Expression and function of carboxypeptidase E (CPE) in human breast adenocarcinoma

Objective: To observe the expression and processing of carboxypeptidase E (CPE) mediated neuroendocrinopeptide in human breast adenocarcinoma. Methods: By using RT-PCR, immunohistochemistry, ELISA, and Western blot techniques, the expression profiles of CPE and growth hormone releasing hormone (GHRH) gene and protein were investigated between 42 human breast tumor tissues and 21 tumor-adjacent normal ones. Results: The expression level of CPE gene in the breast adenocarcinoma tissues was 1024±237, while it was 805±83 in the tumor-adjacent normal tissues (P<0.01). The CPE protein in the breast tumor tissues showed higher expression than in the tumor-adjacent normal tissues (P<0.01). The expression level of GHRH gene in the breast adenocarcinoma tissues was 1522±457, while it was 1067±437 in the tumor-adjacent normal tissues (P<0.01). The GHRH protein was up-regulated in the tumor tissues (P<0.01). Conclusions: The high expressions of CPE and GHRH suggest that there is a strong CPE mediated neuroendocrinopeptide posttranslational processing in the breast tumor cells.