Botanical Formulation HX109 Ameliorates TP-Induced Benign Prostate Hyperplasia in Rat Model and Inhibits Androgen Receptor Signaling by Upregulating Ca2+/CaMKKβ and ATF3 in LNCaP Cells

Abstract

Benign prostatic hyperplasia (BPH) is a common disease in the elderly male population throughout the world. Among other factors, androgen dysregulation has been known to play major roles in its pathogenesis. HX109 is a botanical formulation prepared from a mixture of Taraxacum officinale, Cuscuta australis, and Nelumbo nucifera, which have traditionally been used—usually along with other plants—to treat urinary diseases. An ethanol extract was prepared from a mixture of these three plants, and its quality was controlled through cell-based bioassays and by quantification of several marker compounds by high-performance liquid chromatography (HPLC). In the testosterone propionate (TP)-induced prostate hyperplasia rat model, oral administration of HX109 ameliorated prostate enlargement and histological changes induced by TP. In LNCaP cells, a human prostate epithelial cell line, HX109 repressed AR-mediated cell proliferation and the induction of androgen receptor (AR) target genes at the transcriptional level without affecting the translocation or expression of AR. Such effects of HX109 on AR signaling were mediated through the control of activating transcriptional factor 3 (ATF3) expression, phosphorylation of calcium/calmodulin-dependent protein kinase kinase β (CaMKKβ), and increases in intracellular calcium, as evidenced by data from experiments involving ATF3-specific siRNA, CaMKKβ inhibitor, and calcium chelator, respectively. Taken together, our data suggest that HX109 might be used as a starting point for developing therapeutic agents for the treatment of BPH.