title: Continual exposure to cigarette smoke extracts induces tumor-like transformation of human nontumor bronchial epithelial cells in a microfluidic chip.
abstract: BACKGROUND
  Heavy cigarette smoking-related chronic obstructive pulmonary disease is an independent risk factor for lung squamous carcinoma. However, the mechanisms underlying the malignant transformation of bronchial epithelial cells are unclear.
  
  
  METHODS
  In our study, human tumor-adjacent bronchial epithelial cells were obtained from 10 cases with smoking-related chronic obstructive pulmonary disease and lung squamous carcinoma and cultured in an established microfluidic chip for continual exposure to cigarette smoke extracts (CSE) to investigate the potential tumor-like transformation and mechanisms. The integrated microfluidic chip included upstream concentration gradient generator and downstream cell culture chambers supplied by flowing medium containing different concentrations of CSE.
  
  
  RESULTS
  Our results showed that continual exposure to low doses of CSE promoted cell proliferation whereas to high doses of CSE triggered cell apoptosis. Continual exposure to CSE promoted reactive oxygen species production in human epithelial cells in a dose-dependent manner. More importantly, continual exposure to low dose of CSE promoted the epithelial-to-mesenchymal transition process and anchorage-independent growth, and increased chromosome instability in bronchial epithelial cells, accompanied by activating the GRP78, NF-κB, and PI3K pathways.
  
  
  CONCLUSIONS
  The established microfluidic chip is suitable for primary culture of human tumor-adjacent bronchial epithelial cells to investigate the malignant transformation. Continual exposure to low doses of CSE promoted tumor-like transformation of human nontumor bronchial epithelial cells by inducing reactive oxygen species production and activating the relevant signaling.
authors.affiliation: *Department of Respiratory Medicine, the Second Affiliated Hospital of Dalian Medical University; †Department of Histol&Embryol, Dalian Medical University, Dalian, China; ‡Department of Respiratory Medicine, the Affiliated Zhongshan Hospital of Dalian University; §Key laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian; ‖Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical College, Wenzhou, Zhejiang, China; ¶The Charles Institute of Dermatology, School of Medicine and Medical Science, University College Dublin, Ireland; and #Department of Respiratory & Critical Care Medicine, the People's Hospital of Peking University, Beijing, China.
authors.forename: Encheng
authors.initials: E
authors.lastname: Li
authors.forename: Zhiyun
authors.initials: Z
authors.lastname: Xu
authors.forename: Fen
authors.initials: F
authors.lastname: Liu
authors.forename: Huiling
authors.initials: H
authors.lastname: Wang
authors.forename: Jiabin
authors.initials: J
authors.lastname: Wen
authors.forename: Shujuan
authors.initials: S
authors.lastname: Shao
authors.forename: Lichuan
authors.initials: L
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Chong
authors.initials: C
authors.lastname: Liu
authors.forename: Jianxin
authors.initials: J
authors.lastname: Lu
authors.forename: Wenxin
authors.initials: W
authors.lastname: Wang
authors.forename: Zhancheng
authors.initials: Z
authors.lastname: Gao
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001980:Bronchi; D002294:Carcinoma, Squamous Cell / Q000209:etiology / Q000473:pathology*; D049109:Cell Proliferation / Q000187:drug effects; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D043171:Chromosomal Instability / Q000187:drug effects; D045424:Complex Mixtures / Q000633:toxicity*; D000091342:Endoplasmic Reticulum Chaperone BiP; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology / Q000473:pathology*; D046210:Microfluidic Analytical Techniques; D016328:NF-kappa B / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D029424:Pulmonary Disease, Chronic Obstructive / Q000209:etiology / Q000473:pathology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D012906:Smoke / Q000009:adverse effects*; D012907:Smoking / Q000009:adverse effects*; D014026:Nicotiana / Q000737:chemistry / Q000633:toxicity
chemical_list: D045424:Complex Mixtures; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D017382:Reactive Oxygen Species; D012906:Smoke; C000717247:HSPA5 protein, human