• 식품저장과 가공산업
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• 제7권1호
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• pp.9-18
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• 2008

The health benefits of garlic (Allium sativum L.) are derived from a wide variety of components and from the different ways it is administered. The known health benefits of garlic include cardiovascular protective effects, stimulation of immune function, reduction of blood glucose level, protection against microbial, viral and fungal infections, as well as anticancer effects. In the present study, it was examined the effects of water extract of A. sativum (WEAS) on the growth of cultured human tumor cells in order to investigate its anti-proliferative mechanism. Treatment of WEAS to tumor cells resulted in the growth inhibition, especially in leukemia cells, which was associated with induction of G2/M arrest of the cell cycle and apoptosis. In order to further explore the critical events leading to apoptosis in WEAS-treated U937 human leukemia cells, the following effects of WEAS on components of the mitochondrial apoptotic pathway were examined: generation of reactive oxygen species (ROS), alteration of the mitochondrial membrane potential (MMP), and the expression changes of Bcl-2 and IAP family proteins. The cytotoxic effect of WEAS was mediated by its induction of apoptosis as characterized by the occurrence of DNA ladders, apoptotic bodies and chromosome condensation in U937 cells. The WEAS-induced apoptosis in U937 cells was correlated with the generation of intracellular ROS, collapse of MMP, activation of caspase-3 and down-regulation of anti-apoptotic proteins. The quenching of ROS generation with antioxidant N-acetyl-L-cysteine conferred significant protection against WEAS-elicited ROS generation, caspase-3 activation, G2/M arrest and apoptosis. In conclusion, the present study reveals that the cellular ROS generation plays a pivotal role in the initiation of WEAS-triggered apoptotic death in U937 cells.

• International Journal of Industrial Entomology and Biomaterials
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• 제43권2호
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• pp.94-98
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• 2021

Reactive oxygen species (ROS) induce a variety of cellular responses, such as proliferation, differentiation, senescence, and apoptosis. Intestinal epithelial cells are continuously exposed to ROS, and excessive generation of ROS severely damages cells via oxidative stress. Pro-inflammatory cytokines may lead to intestinal inflammation and damage by inducing excessive ROS generation. In this study, we showed that papiliocin, an antimicrobial peptide, significantly inhibited ROS production, without affecting cell viability. Moreover, TNF-α and IL-6 expression was decreased in the intestinal epithelial cells. The activity of papiliocin may significantly contribute to preserving the integrity of the intestinal mucosa against oxidative damage and inflammation-related disorders.

• Biomolecules & Therapeutics
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• 제14권3호
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• pp.137-142
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• 2006

Apigenin, a natural flavonoid found in a variety of vegetables and fruits, has been shown to possess many biological functions. In this study we investigated the role of apigenin in the production of reactive oxygen species (ROS) through the modulation of activity of $K^+-Cl^-$-cotransport (KCC) in IMR-32 human neuroblastoma cells. Apigenin induced $Cl^-$-dependent $K^+$ efflux, a hallmark of KCC activity, which was markedly prevented by different kinds of KCC inhibitors (calyculin-A, genistein and $BaCl_2$). These results indicate that KCC is functionally present, and activated by apigenin in the IMR-32 cells. Treatment with apigenin also induced a sustained increase in the level of intracellular ROS. The KCC inhibitors also significantly inhibited the apigenin-induced ROS generation. Taken together, these results suggest that apigenin can modulate ROS generation through the activation of a membrane ion transporter, KCC. These results further suggest that the alteration of KCC activity may play a role in the mechanism of degenerative diseases and/or carcinogenesis in neuronal tissues through the regulation of ROS production.

• Asian Pacific Journal of Cancer Prevention
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• 제14권2호
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• pp.895-901
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• 2013

Resistance to induction of apoptosis is a major obstacle for bladder cancer treatment. Bcl-2 is thought to be involved in anti-apoptotic signaling. In this study, we investigated the effect of Bcl-2 overexpression on apoptotic resistance and intracellular reactive oxygen species (ROS) generation in bladder cancer cells. A stable Bcl-2 overexpression cell line, BIU87-Bcl-2, was constructed from human bladder cancer cell line BIU87 by transfecting recombinant Bcl-2 [pcDNA3.1(+)-Bcl-2]. The sensitivity of transfected cells to adriamycin (ADR) was assessed by MTT assay. Apoptosis was examined by flow cytometry and acridine orange fluorescence staining. Intracellular ROS was determined using flow cytometry, and the activities of superoxide dismutase (SOD) and catalase (CAT) were also investigated by the xanthinoxidase and visible radiation methods using SOD and CAT detection kits. The susceptibility of BIU87-Bcl-2 cells to ADR treatment was significantly decreased as compared with control BIU87 cells. Enhanced expression of Bcl-2 inhibited intracellular ROS generation following ADR treatment. Moreover, the suppression of SOD and CAT activity induced by ADR treatment was blocked in the BIU87-Bcl-2 case but not in their parental cells. The overexpression of Bcl-2 renders human bladder cancer cells resistant to ADR-induced apoptosis and ROS might act as an important secondary messenger in this process.

• Mycobiology
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• 제44권1호
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• pp.38-47
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• 2016

The ascomycete fungus Mycosphaerella graminicola (synonym Zymoseptoria tritici) is an important pathogen of wheat causing economically significant losses. The primary nutritional mode of this fungus is thought to be hemibiotrophic. This pathogenic lifestyle is associated with an early biotrophic stage of nutrient uptake followed by a necrotrophic stage aided possibly by production of a toxin or reactive oxygen species (ROS). In many other fungi, the genes CREA and AREA are important during the biotrophic stage of infection, while the NOXa gene product is important during necrotrophic growth. To test the hypothesis that these genes are important for pathogenicity of M. graminicola, we employed an over-expression strategy for the selected target genes CREA, AREA, and NOXa, which might function as regulators of nutrient acquisition or ROS generation. Increased expressions of CREA, AREA, and NOXa in M. graminicola were confirmed via quantitative real-time PCR and strains were subsequently assayed for pathogenicity. Among them, the NOXa over-expression strain, NO2, resulted in significantly increased virulence. Moreover, instead of the usual filamentous growth, we observed a predominance of yeast-like growth of NO2 which was correlated with ROS production. Our data indicate that ROS generation via NOXa is important to pathogenicity as well as development in M. graminicola.

• 생명과학회지
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• 제25권2호
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• pp.231-236
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• 2015

Angiotensin II (AngII)는 혈관평활근세포의 수축을 통해 혈관을 수축시키는 강력한 작용을 나타낼 뿐만 아니라 혈관세포의 성장 등에 중요한 역할을 한다. 본 연구에서는 AngII에 의해 형성되는 활성산소가 phosphatidylinositol 3-kinase (PI3K)에 유리되는 칼슘에 의해 조절된다는 것을 검증하였다. 쥐의 대동맥으로부터 분리된 혈관평활근세포에서 AngII에 의해 활성산소가 농도 의존적, 그리고 시간 의존적으로 형성됨을 관찰하였다. AngII에 의해 형성되는 활성산소는 PI3K의 억제제에 의해 봉쇄되었으나 EKR의 억제제에 의해서는 봉쇄되지 않음을 알 수 있었다. AngII에 의해 유리되는 칼슘은 L-type 칼슘이온통로 봉쇄제인 Nifedipine 또는 배양액에 칼슘이 제거된 환경에서 억제됨을 확인할 수 있었다. 마지막으로 AngII에 의해 형성되는 활성산소는 배양액에 칼슘이 없는 조건이나 L-type 칼슘이온통로 억제제를 전처리 하였을 경우 억제되는 것을 확인하였다. 이러한 결과들을 바탕으로 쥐의 대동맥으로부터 분리된 혈관평활근세포에서 AngII에 의한 활성산소의 형성은 PI3K/L-type 칼슘이온통로를 통한 기전을 통해 조절됨을 제안한다.

• The Korean Journal of Physiology and Pharmacology
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• 제6권4호
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• pp.187-191
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• 2002

Tamoxifen, an antiestrogen, has previously been shown to induce apoptosis in HepG2 human hepatoblastoma cells through activation of the pathways independent of estrogen receptors, i.e., intracellular $Ca^{2+}$ increase and generation of reactive oxygen species (ROS). However, the mechanism of tamoxifen to link increased intracellular $Ca^{2+}$ to ROS generation is currently unknown. Thus, in this study we investigated the possible involvement of calmodulin, a $Ca^{2+}$ activated protein, and $Ca^{2+}$/calmodulin-dependent protein kinase II in the above tamoxifen-induced events. Treatment with calmodulin antagonists (calmidazolium and trifluoroperazine) or specific inhibitors of $Ca^{2+}$/calmodulin-dependent protein kinase II (KN-93 and KN-62) inhibited the tamoxifen-induced apoptosis in a dose-dependent manner. In addition, these agents blocked the tamoxifen-induced ROS generation in a concentration-dependent fashion, which was completely suppressed by intracellular $Ca^{2+}$ chelation. These results demonstrate for the first time that, despite of its well-known direct calmodulin-inhibitory activity, tamoxifen may generate ROS and induce apoptosis through indirect activation of calmodulin and $Ca^{2+}$/calmodulin-dependent protein kinase II in HepG2 cells.

• Parasites, Hosts and Diseases
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• 제53권5호
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• pp.597-603
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• 2015

Trichomonas vaginalis is a flagellated protozoan parasite that causes vaginitis and cervicitis in women and asymptomatic urethritis and prostatitis in men. Mast cells have been reported to be predominant in vaginal smears and vaginal walls of patients infected with T. vaginalis. Mitogen-activated protein kinase (MAPK), activated by various stimuli, have been shown to regulate the transcriptional activity of various cytokine genes in mast cells. In this study, we investigated whether MAPK is involved in ROS generation and exocytotic degranulation in HMC-1 cells induced by T. vaginalis-derived secretory products (TvSP). We found that TvSP induces the activation of MAPK and NADPH oxidase in HMC-1 cells. Stimulation with TvSP induced phosphorylation of MAPK and $p47^{phox}$ in HMC-1 cells. Stimulation with TvSP also induced up-regulation of CD63, a marker for exocytosis, along the surfaces of human mast cells. Pretreatment with MAPK inhibitors strongly inhibited TvSP-induced ROS generation and exocytotic degranulation. Finally, our results suggest that TvSP induces intracellular ROS generation and exocytotic degranulation in HMC-1 via MAPK signaling.

• 대한임상검사과학회지
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• 제45권3호
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• pp.114-119
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• 2013

Potassium is essential for the proper functioning of the ears. The inner ear's endolymph differs from all other extracellular fluids (in its positive potential) and in the ionic compositions in the various parts of the endolymphatic space. Ion concentration of the endolymph is 150 mM of potassium, which is comparable to the concentrations in other organs. Cisplatin (cis-diamminedichloroplatinum II: CDDP) is one of the most effective anticancer drugs, widely used against various tumors. However, its clinical use is limited by the onset of severe side effects, including ototoxicity and nephrotoxicity. For ototoxicity, a number of evidences in cytotoxic mechanism of cisplatin, including perturbation of redox status, increase in lipid peroxydation, and formation of DNA adduct, have been suggested. Therefore, in this study, the author investigated the relationship between the potassium ions on cisplatin-induced cytotoxicity in HEI-OC1 cells associated with reactive oxygen species (ROS). KCNE1 gene expression by the concentration of intracellular potassium appeared in the plasma membrane and increased the concentration of intracellular potassium. Cisplatin decreased the viability of HEI-OC1 cells, but the KCNE1 gene increased. Also, the KCNE1 gene significantly suppressed generation of intracellular ROS by cisplatin. Western blot analysis showed that the KCNE1 gene increased phase II detoxification enzymes markers such as superoxide dismutase 1 (SOD1), superoxide dismutase (SOD2), NAD(P)H:quinine oxidoreductases (NQO1), which were associated with the scavenger of ROS. These results suggest that the KCNE1 gene for intracellular potassium concentration ultimately prevents ROS generation from cisplatin and further contributes to protect auditory sensory hair cells from ROS produced by cisplatin.

• 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.