TRPV5 and TRPV6 in Ca(2+) (re)absorption: regulating Ca(2+) entry at the gate

Expression of TRPV5 and TRPV6 in development of colonic adenocarcinoma

AIM: To investigate the expression of transient receptor potential cation channel, subfamily V, member 5 (TRPV5) and TRPV6 in the development of colon adenocarcinoma and to discuss the role of TRPV5 and TRPV6 in the carcinogenesis of this malignancy.

METHODS: TRPV5, TRPV6 and Ki-67 expression was examined by immunohistochemical staining, RT-PCR, and Western blot in 20 colonic hyperplastic polyp, 20 colonic adenoma (40 for immunohistochemical staining), 20 colonic adenocarcinoma, and 20 normal colonic mucosal tissues obtained by endoscopic biopsy, surgical resection or endoscopic polypectomy. The relationship between the expression of TRPV6 and TRPV5 and the carcinogenesis of colon adenocarcinoma was then assessed.

RESULTS: TRPV5 and TRPV6 expression was detectable in the normal colon, colonic polyp and colonic cancer tissues, mainly localized in the cytoplasm. The expression of Ki-67 increased with the increase in TRPV5 and TRPV6 expression (P < 0.05). TRPV5 and TRPV6 proteins and mRNAs were weakly or not expressed in normal intestinal mucosa and non-adenoma polyps (P > 0.05), but were highly expressed in colon adenoma and colon adenocarcinoma (P < 0.05). TRPV5 and TRPV6 expression had a significant correlation with histological type (P < 0.05). In the colonic mucosa, TRPV5 expression was lower than TRPV6 expression (P < 0.05).

CONCLUSION: TRPV5 and TRPV6 show high expression in colon adenoma and adenocarcinoma, and Ki-67 expression is correlated with TRPV5 and TRPV6 expression. TRPV5 and TRPV6 might be related with the extent of tissue proliferation and the risk of malignant transformation of polyps. TRPV5 and TRPV6 may play an important role in the carcinogenesis and development of colonic adenocarcinoma.