Functional analysis of human beta defensin-1 in prostate cancer

2682 Defensins are small 3-4 kDa peptides clustered on the short arm of chromosome 8 (segment 8p22-8p23) that have been shown to have antimicrobial activities. It has been demonstrated that there are chromosomal deletions in the 8pter-p23 regions in a variety of cancers including prostatic carcinoma. Additionally, there is a positive correlation between deletions in 8pter-p23 region and poor prognosis in prostate cancer. Furthermore, it has been postulated that there may be three separate potential tumor suppressor genes located in the 8pter-8p23 region. However, no specific gene has been identified and nothing is known about their function in prostate cancer. Human β-defensin-1 (hBD-1) is located at chromosome position 8p23.2. We have recently demonstrated that there is cancer-specific loss of hBD-1in malignant prostatic clinical samples, while high levels of expression are maintained in benign regions. Overall, 82% of prostate cancers exhibit either complete loss of hBD-1 protein expression or only minimal expression, while the adjacent benign epithelium retained expression in all cases. We report here the further characterization of hBD-1. In vitro functional analysis demonstrates that hBD-1 has cytotoxic activity against prostate cancer cells. These studies further suggest that hBD-1 may have tumor suppressive activities in cancer.