title: Expression of aquaporin 5 increases proliferation and metastasis potential of lung cancer.
abstract: Water channel aquaporin 5 (AQP5) is highly expressed at the apical membrane of alveolar type I epithelial cells and confers high osmotic water permeability. AQP5 is also expressed in lung cancer tissue. Previous studies showed there was an up-regulation of AQP5 expression in cancer tissue compared to surrounding normal tissue. In addition, expression of AQP5 in lung cancer tissue was associated with poor prognosis. Herein, we tested the role of AQP5 in lung cancer oncogenesis and development. Lung cancer cells with different expression of AQP5 were used to study cell proliferation and migration, two important parameters for tumour cell biology. We found enhanced proliferation and migration potential in cancer cells with high AQP5 expression, while reduced proliferation and metastasis potential in cancer cells with low AQP5 expression. Oncogene analysis showed significantly increased PCNA and c-myc expression in AQP5 transfected cells. AQP5 transfected cells also showed significant increased MUC5AC mucin expression, which might contribute to the enhanced metastasis potential of lung cancer. AQP5 overexpression resulted in enhanced activation of the epidermal growth factor receptor (EGFR), extracellular receptor kinase (ERK1/2), and p38 mitogen-activated protein kinase (p38 MAPK) pathway in cancer cells. Moreover, deletion of AQP5 demonstrated decreased activation of the EGFR/ERK/p38 MAPK pathway in AQP5 knockout mice lungs, while deletion of AQP1 or AQP3 did not exhibit significant changes on activation of the EGFR/ERK/p38 MAPK pathway in lung tissue. In conclusion, our results provide evidence for AQP5-facilitated lung cancer cell proliferation and migration, possibly through activation of the EGFR/ERK/p38 MAPK signalling pathway, but why AQP5 but not other aquaporin expression affects the EGFR/ERK/p38 MAPK pathway still needs further exploration.
authors.affiliation: Department of Pulmonary Medicine, Research Institute of Respiratory Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, PR China.
authors.forename: Ziqiang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Chen
authors.forename: Yuanlin
authors.initials: Y
authors.lastname: Song
authors.forename: Pinghai
authors.initials: P
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Hu
authors.forename: Chunxue
authors.initials: C
authors.lastname: Bai
mesh_terms: D000818:Animals; D051402:Aquaporin 5 / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement; D049109:Cell Proliferation; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism*; D010539:Permeability; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D051402:Aquaporin 5; D009363:Neoplasm Proteins; D018809:Proliferating Cell Nuclear Antigen; D066246:ErbB Receptors; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases