Cell division cyclin 25C knockdown inhibits hepatocellular carcinoma development by inducing endoplasmic reticulum stress

BACKGROUND Cell division cyclin 25C(CDC25C)is a protein that plays a critical role in the cell cycle,specifically in the transition from the G2 phase to the M phase.Recent research has shown that CDC25C could be a potential therapeutic target for cancers,particularly for hepatocellular carcinoma(HCC).However,the specific regulatory mechanisms underlying the role of CDC25C in HCC tumorigenesis and development remain incompletely understood.AIM To explore the impact of CDC25C on cell proliferation and apoptosis,as well as its regulatory mechanisms in HCC development.METHODS Hepa1-6 and B16 cells were transduced with a lentiviral vector containing shRNA interference sequences(LV-CDC25C shRNA)to knock down CDC25C.Subsequently,a xenograft mouse model was established by subcutaneously injecting transduced Hepa1-6 cells into C57BL/6 mice to assess the effects of CDC25C knockdown on HCC development in vivo.Cell proliferation and migration were evaluated using a Cell Counting Kit-8 cell proliferation assays and wound healing assays,respectively.The expression of endoplasmic reticulum(ER)stress-related molecules(glucose-regulated protein 78,X-box binding protein-1,and C/EBP homologous protein)was measured in both cells and subcutaneous xenografts using quantitative real-time PCR(qRT-PCR)and western blotting.Additionally,apoptosis was investigated using flow cytometry,qRT-PCR,and western blotting.RESULTS CDC25C was stably suppressed in Hepa1-6 and B16 cells through LV-CDC25C shRNA transduction.A xenograft model with CDC25C knockdown was successfully established and that downregulation of CDC25C expression significantly inhibited HCC growth in mice.CDC25C knockdown not only inhibited cell proliferation and migration but also significantly increased the ER stress response,ultimately promoting ER stress-induced apoptosis in HCC cells.CONCLUSION The regulatory mechanism of CDC25C in HCC development may involve the activation of ER stress and the ER stress-induced apoptosis signaling pathway.

Discovery of a potent and selective cell division cycle 7 inhibitor from 6-(3-fluoropyridin4-yl)thieno[3,2-d]pyrimidin-4(3H)-one derivatives as an orally active antitumor agent

To the Editor:Kinase cell division cycle 7(CDC7),a cell division cycle protein,takes a vital role in mediating DNA replication1.CDC7 complexes in the nucleus can phosphorylate the minichromosome maintenance complex(MCM)family members that bind to chromosomes.In addition,CDC7 kinase,as a molecular switch regulating DNA replication,can mediate DNA damage signaling pathways to stimulate cell cycle termination as well as DNA replication2.Studies have shown that CDC7 is overexpressed in many types of cancer cells,and its overexpression was related to poor patient survival,tumor grade,genetic instability,aneuploidy and so on3.Therefore,CDC7 is a promising target for antitumor therapy.

Asymmetric cell division in plant development

Asymmetric cell division(ACD) is a fundamental process that generates new cell types during development in eukaryotic species.In plant development,post-embryonic organogenesis driven by ACD is universal and more important than in animals,in which organ pattern is preset during embryogenesis.Thus,plant development provides a powerful system to study molecular mechanisms underlying ACD.During the past decade,tremendous progress has been made in our understanding of the key components and mechanisms involved in this important process in plants.Here,we present an overview of how ACD is determined and regulated in multiple biological processes in plant development and compare their conservation and specificity among different model cell systems.We also summarize the molecular roles and mechanisms of the phytohormones in the regulation of plant ACD.Finally,we conclude with the overarching paradigms and principles that govern plant ACD and consider how new technologies can be exploited to fill the knowledge gaps and make new advances in the field.

PatU3 plays a central role in coordinating cell division and differentiation in pattern formation of filamentous cyanobacterium Nostoc sp.PCC 7120

Spatial periodic signal for cell differentiation in some multicellular organisms is generated according to Turing's principle for pattern formation.How a dividing cell responds to the signal of differentiation is addressed with the filamentous cyanobacterium Nostoc sp.PCC 7120,which forms the patterned distribution of heterocysts.We show that differentiation of a dividing cell was delayed until its division was completed and only one daughter cell became heterocyst.A mutant of patU3,which encodes an inhibitor of heterocyst formation,showed no such delay and formed heterocyst pairs from the daughter cells of cell division or dumbbell-shaped heterocysts from the cells undergoing cytokinesis.The patA mutant,which forms heterocysts only at the filament ends,restored intercalary heterocysts by a single nucleotide mutation of patU3,and double mutants of patU3/patA and patU3/hetF had the phenotypes of the patU3 mutant.We provide evidence that HetF,which can degrade PatU3,is recruited to cell divisome through its C-terminal domain.A HetF mutant with its N-terminal peptidase domain but lacking the C-terminal domain could not prevent the formation of heterocyst pairs,suggesting that the divisome recruitment of HetF is needed to sequester HetF for the delay of differentiation in dividing cells.Our study demonstrates that PatU3 plays a key role in celldivision coupled control of differentiation.

Salicylic acid promotes quiescent center cell division through ROS accumulation and down-regulation of PLT1,PLT2,and WOX5

Salicylic acid(SA)plays a crucial role in plant immunity.However,its function in plant development is poorly understood.The quiescent center(QC),which maintains columella stem cells(CSCs)in the root apical meristem and typically exhibits low levels of cell division,is critical for root growth and development.Here,we show that the Arabidopsis thaliana SA overaccumulation mutant constitutively activated cell death 1(cad1),which exhibits increased cell division in the QC,is rescued by additional mutations in genes encoding the SA biosynthetic enzyme SALICYLIC ACID INDUCTION DEFFICIENT2(SID2)or the SA receptor NONEXPRESSER OF PR GENES1(NPR1),indicating that QC cell division in the cad1 mutant is promoted by the NPR1-dependent SA signaling pathway.The application of exogenous SA also promoted QC cell division in wild-type plants in a dose-dependent manner and largely suppressed the expression of genes involved in QC maintenance,including those encoding the APETALA2(AP2)transcription factors PLETHORA1(PLT1)and PLT2,as well as the homeodomain transcription factor WUSCHEL-RELATED HOMEOBOX5(WOX5).Moreover,we showed that SA promotes reactive oxygen species(ROS)production,which is necessary for the QC cell division phenotype in the cad1 mutant.These results provide insight into the function of SA in QC maintenance.

Poly(ADP-ribose) polymerases regulate cell division and development in Arabidopsis roots

Root organogenesis involves cell division, differentiation and expansion. The molecular mechanisms regulating root development are not fully understood. In this study, we identified poly（adenosine diphosphate （ADP）-ribose） polymerases （PARPs） as new players in root development. PARP catalyzes poly（ADP-ribosyl）ation of proteins by repeatedly adding ADP-ribose units onto proteins using nicotinamide adenine dinucleotide （NAD ） as the donor. We found that inhibition of PARP activities by 3-aminobenzomide （3-AB） increased the growth rates of both primary and lateral roots, leading to a more developed root system. The double mutant of Arabidopsis PARPs, parplparp2, showed more rapid primary and lateral root growth. Cyclin genes regulating G1-to-S and G2-to-M transition were up-regulated upon treatment by 3-AB. The proportion of 2C ceils increased while cells with higher DNA ploidy declined in the roots of treated plants, resulting in an enlarged root meristematic zone. The expression level of PARP2 was very low in the meristematic zone but high in the maturation zone, consistent with a role of PARP in inhibiting mitosis and promoting cell differentiation. Our results suggest that PARPs play an important role in root development by negatively regulating root cell division.

Overexpression of OsKTN80a, a katanin P80ortholog, caused the repressed cell elongation and stalled cell division mediated by microtubule apparatus defects in primary root in Oryza sativa

Katanin, a microtubule-severing enzyme, consists of two subunits：the catalytic subunit P60, and the regulatory subunit P80. In several species, P80 functions in meiotic spindle organization, the flagella biogenesis, the neuronal development, and the male gamete production. However, the P80 function in higher plants remains elusive. In this study, we found that there are three katanin P80 orthologs （OsKTN80a, OsKTN80b, and OsKTN80c） in Oryza sativa L. Overexpression of OsKTN80a caused the retarded root growth of rice seedlings. Further investigation indicates that the retained root growth was caused by the repressed cell elongation in the elongation zone and the stalled cytokinesis in the division zone in the root tip. The in vivo examination suggests that OsKTN80a acts as a microtubule stabilizer. We＆amp;nbsp;prove that OsKTN80a, possibly associated with OsKTN60, is involved in root growth via regulating the cell elongation and division.

Three Dimensional Simulation Method in Early Process of Division and Growth for Tumour Cells

The process of division, growth and death for tumour cell mass in the early is simulated. An integrated GUI is provided for users to set the value of each parameters, which are cell growth rates, cell mass division rates, cell mass death rates, simulate type, maximum running time, polarity and cell colour. It can display the growth process of each cell on result GUI. Also, it can display the values of each parameters for observing and analysing in current life cycle on result GUI, which are cell mass division times, cell mass death rate, cell mass division rate and cell mass growth rate. In the process of simulation, The cell growth rate is described by the approach to combine the exponential model with the linear model. In addition, a linked list data structure to store the tumour cells is used by the cellular automata for a reference to determine the position of each cell. It sets up two linked list to store the cells, one of them save the new small division cells and the other one save the big cell. That can make the painting process of cells on result GUI clearer and more organized. At last, the polarity oftumour growth is described for determining the growth direction of cells.

Gluconate 5-dehydrogenase （Ga5DH） participates in Streptococcus suis cell division

Bacterial cell division is strictly regulated in the formation of equal daughter cells. This process is governed by a series of spatial and temporal regulators, and several new factors of interest to the field have recently been identified. Here, we report the requirement of gluconate 5-dehydrogenase （Ga5DH） in cell division of the zoonotic pathogen Strepto- coccus suis. GaSDH catalyzes the reversible reduction of 5-ketogluconate to D-gluconate and was localized to the site of cell division. The deletion of Ga5DH in S. suis resulted in a plump morphology with aberrant septa joining the progeny. A significant increase was also observed in cell length. These defects were determined to be the conse- quence of Ga5DH deprivation in S. suis causing FtsZ delo- calization. In addition, the interaction of FtsZ with Ga5DH in vitro was confirmed by protein interaction assays. These results indicate that GaSDH may function to prevent the formation of ectopic Z rings during S. suis cell division.

Expression of CDC42 in cervical squamous cell carcinoma and its correlation with clinicopathologic characteristics

Objective： The high expression of cell division cycle 42 protein （CDC42） may be involved in the occurrence and progression of several tumors. However, the expression and function of CDC42 in cervical squamous cell carcinoma remains unclear. This study aimed to investigate the expression of CDC42 in cervical squamous cell carcinoma and its correlation with clinicopathologic characteristics. Methods： The expression of CDC42 in 162 cervical squamous cell carcinoma tissue samples and 33 normal cervical tissue samples was investigated by immunohistochemistry. The CDC42 mRNA expression was detected by reverse transcription-polymerase chain reaction （RT-PCR）. Results： The cervical squamous cell carcinoma group showed a significantly higher CDC42 positive rate, compared to the normal cervical tissues （P〈0.05）. Fttrthermore, the tissues of stage Ⅱ-Ⅳ carcinoma patients showed higher CDC42 expression levels compared to stage I patients （P=0.05）. In addition, the expression of CDC42 was not correlated to age of patients, differentiation degree of cancer cells, or lymph node metastasis （P〉0.05）. Furthermore, compare with normal cervical tissues, the CDC42 mRNA expression in cervical cancer had no significant difference. Conclusions： CDC42 was up-regulated at protein level, but not mRNA level, in cervical squamous cell carcinoma. The high expression of CDC42 was correlated to the clinical stage of the patients, indicating that CDC42 might contribute to the progression of cervical squamous cell carcinoma.

Cell proliferation during hair cell regeneration induced by Math1 in vestibular epithelia in vitro

Hair cell regeneration is the fundamental method of correcting hearing loss and balance disorders caused by hair cell damage or loss. How to promote hair cell regeneration is a hot focus in current research. In mammals, cochlear hair cells cannot be regenerated and few vestibular hair cells can be renewed through spontaneous regeneration. However, Math1 gene transfer allows a few inner ear cells to be transformed into hair cells in vitro or in vivo. Hair cells can be renewed through two possible means in birds： supporting cell differentiation and transdifferentiation with or without cell division. Hair cell regeneration is strongly associated with cell proliferation. Therefore, this study explored the relationship between Math1-induced vestibular hair cell regeneration and cell division in mammals. The mouse vestibule was isolated to harvest vestibular epithelial cells. Ad-Math1-enhanced green fluorescent protein （EGFP） was used to track cell division during hair cell transformation.5-Bromo-2′-deoxyuridine （BrdU） was added to track cell proliferation at various time points. Immunocytochemistry was utilized to determine cell differentiation and proliferation. Results demonstrated that when epithelial cells were in a higher proliferative stage, more of these cells differentiated into hair cells by Math1 gene transfer. However, in the low proliferation stage, no BrdU-positive cells were seen after Math1 gene transfer. Cell division always occurred before Math1 transfection but not during or after Math1 transfection, when cells were labeled with BrdU before and after Ad-Math1-EGFP transfection. These results confirm that vestibular epithelial cells with high proliferative potential can differentiate into new hair cells by Math1 gene transfer, but this process is independent of cell proliferation.

Anti-hepatoma Effect of DC2.4 Cells Transfected with Tumor-Associated Antigen Cdc25C In Vitro

Objective Cell division cyclin 25 homolog C(Cdc25C)is a tumor-associated antigen candidate gene,and this may be used as an effective target in cancer treatment.The present study aims to evaluate the lysis effect of cytotoxic T lymphocytes(CTLs)induced by dendritic cell line DC2.4 overexpressing Cdc25C,and the feasibility of Cdc25C as a component in hepatoma immunotherapy.Methods The mouse Cdc25C gene was ligated into a lentiviral vector,and transfected into DC2.4 cells.The DC2.4 cell phenotype and cytokine secretion were determined by flow cytometry and ELISA,respectively.CD8^(+)T cells were sorted from the spleens of C57BL/6 mice using a magnetic bead sorting kit obtained from Miltenyi Biotech,Germany,and co-cultured with DC2.4 cells for one week as effector cells.Then,IL-2,granzyme B and perforin were detected in the CTL culture medium by ELISA.Next,time-resolved fluorescence immunoassay was used to detect the immune killing effect of Cdc25C-specific CTLs on target cells.Meanwhile,the effect of blocking MHC-I sites on target cells with a monoclonal anti-MHC-I antibody was evaluated.Results The results revealed that Cdc25C could be stably overexpressed in DC2.4 cells by LV-Cdc25C infection.DC2.4 cells transfected with LV-Cdc25C secreted more IL-6,IL-12,TNF-αand IFN-γ,and had higher expression levels of CD40,CD86,CCR7 and MHC-II than unaltered DC2.4 cells.The elevated Cdc25C in dendritic cells also further increased the secretion of IL-2,granzyme B and perforin to elicit Cdc25C-specific CTLs,and induced the higher cytotoxicity in Hepa1-6 cell lines(P<0.05),but this had no effect on the target cells when MHC-I monoclonal antibodies were blocked.Conclusion DC2.4 cells transfected with LV-Cdc25C can induce specific CTLs,and result in a strong cellular immune response.The dendritic cells that overexpress Cdc25C may be useful for hepatoma immunotherapy.

How does FtsZ’s treadmilling help bacterial cells divide?

Most bacteria assemble a ring-like macromolecular machinery scaffolded by the essential cytoskeletal protein FtsZ for cell division.Studies have broadly explored how FtsZ could polymerize at the correct place and time.Recently,the FtsZ-ring was found to exhibit dynamic treadmilling along the circumference of the division site,driven by GTP hydrolysis.This apparently directional motion of FtsZ seems to drive the movement of septal cell wall synthesis enzymes and to play an important role in modulating cell envelope constriction and septum morphogenesis.However,the relationship between FtsZ’s treadmilling dynamics and cell wall synthesis varies in different bacteria.More importantly,the biophysical and molecular mechanisms governing these dynamic processes are unclear.In this viewpoint,we will focus on some new and exciting studies surrounding this topic and discuss potential mechanisms that underlie how FtsZ’s treadmilling dynamics might regulate septal cell wall synthesis and cell division.

Automated Dynamic Cellular Analysis in Time-Lapse Microscopy

Analysis of cellular behavior is significant for studying cell cycle and detecting anti-cancer drugs. It is a very difficult task for image processing to isolate individual cells in confocal microscopic images of non-stained live cell cultures. Because these images do not have adequate textural variations. Manual cell segmentation requires massive labor and is a time consuming process. This paper describes an automated cell segmentation method for localizing the cells of Chinese hamster ovary cell culture. Several kinds of high-dimensional feature descriptors, K-means clustering method and Chan-Vese model-based level set are used to extract the cellular regions. The region extracted are used to classify phases in cell cycle. The segmentation results were experimentally assessed. As a result, the proposed method proved to be significant for cell isolation. In the evaluation experiments, we constructed a database of Chinese Hamster Ovary Cell’s microscopic images which includes various photographing environments under the guidance of a biologist.

硼扩散设备温度控制系统的研究与实现

近年来,随着光伏行业持续快速的发展,n型TOPCon太阳电池技术路线得到市场认可,产能不断扩张。硼扩散设备作为TOPCon太阳电池核心工艺设备之一受到市场极大的关注,其温度控制系统在工艺生产过程起着决定性的作用。对比硼扩散设备实际应用过程中传统炉体使用水平插片方式和顺气流垂直插片方式后得到的硅片片间的方阻均匀性,发现水平插片方式存在舟内中层硅片方阻偏高,方阻均匀性不满足技术性指标要求的问题。对此设计了新型分区炉体,提出3种温度控制系统方案,并通过工艺验证得出满足技术性指标要求的方案。研究结果表明:分区炉体搭配水平插片方式时,采用温度控制系统方案3可以满足技术性指标的要求。

TATA-box binding protein-associated factor 2 regulates grain size in rice

Grain size,characterized by a combination of grain length,width,and thickness,is one of the major determinants of yield in rice.The present study identified TATA-box binding protein-associated factor 2(TAF2)as an essential component regulating transcription and determining grain size in rice.Map-based cloning showed that a G/T substitution in TAF2 resulted in a naturally occurring mutant called reduced grain size and plant height 1(rgh1).The mutants,with weak edited rgh1 alleles,exhibited a small grain phenotype with reduced grain length and width,while the severe knockout mutant(rgh1-2s)was dwarf and completely sterile.Allelic test performed between rgh1 and several edited alleles confirmed that the mutation in TAF2 caused the rgh1 phenotype.GUS staining showed that TAF2 was mainly expressed in the vascular bundles of roots,stems,leaves,and grains.The cytological analysis revealed that reduced cell division in the glumes resulted in the small grain phenotype of rgh1.Further RNA-sequencing detected altered expression of genes involved in the basic biological processes in rgh1 mutant.These findings provide novel insights into the TAF2-mediated genetic mechanism regulating grain size in rice.

Mechanisms simultaneously regulate smooth muscle proliferation and differentiation

Vascular smooth muscle cell （VSMC） differentiation and proliferation are two important physiological proc- esses during vascular development. The phenotypic alteration from differentiated to proliferative VSMC contrib- utes to the development of several major cardiovascular diseases including atherosclerosis, hypertension, resteno- sis after angioplasty or bypass, diabetic vascular complications, and transplantation arteriopathy. Since the VSMC phenotype in these pathological conditions resembles that of developing VSMC during embryonic development, understanding of the molecular mechanisms that control VSMC differentiation will provide fundamental insights into the pathological processes of these cardiovascular diseases. Although VSMC differentiation is usually ac- companied by an irreversible cell cycle exit, VSMC proliferation and differentiation occur concurrently during embryonic development. The molecular mechanisms simultaneously regulating these two processes, however, remain largely unknown. Our recent study demonstrates that cell division cycle 7, a key regulator of cell cycle, promotes both VSMC differentiation and proliferation through different mechanisms during the initial phase of VSMC differentiation. Conversely, Kriappel-like factor 4 appears to be a repressor for both VSMC differentia- tion and proliferation. This review attempts to highlight the novel role of cell division cycle 7 in TGF-β-induced VSMC differentiation and proliferation. The role of K141ppel-like factor 4 in suppressing these two processes will also be discussed.

A new loss-of-function allele 28y reveals a role of ARGONAUTE1 in limiting asymmetric division of stomatal lineage ground cell

In Arabidopsis thaliana L., stomata are produced through a series of divisions including asymmetric and symmetric divisions. Asymmetric entry division of meristemoid mother cellproduces two daughter cells, the smal er meristemoid and the larger sister cell, a stomatal lineage ground cell（SLGC）. Stomatal lineage ground cells can differentiate into epidermal pavement cells but have the potential to divide asymmetrical y, spacing divisions, to create satel ite meristemoids. Peptide ligands and TOO MANY MOUTHS （TMM） and ERECTA family receptors regulate the initiation of stomatal lineages, activity, and orientation of spacing divisions. Here, we reported that a natural mutant 28y displayed an increased stomatal density and index. Using map-based cloning, we identified mutation in ARGONAUTE1 （AGO1） as the cause of 28y phenotypes. Time-lapse tracing of stomatal lineage cells reveals that stomatal overproduction in 28y is caused by the excessive asymmetric spacing division of SLGCs.Further genetic results demonstrated that AGO1 acts down-stream of TMM and negatively regulates the SPCH transcripts, but in a brassinosteroid-independent manner. Upregulation of AGAMOUS-LIKE16 （AGL16） in 28y mutants suggests that AGO1 is required to restrict AGL16-mediated stomatal spacing divisions, an miRNA pathway in addition to ligand-receptor signaling modules.

灵芪胶囊含药血清对人红白血病K562细胞增殖抑制作用的影响

目的:观察灵芪胶囊(LQC)含药血清在体外对K562白血病细胞增殖抑制作用的影响。方法:采用血清药理学方法制备灵芪胶囊含药血清,以不同浓度的含药血清处理体外培养的K562白血病细胞,并测定抑制率、分裂指数以及克隆形成能力,观察灵芪胶囊含药血清对肿瘤细胞的抑制作用;用W right-G iemsa染色方法观察肿瘤细胞形态的变化。结果:不同浓度灵芪胶囊含药血清对K562细胞的增殖具有抑制作用,并呈剂量依赖关系;灵芪胶囊含药血清对肿瘤细胞的分裂指数和克隆形成能力均具有显著的降低作用,在一定的时间内与剂量呈正相关,同时亦使肿瘤细胞的形态结构发生改变。结论:灵芪胶囊含药血清对K562白血病细胞具有细胞毒作用,其直接杀伤和破坏肿瘤细胞的作用是灵芪胶囊抗肿瘤的主要机理之一。

Cloning,localization and expression analysis of two fw2.2-like genes in small-and large-fruited pear species

Fruit size is one of the most important agronomic characters,which is mainly determined by cell number and cell size.However,our current knowledge about pear is largely unknown.Through counting of pear mesocarp cells at different stages,we found that the cell number,rather than the cell size,is responsible for the differences between small- and large-fruited cultivars.Fruit weight-2.2（fw2.2） is an important quantitative trait locus（QTL） affecting fruit weight in tomato and functions as a negative regulator in carpel cell division.To get more insights into this QTL in pear fruit development,we isolated two putative homologous fw2.2 genes,which were designated as fw2.2-like（PbFWL） genes.PbFWLs encode Cys-rich proteins with the CCXXXXCPC motif and belong to the PLAC8 superfamily.In addition,results from the subcellular localization indicated that PbFWLs were localized in the plasma membrane.The expression profile of the PbFWL genes by qRT-PCR showed they expressed higher in small-sized fruit cultivar than that in large-sized fruit cultivar during the cell division period.In summary,our data suggest that these two PbFWLs might be negatively related to the cell division in pear fruit.