Ju-Hee Kang

Orally administered aqueous extract of Inonotus obliquus ameliorates acute inflammation in dextran sulfate sodium (DSS)-induced colitis in mice.

ETHNOPHARMACOLOGICAL RELEVANCE Chaga mushroom (Inonotus obliquus) has been used in folk medicine to treat several disorders through its various biological functions. I. obliquus is claimed to produce general immune-potentiating and strengthening, antiinflammatory, and antitumor properties, but its effects on intestinal inflammation (ulcerative colitis) are clearly not understood. AIM OF THE STUDY To determine the effects and mode of action of an aqueous extract of I. obliquus (IOAE) on experimental colitis in mice induced by dextran sulfate sodium (DSS). MATERIALS AND METHODS Female 5-week-C57BL/6 mice were randomized into groups differing in treatment conditions (prevention and treatment) and doses of IOAE (50 and 100mg/kg body weight). Mice were exposed to DSS (2%) in their drinking water over 7 day to induce acute intestinal inflammation. In colon tissues, we evaluated histological changes by hematoxylin and eosin staining, levels of iNOS by immuno-histochemical staining, and neutrophil influx by myeloperoxidase assay. mRNA expression of pro-inflammatory mediators TNF-α, IL-1β, IL-6, and IFN-γ was determined by RT-PCR. RESULTS Histological examinations indicated that IOAE suppressed edema, mucosal damage, and the loss of crypts induced by DSS. IOAE markedly attenuated DSS-induced iNOS levels and myeloperoxidase accumulation in colon tissues, demonstrating its suppressive effect on infiltration of immune cells. In addition, IOAE significantly inhibited mRNA expression of pro-inflammatory cytokines induced by DSS in colon tissues. CONCLUSION Our results suggest anti-inflammatory effect of IOAE at colorectal sites due to down-regulation of the expression of inflammatory mediators. Suppression of TNF-α and iNOS together with IL-1β by IOAE denotes that it might be a useful supplement in the setting of inflammatory bowel disease.

Involvement of Cox-2 in the metastatic potential of chemotherapy-resistant breast cancer cells

BackgroundA major problem with the use of current chemotherapy regimens for several cancers, including breast cancer, is development of intrinsic or acquired drug resistance, which results in disease recurrence and metastasis. However, the mechanisms underlying this drug resistance are unknown. To study the molecular mechanisms underlying the invasive and metastatic activities of drug-resistant cancer cells, we generated a doxorubicin-resistant MCF-7 breast cancer cell line (MCF-7/DOX).MethodsWe used MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, flow cytometry assays, DNA fragmentation assays, Western blot analysis, cell invasion assays, small interfering RNA (siRNA) transfection, reverse transcription-polymerase chain reaction, experimental lung metastasis models, and gelatin and fibrinogen/plasminogen zymography to study the molecular mechanism of metastatic activities in MCF-7/DOX cells.ResultsWe found that MCF-7/DOX acquired invasive activities. In addition, Western blot analysis showed increased expression of epidermal growth factor receptor (EGFR) and Cox-2 in MCF-7/DOX cells. Inhibition of Cox-2, phosphoinositide 3-kinase (PI3K)/Akt, or mitogen-activated protein kinase (MAPK) pathways effectively inhibited the invasive activities of MCF-7/DOX cells. Gelatin and fibrinogen/plasminogen zymography analysis showed that the enzymatic activities of matrix metalloproteinase-2 (MMP-2), MMP-9, and urokinase-type plasminogen activator were markedly higher in MCF-7/DOX cells than in the MCF-7 cells. In vitro invasion assays and mouse models of lung metastasis demonstrated that MCF-7/DOX cells acquired invasive abilities. Using siRNAs and agonists specific for prostaglandin E (EP) receptors, we found that EP1 and EP3 played important roles in the invasiveness of MCF-7/DOX cells.ConclusionsWe found that the invasive activity of MCF-7/DOX cells is mediated by Cox-2, which is induced by the EGFR-activated PI3K/Akt and MAPK pathways. In addition, EP1 and EP3 are important in the Cox-2-induced invasion of MCF-7/DOX cells. Therefore, not only Cox-2 but also EP1 and EP3 could be important targets for chemosensitization and inhibition of metastasis in breast cancers that are resistant to chemotherapy.

Lipid raft-dependent death receptor 5 (DR5) expression and activation are critical for ursodeoxycholic acid-induced apoptosis in gastric cancer cells

Ursodeoxycholic acid (UDCA) is known as a suppressor of cholestatic liver diseases and colorectal cancer development. Here, we demonstrate that UDCA induces apoptosis without necrotic features in SNU601, SNU638, SNU1 and SNU216 human gastric cancer cells, implying its possible use as an effective chemotherapeutic agent in treatment of gastric cancer. UDCA-induced apoptosis was dominantly mediated by an extrinsic pathway dependent on caspase-8, -6 and -3. UDCA increased expression of death receptor 5 [(DR5), also known as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 2], and this DR appeared to be responsible for UDCA-induced apoptosis, as evidenced by DR5 knockdown. UDCA triggered formation of lipid rafts that played crucial roles in UDCA-induced apoptotic actions. Lipid rafts were required not only for provision of a proper site for DR5 action but also for mediation of DR5 expression. In addition, reactive oxygen species (ROS) and protein kinase C (PKC) δ appeared to be implicated in UDCA-induced raft-dependent DR5 expression. Our results indicate that UDCA-induced apoptosis is mediated by DR5 expression, which is regulated by the raft formation/ROS production/PKCδ activation pathway and DR5 localization into lipid rafts in gastric cancer cells. Tumor-suppressive activity of UDCA was confirmed in an in vivo system: UDCA (120 mg/kg/day) significantly decreased tumor growth in gastric cancer xenograft mice. Taken together, our results demonstrate that UDCA can be used as a potent chemotherapeutic agent for treatment of gastric cancer.

Ergosterol peroxide from Chaga mushroom (Inonotus obliquus) exhibits anti-cancer activity by down-regulation of the β-catenin pathway in colorectal cancer.

AIM OF THE STUDY In this study, we examined the effect of different fractions and components of Chaga mushroom (Inonotus Obliquus) on viability and apoptosis of colon cancer cells. Among them, one component showed the most effective growth inhibition and was identified as ergosterol peroxide by NMR analysis. We investigated the anti-proliferative and apoptosis mechanisms of ergosterol peroxide associated with its anti-cancer activities in human colorectal cancer (CRC) cell lines and tested its anti-tumor effect on colitis-induced CRC developed by Azoxymethane (AOM)/Dextran sulfate sodium (DSS) in a mouse model. MATERIALS AND METHODS We used MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, flow cytometry assays, Western blot analysis, colony formation assays, reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry (IHC), and AOM/DSS mouse models to study the molecular mechanism of metastatic activities in CRC cells. RESULTS Ergosterol peroxide inhibited cell proliferation and also suppressed clonogenic colony formation in HCT116, HT-29, SW620 and DLD-1 CRC cell lines. The growth inhibition observed in these CRC cell lines was the result of apoptosis, which was confirmed by FACS analysis and Western blotting. Ergosterol peroxide inhibited the nuclear levels of β-catenin, which ultimately resulted in reduced transcription of c-Myc, cyclin D1, and CDK-8. Ergosterol peroxide administration showed a tendency to suppress tumor growth in the colon of AOM/DSS-treated mice, and quantification of the IHC staining showed a dramatic decrease in the Ki67-positive staining and an increase in the TUNEL staining of colonic epithelial cells in AOM/DSS-treated mice by ergosterol peroxide for both prevention and therapy. CONCLUSION Our data suggest that ergosterol peroxide suppresses the proliferation of CRC cell lines and effectively inhibits colitis-associated colon cancer in AOM/DSS-treated mice. Ergosterol peroxide down-regulated β-catenin signaling, which exerted anti-proliferative and pro-apoptotic activities in CRC cells. These properties of ergosterol peroxide advocate its use as a supplement in colon cancer chemoprevention.

Expression of antiviral cytokines in Crandell-Reese feline kidney cells pretreated with Korean red ginseng extract or ginsenosides

The antiviral activity and protective mechanism of Korean red ginseng (KRG) is not well understood. The aim of this study was to investigate the protective mechanism of KRG extract and ginsenosides against feline calicivirus (FCV), a human norovirus surrogate. CRFK cells that were pretreated for 48h with 10μg/mL of KRG extract or purified ginsenoside Rb1 or Rg1, were inoculated with FCV. RNA extracted from each treated group was examined for the expression of antiviral cytokines, including interferon-α (IFN-α), interferon-β (IFN-β), interferon-ω (IFN-ω), Mx, and zinc finger antiviral protein shorter isoform (ZAPS), by relative real-time reverse transcription-polymerase chain reaction. mRNA expression of IFN-α, IFN-β, IFN-ω, Mx, and ZAPS was significantly induced in the FCV-challenged group pretreated with the KRG extract or ginsenosides, and it was higher than the group treated with FCV alone. Mx protein expression was confirmed by western blotting of CRFK cells pretreated with the ginsenoside Rb1 or with Rg1. Induction of antiviral cytokines contributes to the reduction of the viral titer in CRFK cells pretreated with the KRG extract and purified ginsenosides. In future studies, the antiviral protective mechanism of KRG should be demonstrated using other viruses such as human norovirus.

Role of the focal adhesion protein TRIM15 in colon cancer development.

The tripartite motif containing (TRIM) proteins are a large family of proteins that have been implicated in many biological processes including cell differentiation, apoptosis, transcriptional regulation, and signaling pathways. Here, we show that TRIM15 co-localized to focal adhesions through homo-dimerization and significantly suppressed cell migration. Domain mapping analysis indicated that B-box2 and PRY domains were essential for TRIM15 localization to focal adhesions and inhibition of cell migration. Our protein-protein interaction screen of TRIM15 with the integrin adhesome identified several TRIM15 interacting proteins including coronin 1B, cortactin, filamin binding LIM protein1, and vasodilator-stimulated phosphoprotein, which are involved in actin cytoskeleton dynamics. TRIM15 expression was tissue-restricted and downregulated in colon cancer. Level of TRIM15 expression was associated with colon cancer cell migration, as well as both in vitro and in vivo tumor growth. These data provide novel insights into the role of TRIM15 as an additional component of the integrin adhesome, regulating cell migration, and suggest that TRIM15 may function as a tumor suppressor of colon cancer.

Oral administration of fermented wild ginseng ameliorates DSS-induced acute colitis by inhibiting NF-κB signaling and protects intestinal epithelial barrier

Ginseng has been widely used for therapeutic and preventive purposes for thousands of years. However, orally administered ginseng has very low bioavailability and absorption in the intestine. Therefore, fermented ginseng was developed to enhance the beneficial effects of ginseng in the intestine. In this study, we investigated the molecular mechanisms underlying the anti-inflammatory activity of fermented wild ginseng (FWG). We found that FWG significantly alleviated the severity of colitis in a dextran sodium sulfate (DSS)-induced colitis mouse model, and decreased expression level of pro-inflammatory cytokines in colonic tissue. Moreover, we observed that FWG suppressed the infiltration of macrophages in DSS-induced colitis. FWG also attenuated the transcriptional activity of nuclear factor-κB (NF-κB) by reducing the translocation of NF-κB into the nucleus. Our data indicate that FWG contains anti-inflammatory activity via NF-κB inactivation and could be useful for treating colitis. [BMB Reports 2015; 48(7): 419-425]

The novel IGF-IR/Akt–dependent anticancer activities of glucosamine

BackgroundRecent studies have shown that glucosamine inhibits the proliferation of various human cancer cell lines and downregulates the activity of COX-2, HIF-1α, p70S6K, and transglutaminase 2. Because the IGF-1R/Akt pathway is a common upstream regulator of p70S6K, HIF-1α, and COX-2, we hypothesized that glucosamine inhibits cancer cell proliferation through this pathway.MethodsWe used various in vitro assays including flow cytometry assays, small interfering RNA (siRNA) transfection, western blot analysis, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, reverse transcription-polymerase chain reaction, and in vivo xenograft mouse model to confirm anticancer activities of glucosamine and to investigate the molecular mechanism.ResultsWe found that glucosamine inhibited the growth of human non-small cell lung cancer (NSCLC) cells and negatively regulated the expression of IGF-1R and phosphorylation of Akt. Glucosamine decreased the stability of IGF-1R and induced its proteasomal degradation by increasing the levels of abnormal glycosylation on IGF-1R. Moreover, picropodophyllin, a selective inhibitor of IGF-1R, and the IGF-1R blocking antibody IMC-A12 induced significant cell growth inhibition in glucosamine-sensitive, but not glucosamine-resistant cell lines. Using in vivo xenograft model, we confirmed that glucosamine prohibits primary tumor growth through reducing IGF-1R signalling and increasing ER-stress.ConclusionsTaken together, our results suggest that targeting the IGF-1R/Akt pathway with glucosamine may be an effective therapeutic strategy for treating some type of cancer.

Midazolam induces cellular apoptosis in human cancer cells and inhibits tumor growth in xenograft mice

Midazolam is a widely used anesthetic of the benzodiazepine class that has shown cytotoxicity and apoptosisinducing activity in neuronal cells and lymphocytes. This study aims to evaluate the effect of midazolam on growth of K562 human leukemia cells and HT29 colon cancer cells. The in vivo effect of midazolam was investigated in BALB/c-nu mice bearing K562 and HT29 cells human tumor xenografts. The results show that midazolam decreased the viability of K562 and HT29 cells by inducing apoptosis and S phase cell-cycle arrest in a concentration-dependent manner. Midazolam activated caspase-9, capspase-3 and PARP indicating induction of the mitochondrial intrinsic pathway of apoptosis. Midazolam lowered mitochondrial membrane potential and increased apoptotic DNA fragmentation. Midazolam showed reactive oxygen species (ROS) scavenging activity through inhibition of NADPH oxidase 2 (Nox2) enzyme activity in K562 cells. Midazolam caused inhibition of pERK1/2 signaling which led to inhibition of the anti-apoptotic proteins Bcl-XL and XIAP and phosphorylation activation of the pro-apoptotic protein Bid. Midazolam inhibited growth of HT29 tumors in xenograft mice. Collectively our results demonstrate that midazolam caused growth inhibition of cancer cells via activation of the mitochondrial intrinsic pathway of apoptosis and inhibited HT29 tumor growth in xenograft mice. The mechanism underlying these effects of midazolam might be suppression of ROS production leading to modulation of apoptosis and growth regulatory proteins. These findings present possible clinical implications of midazolam as an anesthetic to relieve pain during in vivo anticancer drug delivery and to enhance anticancer efficacy through its ROS-scavenging and pro-apoptotic properties.

MEL-18 loss mediates estrogen receptor–α downregulation and hormone independence

The polycomb protein MEL-18 has been proposed as a tumor suppressor in breast cancer; however, its functional relevance to the hormonal regulation of breast cancer remains unknown. Here, we demonstrated that MEL-18 loss contributes to the hormone-independent phenotype of breast cancer by modulating hormone receptor expression. In multiple breast cancer cohorts, MEL-18 was markedly downregulated in triple-negative breast cancer (TNBC). MEL-18 expression positively correlated with the expression of luminal markers, including estrogen receptor-α (ER-α, encoded by ESR1). MEL-18 loss was also associated with poor response to antihormonal therapy in ER-α-positive breast cancer. Furthermore, whereas MEL-18 loss in luminal breast cancer cells resulted in the downregulation of expression and activity of ER-α and the progesterone receptor (PR), MEL-18 overexpression restored ER-α expression in TNBC. Consistently, in vivo xenograft experiments demonstrated that MEL-18 loss induces estrogen-independent growth and tamoxifen resistance in luminal breast cancer, and that MEL-18 overexpression confers tamoxifen sensitivity in TNBC. MEL-18 suppressed SUMOylation of the ESR1 transactivators p53 and SP1, thereby driving ESR1 transcription. MEL-18 facilitated the deSUMOylation process by inhibiting BMI-1/RING1B-mediated ubiquitin-proteasomal degradation of SUMO1/sentrin-specific protease 1 (SENP1). These findings demonstrate that MEL-18 is a SUMO-dependent regulator of hormone receptors and suggest MEL-18 expression as a marker for determining the antihormonal therapy response in patients with breast cancer.