Two New Seco-Labdane Diterpenoids from the Leaves of Callicarpa nudiflora.

Two new seco-labdane diterpenoids, nudiflopene N (1) and nudiflopene O (2), and four known compounds were isolated from the leaves of Callicarpa nudiflora. The structures of the new compounds were established by 1D-, 2D-NMR, and HR-ESI-MS spectral analyses. Compounds 1-3 showed inhibitory activities on lipopolysaccharide-induced nitric oxide (NO) production in RAW264.7 cells, and new compounds 1-2 exhibited more potent inhibitory activity than compound 3. The cytotoxicity of compounds 1-3 against human hepatocellular carcinoma HepG2 cells and human gastric carcinoma SGC-7901 cells were evaluated, while all of them exhibited no cytotoxicity.

A new isoflavone glycoside from Abrus cantoniensis.

A new isoflavone glycoside named as 8-O-methylrelusin-7-O-ß-D-apifuranosyl-(1→2)-ß-D-glucopyranoside (1), together with two known compounds, 8-O-methylrelusin-7-O-ß-D-glucopyranoside (2) and isobiflorin (3), were isolated from Abrus cantoniensis. The structure of the new compound was elucidated on the basis of spectroscopic methods including extensive 1D NMR, 2D NMR, and HRESIMS. This is the first report of isoflavone from Abrus cantoniensis. Moreover, all isolated compounds were evaluated for their cytotoxicity against SMMC-7721 and MHCC97-H cell lines.[Formula: see text].

Two new flavonoids from Selaginella uncinata.

Two new flavonoids, uncinataflavones A (1) and B (2), along with one known compound 6-(5-carboxyl-2-methoxyphenyl)-apigenin (3), were isolated from Selaginella uncinata (Desv.) Spring. All these compounds belong to apigenin derivatives with aryl substituents at C-6 position. The structures of new compounds were elucidated on the basis of comprehensive spectroscopic analyses (UV, IR, 1D, and 2D NMR as well as HR-ESI-MS).

[A new flavonoid with an aryl moiety from Selaginella uncinata].

The present study is to investigate the chemical constituents of the whole plants of Selaginella uncinata. A new flavonoid was isolated from the 75% ethanol extract of Selaginella uncinata by column chromatographies over macroporous resin, silica gel, Sephadex LH-20 and prep-HPLC. The structure was elucidated as 8-[4-(carboxyl)phenoxy]-5,4'-dihydroxy-7-methoxyflavanone (1) and named unciflacone G.

[Flavonoids from Selaginella uncinata].

In the current study, nine flavonoids were isolated and purified from 75% ethanol extract of Selaginella uncinata (Desv.) Spring by column chromatographic techniques over macroporous resin, polyamide, silica gel, Sephadex LH-20 and pre-HPLC. On the basis of their physico-chemical properties and spectroscopic data analyses, these compounds were elucidated as cirsimarin (1), nepitrin (2), apigenin-6-C-α-L-arabinopyranosyl-8-C-ß-D-glucopyranoside (3), apigenin-6-C-ß-D-glucopyranosyl-8-C-α-L-arabinopyranoside (4), apigenin-7-O-ß-D-glucopyranoside (5), 2,3-dihydroamentoflavone (6), 4'-O-methylamentoflavone (7), 2,3-dihydro-4'-O-methyl-amentoflavone (8), and 2,3,2",3"-tetrahydron-4'-O-methyl-robustaflavone (9). Compounds 1-5 belong to flavonoid glycosides and were isolated from the genus Selaginella for the first time.

[Retracted] Induction of apoptosis by casticin in cervical cancer cells through reactive oxygen species­mediated mitochondrial signaling pathways.

Following the publication of the above paper, it was drawn to the Editors' attention by a concerned reader that certain of the lanes shown in the DNA agarose gel electrophoresis experiment in Figs. 2D bore some striking similarities; furthermore, there were unexpectedly similar­looking bands included within the gel slices for the western blotting experiments portrayed in Fig. 3B and C. The Editor of Oncology Reports independently received a request from the authors that this paper be retracted, and in view of the uncertainties regarding some of the data shown in Figs. 2 and 3, the Editor agrees with the authors' request that their paper be retracted. The Editor apologizes to the readership for any inconvenience caused. [Oncology Reports 26: 1287­1294, 2011; DOI: 10.3892/or.2011.1367].

Induction of apoptosis by casticin in cervical cancer cells: reactive oxygen species-dependent sustained activation of Jun N-terminal kinase.

Casticin, a polymethoxyflavone from Fructus viticis used as an anti-inflammatory agent in Chinese traditional medicine, has been reported to have anti-cancer activity. The purpose of this study was to examine the apoptotic activity of casticin on human cervical cancer cells and its molecular mechanism. We revealed a novel mechanism by which casticin-induced apoptosis occurs and showed for the first time that the apoptosis induced by casticin is mediated through generation of reactive oxygen species (ROS) and sustained activation of c-Jun N-terminal kinase (JNK) in HeLa cells. Casticin markedly increased the levels of intracellular ROS and induced the expression of phosphorylated JNK and c-Jun protein. Pre-treatment with N-acetylcysteine and SP600125 effectively attenuated induction of apoptosis by casticin in HeLa cells. Moreover, casticin induced ROS production and apoptotic cell death in other cervical cancer cell lines, such as CasKi and SiHa. Importantly, casticin did not cause generation of ROS or induction of apoptosis in normal human peripheral blood mononuclear cells and embryonic kidney epithelium 293 cells. These results suggest that ROS generation and sustained JNK activation by casticin play a role in casticin-induced apoptosis and raise the possibility that treatment with casticin might be promising as a new therapy against human cervical cancer.

Cytotoxic flavonoids from the leaves of Callicarpa nudiflora hook.

A new flavonoid glycoside, luteolin-3'-O-ß-D-6″-acetyl glucopyranoside (1), along with six known flavonoids, were isolated from the leaves of Callicarpa nudiflora Hook. The structures of the isolated compounds were established on the basis of extensive spectroscopic analyses. Compound 6 exhibited potent cytotoxicity and compounds 1 and 7 exhibited moderate cytotoxicity against human hepatocellular carcinoma SMMC-7721 cells.

Synergistic inhibition of characteristics of liver cancer stem-like cells with a combination of sorafenib and 8-bromo-7-methoxychrysin in SMMC-7721 cell line.

Sorafenib, a multi-kinase inhibitor, has shown its promising antitumor effect in a series of clinical trials, and has been approved as the current standard treatment for advanced hepatocellular carcinoma (HCC). 8-Bromo­7-methoxychrysin (BrMC) is a novel chrysin synthetic analogue that has been reported to inhibit the growth of various tumor cells and possess properties for targeting liver cancer stem cells (LCSCs) . The present study investigated the synergistic targeting effects on the properties of liver cancer stem-like cells (LCSLCs) by a combination of sorafenib and BrMC in SMMC-7721 cell line. We also investigated whether this effect involves regulation of HIF-1α, Twist and NF-κB protein. We found that the sphere-forming cells (SFCs) from the SMMC­7721 cells possessed the properties of LCSLCs. Sorafenib diminished the self-renewal capacity and downregulated the expression of stem cell biomarkers (CD133, CD44 and ALDH1) in a dose-dependent manner, while BrMC cooperated with sorafenib to strengthen this inhibition. Moreover, the combination of sorafenib and BrMC led to a remarkable decrease in the cellular migration and invasion, the downregulation of N-cadherin protein and upregulation of E-cadherin protein, and increase of cell apoptosis in LCSLCs. BrMC has a remarkable antagonistic effect on the upregulation of protein expression and DNA binding activity of NF-κB (p65) induced by sorafenib. In addition, our results indicated that the synergistic inhibition of sorafenib and BrMC on the characteristics of LCSLCs involves the downregulated expression of HIF-1α and EMT regulator Twist1. Collectively, the combination therapy of sorafenib and BrMC could be a new and promising therapeutic approach in the treatment of HCC.

Casticin inhibits self-renewal of liver cancer stem cells from the MHCC97 cell line.

Casticin exerts anticarcinogenic activity in several types of cancers, including human hepatocellular carcinoma (HCC). The aim of the present study was to investigate the effects of casticin, which is derived from Fructus Viticis Simplicifoliae, on the self-renewal capacity of liver cancer stem cells (LCSCs) derived from the HCC MHCC97 cell line. The present study demonstrated that casticin significantly inhibited the proliferation of LCSCs from the MHCC97 cell line in a dose-dependent manner (P<0.05), the half maximal inhibitory concentration of the parental cells and LCSCs was 17.9 and 0.5 µmol/l, respectively. Furthermore, casticin reduced the sphere-forming capacity of LCSCs and downregulated ß-catenin protein expression in a concentration-dependent manner. Lithium chloride, an agonist known to activate the Wnt/ß-catenin signaling pathway, attenuated the casticin-induced downregulation of ß-catenin protein expression and inhibited the self-renewal capacity. To the best of our knowledge, the present study is the first to demonstrate that casticin effectively eradicates LCSCs and ß-catenin was identified as the potential target. Thus, casticin may offer a novel therapeutic approach for the treatment of HCC.

Casticin inhibits epithelial-mesenchymal transition of liver cancer stem cells of the SMMC-7721 cell line through downregulating Twist.

The existence of cancer stem cells (CSCs) is central to the pathogenesis and therapeutic target of human hepatocellular carcinoma. The aim of this study was to investigate the effects of casticin on epithelial-mesenchymal transition (EMT) of liver cancer stem cells (LCSCs) derived from the SMMC-7721 cell line. Our results demonstrated that CD133+ sphere-forming cells (SFCs) sorted from the SMMC-7721 cell line not only possessed a higher capacity to form tumor spheroids in vitro, but also had a greater potential to form tumors when implanted in Balb/c-nu mice, indicating that CD133+ SFCs possessed similar traits to LCSCs. Casticin increased the expression levels of E-cadherin and decreased those of N-cadherin in LCSCs. Treatment of LCSCs with casticin for 48 h also decreased the levels of the EMT-associated transcription factor, Twist. Overexpression of Twist attenuated the casticin-induced regulation of E-cadherin and N-cadherin protein expression, as well as the EMT capacity of LCSCs. In conclusion, CD133+ SFCs of the SMMC-7721 cell line may represent a subpopulation of LCSCs with the characteristics of EMT. Furthermore, casticin targeted LCSCs through the inhibition of EMT by downregulating Twist.

Casticin induces breast cancer cell apoptosis by inhibiting the expression of forkhead box protein M1.

Casticin is an active ingredient derived from Fructus Viticis, a traditional Chinese medicine. This study aimed to investigate the role of forkhead box O3 (FOXO3a) in breast cancer cells and examine the regulatory mechanisms of FOXO3a in response to casticin treatment of the cells by ELISA, flow cytometry, small interfering RNA (siRNA) transfection and western blot analysis. Casticin treatment induced apoptosis and reduced the expression of the transcription factor forkhead box protein M1 (FOXM1). In addition, FOXM1 repression induced by casticin treatment was associated with the activation of FOXO3a via increased dephosphorylation. Notably, silencing FOXO3a expression by siRNA-mediated gene knockdown attenuated casticin-mediated apoptosis. Collectively, these findings suggest that FOXO3a is a critical mediator of the inhibitory effects of casticin on apoptosis in breast cancer cells.

Casticin induces ovarian cancer cell apoptosis by repressing FoxM1 through the activation of FOXO3a.

Casticin, a polymethoxyflavone, is reported to have anticancer activities. The aim of the present study was to examine the molecular mechanisms by which casticin induces apoptosis in ovarian cancer cells. The human ovarian cancer cell lines SKOV3 and A2780 were cultured in vitro. Various molecular techniques, including histone/DNA enzyme-linked immunosorbent assay (ELISA), reverse transcription polymerase chain reaction (RT-PCR), western blot analysis and gene transfection, were used to assess the expression of FOXO3a and forkhead box protein M1 (FoxM1) in casticin-treated ovarian cancer cell lines. Casticin-induced apoptotic cell death was accompanied by the activation of transcription factor FOXO3a, with a concomitant decrease in the expression levels of FoxM1 and its downstream target factors, namely survivin and polo-like kinase 1 (PLK1), and an increase in p27KIP1. A small inhibitory RNA (siRNA) knockout of FoxM1 potentiated casticin-induced apoptosis in ovarian cancer cells. Silencing FOXO3a expression using siRNA increased FoxM1 expression levels and clearly attenuated the induction of apoptosis by casticin treatment. These results show that casticin-induced apoptosis in ovarian cancer may be caused by the activation of FOXO3a, leading to FoxM1 inhibition.

Induction of apoptosis by casticin in cervical cancer cells through reactive oxygen species-mediated mitochondrial signaling pathways.

Casticin, one of the main components from Fructus Viticis, has been reported to inhibit the growth of various cancer cells, including the human cervical cancer cell line HeLa. The purpose of this study was to examine the apoptotic activity and molecular mechanism of casticin action on human cervical cancer cells. The apoptotic activity of casticin on human cervical cancer HeLa, CasKi, SiHa and peripheral blood mononuclear cells (PBMCs) was measured using a histone/DNA ELISA assay, flow cytometry with propidium iodide (PI) staining and DNA agarose gel electrophoresis. The mitochondrial membrane potential and reactive oxygen species (ROS) production were evaluated by flow cytometry analysis. Caspase activities were assayed using a caspase colorimetric activity assay kit. Protein expression levels of cytochrome c, Bax, Bcl-2, Bcl-xL and XIAP were analyzed by Western blotting. Casticin caused accumulation of the Sub-G1 cells and increased reactive oxygen species (ROS) production in HeLa, CasKi, SiHa cell lines, but not in PBMCs. Apoptosis of HeLa cells was induced by casticin via mitochondrial release of cytochrome c due to the reduction of mitochondrial trans-membrane potential, activation of caspase-3 and -9, and the production of reactive oxygen species. The pan caspase inhibitor zVAD-FMK, the caspase-9 inhibitor zLEHD-fmk and N-acetylcysteine suppressed casticin-induced apoptosis. Bax was upregulated, while expression levels of Bcl-xL and XIAP were downregulated. However, there was no change in the expression of Bcl-2 under the same treatment. Our results indicate that casticin-induced apoptosis of cervical cancer cells is mediated by ROS generation and mitochondrial signaling pathways.

Casticin-induced apoptosis involves death receptor 5 upregulation in hepatocellular carcinoma cells.

AIM: To investigate the apoptotic activities of casticin in hepatocellular carcinoma (HCC) cells and its molecular mechanisms. METHODS: PLC/PRF/5 and Hep G2 cell lines were cultured in vitro and the inhibitory effect of casticin on the growth of cells was detected by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolim bromide (MTT) assay. The apoptotic cell death was examined using the cell apoptosis enzyme linked immunosorbent assay (ELISA) detection kit, flow cytometry (FCM) after propidium iodide (PI) staining and DNA agarose gel electrophoresis. The caspase activities were measured using ELISA. Reactive oxygen species (ROS) production was evaluated by FCM after dichlorodihydrofluorescein diacetate (DCFH-DA) probe labeling. Intracellular glutathione (GSH) content was measured using a glutathione assay kit. The expression of death receptor (DR)4 and DR5 proteins was analyzed by Western blotting and FCM. RESULTS: Casticin significantly inhibited the growth of human HCC (PLC/PRF/5 and Hep G2) cells in a dose-dependent manner (P < 0.05). Casticin increased the percentage of the sub-G1 population in HCC cells in a concentration-dependent manner. The potency of casticin to PLC/PRF/5 cells was higher than that of 5-flurouracil (26.8% ± 4.8% vs 17.4% ± 5.1%) at 10 µmol/L for 24 h. Casticin increased the levels of Histone/DNA fragmentation and the levels of active caspase-3, -8 and -9 in a concentration-dependent manner (P < 0.05). Treatment with 30 µmol/L casticin for 24 h resulted in the formation of a DNA ladder. Casticin reduced the GSH content (P < 0.05), but did not affect the level of intracellular ROS in PLC/PRF/5 and Hep G2 cells. The thiol antioxidants, acetylcysteine (NAC) and GSH restored GSH content and attenuated casticin-induced apoptosis. In contrast, the nonthiol antioxidants, butylated hydroxyanisole and mannitol failed to do so. In the HCC cells treated with casticin for 24 h, DR5 protein level was increased. The expression of DR5 protein induced by casticin was inhibited by NAC. Pretreatment with DR5/Fc chimera protein, a blocking antibody, effectively attenuated the induction of apoptosis by casticin. CONCLUSION: Casticin-induced apoptosis of HCC cells is involved in GSH depletion and DR5 upregulation.