• 한국식품영양과학회지
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• 제42권8호
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• pp.1197-1203
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• 2013

본 연구는 2주간의 지구성 운동과 ginsenoside $Rb_1$이 쥐골격근의 AMPK insulin signaling($tAMPK{\alpha}$, $pAMPK{\alpha}$ $Thr^{172}$)과 PI3K insulin signaling pathway(pIRS-1 $Tyr^{612}$, PI3K $p^{85}$, pAkt $Ser^{473}$) 발현 및 glucose uptake에 미치는 영향을 분석하였다. 골격근내 glucose uptake에서는 비교집단과 비교하여 운동집단(59.4%), $Rb_1$집단(70.5%) $Rb_1/Ex$집단(58.6%)에서 유의하게 증가하였다. 2주간의 지구성 운동과 ginsenoside $Rb_1$이 AMPK insulin signaling pathway에 미치는 효과를 조사한 결과 비교집단에 비해 $AMPK{\alpha}$(Ex, 28.6%; $Rb_1$, 28.5%; $Rb_1/Ex$, 29.8%), $pAMPK{\alpha}$ $Thr^{172}$(Ex, 35.1%; $Rb_1$, 35.3%; $Rb_1/Ex$, 30.9%)의 발현이 유의하게 증가한 것을 알 수 있었다. 2주간의 지구성 운동과 ginsenoside $Rb_1$이 PI3K insulin signaling pathway에 미치는 효과를 알아본 결과 비교집단과 비교하여 IRS-1, PI3K $p^{85}$에서는 유의한 차이가 없었으나 pAkt $Ser^{473}$은 $Rb_1$ 집단에서 유의하게 증가한 것을 알 수 있었다. 이상의 결과를 종합해 볼 때, ginsenoside $Rb_1$은 운동과 더불어 근육 세포내 AMPK의 활성화와 근육 내 glucose uptake를 증가시켜 제2형 당뇨병 예방과 치료에 효과가 있을 것으로 생각된다. 그러나 본 연구의 결과로 PI3K insulin signaling pathway의 항당뇨 효과는 설명하기는 부족하다고 판단되며 추후 본 연구의 결과를 기초로 ginsenoside $Rb_1$의 농도, 처치시간, 처치방법을 고려한 후속 연구가 필요할 것으로 생각된다.

• The Korean Journal of Physiology and Pharmacology
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• 제25권2호
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• pp.147-157
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• 2021

Coronary microembolization (CME) is associated with cardiomyocyte apoptosis and cardiac dysfunction. Puerarin confers protection against multiple cardiovascular diseases, but its effects and specific mechanisms on CME are not fully known. Hence, our study investigated whether puerarin pretreatment could alleviate cardiomyocyte apoptosis and improve cardiac function following CME. The molecular mechanism associated was also explored. A total of 48 Sprague-Dawley rats were randomly divided into CME, CME + Puerarin (CME + Pue), sham, and sham + Puerarin (sham + Pue) groups (with 12 rats per group). A CME model was established in CME and CME + Pue groups by injecting 42 ㎛ microspheres into the left ventricle of rats. Rats in the CME + Pue and sham + Pue groups were intraperitoneally injected with puerarin at 120 mg/kg daily for 7 days before operation. Cardiac function, myocardial histopathology, and cardiomyocyte apoptosis index were determined via cardiac ultrasound, hematoxylin-eosin (H&E) and hematoxylin-basic fuchsin-picric acid (HBFP) stainings, and TdT-mediated dUTP nick-end labeling (TUNEL) staining, respectively. Western blotting was used to measure protein expression related to the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) pathway. We found that, puerarin significantly ameliorated cardiac dysfunction after CME, attenuated myocardial infarct size, and reduced myocardial apoptotic index. Besides, puerarin inhibited cardiomyocyte apoptosis, as revealed by decreased Bax and cleaved caspase-3, and up-regulated Bcl-2 and PI3K/Akt/GSK-3β pathway related proteins. Collectively, puerarin can inhibit cardiomyocyte apoptosis and thus attenuate myocardial injury caused by CME. Mechanistically, these effects may be achieved through activation of the PI3K/Akt/GSK-3β pathway.

• Genomics & Informatics
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• 제20권1호
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• pp.7.1-7.13
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• 2022

2-Methoxy-1,4-naphthoquinone (MNQ) has been shown to cause cytotoxic towards various cancer cell lines. This study is designed to investigate the regulatory effect of MNQ on the key cancer genes in mitogen-activated protein kinase, phosphoinositide 3-kinase, and nuclear factor κB signaling pathways. The expression levels of the genes were compared at different time point using polymerase chain reaction arrays and Ingenuity Pathway Analysis was performed to identify gene networks that are most significant to key cancer genes. A total of 43 differentially expressed genes were identified with 21 up-regulated and 22 down-regulated genes. Up-regulated genes were involved in apoptosis, cell cycle and act as tumor suppressor while down-regulated genes were involved in anti-apoptosis, angiogenesis, cell cycle and act as transcription factor as well as proto-oncogenes. MNQ exhibited multiple regulatory effects on the cancer key genes that targeting at cell proliferation, cell differentiation, cell transformation, apoptosis, reduce inflammatory responses, inhibits angiogenesis and metastasis.

• 동의생리병리학회지
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• 제23권1호
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• pp.199-205
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• 2009

It is unclear whether Fructus ligustri Lucidi (FLL) extract anti-proliferative effect in human glioma cells. The present study was therefore undertaken to examine the effect of FLL on cell viability and to determine the underlying mechanism in A172 human glioma cells. Cell viability and cell death were estimated by MTT assay and trypan blue exclusion assay, respectively. Apoptosis was measured by Annexin-V binding assay and cell cycle analysis. Activation of kinases and caspase-3 was estimated by Western blot analysis. FLL resulted in apoptotic cell death in a dose- and time-dependent manner. FLL-induced cell death was not associated with reactive oxygen species generation. Western blot analysis showed that FLL treatment caused down-regulation of PI3K/Akt pathway, but not ERK. The PI3K/Akt inhibitor LY984002 sensitized the FLL-induced cell death and overexpression of Akt prevented the cell death. FLL induced caspase-3 activation and the FLL-induced cell death was prevented by caspase inhibitors. These findings indicate that FLL results in a caspase-dependent cell death through a P13K/Akt pathway in human glioma cells. These data suggest that FLL may serve as a potential therapeutic agent for malignant human gliomas.

• Biomolecules & Therapeutics
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• 제31권3호
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• pp.319-329
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• 2023

Resistance to hypomethylating agents (HMAs) in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) is a concerning problem. Polo-like kinase 1 (PLK1) is a key cell cycle modulator and is known to be associated with an activation of the PI3K pathway, which is related to the stabilization of DNA methyltransferase 1 (DNMT1), a target of HMAs. We investigated the effects of volasertib on HMA-resistant cell lines (MOLM/AZA-1 and MOLM/DEC-5) derived from MOLM-13, and bone marrow (BM) samples obtained from patients with MDS (BM blasts >5%) or AML evolved from MDS (MDS/AML). Volasertib effectively inhibited the proliferation of HMA-resistant cells with suppression of DNMTs and PI3K/AKT/mTOR and ERK pathways. Volasertib also showed significant inhibitory effects against primary BM cells from patients with MDS or MDS/AML, and the effects of volasertib inversely correlated with DNMT3B expression. The DNMT3B-overexpressed AML cells showed primary resistance to volasertib treatment. Our data suggest that volasertib has a potential role in overcoming HMA resistance in patients with MDS and MDS/AML by suppressing the expression of DNMT3 enzymes and PI3K/AKT/mTOR and ERK pathways. We also found that DNMT3B overexpression might be associated with resistance to volasertib.

• Nutrition Research and Practice
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• 제16권3호
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• pp.330-343
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• 2022

BACKGROUND/OBJECTIVES: Zanthoxylum schinifolium is traditionally used as a spice for cooking in East Asian countries. This study was undertaken to evaluate the anti-proliferative potential of ethanol extracts of Z. schinifolium leaves (EEZS) against human bladder cancer T24 cells. MATERIALS/METHODS: Subsequent to measuring the cytotoxicity of EEZS, the anti-cancer activity was measured by assessing apoptosis induction, reactive oxygen species (ROS) generation, and mitochondrial membrane potential (MMP). In addition, we determined the underlying mechanism of EEZS-induced apoptosis through various assays, including Western blot analysis. RESULTS: EEZS treatment concentration-dependently inhibited T24 cell survival, which is associated with apoptosis induction. Exposure to EEZS induced the expression of Fas and Fas-ligand, activated caspases, and subsequently resulted to cleavage of poly (ADP-ribose) polymerase. EEZS also enhanced the expression of cytochrome c in the cytoplasm by suppressing MMP, following increase in the ratio of Bax:Bcl-2 expression and truncation of Bid. However, EEZS-mediated growth inhibition and apoptosis were significantly diminished by a pan-caspase inhibitor. Moreover, EEZS inhibited activation of the phosphoinositide 3-kinase (PI3K)/Akt pathway, and the apoptosis-inducing potential of EEZS was promoted in the presence of PI3K/Akt inhibitor. In addition, EEZS enhanced the production of ROS, whereas N-acetyl cysteine (NAC), a ROS scavenger, markedly suppressed growth inhibition and inactivation of the PI3K/Akt signaling pathway induced by EEZS. Furthermore, NAC significantly attenuated the EEZS-induced apoptosis and reduction of cell viability. CONCLUSIONS: Taken together, our results indicate that exposure to EEZS exhibits anti-cancer activity in T24 bladder cancer cells through ROS-dependent induction of apoptosis and inactivation of the PI3K/Akt signaling pathway.

• 동의생리병리학회지
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• 제23권2호
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• pp.416-425
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• 2009

Angiogenesis is important for promoting cardiovascular disease, wound healing, and tissue regeneration. We here investigated the pharmacological effects of Korea red ginseng water extract (KRGE) on angiogenesis and its underlying signal mechanism. This study showed that KRGE increased in vitro proliferation, migration, and tube formation of human umbilical endothelial cells, as well as stimulated in vivo angiogenesis. KRGE-induced angiogenesis was accompanied by phosphorylation of ERK1/2, Akt, and endothelial nitric oxide synthase (eNOS) as well as an increase in NO production. Inhibition of PI3K activity by wortmannin completely inhibited KRGE-induced angiogenesis and phosphorylation of Akt, ERK1/2, and eNOS, indicating that PI3K/Akt activation is an upstream event of KRGE-mediated angiogenic pathway. The MEK inhibitor PD98059 completely blocked KRGE-induced angiogenesis and ERK phosphorylation without affecting Akt and eNOS activation. However, the eNOS inhibitor NMA effectively inhibited tube formation, but partially blocked proliferation and migration as well as ERK phosphorylation without altering Akt and eNOS activation, revealing that eNOS/NO pathway is in part involved in ERK1/2 activation. This study first demonstrated the critical involvement of both ERK1/2 and eNOS activation in KRGE-induced angiogenesis, which lie on downstream of PI3K/Akt. Thus, these results indicate that KRGE requires activation of both the PI3K/Akt-dependent ERK1/2 and eNOS signal pathways and their cross-talk for its full angiogenic activity.

• BMB Reports
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• 제32권2호
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• pp.196-202
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• 1999

The existence of the Ras-independent signal transduction pathway of insulin leading to DNA synthesis was investigated in Rat-1 fibroblasts overexpressing human insulin receptor (HIRc-B) using the single-cell microinjection technique. Microinjection of a dominant-negative mutant $Ras^{N17}$ protein into quiescent HIRc-B cells inhibited the DNA synthesis stimulated by insulin. Microinjection of oncogenic H-$Ras^{V12}$ protein ($H-Ras^{V12}$) (0.1 mg/ml) induced DNA synthesis by 35%, whereas that of control-injected IgG was induced by 20%. When the marginal amount of oncogenic H-$Ras^{V12}$ protein was coinjected with a dominant-negative mutant of the H-Ras protein ($Ras^{N17}$), DNA synthesis was 35% and 74% in the absence and presence of insulin, respectively. This full recovery of DNA synthesis by insulin suggests the existence of the Ras-independent pathway. The same recovery was observed in the cells coinjected with either H-$Ras^{V12}$ plus H-$Ras^{N17}$ plus SH2 domain of the p85 subunit of PI3-kinase ($p85^{SH2-N}$) or H-$Ras^{V12}$ plus H-$Ras^{N17}$ plus interfering anti-Shc antibody. When co-injected with a dominant-negative H-$Ras^{N17}$, the DNA synthesis induced by the Ras-independent pathway was blocked. These results indicate that the Ras-independent pathway of insulin leading to DNA synthesis exists, bypassing the p85 of PI3-kinase and Shc protein, and requires Rac1 protein.

• 동의생리병리학회지
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• 제21권1호
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• pp.86-92
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• 2007

Hibiscus sabdariffa L., a tropical beverage material, is used commonly as in folk medicine against hypertension, pyrexia, inflammation, liver disorders, and obesity. However, the mechanism by which Hibiscus sabdariffa L. modulates adipogenic differentiation is remained to be elusive. This report was designed to investigate the inhibitory effect of Hibiscus extract on insulin signaling pathway during adipocyte differentiation in 3T3-L1 preadipocytes. 3T3-L1 preadipocytes were differentiated with isobutylmethylxanthine, dexamethasone, and insulin (MDI) and followed by the addition of Hibiscus extract. Treatment with Hibiscus resulted in a decrease of lipid droplet accumulation, which was suppressed by PI-3 kinase inhibitor wortmannin in 3T3-L1 preadipocytes. Also, Hibiscus extract markedly attenuated the mRNA expression of adipogenic transcriptional factor PPAR${\gamma}$ and adipogenic hormon Leptin during adipogenesis. However, it did not affect the expression of adiponectin in 3T3-L1 preadipocytes differentiated with MDI mixture. Furthermore, Adipogenic differentiation by MDI mixture increased the phosphorylation and expression of PI3-Kinase and Akt in 3T3 preadipocytes, which was markedly suppressed by Hibiscus extract treatment. Taken together, our results suggest that Hibiscus extract suppressed the adipogenic differentiation of 3T3 preadipocytes through activation of PI3-Kinase and Akt signaling pathway.

• Fisheries and Aquatic Sciences
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• 제26권2호
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• pp.133-144
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• 2023

Auranofin is a US Food and Drug Administration (FDA)-approved anti-arthritis medication that functions as a thioredoxin reductase inhibitor. Spermidine, a polyamine present in marine algae, can exert various physiological functions. Herein, we examined the synergistic anticancer activity of auranofin and spermidine in hepatocellular carcinoma (HCC). Combined treatment with auranofin and spermidine suppressed cell viability more efficiently than either treatment alone in HCC Hep3B cells. The isobologram plotted by calculating the half maximal inhibitory concentration (IC₅₀) values of each drug indicated that the two drugs exhibited a synergistic effect. Based on the analysis of annexin V and cell cycle distribution, auranofin and spermidine markedly induced apoptosis in Hep3B cells. Moreover, auranofin and spermidine increased mitochondria-mediated apoptosis by promoting mitochondrial membrane potential (Δψm) loss. Auranofin and spermidine significantly increased reactive oxygen species (ROS) production in Hep3B cells, and the blocking ROS suppressed apoptosis induced by spermidine and auranofin. In addition, auranofin and spermidine reduced the expression of phosphorylated phosphatidylinositol-3 kinase (PI3K) and protein kinase B (Akt), and PI3K inhibitor accelerated auranofin- and spermidine-induced apoptosis. Using ROS scavenger and PI3K inhibitor, we revealed that ROS acts upstream of auranofin- and spermidine-induced apoptosis. Collectively, our study suggests that combination treatment with auranofin and spermidine could afford synergistic anticancer activity via ROS overproduction and reduced PI3K/Akt signaling pathway.