Effects of bicalutamide and 4OH-tamoxifen on androgen-regulated gene expression in the LNCaP cell line.

Background: Bicalutamide (BIC) is an alternative treatment to castration for advanced prostate cancer. Breast events are common adverse effects which can be effectively prevented by the concurrent administration of tamoxifen, a selective estrogen receptor modulator. Materials and Methods: We investigated the effects of BIC, 4-hydroxy Tamoxifen (4OHT), the active metabolite of tamoxifen, and their combination on the expression of a panel of genes implicated in prostate cancer development and progression in LNCaP cells stimulated with dihydrotestosterone. Results: Our findings confirm the anti-proliferative activity of BIC on LNCaP cell growth but also show the down-regulating function of this anti-androgen on the expression of genes involved in tumor proliferation and invasion [cyclins, caspases, epidermal growth factor (EGF)]. The combination with 4OHT exerts a synergistic effect on the downregulation of some genes involved in prostate cancer progression. Conclusion: The observation that the expression of several genes [such as B-cell lymphoma-2 (BCL2), myelocytomatosis oncogene (MYC), caspases] is modulated midly-to-moderately, after 4OHT addition suggests that this combined approach in the clinical setting should be further investigated through appropriate trials.