Ophiopogonin D' induces RIPK1‑dependent necroptosis in androgen‑dependent LNCaP prostate cancer cells.

Ophiopogonin D' (OPD') is a natural compound extracted from Ophiopogon japonicus, which is a plant used in traditional Chinese medicine. Our previous study has indicated that OPD' exhibits antitumor activity against androgen‑independent prostate cancer (PCa), but the effects and the underlying molecular mechanism of action of OPD' in androgen‑dependent PCa were unclear. In the present study, OPD' induced significant necroptosis in androgen‑dependent LNCaP cancer cells by activating receptor‑interacting serine/threonine‑protein kinase 1 (RIPK1). Exposure to OPD' also increased Fas ligand (FasL)‑dependent RIPK1 protein expression. The OPD'‑induced necroptosis was inhibited by a RIPK1 inhibitor necrostatin‑1, further supporting a role for RIPK1 in the effects of OPD´. The antitumor effects of OPD' were also inhibited by a mixed lineage kinase domain‑like protein (MLKL) inhibitor necrosulfonamide. Following treatment with inhibitors of RIPK1 and MLKL, the effects of OPD' on LNCaP cells were inhibited in an additive manner. In addition, co‑immunoprecipitation assays demonstrated that OPD' induced RIPK3 upregulation, leading to the assembly of a RIPK3‑MLKL complex, which was independent of RIPK1. Furthermore, OPD' increased the expression of Fas‑associated death domain, which is required to induce necroptosis in LNCaP cells. OPD' also regulated the expression levels of FasL, androgen receptor and prostate‑specific antigen in a RIPK1‑dependent manner. These results suggested that OPD' may exhibit potential as an anti‑PCa agent by inducing RIPK1‑ and MLKL‑dependent necroptosis.