3,4,5-三羟基苯甲酸通过线粒体途径诱导人肝癌细胞SMMC-7721的凋亡

采用四甲基偶氮唑盐(MTT)观察3,4,5-三羟基苯甲酸(TBA)对人肝癌SMMC-7721细胞的增殖抑制作用; 通过流式细胞仪检测细胞凋亡、细胞内活性氧(ROS)及线粒体膜电位的变化, 用比色法测定Caspase-9和Caspase-3蛋白活性, 探讨TBA 诱导SMMC-7721细胞凋亡的分子机制. 研究结果表明, TBA对SMMC-7721细胞生长具有显著的抑制作用并诱导其凋亡, 诱导SMMC-7721细胞凋亡作用可能通过线粒体信号传导通路实现.     

HIV-1整合酶的RNA适配子的筛选及活性研究

通过SELEX技术已经筛选到了多种HIV-1病毒相关蛋白,如：逆转录酶、Rev和Tat蛋白、核壳蛋白等的核酸适配子,然而以HIV-1整合酶为靶点的DNA或RNA适配子却鲜有报道．在结合缓冲液中以10mmol．L-1的Mg2＋作为辅助因子,加入100mmol．L-1KCl筛选到了三个具有相似结构和托的适配子IN1,IN2和IN3．亲和力最高的适配子IN1的Kd为145nmol．L-1,保守区富含乌嘌呤碱基（G）,缺失任何一个茎环结构会使亲和力减弱．缺失右端固定序列的IN1-L的Kd为283nmol．L-1,虽然不能形成四链结构但可以被G-四链T40214竞争结合,可能与T40214具有相同的结合位点．     

氨基酸羟胺钒配合物的合成、表征及对PTP1B酶的抑制活性

合成了2种羟胺氧钒配合物--缬(亮)氨酸羟胺氧钒, 并通过元素分析、红外光谱、紫外光谱、热重分析及X射线单晶衍射对其结构进行了表征. 采用PTP1B酶筛选模型评价了它们及相关配合物的PTP1B酶抑制活性. 实验结果表明, 这2种配合物同属于三斜晶系, P1空间群, 中心钒原子与7个配位的氮氧原子形成扭曲的五角双锥构型, 进而通过氢键作用形成三维晶体结构. 这2种配合物对PTP1B酶都表现出抑制活性, 亮氨酸羟胺氧钒在浓度为20 μg/mL时对PTP1B酶的抑制率达到90.51%.     

金属离子对HIV-1整合酶与硫氮硫扎平抑制剂作用模式影响的分子模拟研究

HIV-1整合酶（IN）通过依赖金属离子的两步反应将病毒DNA整合入宿主细胞过程中。结合于HIV-1上的金属离子个数的变化直接影响整合酶与抑制剂之间的结合。本工作用同源模建方法搭建了每条单链核心区具有两个Mg2+ 的（2Mg-IN-Core）和具有一个Mg2+ 的HIV-1 IN二聚体核心区模型（1Mg-IN-Core）。分子对接分别得到它们与硫氮硫扎平类化合物能量较低的复合物结构,把对接结果进行了比较。研究发现：当整合酶中结合的Mg2+个数改变时,它与抑制剂的结合模式也会发生很大的变化;抑制剂能够特异的且稳定的与2Mg-IN-Core模型的活性位点结合;同时与ASP64和GLU152螯合的那个Mg2+离子对于硫氮硫扎平抑制剂与整合酶上的结合有很大的影响。2Mg-IN-Core模型与抑制剂的复合物平均结构进行了2000 ps的 分子动力学模拟,分析发现同时与ASP64及ASP116螯合的Mg2+与IN蛋白形成了四个稳定的螯合键;同时与ASP64及GLU152螯合的Mg2+可与IN结合、也可与抑制剂形成稳定的配位键,这个Mg2+对IN与硫氮硫扎平抑制剂之间的结合有较大影响。     

SOD酶模型配合物的合成及催化歧化作用——1,3,4-噻二唑类希夫碱配合物的合成、表征及对超氧离子的抑制作用

合成了2－氨基－5－巯基－1，3，4－噻二唑缩2，4－二羟基苯甲醛及其与Cu(Ⅱ），Co（Ⅱ），Zn（Ⅱ）的配合物，通过元素分析、摩尔电导、IR及其电子光谱对其组成和结构进行了表征。活性实验表明，配合物均对超氧离子有一定的抑制效果。     

Inhibitory Effects of Phenylacetic Acid on Proliferation of Human Pancreatic Carcinoma BXPC-3 Cells by the Regulation of Adenosine Deaminases Acting on RNA

The effect and mechanism of phenylacetic acid on the proliferation of pancreatic carcinoma cells were investigated in cultured pancreatic carcinoma BXPC-3 cells by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry assay.The results show that the treatment of pancreatic carcinoma cells with phenylacetic acid significantly inhibited the cell proliferation in time-dependent and dose-dependent manners.The proliferation of BXPC-3 cells was inhibited at the stage of S phase,the cells at the end stage of S phase were accumulated abundantly,and thus DNA synthesis could not be accomplished entirely.In addition,the expression of adenosine deaminases acting on RNA(ADARs) mRNA in BXPC-3 cells and pancreatic carcinoma specimen were detected by RT-PCR.Having been treated with phenylacetic acid,ADAR2 mRNA in BXPC-3 cells was significantly decreased,the differences were of statistical significance(P0.01).Taken together,these results suggest that phenylacetic acid may likely regulate the proliferation of pancreatic carcinoma cells through the regulation of ADAR2 mRNA expression.     

Probing the Adhesion of Hepatocellular Carcinoma HepG2 and SK‐Hep‐1 Cells

Carcinoma cell differentiation stage is an important indicator of cell behavior. For example, cell mobility is much higher for poorly‐differentiated hepatocellular carcinoma SK‐Hep‐1 cells than for well‐differentiated HepG2 cells. In this study, we have cultured HepG2 and SK‐Hep‐1 cells on chemically patterned polydimethylsiloxane (PDMS) substrates to observe differences in the adhesion properties and cell structure that occur due to the patterns. Both cell lines showed a preference for the hydrophobic regions on the patterned PDMS surface with SK‐Hep‐1 cells achieving a higher density than HepG2 for the same cell‐count solutions. Further, SK‐Hep‐1 cells adopted the square or hexagonal shape of the surface patterns while HepG2 cells maintained their more rounded shape. AFM force measurement arrays were also performed on the cell surfaces to measure and map adhesion values between the tip and cell surface membrane. These results demonstrate that, in addition to cell shape and size, adhesion expression in hepatocellular carcinoma cells is differentiation stage dependent. Further, the ability of the SK‐Hep‐1 cells to adopt the shape of the substrate pattern indicates they are more structurally labile, which may contribute to their higher mobility.     

Inhibitory Effects of Mistletoe Alkali on Salivary Adenoid Cystic Carcinoma Cells

Mistletoe alkali plays an important role in salivary adenoid cystic carcinoma(SACC) cell proliferation, apoptosis and invasion. Mistletoe alkali shows potent anticaner property. In this paper,immunocytochemical and immunofluorescence staining were employed to evaluate the expression levels of proliferating cell nuclear antigen(PCNA), Caspase 3, Caspase 8 and Caspase 9. Apoptosis was detected by acridine orange/ethidium bromide (AO/EB) staining, cell invasion ability was assessed by Boyden Chamber assay. Pretreatment with mistletoe alkali markedly decreased PCNA expression in SACC cells in a dose-dependent manner(P<0.001) and also led to increase the expression of Caspase 3, Caspase 8 and Caspase 9 in SACC cells compared with control group(P<0.001). Number of apoptotic cells increased dramatically in mistletoe alkali group(P<0.001). In Boyden Chamber assay, mistletoe alkali treatment could inhibit SACC cells to penetrate the artificial basement membrane compared with control group(P<0.01). Mistletoe alkali remarkably inhibited the proliferation and invasion of SACC cells and induced the apoptosis of SACC cells. These results provide an insight into the mechanisms of anticancer effects of mistletoe alkali, and highlight the potential clinical application of it.     

Novel Bradykinin Receptor Inhibitors Inhibit Proliferation and Promote the Apoptosis of Hepatocellular Carcinoma Cells by Inhibiting the ERK Pathway

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. Studies have shown that bradykinin (BK) is highly expressed in liver cancer. We designed the novel BK receptor inhibitors J051-71 and J051-105, which reduced the viability of liver cancer cells and inhibited the formation of cancer cell colonies. J051-71 and J051-105 reduced cell proliferation and induced apoptosis in HepG2 and BEL-7402 cells, which may be due to the inhibition of the extracellular regulated protein kinase (ERK) signaling pathway. In addition, these BK receptor inhibitors reversed the cell proliferation induced by BK in HepG2 and BEL-7402 cells by downregulating B1 receptor expression. Inhibiting B1 receptor expression decreased the protein levels of p-ERK and reduced the malignant progression of HCC, providing a potential target for HCC therapy.     

Expression of integrin beta1 and its roles on adhesion between different cell cycle hepatocellular carcinoma cells (SMMC-7721) and human umbilical vein endothelial cells

To investigate expression of integrin β₁ and its roles on adhesion between different cell cycle hepatocellular carcinoma cell (HCC) and human umbilical vein endothelial cells (HUVEC), the synchronous G₁ and S phase HCC were achieved through thymine-2-deoxyriboside and colchicines sequential blockage method and double thymine-2-deoxyriboside blockage method, respectively. Expression of integrin β₁ on hepatocellular carcinoma cells was detected with flow cytometer. Further, the adhesive force of HCC to HUVEC and the role of integrin β₁ in this adhesive course were studied by micropipette aspiration technique. The results showed that percentage of each cyclic phases of the controlled HCC (non-synchronous) are: G₂+M phase, 11%; G₁ phase, 54%; S phase, 36%; the synchronous rates of G₁ and S phase HCC amount to 74 and 98%, respectively. The expressive fluorescent intensity of integrin β₁ in G₁ phase HCC is depressed significantly than the values of S phase and controlled HCC. Accordingly, the adhesive forces of G₁ phase HCC to HUVEC was significantly lower than the value of S phase cells (P<0.01), but it has no remarkable difference when compared the adhesive force values of S phase HCC with control; the contribution of integrin β₁ was about 50% in the adhesion of HCC to HUVEC. It suggested that HCC would be synchronized preferably in G₁ and S phase with thymine-2-deoxyriboside and colchicines, the adhesive molecule integrin β₁ expressed in a high lever in HCC and presented differences in vary cell cycle, and integrin β₁ played an important roles in adhesion of HCC to HUVEC. Possibly, S phase HCC take a great action in this adhesive course.     

基于表面等离子体子共振成像技术研究苏拉明和顺铂对肝癌细胞生长的抑制作用简

基于表面等离子体子共振成像(SPRi)技术提出了一种实时、非标记的新型抗癌药物药效评估方法. 以聚二甲基硅氧烷(PDMS)为材料,制作了包含微柱结构的微流控芯片作为流通反应池,配合自行设计组装的SPRi生物传感器完成肿瘤细胞的特异性捕获及检测,研究了苏拉明和顺铂对肝癌细胞HepG2的生长抑制作用. 同时引入辅助验证实验,即采用常规八肽胆囊收缩素(简称CCK-8)法测定上述药物对肝癌细胞增殖的抑制作用. SPRi检测结果表明,苏拉明和顺铂能抑制肿瘤细胞HepG2增殖并呈现剂量、时间依赖关系.     

Strong Inhibitory Effects of Antisense Probes on Gene Expression through Ultrafast RNA Photocrosslinking

We have reported the photochemical regulation of the intracellular antisense effect of antisense probes containing a photo‐responsive artificial nucleic acid, 3‐cyanovinylcarbazole nucleoside (^CNVK). Here we focus on the importance of the photocrosslinking rate on the inhibitory effect on gene expression using photocrosslinkable antisense probes (pcASOs). The inhibitory effect of pcASOs on GFP gene expression was dependent on the photocrosslinking rate of 3‐cyanovinylcarbazole with d ‐threoninol (^CNVD), ^CNVK, or psoralen. The ultrafast RNA photocrosslinking induced the formation of a thermally irreversible covalent bond between pcASOs and the target RNA. These ASOs strongly inhibited gene expression only when the photocrosslinking rate was faster than the random walk of branch migration. In addition, pcASOs containing ^CNVD or ^CNVK targeted the RNAs with secondary structures. These results indicate the regulatory effect of photocrosslinker and photoirradiation energy using pcASOs on the gene expression level.