Background: An oncogenic capacity of aquaporins (AQPs) has been recently proposed. They are channel-forming membrane proteins that function as osmotically driven transepithelial and transcellular water. Most recently, overexpression of several AQPs has been reported in different types of human cancer, which indicates that AQPs may play an important role in human carcinogenesis.
Methods: In this study, we were going to elucidate the involvement of aquaporin 1 and 4 (AQP1,4) in the metastasis of lung cancer.
Results: Expression of AQP1,4 was examined by immunohistochemistry on the twenty lung cancer tissues. AQP1,4 were overexpressed in 65% (13 of 20) and 70% (14 of 20) of adenocarcinoma, while the normal lung tissues were negative. We next investigated the roles of AQP1,4 in the invasion of lung cancer cells by transwell migration assays. It is indicated that migration cells of the AQP1-shRNA or AQP4-shRNA were reduced significantly in comparison to the controls (AQP1- shRNA vs. AQP1-CTL, 5.6% vs. 15.9%, p<0.05; AQP4- shRNA vs. AQP4-CTL, 8.9% vs. 14.8%, p<0.05). From this study, we found AQP1 and AQP4 in lung cancer cell extravasation and spread, which may provide a functional explanation for the expression of AQP1 and AQP4 in lung cancer tissues and lung cancer cell lines.
Conclusions: Although further details on the molecular function of AQP1 or 4 related to tumorigenesis remain to be elucidated, our results suggest a potential role of AQP1 or 4 as novel therapeutic targets for the management of lung cancer.
DOI: Clin. Lab. 2012;58:75-80