• Biomolecules & Therapeutics
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• 제20권2호
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• pp.144-151
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• 2012

The molecular mechanisms by which a variety of naturally-occurring dietary compounds exert chemopreventive effects have been a subject of intense scientific investigations. Induction of phase II detoxification and anti-oxidant enzymes through activation of Nrf2/ARE-dependent gene is recognized as one of the major cellular defense mechanisms against oxidative or xenobiotic stresses and currently represents a critical chemopreventive mechanism of action. In the present review, the functional significance of Keap1/Nrf2 protein module in regulating ARE-dependent phase II detoxification and anti-oxidant gene expression is discussed. The biochemical mechanisms underlying the phosphorylation and expression of Keap1/Nrf2 proteins that are controlled by the intracellular signaling kinases and ubiquitin-mediated E3 ligase system as well as control of nucleocytoplasmic translocation of Nrf2 by its innate nuclear export signal (NES) are described.

• 약학회지
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• 제45권1호
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• pp.101-107
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• 2001

Green tea catechins (GTC) and its major component, (-)-epigallocatechin gallate (EGCG) were studied for their protective effects against reactive oxygen species (ROS)-induced oxidative stress. GTC and EGCG skewed the strong antioxidative effects on the lipid peroxidation of ethyl linolate with Fenton's reagent and free radical scavenging effect to DPPH radical generation. They also protected $H_2O$$_2$- or KO$_2$-induced cytotoxicity in CHL cells or mouse splenocytes. These results indicate that GTC and EGCG are capable of protecting the lipid peroxidation, flee radical generation and cytotoxicity induced by ROS. The mechanism of inhibition in ROS-induced cytotoxicity may be due to their antiofidative and free radical scavenging properties. Therefore, GTC and EGCG may be useful chemopreventive agents by protecting the free radical generation which are involved in cancer and aging.

• 생명과학회지
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• 제17권7호통권87호
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• pp.996-1001
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• 2007

본 연구에서는 NSAID계 약물인 sulindac, sulindac sulfone, 그리고 sulindac sulfide 처리에 의한 암세포 생존율에 미치는 영향을 확인하기 위하여, 인간 대장암 세포주인 HCTl16에 각각 10 ${\mu}M$의 NSAID들을 처리하였다. 처리한약물 중 sulindac sulfide에 의한 암세포 생존율이 가장 높게 감소하는 것으로 MTS assay 결과 확인되었다. 또한 sulindac sulfide의 처리 농도가 증가됨에 따라 세포 생존율이 감소하는 것으로 확인되었다. Sulindac sulfide의 처리에 따른 이러한 암 세포 사멸의 분자생물학적 기전을 이해하기 위하여, oligo DNA microarray 실험을 수행하였다. 그 결과, 10 ${\mu}M$의 sulindac sulfide의 처리에 의해 2배 이상 발현이 증가되는 유전자가 23개 확인되었고, 반대로 2배 이상 발현이 감소되는 유전자가 33개 확인되었다. 증가되는 유전자중 3개(NAG-1, DDIT3, PCK2)를 선택하여, RT-PCR과 real-time PCR을 수행하였다. 그 결과 두 실험 모두 DNA microarray 실험결과와 동일하게 발현이 증가되었다. 이 중 sulindac, sulindac sulfone, sulindac sulfide에 의 한 NAG-1 유전자의 발현변화를 RT-PCR과 real-time PCR 방법으로 확인한 결과, sulindac sulfide에 의한 암 억제유전자인 NAG-1의 발현이 가장 많이 발현되었다. 이러한 연구결과는 세포생존율 결과와 비교하였을 때, NAG-1의 높은 발현과 암 세포 생존율의 감소가 관련이 있음을 간접적으로 시사한다. 따라서 이들 연구결과는 sulindac sulfide에 의한 화학적 암 예방법의 분자생물학적 기전을 이해하는데 도움을 줄 것으로 생각한다.

• Journal of Ginseng Research
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• 제35권3호
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• pp.339-343
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• 2011

Polycyclic aromatic hydrocarbons (PAHs) are well known environmental carcinogens. PAH metabolites, especially BaP-7,8- dihydrodiol, 9,10 epoxide, initiate carcinogenesis via high specificity binding to DNA to form DNA adducts. The Korean red ginseng (KRG) from Panax ginseng has been suggested to protect against damages due to PAH exposure but the mechanism is unknown. Therefore, we investigated effects of KRG on PAH exposure using toxicokinetic methods and changes of PAH-induced oxidative damage during a 2 week-clinical trial (n=21 healthy young female, $23.71{\pm}2.43$ years). To analyze antioxidative effects of KRG, we measured changes in the levels of urinary malondialdehyde (MDA) before and after KRG treatment. We observed a significant positive association between levels of urinary MDA and 1-hydroxypyrene, a biomarker of PAH exposures (slope=1.47, p=0.03) and confirmed oxidative stress induced by PAH exposures. A reverse significant correlation between KRG treatment and level of urinary MDA was observed (p=0.03). In summary, results of our clinical trial study suggest that KRG plays a significant role in antioxidative as well as toxicokinetic pathways against PAHs exposure.

• Asian Pacific Journal of Cancer Prevention
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• 제14권3호
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• pp.1571-1578
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• 2013

Cancer is a leading cause of death worldwide. Recently, the demand for more effective and safer therapeutic agents for the chemoprevention of human cancer has increased. As a white rot fungus, Inonotus obliquus is valued as an edible and medicinal resource. Chemical investigations have shown that I. obliquus produces a diverse range of secondary metabolites, including phenolic compounds, melanins, and lanostane-type triterpenoids. Among these are active components for antioxidant, antitumoral, and antiviral activities and for improving human immunity against infection of pathogenic microbes. Importantly, their anticancer activities have become a hot recently, but with relatively little knowledge of their modes of action. Some compounds extracted from I. obliquus arrest cancer cells in the G0/G1 phase and then induce cell apoptosis or differentiation, whereas some examples directly participate in the cell apoptosis pathway. In other cases, polysaccharides from I. obliquus can indirectly be involved in anticancer processes mainly via stimulating the immune system. Furthermore, the antioxidative ability of I. obliquus extracts can prevent generation of cancer cells. In this review, we highlight recent findings regarding mechanisms underlying the anticancer influence of I. obliquus, to provide a comprehensive landscape view of the actions of this mushroom in preventing cancer.

• Biomolecules & Therapeutics
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• 제24권2호
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• pp.140-146
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• 2016

Naringenin (NAR) as one of the flavonoids observed in grapefruit has been reported to exhibit an anti-cancer activity. Activating transcription factor 3 (ATF3) is associated with apoptosis in human colon cancer cells. This study was performed to investigate the molecular mechanism by which NAR stimulates ATF3 expression and apoptosis in human colon cancer cells. NAR reduced the cell viability and induced an apoptosis in human colon cancer cells. ATF3 overexpression increased NAR-mediated cleaved PARP, while ATF3 knockdown attenuated the cleavage of PARP by NAR. NAR increased ATF3 expression in both protein and mRNA level, and increased the luciferase activity of ATF3 promoter in a dose-dependent manner. The responsible region for ATF3 transcriptional activation by NAR is located between -317 and -148 of ATF3 promoter. p38 inhibition blocked NAR-mediated ATF3 expression, its promoter activation and apoptosis. The results suggest that NAR induces apoptosis through p38-dependent ATF3 activation in human colon cancer cells.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6851-6856
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• 2013

In the present report we determined the protective capacity of grapefruit juice (GJ) against molecular and cellular damage in azoxymethane (AOM) treated mice. Animals were daily administered GJ orally (0.8, 4.1, and 8.2 ${\mu}l/g$) for seven weeks, as well as intraperitoneally (ip) injected with AOM twice (weeks 2 and 3 of the assay). Control groups administered with water, with the high dose of GJ, and with AOM injected in weeks 2 and 3 were also included. The results showed a significant, dose-dependent protection of GJ on the number of colon aberrant crypts (AC) induced by AOM. The highest inhibitory effect was reached with the highest tested dose of GJ, decreasing ACF by 51% and 43% at weeks 4 and 7 of the assay. Regarding protein and lipid oxidation we also found a dose-dependent decrease caused with GJ in comparison with the increased levels produced by AOM. Therefore, our results established chemopreventive potential for GJ, and suggested effects related to its antioxidant capacity. Finally, we found that the tested agents induced neither micronuclei increase nor alteration in bone marrow cytotoxicity.

• Archives of Pharmacal Research
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• 제24권5호
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• pp.441-445
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• 2001

Resveratrol, a trihydroxystilbene found in grapes and several plants, has been shown to be active in inhibiting multistage carcinogenic process. Using resveratrol as the prototype, we synthesized several analogs and evaluated their growth inhibitory effect using cultured human cancer cells. In the present report we show that one of the resveratrol analogs, 3, 5,2',4'-tetramethoxy-trans-stilbene, potentiated the inhibition of cancer cell growth. Prompted by the strong growth Inhibitory activity of the compound ($IC_{50}$; $0.8{\mu}$ g/ml) compared to resveratrol ($IC_{50}$; $18{\mu}$ug/ml) in cultured human colon cancer cells (Col2), we performed an action mechanism study using the compound. The compound induced the accumulation of cellular DNA contents in the sub-CO phase DNA contents of the cell cycle by in a time-dependent manner. The morphological changes were also consistent with an apoptotic process. This result indicated that the compound induced apoptosis of cancer cells, and may be a candidate for use in the development of potential cancer chemotherapeutic or cancer chemopreventive agents.

• 생약학회지
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• 제40권1호
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• pp.77-81
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• 2009

Abies nephrolepis(Pinaceae) extracts were tested for determined immune system regulating activity based on antiinflammatory activity, antioxidant activity and anti-proliferative effect on HeLa cell line. The A. nephrolepis extracts increased dose-dependently anti-proliferation of HeLa cell line. The DM fraction of the extracts having anti-proliferatative effects of HeLa cell line was fractionalized four subfractions($D1{\sim}D4$). Inflammation-induced NO production was inhibited by D2 and D4 in LPS-activated RAW264.7 macrophages. And also, this fractions showed antioxidant activity examined by DPPH radical scavenging effects. These results suggest that the potential use of DM fraction of A. nephrolepis in chemoprevention and regulation overproduction of NO on pathogenic conditions. The mechanism of the inflammatory effects, however, must be evaluated through various parameters in the induction cascade of NO production.

• 한국자원식물학회지
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• 제30권3호
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• pp.265-271
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• 2017

In this study, we elucidated the molecular mechanism of silymarin by which silymarin may inhibits cell proliferation in human colorectal cancer cells in order to search the new potential anti-cancer target associated with the cell growth arrest. Silymarin reduced the level of c-Myc protein but not mRNA level indicating that silymarin-mediated downregulation of c-Myc may result from the proteasomal degradation. In the confirmation of silymarin-mediated c-Myc degradation, MG132 as a proteasome inhibitor attenuated c-Myc degradation by silymarin. In addition, silymarin phosphorylated the threonine-58 (Thr58) of c-Myc and the point mutation of Thr58 to alanine blocked its degradation by silymarin, which indicates that Thr58 phosphorylation may be an important modification for silymarin-mediated c-Myc degradation. We observed that the inhibition of ERK1/2, p38 and $GSK3{\beta}$ blocked the Thr58 phosphorylation and subsequent c-Myc degradation by silymarin. Finally, the point mutation of Thr58 to alanine attenuated silymarin-mediated inhibition of the cell growth. The results suggest that silymarin induces the cell growth arrest through c-Myc proteasomal degradation via ERK1/2, p38 and $GSK3{\beta}-dependent$ Thr58 phosphorylation.