Wnt-11 promotes neuroendocrine-like differentiation, survival and migration of prostate cancer cells

Wnt-11 protein levels in prostate tumours were determined by immunohistochemical analysis of prostate tumour tissue arrays. Wnt-11 protein was elevated in 77/117 of tumours when compared with 27 benign prostatic hypertrophy specimens and was present in 4/4 bone metastases. In addition, there was a positive correlation between Wnt-11 expression and PSA levels above 10 ng/ml. Androgen-depleted LNCaP prostate cancer cells form neurites and express genes associated with neuroendocrine-like differentiation (NED), a feature of prostate tumours that have a poor prognosis. Since androgen-depletion increases expression of Wnt-11, we examined the role of Wnt-11 in NED. Ectopic expression of Wnt-11 induced expression of NSE and ASCL1, which are markers of NED, and this was prevented by inhibitors of cyclic AMP-dependent protein kinase, consistent with the known role of this kinase in NED. In contrast, Wnt-11 did not induce NSE expression in RWPE-1 cells, which are derived from benign prostate, suggesting that the role of Wnt-11 in NED is specific to prostate cancer. In addition, silencing of Wnt-11 expression in androgen-depleted LNCaP cells prevented NED and resulted in apoptosis. Silencing of Wnt-11 gene expression in androgen-independent PC3 cells also reduced expression of NSE and increased apoptosis. Finally, silencing of Wnt-11 reduced PC3 cell migration and ectopic expression of Wnt-11 promoted LNCaP cell invasion.These observations suggest that the increased level of Wnt-11 found in prostate cancer contributes to tumour progression by promoting NED, tumour cell survival and cell migration/invasion, and may provide an opportunity for novel therapy in prostate cancer.Wnt genes code for secreted signalling proteins that are responsible for the development and repair of many organs in the body and aberrant activation of Wnt signalling is implicated in tumorigenesis [1]. We have previously reported increased expression of Wnt-11 mRNA in androgen-independent prostate cancer