• 생명과학회지
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• 제21권1호
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• pp.89-95
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• 2011

식품에서 추출한 파이토케미컬은 여러 암종에서 암세포의 증식억제와 apoptosis를 유도한다. 최근에 이러한 파이토케미컬의 세포 내 신호전달 기작에 관한 관심이 높아지고 있으며, 본 연구에서는 파이토케미컬의 일종인 커큐민과 EGCG를 HCT116 대장암세포에 처리함으로써 암세포의 증식억제와 apoptosis 유도 효과를 알아보고, 암세포의 증식에 관여하는 Akt의 활성과 종양 억제유전자인 p53의 신호경로를 규명하고자 하였다. 그 결과, 커큐민과 EGCG를 처리했을 때 HCT116 세포의 증식이 억제되었고, 암세포에서 apoptosis 효과가 나타남을 확인하였다. 동일한 조건에서 Western blotting을 실시했을 때 Akt의 활성은 감소하였으며 p53의 발현은 증가하였다. 또한 Akt의 저해제인 LY294002를 처리했을 때 암세포의 증식이 더욱 강하게 억제되었으며, p53의 발현은 더욱 강하게 증가하는 것으로 나타났다. 따라서 HCT116 세포에서 커큐민과 EGCG 처리에 의한 암세포의 증식 억제 및 apoptosis는 p53의 발현이 증가함에 따라 유도되며, 이러한 p53의 발현 증가는 Akt 신호경로를 저해함으로써 일어난다는 것을 확인하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권7호
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• pp.2645-2651
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• 2015

Background: The phosphatidylinositol 3'-kinase/Akt (PI3K/Akt) pathway is a key regulator for HER2-overexpressing breast cancer, but data about whether activation of PI3K/Akt is associated with poor prognosis and resistance to trastuzumab therapy is controversial. In this study we investigated predictive and prognostic significance of expression of p27, Akt, PTEN and PI3K, which are components of the PI3K/Akt signaling pathway, in HER2-positive metastatic breast cancer (MBC), retrospectively. Materials and Methods: Fifty-four HER2-positive MBC patients who had received first-line trastuzumab-based therapy were recruited for the study group. All of the patient's breast tissue samples were examined for p27 and Akt expression. In addition, twenty-five patients with sufficient amount of tumor tissue were also examined for PTEN and PI3K expression. p27, Akt, PTEN and PI3K were evaluated by immunohistochemistry and their relationship with patient demographic features, tumor characteristics, response to trastuzumab-based treatment and survival outcomes were analyzed. Results: p27, Akt, PTEN and PI3K were positive in 25.9%, 70.4%, 24% and 96% of the cases, respectively. Nomne were significantly associated with response to trastuzumab and time to progression (TTP). A trend toward statistical significance for longer overall survival (OS) was found for PTEN-positive patients (p=0.058); there was no significant relationship between the other immunohistochemical variables and OS. When we analyzed groups regarding co-expression, the PTEN-negative/Akt-negative group had a significantly lower objective response rate (ORR) (20% vs 80%, p=0.023) and the PTEN-negative/p27-negative and PTEN-negative/Akt-negative groups had significantly lower median OS compared to other patients (26.4 months vs 76.1 months, p=0.005 and 25.6 months vs 52.0 months, p=0.007, respectively). Conclusions: p27, Akt, PTEN and PI3K expression is not statistically significantly associated with ORR, TTP and OS, individually. However, the combined evaluation of p27, Akt and PTEN could be helpful to predict the response to trastuzumab-based therapy and prognosis in HER2-positive MBC.

• Journal of Nutrition and Health
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• 제37권1호
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• pp.31-37
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• 2004

Curcumin, a natural compound extracted from rhizomes of Curcuma longa, has been shown to possess potent anti-inflammatory and anti-tumor activity. The mechanism by which curcumin initiates apoptosis remains poorly understood. In this study, we investigated the effects of curcumin on caspase-3 activity and protein expression of procaspase-3, Bcl-2, Bax, total Akt and phosphorylated Akt in SW480 human colon cancer cell. We cultured SW480 cells in the presence of various concentrations (0, 10, 20 or 30 uM) of curcumin. Curcumin inhibited colon cancer cell growth in a dose-dependent manner (p < 0.05). Caspase-3 activity was significantly increased dose-dependently in cells treated with curcumin (p < 0.05), concisely procaspase-3 expression was significantly decreased. Bcl-2 levels were decreased dose-dependently in cells treated with curcumin (p < 0.05), but Ben remained unchanged. In addition, phosphorylated Akt levels and total Akt levels were markedly lower in cells treated with 20 uM of curcumin treatment (p < 0.05), In conclusion, we have shown that curcumin inhibits cell growth and induces apoptosis in SW480 human colon cancer cell lines via Akt signal pathway.

• Journal of Ginseng Research
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• 제39권1호
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• pp.69-75
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• 2015

Background: Ginseng has been shown to exert antistress effects both in vitro and in vivo. However, the effects of ginseng on stress in brain cells are not well understood. This study investigated how Korean Red Ginseng (KRG) controls hydrogen peroxide-induced apoptosis via regulation of phosphatidylinositol-3 kinase (PI3K)/Akt and estrogen receptor (ER)-${\beta}$ signaling. Methods: Human neuroblastoma SK-N-SH cells were pretreated with KRG and subsequently exposed to $H_2O_2$. The ability of KRG to inhibit oxidative stress-induced apoptosis was assessed in MTT cytotoxicity assays. Apoptotic protein expression was examined byWestern blot analysis. The roles of ER-${\beta}$, PI3K, and p-Akt signaling in KRG regulation of apoptosis were studied using small interfering RNAs and/or target antagonists. Results: Pretreating SK-N-SH cells with KRG decreased expression of the proapoptotic proteins p-p53 and caspase-3, but increased expression of the antiapoptotic protein BCL2. KRG pretreatment was also associated with increased ER-${\beta}$, PI3K, and p-Akt expression. Conversely, ER-${\beta}$ inhibition with small interfering RNA or inhibitor treatment increased p-p53 and caspase-3 levels, but decreased BCL2, PI3K, and p-Akt expression. Moreover, inhibition of PI3K/Akt signaling diminished p-p53 and caspase-3 levels, but increased BCL2 expression. Conclusion: Collectively, the data indicate that KRG represses oxidative stress-induced apoptosis by enhancing PI3K/Akt signaling via upregulation of ER-${\beta}$ expression.

• Journal of Ginseng Research
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• 제43권3호
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• pp.394-401
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• 2019

Background: Ginsenoside Rb1, a triterpene saponin, is derived from the Panax ginseng root and has potent antiinflammatory activity. In this study, we determined if Rb1 can increase macrophage phagocytosis and elucidated the underlying mechanisms. Methods: To measure macrophage phagocytosis, mouse peritoneal macrophages or RAW 264.7 cells were cultured with fluorescein isothiocyanate-conjugated Escherichia coli, and the phagocytic index was determined by flow cytometry. Western blot analyses were performed. Results: Ginsenoside Rb1 increased macrophage phagocytosis and phosphorylation of p38 mitogenactivated protein kinase (MAPK), but inhibition of p38 MAPK activity with SB203580 decreased the phagocytic ability of macrophages. Rb1 also increased Akt phosphorylation, which was suppressed by LY294002, a phosphoinositide 3-kinase inhibitor. Rb1-induced Akt phosphorylation was inhibited by SB203580, (5Z)-7-oxozeaenol, and small-interfering RNA (siRNA)-mediated knockdown of $p38{\alpha}$ MAPK in macrophages. However, Rb1-induced p38 MAPK phosphorylation was not blocked by LY294002 or siRNA-mediated knockdown of Akt. The inhibition of Akt activation with siRNA or LY294002 also inhibited the Rb1-induced increase in phagocytosis. Rb1 increased macrophage phagocytosis of IgG-opsonized beads but not unopsonized beads. The phosphorylation of p21 activated kinase 1/2 and actin polymerization induced by IgG-opsonized beads and Rb1 were inhibited by SB203580 and LY294002. Intraperitoneal injection of Rb1 increased phosphorylation of p38 MAPK and Akt and the phagocytosis of bacteria in bronchoalveolar cells. Conclusion: These results suggest that ginsenoside Rb1 enhances the phagocytic capacity of macrophages for bacteria via activation of the p38/Akt pathway. Rb1 may be a useful pharmacological adjuvant for the treatment of bacterial infections in clinically relevant conditions.

• The Korean Journal of Physiology and Pharmacology
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• 제10권3호
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• pp.123-129
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• 2006

In several experimental models, estrogens protect neurons against ischemic insults. However, the recent clinical studies of hormone replacement showed negative results to prevent stroke. Therefore, optimal models to study estrogen replacement for neuroprotection are needed before its clinical ap-plication. Organotypic hippocampal slice under oxygen-glucose deprivation (OGD) has been established as a model of cerebral ischemia and has advantages to study drug effects. We investigated whether estrogen protected CAI neurons and affected activation of Akt (pAkt) in CAI region under OGD. Thus, rat hippocampal slices on day 7 of culture were treated with $17-{\beta}$ estradiol (E, 1 nM) for 7 days before 30 min OGD, and cell death of CAI neurons was quantified by propidium iodide (PI) staining and expression of pAkt was studied by Western blot and immunofluorescence. PI intensity in slices treated with E was significantly reduced 72 hour after OGD compared to that of non-treated slices (p < 0.05). E pretreatment also increased the expression of pAkt 72 hour after OGD compared to that of no treatment (p<0.01). These data suggest that estrogen pretreatment may rescue neurons from ischemic insults through the activation of Akt and also indicate that our model would be a useful alternative method to study the mechanisms and effects of estrogen replacement treatment for neuroprotection.

• 대한본초학회지
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• 제31권1호
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• pp.1-5
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• 2016

Objectives : The purpose of this study was to investigate inhibitory effects of steamed Polygonatum odoratum extract (POE) on insulin resistance in rat skeletal muscle cells, L6 cells.Methods : Polygonatum odoratum (P. odoratum) extract was extracted with ethyl acetate. Activity of α-glucosidase in POE was measured for blood glucose regulation. MTT assay was examined for cell toxicity. Western blot analysis for measurement of adiponectine, peroxisome proliferator-activated receptorγ (PPARγ), insulin receptor substrate (IRS), glucose transporter 4 (Glut-4) and phosphorylation of serine/threonine-specific protein kinase (Akt) expressions were performed. Akt signaling pathway were analyzed with LY294002, which is a specific PI3K/Akt inhibitor.Results : The results revealed that POE inhibited α-glucosidase activity. Treatment of POE in L6 cells inhibited the differentiation of L6 cells compared to those of vehicl control. Additionally, protein expressions of adiponectine, PPARγ, IRS and Glut-4 were significantly regulated compared to those of vehicle control (p < 0.05), respectively. Futhermore, phosphorylation of Akt was increased in L6 cells treated with POE compared to that of vehicle control (p < 0.05). pAkt expression was significantly accentuated with Akt inhibitor (LY294002).Conclusions : These results suggest that POE may have potential as a natural agent for prevention/improvement of diabetes, especially, regulation of blood glucose. Therefore, further additional study should be conducted to elucidate in depth the pharmaceutical efficacy of these.

• 한국식품영양과학회지
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• 제46권4호
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• pp.417-425
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• 2017

벌사상자는 여성의 생식기 질환이나 화농성 피부염에 주로 사용되어온 한약재로, 최근 들어 암과 관련된 연구가 많이 이루어짐에 따라 벌사상자의 항암 효과에 대한 관심이 높아지고 있다. 벌사상자의 대표적인 성분인 osthole, xanthotoxol 등은 벤젠고리 화합물로 에탄올과 같은 유기용매에 잘 용해된다. 이에 따라 본 연구에서는 AGS 위암세포에서 벌사상자 에탄올 추출물(CME)에 대한 세포주기 정지 유도 효과를 확인하고자 하였다. CME 처리에 의한 AGS 위암세포의 증식 억제 유도 효과 및 세포독성 효과를 확인하기 위하여 MTT assay와 LDH release assay를 실시한 결과, 농도 및 시간 의존적으로 세포생존율이 감소하였으며, 농도 의존적인 세포독성 효과를 확인하였다. 또한, CME의 농도가 증가할수록 AGS 위암세포의 형태학적 변화가 관찰되었다. 이러한 세포증식 억제 유도 효과가 세포주기 정지에 의한 것인지 확인하기 위하여 CME를 농도별로 24시간 동안 처리한 후 세포주기를 측정하였다. 그 결과 G1기의 세포가 농도 의존적으로 증가함을 확인하였다. 그리고 CME의 처리가 세포주기와 관련된 단백질에 미치는 영향을 알아보기 위하여 western blot analysis를 실시하여 G1기 세포주기 정지와 관련된 신호 단백질들의 발현 변화를 확인하였다. 그 결과 CME의 처리가 세포 증식과 분열에 중요한 역할을 하는 p-Akt와 p-GSK-$3{\beta}$의 발현을 저해하는 것을 확인하였고, 이에 따라 p53의 발현과 활성이 증가하여 p21의 발현이 증가함을 확인하였다. 또한, p21의 증가에 따른 cyclin E의 발현 감소와 CDK2의 비활성화 상태인 p-CDK(T14), p-CDK(Y15)의 발현 증가를 확인하였다. 이와 같은 CME의 세포주기 억제 유도 효과가 일어나는 신호경로를 확인하기 위하여 LY294002(PI3K/Akt 저해제), BIO(GSK-$3{\beta}$ 저해제), Pifithrin-${\alpha}$(p53 저해제)를 CME와 각각 또는 병행 처리한 후 MTT assay, 세포주기 측정, western blot analysis를 진행하였다. 그 결과 LY294002의 처리는 CME 처리군과 유사하게 세포생존율을 저해시키고 G1기 정지를 유도했으며, 세포주기 단백질을 조절하였다. 또한, GSK-$3{\beta}$와 p53 저해제를 처리하였을 때 CME를 병행 처리했음에도 불구하고 세포증식 억제나 G1기 정지와 같은 항암 효과가 나타나지 않았으며, 관련 신호경로 단백질의 변화도 관찰되지 않았다. 이러한 결과는 CME의 처리가 Akt/GSK-$3{\beta}$/p53 신호경로를 조절하여 cyclin E의 발현을 감소시키고 CDK2의 활성을 억제함으로써 G1기 세포주기 정지를 유도함을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제29권8호
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• pp.1230-1239
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• 2019

Scutellaria baicalensis Georgi has been widely used in China for treatment of various diseases. This study investigated the effect of Scutellaria baicalensis Georgi extracts (SBE) against Coxsackievirus B3 (CVB3)-induced myocarditis in vitro and in vivo. In vitro, Hela cells and primary myocardial cells were infected with CVB3 and treated with SBE ($50-800{\mu}g/ml$) and ribavirin ($200{\mu}M$) for 48 h and then determined by CCK8 assay. Real-time PCR and western blotting assays were performed. In vivo, a myocarditis model was induced in male BALB/c mice by injecting CVB3 suspension intraperitoneally for three times, followed by treatment with SBE (400 and 200 mg/kg) and ribavirin (100 mg/kg) for 28 days. SBE ameliorated the cytotoxicity of CVB3 in Hela cells, especially at $400{\mu}g/ml$ (39.93% vs 65.67%, p < 0.05) without influencing cell growth and also significantly reduced CVB3 replication in primary myocardial cells. The levels of AKT, ERK, and p38 were increased after CVB3 infection. SBE could downregulate the expressions of AKT and p38. In vivo, the mortality rate from CVB3 reached to 66.67%, while 10.00% and 23.33% of this came after 400 and 200 mg/kg SBE treatment, respectively (p < 0.05). The CVB3 replication was obviously reduced after SBE administration from day 5. Similarly, the levels of AKT, ERK, and p38 mRNAs and proteins were increased, and SBE suppressed the expression of AKT and p38. Our study indicates that SBE is a promising potent antiviral agent against CVB3-induced myocarditis by inhibition of virus replication via depressing AKT and p38 expressions.

• The Korean Journal of Physiology and Pharmacology
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• 제24권5호
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• pp.423-431
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• 2020

This study aimed to evaluate the effect of curcumin on brain hypoxic-ischemic (HI) damage in neonatal rats and whether the phosphoinositide 3-kinase (PI3K)/Akt/vascular endothelial growth factor (VEGF) signaling pathway is involved. Brain HI damage models were established in neonatal rats, which received the following treatments: curcumin by intraperitoneal injection before injury, insulin-like growth factor 1 (IGF-1) by subcutaneous injection after injury, and VEGF by intracerebroventricular injection after injury. This was followed by neurological evaluation, hemodynamic measurements, histopathological assessment, TUNEL assay, flow cytometry, and western blotting to assess the expression of p-PI3K, PI3K, p-Akt, Akt, and VEGF. Compared with rats that underwent sham operation, rats with brain HI damage showed remarkably increased neurological deficits, reduced right blood flow volume, elevated blood viscosity and haematocrit, and aggravated cell damage and apoptosis; these injuries were significantly improved by curcumin pretreatment. Meanwhile, brain HI damage induced the overexpression of p-PI3K, p-Akt, and VEGF, while curcumin pretreatment inhibited the expression of these proteins. In addition, IGF-1 treatment rescued the curcumin-induced down-regulated expression of p-PI3K, p-Akt, and VEGF, and VEGF overexpression counteracted the inhibitory effect of curcumin on brain HI damage. Overall, pretreatment with curcumin protected against brain HI damage by targeting VEGF via the PI3K/Akt signaling pathway in neonatal rats.