Selective Androgen Receptor Modulator, YK11, Up-Regulates Osteoblastic Proliferation and Differentiation in MC3T3-E1 Cells

Androgens are key regulators that play a critical role in the male reproductive system and have anabolic effects on bone mineral density and skeletal muscle mass. We have previously reported that YK11 is a novel selective androgen receptor modulator (SARM) and induces myogenic differentiation and selective gene regulation. In this study, we show that treatment of YK11 and dihydrotestosterone (DHT) accelerated cell proliferation and mineralization in MC3T3-E1 mouse osteoblast cells. Further, YK11-treated cells increased osteoblast specific differentiation markers, such as osteoprotegerin and osteocalcin, compared to untreated cells. These observations were attenuated by androgen receptor (AR) antagonist treatment. To clarify the effect of YK11, we investigated rapid non-genomic signaling by AR. The phosphorylated Akt protein level was increased by YK11 and DHT treatment, suggesting that YK11 activates Akt-signaling via non-genomic signaling of AR. Because it is known Akt-signaling is a key regulator of androgen-mediated osteoblast differentiation, YK11 has osteogenic activity as well as androgen.