title: Vasoactive intestinal peptide transactivates the androgen receptor through a protein kinase A-dependent extracellular signal-regulated kinase pathway in prostate cancer LNCaP cells.
abstract: Acquisition of androgen independence by prostate cancer is the key problem of prostate cancer progression. Vasoactive intestinal peptide (VIP), a neuropeptide, may act as a survival factor for prostate cancer cells under androgen deprivation. However, the molecular mechanisms by which VIP promotes the androgen-independent growth of androgen-sensitive prostate cancer cells have not been addressed. We therefore investigated the biological effect and signal pathway of VIP in LNCaP cells, a prostate cancer cell line that requires androgens for growth. We showed that low nanomolar concentrations of VIP, acting through G(s)-protein-coupled VIP receptors, can induce LNCaP cell growth in the absence of androgen. Blockade of androgen-receptor (AR) in these cells by AR antagonist bicalutamide or by anti-AR small interfering RNA, inhibited the proliferative effect of VIP. In addition, VIP stimulated androgen-independent activation of AR with an EC(50) of 3.0 +/- 0.8 nM. We then investigated VIP-stimulated signaling events that may interact with the AR pathway in prostate cancer cells. VIP regulation of AR activation, mediated by VIP receptors, was protein kinase A (PKA)-dependent, and extracellular signal-regulated kinase 1/2 (ERK1/2) activation contributes to VIP-mediated AR activation. Furthermore, PKA-dependent Rap1 activation is required for both ERK1/2 activation and androgen-independent AR activation in LNCaP cells upon VIP stimulation. Finally, we showed that VIP-induced AR activation was also present in prostate cancer CWR22Rv1 and PC3 cells transfected with the wild-type AR. Altogether, we demonstrate that VIP acting through its G(s)-protein-coupled receptors can cause androgen-independent transactivation of AR through a PKA/Rap1/ERK1/2 pathway, thus promoting androgen-independent proliferation of androgen-sensitive prostate cancer cells.
authors: Department of Pharmacology, Creighton University School of Medicine, Omaha, NE 68178, USA.
authors: Yan
authors: Y
authors: Xie
authors: Dennis W
authors: DW
authors: Wolff
authors: Ming-Fong
authors: MF
authors: Lin
authors: Yaping
authors: Y
authors: Tu
mesh_terms: D021581:Active Transport, Cell Nucleus; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology*; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008297:Male; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D011944:Receptors, Androgen / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*; D020827:rap1 GTP-Binding Proteins / Q000502:physiology
chemical_list: D011944:Receptors, Androgen; D014660:Vasoactive Intestinal Peptide; D017868:Cyclic AMP-Dependent Protein Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D020827:rap1 GTP-Binding Proteins