Mitotic Spindle Research Articles

Chromosome Gene, Hsl7 Gene in Vitro Studies

Chromosome gene can expression many functions in human body. Eukaryotic cells are presence in yeast and human, in order to more understanding human gene, we use yeast as a model to research. The ORF (open reading frame) position of the Hsl7 gene is in yeast Saccharomyces YBR133C between 501804bp~504287bp of Chromosome II, with a total length of 2483bp, and the protein size is 95 kDa. Hsl7 gene is a methyltransferase. Protein-arginine N-methyltransferase involved in protein catabolism and regulation of the G2/M transition of mitosis; localizes to the septin collar of the bud neck, and the outer plaque of the spindle pole body in the G1 phase of the cell cycle (Saccharomyces Genome Database), Hsl7 (histone synthetic lethal 7) represent protein methylation, protein methylation is a type of post-translational modification that involves the addition of methyl groups to proteins, Protein methylation, including histone methylation and non-histone protein methylation, is one of the most important forms of posttranscriptional and epigenetic modifications.

The central spindle drives anaphase chromosome segregation.

Anaphase chromosome segregation depends on forces exerted by spindle microtubules. In the current model, forces on chromosomes are mediated through the spindle poles: sliding of antiparallel microtubules in the central spindle pushes poles apart, while kinetochore microtubule (kMT) depolymerization pulls chromosomes towards the poles. Here we show that the central spindle is directly linked to the chromosomes rather than the poles in anaphase, based on three lines of evidence. Chromosomes in monopolar spindles can move away from the pole, consistent with forces exerted by antiparallel microtubule sliding. In bipolar spindles, kMT depolymerization is constrained by suppressing central spindle sliding, indicating kinetochore linkage to the central spindle. Finally, increasing the rate of kMT depolymerization slows pole separation without increasing chromosome separation velocity. We conclude that central spindle sliding drives anaphase chromosome separation, while kMT depolymerization limits spindle elongation.

MInsc coordinates Par3 and NuMA condensates for assembly of the spindle orientation machinery in asymmetric cell division

As a fundamental process governing the self-renewal and differentiation of stem cells, asymmetric cell division is controlled by several conserved regulators, including the polarity protein Par3 and the microtubule-associated protein NuMA, which orchestrate the assembly and interplay of the Par3/Par6/mInsc/LGN complex at the apical cortex and the LGN/Gαi/NuMA/Dynein complex at the mitotic spindle to ensure asymmetric segregation of cell fate determinants. However, this model, which is well-supported by genetic studies, has been challenged by evidence of competitive interaction between NuMA and mInsc for LGN. Here, the solved crystal structure of the Par3/mInsc complex reveals that mInsc competes with Par6β for Par3, raising questions about how proteins assemble overlapping targets into functional macromolecular complexes. Unanticipatedly, we discover that Par3 can recruit both Par6β and mInsc by forming a dynamic condensate through phase separation. Similarly, the phase-separated NuMA condensate enables the coexistence of competitive NuMA and mInsc with LGN in the same compartment. Bridge by mInsc, Par3/Par6β and LGN/NuMA condensates coacervate, robustly enriching all five proteins both in vitro and within cells. These findings highlight the pivotal role of protein condensates in assembling multi-component signalosomes that incorporate competitive protein-protein interaction pairs, effectively overcoming stoichiometric constraints encountered in conventional protein complexes.

Identification of KIFC1 as a putative vulnerability in lung cancers with centrosome amplification

Centrosome amplification (CA), an abnormal increase in the number of centrosomes in the cell, is a recurrent phenomenon in lung and other malignancies. Although CA promotes tumor development and progression by inducing genomic instability (GIN), it also induces mitotic stress that jeopardizes cellular integrity. CA leads to the formation of multipolar mitotic spindles that can cause lethal chromosome segregation errors. To sustain the benefits of CA by mitigating its consequences, malignant cells are dependent on adaptive mechanisms that represent therapeutic vulnerabilities. We aimed to discover genetic dependencies associated with CA in lung cancer. Combining a CRISPR/Cas9 functional genomics screen with tumor genomic analyses, we identified the motor protein KIFC1, also known as HSET, as a putative vulnerability specifically in lung adenocarcinoma (LUAD) with CA. KIFC1 expression was positively correlated with CA in LUAD and associated with worse patient outcomes, smoking history, and indicators of GIN. KIFC1 loss-of-function sensitized LUAD cells with high basal KIFC1 expression to potentiation of CA, which was associated with a diminished ability to cluster extra centrosomes into pseudo-bipolar mitotic spindles. Our work suggests that KIFC1 inhibition represents a novel approach for potentiating GIN to lethal levels in LUAD with CA by forcing cells to divide with multipolar spindles, rationalizing further studies to investigate its therapeutic potential.

Advancing Cancer Therapy: The Role of KIF20A as a Target for Inhibitor Development and Immunotherapy.

The analysis begins with a detailed examination of the gene expression and protein structure of KIF20A, highlighting its interaction with critical cellular components that influence key processes such as Golgi membrane transport and mitotic spindle assembly. The primary focus is on the development of specific KIF20A inhibitors, detailing their roles and the challenges encountered in enhancing their efficacy, such as achieving specificity, overcoming tumor resistance, and optimizing delivery systems. Additionally, it delves into the prognostic value of KIF20A across multiple cancer types, emphasizing its role as a novel tumor-associated antigen, which lays the groundwork for the development of targeted peptide vaccines. The therapeutic efficacy of these vaccines as demonstrated in recent clinical trials is discussed. Future directions are proposed, including the integration of precision medicine strategies to personalize treatments and the use of combination therapies to improve outcomes. By concentrating on the significant potential of KIF20A as both a direct target for inhibitors and an antigen in cancer vaccines, this review sets a foundation for future research aimed at harnessing KIF20A for effective cancer treatment.

Bud14 function is crucial for spindle pole body size maintenance.

Spindle pole bodies (SPB), the functional equivalent of centrosomes in yeast, duplicate through generation of a new SPB next to the old one. However, SPBs are dynamic structures that can grow and exchange, and mechanisms that regulate SPB size remain largely unknown. This study aims to elucidate the role of Bud14 in SPB size maintenance in Saccharomyces cerevisiae. We employed quantitative fluorescence microscopy to assess the relative and absolute amounts of SPB structural proteins at SPBs of wildtype cells and in cells lacking BUD14 (bud14Δ). Quantifications were performed using asynchronous cell cultures, as well as cultures synchronously progressing through the cell cycle and upon different cell cycle arrests. We also utilized mutants that allow the separation of Bud14 functions. Our results indicate that higher levels of SPB inner, outer, and central plaque proteins are present at the SPBs of bud14Δ cells compared to wildtype cells during anaphase, as well as during nocodazole-induced M-phase arrest. However, during α-factor mediated G1 arrest, inner and outer plaque proteins responded differently to the absence of BUD14. A Bud14 mutant that cannot interact with the Protein Phosphatase 1 (Glc7) phenocopied bud14Δ in terms of SPB-bound levels of the inner plaque protein Spc110, whereas disruption of Bud14-Kel1-Kel2 complex did not alter Spc110 levels at SPBs. In cells synchronously released from α-factor arrest, lack of Bud14-Glc7 caused increase of Spc110 at the SPBs at early stages of the cell cycle. We identified Bud14 as a critical protein for SPB size maintenance. The interaction of Bud14 with Glc7, but not with the Kelch proteins, is indispensable for restricting levels of Spc110 incorporated into the SPBs.

Loss of symmetric cell division of apical neural progenitors drives DENND5A-related developmental and epileptic encephalopathy

Developmental and epileptic encephalopathies (DEEs) feature altered brain development, developmental delay and seizures, with seizures exacerbating developmental delay. Here we identify a cohort with biallelic variants in DENND5A, encoding a membrane trafficking protein, and develop animal models with phenotypes like the human syndrome. We demonstrate that DENND5A interacts with Pals1/MUPP1, components of the Crumbs apical polarity complex required for symmetrical division of neural progenitor cells. Human induced pluripotent stem cells lacking DENND5A fail to undergo symmetric cell division with an inherent propensity to differentiate into neurons. These phenotypes result from misalignment of the mitotic spindle in apical neural progenitors. Cells lacking DENND5A orient away from the proliferative apical domain surrounding the ventricles, biasing daughter cells towards a more fate-committed state, ultimately shortening the period of neurogenesis. This study provides a mechanism for DENND5A-related DEE that may be generalizable to other developmental conditions and provides variant-specific clinical information for physicians and families.

Thiostrepton induces spindle abnormalities and enhances Taxol cytotoxicity in MDA-MB-231 cells

BackgroundThiostrepton (TST) is a known inhibitor of the transcription factor Forkhead box M1 (FoxM1) and inducer of heat shock response (HSR) and autophagy. TST thus may be one potential candidate of anticancer drugs for combination chemotherapy.Methods and ResultsImmunofluorescence staining of mitotic spindles and flow cytometry analysis revealed that TST induces mitotic spindle abnormalities, mitotic arrest, and apoptotic cell death in the MDA-MB-231 triple-negative breast cancer cell line. Interestingly, overexpression or depletion of FoxM1 in MDA-MB-231 cells did not affect TST induction of spindle abnormalities; however, TST-induced spindle defects were enhanced by inhibition of HSP70 or autophagy. Moreover, TST exhibited low affinity for tubulin and only slightly inhibited in vitro tubulin polymerization, but it severely impeded tubulin polymerization and destabilized microtubules in arrested mitotic MDA-MB-231 cells. Additionally, TST significantly enhanced Taxol cytotoxicity. TST also caused cytotoxicity and spindle abnormalities in a Taxol-resistant cell line, MDA-MB-231-T4R.ConclusionsThese results suggest that, in addition to inhibiting FoxM1, TST may induce proteotoxicity and autophagy to disrupt cellular tubulin polymerization, and this mechanism might account for its antimitotic effects, enhancement of Taxol anticancer effects, and ability to overcome Taxol resistance in MDA-MB-231 cells. These data further imply that TST may be useful to improve the therapeutic efficacy of Taxol.

Targeting of mutant-p53 and MYC as a novel strategy to inhibit oncogenic SPAG5 activity in triple negative breast cancer

Triple negative breast cancer (TNBC) is an aggressive disease which currently has no effective therapeutic targets and prominent biomarkers. The Sperm Associated antigen 5 (SPAG5) is a mitotic spindle associated protein with oncogenic function in several human cancers. In TNBC, increased SPAG5 expression has been associated with tumor progression, chemoresistance, relapse, and poor clinical outcome. Here we show that high SPAG5 expression in TNBC is regulated by coordinated activity of YAP, mutant p53 and MYC. Depletion of YAP or mutant p53 proteins reduced SPAG5 expression and the recruitment of MYC onto SPAG5 promoter. Targeting of MYC also reduced SPAG5 expression and concomitantly tumorigenicity of TNBC cells. These effects of MYC targeting were synergized with cytotoxic chemotherapy and markedly reduced TNBC oncogenicity in SPAG5-expression dependent manner. These results suggest that mutant p53-MYC-SPAG5 expression can be considered as bona fide predictors of patient’s outcome, and reliable biomarkers for effective anticancer therapies.

Sumo-regulatory SENP2 controls the homeostatic squamous mitosis-differentiation checkpoint

Squamous or epidermoid cancer arises in stratified epithelia but also is frequent in the non-epidermoid epithelium of the lung by unclear mechanisms. A poorly studied mitotic checkpoint drives epithelial cells bearing irreparable genetic damage into epidermoid differentiation. We performed an RNA-sequencing gene search to target unknown regulators of this response and selected the SUMO regulatory protein SENP2. Alterations of SENP2 expression have been associated with some types of cancer. We found the protein to be strongly localised to mitotic spindles of freshly isolated human epidermal cells. Primary cells rapidly differentiated after silencing SENP2 with specific shRNAs. Loss of SENP2 produced in synchronised epithelial cells delays in mitotic entry and exit and defects in chromosomal alignment. The results altogether strongly argue for an essential role of SENP2 in the mitotic spindle and hence in controlling differentiation. In addition, the expression of SENP2 displayed an inverse correlation with the immuno-checkpoint biomarker PD-L1 in a pilot collection of aggressive lung carcinomas. Consistently, metastatic head and neck cancer cells that do not respond to the mitosis-differentiation checkpoint were resistant to depletion of SENP2. Our results identify SENP2 as a novel regulator of the epithelial mitosis-differentiation checkpoint and a potential biomarker in epithelial cancer.

Exploration of biomarkers for nursing physical examination early screening of multiple tumors.

Nursing and physical examination early screening of multiple tumors is helpful to find tumors early, so as to improve the cure rate. Studying its molecular mechanisms is urgent. By logging into gene expression omnibus database, we found laryngeal cancer dataset GSE127165, bladder cancer dataset GSE65635, oral cancer dataset GSE146483, obtain differentially expressed genes, subsequently, weighted gene co-expression network analysis, protein-protein interaction networks, functional enrichment analysis, immune infiltration analysis, survival analysis, comparative toxicogenomics database analysis were conducted. Draw a heatmap of gene expression. Use targetScan to search for miRNA information about core DEG. Got 53 differentially expressed genes. In GOKEGG analysis, they were clustered in cell cycle processes, spindle poles, and protein serine/threonine/tyrosine kinase activity cell cycle, transcriptional dysregulation in cancer, RIG-I-like receptor signaling pathway, P53 signaling pathway. Protein-protein interaction analysis screened out 5 genes (NEK2, BUB1, HMMR, TTK, CCNB2). Cyclin B2 (CCNB2) and budding uninhibited by benzimidazole 1 (BUB1) were highly expressed in laryngeal cancer, bladder cancer, oral cancer. Comparative toxicogenomics database analysis found that core genes (CCNB2, BUB1) are associated with tumors, necrosis, and inflammation. Related miRNA of CCNB2 gene is hsa-miR-670-3p; related miRNAs of BUB1 gene are hsa-miR-5688, hsa-miR-495-3p. CCNB2 and BUB1 exhibit high expression in laryngeal cancer, bladder cancer, and oral cancer, suggesting their potential as molecular targets for precision therapy in these cancers.

Cell scientist to watch – Alexis Barr

ABSTRACT Alexis Barr is a Cancer Research UK (CRUK) Career Development Fellow at the Institute of Clinical Sciences (ICS), Imperial College London and Medical Research Council (MRC) Investigator at the MRC Laboratory of Medical Sciences (LMS). Alexis graduated in Natural Sciences from the University of Cambridge, UK, and then undertook a PhD at the CRUK Cambridge Institute, where she studied the role of centrosomes in mitotic spindle assembly under the supervision of Fanni Gergely. For her postdoctoral studies, Alexis moved to the Institute of Cancer Research in London, where she joined the team of Chris Bakal and was awarded a Pathway to Independence Fellowship. There, she investigated the mechanisms that control cell cycle entry using quantitative single-cell imaging. In 2018, Alexis was awarded a CRUK Career Development Fellowship to start her own research group at the ICS, to research the control of cell cycle entry and exit and how these pathways can be manipulated to treat cancer. She was awarded the 2024 Women in Cell Biology Early Career Medal by the British Society for Cell Biology (BSCB). We spoke with Alexis over Zoom to find out more about her career, her advice on collaborative research and her approaches to scientific mentorship.

Spatial control of the APC/C ensures the rapid degradation of cyclin B1

The proper control of mitosis depends on the ubiquitin-mediated degradation of the right mitotic regulator at the right time. This is effected by the Anaphase Promoting Complex/Cyclosome (APC/C) ubiquitin ligase that is regulated by the Spindle Assembly Checkpoint (SAC). The SAC prevents the APC/C from recognising Cyclin B1, the essential anaphase and cytokinesis inhibitor, until all chromosomes are attached to the spindle. Once chromosomes are attached, Cyclin B1 is rapidly degraded to enable chromosome segregation and cytokinesis. We have a good understanding of how the SAC inhibits the APC/C, but relatively little is known about how the APC/C recognises Cyclin B1 as soon as the SAC is turned off. Here, by combining live-cell imaging, in vitro reconstitution biochemistry, and structural analysis by cryo-electron microscopy, we provide evidence that the rapid recognition of Cyclin B1 in metaphase requires spatial regulation of the APC/C. Using fluorescence cross-correlation spectroscopy, we find that Cyclin B1 and the APC/C primarily interact at the mitotic apparatus. We show that this is because Cyclin B1, like the APC/C, binds to nucleosomes, and identify an ‘arginine-anchor’ in the N-terminus as necessary and sufficient for binding to the nucleosome. Mutating the arginine anchor on Cyclin B1 reduces its interaction with the APC/C and delays its degradation: cells with the mutant, non-nucleosome-binding Cyclin B1 become aneuploid, demonstrating the physiological relevance of our findings. Together, our data demonstrate that mitotic chromosomes promote the efficient interaction between Cyclin B1 and the APC/C to ensure the timely degradation of Cyclin B1 and genomic stability.

Comparative Transcriptome Analysis Reveals Differential Cutaneous Gene Expression in the Color Variation of Two Ornamental Discus, Red Melon and Red Cover.

Red Melon (RM) and Red Cover (RC) discus (Symphysodon spp.) are ornamental fish varieties that were selectively bred from the wild parental lineages of the brown discus S. aquafaciatus over many generations, resulting in distinct cutaneous patterns from juveniles to adults. To better understand the underlying mechanisms, skin samples were collected from juveniles aged 60 days and adults aged 1 year from RM and RC for investigations. Microscopic observation detected xanthophores and erythrophores in all samples, except RC juveniles with no erythrophores. Melanophores were presented only in RC. The comparative analysis revealed that genes involved in pteridine synthesis (gch1 and zgc:153031), one-carbon metabolism (aldh1l2 and zgc153031), and lipid metabolism (apoda and klf1) were differentially expressed in RM juveniles, which may be associated with the development of erythrophores and xanthophores. The temporal inhibition of melanophore differentiation and development was observed in RM juveniles, coupled with elevated expression of notum2 and sost, two antagonist genes in Wnt-signaling, suggesting their roles in melanophore development. Distinct pigment pattern between RM and RC since the juvenile stage may be driven by the differential expression of multiple axial developmental genes, including GATA, ankyrin, and mitotic spindle orientation proteins. This is the first report to describe the differential growth of cutaneous pigments and the molecular processes involved in red discus. The results provided valuable insights into pigment pattern differences in an interesting ornamental fish model.

B-type plexins regulate mitosis via RanGTPase.

Aberrant mitosis can result in aneuploidy and cancer. The small GTPase, Ran, is a key regulator of mitosis. B-type Plexins regulate Ran activity by acting as RanGTPase activating proteins (GAPs) and have been implicated in cancer progression. However, whether B-type plexins have a role in mitosis has not so far been investigated. We show here that PlexinB1 functions in the control of mitosis. Depletion of PlexinB1 affects mitotic spindle assembly, significantly delaying anaphase. This leads to mitotic catastrophe in some cells, and prolonged application of the spindle assembly checkpoint. PlexinB1 depletion also promoted acentrosomal microtubule nucleation and defects in spindle pole refocussing and increased the number of cells with multipolar or aberrant mitotic spindles. An increase in lagging chromosomes or chromosomal bridges at anaphase was also found upon PlexinB1 depletion. PlexinB1 localises to the mitotic spindle in dividing cells. The mitotic defects observed upon PlexinB1 depletion were rescued by an RCC1 inhibitor, indicating that PlexinB1 signals, via Ran, to affect mitosis. These errors in mitosis generated multinucleate cells, and nuclei of altered morphology and abnormal karyotype. Furthermore, Semaphorin4D-treatment increased the percentage of cells with micronuclei, precursors of chromothripsis. Implications: Defects in B-type plexins may contribute to the well-established role of plexins in cancer progression by inducing chromosomal instability.

Ase1 selectively increases the lifetime of antiparallel microtubule overlaps

Microtubules (MTs) are dynamically unstable polar biopolymers switching between periods of polymerization and depolymerization, with the switch from the polymerization to the depolymerization phase termed catastrophe and the reverse transition termed rescue.1 In presence of MT-crosslinking proteins, MTs form parallel or anti-parallel overlaps and self-assemble reversibly into complex networks, such as the mitotic spindle. Differential regulation of MT dynamics in parallel and anti-parallel overlaps is critical for the self-assembly of these networks.2,3 Diffusible MT crosslinkers of the Ase1/MAP65/PRC1 family associate with different affinities to parallel and antiparallel MT overlaps, providing a basis for this differential regulation.4,5,6,7,8,9,10,11 Ase1/MAP65/PRC1 family proteins directly affect MT dynamics12 and recruit other proteins that locally alter MT dynamics, such as CLASP or kinesin-4.7,13,14,15,16 However, how Ase1 differentially regulates MT stability in parallel and antiparallel bundles is unknown. Here, we show that Ase1 selectively promotes antiparallel MT overlap longevity by slowing down the depolymerization velocity and by increasing the rescue frequency, specifically in antiparallelly crosslinked MTs. At the retracting ends of depolymerizing MTs, concomitant with slower depolymerization, we observe retention and accumulation of Ase1 between crosslinked MTs and on isolated MTs. We hypothesize that the ability of Ase1 to reduce the dissociation of tubulin subunits is sufficient to promote its enrichment at MT ends. A mathematical model built on this idea shows good agreement with the experiments. We propose that differential regulation of MT dynamics by Ase1 contributes to mitoticspindle assembly by specifically stabilizing antiparallel overlaps, compared to parallel overlaps or isolatedMTs.

Discovery of a 6-Aminobenzo[b]thiophene 1,1-Dioxide Derivative (K2071) with a Signal Transducer and Activator of Transcription 3 Inhibitory, Antimitotic, and Senotherapeutic Activities.

6-Nitrobenzo[b]thiophene 1,1-dioxide (Stattic) is a potent signal transducer and activator of the transcription 3 (STAT3) inhibitor developed originally for anticancer therapy. However, Stattic harbors several STAT3 inhibition-independent biological effects. To improve the properties of Stattic, we prepared a series of analogues derived from 6-aminobenzo[b]thiophene 1,1-dioxide, a compound directly obtained from the reduction of Stattic, that includes a methoxybenzylamino derivative (K2071) with optimized physicochemical characteristics, including the ability to cross the blood-brain barrier. Besides inhibiting the interleukin-6-stimulated activity of STAT3 mediated by tyrosine 705 phosphorylation, K2071 also showed cytotoxicity against a set of human glioblastoma-derived cell lines. In contrast to the core compound, a part of K2071 cytotoxicity reflected a STAT3 inhibition-independent block of mitotic progression in the prophase, affecting mitotic spindle formation, indicating that K2071 also acts as a mitotic poison. Compared to Stattic, K2071 was significantly less thiol-reactive. In addition, K2071 affected cell migration, suppressed cell proliferation in tumor spheroids, exerted cytotoxicity for glioblastoma temozolomide-induced senescent cells, and inhibited the secretion of the proinflammatory cytokine monocyte chemoattractant protein 1 (MCP-1) in senescent cells. Importantly, K2071 was well tolerated in mice, lacking manifestations of acute toxicity. The structure-activity relationship analysis of the K2071 molecule revealed the necessity of the para-substituted methoxyphenyl motif for antimitotic but not overall cytotoxic activity of its derivatives. Altogether, these results indicate that compound K2071 is a novel Stattic-derived STAT3 inhibitor and a mitotic poison with anticancer and senotherapeutic properties that is effective on glioblastoma cells and may be further developed as an agent for glioblastoma therapy.

Pan-cancer analysis and single-cell analysis reveals FAM110B as a potential target for survival and immunotherapy.

Background: FAM110B belongs to the family that has a 110 sequence similarity (FAM110) and is located in the centrosome and mitotic spindle. FAM110B has been linked to tumor cell growth in earlier research. Uncertainty exists regarding FAM110B's function within the tumor microenvironment is unclear as well as pan-cancer. Methods: In order to assess the variation in FAM110B expression within normal and pan-cancer tissues, we combined the TCGA and GTEx databases. The cBioPortal database and the GSCALite platform were used to examine the variation in genome and methylation alteration of FAM110B. Cox regression, Kaplan-Meier, and SangerBox were employed to examine the clinical features and prognosis of FAM110B and pan-cancer. The purpose of the correlational research was to investigate the associations within immunerelated genes, tumor mutation burden, microsatellite instability, immune-related genes, and immunological checkpoints and FAM110B expression. ESTIMATE, EPIC, QUANTISEQ, and MCPCOUNTER methods were used to calculate the interaction among FAM110B expression as well as the tumor immune microenvironment. The immunoinfiltration and function of FAM110B were analyzed by single-cell databases (TISCH and CancerSEA). Finally, we evaluated the sensitivity of FAM110B to small-molecule medications through GDSC and CTRP databases. Results: The transcription and protein expression of FAM110B varies significantly throughout cancer types, and this has predictive value for the prognosis of some tumors; including brain lower grade glioma (LGG), stomach adenocarcinoma (STAD), pancreatic adenocarcinoma (PAAD), etc. In the tumor microenvironment, the expression level of FAM110B was associated with immune cell infiltration, immune checkpoint immune regulatory genes, tumor mutational burden, and microsatellite fragility to a certain extent. Conclusion: This work investigates the possibility of utility of FAM110B as a marker to forecast pan-cancer immunotherapy response, providing a theoretical basis for cancer therapy.

RAD51 High-Expressed Hepatocellular Carcinomas Are Associated With High Cell Proliferation

IntroductionRAD51 is a pivotal DNA repair gene managing double-stranded DNA break recognition and repair. RAD51 high expression was associated with adverse outcomes in other cancer types. This study aims to investigate the tumor microenvironment and immune landscape in the RAD51 high-expressed Hepatocellular Carcinoma (HCCs). MethodsA total of 467 patients from two large independent cohorts with clinical and transcriptomic data were obtained. The cohort was dichotomized based on the median RAD51 gene expression. xCell and Gene Set Enrichment Analysis (GSEA) were used. ResultsRAD51 high-expressed HCCs were associated with worse recurrence-free, progression-free, disease-specific, and overall survival (all P < 0.05). While RAD51 high-expressed HCCs were associated with intratumoral heterogeneity, homologous recombination deficiency, and fraction altered scores, mutation or neoantigens were not increased in this group. xCell analysis demonstrated inconsistent immune cell infiltration between two cohorts. Cytolytic activity as well as GSEA with immune-related gene sets also demonstrated inconsistent results between two cohorts as well. On the other hand, RAD51 expression was significantly increased in higher-grade tumors, larger tumors, and higher clinical stages. RAD51 high-expressed HCCs were found to have elevated proliferation score. Furthermore, GSEA exhibited significant enrichment of all the cell proliferation–related gene sets in the Hallmark collection, including E2F targets, G2M checkpoint, Mitotic spindle, MYC targets, and MTORC1 signaling consistently in both cohorts (all false discovery rate < 0.25). ConclusionsRAD51 high-expressed HCCs were associated with worse survival and with increased cell proliferation and were not necessarily associated with immune infiltration or inflammation.

Visualizing metabolic regulation using metabolic biosensors during sea urchin embryogenesis

Growing evidence suggests that metabolic regulation directly influences cellular function and development and thus may be more dynamic than previously expected. In vivo and in real-time analysis of metabolite activities during development is crucial to test this idea directly. In this study, we employ two metabolic biosensors to track the dynamics of pyruvate and oxidative phosphorylation (Oxphos) during the early embryogenesis of the sea urchin. A pyruvate sensor, PyronicSF, shows the signal enrichment on the mitotic apparatus, which is consistent with the localization patterns of the corresponding enzyme, pyruvate kinase (PKM). The addition of pyruvate increases the PyronicSF signal, while PKM knockdown decreases its signal, responding to the pyruvate level in the cell. Similarly, a ratio-metric sensor, Grx-roGFP, that reads the redox potential of the cell responds to DTT and H2O2, the known reducer and inducer of Oxphos. These observations suggest that these metabolic biosensors faithfully reflect the metabolic status in the cell during embryogenesis. The time-lapse imaging of these biosensors suggests that pyruvate and Oxphos levels change both spatially and temporarily during embryonic development. Pyruvate level is increased first in micromeres compared to other blastomeres at the 16-cell stage and remains high in ectoderm while decreasing in endomesoderm during gastrulation. In contrast, the Oxphos signal first decreases in micromeres at the 16-cell stage, while it increases in the endomesoderm during gastrulation, showing the opposite trend of the pyruvate signal. These results suggest that metabolic regulation is indeed both temporally and spatially dynamic during embryogenesis, and these biosensors are a valuable tool to monitor metabolic activities in real-time in developing embryos.