Jiyeon Seo

Suppression of 7,12-dimethylbenz(a)anthracene-induced mammary tumorigenesis by glyceollins.

SCOPE Our previous study showed that glyceollins induced phase 2 detoxifying and antioxidant enzymes. As chemical carcinogens can be detoxified by metabolic activity of phase 2 enzymes, subsequently decreasing their tumorigenic potential, we investigated whether 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumorigenesis could be attenuated by treatment with glyceollins in a mouse model. METHODS AND RESULTS Pretreatment with glyceollins (5 mg/kg body weight) caused a significant reduction in tumor formation and an increase in survival rate. The protective effect of glyceollins against DMBA-induced tumorigenesis was found to be mainly associated with their potential to induce phase 2/antioxidant enzymes that are, in turn, regulated by the nuclear factor E2-related factor 2 signaling pathway, and to a less extent to suppress phase 1 enzymes. As glyceollins increased the number of terminal end buds, a tumor-prone mammary tissue type in mice, it is unlikely that they exert their antitumorigenic action through their estrogenic activity. CONCLUSION Glyceollins were found to have a protective effect in a chemically induced mammary tumor model.

Induction of Anticarcinogenic Enzymes by Dichloromethane-soluble Fraction of Physalis alkekengi var. francheti Hort. in Mouse Hepatoma Cells

Physalis alkekengi var. francheti Hort. is known as an insecticide and traditional remedy for liver related diseases. Therefore, this study investigated the chemopreventive effects of extracts and several solvent fractions (n-hexane, dichloromethane, n-butanol, water) of Physalis alkekengi var. francheti Hort. First, their cytotoxicity and NQO1 activity were measured using an MTT assay, plus a quinone reductase [NAD(P)H dehydrogenase (quinone); NAD(P)H: (quinone acceptor) oxidoreductase, EC 1.6.99.2]-inducing activity assay was performed using cultured murine hepatoma cells (Hepa1c1c7) and its mutant cells(BpRc1). The reduction of electrophilic quinones by NQO1 is an important detoxification pathway and major mechanism of chemoprevention. When compared with the other solvent soluble fractions with different polarities, the dichloromethane fraction of Physalis alkekengi var. francheti Hort. showed a higher NQO1-inducing activity that was also dose-dependent. Moreover, the dichloromethane fraction of Physalis alkekengi var. francheti Hort. induced ARE-luciferase activities in HepG2-C8 cells that were generated by transfecting the ARE-luciferase gene construct, suggesting the Nrf2-ARE-mediated induction of anti-oxidative enzymes. In conclusion, the dichloromethane-soluble fraction of Physalis alkekengi var. francheti Hort. showed a relatively strong induction of detoxifying enzymes, thereby meriting further study to identify the active components and evaluate their potential as cancer preventive agents.

Abstract 4579: Effect of pre-adipocyte and differentiated adipocyte conditioned media on galectin-3 expression in mouse intestinal epithelial cells

We hypothesized that obesity cause inflammation which, in turn, promotes colon carcinogenesis. To test the hypothesis mouse intestinal IEC-6 cells were incubated in the presence of pre-conditioned media collected from culturing LPS-stimulated macrophage, followed by comparing protein expression profile with control cells. Our proteomic study revealed 45 differentially regulated proteins in mouse intestinal IEC-6 cells under state of inflammation. Among others, galectin-3, a beta-galactoside-binding protein, was up-regulated. Galectin-3 has been reported to play anti-apoptotic role in tumor progression and metastasis, and its over-expression has been observed in several types of cancer such as colon cancer. In order to determine relationship between obesity-induced inflammation and colon carcinogenesis, conditioned media (CM) from LPS-stimulated 3T3-L1 pre-adipocytes or differentiated adipocytes were utilized to culture IEC-6 cells. The CM was analyzed for levels of nitric oxide (NO), TNF-α and IL-6, and IEC lysates were analyzed for galectin-3 expression by western blot. Results showed that enhanced generation of NO, TNF-α and IL-6 resulted in upregulation of galectin-3 with respect to incubation time. Also, cytokine concentration was correlated to level of galectin-3, as verified by incubating IEC with increasing concentration of TNF-α or IL-6. These results indicate involvement of pro-inflammatory mediators from pre-adipocytes and adipocytes in colon carcinogenesis, in which galectin-3 may play a crucial role. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4579.

Abstract 5666: Nrf2-mediated induction of phase 2 detoxifying enzymes by an active compound isolated from Chrysanthemum zawadskii

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Previous study demonstrated that methanolic extract of Chrysanthemum has the potential to induce detoxifying enzymes such as NAD(P)H:(quinone acceptor) oxidoreductase 1 (EC [1.6.99.2][1]) (NQO1, QR). In this study we further fractionated methanolic extract of Chrysanthemum and investigated the detoxifying enzyme-inducing potential of each fraction. The fraction shown the highest NQO1-inducing activity was found to contain (+)-(3S,4S,5R,8S)-(E)-8-acetoxy-4-hydroxy-3-isovaleroyloxy-2-(hexa-2,4-diynyliden)-1,6-dioxaspiro[4,5]decane (CZ-5) which increased NQO1 enzyme activity in a dose-dependent manner. And the compound (CZ-5), like most phase 2 enzyme inducers, caused a increasing expression pattern of phase 2 detoxifying enzymes in a dose-dependent manner in mouse hepatoma Hepa1c1c7 and BPRc1 cells. Moreover, CZ-5 caused a dose-dependent enhancement of luciferase activity in HepG2-C8 cells generated by stably transfecting antioxidant response element-luciferase gene construct, suggesting that it induce antioxidant/detoxifying enzymes through antioxidant response element (ARE)-mediated transcriptional activation of the relevant genes. CZ-5 also stimulated nuclear accumulation of Nrf2 as evaluated by western blot analysis. In conclusion, our data showed that CZ-5 acted as a potent phase 2 detoxifying enzyme inducer by stimulating the nuclear accumulation of Nrf2 and had potential as chemopreventive agent Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5666. [1]: pending:yes

Abstract 227: Antitumor activity of glyceollins through induction of apoptosis

Glyceollins, which are synthesized from daidzein in soybean infected with fungi, have been shown to have anti-fungal effects and cancer preventive properties. However, the effects of glyceollins on apoptosis of cancer cell are not well known. We have investigated the antitumor effects of glyceollins on murine hepatoma cell lines. Cell viability was tested with a MTT assay. In Hepa1C1C7, glyceollins markedly reduced cell viability which was due to apoptosis. Glyceollins were observed to induce apoptosis of Hepa1C1C7 cells as evidenced by cell-morphological changes, an early redistribution of plasma membrane phosphatidylserine, increases in membrane leakage (propidium iodide) staining), Annexin-V binding, sub G1 phase in the cell cycle, and DNA laddering. Western blot analysis showed that upon treatment of tumor cells with the glyceollins, cleavage of pro-caspases-3 and significant release of mitochondrial cytochrome c into the cytosol were readily observed. This study demonstrated that glyceollins caused cell death via an apoptotic pathway, which might be exploited for prevention of tumor development. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 227.