Wogonin and fisetin induction of apoptosis through activation of caspase 3 cascade and alternative expression of p21 protein in hepatocellular carcinoma cells SK-HEP-1

Abstract

Wogonin and fisetin are flavonoids, which are widely distributed in plants. Our recent study demonstrated that, among seven structurally related flavonoids, wogonin and fisetin showed the most potent apoptosis-inducing activities in human promyeloleukemic cells HL-60. In the present investigation, we performed molecular studies to assess the apoptotic effects of wogonin and fisetin on hepatocellular carcinoma cells SK-HEP-1. Both wogonin and fisetin showed dose-dependent cytotoxic effects on SK-HEP-1 cells, accompanied by DNA fragmentation. Microscopic observation under Giemsa staining showed that wogonin and fisetin, at the dose of 80 microM, induced cellular swelling and the appearance of apoptotic bodies, characteristics of apoptosis, in SK-HEP-1 cells. Furthermore, flow cytometry analysis showed an increase of hypodiploid cells in wogonin- and fisetin-treated SK-HEP-1 cells. These data demonstrated that wogonin and fisetin were effective inducers of apoptosis in SK-HEP-1 cells. Treatment with an apoptosis-inducing concentration of wogonin or fisetin caused induction of caspase 3/CPP32 activity, but not of caspase 1 activity. In addition, a caspase 3 inhibitor, Ac-DEVD-CHO, but not the caspase 1 inhibitor Ac-YVAD-CHO, reversed the cytotoxic effects of wogonin and fisetin on SK-HEP-1 cells. Further, cleavage of caspase 3 substrates including poly(ADP-ribose) polymerase (PARP) and D4-GDI protein, and decrease of pro-caspase 3 protein were detected in wogonin- and fisetin-treated SK-HEP-1 cells. Increase of p53 protein was associated with wogonin- and fisetin-induced apoptosis; however, a p53-controlled gene, p21(Waf/Cip-1), was only induced in wogonin- (not fisetin-) treated SK-HEP-1 cells. Serum starvation elevated p21(Waf/Cip-1) protein expression, and enhanced the apoptotic induction activity of wogonin (not fiseitn) in SK-HEP-1 cells. Our study has provided molecular evidence to demonstrate that wogonin and fisetin had effective cytotoxic effects through apoptosis induction in hepatocellular carcinoma cells SK-HEP-1; activation of caspase 3 cascade, induction of p53 protein and alternative expression of p21(Waf/Cip-1) protein were involved.

Novel antiproliferative flavonoids induce cell cycle arrest in human prostate cancer cell lines

“…Flavonoids have been shown to alter a number of key proteins implicated in growth and differentiation. These include induction of cyclin-dependent kinase (cdk) inhibitors p21 Cip1/WAF1 and p27 Kip1 , 39,42 inhibition of phosphorylation of retinoblastoma (Rb) protein, 43 decrease in levels of cyclins B, D and E and cdk 2,4 and 6, 44-46 induction of apoptosis, 47,48 inhibition of topoisomerase II, and alterations to the MAPkinase pathway. 49 Genestein, a soy isoflavone, enhances the antiproliferative effects of vitamin D by upregulating vitamin D receptor and p21 Cip1/WAF1 protein levels.…”

High-yield production of scutellaria radix flavonoids (baicalein, baicalin and wogonin) by liquid-culture of Scutellaria baicalensis root-derived cells

“…The inhibitory effects of baicalein and baicalin on expansion of human viruses (Bayer et al, 1992;Wu et al, 1995), and a protective effect of baicalin on renal cell injury (Yokozawa et al, 1999) have been reported. It was also reported that baicalein, baicalin and wogonin showed suppression activity against the production of nitric oxide/prostaglandin E 2 (Chen et al, 2001;Chi et al, 2001) and proliferation of cancer cells (Chan et al, 2000;Chen et al, 2002;Matsuzaki et al, 1996;Okita et al, 1993;Yano et al, 1994).…”

Fisetin inhibits the growth and migration in the A549 human lung cancer cell line via the ERK1/2 pathway

“…At present, fisetin has shown multiple biological activities including anti-proliferative (7,8), pro-apoptotic (9-13), neuroprotective (14) and anti-oxidative activities (15). Moreover, fisetin has been shown to suppress the proliferation of a wide variety of tumor cell, including prostate cancer (16), liver cancer (17), colon cancer (18) and leukemia (19) cells, and inhibit the mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB signaling pathways in various type of cancer cell, such as colon and pancreatic cancer (14,(20)(21)(22)(23)(24). Fisetin was also reported to reduce the invasive and migratory capacity of the A549 human lung cancer cell line via the extracellular signal-regulated kinase (ERK) signaling pathway (25).…”