Sensitization of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-resistant primary prostate cancer cells by isoegomaketone from Perilla frutescens.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is currently in clinical trials as a cancer treatment due to its ability to induce apoptosis selectively in cancer cells. Nevertheless, the risk of developing resistance warrants the development of sensitizers that can overcome resistance to TRAIL. In this study, isoegomaketone (1) acted as a synergistic TRAIL sensitizer by mediating up-regulation of DR5 expression in primary prostate cancer RC-58T/h/SA#4 cells. Combined with 1, TRAIL exhibited enhanced apoptotic activity in a human prostate cancer cell line designated RC-58T/h/SA#4, as indicated by increases in annexin V-positive and sub-G1 cell populations as well as condensation of chromatin or apoptotic bodies. Combined treatment also activated caspases-8, -9, and -3; increased the protein levels of Bax, AIF, and cytosolic cytochrome c; and induced PARP cleavage while reducing Bcl-2 protein expression. Human recombinant DR5 Fc chimera efficiently attenuated 1-induced apoptosis, thereby demonstrating the critical role of DR5 in 1-mediated apoptotic cell death. Furthermore, DR5 expression induced by 1 was mediated via a ROS-independent pathway that required CHOP and p53. Overall, these findings provide evidence that 1 potentiates TRAIL-mediated apoptosis through up-regulation of DR5 via a ROS-independent pathway. This suggests that 1 has potential for increasing the effectiveness of prostate cancer therapy with TRAIL.

3-deoxysilybin exerts anti-inflammatory effects by suppressing NF-κB activation in lipopolysaccharide-stimulated RAW264.7 macrophages.

3-deoxysilybin (3-DS), also known as (-)-isosilandrin A, is a natural flavonoid of Silybum marianum. This study was designed to investigate the anti-inflammatory effect and the underlying molecular mechanisms of 3-DS in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. 3-DS dose-dependently inhibited the production of NO and the expression of iNOS in LPS-stimulated RAW264.7 macrophages. 3-DS also inhibited the production of pro-inflammatory cytokines (MCP-1, TNF-α, IL-6, and IL-1ß) in LPS-stimulated RAW264.7 macrophages. Moreover, 3-DS decreased the NF-κB DNA binding activity in LPS-stimulated RAW264.7 macrophages. Furthermore, 3-DS suppressed NF-κB activation by inhibiting the degradation of IκBα and nuclear translocation of p65 subunit of NF-κB in LPS-stimulated RAW264.7 macrophages. Taken together, the present study suggests for the first time that 3-DS may exhibit an anti-inflammatory effect through the suppression of NF-κB transcriptional activation in LPS-stimulated RAW264.7 macrophages.

Isoegomaketone induces apoptosis in SK-MEL-2 human melanoma cells through mitochondrial apoptotic pathway via activating the PI3K/Akt pathway.

Isoegomaketone (IK) is a major biologically active component of Perilla frutescens. In this study, we investigated the contribution of reactive oxygen species (ROS) to IK-induced apoptosis in human melanoma SK-MEL-2 cells. We found that IK inhibited the proliferation of SK-MEL-2 human melanoma cells in a dose-dependent manner. IK also induced sub-G1 DNA accumulation, formation of apoptotic bodies, nuclear condensation, and a DNA ladder in SK-MEL-2 cells. IK also induced activation of caspase-3 and -9, whereas caspase­8 was unaffected. Further, N-acetyl-L-cysteine (NAC, ROS scavenger) treatment to SK-MEL-2 cells significantly reduced IK-induced cell death. Pretreatment of NAC to SK-MEL-2 cells followed by 100 µM IK reduced the protein levels of Bax and cytochrome c as well as PARP cleavage, whereas the protein level of Bcl-2 increased. Moreover, IK inhibited the phosphorylation of AKT/mTOR protein and cell proliferation induced by LY294002, a PI3K inhibitor. In conclusion, IK-induced ROS generation regulates cell growth inhibition and it induces apoptosis through caspase­dependent and -independent pathways via modulation of PI3K/AKT signaling in SK-MEL-2 cells.

Anti-Inflammatory Effect of Mangostenone F in Lipopolysaccharide-Stimulated RAW264.7 Macrophages by Suppressing NF-κB and MAPK Activation.

Mangostenone F (MF) is a natural xanthone isolated from Garcinia mangostana. However, little is known about the biological activities of MF. This study was designed to investigate the anti-inflammatory effect and underlying molecular mechanisms of MF in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. MF dose-dependently inhibited the production of NO, iNOS, and pro-inflammatory cytokines (TNF-α, IL-6, and IL-1ß) in LPS-stimulated RAW264.7 macrophages. Moreover, MF decreased the NF-κB luciferase activity and NF-κB DNA binding capacity in LPS-stimulated RAW264.7 macrophages. Furthermore, MF suppressed the NF-κB activation by inhibiting the degradation of IκBα and nuclear translocation of p65 subunit of NF-κB. In addition, MF attenuated the AP-1 luciferase activity and phosphorylation of ERK, JNK, and p38 MAP kinases. Taken together, these results suggest that the anti-inflammatory effect of MF is associated with the suppression of NO production and iNOS expression through the down-regulation of NF-κB activation and MAPK signaling pathway in LPS-stimulated RAW264.7 macrophages.

Induction of apoptosis by 2,3-dehydrosilybin via a caspase-dependent pathway in human HeLa cells.

The aim of this study was to investigate the mechanisms involved in the apoptosis of HeLa cells due to 2,3-dehydrosilybin (DHS) treatment. DHS treatment over 24 h significantly inhibited cell viability and induced apoptosis in a dose-dependent manner. It also triggered the cleavage of caspase-8, caspase-9, caspase-3, and PARP, and significantly increased caspase-3 activity in a dose-dependent manner. Moreover, it triggered the depolarization of the mitochondrial membrane potential (Δψm), the release of cytochrome c into the cytosol, the cleavage of Bid, and the downregulation of Bcl-2 in a dose-dependent manner. Furthermore, z-VAD-fmk (a pan-caspase inhibitor) and z-IETD-fmk (a specific caspase-8 inhibitor) abolished the DHS-induced activation of the caspase-8, -9, and -3, cleavage of PARP, the depolarization of Δψm, the release of cytochrome c, the cleavage of Bid, and the downregulation of Bcl-2. Taken together, these results suggest that DHS-induced apoptosis is mediated by a caspase-dependent pathway in human HeLa cells.

The effects of chronic gamma irradiation on oxidative stress response and the expression of anthocyanin biosynthesis-related genes in wheat (Triticum aestivum).

PURPOSE: To investigate the mechanisms of adaptation and tolerance to ionizing radiation using chronic radiation in wheat. MATERIALS AND METHODS: We exposed wheat plants to chronic gamma irradiation (50 Gy) for 2, 4, and 6 weeks and measured various biological parameters. RESULTS: Plant height was reduced by exposure to gamma irradiation; this effect increased with increasing exposure time. Photosynthetic pigment levels decreased with increasing exposure time, while anthocyanin levels significantly increased after exposure to gamma rays. The activities of antioxidant enzymes (superoxide dismutase [SOD], ascorbate peroxidase [APX], catalase [CAT], and peroxidase [POD]) and malondialdehyde (MDA) levels increased with increasing duration of exposure to gamma irradiation. Electron spin resonance (ESR) signals were strongly detected in wheat that was gamma-irradiated for two weeks and then gradually decreased with increasing exposure time. The expression of anthocyanin biosynthesis genes (flavanone 3-hydroxylase [F3H], dihydroflavonol reductase [DFR], anthocyanin reductase [ANS], and UDPG-flavonoid glucosyl transferase [UFGT]) and sugar contents increased after exposure to gamma rays. CONCLUSIONS: This suggests that exposure to ionizing radiation according to increase of exposure time has led to efficient induction of anthocyanin and antioxidant enzyme activities. This study indicates that reactive oxygen species (ROS) is eliminated by biosynthesis of anthocyanin and antioxidant enzymes. This study helps elucidate the biological effects of various durations of low-dose exposure to chronic gamma radiation in wheat plants.

Induction of apoptosis by isoegomaketone from Perilla frutescens L. in B16 melanoma cells is mediated through ROS generation and mitochondrial-dependent, -independent pathway.

We have demonstrated for the first time the mechanism underlying ROS-mediated mitochondria-dependent apoptotic cell death triggered by isoegomaketone (IK) treatment in melanoma cells. We showed that IK induced apoptotic cell death and tumor growth inhibition using tissue culture and in vivo models of B16 melanoma. Furthermore, we observed that IK effectively induced apoptotic cell death, including sub-G1 contents up-regulation, nuclei condensation, DNA fragmentation, and caspase activation in B16 melanoma cells. Pretreatment with caspase inhibitor increased the survival rate of IK-treated B16 cells, implying that caspases play a role in IK-induced apoptosis. Furthermore, IK treatment generated ROS in melanoma cells. We also determined whether or not IK-induced cell death is due to ROS production in B16 cells. N-acetyl cysteine (NAC) inhibitedIK-induced Bcl-2 family-mediated apoptosis. This result indicates that IK-induced apoptosis involves ROS generation as well as up-regulation of Bax and Bcl-2 expression, leading to release of cytochrome c and AIF. Our data suggest that IK inhibits growth and induces apoptosis in melanoma cells via activation of ROS-mediated caspase-dependent and -independent pathways.

The improvement of ginsenoside accumulation in Panax ginseng as a result of γ-irradiation.

In this study, gamma rays were used to irradiate embryogenic calli induced from cotyledon explants of Panax ginseng Meyer. After the embryogenic calli were irradiated, they were transferred to adventitious roots using an induction medium; next, mutated adventitious root (MAR) lines with a high frequency of adventitious root formations were selected. Two MAR lines (MAR 5-2 and MAR 5-9) from the calli treated with 50 Gy of gamma rays were cultured on an NH4NO3-free Murashige and Skoog medium with indole-3-butyric acid 3 mg/L. The expression of genes related to ginsenoside biosynthesis was analyzed using reverse transcription polymerase chain reaction with RNA prepared from native ginseng (NG), non-irradiated adventitious root (NAR) and 2 MAR lines. The expression of the squalene epoxidase and dammarenediol synthase genes was increased in the MAR 5-2 line, whereas the phytosterol synthase was increased in the MAR 5-9 line. The content and pattern of major ginsenosides (Rb1, Rb2, Rc, Rd, Re, Rf, and Rg1) were analyzed in the NG, NAR, and 2 MAR lines (MAR 5-2 and MAR 5-9) using TLC and HPLC. In the TLC analysis, the ginsenoside patterns in the NG, NAR, and 2 MAR lines were similar; in contrast, the MAR 5-9 line showed strong bands of primary ginsenosides. In the HPLC analysis, compared with the NG, one new type of ginsenoside was observed in the NAR and 2 MAR lines, and another new type of ginsenoside was observed in the 2 MAR lines irradiated with gamma rays. The ginsenoside content of the MAR 5-9 line was significantly greater in comparison to the NG.

Anti-inflammatory effect of austroinulin and 6-O-acetyl-austroinulin from Stevia rebaudiana in lipopolysaccharide-stimulated RAW264.7 macrophages.

Austroinulin (AI) and 6-O-acetyl-austroinulin (6-OAAI) are natural diterpenoids isolated from Stevia rebaudiana with anti-inflammatory activity. However, the mechanisms underlying their anti-inflammatory effects are not well understood. The purpose of this study was to investigate the effect of AI and 6-OAAI on nitric oxide (NO) production and their molecular mechanism in LPS-stimulated RAW264.7 macrophages. We found that AI and 6-OAAI inhibit the production of NO, iNOS, and pro-inflammatory cytokines (TNF-α, IL-6, IL-1ß, and MCP-1) in LPS-stimulated RAW264.7 macrophages. In these same cells, AI and 6-OAAI also suppressed the phosphorylation of STAT1 and the production of interferon-beta (IFN-ß). Moreover, treatment with AI and 6-OAAI inhibited the activation of interferon regulatory factor-3 (IRF3) and NF-κB. Taken together, our results suggest that AI and 6-OAAI inhibit NO production and iNOS expression by blocking the activation of STAT1, IRF3, and NF-κB in LPS-stimulated RAW264.7 macrophages.

Hepatoprotective effect of 2,3-dehydrosilybin on carbon tetrachloride-induced liver injury in rats.

The aim of this study was to investigate the protective effect of 2,3-dehydrosilybin (DHS) against carbon tetrachloride (CCl(4))-induced liver injury in rats. Administration of DHS significantly attenuated the levels of serum aspartate aminotransferase, alanine aminotransferase, and liver lipid peroxidation in CCl(4)-treated rats. Moreover, we showed that DHS prevented DNA damage and decreased the protein levels of γ-H2AX, which is a specific DNA damage marker, in CCl(4)-treated rat livers. DHS also markedly increased the activity of antioxidant enzymes, such as superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in CCl(4)-treated rat livers. Furthermore, we found that DHS significantly inhibited the production of serum nitric oxide as well as the levels of serum IL-6, IFN-γ, and TNF-α in CCl(4)-treated rats. Additionally, DHS significantly suppressed iNOS expression on the protein levels in CCl(4)-treated rat livers. Collectively, the present study suggests that DHS protects the liver from CCl(4)-induced hepatic damage via antioxidant and anti-inflammatory mechanisms.

Anticholinesterase potential of flavonols from paper mulberry (Broussonetia papyrifera) and their kinetic studies.

It is necessary to develop food additives to help treat chronic disorders like neurodegenerative diseases from medicinal plants. Ethanol extracts of paper mulberry were found to display significant inhibition against cholinesterases, enzymes that are strongly linked with Alzheimer's disease (AD). The active components were identified as prenylated flavonols (2-4) that inhibited two related human cholinesterases in a dose-dependent manner, with IC50's ranging between 0.8 and 3.1µM and between 0.5 and 24.7µM against human acetylcholinesterase (hAChE) and butylcholinesterase (BChE), respectively. Prenyl groups within these flavonols were found to play a critical role for inhibition because the parent compound 1, quercetin, was inactive (IC50>500µM) towards the target enzymes. Flavonols (2-4) showed mixed inhibition kinetics as well as slow and time-dependent reversible inhibition toward hAChE. The affinity between protein and inhibitors was investigated using fluorescence quenching. The affinity constants (KSA) of inhibitors increased in proportion to their inhibitory potencies.

Blackberry extract attenuates oxidative stress through up-regulation of Nrf2-dependent antioxidant enzymes in carbon tetrachloride-treated rats.

The aim of this study was to investigate the protective ability of blackberry extract (BE) against oxidative stress in carbon tetrachloride (CCl(4))-treated rats. The results showed that treatment with BE attenuated lipid peroxidation that was increased by CCl(4) and also markedly recovered the activity of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR), that were decreased by CCl(4). BE also elevated the protein expression levels of NF-E2-related factor-2 (Nrf2), CuZnSOD, MnSOD, GPx-1/2, and heme oxygenase-1 (HO-1), but not that of catalase. Furthermore, the administration of BE significantly attenuated the levels of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) that were increased by CCl(4). Therefore, the present study suggests that BE possesses significant protective effects against in vivo oxidative stress.

Biological evaluation of isoegomaketone isolated from Perilla frutescens and its synthetic derivatives as anti-inflammatory agents.

The anti-inflammatory activities of a prepared isoegomaketone 3a and its derivatives 3b-3f were evaluated in RAW 264.7 cells. Among these, the compound 3d was displayed the most potent inhibitory activities against production of nitric oxide, monocyte chemoattractant protein-1 and interleukin-6. Based on these results, the abilities of compounds 3a-3f to modulate NF-κB and AP-1-mediated gene transcription using a luciferase reporter assay were investigated. The transcriptional activities of NF-κB and AP-1 decreased when pretreated with 3a-3f. Interestingly, at 10 µM, compound 3d markedly suppressed the lipopolysaccharide-induced NF-κB and activator protein-1 DNA binding activities. Some preliminary structure-activity relationships were proposed that may provide a direction for further study.

Gamma-radiation induced modifications in substrate specificity of glucose dehydrogenase and carbon source utilization pattern of phosphate-solubilizing Pantoea strains.

Glucose, maltose, and mannose as sole carbon sources, induced synthesis of glucose dehydrogenase (GDH) in three strains of Pantoea with specific activities from 0.14 to 0.6 U/mg proteins. Utilization of lactose indicated that the enzyme belongs to GDH type B isozyme. Of mutant clones, developed through radiation mutagenesis, P2-M2 utilized ribose with GDH specific activity of 0.57 U/mg protein, P4-M3 grown on glucose gave 1.5 U/mg protein and P4-M5 had high activities, when grown on galactose, maltose, and lactose. Clones P3-M2 and P2-M5 had versatile utilization of sugars and released higher amounts of P from tri-calcium phosphate and can be efficiently used for biofertilization.

Isoegomaketone induces apoptosis through caspase-dependent and caspase-independent pathways in human DLD1 cells.

Isoegomaketone (IK) is an essential oil component of Perilla frutescens (L.), but the mechanism by which IK induces apoptosis has never been studied. The purpose of this study was to elucidate the IK-induced apoptotic pathway in DLD1 human colon cancer cells. We observed that IK treatment over 24 h significantly inhibited cell viability in a dose-dependent manner. We also found that IK triggered cleavage of PARP. Moreover, IK treatment resulted in cleavage of caspase-8, -9, and -3 in a dose- and time-dependent manner. IK treatment also resulted in cleavage of Bid and translocation of Bax, and triggered the release of cytochrome c from the mitochondria to the cytoplasm. Furthermore, it resulted in the translocation of apoptosis inducing factor (AIF), a caspase-independent mitochondrial apoptosis factor, from the mitochondria into the nucleus. Overall, these results suggest that IK induces apoptosis through caspase-dependent and capase-independent pathways in DLD1 cells.

Decursin from Angelicagigas Nakai induces apoptosis in RC-58T/h/SA#4 primary human prostate cancer cells via a mitochondria-related caspase pathway.

Decursin is a major biological active component of Angelicagigas Nakai and is known to induce apoptosis of metastatic prostatic cancer cells. However, the apoptotic mechanism of decursin using primary malignant tumor (RC-58T/h/SA#4)-derived human prostate cells is not known. In the present study, we show that treatment of prostate cancer cells with decursin inhibited cell proliferation in a dose-dependent manner. Decursin also induced apoptosis in RC-58T/h/SA#4 cells, as determined by flow cytometry, Hoechst 33258 staining, and DNA fragmentation. Decursin caused activation of caspases-8, -9, and -3 and promoted the apoptotic action of caspase-8-mediated Bid cleavage. Decursin increased the protein levels of Bax and cytosolic cytochrome c as well as cleavage of PARP while decreasing the protein levels of Bcl-2. Furthermore, the caspase-independent mitochondrial apoptosis factor, apoptosis-inducing factor (AIF), was upregulated by treatment with decursin. Taken together, these findings indicate that decursin inhibited the proliferation of RC-58T/h/SA#4 cells through induction of apoptosis, which is mediated by both caspase-dependent and -independent apoptotic pathways.

Apoptotic action of ursolic acid isolated from Corni fructus in RC-58T/h/SA#4 primary human prostate cancer cells.

Ursolic acid (3ß-hydroxy-urs-12-en-28-oic acid) is a major biological active component of Corni fructus that is known to induce apoptosis. However, the apoptotic mechanism of ursolic acid using primary malignant tumor (RC-58T/h/SA#4)-derived human prostate cells is not known. In the present study, ursolic acid significantly inhibited the growth of RC-58T/h/SA#4 cells in dose- and time-dependent manners. Ursolic acid induced cell death as evidenced by an increased proportion of cells in sub-G1 phase, the formation of apoptotic bodies, nuclear condensation, and DNA fragmentation. After ursolic acid treatment at concentrations above 40 µM, the activities of caspase-3, -8, and -9 were significantly increased compared that of control. Ursolic acid modulated the upregulation of Bax (pro-apoptotic) as well as the downregulation of Bcl-2 (anti-apoptotic). Ursolic acid also stimulated Bid cleavage, which indicates that the apoptotic action of caspase-8-mediated Bid cleavage leads to the activation of caspase-9. Thus, the apoptotic effect of ursolic acid was involved in extrinsic and intrinsic signaling pathways. In addition, ursolic acid increased the expression of the caspase-independent mitochondrial apoptosis factor (AIF) in RC-58T/h/SA#4 cells. The present results suggest that ursolic acid from Corni fructus activated apoptosis in RC-58T/h/SA#4 cells via both caspase-dependent and -independent pathways.

Isoegomaketone inhibits lipopolysaccharide-induced nitric oxide production in RAW 264.7 macrophages through the heme oxygenase-1 induction and inhibition of the interferon-beta-STAT-1 pathway.

Isoegomaketone (IK) is an essential oil component of Perilla frutescens (L.) Britt., and there have been no studies investigating its biological activities. We found that IK inhibits lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 macrophages, and moreover, when IK was injected into animals prior to LPS administration, NO serum levels decreased in a dose-dependent manner. These results indicate that IK possesses anti-inflammatory activity both in vitro and in vivo. IK suppressed the phosphorylation of STAT-1 and the production of IFN-beta. Treatment with IK also inhibited the activation of NF-kappaB and activator protein-1, but more IK was required for inhibition than for STAT-1 inhibition, indicating that downregulation of inducible nitric oxide synthase gene expression by IK is mainly attributed to the blockade of STAT-1 activation. Furthermore, IK also induced the expression of heme oxygenase-1 (HO-1) through the activation of nuclear factor E2-related factor 2. Treatment with SnPP, a selective inhibitor of HO-1, reversed the IK-induced suppression of STAT-1 phosphorylation and NO production. Taken together, IK isolated from P. frutescens inhibits NO production in LPS-treated RAW 264.7 macrophages through simultaneous induction of HO-1 and inhibition of the IFN-beta-STAT-1 pathway.

Anti-proliferative effects of Lethariella zahlbruckneri extracts in human HT-29 human colon cancer cells.

This study was performed to elucidate the anti-proliferative effects and the apoptotic mechanisms of extracts from Lethariella zahlbruckneri in HT-29 human colon cancer cells. Both the acetone extract (AEL) and methanolic extract (MEL) of L. zahlbruckneri decreased viable cell numbers in a dose- and time-dependent manner in HT-29 cells. The AEL showed stronger cytotoxicity than MEL. Cell death induced by AEL increased cell populations in the sub-G1 phase, as well as the formation of apoptotic bodies and nuclear condensation, whereas MEL did not. Therefore, the potential of AEL to induce apoptosis was examined. Apoptosis induced by AEL was associated with the activation of initiator caspases-8 and -9, as well as the effector caspase-3. AEL stimulated Bid cleavage. This indicated that the apoptotic action of caspase-8-mediated Bid cleavage leads to the activation of caspase-9. AEL increased the expression of the pro-apoptotic protein, Bax, and decreased the expression of the anti-apoptotic protein, Bcl-2. AEL also increased the expression of the caspase-independent mitochondrial apoptosis factor, AIF, in HT-29 cells. These results indicate that AEL inhibited HT-29 cell proliferation by inducing apoptosis, which might be mediated via both caspase-dependent and -independent pathways.

Mechanisms of thiosulfinates from Allium tuberosum L.-induced apoptosis in HT-29 human colon cancer cells.

This study was performed to elucidate the apoptotic pathways by thiosulfinates, major biologically active components of Allium tuberosum L., in HT-29 human colon cancer cells. Thiosulfinates significantly induced cell death in dose- and time-dependent manners in HT-29 cells, which is associated with apoptosis. Thiosulfinates activated the initiator caspase-8, and -9, and the effector caspase-3. In the present study, thiosulfinates were found to stimulate Bid cleavage, indicating that the apoptotic action of caspase-8-mediated Bid cleavage leads to the activation of caspase-9. Thiosulfinates down-regulated the expression of the anti-apoptotic protein Bcl-2, and up-regulated the expression of the pro-apoptotic protein Bax. We also found that thiosulfinates increased the expression of AIF, a caspase-independent mitochondrial apoptosis factor, and induced DNA fragmentation and chromatin condensation in HT-29 cells. These results indicate that thiosulfinates from A. tuberosum L. inhibited cell proliferation and activated both the caspase-dependent and caspase-independent apoptotic pathways in HT-29 cells.