• Molecules and Cells
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• 제37권9호
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• pp.699-704
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• 2014

Themetastasis-associated gene 1 (MTA1) oncogene hasbeen suggested to be involved in the regulation of cancer progression. However, there is still no direct evidence that MTA1 regulates cisplatin (CDDP) resistance, as well as cancer stem cell properties. In this study, we found that MTA1 was enriched in CNE1/CDDP cells. Knock down of MTA1 in CNE1/CDDP cells reversed CSCs properties and CDDP resistance. However, ectopic expression of MTA1 in CNE1 cells induced CSCs phenotypes and CDDP insensitivity. Interestingly, ectopic overexpression of MTA1-induced CSCs properties and CDDP resistance were reversed in CNE1 cells after inhibition of PI3K/Akt by LY294002. In addition, MTA1 expression and Akt activity in CNE1/CDDP cells was much higher than that in CNE1 cells. These results suggested that MTA1 may play a critical role in promoting CDDP resistance in NPC cells by regulatingcancer stem cell properties via thePI3K/Akt signaling pathway. Our findings suggested that MTA1 may be a potential target for overcoming CDDP resistance in NPC therapy.

• Journal of Microbiology and Biotechnology
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• 제11권5호
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• pp.825-830
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• 2001

Escherichia coli, which harbored the ars operon from a plasmid pMH12 of Klebsiella oxytoca D12, showed filamentation due to the expression of ars genes in the presence of arsenite. The continued DNA replication in the absence of cell division was revealed, since nucleoids abound with DAPI appeared to be arranged in chains. In contrast to overexpression of arsA, its frame-shift mutant and knock-out mutant lost filamentation in the presence of arsenite, which suggested that ars-induced division block was dependent on expression of arsA. ArsA-induced division inhibition was not a consequence of an inhibition of DNA replication, and the inability of arsenite to induce an SOS response indicated that arsA-mediated division inhibition was dependent on the expression of the gene product encoded by the minB operon. ArsA is a peripheral membrane protein with an ATP-binding domain, which is homologous to MinD that requires ATP-dependent efflux. These results suggested that ArsA could possibly recruit MinC to the membrane and modulate cytoplasmic FtsZ to block assembly at the middle of the cell.

• 동의생리병리학회지
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• 제33권4호
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• pp.191-197
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• 2019

This study aims to evaluate the effects of the root bark of Morus alba (RMA) on the regulation of the Hippo-YAP pathway. Hippo-YAP signaling is a critical regulator in controlling organ size and tissue homeostasis. Hippo, the serine/threonine kinase phosphorylate the LATS. Phosphorylated LATS then phosphorylates and inactivates the YAP and TAZ, which are two closely related transcriptional co-activator. Here we report RMA activates the Hippo signaling, thereby inhibits the YAP/TAZ activity. First, we examine the cytotoxic effects of RMA by MTT assay. RMA was cytotoxic at concentrations higher than $50{\mu}g/ml$ in HEK293A cells. The reporter gene assay was performed to measure the activity of TEAD, a key transcription factor that controls cell growth and proliferation. RMA significantly suppressed the luciferase activity. By phos-taq gel shift assay, and western blotting, we showed that RMA enhanced the phosphorylation of YAP in wild type cells, but not in LATS1/2 knock out cells, which means RMA activates classical Hippo pathway. RMA induced the cytoplasmic sequestration of YAP. RMA also suppressed the mRNA expression of CTGF and CYR61; the two major YAP dependent genes. Taken together, RMA is considered to be a good candidate for proliferative disease such as cancer, by facilitating cell death through activating the Hippo signaling pathway.

• Biomolecules & Therapeutics
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• 제30권4호
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• pp.348-359
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• 2022

Gastric adenocarcinoma is among the top causes of cancer-related death and is one of the most commonly diagnosed carcinomas worldwide. Benzyl isothiocyanate (BITC) has been reported to inhibit the gastric cancer metastasis. In our previous study, BITC induced apoptosis in AGS cells. The purpose of the present study was to investigate the effect of BITC on autophagy mechanism in AGS cells. First, the AGS cells were treated with 5, 10, or 15 μM BITC for 24 h, followed by an analysis of the autophagy mechanism. The expression level of autophagy proteins involved in different steps of autophagy, such as LC3B, p62/SQSTM1, Atg5-Atg12, Beclin1, p-mTOR/mTOR ratio, and class III PI3K was measured in the BITC-treated cells. Lysosomal function was investigated using cathepsin activity and Bafilomycin A1, an autophagy degradation stage inhibitor. Methods including qPCR, western blotting, and immunocytochemistry were employed to detect the protein expression levels. Acridine orange staining and omnicathepsin assay were conducted to analyze the lysosomal function. siRNA transfection was performed to knock down the LC3B gene. BITC reduced the level of autophagy protein such as Beclin 1, class III PI3K, and Atg5-Atg12. BITC also induced lysosomal dysfunction which was shown as reducing cathepsin activity, protein level of cathepsin, and enlargement of acidic vesicle. Overall, the results showed that the BITC-induced AGS cell death mechanism also comprises the inhibition of the cytoprotective autophagy at both initiation and degradation steps.

• Korean Circulation Journal
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• 제53권6호
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• pp.351-366
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• 2023

Along with the development of immunosuppressive drugs, major advances on xenotransplantation were achieved by understanding the immunobiology of xenograft rejection. Most importantly, three predominant carbohydrate antigens on porcine endothelial cells were key elements provoking hyperacute rejection: α1,3-galactose, SDa blood group antigen, and N-glycolylneuraminic acid. Preformed antibodies binding to the porcine major xenoantigen causes complement activation and endothelial cell activation, leading to xenograft injury and intravascular thrombosis. Recent advances in genetic engineering enabled knock-outs of these major xenoantigens, thus producing xenografts with less hyperacute rejection rates. Another milestone in the history of xenotransplantation was the development of co-stimulation blockaded strategy. Unlike allotransplantation, xenotransplantation requires blockade of CD40-CD40L pathway to prevent T-cell dependent B-cell activation and antibody production. In 2010s, advanced genetic engineering of xenograft by inducing the expression of multiple human transgenes became available. So-called 'multi-gene' xenografts expressing human transgenes such as thrombomodulin and endothelial protein C receptor were introduced, which resulted in the reduction of thrombotic events and improvement of xenograft survival. Still, there are many limitations to clinical translation of cardiac xenotransplantation. Along with technical challenges, zoonotic infection and physiological discordances are major obstacles. Social barriers including healthcare costs also need to be addressed. Although there are several remaining obstacles to overcome, xenotransplantation would surely become the novel option for millions of patients with end-stage heart failure who have limited options to traditional therapeutics.

• IMMUNE NETWORK
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• 제20권3호
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• pp.26.1-26.9
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• 2020

Cereblon (CRBN), a negative modulator of AMP-activated protein kinase (AMPK), is highly expressed in the retina. We confirmed the expression of CRBN in ARPE-19 human retinal cells by Western blotting. We also demonstrated that CRBN knock-down (KD) could effectively downregulate IL-6 and MCP-1 protein and gene expression in LPS-stimulated ARPE-19 cells. Additionally, CRBN KD increased the phosphorylation of AMPK/acetylcoenzyme A carboxylase (ACC) and the expression of heme oxygenase-1 (HO-1) in ARPE-19 cells. Furthermore, CRBN KD significantly reduced LPS-induced nuclear translocation of NF-κB p65 and activation of NF-κB promoter activity. However, these processes could be inactivated by compound C (inhibitor of AMPK) and zinc protoporphyrin-1 (ZnPP-1; inhibitor of HO-1). In conclusion, compound C and ZnPP-1 can rescue LPS-induced levels of proinflammatory cytokines (IL-6 and MCP-1) in CRBN KD ARPE-19 cells. Our data demonstrate that CRBN deficiency negatively regulates proinflammatory cytokines via the activation of AMPK/HO-1 in the retina.

• Biomolecules & Therapeutics
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• 제32권5호
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• pp.611-626
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• 2024

Leptin, an adipose tissue-derived hormone, has exhibited the potent hepatotoxic effects. However, the underlying molecular mechanisms are not fully understood. In this study, we have elucidated the mechanisms by which leptin exerts cytotoxic effects in hepatocytes, particularly focusing on the role of interleukin-1β (IL-1β) signaling. Leptin significantly induced maturation and secretion of IL-1β in cultured rat hepatocytes. Interestingly, inhibition of IL-1β signaling by pretreatment with an IL-1 receptor antagonist (IL-1Ra) or gene silencing of type I IL-1 receptor (IL-1R1) markedly abrogated leptin-induced cell cycle arrest. The critical role of IL-1β signaling in leptin-induced cell cycle arrest is mediated via upregulation of p16, which acts as an inhibitor of cyclin-dependent kinase. In addition, leptin-induced apoptotic cell death was relieved by inhibition of IL-1β signaling, as determined by annexin V/7-AAD binding assay. Mechanistically, IL-1β signaling contributes to apoptotic cell death and cell cycle arrest by suppressing AKT and activation of p38 mitogen-activated protein kinase (p38MAPK) signaling pathways. Involvement of IL-1β signaling in cytotoxic effect of leptin was further confirmed in vivo using hepatocyte specific IL-1R1 knock out (IL-1R1 KO) mice. Essentially similar results were obtained in vivo, where leptin administration caused the upregulation of apoptotic markers, dephosphorylation of AKT, and p38MAPK activation were observed in wild type mice liver without significant effects in the livers of IL-1R1 KO mice. Taken together, these results demonstrate that IL-1β signaling critically contributes to leptin-induced cell cycle arrest and apoptosis, at least in part, by modulating p38MAPK and AKT signaling pathways.

• 미생물학회지
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• 제48권2호
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• pp.66-72
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• 2012

Nup188 단백질은 진화적으로 보존된 가장 큰 핵공단백질 중의 하나로 핵공복합체의 inner ring을 구성하는 인자이다. Nup188의 이종상동체인 분열효모 S. pombe의 Nup184 단백질은 영양분이 풍부한 완전배지(YES 배지)에서 정상적인 생장과 mRNA의 핵에서 세포질로의 이동에 필요하다. 본 연구에서는 ${\Delta}nup184$ 결실돌연변이를 YES 배지에서 배양할 때 보이는 생장지체와 mRNA export 결함을 상보하기 위해서 Nup184의 카르복시 부위(아미노산 잔기482에서 1628까지)가 필요함을 알아내었다. 또한 이 부위는 GFP-Nup184 융합단백질이 핵막에 위치하기 위해서도 필요하였다. 이 과정에서 S. pombe GeneDB (Sanger 연구소, 영국)에 등록되어 있는 Nup184의 열린읽기틀 (1564개의 아미노산 잔기로 된 단백질로 예측)이 우리가 얻은 염기서열 데이터에 비해 66개의 아미노산 잔기가 짧다는 것을 발견하였다. 이 카르복시-말단 부위는 Nup184의 기능에 반드시 필요하였다. 이외에도 Nup184 단백질이 세포 안에서 SUMO 변형되어 있음을 보였다.

• Molecules and Cells
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• 제38권2호
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• pp.130-137
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• 2015

MicroRNAs (miRNAs) are small, endogenous RNAs that play important gene-regulatory roles by binding to the imperfectly complementary sequences at the 3'-UTR of mRNAs and directing their gene expression. Here, we first discovered that miR-576-3p was down-regulated in human bladder cancer cell lines compared with the non-malignant cell line. To better characterize the role of miR-576-3p in bladder cancer cells, we over-expressed or down-regulated miR-576-3p in bladder cancer cells by transfecting with chemically synthesized mimic or inhibitor. The overexpression of miR-576-3p remarkably inhibited cell proliferation via G1-phase arrest, and decreased both mRNA and protein levels of cyclin D1 which played a key role in G1/S phase transition. The knock-down of miR-576-3p significantly promoted the proliferation of bladder cancer cells by accelerating the progression of cell cycle and increased the expression of cyclin D1. Moreover, the dual-luciferase reporter assays indicated that miR-576-3p could directly target cyclin D1 through binding its 3'-UTR. All the results demonstrated that miR-576-3p might be a novel suppressor of bladder cancer cell proliferation through targeting cyclin D1.

• 생명과학회지
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• 제25권10호
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• pp.1091-1097
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• 2015

본 논문에서 벼 ascorbate peroxidase (OsAPx1) 유전자의 발현 분석을 Northern과 Western 분석을 통하여 유묘 에서는 뿌리, 정단분열조직(shoot apical meristem, SAM), 잎 보다는 잎집에서 더 많이 발현되는 것을 확인하였다. 성숙된 조직에서는 OsAPx1 유전자가 잎을 제외하고는 뿌리, 줄기, 꽃에서 강하게 발현되었다. 또한 이 OsAPx1 유전자는 벼 곰팡이 병원균인 벼 도열병 및 세균성 병원균인 흰빛잎마름병에도 반응하였고 특히 흥미있게도 OsAPx1 유전자는 식물호르몬에 대해서 서로 다르게 발현 양상을 보였다. 이 유전자는 자스몬산(JA)에 대해서는 강한 발현 을 보였지만 반대로 살리실산(SA) 및 ABA와 같이 처리된 세포에서는 강한 발현 억제를 보였다. 이는 이 유전자가 JA에는 반응하지만 SA와 ABA하고는 서로 길항작용을 하는 것으로 보인다. 근연관계분석을 통하여 OsAPx1유전 자가 애기장대의 AtAPx1 와 거의 유사하여 AtAPx1 결손 라인을 가지고 표현형 조사를 실시하였다. 그 결과, 외부에서 H₂O₂를 처리하였을 때에 O₂^- 와 H₂O₂의 축적이 wild type과 비교하여 AtAPx1 결손 라인에서는 현저히 높았다. 따라서 본 연구를, 통하여 OsAPx1 유전자는 벼에서 산화 환원 균형 유지를 통하여 다양한 세포 분화발달 및 병원균 방어에도 관여하며 이 유전자의 발현은 JA의 신호전달에 의해서 매개되는 것으로 예상이 된다.