• 한국발생생물학회지:발생과생식
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• 제15권2호
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• pp.179-185
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• 2011

콩이나 적포도주의 식물성 에스트로겐(phytoestrogen)은 건강에 부정적이기보다는 긍정적인 효과를 갖는 것으로 알려져 있는데, 특히 콩류 섭취는 유방암이나 골다공증, 그리고 심혈관계 질환 예방과 높은 상관관계가 있는 것으로 보인다. 그러나 콩류, 특히 그 주성분인 genistein(GS)이 상기한 긍정적인 효과 외에도 여성의 생식계에 잠재적으로 부정적인 영향을 미칠 가능성에 대한 의문이 계속되어왔다. 선행 연구에서 본 연구자들은 사춘기 전에 genistein(GS)을 경구 투여했을 때 암컷 흰쥐의 생식계가 활성화되어 사춘기 개시가 조기에 유도되고, 암컷 성체에 GS를 뇌실내로 미세주입했을 때 kisspeptin-GnRH 뉴런회로 활성화가 일어남을 관찰하였다. 본 연구에서는 사춘기 전 암컷 흰쥐에서의 시상하부 특이적인 GS 투여 효과와 이에 관여하는 에스트로겐 수용체 아형($ER{\alpha}$과 $ER{\beta}$)을 조사하였다. 사춘기 전암컷 흰쥐(SD strain, PND 30)를 마취시킨 후 GS(3.4 ${\mu}g$/animal)를 1회 뇌실내로 미세 주입하고, 2시간 후 희생시켰다. 시상하부내 생식조절 유전자 발현을 조사하기 위해, RNA를 추출한 후 semi-quantitative reverse transcription polymerasechain reaction(RT-PCR)을 시행하였다. GS 투여는 KiSS-1 유전자 발현의 상위조절자인 mTOR(1:$0.361{\pm}0.058$ AU, p<0.001)발현을 유의하게 감소시켰고, GnRH 분비의 상위조절자인 GAD67(1:$1.285{\pm}0.099$ AU, p<0.05) 발현을 유의하게 증가시켰다. GS 투여는 KiSS-1(1:$1.458{\pm}0.078$ AU, p<0.001) mRNA 수준을 유의하게 증가시켰지만, kisspeptin 수용체인 GPR-54(1:$1.29{\pm}0.08$ AU) mRNA 수준은 변화가 없었고, GnRH(1:$0.379{\pm}0.196$ AU, p<0.05)의 경우는 유의하게 감소시켰다. GS투여군에서 $ER{\alpha}$(1:$1.180{\pm}0.390$ AU) 발현은 대조군 대비 차이가 없었지만, $ER{\beta}$(1:$4.209{\pm}0.796$ AU, p<0.01) 발현은 유의하게 증가했다. 본 연구결과는 사춘기 전 암컷 흰쥐에서 GS의 단기 노출이 시상하부의 GnRH 조절시스템을 직접 변화시킴을 보여준 것으로, 이러한 GS의 시상하부 특이적 효과에 $ER{\beta}$ 경로가 관여함을 강력히 시사한다. 이는 잘 알려진 $ER{\beta}$ 경로를 매개로 하는 GS의 유방암 억제 효과와 일치한다.

• 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.

• Molecules and Cells
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• 제38권2호
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• pp.138-144
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• 2015

Raloxifene is a selective estrogen receptor modulator (SERM) that binds to the estrogen receptor (ER), and exhibits potent anti-tumor and autophagy-inducing effects in breast cancer cells. However, the mechanism of raloxifene-induced cell death and autophagy is not well-established. So, we analyzed mechanism underlying death and autophagy induced by raloxifene in MCF-7 breast cancer cells. Treatment with raloxifene significantly induced death in MCF-7 cells. Raloxifene accumulated GFP-LC3 puncta and increased the level of autophagic marker proteins, such as LC3-II, BECN1, and ATG12-ATG5 conjugates, indicating activated autophagy. Raloxifene also increased autophagic flux indicators, the cleavage of GFP from GFP-LC3 and only red fluorescence-positive puncta in mRFP-GFP-LC3-expressing cells. An autophagy inhibitor, 3-methyladenine (3-MA), suppressed the level of LC3-II and blocked the formation of GFP-LC3 puncta. Moreover, siRNA targeting BECN1 markedly reversed cell death and the level of LC3-II increased by raloxifene. Besides, raloxifene-induced cell death was not related to cleavage of caspases-7, -9, and PARP. These results indicate that raloxifene activates autophagy-dependent cell death but not apoptosis. Interestingly, raloxifene decreased the level of intracellular adenosine triphosphate (ATP) and activated the AMPK/ULK1 pathway. However it was not suppressed the AKT/mTOR pathway. Addition of ATP decreased the phosphorylation of AMPK as well as the accumulation of LC3-II, finally attenuating raloxifene-induced cell death. Our current study demonstrates that raloxifene induces autophagy via the activation of AMPK by sensing decreases in ATP, and that the overactivation of autophagy promotes cell death and thereby mediates the anti-cancer effects of raloxifene in breast cancer cells.

• Experimental and Molecular Medicine
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• 제50권11호
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• pp.13.1-13.15
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• 2018

Wound healing is delayed in diabetic patients. Increased apoptosis and endothelial progenitor cell (EPC) dysfunction are implicated in delayed diabetic wound healing. Melatonin, a major secretory product of the pineal gland, promotes diabetic wound healing; however, its mechanism of action remains unclear. Here, EPCs were isolated from the bone marrow of mice. Treatment of EPCs with melatonin alleviated advanced glycation end product (AGE)-induced apoptosis and cellular dysfunction. We further examined autophagy flux after melatonin treatment and found increased light chain 3 (LC3) and p62 protein levels in AGE-treated EPCs. However, lysosome-associated membrane protein 2 expression was decreased, indicating that autophagy flux was impaired in EPCs treated with AGEs. We then evaluated autophagy flux after melatonin treatment and found that melatonin increased the LC3 levels, but attenuated the accumulation of p62, suggesting a stimulatory effect of melatonin on autophagy flux. Blockage of autophagy flux by chloroquine partially abolished the protective effects of melatonin, indicating that autophagy flux is involved in the protective effects of melatonin. Furthermore, we found that the AMPK/mTOR signaling pathway is involved in autophagy flux stimulation by melatonin. An in vivo study also illustrated that melatonin treatment ameliorated impaired wound healing in a streptozotocin-induced diabetic wound healing model. Thus, our study shows that melatonin protects EPCs against apoptosis and dysfunction via autophagy flux stimulation and ameliorates impaired wound healing in vivo, providing insight into its mechanism of action in diabetic wound healing.

• 대한한의학방제학회지
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• 제29권2호
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• pp.71-80
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• 2021

Objectives : This study investigated cellular-protective effects of Nardotidis seu Sulculii Concha water extract (NSCE) against oxidative stress induced by arachidonic acid (AA)+iron or tert-butylhydroperoxide (tBHP). Methods : In vitro, MTT assay was assessed for cell viability, and immunoblotting analysis was performed to detect expression of AMP-activated kinase (AMPK) signaling pathway and autophagy related proteins. In vivo, mice were orally administrated with the aqueous extract of NSCE of 500 mg/kg for 3 days, and then injected with CCl₄ 0.5 mg/kg body weight to induce acute damage. The level of liver damage was measured by serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) analysis. Results : Treatment with NSCE inhibited cell death induced by AA+iron and tBHP. NSCE induced the phosphorylation of AMPK, and this compound also induced the phosphorylation of LKB1, an upstream kinase of AMPK, and Acetyl-CoA carboxylase (ACC), a primary downstream target of AMPK. NSCE increased the protein levels of autophagic markers (LC3II and beclin-1) and decreased the phosphorylation of mammalian target of rapamycin (mTOR) and simultaneously increased the phosphorylation of unc-51-like kinase-1 (ULK-1) in time-dependent manner. Conclusions : NSCE has the ability 1) to protect cells against oxidative stress induced by AA+iron or tBHP. NSCE 2) to activate AMP-activated protein kinase (AMPK), and 3) to regulate autophagy, an important regulator in cell survival.

• Biomolecules & Therapeutics
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• 제29권2호
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• pp.211-219
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• 2021

Alopecia is a distressing condition caused by the dysregulation of anagen, catagen, and telogen in the hair cycle. Dermal papilla cells (DPCs) regulate the hair cycle and play important roles in hair growth and regeneration. Myristoleic acid (MA) increases Wnt reporter activity in DPCs. However, the action mechanisms of MA on the stimulation of anagen signaling in DPCs is not known. In this study, we evaluated the effects of MA on anagen-activating signaling pathways in DPCs. MA significantly increased DPC proliferation and stimulated the G2/M phase, accompanied by increasing cyclin A, Cdc2, and cyclin B1. To elucidate the mechanism by which MA promotes DPC proliferation, we evaluated the effect of MA on autophagy and intracellular pathways. MA induced autophagosome formation by decreasing the levels of the phospho-mammalian target of rapamycin (phospho-mTOR) and increasing autophagy-related 7 (Atg7) and microtubule-associated protein 1A/1B-light chain 3II (LC3II). MA also increased the phosphorylation levels of Wnt/β-catenin proteins, such as GSK3β (Ser9) and β-catenin (Ser552 and Ser675). Treatment with XAV939, an inhibitor of the Wnt/β-catenin pathway, attenuated the MA-induced increase in β-catenin nuclear translocation. Moreover, XAV939 reduced MA-induced effects on cell cycle progression, autophagy, and DPC proliferation. On the other hand, MA increased the levels of phospho (Thr202/Tyr204)-extracellular signal regulated kinases (ERK). MA-induced ERK phosphorylation led to changes in the expression levels of Cdc2, Atg7 and LC3II, as well as DPC proliferation. Our results suggest that MA promotes anagen signaling via autophagy and cell cycle progression by activating the Wnt/β-catenin and ERK pathways in DPCs.