background: Myasthenia gravis (MG) is a both neuromuscular junction and antibody-mediated autoimmune disease, and its pathogenesis involves the regulation of circular RNAs (circRNAs). However, the role of circ_0076490 in MG and the underlying mechanism remain unknown. Methods: RNA levels of circ_0076490, microRNA-144-3p (miR-144-3p), and mitogen-activated protein kinase 1 (MAPK1) were detected by quantitative real-time polymerase chain reaction. Cell viability and proliferation were investigated by cell counting kit-8 and 5-Ethynyl-29-deoxyuridine assays, respectively. Cell cycle and apoptosis were assessed by flow cytometry analysis. The putative binding relationship of miR-144-3p and circ_0076490 or MAPK1 was predicted by circular RNA interactome and TargetScan online databases, respectively, and identified through dual-luciferase reporter assay and RNA pull-down assay. Results: We observed dramatic increases of circ_0076490 and MAPK1 expression and a decrease of miR-144-3p expression in the peripheral blood of MG patients in comparison with healthy controls. Reduced expression of circ_0076490 induced an inhibitory effect on the proliferation of Jurkat cells and a promoting effect on cell apoptosis. Additionally, miR-144-3p was identified as a target miRNA of circ_0076490, and its depletion attenuated circ_0076490 knockdown-mediated effects on the proliferation and apoptosis of Jurkat cells. MAPK1 was a target gene of miR-144-3p and its overexpression rescued decreased cell proliferation and increased cell apoptosis induced by miR-144-3p introduction. Furthermore, circ_0076490 regulated MAPK1 expression by interacting with miR-144-3p. Conclusion: Circ_0076490 knockdown inhibited proliferation and induced apoptosis of Jurkat cells through the regulation of the miR-144-3p/MAPK1 axis, providing potential targets for developing improved therapy of MG. [ABSTRACT FROM AUTHOR]

Kirsten rat sarcoma viral oncogene homologue (KRAS) is one of the most frequently mutated proto-oncogenes in approximately 90% of pancreatic ductal carcinoma (PDAC) and 45% of colorectal cancer (CC) cases. Studies in the past have identified microRNA-217 (miR-217) as a potential tumour-suppressing miRNA that is downregulated in various cancers. Using in silico prediction algorithms, several studies have identified miR-217 as a potential regulator of KRAS, and we investigated its role in PDAC and CC progression. The study was carried out in KRAS-driven cancer (KDC) cell lines PANC-1 (pancreatic cancer) and SW-480 (CC), which have mutant KRAS gene expression. The KDC cells are transfected with specific oligonucleotides for miR-217, anti-miR-217, and a negative control in serum-free media using lipofectamine. After fixing the IC 50 , using specific primers, gene expression studies were carried out by qPCR for KRAS downstream targets and genes associated with apoptosis and cell cycle. Anti-migration and anti-apoptotic effects were studied using the transwell migration assay and annexin-V/PI staining methods, and mitochondrial morphology was observed using a transmission electron microscope. The present study demonstrates that overexpression of miR-217 in KDC cells mitigates proliferation and migration and promotes cell cycle arrest and apoptosis of KDC cells via the MAPK/ERK signalling pathway. Besides, decreased miR-217 expression rescues KDC cells from the effects mediated by KRAS downstream signalling. The outcome of the study indicates miR-217 suppresses tumour growth and promotes apoptosis in KDC and that these effects are associated with down regulation of MAPK/ERK signalling. [ABSTRACT FROM AUTHOR]

The cell cycle is the sequence of events orchestrated by a complex network of cell cycle proteins. Unlike normal cells, mature neurons subsist in a quiescent state of the cell cycle, and aberrant cell cycle activation triggers neuronal death accompanied by neurodegeneration. The periodicity of cell cycle events is choreographed by various mechanisms, including DNA damage repair, oxidative stress, neurotrophin activity, and ubiquitin-mediated degradation. Given the relevance of cell cycle processes in cancer and neurodegeneration, this review delineates the overlapping cell cycle events, signaling pathways, and mechanisms associated with cell cycle aberrations in cancer and the major neurodegenerative disorders. We suggest that dysregulation of some common fundamental signaling processes triggers anomalous cell cycle activation in cancer cells and neurons. We discussed the possible use of cell cycle inhibitors for neurodegenerative disorders and described the associated challenges. We propose that a greater understanding of the common mechanisms driving cell cycle aberrations in cancer and neurodegenerative disorders will open a new avenue for the development of repurposed drugs. Cell cycle activation and cell cycle re-entry are the two critical cellular phenomena associated with cancer and neurodegeneration, respectively. Various regulatory proteins, such as cyclin-dependent kinases (CDKs), cyclins, and checkpoint kinases, control the cell cycle dynamics at different phases. Further, the integrity of cell cycle is controlled by different mechanisms like DNA damage response, oxidative stress, neurotrophin activity, and the ubiquitin–proteasome system (UPS), the alterations which play an essential role in the pathogenesis of both cancer and neurodegenerative disorders. Pharmacological targeting of important cell cycle regulatory molecules like the application of CDK inhibitors, PARP inhibitors, checkpoint kinase inhibitors, and microtubule inhibitors holds great promise for treating various human cancers and can be repurposed for different neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

The spermatogenic capacity of adult individuals depends on, among other factors, the number of Sertoli cells (SCs) that result from the proliferative waves during development. FSH upregulates SC proliferation at least partly, through the activation of the PI3K/Akt/mTORC1 pathway, among other mechanisms. It is widely known that mTORC1 is a sensor of amino acids. Among amino acids, glutamine acquires relevance since it might contribute to cell cycle progression through the modulation of mTORC1 activity. It has not been studied yet whether glutamine intervenes in FSH-mediated regulation of SC proliferation and cell cycle progression, or if FSH has any effect on glutamine metabolism. Eight-day-old rat SCs were incubated in culture media without glutamine or with glutamine in the absence or presence of a glutamine transporter inhibitor or a glutaminase activity inhibitor under basal conditions or stimulated with FSH. The results obtained show that FSH does not promote SC proliferation and mTORC1 activation in the absence of glutamine. Also, FSH modulates glutamine metabolism increasing glutaminase isoform 2 and reducing glutamine synthetase expression. FSH did not promote SC proliferation and mTORC1 activation when glutaminase activity was inhibited. The results suggest that glutamine or its metabolites might cooperate with FSH in the upregulation of SC proliferation through mTORC1. In addition, as FSH modulates glutamine metabolism through the induction of glutaminase isoform 2, the hormonal control of glutamine metabolism might be part of the intricate signaling network triggered by FSH, which is crucial to establish the population of mature SCs that supports the reproductive function. [ABSTRACT FROM AUTHOR]

Aim: The therapeutic potential of senolytic drugs in osteoarthritis (OA) is poorly known. Quercetin, a senolytic agent exhibits promising potential to treat OA, having limited bioavailability. We investigated the effects of Quercetin-loaded nanoparticles (Q-NP) with enhanced bioavailability in human chondrocytes mimicking OA phenotype. Materials & methods: The C-20/A4 chondrocytes were exposed to ferric ammonium citrate to induce OA phenotype, followed by treatment with free Quercetin/Q-NP for 24 and 48-h. Q-NP were synthesized by nanoprecipitation method. Following treatment chondrocytes were assessed for drug cellular bioavailability, viability, cell cycle, apoptosis, oxidative stress and expression of key senescence markers. Results: Q-NP exhibited 120.1 ± 1.2 nm particle size, 81 ± 2.4% encapsulation efficiency, increased cellular bioavailability and selective apoptosis of senescent chondrocytes compared with free Quercetin. Q-NP treatment also induced oxidative stress and reduced the expressions of senescence markers, including TRB3, p16, p62 and p21 suggesting their ability to eliminate senescent cells. Last, Q-NP arrested the cell cycle in the sub-G0 phase, potentially creating a beneficial environment for tissue repair. Conclusion: Q-NP propose a promising delivery system for treating OA by eliminating senescent chondrocytes through apoptosis. Furthermore, their enhanced cellular bioavailability and capacity to modify cell cycle and senescent pathways warrant further investigations. Graphical Abstract Article highlights Quercetin-loaded nanoparticles (Q-NP) were successfully produced with a small, uniform size (120 nm) and a negative surface charge (-26.8 mV), indicating stability and potential for drug delivery. Over 81% of Quercetin, a poorly soluble drug, was encapsulated within the nanoparticles, suggesting efficient loading. Scanning electron microscopy revealed Q-NP with a smooth, spherical shape, ideal for drug entrapment. Compared with free Quercetin, Q-NP significantly increased Quercetin's solubility within the first 3 h, demonstrating enhanced drug delivery potential. Surprisingly Q-NP showed reduced cell viability compared with free Quercetin. Initially, Q-NP increased reactive oxygen species (ROS) production, a sign of oxidative stress, but levels decreased after 48 h compared with free Quercetin. Q-NP effectively reduced markers of cellular senescence compared with free Quercetin, suggesting a long-term protective effect. Q-NP caused cell cycle arrest, potentially preventing further damage from iron overload. Q-NP increased the number of pro-apoptotic cells compared with controls, suggesting they trigger programmed cell death in damaged cells. While Q-NP demonstrated positive effects in reducing senescence and promoting cell cycle arrest, the initial increase in ROS and the unexpected impact on cell viability require further exploration. [ABSTRACT FROM AUTHOR]

Non‐small cell lung cancer (NSCLC) is the primary inducer of cancer‐related death worldwide. Asiaticoside (ATS) is a triterpenoid saponin that has been indicated to possess an antitumor activity in several malignancies. Nonetheless, its detailed functions in NSCLC remain unclarified. In this study, NSCLC cells were exposed to various doses of ATS. Functional experiments were employed to estimate the ATS effect on NSCLC cell behaviors. Western blotting was implemented for protein expression evaluation. A xenograft mouse model was established to assess the ATS effect on NSCLC in vivo. The results showed that ATS restrained NSCLC cell proliferation, cell cycle progression, migration, and invasiveness. ATS reversed TGF‐β‐induced promotion in epithelial‐mesenchymal transition (EMT). Mechanistically, ATS inhibited Wnt/β‐catenin signaling in NSCLC. Upregulating β‐catenin restored ATS‐mediated suppression of NSCLC cell aggressiveness. Moreover, ATS administration repressed tumorigenesis in tumor‐bearing mice. In conclusion, ATS represses growth and metastasis in NSCLC by blocking EMT via the inhibition of Wnt/β‐catenin signaling. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) are implicated in the progression of breast cancer (BC). However, the explorations on circRNA IQ motif containing H (circIQCH) in BC progression remain limited. Functional experiments were conducted using in vitro and murine xenograft model assays, respectively. Dual‐luciferase reporter assay and RIP assay detected the associations among circIQCH, miR‐139‐5p, and nuclear factor IB (NFIB). CircIQCH was upregulated in BC, and the silencing of circIQCH repressed BC cell growth, metastasis, and autophagy, arrested cell cycle, promoted cell apoptosis in vitro, and blocked tumor growth in vivo. CircIQCH positively modulated NFIB expression by sponging miR‐139‐5p. Moreover, the deletion of miR‐139‐5p abated the action of circIQCH deficiency on BC cell malignant behaviors. Overexpression of miR‐139‐5p repressed the malignant characteristics of BC cells, while these impacts were abolished by elevating NFIB. Collectively, CircIQCH functioned as an oncogene in BC through upregulating NFIB expression by sponging miR‐139‐5p. [ABSTRACT FROM AUTHOR]

Context CHEK2 is a cell cycle checkpoint regulator gene with a long-established role as a clinically relevant, moderate risk breast cancer predisposition gene, with greater risk ascribed to truncating variants than missense variants. Objective To assess the rate and pathogenicity of CHEK2 variants amongst individuals with pituitary adenomas (PAs). Methods We assessed 165 individuals with PAs for CHEK2 variants. The study population comprised a primary cohort of 29 individuals who underwent germline and tumor whole-exome sequencing, and a second, independent cohort of 136 individuals who had a targeted next-generation sequencing panel performed on both germline and tumor DNA (n = 52) or germline DNA alone (n = 84). Results We identified rare, coding, nonsynonymous germline CHEK2 variants amongst 3 of 29 (10.3%) patients in our primary cohort, and in 5 of 165 (3.0%) patients overall, with affected patients having a range of PA types (prolactinoma, thyrotropinoma, somatotropinoma, and nonfunctioning PA). No somatic variants were identified. Two variants were definitive null variants (c.1100delC, c.444 + 1G > A), classified as pathogenic. Two variants were missense variants (p.Asn186His, p.Thr476Met), classified as likely pathogenic. Even when considering the null variants only, the rate of CHEK2 variants was higher in our cohort compared to national control data (1.8% vs 0.5%; P =.049). Conclusion This is the first study to suggest a role for the breast cancer predisposition gene, CHEK2 , in pituitary tumorigenesis, with pathogenic/likely pathogenic variants found in 3% of patients with PAs. As PAs are relatively common and typically lack classic autosomal dominant family histories, risk alleles—such as these variants found in CHEK2 —might be a significant contributor to PA risk in the general population. [ABSTRACT FROM AUTHOR]

Telomerase reverse transcriptase (TERT) gene aberration is detectable in >80% of cases with hepatocellular carcinoma (HCC). TERT reactivation is essential for cellular immortalization because it stabilizes telomere length, although the role of TERT in hepatocarcinogenesis remains unelucidated. To elucidate the significance of aberrant TERT expression in hepatocytes in inflammation‐associated hepatocarcinogenesis, we generated Alb‐Cre;TertTg mice, which overexpress TERT in the liver and examined their phenotype during chronic inflammation. Based on transcriptome data from the liver tissue of Alb‐Cre;TertTg mice, we examined the role of TERT in hepatocarcinogenesis in vitro. We also evaluated the relationship between TERT and cell‐cycle‐related molecules, including p21, in HCC samples. The liver tumor development rate was increased by TERT overexpression during chronic inflammation, especially in the absence of p53 function. Gene set enrichment analysis of liver tissues revealed that gene sets related to TNF‐NFκB signaling, cell cycle, and apoptosis were upregulated in Alb‐Cre;TertTg liver. A luciferase reporter assay and immunoprecipitation revealed that TERT interacted with NFκB p65 and enhanced NFκB promoter activity. On the other hand, TERT formed protein complexes with p21, cyclin A2, and cyclin E and promoted ubiquitin‐mediated degradation of p21, specifically in the G1 phase. In the clinical HCC samples, TERT was highly expressed but p21 was conversely downregulated, and TERT expression was associated with the upregulation of molecules related to the cell cycle. Taken together, the aberrant upregulation of TERT increased NFκB promoter activity and promoted cell cycle progression via p21 ubiquitination, leading to hepatocarcinogenesis. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland. [ABSTRACT FROM AUTHOR]

Plastic waste comprises polymers of different chemicals that disintegrate into nanoplastic particles (NPLs) of 1–100‐nm size, thereby littering the environment and posing a threat to wildlife and human health. Research on NPL contamination has up to now focused on the ecotoxicology effects of the pollution rather than the health risks. This review aimed to speculate about the possible properties of carcinogenic and neurotoxic NPL as pollutants. Given their low‐dimensional size and high surface size ratio, NPLs can easily penetrate biological membranes to cause functional and structural damage in cells. Once inside the cell, NPLs can interrupt the autophagy flux of cellular debris, alter proteostasis, provoke mitochondrial dysfunctions, and induce endoplasmic reticulum stress. Harmful metabolic and biological processes induced by NPLs include oxidative stress (OS), ROS generation, and pro‐inflammatory reactions. Depending on the cell cycle status, NPLs may direct DNA damage, tumorigenesis, and lately carcinogenesis in tissues with high self‐renewal capabilities like epithelia. In cells able to live the longest like neurons, NPLs could trigger neurodegeneration by promoting toxic proteinaceous aggregates, OS, and chronic inflammation. NPL genotoxicity and neurotoxicity are discussed based on the gathered evidence, when available, within the context of the intracellular uptake of these newcomer nanoparticles. In summary, this review explains how the risk evaluation of NPL pollution for human health may benefit from accurately monitoring NPL toxicokinetics and toxicodynamics at the intracellular resolution level. Plastic waste disintegrates into nanoplastic particles (NPLs), whose health hazards are unknown. This review deals with their carcinogenic and neurotoxic potential. Given their low‐dimensional size and high surface size ratio, NPLs can easily penetrate cells to provoke structural and functional damages through OS and pro‐inflammatory reactions, which may cause carcinogenesis and/or neurodegeneration. The NPL role in these diseases is discussed within the context of the intracellular uptake of these newcomer nanoparticles. [ABSTRACT FROM AUTHOR]

The genome duplication program is affected by multiple factors in vivo , including developmental cues, genotoxic stress, and aging. Here, we monitored DNA replication initiation dynamics in regenerating livers of young and old mice after partial hepatectomy to investigate the impact of aging. In young mice, the origin firing sites were well defined; the majority were located 10–50 kb upstream or downstream of expressed genes, and their position on the genome was conserved in human cells. Old mice displayed the same replication initiation sites, but origin firing was inefficient and accompanied by a replication stress response. Inhibitors of the ATR checkpoint kinase fully restored origin firing efficiency in the old mice but at the expense of an inflammatory response and without significantly enhancing the fraction of hepatocytes entering the cell cycle. These findings unveil aging-dependent replication stress and a crucial role of ATR in mitigating the stress-associated inflammation, a hallmark of aging. [Display omitted] • Partial hepatectomy enables in vivo mapping of DNA replication origins in mouse livers • Most origins are located 10–50 kb upstream or downstream of expressed genes • An aging-dependent reduction in origin firing is mediated by the ATR checkpoint • ATR inhibitors restore origin firing in old mice but lead to liver inflammation In vivo DNA replication dynamics in regenerating mouse livers unveil aging-dependent decline in replication efficiency and a crucial role of the ATR checkpoint kinase in mitigating inflammation associated with the decline. [ABSTRACT FROM AUTHOR]

The morphology of ray florets in chrysanthemums is tightly associated with cell division and expansion, both of which require proper progression of the cell cycle. Here, we identified a Chrysanthemum lavandulifolium homolog, CYCLIN A2;1 (CYCA2;1), the expression of which in ray florets is negatively correlated with petal width. We found that CYC2a, a TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) transcription factor in the CYCLOIDEA2 (CYC2) family, interacts with and stabilizes CYC2b, and the latter can bind to the promoter of CYCA2;1 to activate its transcription. Overexpression of CYCA2;1 in C. lavandulifolium reduced the size of capitula and ray florets. Cytological analysis revealed that CYCA2;1 overexpression inhibited both cell division and expansion via repression of the mitotic cell cycle in ray florets, the latitudinal development of which was more relatively negatively influenced, thereby leading to increased ratios of petal length to width at later developmental stages. Yeast two-hybrid library screening revealed multiple proteins that interacted with CYCA2;1 including ACTIN-RELATED PROTEIN7 (ARP7), and silencing ARP7 inhibited the development of ray florets. Co-immunoprecipitation assays confirmed that CYCA2;1 could induce the degradation of ARP7 to inhibit the development of ray florets. Taken together, our results indicate the presence of a regulatory network in ray floret development in chrysanthemum consisting of CYC2b–CYCA2;1–ARP7 that acts via governing mitosis. The identification of this network has the potential to facilitate breeding efforts targeted at producing novel ornamental traits in the flowers. [ABSTRACT FROM AUTHOR]

Background: Transforming growth factor beta (TGFβ) is important for the morphogenesis and secretory function of the mammary gland. It is one of the main activators of the epithelial–mesenchymal transition (EMT), a process important for tissue remodeling and regeneration. It also provides cells with the plasticity to form metastases during tumor progression. Noncancerous and cancer cells respond differently to TGFβ. However, knowledge of the cellular signaling cascades triggered by TGFβ in various cell types is still limited. Methods: MCF10A (noncancerous, originating from fibrotic breast tissue) and MCF7 (cancer, estrogen receptor-positive) breast epithelial cells were treated with TGFB1 directly or through conditioned media from stimulated cells. Transcriptional changes (via RNA-seq) were assessed in untreated cells and after 1–6 days of treatment. Differentially expressed genes were detected with DESeq2 and the hallmark collection was selected for gene set enrichment analysis. Results: TGFB1 induces EMT in both the MCF10A and MCF7 cell lines but via slightly different mechanisms (signaling through SMAD3 is more active in MCF7 cells). Many EMT-related genes are expressed in MCF10A cells at baseline. Both cell lines respond to TGFB1 by decreasing the expression of genes involved in cell proliferation: through the repression of MYC (and the protein targets) in MCF10A cells and the activation of p63-dependent signaling in MCF7 cells (CDKN1A and CDKN2B, which are responsible for the inhibition of cyclin-dependent kinases, are upregulated). In addition, estrogen receptor signaling is inhibited and caspase-dependent cell death is induced only in MCF7 cells. Direct incubation with TGFB1 and treatment of cells with conditioned media similarly affected transcriptional profiles. However, TGFB1-induced protein secretion is more pronounced in MCF10A cells; therefore, the signaling is propagated through conditioned media (bystander effect) more effectively in MCF10A cells than in MCF7 cells. Conclusions: Estrogen receptor-positive breast cancer patients may benefit from high levels of TGFB1 expression due to the repression of estrogen receptor signaling, inhibition of proliferation, and induction of apoptosis in cancer cells. However, some TGFB1-stimulated cells may undergo EMT, which increases the risk of metastasis. Plain English summary: Transforming growth factor beta (TGFβ) is a multifaceted cytokine that controls numerous physiological and pathological processes during development and carcinogenesis. Its best-known function is the activation of epithelial–mesenchymal transition (EMT), a process crucial for tissue remodeling and regeneration. During EMT, epithelial cells lose their connections to adjacent cells and acquire mesenchymal characteristics, such as migratory ability. Compared with cancer cells, normal (nontumorigenic) cells usually respond differently to TGFβ stimulation. Typically, TGFβ inhibits the proliferation of epithelial cells and may promote cell death. In cancer cells, TGFβ often promotes tumor progression. TheTGFβ-mediated induction of EMT increases cell mobility, which is associated with the formation of metastases and tumor invasion. In this work, we compared the transcriptional response of noncancerous (MCF10A) and cancerous (MCF7; estrogen receptor-positive) breast epithelial cells to direct stimulation by TGFB1 and its indirect effect through conditioned media. Some of TGFB1-induced changes, including inhibition of proliferation and induction of EMT, were similar in both cell lines. However, these changes were associated with different upstream signaling pathways. Other changes were more specific, such as disruption of estrogen-related signaling or induction of cell death in MCF7 cells. Direct incubation with TGFB1 and treatment of cells with conditioned media similarly affected target cells, indicating the presence of a bystander effect. Moreover, transcript profiling by RNA-seq revealed that the TGFβ signaling pathway is already active in untreated MCF10A cells, which may be due to their origination from a fibrotic lesion. [ABSTRACT FROM AUTHOR]

Lithium titanate oxide (LTO) batteries are a promising technology, particularly suitable for high‐power applications, owing to their inherent cyclic stability, fast charging capability, and superior safety. However, substantial gas generation and accelerated aging driven by the cathode remain substantial challenges. This study explores the mitigation of these aging mechanisms through the application of external mechanical compression. Continuous pressure of 0.3 MPa applied to pristine cells during cycling reduces capacity loss by 42% compared to unpressurized cells cycled under identical operating conditions. Applying short‐term pressure to aged cells leads to immediate capacity recovery, reclaiming up to 57% of the lost capacity. Subsequent cycling of these aged cells under continuous pressure demonstrates improved capacity retention. In contrast, intermittently applied transient pressure causes notable capacity fluctuations. This study reveals insights into aging and healing mechanisms influenced by external pressure, benefiting both first‐ and second‐life battery applications. Understanding these mechanisms is vital for enhancing performance and lifetime in battery packs, while the findings also highlight promising opportunities for capacity recovery in reused batteries. [ABSTRACT FROM AUTHOR]

Clonorchis sinensis infection is an important risk factor for cholangiocarcinoma (CCA). It has been reported that extracellular vesicles (EVs) are involved in the parasite-host interaction, and EVs of C. sinensis (CsEVs) can contribute to biliary injuries and inflammation. However, uncertainty surrounds the function of CsEVs in the progression of CCA. In this study, differential ultracentrifugation was used to separate CsEVs from the culture supernatant of C. sinensis adult worms, and they were then identified by transmission electron microscopy, nanoparticle tracking analysis and proteome assays. CCK8, EdU-488 and colony formation assays were used to explore the effect of CsEVs on the proliferation of CCA cells in vitro. Wound healing assays, transwell assays and in vivo lung metastasis model were conducted to evaluate the migration and invasion abilities. Moreover, the involvement of EMT process, as well as NF-κB and ERK signaling pathway was assessed. Results showed that CsEVs were successfully isolated and could be taken up by CCA cells, which promoted proliferation by accelerating cell cycle progression. In addition, CsEVs could facilitate cell metastasis by triggering the epithelial-mesenchymal transition (EMT). Mechanistically, activation of NF-κB signaling pathway was involved in the CsEVs-mediated EMT, which could be reversed partly by BAY 11–7082 (an inhibitor of NF-κB). In conclusion, these findings suggested that CsEVs could induce the aberrant proliferation and metastasis of CCA cells by stimulating the NF-κB/EMT axis, providing a novel theoretical explanation for liver fluke-associated CCA. Author summary: C. sinensis infection is closely related to the occurrence of CCA, and the International Agency for Research on Cancer (IARC) has classified C. sinensis as a class I carcinogen. The exact mechanism of C. sinensis causing CCA remains to be elucidated, which may be the result of the synergistic effect of multiple factors such as mechanical damage caused by the migration of C. sinensis adult worms, secondary bacterial infection and inflammatory response, toxicity of the excretory-secretory products, abnormal host immune response and gene mutations. Recently, extracellular vesicles have emerged as a potential mechanism participating in parasite-host interaction, and CsEVs may play an important role in the pathogenesis and carcinogenesis of C. sinensis. In this study, it was discovered that EVs isolated from the culture supernatant of C. sinensis adult worms could facilitate the abnormal proliferation of CCA cells by regulating cell cycle progression, and promote the migration, invasion and EMT process through activating the NF-κB signaling pathway. Furthermore, the protein expression profile of CsEVs is revealed by this study, which provides a new perspective for the study of liver fluke-associated CCA and may therefore contribute to the development of novel therapeutic approaches to treat CCA caused by C. sinensis infection. [ABSTRACT FROM AUTHOR]

Purpose: Wilms' tumor (WT), also known as nephroblastoma, is the predominant form of primary malignant renal cancer. The unfavorable prognoses linked to anaplastic nephroblastoma and recurrent nephroblastoma emphasize the crucial requirement for the exploration of innovative treatment modalities for WT. Methods: Our study conducted one-way Cox regression and Kaplan-Meier analyses using TARGET-WT nephroblastoma data to identify differentially expressed genes in nephroblastoma and evaluate their prognostic relevance. Utilizing the Connectivity Map database, ZSTK474 emerged as a viable therapeutic option for WT. The effect of ZSTK474 on WT and related underlying mechanisms were further investigated through in vitro and in vivo investigations. Results: The in vivo experiment results indicated that ZSTK474 effectively inhibited subcutaneous tumor growth in WT mice. CCK-8 assays revealed two nephroblastoma cell lines exhibited half-inhibitory concentrations of 2μM and 2.51μM for ZSTK474, respectively. ZSTK474 was shown to inhibit the migration and invasion capabilities of WT cells in both Transwell and wound healing assays. Flow cytometry apoptosis and TUNEL assays demonstrated that ZSTK474 induced apoptosis in WT cells. Cell cycle analysis revealed that ZSTK474 led to the induction of G0/G1 phase arrest. Sequencing of ZSTK474-treated WiT49 cells suggested that the impact of ZSTK474 on WT might be mediated by the PI3K/Akt pathway, specifically by inhibiting PIK3R3. Knock-down of PIK3R3 confirmed that ZSTK474 downregulated PIK3R3, reducing Akt phosphorylation, cyclin D and CDK4 levels and elevating P21 expression in nephroblastoma cells. However, current research has limitations, including a lack of understanding of the long-term effects and potential resistance mechanisms of new therapies. Conclusion: This research provides insight into the potential of ZSTK474 and other PI3K inhibitors for treating nephroblastoma. [ABSTRACT FROM AUTHOR]

Background: Pancreatic cancer is a malignant tumor of the digestive tract with a high mortality rate. Erianin has antitumor activity, but the regulatory targets and mechanism of action in pancreatic cancer are unclear. The objective of this study was to evaluate the anti-pancreatic cancer activity of Erianin and explore its underlying mechanisms. Methods: A network pharmacology approach was used to investigate the mechanism of action of Erianin in pancreatic cancer cells. Cell proliferation was analyzed using CCK8, colony-formation, and EdU proliferation assays. Cell migration was evaluated through wound healing and transwell assays, as well as determination of the protein expression levels of EMT markers and β-catenin. Apoptosis and the cell cycle were measured using flow cytometry and JC-1 staining, respectively. The protein expression levels of p-Rb, CyclinB1, P21, Cleaved-PARP, and Cleaved-Caspase3 were assessed using western blotting. RNA sequencing (RNA-seq) and bioinformatics analyses were performed to elucidate the mechanism underlying the action of Erianin in pancreatic cancer. Western blotting was used to examine the expression levels of key proteins in the AKT, JNK, and p38 MAPK signaling pathways. Molecular docking and CETSA were used to test hypotheses. The tumor-suppressive ability of Erianin in vivo was assessed using a tumor-bearing assay in nude mice. Results: Network pharmacology revealed that Erianin inhibited pancreatic cancer through multiple pathways. Erianin significantly inhibited pancreatic cancer cell proliferation and migration while promoting intracellular ROS and inducing apoptosis. Mechanistically, Erianin inhibited pancreatic cancer cell proliferation by regulating the AKT/FOXO1 and ASK1/JNK/p38 MAPK signaling pathways. In vivo experiments showed that Erianin inhibited subcutaneous tumor growth and promoted tumor tissue apoptosis in nude mice. Conclusions: The component-target-pathway network revealed that Erianin exerted anti-cancer effects through multiple components, targets, and pathways. Erianin inhibited the proliferation and migration of pancreatic cancer cells and induced apoptosis through the AKT/FOXO1 and ASK1/JNK/p38 MAPK signaling pathways. These results indicate that Erianin is a promising agent for pancreatic cancer treatment. [ABSTRACT FROM AUTHOR]

Background: Glioma is a highly heterogeneous and poorly immunogenic malignant tumor, with limited efficacy of immunotherapy. The characteristics of the immunosuppressive tumor microenvironment (TME) are one of the important factors hindering the effectiveness of immunotherapy. Therefore, this study aims to reveal the immune microenvironment (IME) characteristics of glioma and predict different immune subtypes using machine learning methods, providing guidance for immune therapy in glioma. Methods: We first performed unsupervised cluster analysis on the genes and arrays of 693 gliomas in CGGA database and 702 gliomas in TCGA database. Then establish and verify the classification model through Machine Learning (ML). Then, use DAVID to perform functional enrichment analysis for different immune subtypes. Next step, analyze the immune cell distribution, stemness maintenance, mesenchymal phenotype, neuronal phenotype, tumorigenic cytokines, molecular and clinical characteristics of different immune subtypes of gliomas. Results: Firstly, we divide the IME of gliomas in the CGGA database into four different subtypes, namely IM1, IM2, IM3, and IM4; similarly, the IME of gliomas in the TCGA database can also be divided into four different subtypes (IMA, IMB, IMC, and IMD). Next, based on ML, we developed a highly reliable model for predicting different immune subtypes of glioma. Then, we found that Monocytic lineage, Myeloid dendritic cells, NK cells and CD8 T cells had the highest enrichment in the IM1/IMD subtypes. Cytotoxic lymphocytes were highest expressed in the IM4/IMA subtypes. Next step, Enrichment analysis revealed that the IM1-IMD subtypes were mainly closely related to the production and secretion of IL-8 and TNF signaling pathway. The IM2-IMB subtypes were strongly associated with leukocyte activation and NK cell mediated cytotoxicity. The IM3-IMC subtypes were closely related to mitotic nuclear division and mitotic cell cycle process. The IM4-IMA subtypes were strongly associated with Central Nervous System (CNS) development and striated muscle tissue development. Afterwards, Single sample gene set enrichment analysis (ssGSEA) showed that stemness maintenance phenotypes were mainly enriched in the IM4/IMA subtypes; Neuronal phenotypes were closely associated with the IM2/IMB subtypes; and mesenchymal phenotypes and tumorigenic cytokines were highly correlated with the IM2 /IMB subtypes. Finally, we found that compared with patients in the IM2/IMB and IM4/IMA subtypes, the IM1/IMD and IM3/IMC subtypes have the highest proportion of GBM patients, the shortest average overall survival of patients and the lowest proportion of patients with IDH mutation and 1p36/19q13 co-deletion. Conclusions: We developed a highly reliable model for predicting different immune subtypes of glioma by ML. Then, we comprehensively analyzed the immune infiltration, molecular and clinical features of different immune subtypes of gliomas and defined gliomas into four subtypes: immunogenic subtype, adaptive immune resistance subtype, mesenchymal subtype, and immune tolerance subtype, which represent different TMEs and different stages of tumor development. [ABSTRACT FROM AUTHOR]

Malignant tumors are among the most important causes of death worldwide. The pathogenesis of a malignant tumor is complex and has not been fully elucidated. Studies have shown that such pathogenesis is related to abnormal cell cycle progression. The expression levels of cyclins, cyclin-dependent kinases (CDKs), and CDK inhibitors as well as functions of the cell cycle checkpoints determine whether the cell cycle progression is smooth. Cell-cycle-targeting drugs have the advantages of high specificity, low toxicity, low side effects, and low drug resistance. Identifying drugs that target the cell cycle and applying them in clinical treatments are expected to promote chemotherapeutic developments against malignant tumors. This article aims to review drugs targeted against the cell cycle and their action mechanisms. [ABSTRACT FROM AUTHOR]

Background: Animal and human health are seriously threatened by bacterial infections, which can lead to bacteremia and extremely high rates of morbidity and mortality. Recently, there have been reports indicating the involvement of exosomal circular RNAs (circRNAs) in a range of human disorders and tumor types. However, the role of exosomal circRNAs in bacterial infection remains elusive. Methods: We extracted and identified exosomes from the culture medium of PIEC cells infected with or without Glaesserella parasuis. RNA sequencing analysis was performed on the exosomes to screen and identify circRNAs (circHIF1α) associated with Glaesserella parasuis infection. PIEC cells were infected with Staphylococcus aureus or Streptococcus suis 2 to further determine whether exosome-derived circHIF1α was the crucial circHIF1α associated with bacterial infections. The transmission process of exosomes and their circHIF1α between cells was clarified via exosome tracing and co-culture assay. Moreover, the mechanism of circHIF1α being packaged into exosomes was explored, and the effects of exosomes and their circHIF1α on cell proliferation, DNA damage and cell cycle were analyzed. In addition, the binding mode and site of interacting proteins with circHIF1α were further determined. In vivo and in vitro, the role of exosomes and their circHIF1α in host resistance to bacterial infection was confirmed. Results: We first discovered a new circHIF1α that was very stable and detectable, encapsulated into exosomes by hnRNPA2B1, and whose expression in exosomes of bacterially infected PIEC cells significantly decreased. Additionally, exosomal circHIF1α reduced bacterial infection both in vitro and in vivo and suppressed the growth of reception cells. Mechanistically, the circHIF1α interacted with the KH domain of IGF2BP3 in an m6A-modified manner, which mediated DNA damage to arrest the cells at the G1/S phase through the interaction between the regulator of Chromosome Condensation 2 (RCC2) and γ-H2AX protein. Exosomal circHIF1α is a unique therapeutic target for bacterial infection since this work highlights its critical function in fighting bacterial infection. [ABSTRACT FROM AUTHOR]

The most common type of non-small cell lung cancer is lung adenocarcinoma (LUAD), which is characterized by high morbidity and poor survival. Up-regulation of SASS6 expression can lead to the progression of various malignant tumors. However, there are no relevant studies on the role of SASS6 in LUAD. SASS6 was highly expressed in most tumors, reflecting a good diagnostic value, and its overexpression in LUAD indicated discouraging overall prognosis. Functional enrichment analysis suggested that SASS6 was associated with cell cycle in LUAD. In addition, patients with high SASS6 expression had worse immune infiltration, but higher TMB and immune checkpoint, and higher sensitivity to multiple targeted drugs such as osimertinib. Cell experiments confirmed that knockdown of SASS6 could inhibit the viability of tumor cells.SASS6 has important value in the diagnosis of cancer. In particular, SASS6 is a crucial factor in the progression of LUAD, and has important clinical value, especially in the diagnosis, prognosis and treatment [ABSTRACT FROM AUTHOR]

Psoriasis is a chronic skin disease characterized by abnormal proliferation and inflammation of epidermal keratinocytes. Fibroblast growth factor 12 (FGF12) is implicated in the regulation of diverse cellular signals; however, its precise mechanism in psoriasis requires further investigation. In this study, high expression of FGF12 is observed in the epidermis of skin lesion in psoriasis patients and imiquimod (IMQ)‐induced psoriasis like‐dermatitis. Moreover, specific loss of FGF12 in keratinocytes in IMQ‐induced psoriasis model alleviates psoriasis‐like symptoms and reduces proliferation. In vitro RNA sequencing demonstrates that knockdown of FGF12 effectively arrests the cell cycle, inhibits cell proliferation, and predominantly regulates the p53 signaling pathway. Mechanistically, FGF12 is selectively bound to the RING domain of MDM2, thus partially inhibiting the binding of β‐Trcp to MDM2. This interaction inhibits β‐Trcp‐induced‐K48 ubiquitination degradation of MDM2, thereby suppressing the activity of the p53 signaling pathway, which results in excessive cell proliferation. Last, the alleviatory effect of FGF12 deficiency on psoriasis progression is reversed by p53 knockdown. In summary, these findings provide valuable insights into the mechanisms by which FGF12 suppresses p53 signaling in keratinocytes, exacerbating the development of psoriasis. This positive regulatory loop highlights the potential of FGF12 as a therapeutic target to manage psoriasis. [ABSTRACT FROM AUTHOR]

DYRK1A, a ubiquitously expressed kinase, is linked to the dominant intellectual developmental disorder, microcephaly, and Down syndrome in humans. It regulates numerous cellular processes such as cell cycle, vesicle trafficking, and microtubule assembly. DYRK1A is a critical regulator of organ growth; however, how it regulates organ growth is not fully understood. Here, we show that the knockdown of DYRK1A in mammalian cells results in reduced cell size, which depends on mTORC1. Using proteomic approaches, we found that DYRK1A interacts with the tuberous sclerosis complex (TSC) proteins, namely TSC1 and TSC2, which negatively regulate mTORC1 activation. Furthermore, we show that DYRK1A phosphorylates TSC2 at T1462, a modification known to inhibit TSC activity and promote mTORC1 activity. We also found that the reduced cell growth upon knockdown of DYRK1A can be rescued by overexpression of RHEB, an activator of mTORC1. Our findings suggest that DYRK1A inhibits TSC complex activity through inhibitory phosphorylation on TSC2, thereby promoting mTORC1 activity. Furthermore, using the Drosophila neuromuscular junction as a model, we show that the mnb, the fly homologs of DYRK1A, is rescued by RHEB overexpression, suggesting a conserved role of DYRK1A in TORC1 regulation. [ABSTRACT FROM AUTHOR]

Background: Hepatocellular carcinoma (HCC) is a malignant tumor characterized by a high mortality rate. The occurrence and progression of HCC are linked to oxidative stress. Glyoxalase-1 (GLO1) plays an important role in regulating oxidative stress, yet the underlying mechanism remains unclear. GLO1 may serve as a prognostic biomarker and therapeutic target for HCC. Methods: Based on TCGA database hepatocellular carcinoma samples, we conducted a bioinformatics analysis to explore the correlation between GLO1 expression and HCC cell proliferation and viability. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that differentially expressed genes (DEGs) were mainly enriched in the cell cycle pathway. We analyzed the relationships between GLO1 and 24 genes enriched in the cell cycle pathway using a protein-protein interaction (PPI) network. Finally, experimental validation was performed to assess GLO1's impact on the distribution of cells at different cell cycle stages and on the proliferation and migration of HCC cells. Results: Our study demonstrated that GLO1 was overexpressed in HCC tissues and was associated with a poor prognosis. Data analysis indicated that overexpression of GLO1 activated the cell cycle pathway and positively correlated with expression of the majority of key cell cycle genes. Experimental validation showed that GLO1 expression affects the number of HCC cells in G2 and S phases and regulates HCC cell proliferation and migration. Conclusions: GLO1 represents a promising therapeutic target for HCC, providing valuable insights into its role in the viability and proliferation of HCC cells. [ABSTRACT FROM AUTHOR]

Natural compounds and their derivatives have been identified as valuable sources of therapeutic ingredients for cancer treatment. The naturally occurring phytochemical palmatine (isoquinoline alkaloid) is extracted from plant parts (rhizomes, roots, stems, stem barks, and others) and has protective effects including antioxidant, anti‐inflammatory, and anticancer. This study aims to summarize the anticancer potential of palmatine and its derivatives in the treatment of numerous types of cancer with molecular mechanisms. We also include the pharmacokinetic features, botanical origin, and toxicological characteristics of palmatine and its derivatives. For this, data have been collected from plausible different electronic databases, including PubMed, Google Scholar, PubChem, Science Direct, Web of Science, Scopus, Springer Link, and Wiley Online. The findings demonstrate that palmatine and its derivatives have a protective anticancer effect against a variety of cancers, including breast, colorectal, gastric, ovarian, prostate, pancreatic, skin, hepatocellular cancer, and mammary gland tumors. They provoke their anticancer properties against various cancer cell lines via modifying molecular mechanisms like induction of oxidative stress, cytotoxicity, apoptosis, inhibition of cell invasion and migration, arresting the cell cycle at the S phase, antiproliferative, and antiangiogenic effects. It is suggested that palmatine and its derivatives may be a good option in the development of novel drugs for cancer therapy in the future. [ABSTRACT FROM AUTHOR]

The failure of lithium‐sulfur (Li‐S) batteries operating under lean‐ether‐electrolyte conditions can be ascribed to the deterioration of electrolytes, the passivation of cathodes, and the degeneration of lithium anodes. Efforts to address these challenges by exploring alternative electrolytes beyond commonly used ether‐based systems often introduce new complications. In this study, the utilization of a multifunctional additive, 2‐Bromoacetamide (BA), for ether electrolytes is proposed to achieve stable Li‐S batteries under lean‐electrolyte conditions. These investigations reveal that the amide bond in BA forms hydrogen bonds with sulfur atoms, promoting the dissolution of lithium sulfides (Li2S) in ether electrolytes and mediating the conversion of lithium polysulfides. This enhanced solubility of Li2S facilitates 3D deposition (vertical to the substrate) rather than the typical 2D deposition (parallel to the substrate) of Li2S, and thus alleviates the passivation of cathodes. Furthermore, the incorporation of BA promotes uniform and dense lithium deposition. The use of the BA‐containing electrolyte enables stable cycling of a Li‐S pouch cell for 40 cycles, even under a low electrolyte‐to‐sulfur ratio of 4 µL mg−1. This multifunctional strategy offers an effective solution to extend the lifetime of Li‐S batteries under lean‐electrolyte conditions, thereby paving the way for practical applications of Li‐S battery technology. [ABSTRACT FROM AUTHOR]

The acquisition of mitochondria was imperative for initiating eukaryogenesis and thus is a characteristic feature of eukaryotic cells. 1,2 The parasitic protist Trypanosoma brucei contains a singular mitochondrion with a unique mitochondrial genome, termed the kinetoplast DNA (kDNA). 3 Replication of the kDNA occurs during the G 1 phase of the cell cycle, prior to the start of nuclear DNA replication. 4 Although numerous proteins have been functionally characterized and identified as vital components of kDNA replication and division, the molecular mechanisms governing this highly precise process remain largely unknown. 5,6 One division-related and morphologically characteristic structure that remains most enigmatic is the "nabelschnur," an undefined, filament-resembling structure observed by electron microscopy between segregating daughter kDNA networks. 7,8,9 To date, only one protein, TbLAP1, an M17 family leucyl aminopeptidase metalloprotease, is known to localize to the nabelschnur. 9 While screening proteins from the T. brucei MitoTag project, 10 we identified a previously uncharacterized protein with an mNeonGreen signal localizing to the kDNA as well as forming a point of connection between dividing kDNAs. Here, we demonstrate that this kDNA-associated protein, named TbNAB70, indeed localizes to the nabelschnur and plays an essential role in the segregation of newly replicated kDNAs and subsequent cytokinesis in T. brucei. [Display omitted] • TbNAB70 localizes to both the kDNA and the nabelschnur in Trypanosoma brucei • TbNAB70 is identified to be vital for the segregation, but not replication, of kDNA • TbNAB70 depletion results in a near-complete arrest of cytokinesis • TbNAB70 evolutionary emergence occurred after the development of the kDNA network Cadena et al. identify TbNAB70 as localizing to the "nabelschnur," an enigmatic structure observed between dividing kDNA networks in Trypanosoma brucei. TbNAB70 is shown to be essential for the segregation of kDNA and basal bodies, while the loss of TbNAB70 results in the arrest of cytokinesis, highlighting its critical role in cellular division processes. [ABSTRACT FROM AUTHOR]

Ribosomal biosynthesis in nucleoli is an energy-demanding process driven by all RNA polymerases and hundreds of auxiliary proteins. We investigated how this process is regulated in activated T lymphocytes by T cell receptor (TCR) signals and the multiprotein complexes mTORC1 and mTORC2, both of which contain the kinase mTOR. Deficiency in mTORC1 slowed the proliferation of T cells, with further delays in each consecutive division, an effect not seen with deficiency in mTORC2. mTORC1 signaling was stimulated by components of conventional TCR signaling, and, reciprocally, TCR sensitivity was decreased by mTORC1 inhibition. The substantial increase in the amount of RNA per cell induced by TCR activation was reduced by 50% by deficiency in mTORC1, but not in mTORC2 or in S6 kinases 1 and 2, which are activated downstream of mTORC1. RNA-seq data showed that mTORC1 deficiency reduced the abundance of all RNA biotypes, although rRNA processing was largely intact in activated T cells. Imaging cytometry with FISH probes for nascent pre-rRNA revealed that deletion of mTORC1, but not that of mTORC2, reduced the number and expansion of nucleolar sites of active transcription. Protein translation was consequently decreased by 50% in the absence of mTORC1. Inhibiting RNA polymerase I blocked not only proliferation but also mTORC1 signaling. Our data show that TCR signaling, mTORC1 activity, and ribosomal biosynthesis in the nucleolus regulate each other during biomass production in clonally expanding T cells. Editor's summary: Activated T cells must ramp up ribosomal biogenesis in nucleoli to support protein synthesis required for proliferation. Rosenlehner et al. investigated the interplay among T cell receptor (TCR) signaling, ribosomal biosynthesis, and mTORC1, a multiprotein complex implicated in cell growth and proliferation. mTORC1 was required for the rapid cell cycling of proliferating activated T cells. In addition, mTORC1 heightened the antigen sensitivity of the TCR, promoted ribosomal RNA synthesis, and increased the number and size of nucleoli. These effects were not seen with the related mTORC2 complex. In turn, the activity of mTORC1 correlated with that of the TCR and with ribosomal RNA transcription mediated by RNA polymerase I. These results uncover the reciprocal regulation between signaling pathways and cellular processes that enable the proliferation of activated T cells. —Wei Wong [ABSTRACT FROM AUTHOR]

Introduction: The mutated in colorectal cancer (MCC) gene was initially identified as a candidate tumor suppressor gene in colorectal cancer, acting as a negative regulator of cell cycle progression. However, its functional roles in brain tumors, particularly glioblastoma, remain largely unexplored. This study reveals a significant association between MCC status and glioblastoma. Methods: We explored MCC expression in the glioblastoma database, patient samples, and cell lines. We investigated the proliferation and migration of the cell lines in MCC gene knockdown using small interfering RNA. Results: In vitro analyses revealed elevated protein and mRNA levels of MCC in several glioblastoma cell lines (U118MG and T98G). Silencing MCC expression via siRNA-mediated knockdown resulted in increased proliferation and migration of these cell lines. Supporting these findings, analyses of The Cancer Genome Atlas (TCGA), Chinese Glioma Genome Atlas (CGGA), and Genotype-Tissue Expression (GTEx) databases confirmed higher MCC expression in glioblastoma tumors than in normal brain tissue. Importantly, we observed that high MCC expression was associated with poor prognosis in glioblastoma patients, highlighting its potential role in disease progression. Additionally, this study identifies a nuclear localization of MCC in the glioblastoma cell line. Discussion: These findings indicate that MCC expression is significantly upregulated in glioblastoma and may play a role in its pathophysiology, warranting further investigation. [ABSTRACT FROM AUTHOR]