Chromosomal and genetic abnormalities in benign and malignant meningiomas using DNA microarray

Abstract

Background: Meningioma is the commonest brain tumor and many genetic abnormalities, such as the loss of chromosome 22q and the mutation of NF2, have been reported.

Methods: These classical abnormalities were detected using Southern blot, PCR, fluorescence in situ hybridization and comparative genomic hybridization, but these methods examine only very limited regions or limited mapping resolution of the tumor genome. In this study, we used DNA microarray assay, which detects numerous genetic abnormalities simultaneously and analyses a global assessment of molecular events in meningioma cells. We studied 31 meningiomas by GenoSensor Array 300 in order to detect the chromosomal aberrations and genetic abnormalities in the whole genome.

Results: This study demonstrated not only classical chromosomal aberration, such as loss of chromosome 22q in 19 meningiomas (61.3%), but also new genetic characteristics of meningiomas, such as amplification of MSH2 in 16 meningiomas (51.6%), deletion of GSCL in 13 meningiomas (41.9%) and deletion of HIRA in seven meningiomas (22.6%).

Conclusions: These results suggest that DNA microarray assay is useful in research for the genetic characters of meningiomas and understanding tumorigenesis.     

Cyr61 expression in osteosarcoma indicates poor prognosis and promotes intratibial growth and lung metastasis in mice

Osteosarcoma is the most frequent primary malignant bone tumor in children and adolescents with a high propensity for lung metastasis, the major cause of disease‐related death. Reliable outcome‐predictive markers and targets for osteosarcoma metastasis‐suppressing drugs are urgently needed for more effective treatment of metastasizing osteosarcoma, which has a current mean 5‐year survival rate of approximately 20%. This study investigated the prognostic value and the biological relevance of the extracellular matrix‐associated growth factor Cyr61 of the CCN family of secreted proteins in osteosarcoma and metastasis. The prognostic value of Cyr61 was assessed with Kaplan‐Meier analyses based on Cyr61 immunostaining of a tissue microarray of osteosarcoma biopsies collected from 60 patients with local or metastatic disease. Effects of Cyr61 overexpression on intratibial tumor growth and lung metastasis of the low metastatic human SaOS‐2 osteosarcoma cell line were examined in severe combined immunodeficiency (SCID) mice. Cyr61‐provoked signaling was studied in vitro in nonmanipulated SaOS‐2 cells. Cyr61 immunostaining of osteosarcoma tissue cores correlated significantly (p = 0.02) with poor patient survival. Mice intratibially injected with Cyr61‐overexpressing SaOS‐2 cells showed faster tumor growth and an increase in number and outgrowth of lung metastases and consequently significantly (p = 0.0018) shorter survival than mice injected with control SaOS‐2 cells. Cyr61‐evoked PI‐3K/Akt/GSK3β signaling in SaOS‐2 cells resulted in a subcellular redistribution of the cell cycle inhibitor p21^Cip1/WAF1. Cyr61 has considerable potential as a novel marker for poor prognosis in osteosarcoma and is an attractive target for primary tumor‐ and metastases‐suppressing drugs. © 2012 American Society for Bone and Mineral Research     

脑胶质瘤相关新基因的聚类分析在其分子病理学分类中的意义

目的 探讨人脑胶质瘤发生发展中相关基因的表达及功能,初步建立基于基因表达谱的胶质瘤分子病理学分类方法。方法 用含13939种人类基因的BioStarH140S型表达谱芯片,以正常脑组织及胶质瘤组织总RNA制备的探针杂交芯片;ScanArray 4000扫描芯片,提取正常脑组织及胶质瘤组织差异基因并行生物信息分析,对部分新基因行Northern杂交、原位杂交等功能研究;Hierarchical聚类对差异基因进行特征提取,进行初步胶质瘤分子病理分类。结果 在正常脑组织与18例不同级别胶质瘤组织中筛选出1200条(8.61％)差异基因,其中395条(2．83％)基因尚未登录GeneBank,胶质组织瘤中348条基因表达上调,852条下调,信息分析与细胞信号传导等多类基因密切相关;Northern、原位杂交显示新基因与胶质瘤密切相关;聚类发现微管相关蛋白、黏附素超家族蛋白、细胞外基质相关基因等与分子分型相关,基于基因表达谱的分子病理分类与依据细胞形态的病理学分类基本一致,且更能反映胶质瘤发生发展的内在本质。结论 胶质瘤发生发展存在多类基因表达改变,表达谱芯片对胶质瘤分类具有特异性高、重复性好、样本量少的特点,基因表达谱及相关新基因的发现和分子病理学分类有助于阐明胶质瘤分子病理学机制。     

Changes of MicroRNA Profile and MicroRNA‐mRNA Regulatory Network in Bones of Ovariectomized Mice

Growing evidence shows the possibility of a role of microRNAs (miRNA) in regulating bone mass. We investigated the change of miRNAs and mRNA expression profiles in bone tissue in an ovariectomized mice model and evaluated the regulatory mechanism of bone mass mediated by miRNAs in an estrogen‐deficiency state. Eight‐week‐old female C3H/HeJ mice underwent ovariectomy (OVX) or sham operation (Sham‐op), and their femur and tibia were harvested to extract total bone RNAs after 4 weeks for microarray analysis. Eight miRNAs (miR‐127, ‐133a, ‐133a*, ‐133b, ‐136, ‐206, ‐378, ‐378*) were identified to be upregulated after OVX, whereas one miRNA (miR‐204) was downregulated. Concomitant analysis of mRNA microarray revealed that 658 genes were differentially expressed between OVX and Sham‐op mice. Target prediction of differentially expressed miRNAs identified potential targets, and integrative analysis using the mRNA microarray results showed that PPARγ and CREB pathways are activated in skeletal tissues after ovariectomy. Among the potential candidates of miRNA, we further studied the role of miR‐127 in vitro, which exhibited the greatest changes after OVX. We also studied the effects of miR‐136, which has not been studied in the context of bone mass regulation. Transfection of miR‐127 inhibitor has enhanced osteoblastic differentiation in UAMS‐32 cells as measured by alkaline phosphatase activities and mRNA expression of osteoblast‐specific genes, whereas miR‐136 precursor has inhibited osteoblastic differentiation. Furthermore, transfection of both miR‐127 and miR‐136 inhibitors enhanced the osteocyte‐like morphological changes and survival in MLO‐Y4 cells, whereas precursors of miR‐127 and ‐136 have aggravated dexamethasone‐induced cell death. Both of the precursors enhanced osteoclastic differentiation in bone marrow macrophages, indicating that both miR‐127 and ‐136 are negatively regulating bone mass. Taken together, these results suggest a novel insight into the association between distinct miRNAs expression and their possible role through regulatory network with mRNAs in the pathogenesis of estrogen deficiency–induced osteoporosis. © 2014 American Society for Bone and Mineral Research.     

Bioinformatics and microarray analysis of microRNA expression profiles of murine embryonic stem cells,neural stem cells induced from ESCs and isolated from E8·5 mouse neural tube

Abstract

To better understand whether microRNAs (miRNAs) are involved in the self-renewal of stem cells and fate determination of neural stem cells and to identify the miRNA expression patterns of different neural stem cells (NSC) in vitro and in vivo, we examined miRNA expression profiles of murine embryonic stem cells (ESC), NSC induced from ESC and isolated from E8·5 mouse neural tube (E8·5-NSC) using microarray technique. It was found that a total of 40 miRNAs had similar expression level in all the three cells [false discovery rate (FDR)=0, fold change <3·0]. Moreover, q-PCR showed that some members of miR-106b and miR-17–92 families were expressed in the ESC, NSC induced from ESC (ESC-NSC) and hematopoietic stem cells (HSC). Bioinformatical analysis showed that 'stemness genes' (p21/CDKN1A, p57/CDKN1C and PTEN) were putative targets of miR-106b and miR-17–92 families. A total of 95 miRNAs were found to experience significant change (FDR=0, fold change >5·0) when the ESC differentiated into NSC. On the basis of miRNA, mRNA expression variance and predicted target genes of miRNA, we formulated a bioinformatical model for miRNA control of ESC-NSC differentiation. Then, the miRNA expression pattern was compared between NSC obtained in vitro and in vivo, and it was found that only 8% of miRNAs were different between the two NSCs. This study suggested that miR-106b and miR-17–92 families may promote the renewal of stem cells by targeting PTEN, p21/CDKN1A and p57/CDKN1C. Some miRNAs may play a key role in gene re-programming during ESC-NSC differentiation, and a substantial homogeneity exists between NSCs derived in vitro and those in vivo.