Structural Maintenance Of Chromosomes 3 Research Articles

Yin Yang 1 regulates cohesin complex protein SMC3 in mouse hematopoietic stem cells

Yin Yang 1 (YY1) and Structural Maintenance of Chromosomes 3 (SMC3) are two critical chromatin structural factors that mediate long-distance enhancer-promoter interactions and promote developmentally regulated changes in chromatin architecture in hematopoietic stem/progenitor cells (HSPCs). While YY1 plays critical functions in promoting hematopoietic stem cell (HSC) self-renewal and maintaining HSC quiescence, SMC3 is required for proper myeloid lineage differentiation. However, many questions remain unanswered regarding how YY1 and SMC3 interact with each other and impact hematopoiesis. We found that YY1 physically interacts with SMC3 and co-occupies with SMC3 at a large cohort of promoters genome-wide, and YY1 deficiency deregulates the genetic network governing cell metabolism. YY1 occupies the Smc3 promoter and represses SMC3 expression in HSPCs. While deletion of one Smc3 allele partially restores HSC numbers and quiescence in YY1 knockout mice, Yy1-/-Smc3+/- HSCs fail to reconstitute blood after bone marrow transplant. YY1 regulates HSC metabolic pathways and maintains proper intracellular reactive oxygen species levels in HSCs, and this regulation is independent of YY1- SMC3 axis. Our results establish a distinct YY1-SMC3 axis and its impact on HSC quiescence and metabolism.

SMC4 Loss of Function Is a New Cause of Inherited Bone Marrow Failure

Inherited bone marrow failure syndromes (IBMFS) are a rare, heterogenous group of syndromes that are characterized by cytopenias, bone marrow hypocellularity, and in many cases an increased risk of transformation to myeloid malignancy. Presentation with severe pancytopenias at birth is reported but occurs very rarely, and more often neonatal pancytopenia is attributed to congenital and acquired infections or other acquired causes. We present the case of a preterm neonate with pancytopenia from birth and bone marrow failure of no known infectious, other acquired, or genetic etiology. Antenatal findings were notable for non-immune hydrops fetalis at 30 weeks of gestation prompting delivery. The initial laboratory evaluation revealed a normocytic, reticulocytopenic, severe anemia; leukopenia with an absolute neutrophil count of 500; and severe thrombocytopenia. Viral testing, including parvovirus, rubella, herpes simplex virus, cytomegalovirus, adenovirus, and enterovirus, was negative. Additional testing, including a chromosomal microarray, mitochondrial genome sequencing, chromosome stress testing, neonatal alloimmune thrombocytopenia panel, and telomere length analysis, was non-diagnostic. Bone marrow biopsy showed a remarkably hypoplastic marrow without evidence of dysplasia or cytogenetic abnormalities. The proband underwent matched unrelated donor hematopoietic stem cell transplant, and died approximately one month later from post-transplantation complications including hepatic veno-occlusive disease, thrombotic microangiopathy, CNS and pulmonary hemorrhages, pseudomonal sepsis, and multi-organ dysfunction. Autopsy was significant for microscopic pancreatic atrophy with lipomatous hypertrophy and osteopenia. The proband and parents underwent clinical exome testing which was non-diagnostic and then consented to research reanalysis of the exome data. Research reanalysis identified the infant was compound heterozygous for predicted deleterious variants in the Structural Maintenance of Chromosomes 4 gene (SMC4), inherited in trans from each unaffected parent (c.2478_2479ins10 splice site variant predicted to alter splicing and c.T591G; p.Y197X). Germline variants in SMC4 have not been reported as a cause of human disease; however, somatic variants are observed in several cancers including in acute myeloid leukemia (AML). SMC4 is a highly conserved protein that forms a heterodimer with Structural Maintenance of Chromosomes 2 (SMC2) in the condensin II protein complex. This complex is important for chromosome condensation, cell division, and DNA repair. Within hematopoietic tissue, SMC4 expression is higher in hematopoietic stem and progenitor cells when compared with mature lineage cells. Given the predicted loss of function from both SMC4 variants, we performed RNAseq on proband and control fibroblasts. This showed a roughly 10-fold decrease in total SMC4 transcript levels (Figure 1A). A significant proportion of the transcript present was comprised of an aberrantly spliced transcript characterized by exon 15 skipping. We therefore hypothesized that loss of SMC4 expression leads to a cell intrinsic defect in hematopoiesis. To test this hypothesis, we used CRISPR-Cas9 gene editing to generate knockout of SMC4 in human cord blood CD34+ hematopoietic stem/progenitor cells (HSPCs) before culturing cells in an all-colony forming unit (CFU) assay. Using two independent small guide RNAs, we were able to achieve approximately 80% knock-down. After 14 days in culture, we observed a striking decrease in CFUs when compared with controls, though the composition of colony types was relatively unchanged (Figure 1B). Using next-generation sequencing, we observed a significant decrease in remaining SMC4 genome edits at the end of the culture period, suggesting a relative disadvantage of SMC4-edited cells for survival and/or proliferation. In summary, we describe a preterm infant with congenital bone marrow failure without an identifiable cause and link this phenotype to biallelic loss-of-function variants in SMC4. This is the first study identifying SMC4 as a novel gene that causes inherited bone marrow failure, and further experiments are underway to validate this finding.

Disruption of CDK7 signaling leads to catastrophic chromosomal instability coupled with a loss of condensin-mediated chromatin compaction

Chromatin organization is highly dynamic and modulates DNA replication, transcription, and chromosome segregation. Condensin is essential for chromosome assembly during mitosis and meiosis, as well as maintenance of chromosome structure during interphase. While it is well established that sustained condensin expression is necessary to ensure chromosome stability, the mechanisms that control its expression are not yet known. Herein, we report that disruption of cyclin-dependent kinase 7 (CDK7), the core catalytic subunit of CDK-activating kinase, leads to reduced transcription of several condensin subunits, including structural maintenance of chromosomes 2 (SMC2). Live and static microscopy revealed that inhibiting CDK7 signaling prolongs mitosis and induces chromatin bridge formation, DNA double-strand breaks, and abnormal nuclear features, all of which are indicative of mitotic catastrophe and chromosome instability. Affirming the importance of condensin regulation by CDK7, genetic suppression of the expression of SMC2, a core subunit of this complex, phenocopies CDK7 inhibition. Moreover, analysis of genome-wide chromatin conformation using Hi-C revealed that sustained activity of CDK7 is necessary to maintain chromatin sublooping, a function that is ascribed to condensin. Notably, the regulation of condensin subunit gene expression is independent of superenhancers. Together, these studies reveal a new role for CDK7 in sustaining chromatin configuration by ensuring the expression of condensin genes, including SMC2.

Identification of POLQ as a key gene in cervical cancer progression using integrated bioinformatics analysis and experimental validation.

As the most common gynecologic malignancy worldwide, cervical cancer (CC) is a serious hazard to health. Therefore, the present study aimed to identify the key genes in CC progression using integrated bioinformatics analysis and experimental validation. The mRNA microarray GSE63514 and microRNA (miRNA) microarray GSE86100 were obtained from the Gene Expression Omnibus database, and the differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) in the progression of CC were identified. Thereafter, GO and KEGG functional enrichment analysis, protein‑protein interaction (PPI) network and significant subnetworks construction, and miRNA‑target regulatory network construction were performed. Based on the results of integrated bioinformatics analysis, the DEGs structural maintenance of chromosomes 4 (SMC4), ATPase family, AAA domain‑containing 2 (ATAD2) and DNA polymerase θ (POLQ) were identified as hub genes in the PPI network and were involved in the first significant subnetwork. In addition, these DEGs were predicted to be regulated by miR‑106B, miR‑17‑5P, miR‑20A and miR‑20B, which were identified as DEMs. Of note, SMC4 and ATAD2 are tumor‑promotors in CC. In the present study, small interfering (si)RNAs were used to knock down POLQ expression. Cell Counting Kit‑8, Transwell, cell cycle and apoptosis analyses revealed that the downregulation of POLQ restrained cell proliferation, migration and invasion, and promoted apoptosis and the arrest of the cell cycle in the G2 phase. In conclusion, POLQ, which may have a close interaction with SMC4 and ATAD2, may serve a vital role in the progression of CC.

Association of SMC4 with prognosis and immune infiltration of sarcoma.

This study was performed to explore the prognostic relevance of structural maintenance of chromosomes 4 (SMC4) in pan-cancer and explore the association between SMC4 and immune infiltration of sarcoma. Elevated expression of SMC4 was detected in cancer tissues compared to normal tissue, which was confirmed in synovial sarcoma tissues with immunohistochemistry (IHC). Additionally, higher expression of SMC4 was connected to worse outcomes of sarcoma, gastric cancer, breast cancer, liver cancer or ovarian cancer. Moreover, SMC4 was positively connected to immune cell infiltrates in sarcoma. In addition, infiltrating immune cell markers including monocyte, TAM, M1 and M2 presented different SMC4-associated immune infiltration patterns. The results from our study showed that SMC4 was positively related to the prognosis and immunological status of sarcoma. SMC4 could be a potential biomarker for prognosis and immune cell infiltrates in sarcoma. Several databases including ONCOMINE, GEPIA, and Kaplan-Meier Plotter were adopted to explore the expression pattern of SMC4 in sarcoma, which was confirmed by IHC. The GEPIA and TIMER datasets were adopted to investigate the associations between SMC4 and prognosis in various cancers, especially in sarcoma.

Faecal Proteomics and Functional Analysis of Equine Melanocytic Neoplasm in Grey Horses.

Equine melanocytic neoplasm (EMN) is a common disease in older grey horses. The purpose of this study was to examine the potential proteins throughout EMN stages from faecal proteomic outlining using functional analysis. Faecal samples were collected from the rectum of 25 grey horses divided into three groups; normal group without EMN (n = 10), mild EMN (n = 6) and severe EMN (n = 9). Based on the results, 5910 annotated proteins out of 8509 total proteins were assessed from proteomic profiling. We observed differentially expressed proteins (DEPs) between the normal group and the EMN group, and 109 significant proteins were obtained, of which 28 and 81 were involved in metabolic and non-metabolic functions, respectively. We found 10 proteins that play a key role in lipid metabolism, affecting the tumour microenvironment and, consequently, melanoma progression. Interestingly, FOSL1 (FOS like 1, AP-1 transcription factor subunit) was considered as a potential highly expressed protein in a mild EMN group involved in melanocytes cell and related melanoma. Diacylglycerol kinase (DGKB), TGc domain-containing protein (Tgm2), structural maintenance of chromosomes 4 (SMC4) and mastermind-like transcriptional coactivator 2 (MAML2) were related to lipid metabolism, facilitating melanoma development in the severe-EMN group. In conclusion, these potential proteins can be used as candidate biomarkers for the monitoring of early EMN, the development of EMN, further prevention and treatment.

Abstract P2-06-02: The condensin core subunit, SMC2 (structural maintenance of chromosomes 2), is necessary for the growth and genomic stability of triple negative breast cancer cells

Abstract Chromosomal instability (CIN) is a characteristic of many cancers that contributes to a tumor cell’saccumulation of genetic defects including mutations, copy number alterations, and aneuploidy.By promoting intratumoral heterogeneity and genetic diversity, CIN can confer a selectiveadvantage to tumor cells and promote cancer progression. Triple Negative Breast Cancers(TNBCs) typically have high rates of CIN, and this contributes to disease aggressiveness andpoor patient outcomes. While basal levels of CIN contribute to cancer progression, CIN can beelevated to intolerable levels to induce mitotic catastrophe or cell death that occurs during, orimmediately following, mitosis. Discovering proteins necessary for cells to maintain basal levelsof CIN that can then be leveraged to induce mitotic catastrophe should reveal vulnerabilities thatare therapeutically targetable. In this regard, we have identified Structural Maintenance ofChromosomes 2 (SMC2) as a modulator of CIN in TNBC. SMC2 is a core member of condensin,a complex which is largely known for its role in maintaining chromosome architecture. SMC2 hasalso recently been implicated in the regulation of transcription, suggesting that this enzyme maylie at the interface of transcription and chromatin configuration. We hypothesize that TNBC cellsrely on SMC2 to control CIN through two routes: chromatin organization and transcription ofoncogenes and cell identity genes. To begin to test this hypothesis, we assessed the impact ofSMC2 silencing on TNBC cell growth in multiple cell lines. While reducing SMC2 levels initiallyincreases proliferation, SMC2 is required for long term TNBC cell viability and proper progressionthrough the cell cycle. Shortly following SMC2 suppression, TNBC cells display an increase inCIN phenotypes including multinucleation, micronucleation, and dysmorphic nucleation, as wellas DNA double strand breaks. These defects accumulate to an excessive level that ultimatelyinduces cell death. Notably, SMC2 is overexpressed in a subset of TNBC patient tumors and thisoverexpression is associated with an increased number of mutations, copy number alterations,and aneuploidy, as well as worse patient outcomes. Together, these results indicate that SMC2regulates CIN in TNBC. Given its function as an ATPase, we conclude that SMC2 is a potentialtarget for therapeutic development for the treatment of TNBC, a disease with limited therapeuticoptions. Current studies are focused on discovering the mechanisms by which SMC2 regulatesCIN in TNBC. Citation Format: Jessica Ventura, Bryan Webb, Ruth Keri. The condensin core subunit, SMC2 (structural maintenance of chromosomes 2), is necessary for the growth and genomic stability of triple negative breast cancer cells [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-06-02.

Functions of SMC2 in the Development of Zebrafish Liver.

SMC2 (structural maintenance of chromosomes 2) is the core subunit of condensins, which play a central role in chromosome organization and segregation. However, the functions of SMC2 in embryonic development remain poorly understood, due to the embryonic lethality of homozygous SMC2−/− mice. Herein, we explored the roles of SMC2 in the liver development of zebrafish. The depletion of SMC2, with the CRISPR/Cas9-dependent gene knockout approach, led to a small liver phenotype. The specification of hepatoblasts was unaffected. Mechanistically, extensive apoptosis occurred in the liver of SMC2 mutants, which was mainly associated with the activation of the p53-dependent apoptotic pathway. Moreover, an aberrant activation of a series of apoptotic pathways in SMC2 mutants was involved in the defective chromosome segregation and subsequent DNA damage. Therefore, our findings demonstrate that SMC2 is necessary for zebrafish liver development.

SMC4 knockdown inhibits malignant biological behaviors of endometrial cancer cells by regulation of FoxO1 activity

Structural maintenance of chromosomes 4 (SMC4) has an important role in chromosome condensation and segregation, which is involved in regulating multiple tumor development. However, the role of SMC4 in endometrial cancer is uncertain. The expression and prognostic value of SMC4 were predicted by UALCAN, Gene Expression Omnibus (GEO), The Human Protein Atlas and Kaplan Meier plotter tools. SMC4-related genes were analyzed by LinkedOmics, Gene Ontology (GO) annotations, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Forkhead box protein O1 (FoxO1) activity was suppressed by AS1842856 (AS). SMC4, Ki67, B-cell lymphoma-2(Bcl-2), Bcl-2 associated X protein (Bax), FoxO1, phosphorylated FoxO1 (p-FoxO1), and p27 protein levels were detected by Western blotting. Cell proliferation was detected using Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2′-deoxyuridine (EdU) analyses. Cell apoptosis was measured using TUNEL analysis. SMC4 abundance was increased in endometrial cancer, and predicted a worse overall survival. SMC4 knockdown repressed proliferative ability of endometrial cancer cells and promoted cell apoptosis. SMC4 knockdown promoted FoxO1 transactivation by decreasing its phosphorylated level. Addition of AS inhibited FoxO1 activity by increasing the phosphorylated level of FoxO1. The inhibition of FoxO1 activity reversed the effect of SMC4 silencing on cell proliferation and apoptosis. In conclusion, SMC4 silencing restrained cell proliferation and facilitated apoptosis in endometrial cancer via regulating FoxO1 activity.

Overexpression of SMC4 predicts a poor prognosis in cervical cancer and facilitates cancer cell malignancy phenotype by activating NF-κB pathway.

Cervical cancer is one of the leading female malignancy tumors worldwide. Structural maintenance of chromosomes 4 (SMC4), a member of the SMC family, is associated with cancer pathogenesis and progression. However, the role of SMC4 in cervical cancer is still unclear. In the study, SMC4 was increased in cervical cancer tissues compared with adjacent normal tissues. The SMC4 knockdown and overexpression were performed in cervical cancer cells. SMC4 knockdown inhibited cell proliferation, colony formation, cell migration and invasion, and suppressed epithelial-mesenchymal transition (EMT). Conversely, SMC4 overexpression exerted opposite effects. Moreover, SMC4 knockdown down-regulated stem cell markers, reduced the capacity of spheroid formation and inactivated NF-κB pathway. SMC4 overexpression contributed to stem cell markers, and stimulated spheroid formation and NF-κB pathway activation. Additionally, BAY11-7082 (an NF-κB inhibitor) alleviated the SMC4-mediated the effects in cervical cancer cells. In conclusion, these findings demonstrated that SMC4 overexpression facilitated the development of cervical cancer cells by activating NF-κBpathway, which provides a new therapeutic target for patients with cervical cancer.

Evolution, Expression and Meiotic Behavior of Genes Involved in Chromosome Segregation of Monotremes.

Chromosome segregation at mitosis and meiosis is a highly dynamic and tightly regulated process that involves a large number of components. Due to the fundamental nature of chromosome segregation, many genes involved in this process are evolutionarily highly conserved, but duplications and functional diversification has occurred in various lineages. In order to better understand the evolution of genes involved in chromosome segregation in mammals, we analyzed some of the key components in the basal mammalian lineage of egg-laying mammals. The chromosome passenger complex is a multiprotein complex central to chromosome segregation during both mitosis and meiosis. It consists of survivin, borealin, inner centromere protein, and Aurora kinase B or C. We confirm the absence of Aurora kinase C in marsupials and show its absence in both platypus and echidna, which supports the current model of the evolution of Aurora kinases. High expression of AURKBC, an ancestor of AURKB and AURKC present in monotremes, suggests that this gene is performing all necessary meiotic functions in monotremes. Other genes of the chromosome passenger complex complex are present and conserved in monotremes, suggesting that their function has been preserved in mammals. Cohesins are another family of genes that are of vital importance for chromosome cohesion and segregation at mitosis and meiosis. Previous work has demonstrated an accumulation and differential loading of structural maintenance of chromosomes 3 (SMC3) on the platypus sex chromosome complex at meiotic prophase I. We investigated if a similar accumulation occurs in the echidna during meiosis I. In contrast to platypus, SMC3 was only found on the synaptonemal complex in echidna. This indicates that the specific distribution of SMC3 on the sex chromosome complex may have evolved specifically in platypus.

Transcriptome Characterization of Short Distance Transport Stress in Beef Cattle Blood.

The transportation is a crucial phase in beef cattle industry, and the annual losses caused by beef cattle transport stress are substantial. Several studies have described the effect of long distance transportation stress on animal health, such as disorder in nervous, endocrine, immune, and metabolic system. However, molecular mechanisms underlying short distance transportation stress is still poorly understood. Present study aims to investigate the effect of short distance transportation by measuring the hematological indices and transcriptomic analysis. In this study, a total 10 Qinchuan cattle were used to compare the molecular characteristics of blood before and after transportation. We have found that a stress-related marker “white blood cell count (WBC)” increased significantly after transportation. The decrease in triglyceride (TG), cholestenone (CHO), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) showed that energy expenditure was increased after transportation, but not enough to activate fatty decomposition. Intriguingly, the decrease of malondialdehyde (MDA) showed that cattle were more resilience to oxidative stress. The RNA-seq showed that 1,092 differentially expressed genes (DEGs) were found (329 up-regulated and 763 down-regulated) between group before and group after. The GO and KEGG enrichment showed that the metabolic pathway and B cell function related pathways were enriched. Furthermore, median absolute deviation (MAD) top 5,000 genes were used to construct a co-expression network by weighted correlation network analysis (WGCNA), and 11 independent modules were identified. Combing with protein-protein interaction (PPI) analysis, the verification of quantitative real-time PCR (qPCR) and the correlation of B cell function, structural maintenance of chromosomes 3 (SMC3), jun proto-oncogene (JUN), and C-X-C motif chemokine ligand 10 (CXCL10) were suggested as potential molecular markers in identification of short distance transportation. Collectively, the blood RNA-seq analysis and WGCNA indicated that the disorder of B cell differentiation, proliferation, survival, and apoptosis were the potential molecular mechanism in short distance transportation stress. In conclusion, our results provide the novel insight about potential biomarkers for short distance transportation stress, which may serve as for diagnosing and preventing this condition in beef industry.

Identification of Potential Hub Genes and Signal Pathways Promoting the Distinct Biological Features of Cord Blood-Derived Endothelial Progenitor Cells Via Bioinformatics.

Background: Numerous studies, ranging from the alleviation of tissue ischemia to the assessment of cancer prognosis, have demonstrated the fundamental biological differences between human umbilical cord blood-derived endothelial progenitor cells (CB-EPCs) and adult peripheral blood-derived endothelial progenitor cells (PB-EPCs). However, the underlying molecular mechanisms that produce these differences are not clear.The purpose of this study was to identify potential hub genes, key protein interactive networks, and correlated signal pathways unique to CB-EPC biology via bioinformatic methods. Materials and Methods: We selected the microarray dataset GSE39763 and identified the differentially expressed genes (DEGs) using the "limma" package in the RStudio software. These DEGs were annotated by gene ontology enrichment analyses and signal pathway analyses. A protein-protein interaction (PPI) analysis was then performed to construct PPI networks and identify a hub protein module. We further validated candidate DEGs from the selected module in the gene expression profiling interactive analysis (GEPIA) database because the DEGs were enriched in cancer pathways. Results: Setting an adjusted p-value <0.01 and |Log2 fold change (FC)| ≥ 2 as cutoff criteria, a total of 346 DEGs, including 314 upregulated genes and 32 downregulated genes in CB-EPCs, were identified. Expression of the genes encoding the AT-Hook Containing Transcription Factor 1 (AHCTF1), the Cancer Susceptibility Candidate 5 (CASC5), the Centromere Protein C (CENPC), the Centromere Protein E (CENPE), the Centromere Protein F (CENPF), the NUF2 Component of NDC80 Kinetochore Complex (NUF2), the RAN-Binding Protein 2 (RANBP2), the Shugoshin-like 2 (SGOL2), the Structural Maintenance of Chromosomes 3 (SMC3), and the Spindle Apparatus Coiled-Coil Protein 1 (SPDL1) proteins were specifically associated with CB-EPCs. Except for CENPC, the other nine genes' expression are all associated with a poorer overall survival rate in cancers. The expression levels of the CENPF and NUF2 genes in tumor patients were significantly higher than those in the controls. Conclusion: The CB-EPCs express genes with greater potential for proliferation and increased migration compared to PB-EPCs; in this regard they are similar to cancer cells.

Persistent DNA Damage and Senescence in the Placenta Impacts Developmental Outcomes of Embryos.

Cohesin is an evolutionarily conserved chromosome-associated protein complex essential for chromosome segregation, gene expression, and repair of DNA damage. Mutations that affect this complex cause the human developmental disorder Cornelia de Lange syndrome (CdLS), thought to arise from defective embryonic transcription. We establish a significant role for placental defects in the development of CdLS mouse embryos (Nipbl and Hdac8). Placenta is a naturally senescent tissue; we demonstrate that persistent DNA damage potentiates senescence and activates cytokine signaling. Mutant embryo developmental outcomes are significantly improved in the context of a wild-type placenta or by genetically restricting cytokine signaling. Our study highlights that cohesin is required for maintaining ploidy and the repair of spontaneous DNA damage in placental cells, suggesting that genotoxic stress and ensuing placental senescence and cytokine production could represent a broad theme in embryo health and viability.

The condensin subunits SMC2 and SMC4 interact for correct condensation and segregation of mitotic maize chromosomes.

Structural Maintenance of Chromosomes 2 (SMC2) and Structural Maintenance of Chromosomes 4 (SMC4) are the core components of the condensin complexes, which are required for chromosome assembly and faithful segregation during cell division. Because of the crucial functions of both proteins in cell division, much work has been done in various vertebrates, but little information is known about their roles in plants. Here, we identified ZmSMC2 and ZmSMC4 in maize (Zea mays) and confirmed that ZmSMC2 associates with ZmSMC4 via their hinge domains. Immunostaining revealed that both proteins showed dynamic localization during mitosis. ZmSMC2 and ZmSMC4 are essential for proper chromosome segregation and for H3 phosphorylation at Serine 10 (H3S10ph) at pericentromeres during mitotic division. The loss of function of ZmSMC2 and ZmSMC4 enlarges mitotic chromosome volume and impairs sister chromatid separation to the opposite poles. Taken together, these findings confirm and extend the coordinated role of ZmSMC2 and ZmSMC4 in maintenance of normal chromosome architecture and accurate segregation during mitosis.

Structural maintenance of chromosomes 2 is identified as an oncogene in bladder cancer in vitro and in vivo.

Taurine upregulated gene 1 (TUG1) has been found to promote bladder cancer cell growth in our recent research. In this study, TUG1-depleted bladder cancer cells were used to identify potent players in bladder cancer. Human gene expression arrays were used for transcriptome profiling of TUG1-depleted bladder cancer cells. Cell proliferation was analyzed by MTT assay. Cell apoptosis and cell cycle were analyzed by flow cytometry. Colony formation assay was used to observe the changes of colony formation rates. Xenograft formation assay was performed in nude mice. Immunohistochemical staining was used to test the gene expression levels in tissues from bladder cancer patients. We found that deregulated genes were strongly enriched in cell cycle or pathways in cancer in TUG1-depleted bladder cancer cells. Structural maintenance of chromosomes 2 (SMC2) was inhibited after TUG1 knockdown. The depletion of TUG1 or SMC2 led to G2/M phase arrest in bladder cancer cells. SMC2 depletion inhibited bladder cancer cell proliferation, promoted apoptosis, decreased colony formation, and reduced tumor growth in xenograft nude mice. Overexpression of SMC2 restored the growth of TUG1-depleted cells. The expression levels of SMC2 were higher in human bladder cancer tissues than that in paired normal tissues. Our data suggest that SMC2 is an oncogene in bladder cancer and depletion of SMC2 might have potential therapeutical significance in bladder cancer.

Hydrogen gas inhibits lung cancer progression through targeting SMC3

Lung cancer is one of the most common lethal malignancies in the globe. The patients’ prognoses are dim due to its high metastatic potential and drug resistance. Therefore, in the present study, we aim to find a more potent therapeutic approach for lung cancer. We mainly explored the function of hydrogen gas (H2) on cell viability, apoptosis, migration and invasion in lung cancer cell lines A549 and H1975 by CCK-8, flow cytometry, wound healing and transwell assays, respectively. We used RNA-seq, qPCR and western blotting to detect the different expression genes (DEGs) between H2 group and control group to find the gene related to chromosome condensation. Besides, we confirmed the structural maintenance of chromosomes 3 (SMC3) and H2 on the progression of lung cancer in vitro and vivo. Results showed that H2 inhibited cell viability, migration and invasion, and catalyzed cell apoptosis and H2 induced A549 and H1975 cells G2/M arrest. Besides, H2 down-regulated the expression of NIBPL, SMC3, SMC5 and SMC6, and also reduced the expression of Cyclin D1, CDK4 and CDK6. H2 translocated the subcellular location of SMC3 during cell division and decreased its stability and increased its ubiquitination in both A549 and H1975 cells. In addition, inhibition of the proliferation, migration and invasion and promotion of the apoptosis of A549 and H1975 cells induced by H2 were all abolished when overexpressed SMC3 in the presence of H2. Animal experimental assay demonstrated that the tumor weight in H2 group was significantly smaller than that in control group, but was bigger than cis-platinum group. The expression of Ki-67, VEGF and SMC3 were decreased when mice were treated with H2 or cis-platinum, especially for cis-platinum. All data suggested that H2 inhibited lung cancer progression through down-regulating SMC3, a regulator for chromosome condensation, which provided a new method for the treatment of lung cancer.

The Novel HDAC8 Inhibitor WK2-16 Attenuates Lipopolysaccharide-Activated Matrix Metalloproteinase-9 Expression in Human Monocytic Cells and Improves Hypercytokinemia In Vivo.

Dysregulated human monocytes/macrophages can synthesize and secrete matrix metalloproteinases (MMPs), which play important roles in the progression of sepsis. In this study, we investigated the effects and mechanism of a novel histone deacetylase (HDAC8) inhibitor, (E)-N-hydroxy-4-methoxy-2-(biphenyl-4-yl)cinnamide (WK2-16), on MMP-9 production and activation in stimulated human monocytic THP-1 cells. Our results demonstrated that the acetylation level of structural maintenance of chromosomes 3 (SMC3) was up-regulated by WK2-16 in THP-1 cells. Consistently, an in vitro enzyme study demonstrated that WK2-16 selectively inhibited HDAC8 activity. Moreover, the WK2-16 concentration dependently suppressed MMP-9-mediated gelatinolysis induced by tumor necrosis factor-α (TNF-α) or lipopolysaccharide (LPS). Additionally, WK2-16 significantly inhibited both MMP-9 protein and mRNA expression without cellular toxicity. Nevertheless, WK2-16 suppressed the extracellular levels of interleukin (IL)-6 from LPS-stimulated THP-1 cells. For the signaling studies, WK2-16 had no effect on LPS/TLR4 downstream signaling pathways, such as the NF-κB and ERK/JNK/P38 MAPK pathways. On the other hand, WK2-16 enhanced the recruitment of acetylated Yin Yang 1 (YY1) with HDAC1. Finally, in vivo studies indicated that WK2-16 could reduce the serum levels of TNF-α and IL-6 in endotoxemic mice. These results suggested that HDAC8 inhibition might provide a novel therapeutic strategy of hypercytokinemia in sepsis.

Overexpression of SMC4 activates TGFβ/Smad signaling and promotes aggressive phenotype in glioma cells

Overexpression of structural maintenance of chromosomes 4 (SMC4) has been reported to be involved in tumor cell growth, migration and invasion, and to be correlated with poor prognosis of cancer patient. However, its clinical significance and biological role in glioma remain unknown. Herein, we found that SMC4 expression at both mRNA and protein level was markedly increased in glioma cells and clinical tissues and that it correlated with poor prognosis. SMC4 overexpression markedly promoted the glioma cell proliferation rate and migration and invasive capability in vitro and in vivo, whereas SMC4 downregulation reduced it. Moreover, the transforming growth factor β (TGFβ)/Smad signaling pathway, which was activated in SMC4-transduced glioma cells and inhibited in SMC4-silenced glioma cells, contributed to SMC4-mediated glioma cell aggressiveness. Our results provide new insight into the oncofunction of SMC4 and the mechanism by which the TGFβ/Smad pathway is hyperactivated in gliomas, indicating that SMC4 is a valuable prognostic factor and a potential therapeutic target in gliomas.

Structural maintenance of chromosomes 4 is a predictor of survival and a novel therapeutic target in colorectal cancer.

Structural maintenance of chromosomes 4 (SMC-4) is a chromosomal ATPase which plays an important role in regulate chromosome assembly and segregation. However, the role of SMC-4 in the incidence of malignancies, especially colorectal cancer is still poorly understood. We here used quantitative PCR and Western blot analysis to examine SMC-4 mRNA and protein levels in primary colorectal cancer and paired normal colonic mucosa. SMC-4 clinicopathological significance was assessed by immunohistochemical staining in a tissue microarray (TMA) in which 118 cases of primary colorectal cancer were paired with noncancerous tissue. The biological function of SMC-4 knockdown was measured by CCK8 and plate colony formation assays. Fluorescence detection has been used to detect cell cycling and apoptosis. SMC-4 expression was significantly higher in colorectal cancer and associated with T stage, N stage, AJCC stage and differentiation. Knockdown of SMC-4 expression significantly suppressed the proliferation of cancer cells and degraded its malignant degree. Our clinical and experimental data suggest that SMC-4 may contribute to the progression of colorectal carcinogenesis. Our study provides a new therapeutic target for colorectal cancer treatment.