title: Association of EMP1 with gastric carcinoma invasion, survival and prognosis.
abstract: The aim of this study was to determine the expression and function of epithelial membrane protein 1 (EMP1) in gastric carcinoma. Gastric samples were taken from cancer lesions and adjacent normal tissue in gastric cancer patients immediately after endoscopic biopsy. A portion of the sample was either fixed in 4% paraformaldehyde and embedded in paraffin for immunohistochemistry or stored in liquid nitrogen for western blotting. In order to determine protein expression of EMP1 in gastric cancer (n=65) and normal tissue (n=27), semi-quantitative immunohistochemistry and western blotting were utilized. For in vitro studies, the human gastric cancer cell line SGC-7901 was maintained in RPMI-1640 medium supplemented with 10% fetal bovine serum. Recombinant lentivirus mediated overexpression of EMP1 in SGC-7901 cells was quantified with quantitative polymerase chain reaction (qPCR) and western blotting. Control SGC-7901 cells were transfected with an empty vector. To further study the effect of EMP1 overexpression in SGC-7901 cells, cell proliferation, cell apoptosis and migration and invasion assays were conducted. The expression of EMP1 was significantly lower in gastric cancer tissue compared to normal tissue using both immunohistochemistry (41.5 vs. 70.4% of tissues, P<0.05) and western blotting (0.153 ± 0.012 vs. 0.626 ± 0.058, P<0.05). Decreased expression of EMP1 was significantly correlated with tumor invasion, lymph node metastasis, clinical stage and histological grade of patients with gastric cancer (P<0.05). According to Kaplan-Meier analysis, low EMP1 expression correlated significantly with poor overall 5-year survival (47.4 vs. 70.3% survival, P<0.05). SGC-7901 cells transfected with EMP1 had a lower survival fraction, higher cell apoptosis (13.2 ± 1.5% vs. 2.2 ± 0.5%, P<0.05), significant decrease in migration and invasion (157.0 ± 16.0 and 112.0 ± 12.0, respectively vs. 243.0 ± 21.0 and 203.0 ± 19.0, respectively, P<0.05), higher caspase-9 (0.501 ± 0.050 vs. 0.114 ± 0.010, P<0.05) and lower VEGFC protein expression 0.135 ± 0.011 vs. 0.619 ± 0.074, P<0.05) relative to cells not transfected with EMP1. Low EMP1 expression in gastric cancer is associated with increased disease severity, suggesting that EMP1 may be a negative regulator of gastric cancer.
authors.affiliation: Department of Chemoradiotherapy, Tangshan People's Hospital, Tangshan 063000, P.R. China.
authors.forename: Guogui
authors.initials: G
authors.lastname: Sun
authors.affiliation: Department of Gastrointestinal Surgery, The Second Tangshan Hospital, Tangshan 063000, P.R. China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhao
authors.affiliation: Department of Endocrinology, Tangshan Workers Hospital, Tangshan 063000, P.R. China.
authors.forename: Yifang
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Radiotherapy, The Military General Hospital of Beijing PLA, Beijing 100700, P.R. China.
authors.forename: Yadi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Radiotherapy, The Fourth Hospital of Hebei Medical University, Shijiazhuang 050017, P.R. China.
authors.forename: Congrong
authors.initials: C
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D045744:Cell Line, Tumor; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D056726:Genetic Association Studies; D006801:Humans; D008207:Lymphatic Metastasis / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000235:genetics* / Q000473:pathology; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D055815:Young Adult
chemical_list: D009363:Neoplasm Proteins; D011956:Receptors, Cell Surface; C097051:epithelial membrane protein-1