• The Korean Journal of Physiology and Pharmacology
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• v.1 no.5
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• pp.515-521
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• 1997

Endothelial cells play a central role in the inflammatory processes, and activation of nuclear factor kappa B ($NF-_{\kappa}B$) is a key component in that inflammatory processes. Previously, we reported that tumor necrosis factor alpha($TNF{\alpha}$) had protective effect of cell death induced by serum deprivation and this protection was related to $NF-_{\kappa}B$ activation. Inducible nitric oxide synthase (iNOS) is a member of the molecules which transcription is regulated mainly by $NF-_{\kappa}B$. And the role of nitric oxide (NO) generated by iNOS on cell viability is still controversial. To elucidate the mechanism of $TNF{\alpha}$ and $NF-_{\kappa}B$ activation on cell death protection, we investigate the effect of NO on the cell death induced by serum- deprivation in bovine cerebral endothelial cells in this study. Addition of $TNF{\alpha}$, which are inducer of iNOS, prevented serum-deprivation induced cell death. Increased expression of iNOS was confirmed indirectly by nitrite measurement. When selective iNOS inhibitors were treated, the protective effect of $TNF{\alpha}$ on cell death was partially blocked, suggesting that iNOS expression was involved in controlling cell death. Exogenously added NO substrate (L-arginine) and NO donors (sodium nitroprusside and S-nitroso-N-acetylpenicillamine) also inhibited the cell death induced by serum deprivation. These results suggest that NO has protective effect on bovine cerebral endothelial cell death induced by serum-deprivation and that iNOS is one of the possible target molecules by which $NF-_{\kappa}B$ exerts its cytoprotective effect.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.4
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• pp.331-338
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• 2013

AMP-activated protein kinase (AMPK), an important regulator of energy metabolism, is activated in response to cellular stress when intracellular levels of AMP increase. We investigated the neuroprotective effects of AMPK against scopolamine-induced memory impairment in vivo and glutamate-induced cytotoxicity in vitro. An adenovirus expressing AMPK wild type alpha subunit (WT) or a dominant negative form (DN) was injected into the hippocampus of rats using a stereotaxic apparatus. The AMPK WT-injected rats showed significant reversal of the scopolamine induced cognitive deficit as evaluated by escape latency in the Morris water maze. In addition, they showed enhanced acetylcholinesterase (AChE)-reactive neurons in the hippocampus, implying increased cholinergic activity in response to AMPK. We also studied the cellular mechanism by which AMPK protects against glutamate-induced cell death in primary cultured rat hippocampal neurons. We further demonstrated that AMPK WT-infected cells increased cell viability and reduced Annexin V positive hippocampal neurons. Western blot analysis indicated that AMPK WT-infected cells reduced the expression of Bax and had no effects on Bcl-2, which resulted in a decreased Bax/Bcl-2 ratio. These data suggest that AMPK is a useful cognitive impairment treatment target, and that its beneficial effects are mediated via the protective capacity of hippocampal neurons.

• YAKHAK HOEJI
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• v.49 no.4
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• pp.355-364
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• 2005

A neurotoxin, 6-hydroxydopamine (6-OHDA) has long been used to form a Parkinson's disease (PD) model by inducing the lesion in catecholaminergic pathways, particularly the nigrostriatal dopamine (DA) pathway. Whereas l-deprenyl, a selective inhibitor of monoamine oxidase (MAO) type B, is now widely used in the treatment of PD, the precise action mechanism of the drug remains elusive. In this study, we investigated whether l-deprenyl shows protective effect against the DA depletion induced by 6-OHDA in rat brain, and against 6-OHDA-induced neurotoxicity and oxidative stress in catecholaminergic neuroblastoma SH-SY5Y cells that are known to lack MAO-B activity. Pretreatment of l-deprenyl significantly enhanced the striatal DA, 3,4-dihydroxyphenylacetic acid, homovanilic acid, and 3-methoxytyramine levels compared to the untreated 6-OHDA-lesioned rat, indicating that l-deprenyl pretreatment prevents 6-OHDA-induced depletion of not only striatal dopamine but also its metabolites. Treatment of 6-OHDA for 24hrs decreased the cell viability and increase the generation of ROS in dose-dependent manners. We further investigated whether caspase activity is involved in the action of l-deprenyl. Treatment of l-deprenyl $(0.1\~100{\mu}M)$ did not produce any changes in 6-OHDA-induced cleavage of poly (ADP-ridose) polymerase in SH-SY5Y cells. Our results suggest that the neuroprotective effect of l-deprenyl against 6-OHDA is due to its increased scavenger activity, but independent of inhibition of MAO-B or caspase-3 activation.

• Korean Journal of Veterinary Research
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• v.43 no.4
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• pp.563-571
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• 2003

Dysfunction of mesangial cells has been contributed to the onset of diabetic nephropathy. Insulin like growth factors (IGFs) are also implicated in the pathogenesis of diabetic nephropathy. However, it is not yet known about the effect of high glucose on IGF-I and IGF-II secretion in the mesangial cells. Furthermore, the relationship between cAMP and high glucose on the secretion of IGFs was not elucidated. Thus, we examined the mechanisms by which high glucose regulates secretion of IGFs in mesangial cells. Glucose increased IGF-I secretion in a time- (>8 hr) and dose- (>15 mM) dependent manner (p<0.05). Stimulatory effect of high glucose on IGF-I secretion is predominantly observed in 25 mM glucose (high glucose), while 25 mM glucose did not affect cell viability and lactate dehydrogenase release. High glucose also increased IGF-II secretion. The increase of IGF-I and IGF-II secretion is not mediated by osmotic effect, since mannitol and L-glucose did not affect IGF-I and IGF-II secretion. 8-Br-cAMP mimicked high glucose-induced secretion of IGF-I and IGF-II. High glucose-induced stimulation of IGF-I and IGF-II secretion was blocked not by pertussis toxin but by SQ 22536 (adenylate cyclase inhibitor). Rp-cAMP (cAMP antagonist), and myristoylated protein kinase A (PKA) inhibitor amide 14-22 (protein kinase A inhibitor). These results suggest that cAMP/PKA pathways independent of Gi protein may mediate high glucose-induced increase of IGF-I and IGF-II secretion in mesangial cells. Indeed, glucose (>15 mM glucose) increased cAMP formation. In conclusion, high glucose stimulates IGF-I and IGF-II secretion via cAMP/PKA pathway in mesangial cells.

• Korean Journal of Plant Resources
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• v.33 no.5
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• pp.460-466
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• 2020

In this study, we evaluated the anti-cancer activity and potential molecular mechanism of 70% ethanol extracts of leaves from Rodgersia podophylla against human colorectal cancer cells, HCT116. RPL dose-dependently decreased the cell viability through RPL-induced apoptosis in HCT116 cells. RPL induced inactivation the nuclear factor κB(NF-κB) through blocking IκB-α degradtion and P65 nuclear accumulation. The inhibition of GSK3β by LiCl attenuated RP-L-mediated NF-κB signaling inactivation. In addition, RP-L induced GSK3β activation. Based on these findings, RPL may be a potential candidate for the development of chemopreventive or therapeutic agents for human colorectal cancer.

• Journal of Acupuncture Research
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• v.22 no.6
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• pp.37-50
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• 2005

Objectives : The purpose of this study was to investigate the anti-caner effect of Bee Venom and Melittin on the prostatic cancer cell(PC-3). The goal of study is to ascertain whether Bee Venom and Melittin inhibits the cell growth and cell cycle of PC-3, or the expression of relative genes and whether the regression of PC-3 cell growth is due to cell death or the expression of gene related to apoptosis. Methods : After the treatment of Pc-3 cells with Bee Venom and Melittin, we performed Fluorescence microscope, MTT assay, Western blotting, Flow cytometry, PAGE electrophoresis and Surface plasmon resonance analysis to identify the cell viability, apoptosis and gene related to apoptosis. Results : 1. Compared with Control cell, the inhibition of cell growth reduced in proportion with the dose of Bee Venom or Melittin($0{\sim}10{\mu}g/ml$) in PC-3. 2. In PC-3, Cell viabilities of Bee Venom or Melittin treatment was decreased significantly. 3. The nucli of Control cells were stained round and homogenous in DAPI staining, but those of PC-3 were stained condense and splitted. 4. In PC-3, apoptosis of Bee Venom or Melittin treatment was increased significantly. 5. Bax, Caspase-3 and P ARP of Bee Venom or Melittin treatment was increased significantly and Bcl-2 of Bee Venom or Melittin treatment was decreased significantly. Caspase-9 of Bee venom treatment was increased significantly. Conclusion : These results indicate that Bee Venom and Melittin inhibits the growth of prostate cancer cells, has anti-cancer effects by inducing apoptosis. We wish that the anti-cancer effects of Bee Venom and Melittin are used to clinical caner treatment.

• International Journal of Oral Biology
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• v.39 no.1
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• pp.23-33
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• 2014

Several studies have shown that curcumin, which is derived from the rhizomes of turmeric, possesses antimicrobial, antioxidant and anti-inflammatory properties. The antitumor properties of curcumin have also now been demonstrated more recently in different cancers. This study was undertaken to investigate the modulation of cell cycle-related proteins and the mechanisms underlying apoptosis induction by curcumin in the SCC25 human tongue squamous cell carcinoma cell line. Curcumin treatment of the SCC25 cells resulted in a time- and dose-dependent reduction in cell viability and cell growth, and onset of apoptotic cell death. The curcumin-treated SCC25 cells showed several types of apoptotic manifestations, such as nuclear condensation, DNA fragmentation, reduced MMP and proteasome activity, and a decreased DNA content. In addition, the treated SCC25 cells showed a release of cytochrome c into the cytosol, translocation of AIF and DFF40/CAD into the nuclei, a significant shift in the Bax/Bcl-2 ratio, and the activation of caspase-9, caspase-7, caspase-6, caspase-3, PARP, lamin A/C, and DFF45/ICAD. Furthermore, curcumin exposure resulted in a downregulation of G1 cell cycle-related proteins and upregulation of $p27^{KIP1}$. Taken together, our findings demonstrate that curcumin strongly inhibits cell proliferation by modulating the expression of G1 cell cycle-related proteins and inducing apoptosis via proteasomal, mitochondrial, and caspase cascades in SCC25 cells.

• International Journal of Oral Biology
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• v.41 no.4
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• pp.163-173
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• 2016

Flavonoid myricetin, usually found in tea and medicinal plants, has antioxidant and anti-inflammatory effects. Our objectives in this study were to verify the effects of myricetin on periodontal ligament fibroblasts (PDLFs) under inflammatory conditions and to observe its effects on osteoclast generation and on cytokine expression in RAW264.7 cells. To determine the effects of myricetin on PDLFs, we examined the expression and activity of proteolytic enzymes, including MMP-1, MMP-2, and MMP-8, which all play an important role in chronic periodontitis. We observed the effects of myricetin on intracellular signal transduction to verify the molecular mechanism involved. By measuring the formation of TRAP-positive multinucleated cells and the expression and activity of MMP-8, we were able to assess the effects of myricetin on osteoclast generation. In addition, by measuring the secretion of IL-6 and NO, we could evaluate the effects of myricetin on inflammatory mediators. We found that Myricetin had no effect on the viability of the PDLFs in the presence of inflammation, but it did decrease both the expression of MMP-1 and MMP-8 and the enzyme activity of MMP-2 and MMP-8 in these fibroblasts. Myricetin also decreased the lipopolysaccharide-stimulated phosphorylation of JNK, p38 signaling, IKKB, AKT, and p65RelA in the PDLFs. In the RAW264.7 cells, myricetin inhibited both the expression and the activity of MMP-8. Furthermore, Myricetin not only suppressed the generation of LPS-stimulated osteoclasts, but it also slightly inhibited LPS-stimulated degradation of IkB and decreased the release of LPS-induced IL-6 and NO. These findings suggest that myricetin alleviates the tissue-destructive processes that occur during periodontal inflammation.

• International Journal of Oral Biology
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• v.41 no.4
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• pp.183-190
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• 2016

Anthricin (Deoxypodophyllotoxin), a naturally occurring flavolignan, has well known anti-cancer properties in several cancer cells, such as prostate cancer, cervical carcinoma and pancreatic cancer. However, the effects of Anthricin are currently unknown in oral cancer. We examined the anticancer effect and mechanism of action of Anthricin in human FaDu hypopharyngeal squamous carcinoma cells. Our data showed that Anthricin inhibits cell viability in a dose- and time-dependent manner ($IC_{50}$ 50 nM) in the MTT assay and Live & Dead assay. In addition, Anthricin treated FaDu cells showed marked apoptosis by DAPI stain and FACS. Furthermore, Anthricin activates anti-apoptotic factors such as caspase-3, -9 and poly (ADP-ribose) polymerase (PARP), suggesting that caspase-mediated pathways are involved in Anthricin- induced apoptosis. Anthricin treatment also leads to accumulation of the pro-apoptotic factor Bax, followed by inhibition of cell growth. Taken together, these results indicate that Anthricn-induced cell death of human FaDu hypopharyngeal squamous carcinoma cells is mediated by mitochondrial-dependent apoptotic pathway. In summary, our findings provide a framework for further exploration on Anthricin as a novel chemotherapeutic drug for human oral cancer.

• BMB Reports
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• v.39 no.5
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• pp.492-501
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• 2006

Since differentiation therapy is one of the promising strategies for treatment of leukemia, universal efforts have been focused on finding new differentiating agents. In that respect, we used guanosine 5'-triphosphate (GTP) to study its effects on K562 cell line. GTP, at concentrations between 25-200 ${\mu}M$, inhibited proliferation (3-90%) and induced 5-78% increase in benzidine-positive cells after 6-days of treatments of K562 cells. Flow cytometric analyses of glycophorine A (GPA) showed that GTP can induce expression of this marker in more mature erythroid cells in a time- and dose-dependent manner. These effects of GTP were also accompanied with inhibition of DNA synthesis (measured by [$^3H$]-thymidine incorporation) and early S-phase cell cycle arrest by 96 h of exposure. In contrast, no detectable effects were observed when GTP administered to unstimulated human peripheral blood lymphocytes (PBL). However, GTP induced an increase in proliferation, DNA synthesis and viability of mitogen-stimulated PBL cells. In addition, growth inhibition and differentiating effects of GTP were also induced by its corresponding nucleotides GDP, GMP and guanosine (Guo). In heat-inactivated medium, where rapid degradation of GTP via extracellular nucleotidases is slow, the anti-proliferative and differentiating effects of all type of guanine nucleotides (except Guo) were significantly decreased. Moreover, adenosine, as an inhibitor of Guo transporter system, markedly reduced the GTP effects in K562 cells, suggesting that the extracellulr degradation of GTP or its final conversion to Guo may account for the mechanism of GTP effects. This view is further supported by the fact that GTP and Guo are both capable of impeding the effects of mycophenolic acid. In conclusion, our data will hopefully have important impact on pharmaceutical evaluation of guanine nucleotides for leukemia treatments.