Yuji Yamamoto1,2, Naohide Oue3, Ryuichi Asai1,4, Narutaka Katsuya1, Naohiro Uraoka1, Naoya Sakamoto1, Kazuhiro Sentani1, Kazuaki Tanabe2, Hideki Ohdan2, Wataru Yasui1. 1. Department of Molecular Pathology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan. 2. Department of Gastroenterological and Transplant Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan. 3. Department of Molecular Pathology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan, naoue@hiroshima-u.ac.jp. 4. Department of Surgical Oncology, Graduate School of Medicine, Gifu University, Gifu, Japan.
Abstract
OBJECTIVES: Esophageal cancer is the sixth most common malignancy worldwide. Signal peptidase complex 18 (SPC18) protein, which is encoded by the SEC11A gene, is one of the subunits of the signal peptidase complex and plays an important role in the secretion of proteins including transforming growth factor α (TGF-α). In this study, we investigated the significance of SPC18 expression in human esophageal squamous cell carcinoma (ESCC). METHODS: SPC18 expression was examined by immunohistochemistry. RNA interference was used to inhibit SPC18 expression in ESCC cell lines. To examine cell viability, we performed 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. The effects of SPC18 inhibition on epidermal growth factor receptor (EGFR) signaling were analyzed by Western blot. RESULTS: In total, 46 (50%) of 92 ESCC cases were positive for SPC18. SPC18 staining was observed more frequently in stage II/III/IV cases than in stage I cases (p = 0.028). We found that SPC18 expression was significantly associated with increased cancer-specific mortality (p = 0.006, log-rank test). SPC18 expression was frequently found in EGFR-positive cases compared with EGFR-negative cases. Cell proliferation and EGFR signaling were inhibited by SPC18 knockdown. CONCLUSION: Specific inhibitors of SPC18 may be promising anticancer drugs for patients with ESCC.
OBJECTIVES: Esophageal cancer is the sixth most common malignancy worldwide. Signal peptidase complex 18 (SPC18) protein, which is encoded by the SEC11A gene, is one of the subunits of the signal peptidase complex and plays an important role in the secretion of proteins including transforming growth factor α (TGF-α). In this study, we investigated the significance of SPC18 expression in humanesophageal squamous cell carcinoma (ESCC). METHODS:SPC18 expression was examined by immunohistochemistry. RNA interference was used to inhibit SPC18 expression in ESCC cell lines. To examine cell viability, we performed 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. The effects of SPC18 inhibition on epidermal growth factor receptor (EGFR) signaling were analyzed by Western blot. RESULTS: In total, 46 (50%) of 92 ESCC cases were positive for SPC18. SPC18 staining was observed more frequently in stage II/III/IV cases than in stage I cases (p = 0.028). We found that SPC18 expression was significantly associated with increased cancer-specific mortality (p = 0.006, log-rank test). SPC18 expression was frequently found in EGFR-positive cases compared with EGFR-negative cases. Cell proliferation and EGFR signaling were inhibited by SPC18 knockdown. CONCLUSION: Specific inhibitors of SPC18 may be promising anticancer drugs for patients with ESCC.