Prostaglandin E(2) metabolism is activated in Schwann cell lines derived from human NF1 malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumors (MPNSTs) are characteristic of Neurofibromatosis type 1 (NF1), a human genetic disorder affecting approximately 1 in 3000 individuals. The absence of neurofibromin in Schwann cells results in hyperactivation of Ras, which contributes to Schwann cell hyperplasia. However, additional intracellular abnormalities in Schwann cells might contribute to the malignancy. We now report that cell lines derived from MPNSTs secrete elevated levels of prostaglandin E(2) (PGE(2)), express higher levels of phosphorylated mitogen-activated protein kinase (MAPK), phosphorylated cytosolic phospholipaseA(2) (cPLA(2)) and cyclooxygenase 2 (COX-2) when compared to normal adult human Schwann cells (nhSCs). PCR analysis reveals that NF1 MPNST cell lines express mRNA for both EP2 and EP4 prostaglandin E2 receptors, whereas nhSCs express only the EP4 receptor. COX-2 inhibitors and PGE(2) receptor antagonists decrease the proliferation of MPNST cell lines. These results indicate that prostaglandin metabolism is activated in MPNSTs and might contribute to tumor growth in NF1.     

RNAi及DNA芯片分析肝癌细胞系中受DNMT3B调控的下游基因

为揭示DNA甲基转移酶3B（DNMT3B）在肝癌中是否参与了肿瘤的发生,应用Western blotting及细胞免疫化学方法分析DNMT3B蛋白在人的正常肝细胞株、肝癌癌旁细胞株及肝癌癌细胞株中的表达。构建了DNMT3B的RNAi稳定表达的重组载体,并转染人肝癌细胞株SMMC-7721中。以半定量RT-PCR及Western blotting分别鉴定DNM73B RNAi表达载体对内源性DNMT3B的抑制效率。用高通量的cDNA基因芯片分析了SMMC-7721中DNMT3B抑制后有影响的下游基因谱。结果显示,DNMT3B在肝癌细胞株中的表达水平明显高于肝癌癌旁和正常肝细胞株。DNMT3B的RNAi稳定表达重组载体转染SMMC-7721细胞株2个月后,观察到DNMT3B明显受到抑制。cDNA基因芯片分析发现,DNMT3B抑制后诱导26条基因表达下调,115条基因表达上调,包括一些发育相关基因以及肿瘤相关基因,如SNCG、NOTCH1、MBD3、WNT11、MAOA、FACL4等。提示DNMT3B的高表达可能与肝癌的发生有关,并以调控其他相关基因的表达而起作用,包括与发育相关的重要基因。     

应用cDNA微阵列技术研究EB病毒LMP1介导的鼻咽癌中转移相关基因的表达

探讨EB病毒基因组编码的癌蛋白LMP1对鼻咽癌细胞中转移相关基因表达的影响.采用蛋白质印迹法检测在强力霉素(Dox)诱导下,鼻咽癌细胞系pTet-on-LMP1 HNE2(L7细胞)中LMP1表达的时效和量效关系.应用cDNA微阵列技术建立诱导性LMP1介导鼻咽癌细胞中转移相关基因差异表达谱;运用RT-PCR验证cDNA微阵列筛选差异基因表达的可靠性.与LMP1不表达的L7细胞比较,LMP1高表达的L7细胞中7个基因的表达显著上调,12个基因的表达显著下调.随机选择其中4个基因进行RT-PCR,结果显示,这些基因表达阳性,且与微阵列中的变化趋势一致.LMP1可能通过激活和/或抑制一些转移相关基因的表达而参与鼻咽癌转移过程.     

Combination of PCR subtraction and cDNA microarray for differential gene expression profiling.

PCR subtraction hybridization has been used effectively to enrich and single out differentially expressed genes. However identification of these genes by means of cloning and sequencing individual cDNAs is a tedious and lengthy process. In this report, an attempt has been made to combine the use of PCR select cDNA subtraction hybridization and cDNA microarrays to identify differentially expressed genes using a nonradioactive chemiluminescent detection method. mRNA from human prolactin (hPRL) or human prolactin antagonist (hPRL-G129R) treated and non-treated breast cancer cells was isolated, and cDNAs were synthesized and used for the PCR subtraction to enrich the differentially expressed genes in the treated cells. The PCR-amplified and subtracted cDNA pools were purified and labeled using the digoxigenin method. Labeled cDNAs were hybridized to a human apoptosis cDNA microarray membrane and identified by chemiluminescence. The results suggest that the strategy of combining all three methods will allow for a more efficient, nonradioactive way of identifying differentially expressed genes in target cells.     

Cross-species application of cDNA microarrays to profile gene expression using UV-induced melanoma in Monodelphis domestica as the model system

This study established the utility of cross-species application of the cDNA microarray technique for investigating differential gene expression. Using both total RNA and mRNA samples recovered from two opossum cell lines derived from UVB-induced melanoma, we analyzed expression of ca. 4400 genes on the human DermArray DNA microarrays. The signals generated on the DermArrays were clear, strong, and reproducible. A cDNA dot blot consisting of differentially expressed genes representative of different functional clusters was used to validate the DermArray results. We also cloned a Monodelphis gene, keratin 18 (KRT18), and characterized its expression patterns in tumor samples of different progression stages. Up-regulated expression was observed for the KRT18 gene in advanced melanomas, a finding consistent with the DermArray analysis. These results provide evidence that cross-species application of cDNA microarrays is a useful strategy for investigating gene expression patterns in animal models for which species-specific cDNA microarrays are not available.     

FGF ligand family mRNA expression profile for mouse preimplantation embryos, early gestation human placenta, and mouse trophoblast stem cells

Signaling by fibroblast growth factor (FGF) is essential is for trophoblast stem (TS) cells and preimplantation embryos. FGF4 provides essential signaling, but the expression of the complete set of 23 FGF family members has not been analyzed. Here, semi-quantitative RT-PCR and microarray analyses were used to define expression of all FGF ligand mRNA. RT-PCR was done for developmentally important FGF subfamilies, FGF10/FGF22 and FGF8/FGF17/FGF18 as well as FGF11. FGF4 and FGF18 are detected at highest levels by RT-PCR and microarrays. FGF10 was detected at low levels in both assays. FGF11 was detected at moderate levels by microarray, but not by RT-PCR. FGF17 was detected at low levels by array and moderate levels by RT-PCR. FGF8 and FGF22 were detected by RT-PCR, but not by microarrays during late cleavage divisions. FGF8, FGF5, and FGF9 were detected in the oocyte by microarray. FGF2, FGF3, and FGF7 were not detected by RT-PCR or microarrays and FGF13, FGF14, and FGF23 were not detected by microarray. Since a major role of FGF is to maintain TS cells, we tested human and mouse placental cell lines and early gestation human placenta for expression of FGF ligands. Expression in mouse TS cells was compared with preimplantation embryos, and human placental cell line expression was compared with human placenta, to infer which ligands are expressed in placental lineage vs. other cell lineages. The data suggest that human and mouse placenta share FGF18 and its high expression suggests preimplantation and early placental function.     

Genes that code for T cell signaling proteins establish transcriptional regulatory networks during thymus ontogeny

Gene expression profiling by cDNA microarrays during murine thymus ontogeny has contributed to dissecting the large-scale molecular genetics of T cell maturation. Gene profiling, although useful for characterizing the thymus developmental phases and identifying the differentially expressed genes, does not permit the determination of possible interactions between genes. In order to reconstruct genetic interactions, on RNA level, within thymocyte differentiation, a pair of microarrays containing a total of 1,576 cDNA sequences derived from the IMAGE MTB library was applied on samples of developing thymuses (14-17 days of gestation). The data were analyzed using the GeneNetwork program. Genes that were previously identified as differentially expressed during thymus ontogeny showed their relationships with several other genes. The present method provided the detection of gene nodes coding for proteins implicated in the calcium signaling pathway, such as Prrg2 and Stxbp3, and in protein transport toward the cell membrane, such as Gosr2. The results demonstrate the feasibility of reconstructing networks based on cDNA microarray gene expression determinations, contributing to a clearer understanding of the complex interactions between genes involved in thymus/thymocyte development.     

Proteome analysis of human pancreatic cancer cell lines with highly liver metastatic potential by antibody microarray

Antibody microarrays have been successfully used to determine relative abundance of key proteins in various cancers and other diseases. We have previously showed liver metastatic-related genes between the metastatic pancreatic cancer line (SW1990HM) and its parental line (SW1990). In this study, we searched for potential markers for metastatic progression using antibody microarrays. The SpringBio Antibody Microarrays were used to analysis the different proteomes between SW1990HM and SW1990 cells. A standard ≥2.0-fold cutoff value was used to determine differentially expressed proteins and Western blotting analysis further confirmed the results. Antibody microarrays revealed that 40 proteins were reproducibly altered more than 2-fold between the selected variant and its parental counterpart; 14 of the proteins were up-regulated, and 26 were down-regulated. Most of the up-regulated proteins (7/14) play a role in tumor signal transduction, while a number of down-regulated proteins (10/26) function in cell differentiation; this might be crucial for pancreatic cancer metastasis. Four dysregulated proteins were validated by western blotting in the cell lines. Interestingly, the up-regulation of Glucagon and down-regulation of Prolactin were further confirmed in the culture supernatants by western blotting. These proteomic data are valuable for understanding pancreatic cancer metastasis and searching for potential markers of metastatic progression.     

A comprehensive approach for establishment of the platform to analyze functions of KIAA proteins II: public release of inaugural version of InGaP database containing gene/protein expression profiles for 127 mouse KIAA genes/proteins.

The inaugural version of the InGaP database (Integrative Gene and Protein expression database; http://www.kazusa.or.jp/ingap/index.html) is a comprehensive database of gene/protein expression profiles of 127 mKIAA genes/proteins related to hypothetical ones obtained in our ongoing cDNA project. Information about each gene/protein consists of cDNA microarray analysis, subcellular localization of the ectopically expressed gene, and experimental data using anti-mKIAA antibody such as Western blotting and immunohistochemical analyses. KIAA cDNAs and their mouse counterparts, mKIAA cDNAs, were mainly isolated from cDNA libraries derived from brain tissues, thus we expect our database to contribute to the field of neuroscience. In fact, cDNA microarray analysis revealed that nearly half of our gene collection is predominantly expressed in brain tissues. Immunohistochemical analysis of the mouse brain provides functional insight into the specific area and/or cell type of the brain. This database will be a resource for the neuroscience community by seamlessly integrating the genomic and proteomic information about the mouse KIAA genes/proteins.