• BMB Reports
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• 제53권4호
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• pp.223-228
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• 2020

Dysregulation of histone deacetylase 6 (HDAC6) can lead to the pathologic states and result in the development of various diseases including cancers and inflammatory diseases. The objective of this study was to elucidate the regulatory role of microRNA-22 (miR-22) in HDAC6-mediated expression of pro-inflammatory cytokines in lipopolysaccharide (LPS)-stimulated macrophages. LPS stimulation induced HDAC6 expression, but suppressed miR-22 expression in macrophages, suggesting possible correlation between HDAC6 and miR-22. Luciferase reporter assays revealed that 3'UTR of HDAC6 was a bona fide target site of miR-22. Transfection of miR-22 mimic significantly inhibited LPS-induced HDAC6 expression, while miR-22 inhibitor further increased LPS-induced HDAC6 expression. LPS-induced activation of NF-κB and AP-1 was inhibited by miR-22 mimic, but further increased by miR-22 inhibitor. LPS-induced expression of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 was inhibited by miR-22 mimic, but further increased by miR-22 inhibitor. Taken together, these data provide evidence that miR-22 can downregulate LPS-induced expression of pro-inflammatory cytokines via suppression of NF-κB and AP-1 axis by targeting HDAC6 in macrophages.

• Journal of Gastric Cancer
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• 제16권4호
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• pp.221-229
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• 2016

Purpose: Dysregulated microRNAs (miRNAs) can contribute to cancer development by leading to abnormal proliferation of cells, apoptosis, and differentiation. Although several miRNAs that are related to gastric cancer have been identified, the reported results have been inconsistent. The aim of this study was to determine miRNA expression profiles and validate miRNAs up- and down-regulated in gastric cancer. Materials and Methods: We evaluated 34 primary gastric cancer tissues and paired adjacent nontumorous gastric tissues. Total RNA was extracted, and low-molecular-weight RNAs (<200 nucleotides) were isolated for further analysis. Two pairs of tissues were processed for GeneChip microarray analysis, and the identified up- and down-regulated miRNAs were validated by real-time quantitative polymerase chain reaction (qPCR). Results: In the set of differentially expressed miRNAs, 5 were overexpressed by more than 2 fold, and 5 were reduced by 2 fold or less in gastric cancer tissues compared with normal gastric tissues. Four of these miRNAs (miR-196b-5p, miR-375, miR-483-5p, and miR-486-5p) were then validated by qPCR, and the relative expression levels of 2 miRNAs (miR-196b-5p and miR-375) were significantly different between cancer and normal tissues. Conclusions: Our results revealed that the expression of miR-196b-5p and miR-375 significantly correlates with gastric cancer. These miRNAs could therefore serve as diagnostic biomarkers of gastric cancer.

• Molecules and Cells
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• 제43권1호
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• pp.23-33
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• 2020

NF-κB signaling through both canonical and non-canonical pathways plays a central role in immune responses and inflammation. NF-κB-inducing kinase (NIK) stabilization is a key step in activation of the non-canonical pathway and its dysregulation implicated in various hematologic malignancies. The tumor suppressor, p53, is an established cellular gatekeeper of proliferation. Abnormalities of the TP53 gene have been detected in more than half of all human cancers. While the non-canonical NF-κB and p53 pathways have been explored for several decades, no studies to date have documented potential cross-talk between these two cancer-related mechanisms. Here, we demonstrate that p53 negatively regulates NIK in an miRNA-dependent manner. Overexpression of p53 decreased the levels of NIK, leading to inhibition of the non-canonical NF-κB pathway. Conversely, its knockdown led to increased levels of NIK, IKKα phosphorylation, and p100 processing. Additionally, miR-34b induced by nutlin-3 directly targeted the coding sequences (CDS) of NIK. Treatment with anti-miR-34b-5p augmented NIK levels and subsequent non-canonical NF-κB signaling. Our collective findings support a novel cross-talk mechanism between non-canonical NF-κB and p53.

• 생명과학회지
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• 제26권6호
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• pp.705-710
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• 2016

대장암은 세계적으로 3번째로 흔한 암종이며, 암으로 인한 사망의 주요 원인이 되고 있다. 비록 다양한 진단방법이나 치료 방법이 이용되고는 있으나 병의 진행에 관여하는 분자메커니즘 이해의 부족 때문에 여전히 완전한 치료는 어려운 실정이다. 마이크로알엔에이는 단백질 정보를 코딩하고 있지 않은 작은 알엔에이 단편이다. 이러한 마이크로알엔에이는 특정 유전자의 전사과정 또는 번역과정을 조절하는 강력한 유전자 조절자로서의 기능을 가진다. 암의 발생과정에서 중요한 세포신호 전달 과정의 손상이 빈번하게 발생 하는데, 다양한 마이크로알엔에이의 이상발현이 그 원인이 되고 있다. 마이크로알엔에이-31은 암유전자의 역할을 하며 발암과정에 관여하는 다양한 유전자를 조절한다고 알려져 있다. 따라서, 본 연구에서는 대장암에서 마이크로알엔에이-31 발현의 임상적의의를 규명하고자 하였다. 175례의 대장암 조직과 16례의 정상 대장조직에서 실시간 유전자 증폭장치를 이용하여 마이크로알엔에이-31의 발현을 분석하고, 임상병리적 요인들과의 상관관계를 분석하고 임상적 유용성을 연구해 보았다. 마이크로알엔에이-31은 정상조직에 비해 대장암 조직에서 과발현이 되어 있었다. 175례 대장암 조직을 이용한 분석에서 마이크로알엔에이-31의 발현은 병기의 진행 정도에 따라 발현이 증가 되고 있었으며, 실제 마이크로알엔에이-31의 발현이 높은 대장암 환자군의 생존률이 그렇지 않은 환자군에 비해 통계적으로 유의하게 나쁜 것으로 확인 되었다. Cox 비례위험 모형과 로지스틱 회귀 모형을 이용한 분석에서 마이크로알엔에이-31의 과발현이 직접적으로 대장암 환자의 예후 및 원발전이와 연관성이 있는 것이 확인 되었다. 따라서, 이상의 연구결과를 종합해볼 때 대장암에서 과발현 된 마이크로알엔에이-31은 대장암 환자의 예후예측 및 전이예측 바이오마커로서의 활용 가능성이 높다고 볼 수 있다.

• 생명과학회지
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• 제33권9호
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• pp.736-745
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• 2023

노화란 세포 및 생리 기능이 점진적으로 손상되는 복잡한 과정이다. 알츠하이머, 동맥경화 및 갱년기와 같은 노화와 관련된 질병은 노화가 진행이 되면서 발생된다. 노화와 관련된 질환은 다양한 원인에 의해 발생된다. 그 중 유전적인 변화 없이 유전자 발현을 조절하는 후성유전의 변화는 노화, 그리고 노화와 관련된 질환의 발생에 중요한 조절자로 알려져있다. 이 리뷰에서는 후성유전의 변화가 노화 및 노화와 관련된 질병의 발전과 진행에 어떠한 역할을 하는지에 대해 서술하였다. 노화 중에 일어나는 유전적 변화의 분자적 기전과 이러한 변화가 노화와 관련된 질병에 미치는 영향, 특히 노화와 관련된 질환과 관련된 유전자 발현 양식을 조절하는 RNA 메틸화, DNA 메틸화 및 miRNA에 대해 중점적으로 초점을 맞추었다.

• The Korean Journal of Physiology and Pharmacology
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• 제26권6호
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• pp.519-530
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• 2022

Recent research indicates that lactate promotes the switching of vascular smooth muscle cells (VSMCs) to a synthetic phenotype, which has been implicated in various vascular diseases. This study aimed to investigate the effects of lactate on the VSMC phenotype switch and the underlying mechanism. The CCK-8 method was used to assess cell viability. The microRNAs and mRNAs levels were evaluated using quantitative PCR. Targets of microRNA were predicted using online tools and confirmed using a luciferase reporter assay. We found that lactate promoted the switch of VSMCs to a synthetic phenotype, as evidenced by an increase in VSMC proliferation, mitochondrial activity, migration, and synthesis but a decrease in VSMC apoptosis. Lactate inhibited miR-23b expression in VSMCs, and miR-23b inhibited VSMC's switch to the synthetic phenotype. Lactate modulated the VSMC phenotype through downregulation of miR-23b expression, suggesting that overexpression of miR-23b using a miR-23b mimic attenuated the effects of lactate on VSMC phenotype modulation. Moreover, we discovered that SMAD family member 3 (SMAD3) was the target of miR-23b in regulating VSMC phenotype. Further findings suggested that lactate promotes VSMC switch to synthetic phenotype by targeting SMAD3 and downregulating miR-23b. These findings suggest that correcting the dysregulation of miR-23b/SMAD3 or lactate metabolism is a potential treatment for vascular diseases.

• The Korean Journal of Physiology and Pharmacology
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• 제23권3호
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• pp.171-179
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• 2019

Pituitary tumors are usually benign but can occasionally exhibit hormonal and proliferative behaviors. Dysregulation of the G1/S restriction point largely contributes to the over-proliferation of pituitary tumor cells. F-box protein S-phase kinase-interacting protein-2 (SKP2) reportedly targets and inhibits the expression of $p27^{Kip1}$, a well-known negative regulator of G1 cell cycle progression. In this study, SKP2 expression was found to be upregulated while $p27^{Kip1}$ expression was determined to be downregulated in rat and human pituitary tumor cells. Furthermore, SKP2 knockdown induced upregulation of $p27^{Kip1}$ and cell growth inhibition in rat and human pituitary tumor cells, while SKP2overexpression elicited opposite effects on $p27^{Kip1}$ expression and cell growth. The expression of microRNA-186 (miR-186) was reported to be reduced in pituitary tumors. Online tools predicted SKP2 to be a direct downstream target of miR-186, which was further confirmed by luciferase reporter gene assays. Moreover, miR-186 could modulate the cell proliferation and $p27^{Kip1}$-mediated cell cycle alternation of rat and human pituitary tumor cells through SKP2. As further confirmation of these findings, miR-186 and $p27^{Kip1}$ expression were downregulated, while SKP2 expression was upregulated in human pituitary tumor tissue samples; thus, SKP2 expression negatively correlated with miR-186 and $p27^{Kip1}$ expression. In contrast, miR-186 expression positively associated with $p27^{Kip1}$ expression. Taken together, we discovered a novel mechanism by which miR-186/SKP2 axis modulates pituitary tumor cell proliferation through $p27^{Kip1}$-mediated cell cycle alternation.