锯叶棕提取物对人脑胶质瘤细胞凋亡和PI3K蛋白表达影响的研究

目的：通过锯叶棕提取物对人脑胶质瘤细胞的干预,观察人脑胶质瘤细胞中细胞凋亡和PI3K蛋白表达的变化。方法体外培养U251细胞,应用锯叶棕提取物进行预处理,应用TUNEL法检测细胞凋亡,应用Western Blot法检测PI3K蛋白表达水平的变化。结果TUNEL法染色检测锯叶棕提取物对人脑胶质瘤细胞凋亡的影响,24 h与48 h均可见TUNEL阳性反应细胞即凋亡细胞,胞体缩小,形态不规则,胞核固缩浓染,呈棕黄色或棕褐色;1.5μL/mL组48 h与24 h比较,凋亡数量显著增多（P＜0.01）;对照组24 h与48 h偶见凋亡细胞,2.0μL/mL组与1.5μL/mL组比较,凋亡率增大（P＜0.01）。用Western blot法检测锯叶棕提取物对人脑胶质瘤细胞PI3K蛋白表达的影响,锯叶棕提取物预处理U251细胞与对照组比较, PI3K蛋白表达水平显著降低（P＜0.01）。结论锯叶棕提取物能诱导人脑胶质瘤细胞凋亡;锯叶棕提取物诱导人脑胶质瘤细胞凋亡的机制可能是通过阻断PI3K/Akt信号转导通路。     

Barrett食管发病机制研究进展

随着食管腺癌发病率的不断升高,Barrett食管(BE)越来越受到重视。BE相关研究已取得较大进展,但其具体发病机制仍未完全阐明。近来研究表明BE发生的分子机制与转录因子、信号蛋白、小分子RNA(miRNA)等密切相关。本文就BE发病机制的研究进展作一综述。     

Adeno-associated virus mediated gene transfer into lung cancer cells promoting CD40 ligand-based immunotherapy

Expression of the CD40 ligand (CD40L) on tumors can activate host immune systems and produce antitumor effects against the tumors. To deliver the CD40L gene efficiently, we evaluated the efficiency of transduction of different serotypes of adeno-associated virus (AAV) vectors in lung cancer A549 cells and compared the transduction efficiency of a conventional AAV vector with that of self-complementary AAV (scAAV) vectors as well. We determined that serotype AAV2/5 transduced A549 cells much more efficiently than serotypes AAV2/1, AAV2/2, AAV2/6, AAV2/7, AAV2/8, AAV2/9 and AAV2/10. And the transduction efficiency of scAAV2/5 was significantly higher than conventional AAV2/5. Furthermore, pre-treatment with carboplatin, which is a chemotherapeutic agent used in lung cancer chemotherapy, substantially increased AAV-mediated transgene expression. The scAAV2/5 vectors encoding human CD40L were used to tranduce CD40L into A549 cells, which were then co-cultivated with immature human dendritic cells (DCs). Interleukin 12 (IL-12) that was released was measured in the culture supernatant. Specificity of the immunostimulatory effect of CD40L was confirmed by blocking with a monoclonal antibody binding to human CD40L. The in vivo antitumor activity was evaluated in BALB/c nude mice bearing A549 lung cancer. scAAV2/5-CD40L showed significant inhibitory effects on the growth of transplanted tumor cells as compared with control group. These studies suggest that recombinant AAV2/5-CD40L may provide an effective form of therapy for lung cancer.     

Protein kinases in the regulation of apoptosis in B-cell chronic lymphocytic leukemia

The involvement of several protein kinase pathways in the regulation of apoptosis and cell survival has been analyzed in a wide range of models. This article reviews current understanding of the protein kinases involved in the control of apoptosis in B-cell chronic lymphocytic leukemia (B-CLL) cells. Protein kinase C (PKC), phosphatidylinositol 3-kinase (PI3K) and nuclear factor-kappa B (NF-κB) play important roles in the survival of these leukemic cells. These survival pathways affect proteins involved in the control of apoptosis by altering their expression or function. The elucidation of the signal transduction network involved in the survival of B-CLL cells could provide novel pharmacological targets for the therapy of B-CLL.     

The use of melittin to enhance transgene expression mediated by recombinant adeno-associated virus serotype 2 vectors both in vitro and in vivo

Objective: Melittin, a cell-penetrating peptide, improves the efficiency of many non-viral gene delivery vectors, yet its application in viral vectors has not been well studied. The non-pathogenic recombinant adeno-associated virus(rAAV) vector is an ideal in vivo gene delivery vector. However, its full potential will only be achieved after improvement of its transduction efficiency. To improve the transduction efficiency of rAAV2 vectors, we attempted to develop a melittin-based r AAV2 vector d...     

不同亚型Numb蛋白对肝纤维化相关信号通路的影响

肝纤维化是各种慢性肝病发展为肝硬化的必经之路,是一个可逆的病理状态。但如何阻抑或逆转肝纤维化的发生与发展,仍是临床需要解决的重要科学问题。Numb,一个重要的细胞命运决定子,已被发现与多种疾病的发生密切相关。在肝纤维化环境中,由于Numb基因的选择性剪切作用,翻译出不同亚型的Numb蛋白,其对不同信号通路的活化以及肝干细胞的分化具有不同的调节作用。目前关于Numb蛋白不同亚型在肝纤维化中的作用报道较少。综述了不同亚型Numb蛋白对Notch、Hedgehog、P53信号通路以及对肝干细胞的调控作用,阐释其在肝纤维化治疗中的潜在应用前景。     

Specific antibodies modulate the interactions of adenovirus type 5 with dendritic cells

Adenovirus type 5 (Ad5) is able to induce an efficient CD8+ T lymphocyte (CTL) response against a transgene product, a property thought to be linked to its ability to transduce dendritic cells (DCs). Little, however, is known about the capacity of Ad5 to interact with DCs in the presence of specific antibodies, although most people test positive for antibodies directed against Ad5. In the present study, we found that in the presence of Ad5 antibodies, a large fraction of Ad5 binds very efficiently to DCs, and that this binding is FcgammaRII/FcgammaRIII dependent. Nevertheless, in the presence of high levels of antibodies against the whole virion, Ad5 entry was inhibited. Increased binding led to increased entry in DCs in the presence of fiber-specific antibodies or in the presence of low amounts of a whole antiserum raised against whole virions, showing that the relative concentration of antibodies directed against fiber and penton base plays a major role in entry efficacy. Nevertheless, mice previously immunized with virions or purified fiber developed a lower transgene-specific CD8+ T cell response than naive mice, although their serum appeared to increase virus entry into DCs in vitro.