Compound K, a metabolite of ginseng saponin, induces apoptosis via caspase-8-dependent pathway in HL-60 human leukemia cells

Abstract

BackgroundCompound K [20-O-β-(D-glucopyranosyl)-20(S)-protopanaxadiol], a metabolite of the protopanaxadiol-type saponins of Panax ginseng C.A. Meyer, has been reported to possess anti-tumor properties to inhibit angiogenesis and to induce tumor apoptosis. In the present study, we investigated the effect of Compound K on apoptosis and explored the underlying mechanisms involved in HL-60 human leukemia cells.MethodsWe examined the effect of Compound K on the viabilities of various cancer cell lines using MTT assays. DAPI assay, Annexin V and PI double staining, Western blot assay and immunoprecipitation were used to determine the effect of Compound K on the induction of apoptosis.ResultsCompound K was found to inhibit the viability of HL-60 cells in a dose- and time-dependent manner with an IC50 of 14 μM. Moreover, this cell death had typical features of apoptosis, that is, DNA fragmentation, DNA ladder formation, and the externalization of Annexin V targeted phosphatidylserine residues in HL-60 cells. In addition, compound-K induced a series of intracellular events associated with both the mitochondrial- and death receptor-dependent apoptotic pathways, namely, (1) the activation of caspases-3, -8, and -9; (2) the loss of mitochondrial membrane potential; (3) the release of cytochrome c and Smac/DIABLO to the cytosol; (4) the translocation of Bid and Bax to mitochondria; and (5) the downregulations of Bcl-2 and Bcl-xL. Furthermore, a caspase-8 inhibitor completely abolished caspase-3 activation, Bid cleavage, and subsequent DNA fragmentation by Compound K. Interestingly, the activation of caspase-3 and -8 and DNA fragmentation were significantly prevented in the presence of cycloheximide, suggesting that Compound K-induced apoptosis is dependent on de novo protein synthesis.ConclusionsThe results indicate that caspase-8 plays a key role in Compound K-stimulated apoptosis via the activation of caspase-3 directly or indirectly through Bid cleavage, cytochrome c release, and caspase-9 activation.

Effects of the Ethylacetate Extract of <i>Orostachys japonicus</i> on Induction of Apoptosis through the p53-Mediated Signaling Pathway in Human Gastric Cancer Cells

“…As one of the primary pathways of apoptosis, a mitochondria pathway, which is controlled through the bcl-2 family of proteins, is activated, and is finalized when caspase-3, a final executing factor, and DNase is activated, resulting in apoptosis by DNA fragmentation and the formation of apoptotic bodies. 23) In this study, we found that inactive caspase-3 protein decreased in a time-dependent manner in cells treated with the EtOAc fraction, while active caspase-3 protein increased in a time-dependent manner. Also, the expression of active caspase-3 protein was significantly abrogated in the presence of the pan-caspase inhibitor Z-VAD-FMK, indicating the EtOAc fraction induces apoptosis of AGS cells by a caspase-3 dependent mechanism.…”

Ginsenoside compound K suppresses the abnormal activation of T lymphocytes in mice with collagen-induced arthritis

“…Ginsenosides, the major components of ginseng, exhibit various biological activities, including anti-inflammatory, anti-dementia, and anti-tumor effects [17][18][19] . The protopanaxadiol ginsenosides Rb1, Rb2, and Rc are metabolized to compound K (C-K; Figure 1) by intestinal bacteria in humans and rats [20][21][22] . C-K (20-O-β-D-glucopyranosyl-20(S)-protopanaxadiol) exhibits various immunopharmacological properties, including antiallergic and anti-carcinogenic effects [23][24][25] .…”

Ginsenoside Rg3 inhibits colorectal tumor growth through the down-regulation of Wnt/ß-catenin signaling

“…The major active components of ginseng are ginsenosides (such as Rg3, Rh2, Rg5, Rk1 and Rp1), a diverse group of steroidal saponins (12,13). Although the anti-tumor activities of ginseng were initially attributed to its immunomodulation activities (12), it has been reported that ginseng or ginsenosides may exhibit direct anti-cancer properties (14)(15)(16)(17)(18). Several ginsenosides (e.g., Rh2, Rg3, and Rk1) exhibit anti-proliferative and antiangiogenic activities in vitro and in vivo (19)(20)(21).…”