• Journal of Life Science
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• v.25 no.11
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• pp.1331-1337
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• 2015

S-allylcysteine (SAC) is an aged garlic derived water soluble organosulfur compound and has been suggested to have anticarcinogenic activity against diverse types of cancer cells. This review summarizes the cellular signaling pathways and molecular mechanisms whereby SAC exerts its effects on cellular proliferation, apoptosis, cell cycle progression and metastasis based on the results from both in vitro and in vivo studies. SAC activates proapoptotic proteins including Bax and caspase-3, but suppresses antiapoptotic Bcl-2 family proteins to bring about cancer cell death through mitochondria-mediated intrinsic pathway. SAC also inhibits cellular proliferation by inducing cell cycle arrest in which SAC reduces expression and activation of NF-κB, cyclins, Cdks, PCNA and c-Jun, but elevates expression of cell cycle inhibitor proteins p16 and p21 through suppression of both PI3K/Akt/mTOR and MAPK/ERK signaling pathways. And, SAC inhibits invasion and metastasis of cancer cells by inducing suppression of both angiogenesis and epithelial-mesenchymal transition (EMT) through decreased cyclooxygenase (COX)-2 expression and increased E-cadherin expression which were then caused by suppression of inhibitory transcription factors Id-1 and SLUG from SAC-mediated inactivation of both MAPK/ERK and PI3K/Akt/mTOR/NF-κB signaling pathways. Furthermore, SAC prevents toxic compound-induced carcinogenesis by inducing antioxidant enzymes such as glutathione-s-transferase (GST). Thus, SAC can be considered as a potential chemotherapeutic agent for the prevention and treatment of cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3447-3450
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• 2015

Objective: To explore the sensitivity of gastric cancer cells to chemotherapy drugs in elderly patients and its correlation with cyclooxygenase-2 (COX-2) expression in cancer tissue. Materials and Methods: Forty-three elderly patients with gastric cancer (observation group) and 31 young patients with gastrointestinal tumors (control group) who were all diagnosed by pathology and underwent surgery in the 89th Hospital of Chinese People's Liberation Army were selected. Drug sensitivity testing of tumor cells in primary culture was carried out in both groups using a methyl thiazolyl tetrazolium (MTT) method, and the expression of COX-2 and the factors related to multi-drug resistance (MDR) in cancer tissue were assessed by immunohistochemistry. Results: The inhibition rates (IR) of vincristine (VCR), 5-fluorouracil (5-FU), oxaliplatin (L-OHP), mitomycin (MMC) and epirubicin (eADM) on tumor cells in the observation group were dramatically lower than in the control group, with statistical significance (P<0.05 or P<0.01). The positive rates of COX-2, glutathione s-transferase-${\pi}$ (GST-${\pi}$) and P glycoprotein (P-gp) expression in cancer tissue in the observation group were all higher than in control group (P<0.05), while that of DNA topoisomerase $II{\alpha}$ ($TopoII{\alpha}$) expression lower than in the control group (P<0.01). In the observation group, COX-2 expression in cancer tissue had a significantly-positive correlation with GST-${\pi}$ and P-gp (r=0.855, P=0.000; r=0.240, P=0.026), but a negative correlation with $TopoII{\alpha}$ (r=-0.328, P=0.002). In the control group, COX-2 expression in cancer tissue was only correlated with P-gp positively (r=0.320, P=0.011). Bivariate correlation analysis displayed that COX-2 expression in cancer tissue in the observation group had a significantly-negative correlation with the IRs of 5-FU, L-OHP, paclitaxel (PTX) and eADM in tumor cells (r=-0.723, P=0.000; r=-0.570, P=0.000; r=-0.919, P=0.000; r=-0.781, P=0.000), but with hydroxycamptothecine (HCPT), VCR and 5-FU in the control group (r=-0.915, P=0.000; r=-0.890, P=0.000; r=-0.949, P=0.000). Conclusions: Gastric cancer cells in elderly patients feature stronger MDR, which may be related to high COX-2 expression.

• Archives of Pharmacal Research
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• v.27 no.7
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• pp.757-762
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• 2004

The protective adaptive response to electrophiles and reactive oxygen species is mediated by the induction of phase II detoxifying genes including glutathione S-transferases (GSTs). NF-E2-related factor-2 (Nrf2) phosphorylation by protein kinase C (PKC) is a critical event for its nuclear translocation in response to oxidative stress. Previously, we have shown that peroxynitrite plays a role in activation of Nrf2 and Nrf2 binding to the antioxidant response element (ARE) via the pathway of phosphatidylinositol 3-kinase (PI3-kinase) and that nitric oxide synthase in hepatocytes is required for GSTA2 induction. In view of the importance of PKC and Pl3-kinase in Nrf2-mediated GST induction, we investigated the role of these kinases in peroxynitrite formation for GSTA2 induction by oxidative stress and determined the relationship between PKC and PI3-kinase. Although PKC activation by phorbol 12-myristate-13-acetate (PMA) did not increase the extents of constitutive and inducible GSTA2 expression, either PKC depletion by PMA or PKC inhibition by staurosporine significantly inhibited GSTA2 induction by tert-butylhydroquinone (t-SHa) a prooxidant chemical. Therefore, the basal PKC activity is req- uisite for GSTA2 induction. 3-Morpholinosydnonimine (SIN-1), which decomposes and yields peroxynitrite, induced GSTA2, which was not inhibited by PKC depletion, but slightly enhanced by PKC activation, suggesting that PKC promotes peroxynitrite formation for Nrf2-mediated GSTA2 induction. Treatment of cells with S-nitroso-N-acetyl-penicillamine (SNAP), an exogenous NO donor, in combination with t-BHQ may produce peroxynitrite. GSTA2 induction by SNAP ＋ t-BHQ was not decreased by PKC depletion, but rather enhanced by PKC activation, showing that the activity of PKC might be required for peroxynitrite formation. LY294002 a P13-kinase inhibitor blocked GSTA2 induction by t-BHQ, which was reversed by PMA-induced PKC activation. These results provide evidence that PKC may playa role in formation of peroxynitrite that activates Nrf2 for GSTA2 induction and that PKC may serve an activator for GSTA2 induction downstream of PI3-kinase.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.6135-6140
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• 2013

Background: Breast cancer is a common malignant tumor which affects health of women and multidrug resistance (MDR) is one of the main factors leading to failure of chemotherapy. This study was conducted to establish paclitaxel-resistant breast cancer cell line and nude mice models to explore underlying mechanisms of MDR. Methods: The breast cancer drug-sensitive cell line MCF-7 (MCF-7/S) was exposed in stepwise escalating paclitaxel (TAX) to induce a resistant cell line MCF-7/TAX. Cell sensitivity to drugs and growth curves were measured by MTT assay. Changes of cell morphology and ultrastructure were examined by optical and electron microscopy. The cell cycle distribution was determined by flow cytometry. Furthermore, expression of proteins related to breast cancer occurrence and MDR was tested by immunocytochemistry. In Vivo, nude mice were injected with MCF-7/S and MCF-7/TAX cells and weights and tumor sizes were observed after paclitaxel treatment. In addition, proteins involved breast cancer and MDR were detected by immunohistochemistry. Results: Compared to MCF-7/S, MCF-7/TAX cells had a higher resistance to paclitaxel, cross-resistance and prolonged doubling time. Moreover, MCF-7/TAX showed obvious alterations of ultrastructure. Estrogen receptor (ER) expression was low in drug resistant cells and tumors while expression of human epidermal growth factor receptor 2 (HER2) and Ki-67 was up-regulated. P-glycoprotein (P-gp), lung resistance-related protein (LRP) and glutathione-S-transferase-${\pi}$ (GST-${\pi}$) involved in the MDR phenotype of resistant cells and tumors were all overexpressed. Conclusion: The underlying MDR mechanism of breast cancer may involve increased expression of P-gp, LRP and GST-${\pi}$.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.452-462
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• 2021

Pretilachlor (PRE) is a common acetanilide herbicide used worldwide. However, its effects on aquatic organisms, particularly marine photosynthetic life, are not sufficiently known. Herein, we evaluated the toxic effects of PRE by physiological and molecular parameters in the photosynthetic dinoflagellate Prorocentrum minimum. The cell density, pigment content, and photosynthetic parameters (F_v/F_m and PI_ABS) were considerably decreased with increased PRE exposure time and doses. In addition, photosynthesis-related genes, PmpsbA, PmpsaA, and PmatpB, were significantly upregulated when exposed to 1.0 mg L^-1 of PRE for 24 h (p<0.001). In 72 h treatment, the relative gene expression was significantly increased (0.1 and 0.5 mg L^-1; p<0.01). In contrast, PmrbcL was decreased or little changed compared to the controls. Reactive oxygen species (ROS) increased after 24 h exposure (p<0.001). However, the transcriptional fold-changes in glutathione S-transferase (GST) were significantly increased (0.5 and 1.0 mg L^-1; p<0.001) at 72 h. These findings suggested that the PmGST might be involved in PRE detoxification in P. minimum. In addition, PRE may affect the photosystem function in phytoplankton similar to other acetanilides, causing severe damage or cell death.

• BMB Reports
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• v.34 no.6
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• pp.537-543
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• 2001

In the present study, an in vitro ELISA system to assess the interaction between Src homology (SH)2 domains and phosphotyrosine that contain peptides was established using purified GST-conjugated SH2 proteins and synthetic biotinylated phosphotyrosine that contain oligopeptides. The SH2 domains bound the relevant phosphopeptides that were immobilized in the streptavidin-coated microtiter plate in a highly specific and dose-dependent manner. The epidermal growth factor receptor (EGFR)-, T antigen (T Ag)-, and platelet-derived growth factor receptor (PDGFR)-derived phosphopeptides interacted with the growth factor receptor binding protein (Grb)2/SH2, Lck/SH2, and phosphatidyl inositol 3-kinase (PI3K) p85/SH2, respectively. No cross-reactions were observed. Competitive inhibition experiments showed that a short phosphopeptide of only four amino acids was long enough to determine the binding specificity. Optimal concentrations of the GST-SH2 fusion protein and phosphopeptide in this new ELISA system for screening the binding blockers were chosen at 2nM and 500nM, respectively. When two candidate compounds were tested in our ELISA system, they specifically inhibited the Lck/SH2 and/or p85/SH2 binding to the relevant phosphopeptides. Our results indicate that this ELISA system could be used as an easy screening method for the discovery of specific binding blockers of protein-protein interactions via SH2 domains.

• Environmental Mutagens and Carcinogens
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• v.19 no.1
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• pp.46-55
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• 1999

To develop a chemopreventive strategy based on the different stages of premalignant lesions, we hypothesized that the inhibitory effect of chemopreventive agents is influenced by different promotion stages during carcinogenesis. DMBA-TPA-induced skin carcinogenesis was used with ICR mice and chlorophyllin (CHL) was applied as a chemopreventive agent. In vitro assay was performed with Salmonella typhi. TA100 to observe any anti-mutagenic activity of CHL against DMBA. Pre-initiation and pre-promotion effects of CHL were observed by CHL treatment before initiation and before promotion. To evaluate the inhibitory effect at different promotion stages, each group was divided into three subgroups after TPA promotion for 6, 18 and 24 weeks, respectively ; the first subgroup was immediately sacrificed after termination of TPA, the second subgroup was treated with CHL, and the third subgroup was sacrificed 8 weeks after termination of TPA without CHL treatment. The degrees of epithelial dysplasia, papilloma formation, and invasive carcinoma were observed histologically, and GST-Pi expression was observed immunohistochemically. ODC mRNA level was analyzed by reverse transcriptase-polymerase chain reaction. Results showed : CHL dose-dependently inhibited the mutation of Salmonella typhi. TA100; the incidence of epithelial dysplasia and papilloma formation was lower in pre-initiation and pre-promotion CHL-treated mice than DMBA-TPA-treated mice; no invasive carcinoma developed in pre-initiation CHL-treated groups, while 67% of DMBA-TPA treated mice had carcinomas; GST-Pi expression decreased when CHL was treated before initiation and before promotion; and when CHL was treated after termination of TPA application at 18 and 24- week-TPA promotion stages, respectively, the incidence of epithelial dysplasia and papilloma was markedly reduced compared to non-treated groups. When comparing the incidence of epithelial dysplasia and papilloma between the immediately-sacrificed subgroup and the non-treated group with a waiting period, we speculated that the 18-week-TPA promotion stage might belong to the promoter-independent progression stage. At the 18-week-TPA promotion stage, the level of ODC mRNA in the CHL-treated group was clearly reduced to the level of normal tissue. Taking these results together, CHL showed both anti-initiation and anti-promotion effects, while the inhibitory effect of CHL was prominent in the 18-week-TPA promotion stage. However, CHL seems to be incapable of completely blocking the progression in the 24-week-TPA promotion stage.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.851-857
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• 2000

The activities of phase II and antioxidant enzymes in the liver, lung, kidney, stomach, and colon of mice were examined following intragastric application of polysaccharides extracted from soybeans fermented with either Agrocybe Cylindracea (AC) or Phellinus ignarius (PI). The intragastric application of the extracts to mice for 14 days significantly increased the activities of quinone reductase (QP) and glutathione S-transferase (GST) in the liver and kidney, glutathione (GSH) and superoxide dismutase (SOD) in the liver, kidney, lung, and stomach, and glutathione peroxidase (GSH-Px) in the liver, lung, and kidney. In general, the elevation of the phase II and antioxidant enzymes activities was more pronounced in the liver and kidney as compared to the lung, stomach, and colon. Accordingly, these finding suggest that polysaccharides extracted from soybeans fermented with A. cylindracea or P. igniarius have a cancer chemopreventive potential in various target organs.

• BMB Reports
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• v.37 no.6
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• pp.741-748
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• 2004

The hepatitis C virus is associated with the development of liver cirrhosis and hepatocellular carcinomas. Among the 10 polyproteins produced by the virus, no function has been clearly assigned to the non-structural 5A (NS5A) protein. This study was designed to identify the hepatocellular proteins that interact with NS5A of the HCV. Yeast two-hybrid experiments were performed with a human liver cDNA prey-library, using five different NS5A derivatives as baits, the full-length NS5A (NS5A-F, amino acid (aa) 1~447) and its four different derivatives, denoted as NS5A-A (aa 1~150), -B (aa 1~300), -C (aa 300~447) and D (aa 150~447). NS5A-F, NS5A-B and NS5A-C gave two, two and 10 candidate clones, respectively, including an AHNAK-related protein, the secreted frizzled-related protein 4 (SFRP4), the N-myc downstream regulated gene 1 (NDRG1), the cellular retinoic acid binding protein 1 (CRABP-1), ferritin heavy chain (FTH1), translokin, tumor-associated calcium signal transducer 2 (TACSTD2), phosphatidylinositol 4-kinase (PI4K) and $centaurin{\delta}$ 2 ($CENT{\delta}2$). However, NS5A-A produced no candidates and NS5A-D was not suitable as bait due to transcriptional activity. Based on an in vitro binding assay, CRABP-1, PI4K, $CENT{\delta}2$ and two unknown fusion proteins with maltose binding protein (MBP), were confirmed to interact with the glutathione S-transferase (GST)/NS5A fusion protein. Furthermore, the interactions of CRABP-1, PI4K and $CENT{\delta}2$ were not related to the PXXP motif (class II), as judged by a domain analysis. While their biological relevance is under investigation, the results contribute to a better understanding of the possible role of NS5A in hepatocellular signaling pathways.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4413-4416
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• 2012

Aim: Individual differences in chemosensitivity and clinical outcome in non-small cell lung cancer (NSCLC) patients treatment with platinum-based chemotherapy may be due to genetic factors. Our study aimed to investigate the prognostic role of GSTP1, XRCC1 and XRCC3 in NSCLC patients treated with chemotherapy. Methods: A total of 460 cases were consecutively selected from The Affiliated Hospital of Nantong University between Jan. 2003 to Nov. 2006, and all were followed-up until Nov. 2011. Genotyping of GSTP1 Ile105Val, XRCC1 Arg194Trp, XRCC1 Arg399Gln and XRCC3 Thr241Met was conducted by duplex polymerase-chain-reaction with confronting-two-pair primer methods. Results: Patients with GSTP Val/Val exhibited a shorter survival time, and had a 1.89 fold greater risk of death than did those with the IIe/IIe genotype. For XRCC1 Arg194Trp, the variant genotype Trp/Trp was significantly associated with a decreased risk of death from NSCLC when compared with the Arg/Arg. Individuals carrying XRCC1 399Gln/Gln genotype had a longer survival time, with a lowered risk of death from NSCLC. Conclusion: This study indicated that GSTP1 Ile105Val, XRCC1 Arg194Trp and XRCC1Arg399Gln genes have a role in modifying the effect of platinum-based chemotherapy for NSCLC patients in a Chinese population. Our findings provide information for therapeutic decisions for individualized therapy in NSCLC cases.