Regulation of prostate-specific membrane antigen (PSMA) expression in prostate cancer cells after treatment with dutasteride and lovastatin.

PSMA expression gradually increases from benign prostatic hyperplasia to adenocarcinoma of the prostate and is therefore used for the development of improved diagnostic (PSMA)-based prostate cancer imaging tools. Pharmacological induction of PSMA is therefore eminent to further improve the detection rate of PSMA-based imaging. Our previous studies have demonstrated that lovastatin (Lova) and dutasteride (Duta) are able to induce PSMA expression. However, the mechanisms by which PSMA is regulated in prostate cancer remain poorly understood. Androgen receptor (AR) and homeobox B13 (HOXB13) are the best known regulators of PSMA, hence in the present study we aimed to explore the PSMA regulation by HOXB13 and AR signaling in LNCaP and VCaP cells following treatments with Lova and Duta. Furthermore, our previous research revealed a growth arrest in prostate cancer cells after Lova, but not after Duta treatment. To understand this discrepancy, we explored the influence of Lova and Duta on well known tumor growth promoters, such as AR, the mTOR/Akt signaling pathways and Cyclin D1. Our results showed that treatment with Lova leads to a significant inhibition of the investigated tumor promoters and results in growth regression of LNCaP and VCaP cells. In contrast, Duta does not show these effects. Furthermore, we confirm the cooperative effect of HOXB13 and AR in regulating PSMA in LNCaP cells, and extend the investigations to an additional prostate cancer cell line (VCaP).