title: Identification of microRNAs associated with lymphangiogenesis in human gastric cancer.
abstract: OBJECTIVE
  Lymphatic metastasis is a primary cause of gastric cancer-related death, yet factors governing tumor cell lymphatic metastasis have not been fully elucidated. MicroRNAs (miRNAs) are a recently discovered class of regulatory, non-coding RNAs, some of which are involved in gastric cancer progression. However, little is known about which miRNA contributes to the lymphatic metastasis in human gastric cancer. This prompted us to find the significant miRNAs associated with lymphangiogenesis in human gastric cancer.
  
  
  METHODS
  We screened vascular endothelial growth factor C (VEGF-C) expression in several gastric cancer cell lines as well as in the immortalized human gastric mucosal cell line GES-1, by real-time reverse transcriptase PCR (qRT-PCR). The gastric cancer cell lines MKN-45 and SGC-7901, which have commonly been cultured with human lymphatic endothelial cells (HLECs) in vitro, promoted tube formation of HLECs following transformation with a VEGF-C expression vector. Using microarrays, we identified a panel of differentially expressed miRNAs in HLECs that had been co-cultured with VEGF-C-transformed gastric cancer cells compared with non-transformed gastric cancer cells. A subset of miRNAs was further validated using qRT-PCR.
  
  
  RESULTS
  We found altered expression of miRNAs in HLECs co-cultured with lymphangiogenesis-inducing VEGF-C-transformed gastric cancer cells, with 47 up-regulated and 42 down-regulated miRNAs. These findings were confirmed by qRT-PCR of selected miRNAs. Furthermore, several miRNAs were differentially expressed in patients with positive lymphatic metastasis of the primary gastric tumor. Up-regulated miRNAs included miR-648, miR-5002-3p, miR-4754, miR-4760-5p, miR-4491, miR-4252, miR-5007-3p, and miR-647; and down-regulated miRNAs included miR-3178, miR-593-5p, miR-4485, miR-135a-3p, miR-17, miR-1469, and miR-124-5p.
  
  
  CONCLUSIONS
  Several lymphangiogenesis-related miRNAs are significantly altered during lymphatic metastasis of gastric cancer.
authors.affiliation: Department of Gastrointestinal Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, China.
authors.forename: B
authors.initials: B
authors.lastname: Yang
authors.forename: C
authors.initials: C
authors.lastname: Jing
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: X
authors.initials: X
authors.lastname: Guo
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: R
authors.initials: R
authors.lastname: Xu
authors.forename: L
authors.initials: L
authors.lastname: Peng
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: L
authors.initials: L
authors.lastname: Li
mesh_terms: D045744:Cell Line, Tumor; D006801:Humans; D042583:Lymphangiogenesis / Q000235:genetics*; D008207:Lymphatic Metastasis / Q000235:genetics*; D035683:MicroRNAs / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology*; D014162:Transfection
chemical_list: D035683:MicroRNAs