Increasing evidence suggests that Cyclin A-Cdk2 activity is required in the apoptosis process induced by various stimuli.To determine a specific substrate of Cyclin A-Cdk2 for apoptosis,in this study,we carried out an...Increasing evidence suggests that Cyclin A-Cdk2 activity is required in the apoptosis process induced by various stimuli.To determine a specific substrate of Cyclin A-Cdk2 for apoptosis,in this study,we carried out an in vitro kinase assay using immunoprecipitated complex Cyclin A-Cdk2 as an enzyme source,and recombinant protein GST-Bad as a substrate.Our study showed that Bad was clearly phosphorylated by Cyclin A-Cdk2 in vitro.To examine whether protein Bad can also be phosphorylated by Cyclin A-Cdk2 kinase in vivo,we transiently overexpressed protein Bad with Cyclin A or Cdk2-dn,a dominant negative version of Cdk2,in Hela cells and determined the phosphorylation status of protein Bad.The test showed that protein Bad was clearly phosphorylated in Cyclin A overexpressed cells,but not in Cdk2-dn or mock transfectent.Moreover,etoposide also caused the phosphorylation of endogenetic Bad.In conclusion,here we provide first time evidence that protein Bad can be a substrate of Cyclin A-Cdk2 apoptosis for in vitro and in vivo.展开更多
In order to investigate the relationship between the expression of cyclin A and drug resistance in adult patients with acute leukemia (AL), the mRNA expression of cyclin A, mdr1, TopⅡ α , bcl-2 was detected in 6...In order to investigate the relationship between the expression of cyclin A and drug resistance in adult patients with acute leukemia (AL), the mRNA expression of cyclin A, mdr1, TopⅡ α , bcl-2 was detected in 64 adult patients with AL and 20 normal controls by semi-reverse transcription polymerse chain reaction (semi-RT-PCR). It was found that the cyclin A and TopⅡ α mRNA expression levels in drug resistant group were significantly lower than in sensitive group ( P <0.01). Under the same experimental condition no cyclin A mRNA expression was detectable in all normal controls. The mdr1 and bcl-2 mRNA expression levels in resistant group were significantly higher than in sensitive group ( P <0.01). cyclin A and TopⅡ α gene expression levels were closely correlated ( r s =+0.794, P=0.000, n =64) in all AL patients, but cyclin A was not correlated with mdr1 and bcl-2 gene expression levels. In drug resistant group there was a negative correlation between the gene expression levels of cyclin A and mdr1 ( r s =-0.337, P=0.029 ). The 10 AL patients with positive lower expression of both cyclin A and TopⅡ α were all resistant to drugs. Logistic regression of Binary analysis showed the correlation between the lower expression of cyclin A and drug resistance. It was concluded that lower expression of cyclin A gene might be an unfavorable prognostic factor for patients with AL, and detection of both cyclin A and TopⅡ α gene expression would predict drug resistance in AL patients.展开更多
Objective To study the relation of the mRNA and protein expression of CyclinA and p21cip1 in different stages hypertrophic scar fibroblast (FB) with its cell cycle,so as to provide theoretical evidence for interventio...Objective To study the relation of the mRNA and protein expression of CyclinA and p21cip1 in different stages hypertrophic scar fibroblast (FB) with its cell cycle,so as to provide theoretical evidence for intervention therapy of展开更多
Cyclin A2 is an essential regulator of the cell division cycle through the activation of kinases that participate to the regulation of S phase as well as the mitotic entry. However,whereas its degradation by the prote...Cyclin A2 is an essential regulator of the cell division cycle through the activation of kinases that participate to the regulation of S phase as well as the mitotic entry. However,whereas its degradation by the proteasome in mid mitosis was thought to be essential for mitosis to proceed,recent observations show that a small fraction of cyclin A2 persists beyond metaphase and is degraded by autophagy. Its implication in the control of cytoskeletal dynamics and cell movement has unveiled its role in the modulation of Rho A activity. Since this GTPase is involved in both cell rounding early in mitosis and later,in the formation of the cleavage furrow,this suggests that cyclin A2 is a novel actor in cytokinesis. Taken together,these data point to this cyclin as a potential mediator of cell-niche interactions whose dysregulation could be taken as a hallmark of metastasis.展开更多
BACKGROUND Cell division cyclin 25C(CDC25C)is a protein that plays a critical role in the cell cycle,specifically in the transition from the G2 phase to the M phase.Recent research has shown that CDC25C could be a pot...BACKGROUND Cell division cyclin 25C(CDC25C)is a protein that plays a critical role in the cell cycle,specifically in the transition from the G2 phase to the M phase.Recent research has shown that CDC25C could be a potential therapeutic target for cancers,particularly for hepatocellular carcinoma(HCC).However,the specific regulatory mechanisms underlying the role of CDC25C in HCC tumorigenesis and development remain incompletely understood.AIM To explore the impact of CDC25C on cell proliferation and apoptosis,as well as its regulatory mechanisms in HCC development.METHODS Hepa1-6 and B16 cells were transduced with a lentiviral vector containing shRNA interference sequences(LV-CDC25C shRNA)to knock down CDC25C.Subsequently,a xenograft mouse model was established by subcutaneously injecting transduced Hepa1-6 cells into C57BL/6 mice to assess the effects of CDC25C knockdown on HCC development in vivo.Cell proliferation and migration were evaluated using a Cell Counting Kit-8 cell proliferation assays and wound healing assays,respectively.The expression of endoplasmic reticulum(ER)stress-related molecules(glucose-regulated protein 78,X-box binding protein-1,and C/EBP homologous protein)was measured in both cells and subcutaneous xenografts using quantitative real-time PCR(qRT-PCR)and western blotting.Additionally,apoptosis was investigated using flow cytometry,qRT-PCR,and western blotting.RESULTS CDC25C was stably suppressed in Hepa1-6 and B16 cells through LV-CDC25C shRNA transduction.A xenograft model with CDC25C knockdown was successfully established and that downregulation of CDC25C expression significantly inhibited HCC growth in mice.CDC25C knockdown not only inhibited cell proliferation and migration but also significantly increased the ER stress response,ultimately promoting ER stress-induced apoptosis in HCC cells.CONCLUSION The regulatory mechanism of CDC25C in HCC development may involve the activation of ER stress and the ER stress-induced apoptosis signaling pathway.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.30370294and30640064).
文摘Increasing evidence suggests that Cyclin A-Cdk2 activity is required in the apoptosis process induced by various stimuli.To determine a specific substrate of Cyclin A-Cdk2 for apoptosis,in this study,we carried out an in vitro kinase assay using immunoprecipitated complex Cyclin A-Cdk2 as an enzyme source,and recombinant protein GST-Bad as a substrate.Our study showed that Bad was clearly phosphorylated by Cyclin A-Cdk2 in vitro.To examine whether protein Bad can also be phosphorylated by Cyclin A-Cdk2 kinase in vivo,we transiently overexpressed protein Bad with Cyclin A or Cdk2-dn,a dominant negative version of Cdk2,in Hela cells and determined the phosphorylation status of protein Bad.The test showed that protein Bad was clearly phosphorylated in Cyclin A overexpressed cells,but not in Cdk2-dn or mock transfectent.Moreover,etoposide also caused the phosphorylation of endogenetic Bad.In conclusion,here we provide first time evidence that protein Bad can be a substrate of Cyclin A-Cdk2 apoptosis for in vitro and in vivo.
文摘In order to investigate the relationship between the expression of cyclin A and drug resistance in adult patients with acute leukemia (AL), the mRNA expression of cyclin A, mdr1, TopⅡ α , bcl-2 was detected in 64 adult patients with AL and 20 normal controls by semi-reverse transcription polymerse chain reaction (semi-RT-PCR). It was found that the cyclin A and TopⅡ α mRNA expression levels in drug resistant group were significantly lower than in sensitive group ( P <0.01). Under the same experimental condition no cyclin A mRNA expression was detectable in all normal controls. The mdr1 and bcl-2 mRNA expression levels in resistant group were significantly higher than in sensitive group ( P <0.01). cyclin A and TopⅡ α gene expression levels were closely correlated ( r s =+0.794, P=0.000, n =64) in all AL patients, but cyclin A was not correlated with mdr1 and bcl-2 gene expression levels. In drug resistant group there was a negative correlation between the gene expression levels of cyclin A and mdr1 ( r s =-0.337, P=0.029 ). The 10 AL patients with positive lower expression of both cyclin A and TopⅡ α were all resistant to drugs. Logistic regression of Binary analysis showed the correlation between the lower expression of cyclin A and drug resistance. It was concluded that lower expression of cyclin A gene might be an unfavorable prognostic factor for patients with AL, and detection of both cyclin A and TopⅡ α gene expression would predict drug resistance in AL patients.
文摘Objective To study the relation of the mRNA and protein expression of CyclinA and p21cip1 in different stages hypertrophic scar fibroblast (FB) with its cell cycle,so as to provide theoretical evidence for intervention therapy of
基金Supported by Agence Nationale de la Recherche(08-BLAN-0037-02),Fondation ARC pour la Recherche sur le Cancerand Gefluc+2 种基金CNRS/Région Languedoc-Roussillon and Fondation pour la Recherche Médicale(Loukil A)the French Ministry of Education and Research and Fondation pour la Recherche Médicale(Bendris N)the Canadian Institutes of Health Research,La Ligue Contre le Cancer and the Fondation de France(Cheung CT)
文摘Cyclin A2 is an essential regulator of the cell division cycle through the activation of kinases that participate to the regulation of S phase as well as the mitotic entry. However,whereas its degradation by the proteasome in mid mitosis was thought to be essential for mitosis to proceed,recent observations show that a small fraction of cyclin A2 persists beyond metaphase and is degraded by autophagy. Its implication in the control of cytoskeletal dynamics and cell movement has unveiled its role in the modulation of Rho A activity. Since this GTPase is involved in both cell rounding early in mitosis and later,in the formation of the cleavage furrow,this suggests that cyclin A2 is a novel actor in cytokinesis. Taken together,these data point to this cyclin as a potential mediator of cell-niche interactions whose dysregulation could be taken as a hallmark of metastasis.
基金Supported by Natural Science Foundation of Guangxi Zhuang Autonomous Region,China,No.2023GXNSFAA026070 and No.2018GXNSFAA281071.
文摘BACKGROUND Cell division cyclin 25C(CDC25C)is a protein that plays a critical role in the cell cycle,specifically in the transition from the G2 phase to the M phase.Recent research has shown that CDC25C could be a potential therapeutic target for cancers,particularly for hepatocellular carcinoma(HCC).However,the specific regulatory mechanisms underlying the role of CDC25C in HCC tumorigenesis and development remain incompletely understood.AIM To explore the impact of CDC25C on cell proliferation and apoptosis,as well as its regulatory mechanisms in HCC development.METHODS Hepa1-6 and B16 cells were transduced with a lentiviral vector containing shRNA interference sequences(LV-CDC25C shRNA)to knock down CDC25C.Subsequently,a xenograft mouse model was established by subcutaneously injecting transduced Hepa1-6 cells into C57BL/6 mice to assess the effects of CDC25C knockdown on HCC development in vivo.Cell proliferation and migration were evaluated using a Cell Counting Kit-8 cell proliferation assays and wound healing assays,respectively.The expression of endoplasmic reticulum(ER)stress-related molecules(glucose-regulated protein 78,X-box binding protein-1,and C/EBP homologous protein)was measured in both cells and subcutaneous xenografts using quantitative real-time PCR(qRT-PCR)and western blotting.Additionally,apoptosis was investigated using flow cytometry,qRT-PCR,and western blotting.RESULTS CDC25C was stably suppressed in Hepa1-6 and B16 cells through LV-CDC25C shRNA transduction.A xenograft model with CDC25C knockdown was successfully established and that downregulation of CDC25C expression significantly inhibited HCC growth in mice.CDC25C knockdown not only inhibited cell proliferation and migration but also significantly increased the ER stress response,ultimately promoting ER stress-induced apoptosis in HCC cells.CONCLUSION The regulatory mechanism of CDC25C in HCC development may involve the activation of ER stress and the ER stress-induced apoptosis signaling pathway.
