Roles of the CSE1L-mediated nuclear import pathway in epigenetic silencing

Unveiling the therapeutic potential of IHMT-337 in glioma treatment: targeting the EZH2-SLC12A5 axis

Glioma is the most common malignant tumor of the central nervous system, with EZH2 playing a crucial regulatory role. This study further explores the abnormal expression of EZH2 and its mechanisms in regulating glioma progression. Additionally, it was found that IHMT-337 can potentially be a therapeutic agent for glioma. The prognosis, expression, and localization of EZH2 were determined using bioinformatics, IHC staining, Western blot (WB) analysis, and immunofluorescence (IF) localization. The effects of EZH2 on cell function were assessed using CCK-8 assays, Transwell assays, and wound healing assays. Public databases and RT-qPCR were utilized to identify downstream targets. The mechanisms regulating these downstream targets were elucidated using MS-PCR and WB analysis. The efficacy of IHMT-337 was demonstrated through IC50 measurements, WB analysis, and RT-qPCR. The effects of IHMT-337 on glioma cells in vitro were evaluated using Transwell assays, EdU incorporation assays, and flow cytometry. The potential of IHMT-337 as a treatment for glioma was assessed using a blood-brain barrier (BBB) model and an orthotopic glioma model. Our research confirms significantly elevated EZH2 expression in gliomas, correlating with patient prognosis. EZH2 facilitates glioma proliferation, migration, and invasion alongside promoting SLC12A5 DNA methylation. By regulating SLC12A5 expression, EZH2 activates the WNK1-OSR1-NKCC1 pathway, enhancing its interaction with ERM to promote glioma migration. IHMT-337 targets EZH2 in vitro to inhibit WNK1 activation, thereby suppressing glioma cell migration. Additionally, it inhibits cell proliferation and arrests the cell cycle. IHMT-337 has the potential to cross the BBB and has successfully inhibited glioma progression in vivo. This study expands our understanding of the EZH2-SLC12A5 axis in gliomas, laying a new foundation for the clinical translation of IHMT-337 and offering new insights for precision glioma therapy.

Nuclear transport proteins: structure, function, and disease relevance

Proper subcellular localization is crucial for the functioning of biomacromolecules, including proteins and RNAs. Nuclear transport is a fundamental cellular process that regulates the localization of many macromolecules within the nuclear or cytoplasmic compartments. In humans, approximately 60 proteins are involved in nuclear transport, including nucleoporins that form membrane-embedded nuclear pore complexes, karyopherins that transport cargoes through these complexes, and Ran system proteins that ensure directed and rapid transport. Many of these nuclear transport proteins play additional and essential roles in mitosis, biomolecular condensation, and gene transcription. Dysregulation of nuclear transport is linked to major human diseases such as cancer, neurodegenerative diseases, and viral infections. Selinexor (KPT-330), an inhibitor targeting the nuclear export factor XPO1 (also known as CRM1), was approved in 2019 to treat two types of blood cancers, and dozens of clinical trials of are ongoing. This review summarizes approximately three decades of research data in this field but focuses on the structure and function of individual nuclear transport proteins from recent studies, providing a cutting-edge and holistic view on the role of nuclear transport proteins in health and disease. In-depth knowledge of this rapidly evolving field has the potential to bring new insights into fundamental biology, pathogenic mechanisms, and therapeutic approaches.

CSE1L is a negative regulator of the RB-DREAM pathway in p53 wild-type NSCLC and can be targeted using an HDAC1/2 inhibitor

P53 represses transcription by activating p21 expression and promoting formation of RB1-E2F1 and RBL1/RBL2-DREAM transcription repressor complexes. The DREAM complex is composed of DP1, RB-family proteins RBL1 or RBL2 (p107/p130), E2F4/5, and MuvB. We recently reported RBL2-DREAM contributes to improved therapy responses in p53 wild-type NSCLC cells and improved outcomes in NSCLC patients whose tumors express wild-type p53. In the current study we identified CSE1L as a novel inhibitor of the RBL2-DREAM pathway and target to activate RBL2-DREAM in NSCLC cells. CSE1L is an oncoprotein that maintains repression of genes that can be reactivated by HDAC inhibitors. Mocetinostat is a HDAC inhibitor in clinical trials with selectivity against HDACs 1 and 2. Knockdown of CSE1L in NSCLC cells or treatment with mocetinostat increased p21, activated RB1 and RBL2, repressed DREAM target genes, and induced toxicity in a manner that required wild-type p53. Lastly, we found high levels of CSE1L and specific DREAM-target genes are candidate markers to identify p53 wild-type NSCLCs most responsive to mocetinostat. Thus, we identified CSE1L as a critical negative regulator of the RB-DREAM pathway in p53 wild-type NSCLC that can be indirectly targeted with HDAC1/2 inhibitors (mocetinostat) in current clinical trials. High expression of CSE1L and DREAM target genes could serve as a biomarker to identify p53 wild-type NSCLCs most responsive to this HDAC1/2 inhibitor.

Genome-wide analysis of epigenetic and transcriptional changes in the pathogenesis of RGSV in rice

Rice grassy stunt virus (RGSV), a typical negative single-stranded RNA virus, invades rice and generates several disease signs, including dwarfing, tillering, and sterility. Previous research has revealed that RGSV-encoded proteins can force the host's ubiquitin-proteasome system to utilize them for viral pathogenesis. However, most of the studies were limited to a single omics level and lacked multidimensional data collection and correlation analysis on the mechanisms of RGSV-rice interactions. Here, we performed a comprehensive association analysis of genome-wide methylation sequencing, transcriptome sequencing, and histone H3K9me3 modification in RGSV-infested as well as non-infested rice leaves, and the levels of all three cytosine contexts (CG, CHG and CHH) were found to be slightly lower in RGSV-infected rice leaves than in normal rice. Large proportions of DMRs were distributed in the promoter and intergenic regions, and most DMRs were enriched in the CHH context, where the number of CHH hypo-DMRs was almost twice as high as that of hyper-DMRs. Among the genes with down-regulated expression and hypermethylation, we analyzed and identified 11 transcripts involved in fertility, plant height and tillering, and among the transcribed up-regulated and hypermethylated genes, we excavated 7 transcripts related to fertility, plant height and tillering. By analyzing the changes of histone H3K9me3 modification before and after virus infestation, we found that the distribution of H3K9me3 modification in the whole rice genome was prevalent, mainly concentrated in the gene promoter and gene body regions, which was distinctly different from the characteristics of animals. Combined with transcriptomic data, H3K9me3 mark was found to favor targeting highly expressed genes. After RGSV infection, H3K9me3 modifications in several regions of CTK and BR hormone signaling-related genes were altered, providing important targets for subsequent studies.

Unconventional tonicity-regulated nuclear trafficking of NFAT5 mediated by KPNB1, XPOT and RUVBL2

NFAT5 is the only known mammalian tonicity-responsive transcription factor with essential role in cellular adaptation to hypertonic stress. It is also implicated in diverse physiological and pathological processes. NFAT5 activity is tightly regulated by extracellular tonicity, but the underlying mechanisms remain elusive. We demonstrated that NFAT5 enters the nucleus via the nuclear pore complex. We found that NFAT5 utilizes a unique nuclear localization signal (NFAT5-NLS) for nuclear import. siRNA screening revealed that only karyopherin β1 (KPNB1), but not karyopherin alpha, is responsible for the nuclear import of NFAT5 via direct interaction with the NFAT5-NLS. Proteomics analysis and siRNA screening further revealed that nuclear export of NFAT5 under hypotonicity is driven by Exportin-T, where the process requires RuvB-Like AAA type ATPase 2 (RUVBL2) as an indispensable chaperone. Our findings have identified an unconventional tonicity-dependent nucleocytoplasmic trafficking pathway for NFAT5, a critical step in orchestrating rapid cellular adaptation to change in extracellular tonicity. These findings offer an opportunity for the development of novel NFAT5 targeting strategies that are potentially useful for the treatment of diseases associated with NFAT5 dysregulation.

Interfering with CSE1L/CAS inhibits tumour growth via C3 in triple-negative breast cancer

Triple‐negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. However, the treatment regimens for TNBC are limited. Chromosome segregation 1‐like (CSE1L), also called cellular apoptosis susceptibility protein (CAS), is highly expressed in breast cancer and plays a crucial role in the progression of various tumours. However, the involvement of CAS in TNBC remains elusive. In this study, we showed that the expression of CAS was higher in TNBC samples than in non‐TNBC samples in the Gene Expression Omnibus database. Knockdown of CAS inhibited MDA‐MB‐231 cell growth, migration and invasion. Further RNA‐seq analysis revealed that complement pathway activity was significantly elevated. Of note, complement component 3 (C3), the key molecule in the complement pathway, was significantly upregulated, and the expression of C3 was negatively correlated with that of CAS in breast cancer. Lower C3 expression was related to poor prognosis. Interestingly, the expression level of C3 was positively correlated with the infiltration of multiple immune cells. Taken together, our findings suggest that CAS participates in the development of TNBC through C3‐mediated immune cell suppression and might constitute a potential therapeutic target for TNBC.

Bisphenol A replacement chemicals, BPF and BPS, induce protumorigenic changes in human mammary gland organoid morphology and proteome

SignificanceBisphenol A (BPA), found in many plastic products, has weak estrogenic effects that can be harmful to human health. Thus, structurally related replacements-bisphenol S (BPS) and bisphenol F (BPF)-are coming into wider use with very few data about their biological activities. Here, we compared the effects of BPA, BPS, and BPF on human mammary organoids established from normal breast tissue. BPS disrupted organoid architecture and induced supernumerary branching. At a proteomic level, the bisphenols altered the abundance of common targets and those that were unique to each compound. The latter included proteins linked to tumor-promoting processes. These data highlighted the importance of testing the human health effects of replacements that are structurally related to chemicals of concern.

PHY34 inhibits autophagy through V-ATPase V0A2 subunit inhibition and CAS/CSE1L nuclear cargo trafficking in high grade serous ovarian cancer

PHY34 is a synthetic small molecule, inspired by a compound naturally occurring in tropical plants of the Phyllanthus genus. PHY34 was developed to have potent in vitro and in vivo anticancer activity against high grade serous ovarian cancer (HGSOC) cells. Mechanistically, PHY34 induced apoptosis in ovarian cancer cells by late-stage autophagy inhibition. Furthermore, PHY34 significantly reduced tumor burden in a xenograft model of ovarian cancer. In order to identify its molecular target/s, we undertook an unbiased approach utilizing mass spectrometry-based chemoproteomics. Protein targets from the nucleocytoplasmic transport pathway were identified from the pulldown assay with the cellular apoptosis susceptibility (CAS) protein, also known as CSE1L, representing a likely candidate protein. A tumor microarray confirmed data from mRNA expression data in public databases that CAS expression was elevated in HGSOC and correlated with worse clinical outcomes. Overexpression of CAS reduced PHY34 induced apoptosis in ovarian cancer cells based on PARP cleavage and Annexin V staining. Compounds with a diphyllin structure similar to PHY34 have been shown to inhibit the ATP6V0A2 subunit of V(vacuolar)-ATPase. Therefore, ATP6V0A2 wild-type and ATP6V0A2 V823 mutant cell lines were tested with PHY34, and it was able to induce cell death in the wild-type at 246 pM while the mutant cells were resistant up to 55.46 nM. Overall, our data demonstrate that PHY34 is a promising small molecule for cancer therapy that targets the ATP6V0A2 subunit to induce autophagy inhibition while interacting with CAS and altering nuclear localization of proteins.

A Novel Mutation in Cse1l Disrupts Brain and Eye Development with Specific Effects on Pax6 Expression

Forward genetics in the mouse continues to be a useful and unbiased approach to identifying new genes and alleles with previously unappreciated roles in mammalian development and disease. Here, we report a new mouse allele of Cse1l that was recovered from an ENU mutagenesis screen. Embryos homozygous for the anteater allele of Cse1l display a number of variable phenotypes, with craniofacial and ocular malformations being the most obvious. We provide evidence that Cse1l is the causal gene through complementation with a novel null allele of Cse1l generated by CRISPR-Cas9 editing. While the variability in the anteater phenotype was high enough to preclude a detailed molecular analysis, we demonstrate a very penetrant reduction in Pax6 levels in the developing eye along with significant ocular developmental phenotypes. The eye gene discovery tool iSyTE shows Cse1l to be significantly expressed in the lens from early eye development stages in embryos through adulthood. Cse1l has not previously been shown to be required for organogenesis as homozygosity for a null allele results in very early lethality. Future detailed studies of Cse1l function in craniofacial and neural development will be best served with a conditional allele to circumvent the variable phenotypes we report here. We suggest that human next-generation (whole genome or exome) sequencing studies yielding variants of unknown significance in CSE1L could consider these findings as part of variant analysis.

CSE1L promotes nuclear accumulation of transcriptional coactivator TAZ and enhances invasiveness of human cancer cells

The transcriptional coactivator with PDZ-binding motif (TAZ) (WWTR1) induces epithelial-mesenchymal transition and enhances drug resistance in multiple cancers. TAZ has been shown to interact with transcription factors in the nucleus, but when phosphorylated, translocates to the cytoplasm and is degraded through proteasomes. Here, we identified a compound TAZ inhibitor 4 (TI-4) that shifted TAZ localization to the cytoplasm independently of its phosphorylation. We used affinity beads to ascertain a putative target of TI-4, chromosomal segregation 1 like (CSE1L), which is known to be involved in the recycling of importin α and as a biomarker of cancer malignancy. We found that TI-4 suppressed TAZ-mediated transcription in a CSE1L-dependent manner. CSE1L overexpression increased nuclear levels of TAZ, whereas CSE1L silencing delayed its nuclear import. We also found via the in vitro coimmunoprecipitation experiments that TI-4 strengthened the interaction between CSE1L and importin α5 and blocked the binding of importin α5 to TAZ. WWTR1 silencing attenuated CSE1L-promoted colony formation, motility, and invasiveness of human lung cancer and glioblastoma cells. Conversely, CSE1L silencing blocked TAZ-promoted colony formation, motility, and invasiveness in human lung cancer and glioblastoma cells. In human cancer tissues, the expression level of CSE1L was found to correlate with nuclear levels of TAZ. These findings support that CSE1L promotes the nuclear accumulation of TAZ and enhances malignancy in cancer cells.

Nuclear export protein CSE1L interacts with P65 and promotes NSCLC growth via NF-κB/MAPK pathway

Non-small cell lung cancer (NSCLC) is characterized with high morbidity and mortality, mainly due to frequent recurrence and metastasis. However, the underlying molecular mechanisms of NSCLC tumorigenesis are largely unclear. Through data mining in the ONCOMINE and Gene Expression Omnibus (GEO) databases, the expression of CSE1L (chromosome segregation like 1 protein/CAS), an exportin, was identified to be significantly upregulated in NSCLC and positively associated with poor prognosis of patients. By use of in vitro and in vivo gain- and loss-of-function experiments, we found that CSE1L can promote NSCLC cell proliferation while inhibiting cell apoptosis. Through immunoprecipitation and mass spectrometry experiments, we demonstrated that CSE1L interacted with RELA (named as P65) and affected its location in the nucleus. Moreover, we found that one of the mechanisms by which CSE1L promotes proliferation and inhibits apoptosis is through activating the nuclear factor-κB (NF-κB)/mitogen-activated protein kinase (MAPK) signaling pathway. In summary, our findings indicated an oncogenic role of CSE1L in NSCLC tumorigenesis.

Sustained TNF-α stimulation leads to transcriptional memory that greatly enhances signal sensitivity and robustness

Transcriptional memory allows certain genes to respond to previously experienced signals more robustly. However, whether and how the key proinflammatory cytokine TNF-α mediates transcriptional memory are poorly understood. Using HEK293F cells as a model system, we report that sustained TNF-α stimulation induces transcriptional memory dependent on TET enzymes. The hypomethylated status of transcriptional regulatory regions can be inherited, facilitating NF-κB binding and more robust subsequent activation. A high initial methylation level and CpG density around κB sites are correlated with the functional potential of transcriptional memory modules. Interestingly, the CALCB gene, encoding the proven migraine therapeutic target CGRP, exhibits the best transcriptional memory. A neighboring primate-specific endogenous retrovirus stimulates more rapid, more strong, and at least 100-fold more sensitive CALCB induction in subsequent TNF-α stimulation. Our study reveals that TNF-α-mediated transcriptional memory is governed by active DNA demethylation and greatly sensitizes memory genes to much lower doses of inflammatory cues.

Genes are the instruction manuals of life and contain the information needed to build the building blocks that keep cells alive. To read these instructions, cells use specific signals that activate genes. The process, known as gene expression, is tightly controlled and for the most part, fairly stable. But gene expression can be modified in various ways.

Epigenetics is a broad term for describing reversible changes made to genes to switch them on and off. Sometimes, certain genes even develop a kind of ‘transcriptional memory’ where over time, their expression is enhanced and speeds up with repeated activation signals. But this may also have harmful effects.

For example, the signalling molecule called tumour necrosis factor α (TNF-α) is an essential part of the immune system. But it is also implicated in chronic inflammatory diseases, such as rheumatoid arthritis. In these conditions, cell signalling pathways triggering inflammation are overactive. One possibility is that TNF-α could be inducing the transcriptional memory of certain genes, amplifying their expression. But little is known about which fraction of genes exhibits transcriptional memory, and what differentiates memory genes from genes with stable expression.

Here, Zhao et al. treated cells grown in the laboratory with TNF-α to investigate its role in transcriptional memory and find out what epigenetic features might govern the process. The experiments showed that mimicking a sustained inflammation by stimulating TNF-α, triggered a transcriptional memory in some genes, and enabled them to respond to much lower levels of TNF-α on subsequent exposure.

Zhao et al. also discovered that genes tagged with methyl groups are more likely to show transcriptional memory when stimulated by TNF-α. However, they also found that these groups must be removed to consolidate any transcriptional memory.

This work shows how TNF-α influences can alter the expression of certain genes. It also suggests that transcriptional memory, stimulated by TNF-α, may be a possible mechanism underlying chronic inflammatory conditions. This could help future research in identifying more genes with transcriptional memory.

Cellular apoptosis susceptibility protein (CAS) suppresses the proliferation of breast cancer cells by upregulated cyp24a1

Breast cancer is the most common cancer in women. Although several studies demonstrated cellular apoptosis susceptibility protein (CAS) involved in the development of breast cancer, the underlying mechanisms of CAS regulating cell processes in the breast cancer remain elusive. In the present study, we explored the possible mechanism of CAS in contributing to the cell proliferation in the breast cancer cell line MCF-7. Knockdown of CAS led to the reduction of cell viability and proliferation. Furthermore, cell cycle was arrested in G0/G1 phase after knocking down CAS with the decrease of cyclinD1. In addition, RNA-seq analysis for the CAS knockdown cells demonstrated that total eleven genes were significantly altered (Fold changes > 2). Of note, the expression of cyp24a1 was dramatically increased in the shCAS cells compared to that of shNC cells as well as confirmed by quantitative real-time polymerase chain reaction (qPCR). These observations clarified the previous conflicting results on the cell fates of the breast cells regulated by CAS and provide new insight into the role of CAS in the development of breast cancer.

Epigenetics in the plant-virus interaction

Plants have developed diverse molecular mechanisms to resist viruses. RNA silencing plays a dominant role in antiviral defense. Recent studies have correlated plant antiviral silencing to epigenetic modification in genomic DNA and protein by remodeling the expression levels of coding genes. The plant host methylation level is reprogrammed in response to viral challenge. Genomes of some viruses have been implicated in the epigenetic modification via small RNA-mediated transcriptional gene silencing and post-transcriptional gene silencing. These mechanisms can be primed prior to a virus attack through methylation changes for antiviral defense. This review highlights the findings concerning the methylation changes in plant-virus interactions and demonstrates a possible direction to improve the understanding of plant host methylation regulation in response to viral infection.

Expression of cellular apoptosis susceptibility (CAS) in the human testis and testicular germ cell tumors

Testicular germ cell tumors are the most frequent malignancies found in men between 15 and 44 years old. Although cellular apoptosis susceptibility (CAS) was demonstrated to be upregulated in breast cancer and colon cancer, the expression of CAS in the human testis and testicular germ cell tumors remained elusive. In the present study, CAS-positive signals were detected in the normal testicular tissues, cancer adjacent normal testicular tissues, seminoma, yolk sac tumor, and teratoma. Interestingly, the expression level of CAS in testicular germ cell tumors (TGCTs) (but not seminoma) was significantly lower than that of human testicular tissues and cancer adjacent normal testicular tissues, suggesting that decreased CAS contributed to the progression of TGCTs. Notably, the expression of CAS in seminoma was significantly higher than that of in the non-seminomas, consistent with the results from TCGA database. Furthermore, the localization of CAS is mainly restricted in the nucleus in the lesions of normal human testicular tissue and cancer adjacent normal testicular tissue. Although the expression of CAS was not significantly different between normal testicular tissue and seminoma, CAS was more enriched in cytoplasm in seminoma compared to the normal, cancer adjacent tissue and other types of TGCTs. The current results demonstrated reduced expression of CAS in the human testicular germ cell tumors and the CAS translocation from the nuclear to cytoplasm in seminoma, thereby supporting a possible role in normal testis function and in the development of seminoma.

Stella protein facilitates DNA demethylation by disrupting the chromatin association of the RING finger-type E3 ubiquitin ligase UHRF1

Stella is a maternal gene required for oogenesis and early embryogenesis. Stella overexpression in somatic cells causes global demethylation. As we have recently shown, Stella sequesters nuclear ubiquitin-like with PHD and RING finger domains 1 (UHRF1), a RING finger-type E3 ubiquitin ligase essential for DNA methylation mediated by DNA methyltransferase 1 and triggers global demethylation. Here, we report an overexpressed mutant Stella protein without nuclear export activity surprisingly retained its ability to cause global demethylation. By combining biochemical interaction assays, isothermal titration calorimetry, immunostaining, and live-cell imaging with fluorescence recovery after photobleaching, we found that Stella disrupts UHRF1's association with chromatin by directly binding to the plant homeodomain of UHRF1 and competing for the interaction between UHRF1 and the histone H3 tail. Consistently, overexpression of Stella mutants that do not directly interact with UHRF1 fails to cause genome-wide demethylation. In the presence of nuclear Stella, UHRF1 could not bind to chromatin and exhibited increased dynamics in the nucleus. Our results indicate that Stella employs a multilayered mechanism to achieve robust UHRF1 inhibition, which involves the dissociation from chromatin and cytoplasmic sequestration of UHRF1.

The proinflammatory cytokine TNFα induces DNA demethylation-dependent and -independent activation of interleukin-32 expression

IL-32 is a cytokine involved in proinflammatory immune responses to bacterial and viral infections. However, the role of epigenetic events in the regulation of IL-32 gene expression is understudied. Here we show that IL-32 is repressed by DNA methylation in HEK293 cells. Using ChIP sequencing, locus-specific methylation analysis, CRISPR/Cas9-mediated genome editing, and RT-qPCR (quantitative RT-PCR) and immunoblot assays, we found that short-term treatment (a few hours) with the proinflammatory cytokine tumor necrosis factor α (TNFα) activates IL-32 in a DNA demethylation-independent manner. In contrast, prolonged TNFα treatment (several days) induced DNA demethylation at the promoter and a CpG island in the IL-32 gene in a TET (ten-eleven translocation) family enzyme- and NF-κB-dependent manner. Notably, the hypomethylation status of transcriptional regulatory elements in IL-32 was maintained for a long time (several weeks), causing elevated IL-32 expression even in the absence of TNFα. Considering that IL-32 can, in turn, induce TNFα expression, we speculate that such feedforward events may contribute to the transition from an acute inflammatory response to chronic inflammation.

Synthesis and Evaluation of a New Type of Small Molecule Epigenetic Modulator Containing Imidazo[1,2-b][1,2,4]triazole Motif

Epigenetic modifications such as DNA methylation is important for many cellular processes, such as cell differentiation and cell death. The disorder of epigenetic state is closely related to human diseases, especially cancers. DNA methylation is a well-characterized epigenetic modification which is related to gene silencing and is considered as a repressive epigenetic mark. DNA methylation caused gene repression can be derepressed by chemical agents. Small molecules targeting DNA methyltransferases, histone deacetylases, and other regulatory factors can activate genes silenced by DNA methylation. However, more and more studies have shown that histone deacetylation is not the only downstream event of DNA methylation. Some additional, unknown mechanisms that promote DNA methylation-mediated gene silencing may exist. Recently, through high-throughput screening using a 308,251-member chemical library to identify potent small molecules that derepress an EGFP reporter gene silenced by DNA methylation, we identified seven hit compounds that did not directly target bulk DNA methylation or histone acetylation. Three of them (LX-3, LX-4, LX-5) were proven to selectively activate the p38 MAPK pathway in multiple cell types. In order to identify the exact cellular targets of these compounds, we turn to work on the SAR study of LX-3 by constructing a structurally diverse chemical library based on the imidazo[1,2-b][1,2,4]triazole core structure via diversity-oriented synthesis. Our work provides a general approach to efficiently access diverse heterocyclic molecules with interesting epigenetic modulation activities.

CSE1L participates in regulating cell mitosis in human seminoma

Objectives

CSE1L has been reported to be highly expressed in various tumours. Testicular germ cell tumours are common among young males, and seminoma is the major type. However, whether CSE1L has functions in the seminoma is unclear.

Materials and methods

The expression of CSE1L was detected by immunohistochemistry in seminoma tissues and non‐tumour normal testis tissues from patients. CSE1L distribution during cell mitosis was determined by immunofluorescent staining with CSE1L, α‐tubulin and γ‐tubulin antibodies. The effects of Cse1L knockdown on cell proliferation and cell cycle progression were determined by Cell Counting Kit‐8 assay, flow cytometry, PH3 staining and bromodeoxyuridine incorporation assay.

Results

CSE1L was significantly enriched in the seminoma tissue compared with the non‐tumour normal testis tissue. CSE1L also co‐localized with α‐tubulin in the cells with a potential to divide. In the seminoma cell line TCam‐2, CSE1L was associated with the spindles and the centrosomes during cell division. The knockdown of CSE1L in TCam‐2 cells attenuated the cells’ proliferative capacity. Cell cycle assay revealed that the CSE1L‐deficient cells were mainly arrested in the G0/G1 phase and moderately delayed in the G2/M phase. The proportion of cells with multipolar spindle and abnormal spindle geometry was obviously increased by CSE1L expression silencing in the TCam‐2 cells.

Conclusions

Overall, these findings showed that CSE1L plays a pivotal role in maintaining cell proliferation and cell division in seminomas.

Epigenetic Changes in the Regulation of Nicotiana tabacum Response to Cucumber Mosaic Virus Infection and Symptom Recovery through Single-Base Resolution Methylomes

Plants have evolved multiple mechanisms to respond to viral infection. These responses have been studied in detail at the level of host immune response and antiviral RNA silencing (RNAi). However, the possibility of epigenetic reprogramming has not been thoroughly investigated. Here, we identified the role of DNA methylation during viral infection and performed reduced representation bisulfite sequencing (RRBS) on tissues of Cucumber mosaic virus (CMV)-infected Nicotiana tabacum at various developmental stages. Differential methylated regions are enriched with CHH sequence contexts, 80% of which are located on the gene body to regulate gene expression in a temporal style. The methylated genes depressed by methyltransferase inhibition largely overlapped with methylated genes in response to viral invasion. Activation in the argonaute protein and depression in methyl donor synthase revealed the important role of dynamic methylation changes in modulating viral clearance and resistance signaling. Methylation-expression relationships were found to be required for the immune response and cellular components are necessary for the proper defense response to infection and symptom recovery.