• Journal of Chest Surgery
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• 제36권12호
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• pp.952-960
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• 2003

p53은 cyclin Bl을 통해 세포주기 중 G2-M checkpoint 이행을 조절하는 것으로 알려져 있으며 이것은 p53이 여러 종류의 악성종양의 생성과 진행에 중요한 역할을 하는 것을 암시한다. 본 연구의 목적은 식도 편평세포암 환자에서 세포주기 조절인자인 cyclin Bl과 p53의 역할을 규명하는 데 있다. 대상 및 방법: 46예의 식도 편평세포암 환자에서 채취한 정상 편평상피, 이형성 조직과 암조직에서 면역조직화학검사를 이용하여 cyclin Bl과 p53의 발현을 조사하고 임상병리학적인 인자 및 생존율과의 상관관계를 분석하였다. 결과: 정상상피의 기저층에 있는 몇 개의 세포들에서 cyclin Bl이 발현되었다. Cyclin Bl 양성세포의 범위는 이형성증의 정도가 심해질수록 증가하였다. Cyclin Bl의 양성율은 41.3% (19예/46예)였고 p53의 양성 발현율은 58.7% (27예/46예)였다. 임상병리학적 인자들 중 병기(p<0.05), 식도 주위 림프절 전이(p=0.05), 림프혈관 침범(p<0.05)만이 cyclin Bl의 발현과 관련이 있었고 단변량분석과 다변량분석에서 cyclin Bl의 발현은 예후불량과 관련이 있었다. p53의 발현은 cyclin Bl의 발현과는 상관관계가 있었으나, 임상병리학적 인자들과 예후와는 무관하였다. 결론: 이상의 결과로 cyclin Bl은 식도암의 생성에 관여함을 알 수 있었고 식도 편평세포암 환자에서 cyclin Bl의 발현은 불량한 예후를 나타내며 술 후 보강 항암요법을 시행함으로써 생존율의 향상에 기여할 수 있을 것으로 생각된다.

• 한국자원식물학회지
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• 제28권6호
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• pp.682-689
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• 2015

Abeliophyllum distichum Nakai (A. distichum) has been reported to exert the inhibitory effect on angiotensin converting enzyme and aldose reductase. Recently, our group found that branch extracts of A. distichum (EAFAD-B) induce apoptosis through ATF3 activation in human colon cancer cells. However, anti-cancer reagents exert their activity through the regulation of various molecular targets. Therefore, the elucidation of potential mechanisms of EAFAD-B for anti-cancer activity may be necessary. To elucidate the potential mechanism of EAFAD-B for anti-cancer activity, we evaluated the regulation of cyclin D1 in human colon cancer cells. EAFAD-B decreased cellular accumulation of cyclin D1 protein. However, cyclin D1 mRNA was not changed by EAFAD-B. Inhibition of proteasomal degradation by MG132 attenuated EAFAD-B-mediated cyclin D1 downregulation and the half-life of cyclin D1 was decreased in the cells treated with EAFAD-B. In addition, EAFAD-B induced cyclin D1 phosphorylation at threonine-286 and the point mutation of threonine-286 to alanine attenuated EAFAD-B-mediated cyclin D1 proteasomal degradation. Inhibitions of both ERK1/2 by PD98059 and NF-κB by a selective inhibitor, BAY 11-7082 suppressed cyclin D1 downregulation by EAFAD-B. From these results, we suggest that EAFAD-B-mediated cyclin D1 downregulation may result from proteasomal degradation through its threonine-286 phosphorylation via ERK1/2-dependent NF-κB activation. The current study provides new mechanistic link between EAFAD-B and anti-cancer activity in human colon cancer cells.

• BMB Reports
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• 제46권6호
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• pp.289-294
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• 2013

To maintain cellular homeostasis against the demands of the extracellular environment, a precise regulation of kinases and phosphatases is essential. In cell cycle regulation mechanisms, activation of the cyclin-dependent kinase (CDK1) and cyclin B complex (CDK1:cyclin B) causes a remarkable change in protein phosphorylation. Activation of CDK1:cyclin B is regulated by two auto-amplification loops-CDK1:cyclin B activates Cdc25, its own activating phosphatase, and inhibits Wee1, its own inhibiting kinase. Recent biological evidence has revealed that the inhibition of its counteracting phosphatase activity also occurs, and it is parallel to CDK1:cyclin B activation during mitosis. Phosphatase regulation of mitotic kinases and their substrates is essential to ensure that the progression of the cell cycle is ordered. Outlining how the mutual control of kinases and phosphatases governs the localization and timing of cell division will give us a new understanding about cell cycle regulation.

• BMB Reports
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• 제44권8호
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• pp.553-557
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• 2011

We previously reported that CDK2/Cyclin A can phosphorylate and activate the transcription factor NF-Y. In this study, we investigated a potential regulatory role for NF-Y in the transcription of Cyclin A and other cell cycle regulatory genes. Gel-shift assays demonstrate that NF-Y binds to CCAAT sequences in the Cyclin A promoter, as well as to those in the promoters of cell cycle G2 regulators such as CDC2, Cyclin B and CDC25C. Furthermore, expression of Cyclin A increases NF-Y's affinity for CCAAT sequences in the CDC2 promoter; however, Cyclin A's induction of CDC2 transcription is antagonized by p21, an inhibitor of CDK2/Cyclin A. These results suggest a model wherein NF-Y binds to and activates transcription from the Cyclin A promoter, increasing cellular levels of Cyclin A/CDK2 and potentiating NF-Y's capacity for transcriptional transactivation, and imply a positive feedback loop between NF-Y and Cyclin A/CDK2. Our findings are additionally indicative of a role for Cyclin A in activating Cyclin B/CDK1 through promoting NF-Y dependent transcription of Cyclin B and CDC2; NF-Y mediated crosstalk may therefore help to orchestrate cell-cycle progression.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.116-116
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• 2002

Further development of reconstructed embryos may be dependent upon the synchronization of donor nucleus and recipient cytoplasm at cell fusion, To control the synchronization of donor and recipient cells, the enucleated MII arrested oocytes are artificially stimulated prior to embryo reconstruction. Destruction of cyclin B results in the exit of cells from M-phase of cell cycle. This study was designed to investigate the effects of single or combined stimulation affected cyclin B1 mRNA and protein levels in mouse oocytes. The oocyte activation was induced by 7% ethanol or 10$\mu\textrm{g}$/$m\ell$ Ca-ionophore without (single) or with (combined) 10$\mu\textrm{g}$/$m\ell$ cycloheximide. Competitive quantitative PCR for cyclin Bl mRNA and western blot analysis for cyclin B1 protein was preformed in mouse oocytes. Cyclin B1 mRNA level was significantly reduced in single (P<0.05) and combined (P<0.05) stimulation groups. However, this level did not change in non-activated group and increased in intact group. Cyclin B1 protein level was also significantly reduced in both single (P<0.05) and combined (P<0.05) stimulation groups. In conclusion, single and combined stimulation induces the degradation of cyclin B1 mRNA and protein after activation in enucleated mouse oocytes.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.115-115
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• 2002

To evaluate the correlations between the expression of cyclin B1 mRNA and protein after stimulation and oocyte activation and development of nuclear transferred mouse embryos, this study was performed. The oocyte activation was induced by 7% ethanol or 10$\mu\textrm{g}$/$m\ell$ Ca-ionophore without (single) or with (combined) 10$\mu\textrm{g}$/$m\ell$ cycloheximide (CH). Cyclin B1 mRNA and protein in mouse oocytes was evaluated by PCR and western blot. The activation and blastocyst development in both single (P<0.05) and combined (P<0.01) stimulation was higher than in non-activated group. The cyclin B1 mRNA and protein levels were significantly reduced in both single and combined stimulation groups (P<0.05), respectively. Cyclin B1 mRNA expression showed a negative correlation between activation and blastocyst development in both single and combined stimulation groups. And also the expression of cyclin B1 protein showed a negative correlation with between oocyte activation and blastocysts development in both single and combined stimulation groups. In conclusion, it may suggest that single and combined stimulation increases the oocyte activation and blastocyst development of nuclear transferred embryos, because it induces the degradation of cyclin B1 mRNA and protein after activation in enucleated mouse oocytes.

• Journal of Animal Science and Technology
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• 제48권3호
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• pp.353-360
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• 2006

본 연구는 쥐 난자에서 인위적 활성화 처리가 난자의 활성화, cyclin B1 단백질의 발현 및 난자의 활성화와 cyclin B1 단백질 발현간의 상관관계에 미치는 영향에 관하여 조사하고자 실시하였다. 난자의 활성화 처리는 7% ethanol(EtOH) or 10μg/ml Ca-ionophore with or without 10μg/ml cycloheximide (CH) 방법으로 단일 또는 복합처리 하였다. 난자의 활성화 비율은 단일처리(p<0.05)와 복합처리 (p<0.01)한 난자가 무처리에 비하여 유의하게 높았다. Cyclin B1 단백질의 발현이 EtOH+CH 처리한 난자를 제외한 다른 처리군에서는 무처리에 비하여 유의하게 감소하였다(p<0.05). 한편 EtOH+CH(r=0.61, p<0.05)와 Ca+CH(r=0.86, p<0.01) 처리그룹에서 cyclin B1 단백질의 발현과 난자의 활성화 간에 높은 역상관관계가 있음을 확인하였다. 하지만 단일처리 그룹에서는 두 요소간에 상관관계가 없음을 알 수 있었다. 따라서 단일(EtOH and Ca-ionophore) 또는 복합(EtOH+CH and Ca+CH) 활성화 처리가 난자의 활성화를 증가시키며, 이것은 난자의 활성화 처리에 따른 cyclin B1 단백질의 감소와 밀접한 연관이 있다고 사료된다.

• Reproductive and Developmental Biology
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• 제30권2호
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• pp.115-118
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• 2006

Cyclin B1 is known to reflect the M-phase promoting factor (MPF), a universal regulator of G2/M-phase transition, activity during the process of oocytes maturation. To investigate whether culture condition affects the maturation rate and the expression of cyclin B1 protein, bovine immature oocytes are stimulated and cultured according to the following protocols: Experiment 1: denuded oocytes (denude) only, COC only, denuded oocytes+granulosa cells (denude+GCs) and COC+GCs; Experiment 2: no-activation (control), 7% ethanol for 5 min and $10{\mu}l/ml$ ionomycin for 5 min at immediately before maturation. The maturation rates of denude and no-activation group were significantly lower in both experiments (P<0.05), respectively. Co-culture or stimulation method in bovine immature oocytes culture increases the cyclin B1 expression significantly in both experiments (P<0.05). Based on these results, culture condition affects the maturation rate and the expression of cyclin B1 protein during the first meiotic maturation in bovine immature oocytes.

• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1165-1169
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• 2013

To elucidate the role of PKG isoforms in transcriptional control of cyclin D1, we employed a series of expression vectors of PKG $1{\alpha}$ and PKG $1{\beta}$ which encode HA-tagged wild type and constitutively active (SD and ${\Delta}N$) mutants. Our present study demonstrates that both the constitutively active mutants of PKG $1{\beta}$ downregulate the transcription of cyclin D1 when transiently transfected in NIH3T3 cells, whereas PKG $1{\alpha}$ mutants show weak inhibition. We further studied the transcriptional regulators of cyclin D1, such as, c-fos, NF-${\kappa}B$, and CRE by using the luciferase reporter assay. Constitutively active mutants of PKG $1{\beta}$ showed marked transcriptional downregulation of c-fos in NIH3T3 cells, whereas PKG $1{\alpha}$ downregulated c-fos to a lesser extent. We also found that the constitutively active mutants of PKG negatively regulated the activation of NF-${\kappa}B$ and CRE, suggesting their involvement in the regulation of cyclin D1.

• Reproductive and Developmental Biology
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• 제35권4호
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• pp.499-502
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• 2011

Aurora A kinase is a mitotic serine/threonine kinase whose proposed functions include the maturation of centrosomes, G2/M transition, alignment of chromosomes at metaphase, and cytokinesis. In this study, we investigated the effect of MLN8237, an aurora A kinase inhibitor, on the postovulatory aging of oocytes based on the frequency of oocyte fragmentation, cdk1 kinase activity, and cyclin B degradation. The fragmentation of ovulated oocytes during prolonged culture was inhibited by treatment with MLN8237 in a concentration-dependent manner. The frequency of fragmented oocytes was significantly lower in oocytes treated with 2 ${\mu}M$ MLN8237 (13%) than in control oocytes (64%) after two days of culture. Most of the control (non-fragmented) oocytes (91%) were activated after two days of culture. In comparison, only 22% of the MLN8237-treated oocytes were activated; the rest of the oocytes (78%) were still in metaphase with an abnormal spindle and dispersed chromosomes. Next, cdk1 activity and the level of cyclin B were examined. The level of cyclin B and cdk1 activity in MLN8237-treated oocytes were nearly equal to those in control oocytes. Our results indicate that MLN8237 inhibited the fragmentation of ovulated oocytes during prolonged culture, although it blocked the spontaneous decrease in activity of cdk1 and degradation of cyclin B. This mechanism of inhibition is different from that in oocytes treated with nocodazole, which have high levels of cdk1 activity and cyclin B.