title: The effect of proteoglycans inhibited by RNA interference on metastatic characters of human salivary adenoid cystic carcinoma.
abstract: BACKGROUND
  Salivary adenoid cystic carcinoma (SACC) is one of the most common malignancies of salivary gland. Recurrence or/and early metastasis is its biological properties. In SACC, neoplastic myoepithelial cells secrete proteoglycans unconventionally full of the cribriform or tubular and glandular structures of SACC. Literatures have demonstrated that extracellular matrix provided an essential microenvironment for the biological behavior of SACC. However, there is rare study of the effect of proteoglycans on the potential metastasis of SACC.In this study, human xylosyltransferase-I (XTLY-I) gene, which catalyzes the rate-limited step of proteoglycans biosynthesis, was knocked down by RNA interference (RNAi) to inhibit the proteoglycans biosynthesis in SACC cell line with high tendency of lung metastasis (SACC-M). The impact of down-regulated proteoglycans on the metastasis characters of SACC-M cells was analyzed and discussed. This research could provide a new idea for the clinical treatment of SACC.
  
  
  METHODS
  The eukaryotic expression vector of short hairpin RNA (shRNA) targeting XTLY-I gene was constructed and transfected into SACC-M cells. A stably transfectant cell line named SACC-M-WJ4 was isolated. The XTLY-I expression was measured by real-time PCR and Western blot; the reduction of proteoglycans was measured. The invasion and metastasis of SACC-M-WJ4 cells were detected; the effect of down-regulated proteoglycans on the potential lung metastasis of nude mice was observed, respectively.
  
  
  RESULTS
  The shRNA plasmid targeting XTLY-I gene showed powerful efficiency of RNAi. The mRNA level of target gene decreased by 86.81%, the protein level was decreased by 80.10%, respectively. The silence of XTLY-I gene resulted in the reduction of proteoglycans significantly in SACC-M-WJ4 cells. The inhibitory rate of proteoglycans was 58.17% (24 h), 66.06% (48 h), 57.91% (72 h), 59.36% (96 h), and 55.65% (120 h), respectively. The reduction of proteoglycans suppressed the adhesion, invasion and metastasis properties of SACC-M cells, and decreased the lung metastasis of SACC-M cells markedly either.
  
  
  CONCLUSIONS
  The data suggested that the silence of XTLY-I gene in SACC-M cells could suppress proteoglycans biosynthesis and secretion significantly. The reduction of proteoglycans inhibited cell adhesion, invasion and metastasis of SACC-M cells. There is a close relationship between proteoglycans and the biological behavior of SACC.
authors.affiliation: Department of Oral Pathology, Key Laboratory of Stomatology, College of Stomatology, Hebei Medical University, Hebei Province, No, 383 Zhongshan East Road, Shijiazhuang, PR China. shihong_hb@163.com
authors.forename: Hong
authors.initials: H
authors.lastname: Shi
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.forename: Fusheng
authors.initials: F
authors.lastname: Dong
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Hexiang
authors.initials: H
authors.lastname: Li
authors.forename: Yali
authors.initials: Y
authors.lastname: Hou
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D001483:Base Sequence; D003528:Carcinoma, Adenoid Cystic / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D055785:Gene Knockdown Techniques; D018390:Gene Targeting; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D041681:NIH 3T3 Cells; D009362:Neoplasm Metastasis; D010430:Pentosyltransferases / Q000037:antagonists & inhibitors* / Q000235:genetics; D011509:Proteoglycans / Q000037:antagonists & inhibitors* / Q000235:genetics; D034622:RNA Interference / Q000502:physiology; D034741:RNA, Small Interfering / Q000494:pharmacology* / Q000627:therapeutic use; D012468:Salivary Gland Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays; D000097608:UDP Xylose-Protein Xylosyltransferase
chemical_list: D000970:Antineoplastic Agents; D010430:Pentosyltransferases; D011509:Proteoglycans; D034741:RNA, Small Interfering; D000097608:UDP Xylose-Protein Xylosyltransferase