Androgen-deprivation therapy (ADT) is the standard treatment for metastatic prostate cancer. One factor that has been implicated in the metastatic process is the cell adhesion molecule N-cadherin. In this study, we investigated if the expression of N-cadherin was influenced by androgen deprivation and was associated with metastasis in prostate cancer. The effect of androgen deprivation on N-cadherin expression was initially studied in androgen-dependent (AD) LNCaP and androgen-independent (AI) LNCaP-19 and PC-3 prostate cancer cell lines. Expression of N-cadherin increased in the absence of androgens in AI LNCaP-19 primary tumors and metastases and also in vitro, but not in AI PC-3 tumors, indicating a possible involvement of the androgen receptor in the regulation of N-cadherin. N-cadherin was absent in AD LNCaP tumors. No clear associations between N-cadherin and factors related with epithelialmesenchymal transition or neuroendocrine differentiation could be established. In addition, N-cadherin was evaluated by immunohistochemistry in human prostate tumors. Expression of N-cadherin was more frequently found in tumors from patients treated with ADT than in tumors from patients with no prior hormonal treatment. N-cadherin expression was also associated with metastasis and Gleason score. Furthermore, increased N-cadherin was detected in prostate cancer biopsies already 3 months after initiation of ADT when tumors were in a regressed state. In summary the results indicate that androgen deprivation induces N-cadherin in prostate tumors. Moreover, N-cadherin was increased in castration-resistant tumors in patients with established metastases. This might indicate that castration induces molecular alterations in the tumor cells, resulting in a more invasive and metastatic phenotype.

LNCaP-19 shows characteristics resembling those of androgen-independent prostate cancer. An increased MVD and changed vessel morphology in the tumor, makes it an interesting model system for studies regarding angiogenesis in the context of the acquisition of androgen independence.

The results show that LNCaP-19 mimics hormone refractory prostate cancer and therefore is an excellent tool for studies on androgen-independent cancer and invasion. This study shows that transition into an androgen-independent state correlates with several proinvasive alterations.

Expression of several genes associated with angiogenesis was altered during transition into androgen-independency. Among these, a significant decrease was found for ADAMTS1, whose expression inversely correlated with MVD. Its role in progression of prostate cancer needs further investigation, but this inhibitor of angiogenesis could be an interesting candidate for future anti-angiogenic therapy.

quantified by counting the number of CD34-positive blood vessels. RESULTSADAMTS1 was strongly expressed in the luminal epithelial cells in benign prostate glands, whereas expression was significantly lower in prostate cancer cells. There was no obvious difference between hormone-naïve and hormone-refractory tumours, and ADAMTS1 expression did not correlate with Gleason score. However, in hormonerefractory tumours from patients with metastatic disease, the expression of ADAMTS1 was significantly lower than in tumours from patients without metastases. Furthermore, the MVD was higher in hormone-refractory than in hormone-naïve tumours and benign tissue, and MVD correlated with Gleason score. There was no association between ADAMTS1 and MVD in the hormone-naïve tumours, while hormone-refractory tumours with low ADAMTS1 expression had a higher MVD than those with moderate/high expression. CONCLUSIONADAMTS1 expression is decreased in prostate cancer, and might be involved in the early steps of prostate cancer development. Further, ADAMTS1 might have an antiangiogenic and antimetastatic role in hormone-refractory prostate cancer, where low ADAMTS1 expression is associated with a high MVD and metastasis. KEYWORDSADAMST1, angiogenesis, androgen independent, microvessel density, prostate cancer OBJECTIVETo investigate the expression of 'ADAM metallopeptidase with thrombospondin type