title: Macrophages facilitate coal tar pitch extract-induced tumorigenic transformation of human bronchial epithelial cells mediated by NF-κB.
abstract: OBJECTIVE
  Chronic respiratory inflammation has been associated with lung cancer. Tumor-associated macrophages (TAMs) play a critical role in the formation of inflammation microenvironment. We sought to characterize the role of TAMs in coal tar pitch extract (CTPE)-induced tumorigenic transformation of human bronchial epithelial cells and the underlying mechanisms.
  
  
  METHODS
  The expression of TAMs-specific CD68 in lung cancer tissues and paired adjacent tissues from cancer patients was determined using immunostaining. Co-culture of human bronchial epithelial cells (BEAS-2B) and macrophage-like THP-1 cells were conducted to evaluate the promotive effect of macrophages on CTPE-induced tumorigenic transformation of BEAS-2B cells. BEAS-2B cells were first treated with 2.4 µg/mL CTPE for 72 hours. After removal of CTPE, the cells were continuously cultured either with or without THP-1 cells and passaged using trypsin-EDTA. Alterations of cell cycle, karyotype, colony formation in soft agar and tumor xenograft growth in nude mice of BEAS-2B cells at passages 10, 20 and 30, indicative of tumorigenecity, were determined, respectively. In addition, mRNA and protein levels of NF-κB in BEAS-2B cells were measured with RT-PCR and western blot, respectively. B(a)P was used as the positive control.
  
  
  RESULTS
  The over-expression of TAMs-specific CD68 around lung tumor tissues was detected and associated with lung cancer progression. The tumorigenic alterations of BEAS-2B cells including increase in cell growth rate, number of cells with aneuploidy, clonogenicity in soft agar, and tumor size in nude mice in vivo occurred at passage 10, becoming significant at passages 20 and 30 of the co-culture following CTPE removal in compared to BEAS-2B cells alone. In addition, the expression levels of NF-κB in BEAS-2B cells were positively correlated to the malignancy of BEAS-2B cells under different conditions of treatment.
  
  
  CONCLUSIONS
  The presence of macrophages facilitated CTPE-induced tumorigenic transformation of BEAS-2B cells, which may be mediated by NF-κB.
authors.affiliation: Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, Henan, China. feifeifeng9@gmail.com
authors.forename: Feifei
authors.initials: F
authors.lastname: Feng
authors.forename: Yiming
authors.initials: Y
authors.lastname: Wu
authors.forename: Shaofeng
authors.initials: S
authors.lastname: Zhang
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Lijuan
authors.initials: L
authors.lastname: Qin
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Wu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yan
authors.forename: Weidong
authors.initials: W
authors.lastname: Wu
mesh_terms: D000328:Adult; D000782:Aneuploidy; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D001980:Bronchi / Q000473:pathology*; D002452:Cell Count; D002460:Cell Line; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000187:drug effects / Q000473:pathology*; D003033:Coal Tar; D045424:Complex Mixtures; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D003033:Coal Tar; D045424:Complex Mixtures; D016328:NF-kappa B; D012333:RNA, Messenger; C067980:CD68 antigen, human; D000097382:CD68 Molecule