Expression Of Aquaporin5 In Human Colorectal Carcinoma

Objective: To investigate expression of aquaporin5 (AQP5) in human colorectal carcinoma tissues and analyze its clinical significance.Method: Human colorectal carcinoma tissues were acquired immediately after operation from November 2006 to December 2007. The expression of aquaporin5 in human colorectal carcinoma tissue and paraneoplastic normal tissue was detected by reverse transcription PCR (RT-PCR), Western-blot, Immunohistochemistry.Results: Findings by RT-PCR indicated that the AQP 5 mRNA expressed in colorectal carcinoma tissues was significantly higher than that expressed in paraneoplastic normal tissues (carcinoma tissues vs. normal tissues: 0.42±0.08 vs. 0.02±0.00, P<0.05). Weston blot showed that the AQP5 protein band was located at 35 kD. Furthermore, the AQP5 protein was significantly higher expressed in colorectal carcinoma tissues compared with paraneoplastic normal tissues (carcinoma tissues vs. normal tissues: 0.74±0.12 vs. 0.01±0.00, P<0.05). Immunohistochemistry showed that the AQP5 was mainly expressed in colorectal carcinoma cell membrane and cytoplasm. However, no AQP5 was detected in paraneoplastic normal tissues. The expression of AQP5 was related with the loss of tumor differentiation, lymph node metastasis and TNM stage (P<0.05).Conclusion: The overexpression of AQP5 in human colorectal carcinoma tissue plays an important role in colorectal carcinogenesis, progression and metastasis; The expression of AQP5 was related with the loss of tumor differentiation, lymph node metastasis and TNM stage. Furthermore, the AQP5 inhibtors may be regarded as novel targets of anti-cancer therapy.