• The Journal of Korean Society for Radiation Therapy
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• v.12 no.1
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• pp.166-173
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• 2000

Angiopoietin-1(Ang-1) is a vasculogenic factor that signals through the endothelial cell-specific Tie2 receptor tyrosine kinase. We examined the effect of angiopoietin-1(Ang-1) on radiation-induced apoptosis in human umbilical vein endothelial cells(HUVECS) and receptor/second messenger signal transduction pathway for Ang-1's effect on HUVECs. The percent of apoptotic cells under control condition(0Gy) was $8.2\%$. Irradiation induced apoptosis was increased in a dose(1, 5, 10, and 15Gy)- and time 12, 24, 48 and 72hr)-dependent manner. The percent of apoptotic cells was approximately $34.9\%$ after 15 Gy of irradiation. Under these conditions, pretreatment with Ang-1's (50, 100, 200, and 400 ng/ml) inhibited irradiation-induced apoptosis in human umbilical vein endothelial cells in a dose-dependent manner. Two hundred ng/ml of Ang-1 inhibited approximately $55-60\%$ of the apoptotic events that occurred in the 10 Gy-irradiated cells. Pre-treatment with soluble Tie2 receptor, but not Tie1 receptor, blocked the Ang-1's antiapoptotic effects. Phosphatidylinositol 3'-kinase (P13-kinase) specific inhibitor, wortmanin and LY294002, blocked the Ang-1-induced antiapoptotic effect. Ang-1 promotes the survival of endothelial cells in irradiation-induced apoptosis through Tie2 receptor binding and P13-kinase activation. Pretreatment of Ang-1 could be beneficial in maintaining normal endothelial cell integrity during irradiation therapy.

• Biomedical Science Letters
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• v.18 no.3
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• pp.307-309
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• 2012

(S)-(+)-3(3,4-dihydroxy-phenyl)-acrylic acid 2,2-dimethyl-8-oxo3,4-dihydro-2H,8H-pyrano[3,2-g]Chromen-3-yl-ester (Compound 6, C6) is synthesized from (S)-(+)-decursin and attenuates the pathophysiologic progression of asthma in a ovalbumin-induced asthmatic mouse model. In the present study, we examined the effect of C6 on spontaneous apoptosis of eosinophils and neutrophils of normal and asthmatic subjects. C6 increased the apoptosis of asthmatic eosinophils in a dose-dependent manner, but it inhibited neutrophil apoptosis. C6 has no effect on apoptosis of normal eosinophils and neutrophils. LY294002, an inhibitor of PI3K, rottlerin, an inhibitor of $PKC{\delta}$, Ro-31-8425, an inhibitor of classical PKC inhibitor, PD98059, an inhibitor of MEK, and BAY 11-7085, an inhibitor of NF-${\kappa}B$, blocked the inhibitory effect on apoptosis of asthmatic neutrophils due to C6. These results indicate that C6 may be valuable as a therapeutic agent for the treatment of asthma.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.1
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• pp.121-126
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• 2020

The ezrin-radixin-moesin (ERM) proteins are a family of membrane-associated proteins known to play roles in cell-shape determination as well as in signaling pathways. We have previously shown that amphetamine decreases phosphorylation levels of these proteins in the nucleus accumbens (NAcc), an important neuronal substrate mediating rewarding effects of drugs of abuse. In the present study, we further examined what molecular pathways may be involved in this process. By direct microinjection of LY294002, a PI3 kinase inhibitor, or of S9 peptide, a proposed GSK3β activator, into the NAcc core, we found that phosphorylation levels of ERM as well as of GSK3β in this site are simultaneously decreased. These results indicate that ERM proteins are under the regulation of Akt-GSK3β signaling pathway in the NAcc core. The present findings have a significant implication to a novel signal pathway possibly leading to structural plasticity in relation with drug addiction.

• BMB Reports
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• v.50 no.12
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• pp.615-620
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• 2017

Fibronectin (FN) plays important roles in the EMT in a variety of cancer cell types. However, the mechanism by which FN expression is regulated in tamoxifen-resistant (TamR) breast cancer cells has not yet been fully elucidated. Aberrant FN expression was associated with poor prognosis in patients with luminal type A breast cancer. In addition, FN was upregulated in TamR cells. To investigate the mechanism by which FN expression is regulated, we assessed the levels of phosphorylated Akt, JNK, and STAT3 and found that they were all increased in TamR cells. Induction of FN expression was dampened by LY294002 or AKT IV in TamR cells. Furthermore, FN expression was increased by constitutively active (CA)-Akt overexpression in tamoxifen-sensitive MCF7 (TamS) cells and colony formation of TamR cells was blocked by AKT IV treatment. Taken together, these results demonstrate that FN expression is upregulated through the PI-3K/Akt pathway in tamoxifen-resistant breast cancer cells.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1079-1085
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• 2008

The chemopreventive activity of sulforaphane (SFN) occurs through its inhibition of carcinogen-activating enzymes and its induction of detoxification enzymes. However, the exact mechanisms by which SFN exerts its anti-carcinogenic effects are not fully understood. Therefore, the mechanisms underlying the cytoprotective effects of SFN were examined in MCF-7 breast cancer cells. Exposure of cells to SFN (10 ${\mu}M$) induced a transcriptional change in the AKR1C3 gene, which is one of aldo-keto reductases (AKRs) family that is associated with detoxification and antioxidant response. Further analysis revealed that SFN elicited a dose- and time-dependent increase in the expression of both the NRF2 and AKR1C3 proteins. Moreover, this up-regulation of AKR1C3 was inhibited by pretreatment with antioxidant, N-acetyl-L-cysteine (NAC), which suggests that the up-regulation of AKR1C3 expression induced by SFN involves reactive oxygen species (ROS) signaling. Furthermore, pretreatment of cells with LY294002, a pharmacologic inhibitor of phosphatidylinositol 3-kinase (PI3K), suppressed the SFN-augmented Nrf2 activation and AKR1C3 expression; however, inhibition of PKC or MEK1/2 signaling with $G\ddot{o}6976$ or PD98059, respectively, did not alter SFN-induced AKR1C3 expression. Collectively, these data suggest that SFN can modulate the expression of the AKR1C3 in MCF-7 cells by activation of PI3K via the generation of ROS.

• Biomolecules & Therapeutics
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• v.19 no.3
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• pp.302-307
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• 2011

Peptidoglycan (PGN) is detected in inflammatory cell-rich regions of human atheromatous plaques. The present study investigated the effects of PGN on CC chemokine ligand 3 (CCL3) expression, which is elevated in the atherosclerotic arteries, and determined cellular factors involved in PGN-mediated CCL3 up-regulation in mononuclear cells, with the goal of understanding the molecular mechanisms of inflammatory responses to bacterial pathogen-associated molecular patterns in diseased arteries. Exposure of human monocytic leukemia THP-1 cells to PGN resulted in enhanced secretion of CCL3 and profound induction of the CCL3 gene transcript. Both events were abrogated by oxidized 1-palmitoyl-2-arachidonosyl-sn-phosphatidylcholine, an inhibitor of Toll-like receptors 2/4. Pharmacological inhibitors such as U0126, SP6001250, Akt inhibitor IV, rapamycin, RO318220, diphenyleneiodonium chloride, and N-acetylcysteine also significantly attenuated PGN-mediated CCL3 up-regulation. However, polymyxin B, LY294002, and SB202190 did not influence CCL3 expression. We propose that PGN contributes to enhanced CCL3 expression in atherosclerotic plaques and that Toll-like receptors (TLR2), Akt, mTOR, mitogen-activated protein kinase, and reactive oxygen species are involved in that process.

• Biomedical Science Letters
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• v.20 no.4
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• pp.244-249
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• 2014

Arazyme is a metalloprotease secreted by Aranicola proteolyticus that was previously shown to suppress cytokine expression of keratinocytes and endothelial cells and inhibit histopathological features in an atopic dermatitis-like animal model. However, the regulatory effects of arazyme in other allergic diseases have yet to be elucidated. In this study, we investigated whether arazyme is effective against neutrophil apoptosis in allergic diseases such as allergic rhinitis and asthma. Arazyme inhibited neutrophil apoptosis of normal subjects in a dose-dependent manner. However, the antiapoptotic effect of arazyme was reversed by LY294002, an inhibitor of PI3K, AKTi, an inhibitor of Akt, PD98059, an inhibitor of MEK, and BAY-11-7085, an inhibitor of NF-${\kappa}B$. Arazyme induced activation of NF-${\kappa}B$ via PI3K/Akt/ERK pathway. The anti-apoptotic effect of arazyme is associated with inhibition of cleavage of caspase 3 and caspase 9. Arazyme inhibited constitutive apoptosis of neutrophil in a dose-dependent manner in allergic subjects, and its mechanism was shown to be associated with PI3K/Akt/ERK/NF-${\kappa}B$. The results presented here improve our understanding of neutrophil apoptosis regulation and will facilitate development of drugs for treatment of allergic diseases.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2001.11a
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• pp.103-103
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• 2001

인간유방상피세포에서 H-ras가 침윤성과 세포 이동성을 유도한다는 것을 이 전연구에서 밝혔다. Phosphatidylinositol 3-kinase(PI3K)는 세포 이동성에서 중요한 역할을 하는 것으로 보고되고 있다. 본 연구에서 인간유방상피세포인 MCF10A에서 H-ras에 의해 유도된 침윤성에 PI3K가 어떠한 영향을 미치는지 살펴보고자 하였다. PI3K의 활성은 PI3K의 downstream molecule인 Akt의 인산화를 Western blot으로 확인하였다. Akt는 MCF10A, H-ras, N-ras MCF10A 세포에서 같은 정도로 발현되는 반면, 인산화된 Akt는 MCF10A 세포에 비해 H-ras MCF10A 세포와 N-ras MCF10A 세포에서 현저히 높게 나타났다. 이상의 결과로서 H-ras, N-ras 둘 다 PI3K를 활성화시키며, 침윤성과 세포이동성이 없는 N-ras MCF10A 세포에서도 PI3K가 활성화되었으므로, PI3K의 활성은 세포침윤성과 이동성을 유도하는데에 있어서 충분하지는 않음을 말해준다. PI3K의 저해제인 LY294002와 wortmannin을 세포에 처리하였을 때 세포침윤성과 이동성이 유의성 있게 감소되었다. 이상의 결과는 MCF10A 세포의 침윤성과 이동설에 있어서 PI3K의 활성이 충분하지는 않지만 반드시 필요하다는 것을 알 수 있었다.

• Biomolecules & Therapeutics
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• v.24 no.6
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• pp.589-594
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• 2016

Insulin is a peptide hormone of the endocrine pancreas and exerts a wide variety of physiological actions in insulin sensitive tissues, such as regulation of glucose homeostasis, cell growth, differentiation, learning and memory. However, the role of insulin in osteoblast cells remains to be fully characterized. In this study, we demonstrated that the insulin (100 nM) has the ability to stimulate the phosphorylation of protein kinase B (Akt/PKB) and extracellular signal-regulated kinase (ERK) and the levels of inhibin-${\beta}E$ in the osteoblast-like UMR-106 cells. This insulin-stimulated activities were abolished by the PI3K and MEK1 inhibitors LY294002 and PD98059, respectively. This is the first report proving that insulin is a potential candidate that enables the actions of inhibin-${\beta}E$ subunit of the TGF-${\beta}$ family. The current investigation provides a foundation for the realization of insulin as a potential stimulator in survival signaling pathways in osteoblast-like UMR-106 cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.31 no.3
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• pp.167-172
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• 2017

In this study, we investigated the effect of Puerariae Radix ethanol extracts (EPR). The effect of the EPR on proliferation of human hair dermal papilla cells(HHDPCs) by MTT assay and observed Expression of mechanisms that regulate cell proliferation extracellular signal-regulated kinase(ERK) and Akt by western blot. The results showed EPR increased the proliferation of HHDPCs and up-regulation phosphorylation of ERK and Akt. ERK and Akt increased by EPR inhibited phosphorylation by PD98059 (ERK inhibitor) and LY294002 (Akt inhibitor), and cell proliferation was also inhibited. These results suggested EPR increases the proliferation of HHDPCs through phosphorylation of ERK and Akt, and therefore is a beneficial effect for the alopecia treatment.