title: Tumor interstitial fluid and gastric cancer metastasis: an experimental study to verify the hypothesis of "tumor-phlegm microenvironment".
abstract: OBJECTIVE
  To extract tumor interstitial fluid (TIF) from MKN-45 gastric cancer which is similar to "muddy phlegm" in Chinese medicine and observe influences of MKN-45 tumor interstitial fluid (MKN-45 TIF) intervention on metastasis of gastric cancer and on the expressions of vascular endothelial growth factor (VEGF), kinase insert domain containing receptor (KDR), epithelial-cadherin (E-cad), cyclooxygenase-2 (COX-2), intercellular adhesion molecule-1 (ICAM-1) and telomerase genes and proteins in primary tumor tissue.
  
  
  METHODS
  An MKN-45 tumor-bearing model was established in 50 nude mice. The modeled animals were equally randomized to 5 groups: the simple tumor-bearing group (model group), the normal saline (NS) via tail vein injection (i.v.) group (NS i.v. group), MKN-45 TIF i.v. group (TIF i.v. group), NS intraperitoneal injection (i.p.) group (NS i.p. group), and MKN-45 TIF i.p. group (TIF i.p. group). The TIF and NS intervention groups received injection (i.p. or i.v.) of MKN-45 TIF or NS twice a week, 0.2 mL at a time. After 8 weeks, the primary tumors were removed, weighed and HE stained to observe tumor metastasis. The primary tumor tissues were analyzed by immunohistochemistry and real-time quantitative PCR to detect expressions of VEGF, KDR, E-cad, COX-2, ICAM-1, and telomerase genes and proteins in different groups.
  
  
  RESULTS
  There were significant differences in tumor weight between TIF intervention groups and the model and NS intervention groups. Tumor metastasis was observed in all 5 groups, but the tumor metastasis rate in TIF intervention groups was significantly higher than those in the model and NS intervention groups. The gene and protein expressions of gastric cancer-related factors VEGF, KDR, COX-2, ICAM-1 and telomerase were unregulated while the gene and protein expressions of E-cad were downregulated in TIF intervention groups.
  
  
  CONCLUSIONS
  TIF promotes tumor growth, invasion and metastasis of gastric cancer. These findings provide preliminary experimental clues for verifying the hypothesis of "tumor-phlegm microenvironment".
authors.affiliation: Institute of Traditional Chinese Medicine Research, Chinese People's Liberation Army General Hospital, Beijing, China.
authors.forename: Da-zhi
authors.initials: DZ
authors.lastname: Sun
authors.forename: Jian-peng
authors.initials: JP
authors.lastname: Jiao
authors.forename: Da-wei
authors.initials: DW
authors.lastname: Ju
authors.forename: Min
authors.initials: M
authors.lastname: Ye
authors.forename: Xuan
authors.initials: X
authors.lastname: Zhang
authors.forename: Jing-yu
authors.initials: JY
authors.lastname: Xu
authors.forename: Ye
authors.initials: Y
authors.lastname: Lu
authors.forename: Jin
authors.initials: J
authors.lastname: He
authors.forename: Pin-kang
authors.initials: PK
authors.lastname: Wei
authors.forename: Ming-hui
authors.initials: MH
authors.lastname: Yang
mesh_terms: D000818:Animals; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D045604:Extracellular Fluid / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000556:secondary*; D019098:Telomerase / Q000235:genetics / Q000378:metabolism; D059016:Tumor Microenvironment / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism
chemical_list: D015820:Cadherins; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D018799:Intercellular Adhesion Molecule-1; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2; D040301:Vascular Endothelial Growth Factor Receptor-2; D019098:Telomerase