Ginsenoside 20(S)-Rg3 suppresses ovarian cancer migration via hypoxia-inducible factor 1 alpha and nuclear factor-kappa B signals.

Hypoxia-inducible factor 1 is believed to play a prominent role in the survival and developing progress of cancers. As a result, inhibiting α subunit of hypoxia-inducible factor 1 represents an attractive strategy against tumor. Although hypoxia-inducible factor 1α is a hypoxia-regulated subunit, increasing evidence indicates that hypoxia-inducible factor 1α could stable expression under normoxic conditions, regulated by non-hypoxia-mediated mechanisms. However, there are few strategies to target hypoxia-inducible factor 1α under normoxic conditions. Here, we report that ginsenoside 20(S)-Rg3, one of the main active ingredients in red ginseng, restrains hypoxia-inducible factor 1α expression under normal oxygen levels in human ovarian cancer cell lines, SKOV3 and 3AO, which leads to potently inhibits migration of ovarian cancer in vitro and in vivo. 20(S)-Rg3 could decrease the expression of hypoxia-inducible factor 1α by upregulation of prolyl hydroxylase domain protein 1 to promoting hypoxia-inducible factor 1α ubiquitin-proteasome degradation under normal oxygen levels. Furthermore, 20(S)-Rg3 could attenuate the expression of nuclear factor-κ B, which may be another possible mechanism for 20(S)-Rg3 to block ovarian cancer migration. Taken together, our study suggests that 20(S)-Rg3 is a strong inhibitor of hypoxia-inducible factor 1α, which may provide a novel agent for future treatments for ovarian cancer.