AQP5: A novel biomarker that predicts poor clinical outcome in colorectal cancer

Abstract

Abstract. The aquaporins (AQPs) are water channel proteins that exhibit several properties related to tumor development. However, the expression and clinical significance of AQP5 in colorectal cancer, particularly the correlation with circulating tumor cells (CTCs), has not been elucidated. The aim of the present study was to determine whether or not the expression of AQP5 is a strong prognostic biomarker for colorectal cancer. The results showed that of 45 tumor specimens, 14 (31.1%) had high levels of expression of AQP5, 29 (64.4%) exhibited a moderate (intermediate) level of staining, and 2 (4.4%) had an absence of AQP5 staining. AQP5 was only occasionally detected in para-neoplastic [3/45 (6.67%)] and normal tissues [3/45 (6.67%)]. AQP5 protein overexpression frequently accompanied gene amplification detection with fluorescence in situ hybridization (FISH). Moreover, AQP5 expression in colorectal cancer cells was upregulated compared to normal colon cells. AQP5 overexpression was also associated with TNM stage (P=0.002), lymph node metastasis (P=0.016), and distant metastasis (P=0.000). The relationships between age, gender, histologic grade and tumor size with expression of AQP5 were not significant (P>0.05). A positive correlation between the number of CTCs and AQP5 expression (P<0.05) was demonstrated. In addition, patients who did not express AQP5 had a superior cumulative survival rate compared to patients with AQP5 positivity. AQP5 may be used as a novel biomarker for colorectal cancer aggressiveness and metastasis, but it does not reflect drug resistance.

Down‐regulation of aquaporin 5‐mediated epithelial‐mesenchymal transition and anti‐metastatic effect by natural product Cairicoside E in colorectal cancer

“…Increasing evidences had demonstrated that AQPs were involved in the progression of different cancers, such as colon cancer, lung cancer, gastric cancer, and breast cancer . In particular, AQP5 was found to be implicated in the incidence and progression of CRC, and closely related to CRC metastasis . However, there is no evidence to explain the effect of AQP5 on EMT of CRC to date.…”

“…37,44,45 In particular, AQP5 was found to be implicated in the incidence and progression of CRC, and closely related to CRC metastasis. 23 However, there is no evidence to explain the effect of AQP5 on EMT of CRC to date. In this study, we observed that overexpression of AQP5 promoted the mesenchymallike phenotype and EMT process in SW480 and HCT-116 cells as well as the low metastatic HT-29 CRC cells.…”

“…A number of studies have demonstrated that AQP5 promoted the proliferation and metastasis of CRC . Moreover, considerable clinical data suggest that high expression of AQP5 predicted tumor metastasis and poor prognosis of CRC . Nonetheless, the molecular mechanisms of AQP5 involved in CRC metastasis remain elusive.…”

“…[19][20][21] Moreover, considerable clinical data suggest that high expression of AQP5 predicted tumor metastasis and poor prognosis of CRC. [22][23][24][25] Nonetheless, the molecular mechanisms of AQP5 involved in CRC metastasis remain elusive.…”

RNA interference-mediated silencing of aquaporin (AQP)-5 hinders angiogenesis of colorectal tumor by suppressing the production of vascular endothelial growth factor

“…AQP5 as a critical member of AQP family was first cloned from rat submandibular gland [7], and has been shown to contribute to the progression of various types of malignant tumors [8][9][10][11][12]. Recent studies reveal AQP5 as an oncogene involved in carcinogenesis [13] and suggest it as a novel prognostic biomarker for various types of tumors [14,15]. Interestingly, an abnormal overexpression of AQP5 has been found in colorectal cancer samples, which is linked to the aggressiveness and metastasis [15,16].…”