title: MiRNA-3978 regulates peritoneal gastric cancer metastasis by targeting legumain.
abstract: Gastric cancer incidence and mortality are among the highest in China, with majority of the mortality related to peritoneal metastasis of gastric cancer. Treatment is limited to radical resection, which is impeded by incidence of metastasis at time of initial diagnosis, thus making it imperative to identify diagnostic and prognostic biomarkers. Legumain, a lysosomal cysteine endopeptidase of the asparaginyl endopeptidase family, has been shown to be overexpressed in patients with metastatic gastric cancer disease and its expression was positively correlated to both disease progression and outcome. However, the mechanism of legumain expression is currently unknown. Legumain overexpression was found to occur at the level of post transcriptional gene regulation. In situ prediction algorithms identified legumain as a putative target of miR-3978. MiR-3978 was significantly decreased in peritoneal metastatic tissue specimens and in MKN45 cells that mimic peritoneal metastasis features. Reporter assays using LGMN (encoding legumain) 3' untranslated region (UTR) showed that miR-3978 interacted with the wild-type but not miR-3978-seed mutant. Ectopic expression of miR-3978 mimic in the MKN45 cell line significantly decreased proliferation and suppressed in vitro migration and invasion. The miR-3978 mimic inhibited gastric carcinoma and metastatic progression in a mice model by regulating legumain protein expression. Inverse correlation of LGMN mRNA and miR-3978 levels in 20 gastric patients at different stages of metastatic disease confirmed the same. Cumulatively, our results indicate that loss of miR-3978 leads to increased expression of legumain, which indicates that miR-3978might be a biomarker for peritoneal metastasis in patients with gastric cancer.
authors: Department of General Surgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130012, China.
authors: Yi
authors: Y
authors: Zhang
authors: Department of General Surgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130012, China.
authors: Yuan-Yu
authors: YY
authors: Wu
authors: Department of General Surgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130012, China.
authors: Jun-Nan
authors: JN
authors: Jiang
authors: Department of General Surgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130012, China.
authors: Xue-Song
authors: XS
authors: Liu
authors: Department of General Surgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130012, China.
authors: Fu-Jian
authors: FJ
authors: Ji
authors: Department of General Surgery, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130012, China.
authors: Xue-Dong
authors: XD
authors: Fang
mesh_terms: D020413:3' Untranslated Regions; D000328:Adult; D000368:Aged; D000818:Animals; D001665:Binding Sites; D045744:Cell Line, Tumor; D002465:Cell Movement; D019295:Computational Biology; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D030541:Databases, Genetic; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D009154:Mutation; D009361:Neoplasm Invasiveness; D010534:Peritoneal Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000556:secondary; D015398:Signal Transduction; D013274:Stomach Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D013997:Time Factors; D014162:Transfection; D047368:Tumor Burden; D000099240:Asparaginyl Endopeptidase
chemical_list: D020413:3' Untranslated Regions; D003546:Cysteine Endopeptidases; D035683:MicroRNAs; D000099240:Asparaginyl Endopeptidase
keywords: gastric cancer; legumain; metastasis; miRNA-3978