title: Astrocyte elevated gene-1 upregulates matrix metalloproteinase-9 and induces human glioma invasion.
abstract: The poor prognosis of malignant gliomas is largely attributed to their highly invasive nature. The molecular mechanism underlying the invasiveness of glioma cells, however, remains to be elucidated. The present study found that astrocyte elevated gene-1 (AEG-1) was upregulated in human glioma cell lines and glioma tissues compared with normal astrocytes and brain tissues. AEG-1 was found to be upregulated in 265 of 296 (89.5%) glioma sections, and the AEG-1 expression level significantly correlated with clinicopathologic stages of gliomas. Ectopic expression or short hairpin RNA silencing of AEG-1 significantly enhanced or inhibited, respectively, the invasive ability of glioma cells. At the molecular level, we showed that upregulated AEG-1 in glioma cells interacted with matrix metalloproteinase-9 (MMP-9) promoter and transactivated MMP-9 expression, whereas knockdown of AEG-1 expression reduced the level of MMP-9. Two regions in MMP-9 promoter were found to be involved in the interaction with AEG-1. Suppression of endogenous MMP-9 abrogated the effects of AEG-1 on invasiveness. Consistent with these observations, immunostaining analysis revealed a significant correlation between the expressions of AEG-1 and MMP-9 in a cohort of clinical glioma samples. Moreover, intracranial xenografts of glioma cells engineered to express AEG-1 were highly invasive compared with the parental cells and expressed high level of MMP-9. Collectively, these findings provide evidence that AEG-1 contributes to glioma progression by enhancing MMP-9 transcription and, hence, tumor cell invasiveness, and underscore the importance of AEG-1 in glioma development and progression.
authors.affiliation: Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Liu
authors.forename: Jueheng
authors.initials: J
authors.lastname: Wu
authors.forename: Zhe
authors.initials: Z
authors.lastname: Ying
authors.forename: Baixue
authors.initials: B
authors.lastname: Chen
authors.forename: Anjia
authors.initials: A
authors.lastname: Han
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Liang
authors.forename: Libing
authors.initials: L
authors.lastname: Song
authors.forename: Jie
authors.initials: J
authors.lastname: Yuan
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Mengfeng
authors.initials: M
authors.lastname: Li
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000473:pathology*; D015815:Cell Adhesion Molecules / Q000096:biosynthesis / Q000235:genetics*; D045744:Cell Line, Tumor; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D005910:Glioma / Q000201:enzymology / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D016601:RNA-Binding Proteins; D014158:Transcription, Genetic; D014183:Transplantation, Heterologous; D015854:Up-Regulation
chemical_list: D015815:Cell Adhesion Molecules; C483039:MTDH protein, human; D008565:Membrane Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D020780:Matrix Metalloproteinase 9