LG-ESSs and HG-ESSs: underlying molecular alterations and potential therapeutic strategies

Endometrial stromal tumors(ESTs) include endometrial stromal nodule(ESN), low-grade endometrial stromal sarcoma(LG-ESS), high-grade endometrial stromal sarcoma(HG-ESS), and undifferentiated uterine sarcoma(UUS). Since these are rare tumor types, there is an unmet clinical need for the systematic therapy of advanced LG-ESS or HG-ESS. Cytogenetic and molecular advances in ESTs have shown that multiple recurrent gene fusions are present in a large proportion of LG-ESSs, and HG-ESSs are identified by the tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein epsilon(YWHAE)-family with sequence similarity 22(FAM22) fusion. Recently, a group of ESSs harboring both zinc finger CCCH domain-containing protein7 B(ZC3H7B)-B-cell lymphoma 6 corepressor(BCOR) fusion and internal tandem duplication(ITD) of the BCOR gene have been provisionally classified as HG-ESSs. In this review, we firstly describe current knowledge about the molecular characteristics of recurrent aberrant proteins and their roles in the tumorigenesis of LG-ESSs and HG-ESSs. Next, we summarize the possibly shared signal pathways in the tumorigenesis of LG-ESSs and HG-ESSs, and list potentially actionable targets. Finally, based on the above discussion, we propose a few promising therapeutic strategies for LG-ESSs and HG-ESSs with recurrent gene alterations.     

DNA-damage response network at the crossroads of cell-cycle checkpoints,cellular senescence and apoptosis

Tissue homeostasis requires a carefully-orchestrated balance between cell proliferation, cellular senescence and cell death. Cells proliferate through a cell cycle that is tightly regulated by cyclin-dependent kinase activities. Cellular senescence is a safeguard program limiting the proliferative competence of cells in living organisms. Apoptosis eliminates unwanted cells by the coordinated activity of gene products that regulate and effect cell death. The intimate link between the cell cycle, cellular senescence, apoptosis regulation, cancer development and tumor responses to cancer treatment has become eminently apparent. Extensive research on tumor suppressor genes, oncogenes, the cell cycle and apoptosis regulatory genes has revealed how the DNA damage-sensing and -signaling pathways, referred to as the DNA-damage response network, are tied to cell proliferation, cell-cycle arrest, cellular senescence and apoptosis. DNA-damage responses are complex, involving ＂sensor＂ proteins that sense the damage, and transmit signals to ＂transducer＂ proteins, which, in turn, convey the signals to numerous ＂effector＂ proteins implicated in specific cellular pathways, including DNA repair mechanisms, cell-cycle checkpoints, cellular senescence and apoptosis. The Bcl-2 family of proteins stands among ＂the mos＂t crucial regula＂tors of apop＂tosis and performs vi＂tal func＂tions in deciding whether a cell will live or die after cancer chemotherapy and irradiation. In addition, several studies have now revealed that members of the Bcl-2 family also interface with the cell cycle, DNA repair/recombination and cellular senescence, effects that are generally distinct from their function in apoptosis. In this review, we report progress in understanding the molecular networks that regulate cell-cycle checkpoints, cellular senescence and apoptosis after DNA damage, and discuss the influence of some Bcl-2 family members on cell-cycle checkpoint regulation.     

尿路上皮癌p53bax基因蛋白的表达及意义

目的:为了探讨细胞凋亡促进基因bax在尿路上皮癌中染色的表达及意义以及与p53蛋白表达的相互关系。方法:对65例尿路上皮癌石蜡标本进行免疫组化。结果:bax蛋白阳性率为50.77％,且与肿瘤病理分级有关,其阳性细胞主要分布于高分化癌及浅表性癌。分级间比较有显著性差异(P<0.05)。分期间比较差异无显著性。p53蛋白阳性率为46.15％,与bax相反,在低分化及浸润性癌组织阳性率明显高于高分化及浅表性癌(P<0.05)。结论:作为细胞凋亡促进基因bax丢失与p53基因突变一样与尿路上皮癌的发生发展有关。检测bax与D53基因蛋白可进一步了解尿路上皮癌生物学信息,也为临床提供更有价值的预后判断指标。     

A serpentine way to signaling

The Nobel Prize in Chemistry, 2012 has been awarded to Robert J Lefkowitz and Brian K Kobilka for their studies on G-Protein Coupled Receptors (GPCRs). GPCRs are receptor proteins present on the cell surface, which are involved in sensing molecules outside the cell and initiating a cellular response. They can sense a wide variety of ligands ranging from light to hormones and small peptides, triggering various physiological responses. Today we understand the molecular mechanisms by which these receptors work largely due to the contributions of Lefkowitz and Kobilka. Owing to the role of GPCRs in cell communication and involvement in various disease conditions, they are targets of over 40% of current drugs in the market. These findings have not only revealed how GPCRs work, but have also made a huge impact on the field of GPCR-associated drug discovery.     

Regulation of cellular and molecular functions by protein phosphorylation

Modification of proteins by phosphorylation is the major general mechanism by which many cellular functions in eukaryotic cells such as cell division, malignant transformation, differentiation, signal transduction etc. are controlled by external physiological stimuli. At the molecular level protein phosphorylation-dephosphorylation can alter various properties of the substrate molecules such as enzymatic activity, sub-Cellular location, ligand binding, interaction with other proteins, DNA binding and some other functional properties. The changes in molecular properties of proteins brought about by protein phosphorylation play a critical role in regulating various cellular functions.     

Impairment of liver regeneration by the histone deacetylase inhibitor valproic acid in mice

Background and objective: Liver regeneration is a complex process regulated by a group of genetic and epigenetic factors. A variety of genetic factors have been reported, whereas few investigations have focused on epigenetic regulation during liver regeneration. In the present study, valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, was used to investigate the effect of HDAC on liver regeneration. Methods: VPA was administered via intraperitoneal injection to 2/3 partially hepatectomized mice to detect hepatocyte proliferation during liver regeneration. The mice were sacrificed, and their liver tissues were harvested at sequential time points from 0 to 168 h after treatment. DNA synthesis was detected via a BrdU assay, and cell proliferation was tested using Ki-67. The expressions of cyclin D1, cyclin E, cyclin dependent kinase 2 (CDK2), and CDK4 were detected by Western blot analysis. Chromatin immunoprecipitation (ChIP) assay was used to examine the recruitment of HDACs to the target promoter regions and the expression of the target gene was detected by Western blot. Results: Immunohistochemical analysis showed that cells positive for BrdU and Ki-67 decreased, and the peak of BrdU was delayed in the VPA-administered mice. Consistently, cyclin D1 expression was also delayed. We identified B-myc as a target gene of HDACs by complementary DNA (cDNA) microarray. The expression of B-myc increased in the VPA-administered mice after hepatectomy (PH). The ChIP assay confirmed the presence of HDACs at the B-myc promoter. Conclusions: HDAC activities are essential for liver regeneration. Inhibiting HDAC activities delays liver regeneration and induces liver cell cycle arrest, thereby causing an anti-proliferative effect on liver regeneration.     

Using Affinity Chromatography to Investigate Novel Protein–Protein Interactions in an Undergraduate Cell and Molecular Biology Lab Course

Inquiry-driven lab exercises require students to think carefully about a question, carry out an investigation of that question, and critically analyze the results of their investigation. Here, we describe the implementation and assessment of an inquiry-based laboratory exercise in which students obtain and analyze novel data that contribute to our understanding of macromolecular trafficking between the nucleus and cytoplasm in eukaryotic cells. Although many of the proteins involved in nucleocytoplasmic transport are known, the physical interactions between some of these polypeptides remain uncharacterized. In this cell and molecular biology lab exercise, students investigate novel protein–protein interactions between factors involved in nuclear RNA export. Using recombinant protein expression, protein extraction, affinity chromatography, SDS-polyacrylamide gel electrophoresis, and Western blotting, undergraduates in a sophomore-level lab course identified a previously unreported association between the soluble mRNA transport factor Mex67 and the C-terminal region of the yeast nuclear pore complex protein Nup1. This exercise immersed students in the process of investigative science, from proposing and performing experiments through analyzing data and reporting outcomes. On completion of this investigative lab sequence, students reported enhanced understanding of the scientific process, increased proficiency with cellular and molecular methods and content, greater understanding of data analysis and the importance of appropriate controls, an enhanced ability to communicate science effectively, and an increased enthusiasm for scientific research and for the lab component of the course. The modular nature of this exercise and its focus on asking novel questions about protein–protein interactions make it easily transferable to undergraduate lab courses performed in a wide variety of contexts.     

Kinesin KIF4A is associated with chemotherapeutic drug resistance by regulating intracellular trafficking of lung resistance-related protein

Multidrug resistance (MDR) is the major impediment to cancer chemotherapy. The expression of lung resistance-related protein (LRP), a non-ATP-binding cassette (ABC) transporter, is high in tumor cells, resulting in their resistance to a variety of cytotoxic drugs. However, the function of LRP in tumor drug resistance is not yet explicit. Our previous studies had shown that Kinesin KIF4A was overexpressed in cisplatin (DDP)-resistant human lung adenocarcinoma cells (A549/DDP cells) compared with A549 cells. The expression of KIF4A in A549 or A549/DDP cells significantly affects cisplatin resistance but the detailed mechanisms remain unclear. Here, we performed co-immunoprecipitation experiments to show that the tail domain of KIF4A interacted with the N-terminal of LRP. Immunofluorescence images showed that both the ability of binding to LRP and the motility of KIF4A were essential for the dispersed cytoplasm distribution of LRP. Altogether, our results shed light on a potential mechanism in that motor protein KIF4A promotes drug resistance of lung adenocarcinoma cells through transporting LRP-based vaults along microtubules towards the cell membrane. Thus KIF4A might be a cisplatin resistance-associated protein and serves as a potential target for chemotherapeutic drug resistance in lung cancer.     

Epstein-Barr virus interactions with the Bcl-2 protein family and apoptosis in human tumor cells

Epstein-Barr virus(EBV),a human gammaherpesvirus carried by more than 90% of the world’s population,is associated with malignant tumors such as Burkitt’s lymphoma(BL),Hodgkin lymphoma,post-transplant lymphoma,extra-nodal natural killer/T cell lymphoma,and nasopharyngeal and gastric carcinomas in immune-compromised patients.In the process of infection,EBV faces challenges:the host cell environment is harsh,and the survival and apoptosis of host cells are precisely regulated.Only when host cells receive sufficient survival signals may they immortalize.To establish efficiently a lytic or long-term latent infection,EBV must escape the host cell immunologic mechanism and resist host cell apoptosis by interfering with multiple signaling pathways.This review details the apoptotic pathway disrupted by EBV in EBV-infected cells and describes the interactions of EBV gene products with host cellular factors as well as the function of these factors,which decide the fate of the host cell.The relationships between other EBV-encoded genes and proteins of the B-cell leukemia/lymphoma(Bcl) family are unknown.Still,EBV seems to contribute to establishing its own latency and the formation of tumors by modifying events that impact cell survival and proliferation as well as the immune response of the infected host.We discuss potential therapeutic drugs to provide a foundation for further studies of tumor pathogenesis aimed at exploiting novel therapeutic strategies for EBV-associated diseases.     

乳腺癌组织中c-erbB-2、p53和nm23蛋白表达及相互关系和意义

目的　探讨c erbB 2、p53和nm2 3蛋白在乳腺癌组织中的表达与乳腺癌临床病理参数、雌激素受体 (ER)、孕激素受体 (PR)的关系。方法　应用免疫组化ABC法对 5 5例乳腺癌组织中的c erbB 2、p53和nm2 3蛋白表达进行检测。结果　 5 5例乳腺癌中c erbB 2、p53及nm2 3的阳性率分别为 49 1 % (2 7/5 5 )、47 3 % (2 6 /5 5 )和 49 1 % (2 7/5 5 ) ,c erbB 2和p53蛋白在乳腺癌中的阳性率与肿瘤病理分级及淋巴结转移有显著意义 (P <0 0 5 ) ,与雌孕激素受体状况呈负相关 (P <0 0 1 )。nm2 3蛋白在乳腺癌中的阳性率与肿瘤病理分级、淋巴结转移有密切的关系 (p <0 0 5 ) ,与雌孕激素受体状呈正相关 (p <0 0 1 )。 70 9% (3 9/5 5 )肿瘤有上述蛋白的异常表达 ,其中 49 1 % (2 7/5 5 )的肿瘤同时有多个蛋白异常表达。结论　肿瘤的多因素分析比单因素分析更有价值 ,癌基因c erbB 2、nm2 3和抑癌基因p53蛋白的表达异常及协同作用在乳腺癌的发生发展中起重要使用     

肿瘤浸润淋巴细胞免疫组织化学研究

应用免疫组织化学PAP法,对26例常见恶性肿瘤冰冻组织切片中肿瘤浸润淋巴细胞(TIL)进行了原位分析,以了解TIL的组成及分布等原位特征。结果显示:(1)TIL中主要为CD_3~ 细胞,其中CD_4~ 相似文献   

Characterization of Pathogenic Human MSH2 Missense Mutations Using Yeast as a Model System: A Laboratory Course in Molecular Biology

This work describes the project for an advanced undergraduate laboratory course in cell and molecular biology. One objective of the course is to teach students a variety of cellular and molecular techniques while conducting original research. A second objective is to provide instruction in science writing and data presentation by requiring comprehensive laboratory reports modeled on the primary literature. The project for the course focuses on a gene, MSH2, implicated in the most common form of inherited colorectal cancer. Msh2 is important for maintaining the fidelity of genetic material where it functions as an important component of the DNA mismatch repair machinery. The goal of the project has two parts. The first part is to create mapped missense mutation listed in the human databases in the cognate yeast MSH2 gene and to assay for defects in DNA mismatch repair. The second part of the course is directed towards understanding in what way are the variant proteins defective for mismatch repair. Protein levels are analyzed to determine if the missense alleles display decreased expression. Furthermore, the students establish whether the Msh2p variants are properly localized to the nucleus using indirect immunofluorescence and whether the altered proteins have lost their ability to interact with other subunits of the MMR complex by creating recombinant DNA molecules and employing the yeast 2-hybrid assay.     

Stem cells: A dormant volcano within our body?

Stem cells constitute an important class of cells in the body that have the ability to perpetuate themselves and remain in an uncommitted state by a process of self-renewal as well as to specialize into new cell types. Their ability to differentiate into multiple cell types marks the tremendous potential of stem cells for tissue repair and organ regeneration. Realization of this potential is rapidly opening up unexplored avenues for curing several ailments including diabetes and neurodegenerative diseases. However, very little is understood about the basic biology of stem cells. For example, what are the biochemical tags that allow us to identify stem cell? Which are the signaling pathways that regulate their function? How does the environment (niche) influence major decisions made by stem cell? Is stem cell therapy the end to all woes, or is there a flip side to the story? This article aims to give an overview of the current status of stem cell research and raises some alarming issues related to stem cell-based therapies.     

Deregulation of microRNA expression in thyroid tumors简

MicroRNAs (miRNAs or miRs) are endogenous non-coding RNAs that negatively regulate gene expression by binding to the 3′ non-coding regions of target mRNAs, resulting in their cleavage or blocking their translation. miRNAs may have an impact on cell differentiation, proliferation, and survival, and their deregulation can be inclined to diseases and cancers, including thyroid tumors. The purpose of this review is to summarize the existing findings of deregulated miRNAs in different types of thyroid tumors and to exhibit their potential target genes, especially to demonstrate those involved in tumor invasion and metastasis. In addition, new findings of circulating miRNA expression profiles, single nucleotide polymorphism (SNP) in thyroid tumors, and the correlation of somatic mutations with deregulated miRNA expression in thyroid tumors were all included in this review.     

Endoplasmic reticulum stress is involved in retinal injury induced by repeated transient spikes of intraocular pressure

Clinically, a large proportion of glaucoma patients undergo repeated intraocular pressure (IOP) spike (Spike IOP) attacks during their sleep, which may facilitate retinopathy. In this study, we established a mouse model of repeated transient Spike IOP to investigate the direct damage to the retina following Spike IOP attacks, and elucidated the underlying molecular mechanism. We analyzed the changes in the number of retinal ganglion cells (RGCs) via immunofluorescence. Thereafter, we detected retinal cell apoptosis via terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) staining, and performed RNA sequencing (RNA-seq) to reveal the underlying molecular mechanism. Finally, we validated the expression of key molecules in the endoplasmic reticulum (ER) stress pathway using quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis. Results revealed a time-dependent RGC loss in Spike IOP, evidenced by a reduction in the number of Brn3a-positive RGCs in experimental eyes following a 7-d continuous treatment with Spike IOP. In addition, TUNEL staining indicated that apoptosis of retinal cells started in the outer nuclear layer (ONL), and then spread to the ganglion cell layer (GCL) with time. RNA-seq analysis revealed that ER stress might be involved in Spike IOP-induced retinal injury. This result was corroborated by western blot, which revealed upregulation of ER stress-related proteins including binding immunoglobulin protein/glucose-regulated protein 78 (BiP/GRP78), phosphorylated inositol-requiring enzyme 1 (p-IRE1), unspliced X-box-binding protein 1 (XBP1-u), spliced X-box-binding protein 1 (XBP1-s), phosphorylated c-Jun N-terminal kinase (p-JNK), C/EBP-homologous protein (CHOP), and B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax). These findings indicate that repeated IOP transients are detrimental to the retina, while ER stress plays an important role in retinal cell apoptosis in this situation. Notably, repeated Spike IOP among glaucoma patients is a crucial factor for progressive retinopathy.

     

阿拉伯半乳糖蛋白与植物体细胞胚胎发生的关系

植物离体细胞胚性状态的保持对于许多植物的离体再生起着决定性的作用.阿拉伯半乳糖蛋白（Arabinogalatan proteins,AGPs）广泛存在于植物组织和器官中,对植物的生长发育起着重要的作用.单克隆抗体法、βGlcY（-βD-glucosyl-Yariv regent,β-葡萄糖基-Yariv试剂）试剂沉淀AGPs法和直接添加外源AGPs的方法被广泛用到AGPs功能的研究上.通过这些研究方法,发现AGPs可通过影响植物细胞的胚性状态而影响植物的体细胞胚胎发生,进一步影响植株离体再生.     

Telomerase RNA and telomerase activity in trophoblastic tumors

To gain better understanding of telomerase’s possible role in the carcinogenesis of gestational trophoblastic tumors, the authors conducted RT-PCR amplification-based analysis and carried out telomeric repeat amplification to determine the levels of the human telomerase RNA (hTR) and that of telomerase enzymatic activity itself in 43 normal human placental tissues, 35 gestational trophoblastic tumor tissues and three choriocarcinoma cell lines. hTR was expressed in malignant gestational trophoblastic tumor tissues as well as choriocarcinoma cell lines. The results showed that hTR of early placenta villi and a part of hydatidiform mole were positive. But relatively low levels of the hTR could be found in placental tissues. Telomerase enzymatic activity was strongly positive in 32 of the 35 (91.4%) gestational trophoblastic tumor tissues and all the three choriocarcinoma cell lines. The enzymatic activity of telomerase itself was detectable at relatively low lelves in 14 of the 21 (66.7%) early placental villi, only three of the 22 (13.6%) term placenta were weakly positive. These results suggest that telomerase activity may be correlated with the development of trophoblastic tumors, and so, may be a useful diagnostic marker for detecting the existence of malignant trophoblastic cells. Project (39670753) supported by NSFC     

溶酶体的研究近况

溶酶体是动物细胞中的细胞器,内含多种高浓度的酸性水解酶,目前已证实所含水解酶多达60多种,其主要功能是在细胞内起消化作用,对机体也有防御功能,并能清除衰老细胞和多余的细胞器。溶酶体酶出现异常而造成的疾病目前已发现多种,由于溶酶体对机体代谢有重要意义,因此对其的研究日益受到重视。     

线粒体形态和功能与细胞骨架间关系的研究进展

线粒体为细胞的各种生命活动提供能量,也是细胞凋亡的重要参与者.线粒体功能多样与其运动性较强以及形态具有可塑性相适应,往往被运输到细胞的特定位置.线粒体的运输主要是通过与能影响其形态和功能的各种细胞骨架蛋白相互作用而实现.越来越多的证据显示:线粒体以细胞骨架蛋白为轨道而得以运动,与此同时细胞骨架通过各种非特异性的途径调节了线粒体的形态和功能.综述了细胞骨架与线粒体形态和功能关系的研究进展,并对发展前景进行了预测.