miR-26a靶向调控AP-2γ表达对神经母细胞瘤细胞增殖的影响

[目的]探讨miR-26a是否可通过靶向调控AP-2γ表达而抑制神经母细胞瘤细胞增殖.[方法]通过双荧光素酶基因分析检测miR-26a对AP-2γ 3＇非编码区（3＇UTR）-荧光素酶的影响;采用Western blot方法检测miR-26a模拟物转染神经母细胞瘤细胞中AP 2γ表达水平;将AP-2γ shRNA转染SK-N AS细胞,MTS细胞增殖活性检测分析干扰AP-2γ表达对神经母细胞瘤细胞增殖能力.[结果]双荧光素酶活性检测显示miR-26a特异性地与AP-2γ的3＇UTR结合,抑制其荧光素酶活性.过表达miR-26a的神经母细胞瘤细胞AP2γ蛋白表达水平降低;shRNA干扰AP-2γ表达能抑制SK-N-AS细胞的增殖能力.[结论]miR-26a通过靶向调控AP-2γ表达而抑制神经母细胞瘤细胞的增殖.     

SUMO-1在HIF-1/VEGF信号通路中作用

目的研究SUMO-1在低氧激活的HIF-1/VEGF信号通路中作用。方法构建稳定表达SUMO-1的细胞系,采用荧光显微镜观察SUMO-1的细胞内定位,利用Western blot检测在低氧培养细胞中SUMO-1和HIF-1α的表达;利用荧光素酶报告基因实验检测SUMO-1对依赖于HIF-1的报告基因表达的影响。结果 SUMO-1主要分布在细胞核中,低氧可以上调SUMO-1的表达,SUMO-1可以上调HIF-1α的表达,促进依赖于HIF-1的荧光素酶报告基因的表达。结论低氧可能通过上调细胞中SUMO-1的表达,进而稳定HIF-1α或者上调HIF-1α的表达,增强HIF-1的转录活性。     

PML-RARα对环腺苷酸诱导急性髓系白血病细胞分化的影响

为了进一步探讨环腺苷酸cAMP协同低剂量氧化砷诱导急性早幼粒白血病细胞分化的分子机制，以稳定转染了PML—RARα融合基因的PR9细胞为实验对象，通过观察细胞的生长，并利用形态学实验、流式细胞技术和荧光素酶报告基因转染实验等检测cAMP和／或氧化砷处理前后细胞相关指标的变化，研究PML-RARα在cAMP诱导AML细胞分化过程中的作用。结果显示，虽然cAMP单独能使表达PML-RARα的PR9细胞表面分化抗原CD11b的阳性率有所升高；但细胞形态学分析表明，cAMP单用无法诱导表达PML—RARα融合蛋白的PR9细胞分化，只有联合氧化砷才能使细胞表现出完全分化的特征，并伴有CD11b表达的显著升高。此外，PML—RARα还可以明显抑制含有cAMP反应元件的报告基因的转录。结论：PML—RARα融合蛋白对cAMP诱导AML细胞分化的信号转导途径具有显著的抑制作用。     

Polymer genomics: shifting the gene and drug delivery paradigms.

Pluronic, the A-B-A amphiphilic block copolymers of poly(ethylene oxide) and poly(propylene oxide), can up-regulate the expression of selected genes in cells and alter genetic responses to antineoplastic agents in cancer. Two key new findings are discussed in relation to current drug and gene delivery strategies. First, these block copolymers alone and in combination with a polycation, polyethyleneimine, can up-regulate the expression of reporter genes in stably transfected cells. This underscores the ability of selected synthetic polymers to enhance transgene expression through a mechanism that augments improved DNA delivery into a cell. Second, although, when used alone, Pluronic is "genetically benign," when combined with an antineoplastic agent, doxorubicin, it drastically alters pharmacogenomic responses to this agent and prevents the development of multidrug resistance in breast cancer cells. Collectively, these studies propose the need for a thorough assessment of pharmacogenomic effects of polymer therapeutics to maximize the clinical outcomes and understand the pharmacological and toxicological effects of polymer-based drugs and delivery systems.     

利用CRISPR/Cas9技术建立SOST荧光报告基因i PSCs细胞系

目的利用CRISPR/Cas9技术构建硬骨素(SOST)基因荧光报告诱导性多能干细胞(i PSCs)细胞株。方法使用PCR检测i PSCs分化过程不同阶段成骨基因的表达。利用CRISPR/Cas9基因编辑技术将p2A-td TomatoNeo质粒转染至i PSCs细胞。使用PCR凝胶电泳检测转染的效果,而后分别在光镜下观察成骨不同阶段i PSCs的形态变化、茜素红染色及SOST-td Tomato荧光表达情况,并利用茜素红染色及PCR评估转染细胞的成骨效果及成骨基因表达情况。结果 PCR检测结果发现,SOST只在骨细胞中稳定表达,可作为骨细胞的标志性基因。利用CRISPR/Cas9技术将td Tomato插入到SOST终止密码子处,转染后的i PSCs细胞株不影响其成骨效果及SOST基因的表达。结论利用CRISPR/Cas9技术能够成功构建td Tomato-SOST荧光报告基因的i PSCs细胞株。     

Human small cell lung cancer cell lines expressing the proopiomelanocortin gene have aberrant glucocorticoid receptor function.

Some human small cell lung carcinomas (SCLC) secrete proopiomelanocortin (POMC) derived peptides, but in contrast to the pituitary, glucocorticoids fail to inhibit this hormone production. We have previously described an in vitro model using human SCLC cell lines that express POMC and are resistant to glucocorticoids. We have now identified the glucocorticoid receptor (GR) in the SCLC cell line COR L24 using a whole cell ligand binding assay (Kd = 5.7 nM; Bmax = 11 fmol/million cells), while another cell line, DMS 79, lacked significant glucocorticoid binding. To analyze GR function both positive (GMCO) and negative (TRE)3-tkCAT), glucocorticoid-regulated reporter gene constructs were transfected into COR L24 cells. In the SCLC cell line, neither hydrocortisone nor dexamethasone (500-2,000 nM) significantly induced chloramphenicol acetyltransferase expression from GMCO; in addition, they did not suppress chloramphenicol acetyltransferase expression from (TRE)3-tkCAT. Similar results were obtained with two other POMC-expressing SCLC cell lines. Expression of wild type GR in COR L24 cells restored glucocorticoid signaling, with marked induction of GMCO reporter gene expression by dexamethasone (9,100 +/- 910%; n = 3), and an estimated EC50 of 10 nM. This failure of the GR explains the resistance of the POMC gene to glucocorticoid inhibition and may have implications for cell growth in SCLC.