• Journal of Life Science
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• v.29 no.6
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• pp.679-687
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• 2019

Litsea populifolia, a plant species of the Lauraceae family, is widely distributed in the tropical and subtropical areas of Asia. The phylogenetic relationships and botanical characteristics of L. populifolia have been reported; however, its anti-oxidative and anti-cancer activities remain unclear. In this study, we evaluated the anti-oxidative and anti-cancer effects of ethanol extracts of L. populifolia (EELP) together with the molecular mechanism of its anti-cancer activity in human lung adenocarcinoma A549 cells. EELP showed significant anti-oxidative effects with a 50% inhibitory concentration at $11.71{\mu}g/ml$, which was measured by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. EELP exhibited cytotoxic activity and induced cell cycle arrest at the G1 phase in A549 cells in a dose-dependent manner, whereas EELP did not have the cytotoxic effect on the normal human lung cell line IMR90. Treatment with EELP also resulted in a decreased expression of G1/S transition-related molecules-including cyclin-dependent kinase (CDK) 2, CDK6, cyclin D1, and cyclin E-both for the transcription and translation levels. EELP-induced G1 arrest was associated with the phosphorylation of checkpoint kinase 2 (CHK2), p53, cell division cycle 25 homolog A (CDC25A), and the reduction of CDC25A expression in A549 cells. Collectively, these results suggest that EELP may exert an anti-cancer effect by cell cycle arrest at the G1 phase through both p53-dependent and p53-independent (ATM/CHK2/CDC25A/CDK2) pathways in A549 cells.

• BMB Reports
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• v.31 no.1
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• pp.48-52
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• 1998

$p16^{INK4}$, which is a 16-kDa polypeptide protein, inhibits the catalytic activity of the CDK4-cyclinD complex to suppress rumor growth. Both unlabeled and isotope-labeled human tumor suppressor $p16^{INK4}$ protein were overexpressed and purified to characterize biochemical and structural properties. The purified p16 binds to monomeric GST-CDK4 and exists in a monomer conformation for several weeks at $4^{\circ}C$. The circular dichroism (CD) data indicates that p16 contains high percentage of ${\alpha}$-helix and that the helix percentage maximized at pH value of 7.0. One-and two-dimensional nuclear magnetic resonance (NMR) data suggest that purified p16 from our construct has a unique folded conformation under our experimental conditions and exhibits quite stable conformational characteristics.

• Plant Biotechnology Reports
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• v.2 no.4
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• pp.227-231
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• 2008

D-class cyclins play important roles in controlling the cell cycle in development and in response to external signals by forming the regulatory subunit of cyclin-dependent kinase (CDK) complexes. To evaluate the effects of D-class cyclins in transgenic rice plants, Arabidopsis cyclin D2 gene (CycD2) was linked to the maize ubiquitin1 promoter (Ubi1) and introduced into rice by the Agrobacterium-mediated transformation method. Genomic deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and Western blot hybridizations of the Ubi1:-CycD2 plants revealed copy number of transgene and its increased expression in leaf and callus cells at messenger RNA (mRNA) and/or protein levels. The H1 kinase assay using the immunoprecipitates of protein extracts from the Ubi1:CycD2 plants and nontransgenic controls demonstrated that the introduced Arabidopsis CycD2 forms a functional CycD2/CDK complex with an unidentified CDK of rice. Shoot and root growth was enhanced in the Ubi1:CycD2 seedlings compared with nontransgenic controls, together, suggesting that Arabidopsis cyclin D2 interacts with a rice cyclin-dependent kinase, consequently enhancing seedling growth.

• Molecules and Cells
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• v.39 no.9
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• pp.699-704
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• 2016

Developmentally regulated GTP-binding protein 2 (DRG2) plays an important role in cell growth. Here we explored the linkage between DRG2 and G2/M phase checkpoint function in cell cycle progression. We observed that knockdown of DRG2 in HeLa cells affected growth in a wound-healing assay, and tumorigenicity in nude mice xenografts. Flow cytometry assays and [$^3H$] incorporation assays indicated that G2/M phase arrest was responsible for the decreased proliferation of these cells. Knockdown of DRG2 elicited down-regulation of the major mitotic promoting factor, the cyclin B1/Cdk1 complex, but upregulation of the cell cycle arresting proteins, Wee1, Myt1, and p21. These findings identify a novel role of DRG2 in G2/M progression.

• International Journal of Oral Biology
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• v.41 no.3
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• pp.113-118
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• 2016

An FDA approved drug for the treatment of type II diabetes, Troglitazone (TRO), a peroxisome proliferator-activated receptor gamma agonist, is withdrawn due to severe idiosyncratic hepatotoxicity. In the search for new applications of TRO, we investigated the cellular effects of TRO on YD15 tongue carcinoma cells. TRO suppressed the growth of YD15 cells in the MTT assay. The inhibition of cell growth was accompanied by the induction of cell cycle arrest at $G_0/G_1$ and apoptosis, which are confirmed by flow cytometry and western blotting. TRO also suppressed the expression of cell cycle proteins such as cyclin D1, cdk2, cdk4, cyclin B1, cdk1(or cdc2), cyclin E1 and cyclin A. The inhibition of cell cycle proteins was coincident with the up-regulation of $p21^{CIP1/WAF1}$ and $p27^{KIP1}$. In addition, TRO induces the activation of caspase-3 and caspase-7, as well as the cleavage of PARP. Further, TRO suppressed the expressions of Bcl-2 without affecting the expressions of Bad and Bax. Overall, our data supports that TRO induces cell cycle arrest and apoptosis on YD15 cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1423-1430
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• 2009

Rosmarinic acid frequently found as a secondary metabolite in herbs and medicinal plants, has exhibited antimicrobial, antiviral, antioxidative, and anti-inflammatory activities. The proliferation and migration of human aortic smooth muscle cells (HASMC) in response to activation by various stimuli plays a critical role in the initiation and development of atherosclerosis. This study was conducted to examine the effects of Rosmarinic acid on the proliferation and migration of HASMC. Rosmarinic acid suppressed the proliferation of HASMC via induction of the expression of apoptotic proteins including cleaved poly ADP-ribose polymerase (PARP), and caspase-3. Rosmarinic acid decreased anti-apoptotic Bcl-2 and increased pro-apoptotic Bax. Moreover, treatment of rosmarinic acid decreased the G1/S cycle regulation proteins (cyclin D1, cyclin E, CDK2, CDK4 and CDK6) and increased p21, p27 and p53. Rosmarinic acid also blocked HASMC migration via suppression of MMP-9 and MMP-2. Taken together, these results indicate that rosmarinic acid has the potential for use as an anti-atherosclerosis agent.

• Molecules and Cells
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• v.42 no.7
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• pp.557-567
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• 2019

TSPAN12, a member of the tetraspanin family, has been highly connected with the pathogenesis of cancer. Its biological function, however, especially in ovarian cancer (OC), has not been well elucidated. In this study, The Cancer Genome Atlas (TCGA) dataset analysis revealed that upregulation of TSPAN12 gene expression was significantly correlated with patient survival, suggesting that TSPAN12 might be a potential prognostic marker for OC. Further exploration showed that TSPAN12 overexpression accelerated proliferation and colony formation of OVCAR3 and SKOV3 OC cells. Knockdown of TSPAN12 expression in A2780 and SKOV3 cells decreased both proliferation and colony formation. Western blot analysis showed that several cyclins and cyclin-dependent kinases (CDK) (e.g., Cyclin A2, Cyclin D1, Cyclin E2, CDK2, and CDK4) were significantly involved in the regulation of cell cycle downstream of TSPAN12. Moreover, TSPAN12 accelerated mitotic progression by controlling cell cycle. Thus, our data demonstrated that TSPAN12 could be a novel molecular target for the treatment of OC.

• Korean Journal of Clinical Pharmacy
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• v.30 no.1
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• pp.1-10
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• 2020

Objective: The aim of the study was to perform a meta-analysis of randomized clinical trials to compare the clinical efficacy and safety between combination of cyclin-dependent kinase (CDK) 4/6 inhibitors with aromatase inhibitors (AIs) and AIs alone in patients with hormone receptor+/human epidermal growth factor receptor type2-(HR+/HER2-) advanced breast cancer. Methods: Published clinical studies were identified through electronic database searches until February 2019. Literature qualities were assessed by the Scottish Intercollegiate Guidelines Network Checklist. Key endpoints of efficacy were progression-free survival (PFS), objective response rate (ORR), and clinical benefit (CB). Endpoints of safety were adverse events (AEs) (neutropenia, leukopenia, any grade 3/4 AEs, and serious AEs) and on-treatment death. Meta-analysis was performed using the RevMan 5.3 software. Results: The selected five studies were evaluated as "good" in quality assessment. Compared to AIs alone, the combination therapy significantly improved PFS (pooled hazard ratio=0.55; 95% confidence interval (CI) 0.49-0.62), ORR (odds ratio=1.78; 95% CI=1.49-2.13), and CB (odds ratio=1.86; 95% CI=1.51-2.28). The prevalence of AEs was significantly higher in the combination group than in the AIs alone group. On-treatment death was greater in the combination group than in the AIs alone group, although insignificant. Conclusion: The combination therapy of CDK4/6 inhibitors with AIs was more effective for the treatment of HR+/HER2- advanced breast cancer, but less safe than AIs alone. The combination therapy should be effectively managed through patient monitoring, and further studies are needed to reduce AEs in the combination therapy of CDK4/6 inhibitors with AIs.

• Journal of Life Science
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• v.14 no.5
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• pp.800-808
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• 2004

Resveratrol, a phytoalexin found at high levels in grapes and in grape products such as red wine, has been reported to possess a wide range of biological and pharmacological activities including antioxident, anti-inflammatory, anti-mutagenic, and anti-carcinogenic effects. According to recent studies, this compound is an effective inhibitor of cell growth in general, triggers partial arrest of the cell cycle and induce apoptosis. In this study, the anti-proliferative effects of resveratrol in A549 human lung carcinoma cells were investigated. It is shown that resveratrol induced the growth inhibition in a time-dependent manner and morphological changes of A549 cells, which were associated with induction of S phase arrest of the cell cycle and apoptotic cell death. The Bcl-$X_L$levels were markedly down-regulated in resveratrol treated cells, however, Bax and Bcl-2 were remained unchanged. Resveratrol treatment induced the proteolytic degradation of Sp-l and proliferating cell nuclear antigen protein, and inhibited the expression of $\beta$-catenin protein. Resveratrol treatment also induced a marked up-regulation of cyclin-dependent kinase (Cdk) inhibitor p21 and inhibited the kinase activities of Cdk2 and Cdk4. In addition, resveratrol treatment inhibited the levels of cyclooxygenase (COX)-2 mRNA and protein, and the release of prostagladin E2 without alteration of COX-1 expression. Taken together, these findings suggest that resveratrol may be a potential chemotherapeutic agent for the control of human lung carcinorma cells.

• KSBB Journal
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• v.30 no.4
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• pp.175-181
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• 2015

Cells proliferate via repeating process that growth and division. This process is G1, S, G2 and M four phases consists. Monitoring the progression of the cell cycle is a specific step that to be a continuous process is repeated to adjust the start of the next step. At this time, this process is called a Checkpoint. Currently, there are three known checkpoints that G1-S phase, G2-M phase, and the M phase. In this study, we confirmed that cell cycle arrest effects by ethanol extracts of Artemisia annua Linne (AAE) in Hep3B liver cancer cells. AAE was regulated proteins which involved in cell cycle such as pAkt, pMDM2, p53, p21, pCDK2 (T14/Y15). AAE induced cell cycle arrest in G1 checkpoint through phosphorylation of CDK2. Akt and p53 upstream is inhibited by AAE and p53 activated by non-activated pMDM2, p53 inhibitor. Thereby, activated p53 is transcript to p21 and activated p21 protein is combined with Cyclin E-pCDK2 complex. Therefore, we confirmed that AAE-induced cell cycle arrest was occurred by p21-Cyclin E-pCDK2 complex by inhibition of pAkt signal. Because of this cell cycle can't pass to S phase from G1 phase.