title: Molecular Response of Human Monocytes Following Interaction with Colon Cancer Cells by Pre-treatment with Low-dose Lipopolysaccharide.
abstract: OBJECTIVE
  The increased mRNA expression of chemotaxis- and angiogenesis-related factors in human monocytes following interaction with colon cancer cells has been shown to be suppressed by pre-treatment with low-dose lipopolysaccharide (LPS) (100 pg/ml). It has been demonstrated that low-dose LPS reduced the expression of RelB, a member of the nuclear factor (NF)-κB transcription factor family, in mouse macrophages and the NF-κB signaling pathway was important for tumor initiation and growth in tumor-associated macrophages. In addition, the signal transducer and activator of transcription 3 (STAT3) regulated innate immunity via Toll-like receptor (TLR)4 signaling. In the present study, the mRNA expression of signaling pathway- and suppression-related genes in human monocytes following a low-dose LPS treatment and subsequent interaction with colon cancer cells was investigated, in order to assess the molecular response.
  
  
  METHODS
  The human monocyte cell line THP-1 was treated with LPS and, subsequently, co-cultured with the human colon cancer cell line DLD-1. The mRNA expression of various genes was then analyzed using quantitative real-time polymerase chain reaction (PCR).
  
  
  RESULTS
  The mRNA expression of RelB, STAT3, interleukin (IL)-10 and transforming growth factor (TGF)-β in THP-1 cells following interaction with DLD-1 cells was suppressed by pre-treatment with low-dose LPS (100 pg/ml).
  
  
  CONCLUSIONS
  Treating human monocytes with low-dose LPS may be useful for suppressing tumor progression and may be valuable for maintaining homeostasis.
authors.affiliation: Department of Medical Technology, School of Life and Environmental Science, Azabu University, Kanagawa, Japan hondat@azabu-u.ac.jp.
authors.forename: Teruko
authors.initials: T
authors.lastname: Honda
authors.affiliation: Department of Integrated and Holistic Immunology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inagawa
mesh_terms: D045744:Cell Line, Tumor; D018920:Coculture Techniques; D003110:Colonic Neoplasms / Q000276:immunology*; D018450:Disease Progression; D020869:Gene Expression Profiling; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000008:administration & dosage*; D008264:Macrophages / Q000276:immunology; D009000:Monocytes / Q000276:immunology*; D012333:RNA, Messenger / Q000096:biosynthesis; D050796:STAT3 Transcription Factor / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000276:immunology; D051841:Transcription Factor RelB / Q000096:biosynthesis; D016212:Transforming Growth Factor beta / Q000096:biosynthesis
chemical_list: C556062:IL10 protein, mouse; D008070:Lipopolysaccharides; C497593:RELB protein, human; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D016212:Transforming Growth Factor beta; D016753:Interleukin-10; D051841:Transcription Factor RelB
keywords: RelB; STAT3; co-culture; colon cancer cell; low-dose lipopolysaccharide; monocyte