title: Expressions of urokinase-type plasminogen activator, its receptor and plasminogen activator inhibitor-1 in gastric cancer cells and effects of Helicobacter pylori.
abstract: OBJECTIVE
  Destruction of the extracellular matrix is essential for tumor invasion and metastasis. The relationship between Helicobacter pylori (H. pylori) infection and destruction of the extracellular matrix is not yet clear. Urokinase-type plasminogen activator (uPA) plays an important role in the destruction of the extracellular matrix and basement membrane. Urokinase-type plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1(PAI-1) appear to be associated with these processes. To clarify the role of H. pylori infection in the processes of destruction of the extracellular matrix and basement membrane in cancerous tissue, the effect of H. pylori on the expressions of uPA, uPAR and PAI-1 in cancer cells was investigated.
  
  
  METHODS
  Gastric cancer cell lines (MKN45, KATO-III) were co-cultured with H. pylori standard strain (NCTC11637), cagA-negative strain and clinical isolated strain. The specific inductions of uPA, uPAR and PAI-1 mRNA were examined by reverse transcription-polymerase chain reaction (RT-PCR) amplification. The secreted uPA antigen was measured by enzyme-linked immunosorbent assay (ELISA). To evaluate the role of transcription factor NF-kappaB in uPA and uPAR gene transcription with H. pylori stimulation, the effect of NF-kappaB inhibitor MG132 on H. pylori-induced uPA and uPAR mRNA expression was examined.
  
  
  RESULTS
  The expressions of both uPA and uPAR mRNAs in the gastric cancer cell lines (MKN45 and KATO- III) were increased markedly (uPA mRNA; MKN45: 12-fold, KATO-III: 5-fold) (uPAR mRNA; MKN45: 3-fold, KATO-III: 3-fold) with H. pylori NCTC11637 strain stimulation, whereas the expression levels of uPA and uPAR mRNA did not increase with cagA-negative strain stimulation. These cancer cell lines slightly secreted uPA antigen into the culture medium, and the amount of uPA antigen increased dramatically by stimulation with H. pylori NCTC11637 and cagA-positive clinical isolated strains. These gastric cancer cell lines also slightly secreted PAI-1 antigen into the culture medium, and the amount of PAI-1 antigen was not affected by H. pylori NCTC11637 stimulation. H. pylori-induced uPA and uPAR mRNA expressions were strongly down-regulated by pretreatment with MG132 in both cell lines.
  
  
  CONCLUSIONS
  The results of this study indicated the possibility that cagA-positive H. pylori may play an important role not only in tissue remodeling, angiogenesis and wound healing but also in the process of degradation of the extracellular matrix breakdown, tumor invasion and metastasis by inducing uPA and uPAR complex in the gastric cancer cells.
authors.affiliation: Fifth Department of Internal Medicine, Tokyo Medical University, Japan. junnki@dg.mbn.or.jp
authors.forename: Junichi
authors.initials: J
authors.lastname: Iwamoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mizokami
authors.forename: Kimiko
authors.initials: K
authors.lastname: Takahashi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakajima
authors.forename: Toshiya
authors.initials: T
authors.lastname: Ohtsubo
authors.forename: Syuhei
authors.initials: S
authors.lastname: Miura
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Narasaka
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takeyama
authors.forename: Takayuki
authors.initials: T
authors.lastname: Omata
authors.forename: Koichi
authors.initials: K
authors.lastname: Shimokobe
authors.forename: Masanori
authors.initials: M
authors.lastname: Ito
authors.forename: Hisashi
authors.initials: H
authors.lastname: Takehara
authors.forename: Takeshi
authors.initials: T
authors.lastname: Matsuoka
mesh_terms: D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015536:Down-Regulation; D016481:Helicobacter Infections / Q000453:epidemiology / Q000235:genetics; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics / Q000378:metabolism*; D011336:Probability; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000382:microbiology / Q000473:pathology; D014407:Tumor Cells, Cultured; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D017395:Plasminogen Activator Inhibitor 1; D012329:RNA, Bacterial; D012333:RNA, Messenger; D014568:Urokinase-Type Plasminogen Activator