An effective strategy for increasing the radiosensitivity of Human lung Cancer cells by blocking Nrf2-dependent antioxidant responses.

Radiotherapy and chemotherapeutic agents can effectively induce apoptosis through generation of reactive oxygen species (ROS). Cancer cells frequently express high levels of ROS-scavenging enzymes, which confer resistance to ROS-mediated cell death. Keap1 (Kelch-like ECH-associated protein 1) sequesters and promotes the degradation of the antioxidant response element-binding transcription factor Nrf2 (nuclear factor erythroid-2-related factor 2). In non-small-cell lung cancer (NSCLC) cell lines and NSCLC patients, Keap1 is often present as a biallelic mutant that results in constitutive activation of Nrf2 function, which contributes to cytoprotection against oxidative stress and xenobiotics. To identify small molecules that inhibit antioxidant responses and increase apoptotic death after radiotherapy, we screened a chemical library containing 8000 synthetic compounds using a cell-based luciferase assay system. 4-(2-Cyclohexylethoxy)aniline (IM3829) inhibited the increase in Nrf2-binding activity and expression of the Nrf2 target genes induced by treatment with tertiary butylhydroquinone or radiation. Combined treatment with IM3829 and radiation significantly inhibited clonogenic survival of H1299, A549, and H460 lung cancer cells. IM3829 significantly increased ROS accumulation in irradiated cells compared with cells exposed to radiation alone and led to apoptotic cell death, as confirmed by caspase-3 and PARP cleavage. In mice bearing H1299 or A549 lung cancer xenografts, IM3829 together with radiation inhibited tumor growth more effectively than radiation alone. Our findings suggest that IM3829 could be a promising radiosensitizer in lung cancer patients, particularly those with high expression of Nrf2.

The inhibitory effect of ginsan on TGF-ß mediated fibrotic process.

Transforming growth factor-beta (TGF-ß) plays a central role in the development of fibrosis by stimulating extracellular matrix accumulation, and signals either directly or indirectly through types I, II, and III (TßRI, II, and III) TGF-ß receptor complexes. Ginsan, a polysaccharide extracted from Panax ginseng, has multiple immunomodulatory effects. Here, we examine whether ginsan regulates the fibrogenic process by interfering with TGF-ß signaling pathways. TGF-ß treatment of murine or human normal lung fibroblasts enhanced the levels of several fibrotic markers, including smooth muscle alpha actin (α-SMA), collagen-1, and fibronectin. Interestingly, ginsan treatment either before or after TGF-ß administration led to significant reductions in all of α-SMA, collagen-1, and fibronectin expression levels. Ginsan not only inhibited phosphorylation of Smad2 and Smad3, but also attenuated pERK and pAKT signaling induced by TGF-ß. Moreover, ginsan restored TßRIII protein expression, which was significantly downregulated by TGF-ß, but reduced TßRI and TßRII protein levels. In a murine model of bleomycin (BLM)-induced pulmonary fibrosis, ginsan significantly suppressed accumulation of collagen, α-SMA, and TGF-ß. These data collectively suggest that ginsan acts as an effective anti-fibrotic agent in the treatment of pulmonary fibrosis by blocking multiple TGF-ß signaling pathways.

IM-412 inhibits transforming growth factor beta-induced fibroblast differentiation in human lung fibroblast cells.

Pulmonary fibrosis is a type of interstitial lung disease that causes progressive scarring in lung tissues. Although there have been many studies on fibrosis, there is no standard treatment for fibrotic disease. Thus, there is an urgent need for the development of effective anti-fibrotic drugs. Transforming growth factor beta (TGF-beta) is a major fibrotic mediator known to stimulate fibrosis. To identify small molecules that inhibit TGF-beta responses, we performed cell-based chemical screening using genetically engineered HEK293 reporter cells. Among 8000 chemical compounds containing biologically active natural products and synthetic or clinically used compounds, we found that 3-(2-chlorobenzyl)-1,7-dimethyl-1H-imidazo[2,1-f]purine-2,4(3H,8H)-dione (IM-412) significantly decreased TGF-beta stimulated reporter activity in a dose-dependent manner. In addition, IM-412 inhibited TGF-beta-induced expression of the fibrotic markers alpha-smooth muscle actin (alpha-SMA) and fibronectin, and collagen accumulation in CCD-18Lu human normal lung fibroblasts without cell cytotoxicity. IM-412 decreased Smad2 and -3 phosphorylation as well as JNK and ERK activity. Moreover, expression levels of TGF-beta receptor I (TbetaRI) and receptor II (TbetaRII) were down-regulated by IM-412 in a dose-dependent manner. Thus, our findings indicate that the small molecule IM-412 attenuated TGF-beta-mediated fibroblast differentiation through inhibition of the overall TGF-beta response and may be a promising novel agent for the treatment of pathological fibrotic conditions.

Sustained expression of NADPH oxidase 4 by p38 MAPK-Akt signaling potentiates radiation-induced differentiation of lung fibroblasts.

Radiation-induced fibrosis (RIF) is a long-term adverse effect of curative radiotherapy; however, the distinct molecular mechanisms of RIF in neighboring normal tissue are not fully understood. We investigated the mechanisms underlying radiation-induced fibroblast differentiation into myofibroblasts. Lung fibroblasts produced reactive oxygen species (ROS) immediately after irradiation, the level of which remained increased for 24 h. The NADPH oxidase inhibitor, diphenyleneiodonium (DPI), suppressed ROS production and significantly decreased the radiation-induced expression of alpha-smooth muscle actin (alpha-SMA) and fibronectin (FN). The mRNA and protein expression of Nox4 was increased by radiation, and siRNA knockdown of Nox4 reduced alpha-SMA and FN levels. Increased phosphorylation of p38MAPK, Erk, and PI3k/Akt was observed after irradiation. Inhibitors of p38 MAPK and Akt, but not of Erk, reduced radiation-induced fibroblast differentiation and Nox4 expression. Notably, DPI partially decreased phosphorylation of p38MAPK and Akt, suggesting that p38MAPK, Akt, and Nox4 may cooperate in a positive feedback loop. Nox4 expression was also increased during bleomycin-induced fibroblast differentiation, and downregulation of Nox4 reduced alpha-SMA levels and extracellular matrix (ECM) accumulation. These results demonstrate that interfering Nox4 activation can be a potential strategy to disrupt fibrotic process.

Inhibition of type III TGF-ß receptor aggravates lung fibrotic process.

Transforming growth factor-beta (TGF-ß) is a multifunctional cytokine that regulates cell proliferation, death, development or differentiation. In addition, TGF-ß is considered a key mediator in fibrogenic processes, and signals either directly or indirectly through types I, II and III (TßRI, II, and III) receptor complexes. The type III TGF-ß (TßRIII or betaglycan) is a transmembrane proteoglycan without a functional kinase domain, and is considered as a coreceptor to increase the affinity of ligand binding to TßRII. Little is studied on TGF-ß and TßRIII (or betaglycan) signaling, while it is well known about TGF-ß ligand and TßRII signaling. In this study, we investigated the effects of TßRIII expression on TGF-ß induced differentiation, in view of the finding that TßRIII is significantly downregulated during TGF-ß-induced differentiation in fibroblasts. TGF-beta induced alpha-SMA and Procollagen Type I expression were markedly inhibited in fibroblasts stably expressing TßRIII. Endogenous TßRIII expression did not alter the TßRI or TßRII levels, but inhibited Smad 2/3, Akt and ERK phosphorylation. The molecular mechanism of TßRIII action in TGF-ß-induced differentiation is associated with both Smad-dependent and Smad-independent pathways. Our results suggest that TßRIII is a novel molecular target for regulation of TGF-ß signaling in myofibroblast differentiation.

Ginsan enhances humoral antibody response to orally delivered antigen.

BACKGROUND: There have been several reports describing the capability of ginseng extracts as an adjuvant. In this study, we tested if ginsan, a polysaccharide extracted from Panax ginseng, was effective in enhancing antibody response to orally delivered Salmonella antigen. METHODS: Ginsan was treated before oral salmonella antigen administration. Salmonella specific antibody was determined by ELISA. mRNA expression was determined by RT-PCR. Cell migration was determined by confocal microscopy and flow cytometry. COX expression was detected by western blot. RESULTS: Ginsan treatment before oral Salmonella antigen delivery significantly increased both secretory and serum antibody production. Ginsan increased the expression of COX in the Peyer's patches. Various genes were screened and we found that CCL3 mRNA expression was increased in the Peyer's patch. Ginsan increased dendritic cells in the Peyer's patch and newly migrated dendritic cells were mostly found in the subepithelial dome region. When COX inhibitors were treated, the expression of CCL3 was reduced. COX inhibitor also antagonized both the migration of dendritic cells and the humoral immune response against oral Salmonella antigen. CONCLUSION: Ginsan effectively enhances the humoral immune response to orally delivered antigen, mediated by CCL3 via COX. Ginsan may serve as a potent vaccine suppliment for oral immunization.

Protective action of the immunomodulator ginsan against carbon tetrachloride-induced liver injury via control of oxidative stress and the inflammatory response.

The aim of the present study was to evaluate immunomodulator ginsan, a polysaccharide extracted from Panax ginseng, on carbon tetrachloride (CCl(4))-induced liver injury. BALB/c mice were injected i.p. with ginsan 24 h prior to CCl(4) administration. Serum liver enzyme levels, histology, expression of antioxidant enzymes, and several cytokines/chemokines were subsequently evaluated. Ginsan treatment markedly suppressed the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and hepatic histological necrosis increased by CCl(4) treatment. Ginsan inhibited CCl(4) induced lipid peroxidation through the cytochrome P450 2E1 (CYP2E1) downregulation. The hepatoprotective effect of ginsan was attributed to induction of anti-oxidant protein contents, such as superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPX) as well as restoration of the hepatic glutathione (GSH) concentration. The marked increase of proinflammatory cytokines (IL-1beta, IFN-gamma) and chemokines (MCP-1, MIP-2beta, KC) in CCl(4) treated mice was additionally attenuated by ginsan, thereby preventing leukocyte infiltration and local inflammation. Our results suggest that ginsan effectively prevent liver injury, mainly through downregulation of oxidative stress and inflammatory response.

Immunomodulatory activity of ginsan, a polysaccharide of panax ginseng, on dendritic cells.

Ginsan, a Panax ginseng polysaccharide that contains glucopyranoside and fructofuranoside, has immunomodulatory effects. Although several biologic studies of ginsan have been performed, its effects on dendritic cells (DCs), which are antigen-presenting cells of the immune system, have not been studied. We investigated the immunomodulatory effects of ginsan on DCs. Ginsan had little effect on DC viability, even when used at high concentrations. Ginsan markedly increased the levels of production by DCs of IL-12 and TNF-alpha, as measured by ELISA. To examine the maturation-inducing activity of ginsan, we measured the surface expression levels of the maturation markers MHC class II and CD86 (B7.2) on DCs. It is interesting that ginsan profoundly enhanced the expression of CD86 on DC surfaces, whereas it increased that of MHC class II only marginally. In (3)H-thymidine incorporation assays, ginsan-treated DCs stimulated significantly higher proliferation of allogeneic CD4(+) T lymphocytes than did medium-treated DCs. Taken together, our data demonstrate that ginsan stimulates DCs by inducing maturation. Because DCs are critical antigen-presenting cells in immune responses, this study provides valuable information on the activities of ginsan.

Isoreserpine promotes beta-catenin degradation via Siah-1 up-regulation in HCT116 colon cancer cells.

Aberrant accumulation of intracellular beta-catenin in intestinal epithelial cells is a frequent early event during the development of colon cancer. To identify small molecules that decrease the level of intracellular beta-catenin, we performed cell-based chemical screening using genetically engineered HEK293 reporter cells to detect compounds that inhibit TOPFlash reporter activity, which was stimulated by Wnt3a-conditioned medium. We found that isoreserpine promoted the degradation of intracellular beta-catenin by up-regulation of Siah-1 in HEK293 and HCT116 colon cancer cells. Moreover, isoreserpine repressed the expression of beta-catenin/T-cell factor (TCF)-dependent genes, such as cyclin D1 and c-myc, resulting in the suppression of HCT116 cell proliferation. Our findings suggest that isoreserpine can potentially be used as a chemotherapeutic agent against colon cancer.

N,N-dimethyl phytosphingosine induces caspase-8-dependent cytochrome c release and apoptosis through ROS generation in human leukemia cells.

N,N-dimethyl phytosphingosine (DMPS) blocks the conversion of sphingosine to sphingosine-1-phosphate (S1P) by the enzyme sphingosine kinase (SK). In this study, we elucidated the apoptotic mechanisms of DMPS action on a human leukemia cell line using functional pharmacologic and genetic approaches. First, we demonstrated that DMPS-induced apoptosis is evidenced by nuclear morphological change, distinct internucleosomal DNA fragmentation, and an increased sub-G1 cell population. DMPS treatment led to the activation of caspase-9 and caspase-3, accompanied by the cleavage of poly(ADP-ribose) polymerase (PARP) and led to cytochrome c release, depolarization of the mitochondrial membrane potential, and downregulation of the anti-apoptotic members of the bcl-2 family. Ectopic expression of bcl-2 and bcl-xL conferred resistance of HL-60 cells to DMPS-induced cell death, suggesting that DMPS-induced apoptosis occurs predominantly through the activation of the intrinsic mitochondrial pathway. We also observed that DMPS activated the caspase-8-Bid-Bax pathway and that the inhibition of caspase-8 by z-IETD-fmk or small interfering RNA suppressed the cleavage of Bid, cytochrome c release, caspase-3 activation, and apoptotic cell death. In addition, cells subjected to DMPS exhibited significantly increased reactive oxygen species (ROS) generation, and ROS scavengers, such as quercetin and Tiron, but not N-acetylcysteine (NAC), inhibited DMPS-induced activations of caspase-8, -3 and subsequent apoptotic cell death, indicating the role of ROS in caspase-8-mediated apoptosis. Taken together, these results indicate that caspase-8 acts upstream of caspase-3, and that the caspase-8-mediated mitochondrial pathway is important in DMPS-induced apoptosis. Our results also suggest that ROS are critical regulators of caspase-8-mediated apoptosis in DMPS-treated leukemia cells.

Suppressive effects of ginsan on the development of allergic reaction in murine asthmatic model.

BACKGROUND: Asthma is a major health problem worldwide, and the morbidity and mortality caused by asthma are on the rise. Corticosteroid therapies for asthma treatment frequently induce many side effects. Therefore, the development of new medicines that have both high efficacy and fewer side effects has been a scientific challenge. Here we tested the effect of ginsan, a polysaccharide derived from Panax ginseng, against allergic reaction in an ovalbumin (OVA)-induced murine asthmatic model in comparison with dexamethasone, and investigated its underlying mechanism. METHODS: To induce murine asthma, mice were sensitized and challenged with OVA. Ginsan or dexamethasone was administered by injection 3 times a week. Airway hyperresponsiveness, airway inflammation and lung pathology were assessed in order to evaluate the effect of ginsan against asthma. RESULTS: Ginsan treatment reduced airway hyperresponsiveness, remodeling and eosinophilia. These effects of ginsan were equivalent to those of dexamethasone. Ginsan treatment decreased the IL-5 level in the supernatant of cultured splenocytes, while IFN-gamma and serum IgE were not altered. To elucidate the mechanism of ginsan, expression of inflammation-related genes were screened. Interestingly, ginsan treatment upregulated cyclooxygenase (COX)-1 and COX-2 mRNA, and expression of their proteins in the lung were also increased. PGE(2) in the bronchoalveolar lavage fluid was also increased by the ginsan treatment. Lastly, ginsan inhibited the allergic reaction aggravated by COX inhibitor (indomethacin). CONCLUSION: Ginsan has anti-asthmatic effects, which seem to be partially mediated by enhancing the synthesis of COX gene products.

Nimesulide, a selective COX-2 inhibitor, acts synergistically with ionizing radiation against A549 human lung cancer cells through the activation of caspase-8 and caspase-3.

Several lines of evidence suggest that non-steroidal anti-inflammatory drugs (NSAIDs) have a radiosensitizing effect on cancer cells in vitro and in vivo, but little is known about the underlying cellular mechanism. In this study, we found that the treatment with the NSAID nimesulide significantly increased the sensitivity of A549 human non-small cell lung cancer cells to radiotherapy. The combined nimesulide-radiation treatment increased apoptosis, induced the cleavage of caspase-3, caspase-9, and poly(ADP-ribose) polymerase (PARP), activated caspase-8, and induced cleavage of Bid. A pan-caspase inhibitor, z-VAD-fmk, suppressed this increase in apoptosis and also suppressed the cleavage of caspase-8, caspase-3, and PARP, suggesting a caspase-dependent mechanism. In addition, z-IETD-fmk, a selective caspase-8 inhibitor, suppressed the nimesulide- and radiation-induced cleavage activation of caspase-9, caspase-3, caspase-8, and Bid, and suppressed the concomitant apoptosis, indicating that the nimesulide-induced increase in radiosensitivity was initiated by caspase-8. However, the caspase-3 inhibitor z-DEVD-fmk failed to suppress activation of the caspase-8/Bid pathway, indicating that caspase-3 activation occurred downstream of caspase-8 activation in our experiments. Marked antitumor effects, which were evaluated by measuring protracted tumor regression, were observed when nude mice were treated with a combination of nimesulide at a clinically achievable dose (0.5 mg/kg) and radiation therapy. Our results, demonstrating the radiosensitivity-increasing and tumor growth-inhibiting effects of nimesulide, suggest that nimesulide may be suitable as an adjuvant to enhance the efficacy and selectivity of radiotherapy.

Natural derivatives of curcumin attenuate the Wnt/beta-catenin pathway through down-regulation of the transcriptional coactivator p300.

Curcumin, a component of turmeric (Curcuma longa), has been reported to suppress beta-catenin response transcription (CRT), which is aberrantly activated in colorectal cancer. However, the effects of its natural analogs (demethoxycurcumin [DMC] and bisdemethoxycurcumin [BDMC]) and metabolite (tetrahydrocurcumin [THC]) on the Wnt/beta-catenin pathway have not been investigated. Here, we show that DMC and BDMC suppressed CRT that was activated by Wnt3a conditioned-medium (Wnt3a-CM) without altering the level of intracellular beta-catenin, and inhibited the growth of various colon cancer cells, with comparable potency to curcumin. Additionally, DMC and BDMC down-regulated p300, which is a positive regulator of the Wnt/beta-catenin pathway. Notably, THC also inhibited CRT and cell proliferation, but to a much lesser degree than curcumin, DMC, or BDMC, indicating that the conjugated bonds in the central seven-carbon chain of curcuminoids are essential for the inhibition of Wnt/beta-catenin pathway and the anti-proliferative activity of curcuminoids. Thus, our findings suggest that curcumin derivatives inhibit the Wnt/beta-catenin pathway by decreasing the amount of the transcriptional coactivator p300.

N-acetylphytosphingosine enhances the radiosensitivity of lung cancer cell line NCI-H460.

Ceramides are well-known second messengers that induce apoptosis in various kinds of cancer cells, and their effects are closely related to radiation sensitivity. Phytoceramides, the yeast counterparts of the mammalian ceramides, are also reported to induce apoptosis. We investigated the effect of a novel ceramide derivative, N-acetylphytosphingosine (NAPS), on the radiosensitivity of NCI-H460 human lung carcinoma cells and its differential cytotoxicity in tumor and normal cells. The combination of NAPS with radiation significantly increased clonogenic cell death and caspase-dependent apoptosis. The combined treatment greatly increased Bax expression and Bid cleavage, but not Bcl-2 expression. However, there was no effect on radiosensitivity and apoptosis in BEAS2B cells, which derive from normal human bronchial epithelium. Cell proliferation and DNA synthesis were significantly inhibited by NAPS in both NCI-H460 and BEAS2B cells, but only the BEAS2B cells recovered by 48h after removal of the NAPS. Furthermore, the NCI-H460 cells underwent more DNA fragmentation than the BEAS2B cells in response to NAPS. Our results indicate that NAPS may be a potential radiosensitizing agent with differential effects on tumor vs. normal cells.

Effect of gamma radiation on cytokine expression and cytokine-receptor mediated STAT activation.

PURPOSE: The expression of cytokine mRNA and their related transcription factors was examined in order to assess the effects of gamma radiation on the immune function of murine splenocytes. MATERIALS AND METHODS: Splenocytes were collected from seven-week-old female Balb/c mice, and then irradiated at a dose of 5 Gy of 60Co gamma-ray at a dose rate of 1.394 Gy/min. Total RNA was extracted from both irradiated and non-irradiated splenocytes at 1/2, 1, 3, 6, and 24 h and analysed by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The mRNA level of interferon (IFN)-gamma, which is a Th1-type (T helper cell type 1) cytokine, was reduced after 3 h post-irradiation, whereas the interleukin (IL)-2 mRNA in the naïve splenocytes had no significant changes within the 24 h after irradiation. Moreover, IFN-gamma and IL-2 mRNA expression in concanavalin A (Con A, 2.5 mug/ml) activated-splenocytes was significantly reduced by gamma irradiation. On the other hand, the mRNA level of the Th2 type (T helper cell type 2) cytokines, such as IL-4, IL-5 and IL-10, was increased both in naïve and activated splenocytes, and pro-inflammatory cytokines were also rapidly induced in response to irradiation in naïve splenocytes. Interestingly, gamma irradiation had no effect on transforming growth factor (TGF)-beta mRNA expression. Moreover, the mRNA levels of the leucine zipper trqnscription factor c-Maf and GATA binding protein-3 (GATA-3), which regulate IL-4 and IL-5 transcription, were found to have been up-regulated. However, the mRNA coding for interferon regulatory factor (IRF)-1, which is involved in IFN-gamma production, was reduced 6 h post-irradiation. The level of signal transducers and activators of transcription (Stat)-1 and Stat-4 phosphorylation, which are activated by IFN-gamma and IL-12, respectively, was significantly reduced by gamma irradiation, but IL-4 receptor mediated Stat-6 activation remained unchanged. CONCLUSIONS: These results suggest that gamma irradiation may play a role in Th1 and Th2 cytokine expression, via regulation of the level of cytokine-mediators through transcriptional modulation and Stat signaling. These results are helpful to understand general profile of cytokine expression in response to gamma irradiation.

Protection of Staphylococcus aureus-infected septic mice by suppression of early acute inflammation and enhanced antimicrobial activity by ginsan.

Ginsan, an acidic polysaccharide prepared from Panax ginseng, demonstrated multiple immunomodulatory effects in previous studies. This study was conducted to elucidate the antiseptic mechanism induced by ginsan in mice infected with Staphylococcus aureus. When mice were treated with ginsan before the bacterial challenge with S. aureus, they were highly protected from sepsis-induced death. The numbers of S. aureus recovered from ginsan-treated mice were considerably lower than those recovered from nontreated mice. The in vivo depletion of monocytes/macrophages caused more S. aureus to be recovered from the bacteria-infected mice. Nevertheless, mice treated with both etoposide and ginsan were able to maintain an antibacterial activity. In addition, the phagocytic activity of ginsan-treated macrophage against S. aureus was considerably enhanced. The synthesis of inflammatory cytokines, such as tumor necrosis factor-alpha interleukin (IL)-1beta, IL-6, IFN-gamma, IL-12, IL-18 and interferon gamma, was significantly downregulated at the early phase of sepsis in mice that were treated with ginsan before the bacterial challenge. Expression of Toll-like receptors (TLRs), including TLR2, TLR4, and TLR9, as well as the adaptor molecule MyD88, was considerably reduced in peritoneal macrophages that were treated with ginsan before a subsequent contact with S. aureus. These data indicated that ginsan protected mice from S. aureus-induced sepsis through the suppression of acute inflammatory responses at an early phase and the enhancement of antimicrobial activities at subsequent phases of infection.

The immunomodulator ginsan induces resistance to experimental sepsis by inhibiting Toll-like receptor-mediated inflammatory signals.

Ginsan, a polysaccharide extracted from Panax ginseng, has multiple immunomodulatory effects. In this study, we show that pretreatment of ginsan (25 mug/kg) protected mice from lethality induced by Staphylococcus aureus challenge. This survival benefit was associated with enhanced bacterial clearance from circulation, spleen and kidney. The phagocytic activity of macrophages treated with ginsan was significantly enhanced against S. aureus. However, the production of proinflammatory cytokines, such as TNF-alpha, IL-1beta, IL-6, IFN-gamma, IL-12, and IL-18, was markedly down-regulated in ginsan-treated mice compared with those of control-infected mice. The expression of Toll-like receptor (TLR) 2 and the adaptor molecule MyD88, which was greatly increased in septic macrophages, was significantly reduced by ginsan treatment in vitro. Similarly, the expression of phospho-JNK1/2, phospho-p38 MAPK, and NF-kappaB was decreased in the same culture system. These results illustrate that the antiseptic activity of ginsan can be attributed to enhanced bacterial clearance, and reduced proinflammatory cytokines via the TLR signaling pathway.

Antimutagenic effect of polysaccharide ginsan extracted from Panax ginseng.

Ginsan is a polysaccharide extracted from the roots of Panax ginseng, and it has earlier been reported to have an immunostimulatory effect. In the present study, the frequency of micronucleated polychromatic erythrocytes (MNPCE) was assessed in the bone marrow of C57BL/6 male mice treated with ginsan [100, 200 or 300 mg/kg body weight (b.w.)] or amifostine (200mg/kg b.w.) 30 min before as well as 15 min after 1.5 Gy of gamma-irradiation. Ginsan and amifostine did not alter the frequency of MNPCE of control mice (P>0.05), showing that they are non-mutagenic per se; gamma-irradiation induced a statistically significant (P<0.001) increase of MNPCE and decrease of PCE/NCE ratio (P<0.001) compared to control group. However, ginsan applied 30 min before or 15 min after irradiation reduced MNPCE in a dose-dependent manner. Amifostine (200mg/kg b.w.) did not reduce radiation-induced MNPCE, but stimulated erythropoiesis, when administered before irradiation. Based on the above results, radioprotective effect of ginsan can be partially attributed to reduction of radiation-induced genotoxicity.

Overexpression of alpha1-protease inhibitor and galectin-1 in radiation-induced early phase of pulmonary fibrosis.

PURPOSE: Radiation-induced pulmonary fibrosis (RIF) is a significant complication of radiotherapy for lung cancer. Despite the large number of studies, the molecular mechanisms of RIF are poorly understood. Therefore, the complex protein expression pattern in RIF was characterized by identifying the proteins with an altered expression level after thorax irradiation using two-dimensional electrophoresis (2-DE) and mass spectrometry. MATERIALS AND METHODS: A mouse model of RIF was used to examine the alteration of the lung proteome because of availability of murine data related to human cases and the abundance of murine fibrotic lung samples. A mouse model of RIF was induced in radiosensitive C57BL/6 mice. Twenty-one weeks after 25 Gy irradiation, hematoxylin-eosin staining and hydroxyproline assay confirmed the early-phase pulmonary fibrosis. RESULTS: Lung samples from the irradiated and age-matched control mice were used to generate 16 high quality 2-DE gels containing approximately 1,000 spots. Of the 31 significantly up- or down-regulated protein spots, 17 were identified by MALDI-TOF/MS. CONCLUSIONS: Two important upregulated proteins were found, the alpha1-protease inhibitor and galectin-1, which might be used as potential markers for the early phase of RIF.

Modulation of radiation-induced disturbances of antioxidant defense systems by ginsan.

There are numerous studies to indicate that irradiation induces reactive oxygen species (ROS), which play an important causative role in radiation damage of the cell. We evaluated the effects of ginsan, a polysaccharide fraction extracted from Panax ginseng, on the gamma-radiation induced alterations of some antioxidant systems in the spleen of Balb/c mice. On the 5th day after sublethal whole-body irradiation, homogenized spleen tissues of the irradiated mice expressed only marginally increased mRNA levels of Mn-SOD (superoxide dimutase) in contrast to Cu/Zn-SOD, however, catalase mRNA was decreased by approximately 50% of the control. In vivo treatment of non-irradiated mice with ginsan (100 mg kg(-1), intraperitoneal administration) had no significant effect, except for glutathione peroxidase (GPx) mRNA, which increased to 144% from the control. However, the combination of irradiation with ginsan effectively increased the SODs and GPx transcription as well as their protein expressions and enzyme activities. In addition, the expression of heme oxygenase-1 and non-protein thiol induced by irradiation was normalized by the treatment of ginsan. Evidence indicated that transforming growth factor-beta and other important cytokines such as IL-1, TNF and IFN-gamma might be involved in evoking the antioxidant enzymes. Therefore, we propose that the modulation of antioxidant enzymes by ginsan was partly responsible for protecting the animal from radiation, and could be applied as a therapeutic remedy for various ROS-related diseases.