20(S)-ginsenoside Rg3 induced the necroptosis of prostate cancer cells via ROS overproduction.

Necroptosis is a programmed form of necrosis and compounds inducing necroptosis may contribute to cancer treatment. 20(S)-ginsenoside Rg3 is a natural compound extracted from ginseng, which exhibited a broad-spectrum of antitumor activity. In the present study, the potential role of 20(S)-ginsenoside Rg3 in inducing necroptosis in prostate cancer cells was evaluated. 20(S)-ginsenoside Rg3 inhibited the proliferation of prostate cancer cells and upregulated the expression of necroptotic proteins such as receptor-interacting serine/threonine-protein kinase 1 (RIPK1), RIPK3, and their downstream mixed lineage kinase domain-like protein (MLKL). Pretreatment with the selective RIPK1 inhibitor necrostatin-1 (Nec-1) partially reversed the inhibitory effect of 20(S)-ginsenoside Rg3 on prostate cancer cell proliferation. 20(S)-ginsenoside Rg3 led to the accumulation of reactive oxygen species (ROS) and the regulation of autophagy in cancer cells. Scavenging ROS with N-acetyl-L-cysteine (NAC) antagonized the regulatory effects of 20(S)-ginsenoside Rg3 on cell autophagy and necroptotic proteins expression. Moreover, 20(S)-ginsenoside Rg3 exhibited an antitumor effect in a prostate cancer xenograft mouse model in which it upregulated the expression of RIPK1, RIPK3, MLKL and led to a decrease in tumor weight, as well as an increase in necrotic areas in tumor tissue. In conclusion, our study showed that 20(S)-ginsenoside Rg3 might induce necroptosis in prostate cancer in vitro and in vivo via the ROS/autophagy signaling pathway.