目的探讨乙酰化STAT3对DIRAS2基因表达的调控及其在三阴性乳腺癌(triple-negative breast cancer,TNBC)细胞增殖中的作用。方法通过数据库查询、Western blotting和qRT-PCR分析TNBC组织和细胞中DIRAS2和乙酰化STAT3的表达水平。选取TNB...目的探讨乙酰化STAT3对DIRAS2基因表达的调控及其在三阴性乳腺癌(triple-negative breast cancer,TNBC)细胞增殖中的作用。方法通过数据库查询、Western blotting和qRT-PCR分析TNBC组织和细胞中DIRAS2和乙酰化STAT3的表达水平。选取TNBC细胞系MDA-MB-231和SUM159,通过慢病毒或质粒构建DIRAS2过表达及STAT3野生或Lys685位点突变的细胞株。利用CCK-8实验评估DIRAS2和STAT3乙酰化对TNBC细胞增殖的影响。应用Western blotting、焦磷酸测序、ChIP和IP技术研究乙酰化STAT3对DIRAS2表达的调控作用及机制。结果DIRAS2在TNBC组织和细胞中表达较低。焦磷酸测序分析发现,与正常乳腺上皮细胞相比,TNBC细胞中DIRAS2启动子区域的CpG岛甲基化水平升高,并促进癌细胞增殖。此外,TNBC细胞中STAT3的乙酰化程度增加,而DIRAS2启动子甲基化状态随着STAT3乙酰化的增加而发生改变。ChIP和IP实验表明,乙酰化STAT3可与DIRAS2启动子结合,而STAT3 Lys685位点突变会破坏STAT3与DNMT1的相互作用。结论在TNBC中,乙酰化STAT3通过招募DNMT1诱导DIRAS2基因启动子甲基化,从而导致DIRAS2表达缺失和癌细胞增殖。展开更多
Background:p53 and DIRAS3 are tumor suppressors that are frequently silenced in tumors.In this study,we sought to determine whether the concurrent re-expression of p53 and DIRAS3 could effectively induce head and neck...Background:p53 and DIRAS3 are tumor suppressors that are frequently silenced in tumors.In this study,we sought to determine whether the concurrent re-expression of p53 and DIRAS3 could effectively induce head and neck squamous cell carcinoma(HNSCC)cell death.Methods:CAL-27 and SCC-25 cells were treated with Ad-DIRAS3 and rAd-p53 to induce re-expression of DIRAS3 and p53 respectively.The effects of DIRAS3 and p53 re-expression on the growth and apoptosis of HNSCC cells were examined by TUNEL assay,flow cytometric analysis and MTT.The effects of DIRAS3 and p53 re-expression on Akt phosphorylation,oncogene expression,and the interaction of 4 E-BP1 with eIF4 E were determined by real-time PCR,Western blotting and immunoprecipitation analysis.The ability of DIRAS3 and p53 re-expression to induce autophagy was evaluated by transmission electron microscopy,LC3 fluorescence microscopy and Western blotting.The effects of DIRAS3 and p53 re-expression on HNSCC growth were evaluated by using an orthotopic xenograft mouse model.Results:TUNEL assay and flow cytometric analysis showed that the concurrent re-expression of DIRAS3 and p53 significantly induced apoptosis(P<0.001).MTT and flow cytometric analysis revealed that DIRAS3 and p53 reexpression significantly inhibited proliferation and induced cell cycle arrest(P<0.001).Mechanistically,the concurrent re-expression of DIRAS3 and p53 down-regulated signal transducer and activation of transcription 3(STAT3)and upregulated p21WAF1/CIP1 and Bax(P<0.001).DIRAS3 and p53 re-expression also inhibited Akt phosphorylation,increased the interaction of eIF4 E with 4 E-BP1,and reduced the expression of c-Myc,cyclin D1,vascular endothelial growth factor(VEGF),fibroblast growth factor(FGF),epidermal growth factor receptor(EGFR)and Bcl-2(P<0.001).Moreover,the concurrent re-expression of DIRAS3 and p53 increased the percentage of cells with GFP-LC3 puncta compared with that in cells treated with control adenovirus(50.00%±4.55%vs.4.67%±1.25%,P<0.001).LC3 fluorescence microscopy and Western blotting further showed that DIRAS3 and p53 re-expression significantly promoted autophagic activity but also inhibited autophagic flux,resulting in overall impaired autophagy.Finally,the concurrent re-expression of DIRAS3 and p53 significantly decreased the tumor volume compared with the control group in a HNSCC xenograft mouse model[(3.12±0.75)mm^(3) vs.(189.02±17.54)mm^(3),P<0.001].Conclusions:The concurrent re-expression of DIRAS3 and p53 is a more effective approach to HNSCC treatment than current treatment strategies.展开更多
Quasinormal modes （QNMs） for Dirac perturbations off（R） black holes （BHs） are described in this paper, involving two types of f（R） solution： f（R） （Sehwarzschild） BHs and f（R） （Maxwell） BHs. With the f...Quasinormal modes （QNMs） for Dirac perturbations off（R） black holes （BHs） are described in this paper, involving two types of f（R） solution： f（R） （Sehwarzschild） BHs and f（R） （Maxwell） BHs. With the finite difference method, the stability of the f（R） black holes （BHs） is analysed and the threshold range off（R） （Schwarzschild） BHs and f（R） （Maxwell） BHs is defined respectively. The results show that due to the presence of the correction factor Ro, the damping rate of Dirac field decreases. Meanwhile, the influence of angular quantum number values [k] on the f（R） BHs is investigated. The results indicate that the QNMs oscillation becomes tenser and damping speed slowly decreases with ]k[ increasing. Furthermore, under the Dirac perturbation, the stability off（R） solutions can be reflected in the manner of Dirac QNMs. The relationships between the QNMs and the parameters （]k], charge Q and mass m） are discussed in massless, and massive cases, by contrast to the classical BHs.展开更多
基金supported by Funding for the Basic Research of the Ministry of Sciences and Technology,Sichuan Province(2015JY0090)the National Natural Science Foundation of China(81972546,81602373)。
文摘Background:p53 and DIRAS3 are tumor suppressors that are frequently silenced in tumors.In this study,we sought to determine whether the concurrent re-expression of p53 and DIRAS3 could effectively induce head and neck squamous cell carcinoma(HNSCC)cell death.Methods:CAL-27 and SCC-25 cells were treated with Ad-DIRAS3 and rAd-p53 to induce re-expression of DIRAS3 and p53 respectively.The effects of DIRAS3 and p53 re-expression on the growth and apoptosis of HNSCC cells were examined by TUNEL assay,flow cytometric analysis and MTT.The effects of DIRAS3 and p53 re-expression on Akt phosphorylation,oncogene expression,and the interaction of 4 E-BP1 with eIF4 E were determined by real-time PCR,Western blotting and immunoprecipitation analysis.The ability of DIRAS3 and p53 re-expression to induce autophagy was evaluated by transmission electron microscopy,LC3 fluorescence microscopy and Western blotting.The effects of DIRAS3 and p53 re-expression on HNSCC growth were evaluated by using an orthotopic xenograft mouse model.Results:TUNEL assay and flow cytometric analysis showed that the concurrent re-expression of DIRAS3 and p53 significantly induced apoptosis(P<0.001).MTT and flow cytometric analysis revealed that DIRAS3 and p53 reexpression significantly inhibited proliferation and induced cell cycle arrest(P<0.001).Mechanistically,the concurrent re-expression of DIRAS3 and p53 down-regulated signal transducer and activation of transcription 3(STAT3)and upregulated p21WAF1/CIP1 and Bax(P<0.001).DIRAS3 and p53 re-expression also inhibited Akt phosphorylation,increased the interaction of eIF4 E with 4 E-BP1,and reduced the expression of c-Myc,cyclin D1,vascular endothelial growth factor(VEGF),fibroblast growth factor(FGF),epidermal growth factor receptor(EGFR)and Bcl-2(P<0.001).Moreover,the concurrent re-expression of DIRAS3 and p53 increased the percentage of cells with GFP-LC3 puncta compared with that in cells treated with control adenovirus(50.00%±4.55%vs.4.67%±1.25%,P<0.001).LC3 fluorescence microscopy and Western blotting further showed that DIRAS3 and p53 re-expression significantly promoted autophagic activity but also inhibited autophagic flux,resulting in overall impaired autophagy.Finally,the concurrent re-expression of DIRAS3 and p53 significantly decreased the tumor volume compared with the control group in a HNSCC xenograft mouse model[(3.12±0.75)mm^(3) vs.(189.02±17.54)mm^(3),P<0.001].Conclusions:The concurrent re-expression of DIRAS3 and p53 is a more effective approach to HNSCC treatment than current treatment strategies.
基金Supported by FAPESP No.2012/08934-0National Natural Science Foundation of China under Grant Nos.11205254,11178018,11375279,11605015+1 种基金the Natural Science Foundation Project of CQ CSTC 2011BB0052the Fundamental Research Funds for the Central Universities 106112016CDJXY300002 and CDJRC10300003
文摘Quasinormal modes （QNMs） for Dirac perturbations off（R） black holes （BHs） are described in this paper, involving two types of f（R） solution： f（R） （Sehwarzschild） BHs and f（R） （Maxwell） BHs. With the finite difference method, the stability of the f（R） black holes （BHs） is analysed and the threshold range off（R） （Schwarzschild） BHs and f（R） （Maxwell） BHs is defined respectively. The results show that due to the presence of the correction factor Ro, the damping rate of Dirac field decreases. Meanwhile, the influence of angular quantum number values [k] on the f（R） BHs is investigated. The results indicate that the QNMs oscillation becomes tenser and damping speed slowly decreases with ]k[ increasing. Furthermore, under the Dirac perturbation, the stability off（R） solutions can be reflected in the manner of Dirac QNMs. The relationships between the QNMs and the parameters （]k], charge Q and mass m） are discussed in massless, and massive cases, by contrast to the classical BHs.
