Labda-8(17),12,14-trien-19-oic acid contained in fruits of Cupressus sempervirens suppresses benign prostatic hyperplasia in rat and in vitro human models through inhibition of androgen and STAT-3 signaling.

Fruit extract of Cupressus sempervirens (CS), which is used traditionally to treat Benign Prostatic Hyperplasia (BPH)-like urinary symptoms in patients, was scientifically validated for anti-BPH activity. The ethanolic fruit extract of CS inhibited proliferation of human BPH-stromal cells and the activity was localized to its chloroform-soluble, diterpene-rich fraction. Eight major diterpenes isolated from this fraction exhibited moderate to potent activity and the most active diterpene (labda-8(17),12,14-trien-19-oic acid) exhibited an IC50 of 37.5 µM (antiproliferative activity against human BPH-stromal cells). It significantly inhibited activation (phosphorylation) of Stat-3 in BPH-stromal cells and prevented transactivation of androgen sensitive KLK3/PSA and TMPRSS2 genes in LNCaP cells. Labda-8(17),12,14-trien-19-oic acid-rich CS fraction prevented prostatic hyperplasia in rat model and caused TUNEL labeling of stromal cells with lower expressions of IGF-I, TGF-ß and PCNA, and bcl-2/bax ratio. Human BPH tissues exhibited precise lowering of stromal component after incubation in labda-8(17),12,14-trien-19-oic acid, ex vivo. We conclude that labda-8(17),12,14-trien-19-oic acid contained in CS exhibits anti-BPH activity through inhibition of stromal proliferation and suppression of androgen action in the prostate, presenting a unique lead structure for further optimization of anti-BPH activity.

Selective estrogen receptor modulators regulate stromal proliferation in human benign prostatic hyperplasia by multiple beneficial mechanisms--action of two new agents.

The existing drugs for benign prostatic hyperplasia (BPH) are partially effective with undesirable side-effects; hence new agents acting by different mechanism(s) are required as supplements. Modulation of estrogen receptor signaling using selective estrogen receptor modulators (SERMs) offers an alternative approach for BPH management. Using human BPH-derived stromal cells and tissue explants in culture we evaluated two SERMs, DL-2-[4-(2-piperidinoethoxy)phenyl]-3-phenyl-2 H-1-benzopyran (BP) and Ormeloxifene (Orm) in comparison to Tamoxifen (Tam) and 4-hydroxytamoxifen (OHT). BP, OHT and Tam were more effective than Orm in reducing stromal cell proliferation of human BPH. BP was either equipotent or more effective than OHT and Tam in increasing estrogen receptor(ER)-ß, TGFß1, Fas and FasL, and in decreasing ER-α, AR, EGF-R and IGF-I expressions in BPH stromal cells. BP, Tam and Orm (1.0 mg/Kg) reduced rat prostate weights by almost same extent as Finasteride (Fin, 5.0 mg/Kg); however combination treatment (SERM+Fin) was more effective. BP was exceptionally efficient in reducing IGF-1 and cleaving PARP while combination treatments more effectively increased bax:bcl-2 ratio. Fin reduced acinar diameter and prostatic DHT level but increased testosterone, estradiol (E(2)) and E(2)/T+DHT ratio. SERMs, especially BP, reduced epithelial cell height drastically without significantly altering steroid hormone levels and E(2)/T+DHT ratio. Combination treatment reduced both acinar diameter and epithelial cell height with modest increase in E(2), T and E(2)/T+DHT. The study reveals the potential of SERMs per se for BPH management, and more effectively in combination with a 5α-reductase inhibitor. BP appears promising for further evaluation as a drug candidate for BPH and prostate cancer.