• Molecules and Cells
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• 제47권1호
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• pp.100006.1-100006.10
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• 2024

Nitric oxide (NO) serves as an evolutionarily conserved signaling molecule that plays an important role in a wide variety of cellular processes. Extensive studies in Drosophila melanogaster have revealed that NO signaling is required for development, physiology, and stress responses in many different types of cells. In neuronal cells, multiple NO signaling pathways appear to operate in different combinations to regulate learning and memory formation, synaptic transmission, selective synaptic connections, axon degeneration, and axon regrowth. During organ development, elevated NO signaling suppresses cell cycle progression, whereas downregulated NO leads to an increase in larval body size via modulation of hormone signaling. The most striking feature of the Drosophila NO synthase is that various stressors, such as neuropeptides, aberrant proteins, hypoxia, bacterial infection, and mechanical injury, can activate Drosophila NO synthase, initially regulating cellular physiology to enable cells to survive. However, under severe stress or pathophysiological conditions, high levels of NO promote regulated cell death and the development of neurodegenerative diseases. In this review, I highlight and discuss the current understanding of molecular mechanisms by which NO signaling regulates distinct cellular functions and behaviors.

• The Korean Journal of Physiology and Pharmacology
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• 제27권3호
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• pp.277-287
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• 2023

Actin dynamics play an essential role in myogenesis through multiple mechanisms, such as mechanotransduction, cell proliferation, and myogenic differentiation. Twinfilin-1 (TWF1), an actin-depolymerizing protein, is known to be required for the myogenic differentiation of progenitor cells. However, the mechanisms by which they epigenetically regulate TWF1 by microRNAs under muscle wasting conditions related to obesity are almost unknown. Here, we investigated the role of miR-103-3p in TWF1 expression, actin filament modulation, proliferation, and myogenic differentiation of progenitor cells. Palmitic acid, the most abundant saturated fatty acid (SFA) in the diet, reduced TWF1 expression and impeded myogenic differentiation of C2C12 myoblasts, while elevating miR-103-3p levels in myoblasts. Interestingly, miR-103-3p inhibited TWF1 expression by directly targeting its 3'UTR. Furthermore, ectopic expression of miR-103-3p reduced the expression of myogenic factors, i.e., MyoD and MyoG, and subsequently impaired myoblast differentiation. We demonstrated that miR-103-3p induction increased filamentous actin (F-actin) and facilitated the nuclear translocation of Yes-associated protein 1 (YAP1), thereby stimulating cell cycle progression and cell proliferation. Hence, this study suggests that epigenetic suppression of TWF1 by SFA-inducible miR-103-3p impairs myogenesis by enhancing the cell proliferation triggered by F-actin/YAP1.

• 한국식품영양학회지
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• 제25권1호
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• pp.64-68
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• 2012

It has been suggested that Helicobacter pylori(H. pylori) infections can promote the development and progression of gastric cancer through the modulation of cell cycle regulators such as $p27^{Kip1}$ and Skp2. $p27^{Kip1}$ is a cyclin-dependent kinase (CDK) inhibitor that blocks the G1/S transition necessary for cell cycle progression. Skp2 is a component of the ubiquitin ligase complex called $SCF^{Skp2}$(SKP1-Cullin-F-box), which specifically binds and promotes the degradation of $p27^{Kip1}$. A low level of $p27^{Kip1}$ and a high level of Skp2 have been reported in many types of cancers, including gastric cancer. In addition, a decrease in $p27^{Kip1}$ has been reported in H. pylori-infected specimens. However, data on Skp2 in H. pylori infections are limited. This study examines the changes in the status of Skp2 in H. pylori-infected gastric epithelial AGS cells. For this, we stimulated AGS cells with H. pylori(NCTC 11637) at the ratio of 300:1(bacterium:cell) for 6 hours. The results of an immunoprecipitation analysis, followed by a western blot, indicate that the interaction between Skp2 and 14-3-3 was elevated 3 hours after the H. pylori treatment. In addition, there was an increase in cytoplasmic Skp2 after 3 hours, whereas there was no change in the nuclear level. Since it has been reported that interaction with 14-3-3 and the subsequent cytoplasmic translocation of Skp2 can increase its protein stability, increases in the interaction with 14-3-3 and the cytoplasmic Skp2 after the H. pylori treatment can increase the level of Skp2 in AGS cells. This phenomenon may explain, at least to some extent, the mechanism underlying the relationship between H. pylori infections and gastric carcinogenesis.

• Biomolecules & Therapeutics
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• 제27권3호
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• pp.283-289
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• 2019

Brain aging induces neuropsychological changes, such as decreased memory capacity, language ability, and attention; and is also associated with neurodegenerative diseases. However, most of the studies on brain aging are focused on neurons, while senescence in astrocytes has received less attention. Astrocytes constitute the majority of cell types in the brain and perform various functions in the brain such as supporting brain structures, regulating blood-brain barrier permeability, transmitter uptake and regulation, and immunity modulation. Recent studies have shown that SIRT1 and SIRT2 play certain roles in cellular senescence in peripheral systems. Both SIRT1 and SIRT2 inhibitors delay tumor growth in vivo without significant general toxicity. In this study, we investigated the role of tenovin-1, an inhibitor of SIRT1 and SIRT2, on rat primary astrocytes where we observed senescence and other functional changes. Cellular senescence usually is characterized by irreversible cell cycle arrest and induces senescence- associated ${\beta}$-galactosidase (SA-${\beta}$-gal) activity. Tenovin-1-treated astrocytes showed increased SA-${\beta}$-gal-positive cell number, senescence-associated secretory phenotypes, including IL-6 and IL-$1{\beta}$, and cell cycle-related proteins like phospho-histone H3 and CDK2. Along with the molecular changes, tenovin-1 impaired the wound-healing activity of cultured primary astrocytes. These data suggest that tenovin-1 can induce cellular senescence in astrocytes possibly by inhibiting SIRT1 and SIRT2, which may play particular roles in brain aging and neurodegenerative conditions.

• 생명과학회지
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• 제16권7호
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• pp.1235-1242
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• 2006

브로콜리를 포함한 십자화과 식물에서 glucoraphanin의 가수분해를 통해 생성되는 isothiocyanate의 일종인 sulforaphane은 역학적 조사를 포함한 다양한 선행 연구에서 강력한 암예방 효과를 가지는 것으로 알려져 있다. 항암효과에 관한 최근 연구 결과에 따르면 sulforaphane은 다양한 인체암세포의 증식을 억제하고 apoptosis를 유발할 수 있는 것으로 알려지고 있으나, 정확한 분자생물학적 기전은 밝혀져 있지 않은 상태이다. 본 연구에서는 sulforaphane의 항암작용 기전을 조사하기 위하여 HepG2 인체간암세포의 증식에 미치는 sulforaphane의 영 향을 조사하였다. Sulforaphane의 처리에 의한 HepG2 세포의 증식억제 및 형태적 변형은 세포주기 G2/M arrest 및 apoptosis 유발과 밀접한 관련이 있음을 알 수 있었다. RT-PCR 및 Western blot 분석 결과, sulforaphane 처리에 의하여 cyclin A 및 cyclin B1, Cdc2의 발현이 단백질 수준에서 선택적으로 저하되었으며, 종양억제 유전자 p53 및 Cdk inhibitor p21의 발현은 전사 및 번역 수준에서 sulforaphane 처리 농도 의존적으로 증가되었다. Sulforaphane의 항암 기전을 규명하기 위해서는 더 많은 연구가 부가적으로 필요하겠지만, 본 연구의 결과들에 의하면 sulforaphane은 강력한 인체암세포의 증식 억제 및 항암작용이 있을 것을 시사하여 준다고 할 수 있다.

• 동의생리병리학회지
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• 제19권4호
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• pp.1050-1054
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• 2005

Recently, arsenic compounds were considered as novel agents for treatment of acute promyelocytic leukemia and malignant tumors. However, it showed severe toxicity effect on normal tissue at the same time. In this study, to investigate the possible molecular mechanism (s) of arsenic compounds as candidate of anti-cancer drugs, we compared the abilities of two arsenic compounds, tetraarsenic oxide $(AS_4O_6)$ and arsenic trioxide (diarsenic oxide, $As_2O_3$), to induce cell growth inhibition as well as apoptosis induction in A549 human non-small cell lung cancer cells. Both $As_4O_6\;and\;As_2O_3$ treatment declined the cell growth and viability of A549 cells in a concentration-dependent manner, which was associated with induction of G1 arrest of the cell cycle and apoptotic cell death. However, $As_4O_6$ induced growth inhibition and apoptosis in A549 cells at much lower concentrations than $As_2O_3.\;As_4O_6$ down-regulated the levels of anti-apoptotic Bcl-2 protein, however, the levels of Bax, a pro-apoptotic protein, were up-regulated in a dose-dependent manner. In conclusion, $As_4O_6$ might be a new arsenic compound which may induce apoptosis in A549 cells by modulation the Bcl-2 family and deserves further evaluation.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Dietary and Medicinal Antimutgens and Anticarcinogens
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• pp.149-149
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• 2001

Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a phytoalexin found in grapes and wines is a potent antioxidant with cancer-preventive properties, the mechanism by which resveratrol imparts cancer chemopreventive effect is poorly defined. The aim of the present study was to further elucidate the possible mechanisms by which resveratrol exerts its anti-proliferative action in cultured human lung cancer cells.(omitted)

• The Korean Journal of Physiology and Pharmacology
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• 제14권6호
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• pp.391-397
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• 2010

E2F transcription factors and their target genes have been known to play an important role in cell growth control. We found that curcumin, a polyphenolic phytochemical isolated from the plant Curcuma longa, markedly suppressed E2F4 expression in HCT116 colon cancer cells. Hydrogen peroxide was also found to decrease E2F4 protein level, indicating the involvement of reactive oxygen species (ROS) in curucmin-induced downregulation of E2F4 expression. Involvement of ROS in E2F4 downregulation in response to curcumin was confirmed by the result that pretreatment of cells with N-acetylcystein (NAC) before exposure of curcumin almost completely blocked the reduction of E2F4 expression at the protein as well as mRNA level. Anti-proliferative effect of curcumin was also suppressed by NAC which is consistent to previous reports showing curcumin-superoxide production and induction of poly (ADP-ribose) polymerase (PARP) cleavage as well as apoptosis. Expression of several genes, cyclin A, p21, and p27, which has been shown to be regulated in E2F4-dependent manner and involved in the cell cycle progression was also affected by curcumin. Moreover, decreased (cyclin A) and increased (p21 and p27) expression of these E2F4 downstream genes by curcumin was restored by pretreatment of cells with NAC and E2F4 overexpression which is induced by doxycycline. In addition, E2F4 overexpression was observed to partially ameliorate curcumin-induced growth inhibition by cell viability assay. Taken together, we found curcumin-induced ROS down-regulation of E2F4 expression and modulation of E2F4 target genes which finally lead to the apoptotic cell death in HCT116 colon cancer cells, suggesting that E2F4 appears to be a novel determinant of curcumin-induced cytotoxicity.

• Journal of Applied Biological Chemistry
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• 제63권1호
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• pp.103-110
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• 2020

Objective: The objective of our study was to investigate anti-cancer effects of Danggui Liuhuang Decoction extract bioconverted by protease liquid coenzyme of Aspergillus kawachii (DLD-BE), compared to a non-bioconverted DLD extract (DLD-E) and determine the underlying mechanisms. Methods: DLD-E and DLD-BE were evaluated for their ability to modulate these signaling pathways and suppress the proliferation of human colorectal cancer (CRC) cells, HCT-116, LoVo, and HT-29. The anti-cancer effects of DLD-E and DLD-BE were measured by using proliferation and migration assays, cell cycle analysis, Western blots, and real-time PCR. Results: In this study, treatment with DLD-E and DLD-BE at concentrations of 25-100 ㎍/mL inhibited proliferation and migration in human CRC cells. DLD-BE induced apoptotic cell death and decreased COX-2 expression in HT-29 cells. The mechanisms of action included modulation of the AKT and extracellular-signal-regulated kinase signaling cascades along with inhibition of COX-2 expression. The results demonstrate novel anti-cancer mechanisms of DLD-BE against the growth of human CRC cells. Thus, we propose that DLD-BE can be developed as a more potent supplement to inhibit colorectal tumor growth and intestinal inflammation than DLD-E.

• 대한약침학회지
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• 제20권3호
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• pp.158-172
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• 2017

Nigella sativa (N. sativa, family Ranunculaceae) is a medicinal plant that has been widely used for centuries throughout the world as a natural remedy. A wide range of chemical compounds found in N. sativa expresses its vast therapeutic effects. Thymoquinone (TQ) is the main component (up to 50%) in the essential oil of N. sativa. Also, pinene (up to 15%), p-cymene (40%), thymohydroquinone (THQ), thymol (THY), and dithymoquinone (DTQ) are other pharmacologically active compounds of its oil. Other terpenoid compounds, such as carvacrol, carvone, 4-terpineol, limonenes, and citronellol, are also found in small quantities in its oil. The main pharmacological characteristics of this plant are immune system stimulatory, anti-inflammatory, hypotensive, hepatoprotective, antioxidant, anti-cancer, hypoglycemic, anti-tussive, milk production, uricosuric, choleretic, anti-fertility, and spasmolytic properties. In this regard, we have searched the scientific databases PubMed, Web of Science, and Google Scholar with keywords of N. sativa, anti-cancer, apoptotic effect, antitumor, antioxidant, and malignancy over the period from 2000 to 2017. The effectiveness of N. sativa against cancer in the blood system, kidneys, lungs, prostate, liver, and breast and on many malignant cell lines has been shown in many studies, but the molecular mechanisms behind that anti-cancer role are still not clearly understood. From among the many effects of N. sativa, including its anti-proliferative effect, cell cycle arrest, apoptosis induction, ROS generation, anti-metastasis/anti-angiogenesis effects, Akt pathway control, modulation of multiple molecular targets, including p53, p73, STAT-3, PTEN, and $PPAR-{\gamma}$, and activation of caspases, the main suggestive anti-cancer mechanisms of N. sativa are its free radical scavenger activity and the preservation of various anti-oxidant enzyme activities, such as glutathione peroxidase, catalase, and glutathione-S-transferase. In this review, we highlight the molecular mechanisms of apoptosis and the anti-cancer effects of N. sativa, with a focus on its molecular targets in apoptosis pathways.