• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5753-5757
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• 2012

Apoptosis, also known as cell suicide or programmed cell death, removes unwanted and genetically damaged cells from the body. Evasion of apoptosis is one of the major characteristic features of rapidly proliferating tumor cells. Chemopreventive agents inhibit or suppress tumor formation through apoptotic induction in target tissues. The aim of the present study was to investigate the pro-apoptotic potential of lupeol during 7,12-dimethylbenz(a) anthracene (DMBA) induced hamster buccal pouch carcinogenesis. Topical application of 0.5% DMBA three times a week for 14 weeks in the buccal pouches of golden Syrian hamsters resulted in oral squamous cell carcinoma. The expression pattern of apoptotic markers was analyzed using immunohistochemistry (p53, Bcl-2, Bax) and ELISA reader (caspase 3 and 9). In the present study, 100% tumor formation with defects in apoptotic markerexpression pattern was noticed in hamsters treated with DMBA alone. Oral administration of lupeol at a dose of 50mg/kg bw completely prevented the formation oral tumors as well as decreased the expression p53 and Bcl-2, while increasing the expression of Bax and the activities of caspase 3 and 9. The present study thus indicated that lupeol might inhibit DMBA-induced oral tumor formation through its pro-apoptotic potential in golden Syrian hamsters.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5701-5708
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• 2012

The aim of the study was to investigate the chemopreventive potential of andrographolide in 7,12-dimethylbenz(a) anthracene (DMBA)-induced hamster buccal pouch carcinogenesis. Oral tumors developed in the buccal pouch of golden Syrian hamsters at a 100% incidence on painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks. Marked abnormalities in the status of detoxification enzymes, lipid perxodiation and antioxidants were noticed in hamsters treated with DMBA alone. Oral administration of andrographolide at a dose of 50 mg/kg bw to hamsters treated with DMBA not only completely prevented the tumor formation but also restored the status of the above mentioned biomarkers. The present study thus demonstrates the chemopreventive potential of andrographolide in DMBA-induced hamster buccal pouch carcinogenesis, which is probably due to its antioxidant potential as well as modulating effect on xenobiotic metabolising enzymes during DMBA-induced oral carcinogenesis.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.2087-2092
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• 2015

Nowadays herbal-derived medicines are attracting attention as new sources of drugs with few side effects. Silibinin is a flavonoid compound with chemotheraputic effects on different cancers such as examples in the prostate, lung, colon and breast. In the present study, the cytotoxic effects of silibinin on MCF7 breast cancer cells were investigated. Apoptosis was determined by flow cytometry and the impact of silibinin on the expression of pivotal genes including Bak, P53, P21, BRCA1, BCL-X1 and ATM was analyzed. Treatment for 24h had a significant dose-dependent inhibitory effect on cell growth (p<0.05) with dose- and time- dependent induction of apoptosis (p<0.05). In addition, there were significant increases in BRCA1, ATM, Bak and Bcl-XL gene expression at the mRNA level with different concentrations of silibinin for 24 or 48 h (p<0.05). Taken together, the results suggest that silibinin inhibits the proliferation and induces apoptosis of MCF-7 cells by down-regulating Bak, P53, P21, BRCA1, BCL-Xl and thus may be considered as an effective adjuvant drug to produce a better chemopreventive response for the cancer therapy.

• Korean Journal of Pharmacognosy
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• v.35 no.4 s.139
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• pp.357-363
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• 2004

Flavonoids are class of polyphenolic compounds widely distributed in the plant kingdom, which display a variety of biological activities, including antiviral, antithrombotic, antiiflammatory, antihistaminic, antioxidant and free-radical scavenging abilities. To determined flavonoid, myricetin in the presence of other antioxidants - vitamin C and vitamin E - can exert antioxidative properties not only directly by modulating the AOE system but also scavenging free radical, we investigated cell viability, antioxidant enzyme activities and ROS level in B16F10 murine melanoma cell. B16F10 cells were exposed to medium containing myricetin in the presence or absence of vitamin C or vitamin E for a period of 24 hr. Cell viability was measured by MTT assay. In co-treating myricetin with other antioxidants, CAT activities were increased, compared with control, but SOD and GPx activities were decreased, compared with each antioxidant treated groups . In the group of myricetin or myricetin present with other antioxidants, ROS levels were decreased dose-dependently. Especially, myricetin present of other antioxidants were decreased compared with myricetin.

• Molecular & Cellular Toxicology
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• v.4 no.2
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• pp.93-99
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• 2008

Human cyclin D3 gene (CCND3) located on 6p21.1 is important for the regulation of the G1-S phase transition of the cell cycle by modulating the activity of the cyclin-dependent kinases Cdk4 and Cdk6. Because little is known about the effect of cyclin D3 in various human cancers, we evaluated the intricate relationship between expression of cyclin D3 and the process of HCC development using immunohis tochemistry and TUNEL assay on 43 paraffin embedded tissues. Cyclin D3 immunoreactivity was more frequently observed in the tumors with high histologic grade and the tumors with metastasis, and more frequently expressed in HCCs with cirrhotic background and gain of 6p21.1 when compared with those with non-neoplastic tissue. Apoptotic cells were more common in tumor with cirrhotic background, amplification of 6p21.1 and expression of cyclin D3 when compared with HCCs with lower level of cyclin D3 expression. Also, we observed that some of the cyclin D3 positive cell and apoptotic cell were co-localized. From these results, it is suggested that over-expression of cyclin D3 may contribute to more rapid cell turn-over in the background of HCC, and balance between proliferation and apoptosis is a role in the progression of HCC with cirrhotic background.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.37-42
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• 2012

Improvement of plant growth by Methylotrophic bacteria can be influenced through alterations in growth modulating enzymes or hormones, especially by decreasing ethylene levels enzymatically by 1-aminocyclopropane-1-carboxylate (ACC) deaminase or by production of indole-3-acetic acid (IAA). In this study, the effect of seven strains of Methylobacterium on seedling ethylene emission of tomato and red pepper plants was evaluated under greenhouse condition. Ethylene emission was lowest in Methylobacterium oryzae CBMB20 inoculated tomato plants and CBMB110 inoculated red pepper plants at 47 days after sowing (DAS). However, at 58 DAS all inoculated plants showed almost similar pattern of ethylene emission. Methylobacterium inoculated tomato and red pepper plants showed significantly less ethylene emission compared to control. Our results demonstrated that Methylobacterium spp. inoculation promotes plant growth due to the reduction of ethylene emission and therefore can be potentially used in sustainable agriculture production systems.

• Journal of Plant Biology
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• v.39 no.2
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• pp.113-121
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• 1996

The role of Ca2+ on benzyladenine (BA)-induced senescence retardation in mature wheat (Triticum aestivum L.) primary leaves was investigated. When an extracellular calcium chelator, ethylene glycol-bis-($\beta$-aminoethylether)-N, N'-tetraacetic acid (EGTA) together with BA, was applied to senescing leaves for 4 days of dark incubation, the content of chlorophyll and soluble protein decreased rapidly. And, the content of malondialdehyde (MDA), known to be a degradation product of membrane lipids, increased compared with the BA alone control. The BA-EGTA combination also caused the stimulation of protease and RNase activity and a rapid loss of catalase activity owing to the decling of BA effects. In the case of treatment with only intracellular calcium antagonist 3, 4, 5-trimethoxybenzoic acid 8-(diethylamino) octyl ester (TMB-8) without the BA addition, the chlorophyll content at day 4 after dark incubation decreased in paralled with the increasing concentration of the antagonist. In addition, the chlorophyll content at 10-5 M calcium ionophore A23187 treatment in the absence of BA was similar to that of the BA alone treatment. These results suggest that calcium may mediate the retardation effect of BA on leaf senescence by acting as a second messenger and that the calcium input from cell organelles, as well as the calcium inflow from intercellular spaces and cell walls, may be involved in modulating cytosolic calcium levels related to BA action.

• Biomolecules & Therapeutics
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• v.18 no.4
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• pp.402-410
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• 2010

Although the overproduction of prostaglandin $E_2$ ($PGE_2$) in intestinal epithelial cells has been considered to be highly correlated with the colorectal carcinogenesis, the precise mechanism of action remains poorly elucidated. Accumulating evidence suggests that the PGE receptor (EP)-mediated signal transduction pathway might play an important role in this process. In the present study, we investigated the mechanism of action underlying $PGE_2$-mediated cell proliferation and the effect of resveratrol on the proliferation of human colon cancer cells in terms of the modulating $PGE_2$-mediated signaling pathway. $PGE_2$ stimulated the proliferation of several human colon cancer cells and activated growth-stimulatory signal transduction, including Akt and ERK. $PGE_2$ also increased the phosphorylation of GSK-$3{\beta}$, the translocation of ${\beta}$-catenin into the nucleus, and the expressions of c-myc and cyclin D1. Resveratrol, a cancer chemopreventive phytochemical, however, inhibited $PGE_2$-induced growth stimulation and also suppressed $PGE_2$-mediated signal transduction, as well as ${\beta}$-catenin/T cell factor-mediated transcription in human colon cancer cells. These findings present an additional mechanism through which resveratrol affects the regulation of human colon cancer cell growth.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.133-135
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• 2007

This research presented the new zero-current switching pulse width modulation SEPP(Single Ended Push-Pull)high frequency inverter for solving the problem of the zero-current SEPP high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the zero-current switching pulse width modulation SEPP high frequency inverter. The inverter circuit which is attempted by on-off operation of a switch has the reduction effect of the power loss due to a soft switching and a high frequency switching. And it confirmed that the power regulation is possible continuously from 0.25[kW] until 2.84[kW] in the case the duty rate(D) changes from 0.08 to 0.3 under zero-current switching operating by a dissymmetry pulse width modulating control and the power conversion efficiency comes true the efficiency of 95[%]. Due to the result above, the ZCS PWM SEPP high frequency inverter will be effective as sources of an induction heating apparatus.

• BMB Reports
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• v.32 no.5
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• pp.456-460
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• 1999

The promoter of the HSV-1 VP16 gene contains binding sites for the cellular transcription factors such as USF, CTF, and Sp1, each of which affects basal level expression of the VP16 gene. Transcription of the VP16 gene was induced by viral immediate-early proteins, ICP0 and ICP4, in a synergistic manner but repressed by ICP22. To gain further insight into the role of ICP0 in the expression of the VP16 gene during virus infection, several mutants with deletions in each of their transcriptional regulatory elements were generated. According to transient gene expression assays of these mutants using the CAT gene as a reporter, the USF and CTF binding sites were necessary for efficient induction of the promoter in the presence of transfected ICP0 or during virus infection, whereas the Sp1 binding site had little effect on ICP0-mediated VP16 expression. These results indicate that the immediate early proteins of HSV-1 regulate expression of the VP16 gene during virus infection by modulating the activities of cellular transcription factors such as USF and CTF.