• Korean Journal of Plant Resources
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• v.30 no.6
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• pp.640-646
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• 2017

In this study, we elucidated anti-cancer activity and potential molecular mechanism of 70% ethanol extracts from Taxilli Ramulus (Taxillus chinensis (DC.) Danser) (TR-E70) against human colorectal cancer cells. Anti-cell proliferative effect of TR-E70 was evaluated by MTT assay. The effect of TR-E70 on the expression of cyclin D1 in the protein and mRNA level was evaluated by Western blot and RT-PCR, respectively. TR-E70 suppressed the proliferation of human colorectal cancer cell lines, HCT116 and SW480. Although TR-E70 decreased cyclin D1 expression in protein and mRNA level, decreased level of cyclin D1 protein by TR-E70 more dramatically occurred than that of cyclin D1 mRNA. Cyclin D1 downregulation by TR-E70 was attenuated in presence of MG132. In addition, TR-E70 phosphorylated threonine-286 (T286) of cyclin D1. TR-E70-mediated cyclin D1 degradation was blocked in presence of LiCl as an inhibitor $GSK3{\beta}$ but not PD98059 as an ERK1/2 inhibitor and SB203580 as a p38 inhibitor. Our results suggest that TR-E70 may downregulate cyclin D1 as one of the potential anti-cancer targets through $GSK3{\beta}$-dependent cyclin D1 degradation. From these findings, TR-E70 has potential to be a candidate for the development of chemoprevention or therapeutic agents for human colorectal cancer.

• Biomolecules & Therapeutics
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• v.23 no.4
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• pp.339-344
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• 2015

Naringenin (NAR) as one of the flavonoids observed in grapefruit has been reported to exhibit an anti-cancer activity. However, more detailed mechanism by which NAR exerts anti-cancer properties still remains unanswered. Thus, in this study, we have shown that NAR down-regulates the level of cyclin D1 in human colorectal cancer cell lines, HCT116 and SW480. NAR inhibited the cell proliferation in HCT116 and SW480 cells and decreased the level of cyclin D1 protein. Inhibition of proteasomal degradation by MG132 blocked NAR-mediated cyclin D1 downregulation and the half-life of cyclin D1 was decreased in the cells treated with NAR. In addition, NAR increased the phosphorylation of cyclin D1 at threonine-286 and a point mutation of threonine-286 to alanine blocked cyclin D1 downregulation by NAR. p38 inactivation attenuated cyclin D1 downregulation by NAR. From these results, we suggest that NAR-mediated cyclin D1 downregulation may result from proteasomal degradation through p38 activation. The current study provides new mechanistic link between NAR, cyclin D1 downregulation and cell growth in human colorectal cancer cells.

• Tuberculosis and Respiratory Diseases
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• v.45 no.4
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• pp.776-784
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• 1998

Background: The cyclin D1 gene is one of the most frequently amplified chromosomal regions(11q13) in human carcinomas. In laryngeal and head and neck carcinomas, its overexpression has been shown to be associated with advanced local invasion and presence of lymph node metastases. Cyclin D1 may therefore playa key role in cell growth regulation and tumorigenesis. Lung cancer is a worldwide problem and in many contries it is the most lethal malignancy. As relapse is frequent after resection of early stage non-small cell lung cancer, there is an urgent need to define prognostic factors. Purpose: This study was undertaken to evaluate the prognostic value of the cyclin D1, that is one the G1 cyclins which control cell cycle progression by allowing G1 to S phase transition, on the patients in radically resected non-small cell lung cancer. Method: Total 81 cases of formalin-fixed paraffin-embedded blocks from resected primary non-small cell lung cancer from January 1, 1983 to July 31, 1995 at Hanyang University Hospital were available for both clinical follow-up and immunohistochemical staining using monoclonal antibodies for cyclin D1. Results : The histologic classification of the tumor was based on WHO criteria, and the specimens included 45 squamous cell carcinomas, 25 adenocarcinomas and 11 large cell carcinomas. Cyclin D1 overexpression was noted in 26 cases of 81 cases tested (30.9%). Cyclin D1 expression was not significantly associated with cell types of the tumor, pathological staging and the size of the tumor. But cyclin D1 overexpression was significantly correlated with positive lymph node metastasis(p=0.035). The mean survival duration was $22.76{\pm}3.50$ months in cyclin D1 positive group and $45.38{\pm}5.64$ months in eyclin D1 negative group. There was a nearly significant difference in overall survival between cyclin D1 positive and negative groups(p=0.0515) in radically resected non-small cell lung cancer. Conclusion: Based on this study, cyelin D1 overexpression appears an important poor prognostic indicator in non-small cell lung cancer and may have diagnostic and prognostic importance in the treatment of resectable non-small cell lung cancer.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.474-481
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• 1996

Since the commercially available rabbit anti-cyclin D3, generated from c-terminal 16 amino acid residues which are common to human and murine cyclin D3, is highly cross-reactive with many other cellular proteins of mouse, a new rabbit polyclonal anti-cyclin D3 has been raised by using murine cyclin D3 protein expressed at a high level in Escherichia coli as the immunogen. To express murine cyclin D3 protein in E. coli, the cyclin D3 cDNA fragment encoding c-terminal 236 amino acid residues obtained by polymerase chain reaction (PCR) was inserted into the NcoI/BamHI site of protein expression vector, pET 3d. Molecular mass of the cyclin D3 overexpressed in the presence of IPTG (Isopropyl $\beta$-D-thiogalactopyranoside) was approximately 26 kDa as calculated from the reading frame on the DNA sequence, and the protein was insoluble and mainly localized in the inclusion bodies that could be easily purified from the other cellular soluble proteins. When renaturation was performed following denaturation of the insoluble cyclin D3 protein in the inclusion bodies using guanidine hydrochloride, 4.4 mg of soluble form of cyclin D3 protein was produced from the transformant cultured in 100ml of LB media under the optimum conditions. Four-hundred micrograms of the soluble form of cyclin D3 protein was used for each immunization of a rabbit. When the antiserum obtained 2 weeks after tertiary immunization was applied to Western blot analysis, it was able to detect 33 kDa cyclin D3 protein in both murine lymphoma cell line BW5147.G.1.4 and human Jurkat T cells at 3,000-fold dilution with higher specificity to murine cyclin D3, demonstrating that the new rabbit polyclonal anti-murine cyclin D3 generated against c-terminal 236 amino acid residues more specifically recognizes murine cyclin D3 protein than does the commercially available rabbit polyclonal antibody raised against c-terminal 16 amino acids residues.

• Journal of Life Science
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• v.16 no.4
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• pp.598-604
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• 2006

The $Ca^{2+}-activated$ neutral protease calpain induced proteolysis has been suggested to play a role in certain cell growth regulatory proteins. Cyclin proteolysis is essential for cell cycle progression. D-type cyclins, which form an assembly with cyclin-dependent kinases (cdk4 and cdk6), are synthesized earlier in G1 of the cell cycle and seem to be induced in response to external signals that promote entry into the cell cycle. Here we show that cyclin D3 protein levels are regulated at the posttranscriptional level by calpain protease. Treatment of human breast carcinoma MDA-MB-231 cells with lovastatin and actinomycin D resulted in a loss of cyclin D3 protein that was completely reversible by the peptide aldehyde calpain inhibitor, LLnL. The specific inhibitor of the 26S proteasome, lactacystin, the lysosome inhibitors, ammonium chloride and chloroquine, and the serine protease inhibitor, phenylmethylsulfonylfluoride (PMSF), did not block the degradation of cyclin D3 by lovastatin and actinomycin D. Results of in vitro degradation of cyclin D3 by purified calpain showed that cyclin D3 protein is degraded in a $Ca^{2+}-dependent$ manner, and the half-life of cyclin D3 protein was dramatically increased in LLnL treated cells. These data suggested that cyclin D3 protein is regulated by the $Ca^{2+}-activated$ protease calpain.

• Korean Journal of Plant Resources
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• v.33 no.4
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• pp.271-278
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• 2020

In this study, we evaluated the anti-cancer activity and potential molecular mechanism of 70% ethanol extracts of the Berchemia floribunda (BF) which belongs to Rhamnaceae against human colorectal cancer cells. The treatment of BF decreased the cell proliferation in HCT116 cell and suppressed cellular accumulation of Cyclin D1 protein. Inhibition of proteasomal activity by MG132 attenuated BF-mediated Cyclin D1 downregulation and Cyclin D1 was decreased in the cell treated with BF. These findings indicates that BF-mediated Cyclin D1 downregulation may be result from Cyclin D1 proteasomal degradation. Additionally, BF-mediated Cyclin D1 degradation was blocked in the presence of LiCl, a GSK3β inhibitor, but not PD98059, SP600125, SB203580, Bay11-7082, LY294002 an ERK1/2 inhibitor, JNK inhibitor, p38 inhibitor, IκK inhibitor and PI3K inhibitor. Furthermore, BF phosphorylated Cyclin D1 at threonine-286 (Thr286), and LiCl-induced GSK3β inhibition reduced the BF mediated phosphorylation of Cyclin D1 at Thr286. These results suggested that BF may downregulate Cyclin D1 expression as a potential anti-cancer target through GSK3β dependent Cyclin D1 degradation. Therefore, this study provides that the extract of BF has anticancer activity against human colorectal cancer cells.

• Korean Journal of Medicinal Crop Science
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• v.25 no.5
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• pp.328-334
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• 2017

Background: In this study, we evaluated the anti-cancer activity and potential molecular mechanism of 70% ethanol extracts of the root of Aralia cordata var. continentalis (Kitagawa) Y. C. Chu (RAc-E70) against human colorectal cancer cells. Methods and Results: RAc-E70 suppressed the proliferation of the human colorectal cancer cell lines, HCT116 and SW480. Although RAc-E70 reduction cyclin D1 expression at the protein and mRNA levels, RAc-E70-induced reduction in cyclin D1 protein level occurred more dramatically than that of cyclin D1 mRNA. The RAc-E70-induced downregulation of cyclin D1 expression was attenuated in the presence of MG132. Additionally, RAc-E70 reduced HA-cyclin D1 levels in HCT116 cells transfected with HA-tagged wild type-cyclin D1 expression vector. RAc-E70-mediated cyclin D1 degradation was blocked in the presence of LiCl, a $GSK3{\beta}$ inhibitorbut, but not PD98059, an ERK1/2 inhibitor and SB203580, a p38 inhibitor. Furthermore, RAc-E70 phosphorylated cyclin D1 at threonine-286 (T286), and LiCl-induced $GSK3{\beta}$ inhibition reduced the RAc-E70-mediated phosphorylation of cyclin D1 at T286. Conclusions: Our results suggested that RAc-E70 may downregulate cyclin D1 expression as a potential anti-cancer target through $GSK3{\beta}$-dependent cyclin D1 degradation. Based on these findings, RAc-E70 maybe a potential candidate for the development of chemopreventive or therapeutic agents for human colorectal cancer.

• Korean Journal of Plant Resources
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• v.31 no.3
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• pp.218-227
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• 2018

In this study, we investigated the effect of the extracts from Vaccinium oldhamii on cell proliferation and the regulatory mechanisms of cyclin D1 protein level in human cancer cells. The branch extracts from Vaccinium oldhamii (VOB) showed higher inhibitor effect against the cell growth than leave extracts (VOL) and fruit extracts (VOF) in human colorectal cancer, breast cancer, prostate cancer, non-small lung cancer, pancreatic cancer and liver cancer cells. In addition, VOB decreased cyclin D1 level at both protein and mRNA level. MG132 treatment attenuated VOB-mediated cyclin D1 downregulation. A point mutation of threonine-286 to alanine attenuated cyclin D1 degradation by VOB. In addition, the inhibition of nuclear export by leptomycin B (LMB) attenuated cyclin D1 degradation by VOB. But, the treatment of PD98059 (ERK1/2 inhibitor), SB203580 (p38 inhibitor), SP600125 (JNK inhibitor), LiCl ($GSK3{\beta}$ inhibitor), LY294002 (PI3K inhibitor) or BAY 11-7082 ($I{\kappa}K$ inhibitor) did not affect VOB-induced cyclin D1 degradation. In conclusion, VOB induced cyclin D1 degradation through redistribution of cyclin D1 from the nucleus to cytoplasm via T286 phosphorylation of cyclin D1, which resulted in the inhibition of cancer cell proliferation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.5
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• pp.324-330
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• 2017

Objectives: There are only a limited number of studies on cyclin D1 and p63 expression in oral squamous cell carcinoma (OSCC) and leukoplakia. This study compared cyclin D1 and p63 expression in leukoplakia and OSCC to investigate the possible correlation of both markers with grade of dysplasia and histological grade of OSCC. Materials and Methods: The study included a total of 60 cases, of which 30 were diagnosed with OSCC and 30 with leukoplakia, that were evaluated immunohistochemically for p63 and cyclin D1 expression. Protein expression was correlated based on grades of dysplasia and OSCC. Results: Out of 30 cases of OSCC, 23 cases (76.7%) were cyclin D1 positive and 30 cases (100%) were p63 positive. Out of 30 cases of leukoplakia, 21 cases (70.0%) were cyclin D1 positive and 30 (100%) were p63 positive (P<0.05). Conclusion: The overall expression of cyclin D1 and p63 correlated with tumor differentiation, and increases were correlated with poor histological grades, from well-differentiated to poorly-differentiated SCC. Increased cyclin D1 and p63 expression was associated with the severity of leukoplakia. Based on these results cyclin D1 and p63 products can be a useful tool for improved leukoplakia prognosis.

• 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.