• Archives of Pharmacal Research
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• v.27 no.1
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• pp.68-76
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• 2004

Mistletoe lectin has been reported to induce apoptosis in different cancer cell lines in vitro and to show antitumor activity against a variety of tumors in animal models. We previously demonstrated the Korean mistletoe lectin (Viscum album var. coloratum, VCA)-induced apoptosis by down-regulation of Bcl-2 and telomerase activity and by up-regulation of Bax through p53- and p21-independent pathway in hepatoma cells. In the present study, we observed the induction of apoptotic cell death through activation of caspase-3 and the inhibition of telomerase activity through transcriptional down-regulation of hTERT in the VCA-treated A253 cells. We also observed the inhibition of telomerase activity and induction of apoptosis resulted from dephosphorylation of Akt in the survival signaling pathways. In addition, combining VCA with the inhibitors of phosphatidylinositol 3-kinase (PI3-kinase) upstream of Akt, wortmannin and LY294002 showed an additive inhibitory effect of telomerase activity. In contrast, the inhibitor of protein phosphatase 2A (PP2A), okadaic acid inhibited VCA-induced dephosphorylation of Akt and inhibition of telomerase activity. Taken together, VCA induces apoptotic cell death through Akt signaling pathway in correlated with the inhibition of telomerase activity and the activation of caspase-3. From these results, together with our previous studies, we suggest that VCA triggers molecular changes that resulting in the inhibition of cell growth and the induction of apoptotic cell death of cancer cells, which suggest that VCA may be useful as chemotherapeutic agent for cancer cells.

• Journal of Photoscience
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• v.9 no.2
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• pp.485-487
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• 2002

Cells receive signals for survival as well as death, and the balance between the two ultimately determines the fate of the cells. UV-triggered apoptotic signaling has been well documented, whereas UV-induced survival effects have received little attention. We have reported previously that UVB irradiation prevented apoptosis, which was partly dependent on activation of the phosphatidylinositol 3-kinase (PI3-kinase)/ Akt pathway. In this study, anti-apoptotic effects of UV with different wavelength ranges, UVA, UVB and UVC, were examined. NIH3T3 cells showed apoptotic cell death by detachment from the extracellular matrix under serum-free conditions, which was prevented by all wavelengths. However, the effect of UVA was less than those of UVB and UVC. Reduction of mitochondrial transmembrane potential and activation of caspase-9 and -3 were suppressed by all three wavelengths of UV, showing wavelength-dependent effects as mentioned above. The PI3-kinase inhibitor wortmannin partially inhibittrl the UVB and UVC-induced suppression of apoptosis, but not the inhibitoty effect of UVA. The Akt phosphotylation by UVB and UVC was completely inhibittrl by addition of wortmannin, but that by UVA was not P38 MAP kinase inhibitor SB203580 partially inhibited the UVB and UVC-induced suppression of apoptosis and Akt phosphotylation, and completely inhibited UVA-induced those. These results suggested the existence of two different survival pathways leading to suppression of apoptosis, one for UVA that is independent of the PI3-kinase/Akt pathway and dependent on p38 MAP kinase, and the other for UVB and UVC that is dependent on both pathways.

• The Korean journal of internal medicine
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• v.34 no.1
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• pp.146-155
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• 2019

Background/Aims: Indoxyl sulfate (IS) is a uremic toxin and an important causative factor in the progression of chronic kidney disease. Recently, paricalcitol (19-nor-1,25-dihydroxyvitamin D2) was shown to exhibit protective effects in kidney injury. Here, we investigated the effects of paricalcitol treatment on IS-induced renal tubular injury. Methods: The fluorescent dye 2',7'-dichlorofluorescein diacetate was used to measure intracellular reactive oxygen species (ROS) following IS administration in human renal proximal tubular epithelial (HK-2) cells. The effects of IS on cell viability were determined using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays and levels of apoptosis-related proteins (Bcl-2-associated protein X [Bax] and B-cell lymphoma 2 [Bcl-2]), nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) p65, and phosphorylation of mitogen-activated protein kinase (MAPK) and protein kinase B (Akt) were determined by semiquantitative immunoblotting. The promoter activity of $NF-{\kappa}B$ was measured by luciferase assays and apoptosis was determined by f low cytometry of cells stained with f luorescein isothiocyanate-conjugated Annexin V protein. Results: IS treatment increased ROS production, decreased cell viability and induced apoptosis in HK-2 cells. IS treatment increased the expression of apoptosis-related protein Bax, decreased Bcl-2 expression, and activated phosphorylation of MAPK, $NF-{\kappa}B$ p65, and Akt. In contrast, paricalcitol treatment decreased Bax expression, increased Bcl-2 expression, and inhibited phosphorylation of MAPK, $NF-{\kappa}B$ p65, and Akt in HK-2 cells. $NF-{\kappa}B$ promoter activity was increased following IS, administration and was counteracted by pretreatment with paricalcitol. Additionally, flow cytometry analysis revealed that IS-induced apoptosis was attenuated by paricalcitol treatment, which resulted in decreased numbers of fluorescein isothiocyanate-conjugated Annexin V positive cells. Conclusions: Treatment with paricalcitol inhibited IS-induced apoptosis by regulating MAPK, $NF-{\kappa}B$, and Akt signaling pathway in HK-2 cells.

• Biomedical Science Letters
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• v.15 no.1
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• pp.61-66
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• 2009

Leflunomide is an immunomodulatory agent used for the treatment of rheumatoid arthritis (RA). Leflunomide known as a regulator of iNOS synthesis which largely decreases NO production in diverse cell type. However, the effect of leflunomide on chondrocyte is still poorly understood. In our previous studies, we have shown that direct production of Nitric oxide (NO) by treating chondrocytes with NO donor, sodium nitroprusside (SNP), causes apoptosis via p38 mitogen-activated protein kinase in association with elevation of p53 protein level, caspase-3 activation. In this study, we characterized the molecular mechanism by which A77 1726 inhibit apoptosis. We found that A77 1726 inhibit NO-induced apoptosis as determined by MTT (Thiazolyl Blue Tetrazolium Bromide) assay and DNA fragmentation. The inhibition of apoptosis by A77 1726 was accompanied by increased PI-3 kinase and AKT activities. So, inhibition of phosphatidylinositol (PI)-3kinase with LY294002 rescued apoptosis. Triciribine, the specific inhibitor of AKT, also abolished anti-apoptotic effect. Our results indicate that A77 1726, the active metabolite of leflunomide, mediates NO-induced apoptosis in chondrocytes by modulating up-regulation of PI-3 kinase and AKT.

• Journal of Marine Bioscience and Biotechnology
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• v.15 no.2
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• pp.49-58
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• 2023

Early-stage lung cancer is the deadliest form of the disease. In this study, we investigated the anticancer activity of 5-bromoprotocatechualdehyde (BPCA) extracted from the seaweed Polysiphonia morrowii Harvey (P. morrowii) in lung cancer H460 cells. We extracted P. morrowii powder thrice with 80% aqueous methanol and separated the extract using high-performance liquid chromatography. We then tested BPCA's effects on cell viability, apoptosis, reactive oxygen species (ROS) generation, and protein expression Our results showed that BPCA inhibited tumor cell growth and ROS production and induced apoptosis through mitogen-activated protein kinase (MAPK) and AKT signaling pathways in lung cancer cells. When BPCA was combined with hydrogen peroxide, ROS production and apoptosis increased even further due to the regulation of AKT signaling and JNK-MAPKs pathways. These findings suggest that BPCA induces lung-cancer-cell death through ROS-mediated phosphorylation in AKT/MAPK signaling. This could lead to the development of new and effective treatments for early-stage lung cancer.

• Journal of Life Science
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• v.18 no.12
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• pp.1739-1744
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• 2008

The purpose of this study was investigate the effects of short-term exercise and capsaicin supplementation on serum lipids, antioxidants and Akt contents in diabetic rats whose symptom was induced through the use of 50 mg/kg streptozotocin, 31 white rats were experimented. Rats in one exercise group and another exercise-capsaicin supplementation group exercised on a treadmill maintained by a 15-min run at $0^{\circ}$ inclination five times for a week during two weeks one week after the diabetes was induced. 10 mg of capsaicin per kilogram of weight was orally administered to rats in the capsaicin supplementation group after the diabetes was induced. The serum lipids were analyzed through the use of blood obtained from the incision of the abdomen, and antioxidants and Akt contents were analyzed through the use of livers to reach following conclusions. As for the serum lipids, TG significantly decreased in group DCE and HDL-C was higher than in other groups. ROS significantly decreased in all groups except for group D. CAT significantly increased in group DC, SOD was significantly high in groups DE and GSH was significantly high in all groups except for D. Akt contents significantly increased in group DC and p-Akt in group DE. As a result of this study, it has been found that short-term exercise and the capsaicin supplementation had a significantly effect on the serum lipids, antioxidants and Akt contents.

• Journal of Life Science
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• v.17 no.1 s.81
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• pp.56-63
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• 2007

Insulin stimulates the fusion of intracellular vesicles containing glucose transporter 4 (GLUT4) with plasma membrane in adipocytes and muscle cells. Here we show that adipocyte differentiation results in enhanced insulin sensitivity of glucose uptake. On the other hand, glucose uptake in response to platelet-derived growth factor (PDGF) stimulation was markedly reduced by adipocyte differentiation. Expression level of insulin receptor and caveolin-1 was dramatically increased during adipocyte differentiation. Adipocyte differentiation caused :ilightly enhanced activation of acutely transforming retrovirus AKT8 in rodent T cell lymphoma (Akt) by insulin stimulation. However, activation of Akt by PDGF stimulation was largely reduced. Activation of ERK was not detected in both fibroblasts and adipocytes after stimulation with insulin. PDGF-dependent activation of ERK was reduced by adipocyte differentiation. Insulin-dependent glucose uptake was abrogated by LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor, in both fibroblasts and adipocytes. Also disassembly of caveolae structure by $methyl-\beta-cyclodextrin$ caused impairment of Akt activation and glucose uptake. Finally, insulin receptor, Akt, SH2-domain-containing inositol 5-phosphatase 2 (SHIP2), and regulatory subunit of PI3K are localized at lipid raft domain and the translocation was facilitated upon insulin stimulation. Given these results, we suggest that lipid raft provide proper site for insulin action for glucose uptake.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.3
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• pp.263-268
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• 2015

5-Lipoxygenase (5-LO) plays a pivotal role in the progression of atherosclerosis. Therefore, this study investigated the molecular mechanisms involved in 5-LO expression on monocytes induced by LPS. Stimulation of THP-1 monocytes with LPS ($0{\sim}3{\mu}g/ml$) increased 5-LO promoter activity and 5-LO protein expression in a concentration-dependent manner. LPS-induced 5-LO expression was blocked by pharmacological inhibition of the Akt pathway, but not by inhibitors of MAPK pathways including the ERK, JNK, and p38 MAPK pathways. In line with these results, LPS increased the phosphorylation of Akt, suggesting a role for the Akt pathway in LPS-induced 5-LO expression. In a promoter activity assay conducted to identify transcription factors, both Sp1 and NF-${\kappa}B$ were found to play central roles in 5-LO expression in LPS-treated monocytes. The LPS-enhanced activities of Sp1 and NF-${\kappa}B$ were attenuated by an Akt inhibitor. Moreover, the LPS-enhanced phosphorylation of Akt was significantly attenuated in cells pretreated with an anti-TLR4 antibody. Taken together, 5-LO expression in LPS-stimulated monocytes is regulated at the transcriptional level via TLR4/Akt-mediated activations of Sp1 and NF-${\kappa}B$ pathways in monocytes.

• Journal of Ginseng Research
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• v.46 no.4
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• pp.550-560
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• 2022

Background: The effect of ginsenoside Rh2 (G-Rh2) on mast cell-mediated anaphylaxis remains unclear. Herein, we investigated the effects of G-Rh2 on OVA-induced asthmatic mice and on mast cell-mediated anaphylaxis. Methods: Asthma model was established for evaluating airway changes and ear allergy. RPMCs and RBL-2H3 were used for in vitro experiments. Calcium uptake, histamine release and degranulation were detected. ELISA and Western blot measured cytokine and protein levels, respectively. Results: G-Rh2 inhibited OVA-induced airway remodeling, the production of TNF-α, IL-4, IL-8, IL-1β and the degranulation of mast cells of asthmatic mice. G-Rh2 inhibited the activation of Syk and Lyn in lung tissue of OVA-induced asthmatic mice. G-Rh2 inhibited serum IgE production in OVA induced asthmatic mice. Furthermore, G-Rh2 reduced the ear allergy in IgE-sensitized mice. G-Rh2 decreased the ear thickness. In vitro experiments G-Rh2 significantly reduced calcium uptake and inhibited histamine release and degranulation in RPMCs. In addition, G-Rh2 reduced the production of IL-1β, TNF-α, IL-8, and IL-4 in IgE-sensitized RBL-2H3 cells. Interestingly, G-Rh2 was involved in the FcεRI pathway activation of mast cells and the transduction of the Lyn/Syk signaling pathway. G-Rh2 inhibited PI3K activity in a dose-dependent manner. By blocking the antigen-induced phosphorylation of Lyn, Syk, LAT, PLCγ2, PI3K ERK1/2 and Raf-1 expression, G-Rh2 inhibited the NF-κB, AKT-Nrf2, and p38MAPK-Nrf2 pathways. However, G-Rh2 up-regulated Keap-1 expression. Meanwhile, G-Rh2 reduced the levels of p-AKT, p38MAPK and Nrf2 in RBL-2H3 sensitized IgE cells and inhibited NF-κB signaling pathway activation by activating the AKT-Nrf2 and p38MAPK-Nrf2 pathways. Conclusion: G-Rh2 inhibits mast cell-induced allergic inflammation, which might be mediated by the AKT-Nrf2/NF-kB and p38MAPK-Nrf2/NF-κB signaling pathways.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.23
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• pp.10483-10487
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• 2015

Heptaphylline derivatives are carbazoles in Clausena harmandiana, a medicinal plant that is utilized for headache, stomach ache, and other treatments of illness. The present study examined the effects of heptaphylline and 7-methoxyheptaphylline on apoptosis of human colon adenocarcinoma cells (HT-29 cell line). Quantification of cell viability was performed using cell proliferation assay (MTT assay) and of protein expression through immunoblotting. The results showed that only heptaphylline, but not 7-methoxyheptaphylline, significantly significantly activated cleaved of caspase-3 and poly (ADP-ribose) polymerase (PARP-1) which resulted in HT-29 cell death. We found that heptaphylline activated BH3 interacting-domain death agonist (Bid) and Bak, proapoptotic proteins. In contrast, it suppressed X-linked inhibitor-of-apoptosis protein (XIAP), Bcl-xL and survivin, inhibitors of apoptosis. In addition, heptaphylline inhibited activation of NF-${\kappa}B$/p65 (rel), a regulator of apoptotic regulating proteins by suppressing the activation of Akt and $IKK{\alpha}$, upstream regulators of p65. The findings suggested that heptaphylline induces apoptosis in human colon adenocarcinoma cells.