高糖通过线粒体途径诱导成骨细胞凋亡

线粒体途径是细胞凋亡的重要途径之一. 在特定的刺激下,例如高糖条件,可以通过caspase依赖性和非依赖性两种途径诱导多种细胞凋亡.但线粒体凋亡途径在高糖引起成骨细胞凋亡中所起的作用,目前尚不清楚.本研究证明,高糖可以通过线粒体凋亡途径诱导成骨细胞凋亡.Annexin V-FITC/PI流式细胞学检测显示,高糖可诱导MC3T3-E1细胞凋亡.Western印迹检测发现,不同浓度D-葡萄糖（11,22,33 mmol/L）可以引起线粒体中Bax蛋白表达的增加,使Bax蛋白由细胞质中易位到线粒体,激活了线粒体凋亡途径.JC-1荧光探针检测证实,高糖处理成骨细胞后,线粒体膜电位明显降低,表明线粒体途径被激活.而细胞质中的细胞色素c、凋亡诱导因子（AIF）表达增加,细胞色素c和AIF从线粒体中释放到细胞质中,释放到细胞质中的细胞色素c使caspase-3、caspase-9剪切活化,从而激活了caspase依赖性凋亡途径.因此,线粒体凋亡途径可能是高糖诱导成骨细胞凋亡过程中一个重要的途径.     

Anthraquinone G503 Induces Apoptosis in Gastric Cancer Cells through the Mitochondrial Pathway

G503 is an anthraquinone compound isolated from the secondary metabolites of a mangrove endophytic fungus from the South China Sea. The present study elucidates the anti-tumor activity and the underlying mechanism of G503. Cell viability assay performed in nine cancer cell lines and two normal cell lines demonstrated that the gastric cancer cell line SGC7901 is the most G503-sensitive cancer cells. G503 induced SGC7901 cell death via apoptosis. G503 exposure activated caspases-3, -8 and -9. Pretreatment with the pan-caspase inhibitor Z-VAD-FMK and caspase-9 inhibitor Z-LEHD-FMK, but not caspase-8 inbibitor Z-IETD-FMK, attenuated the effect of G503. These results suggested that the intrinsic mitochondrial apoptosis pathway, rather than the extrinsic pathway, was involved in G503-induced apoptosis. Furthermore, G503 increased the ratio of Bax to Bcl-2 in the mitochondria and decreased the ratio in the cytosol. G503 treatment resulted in mitochondrial depolarization, cytochrome c release and the subsequent cleavage of caspase -9 and -3. Moreover, it is reported that the endoplasmic reticulum apoptosis pathway may also be activated by G503 by inducing capase-4 cleavage. In consideration of the lower 50% inhibitory concentration for gastric cancer cells, G503 may serve as a promising candidate for gastric cancer chemotherapy.     

大蒜素诱导人食管癌EC-109细胞凋亡

为寻找毒副作用小并且治疗效果好的抗癌药物,研究大蒜素对人食管癌EC-109细胞凋亡的影响,同时探讨了大蒜素引发细胞凋亡的可能机制。通过激光共聚焦显微镜观察细胞形态变化,琼脂糖凝胶电泳检测DNA片段化情况,流式细胞术检测细胞凋亡率和线粒体膜电位变化,qRT-PCR和Western blotting检测细胞凋亡相关基因Bax、Bcl-2的mRNA和蛋白表达水平。结果显示,大蒜素作用人食管癌EC-109细胞48 h后,线粒体膜电位显著降低,并且早期凋亡细胞和晚期凋亡细胞所占百分比均显著增加。同时,与对照组相比,Bax mRNA和蛋白水平均显著升高(p<0.05),Bcl-2 mRNA和蛋白水平均显著降低(p<0.05)。据此,本研究得出大蒜素可诱导人食管癌EC-109细胞凋亡,并呈剂量依赖性,有潜在的药用价值。     

抑制Hedgehog信号通路改变结肠癌细胞基因表达谱

Hedgehog（Hh）信号通路在机体发育和肿瘤发生中发挥着重要作用。在该研究中,Western blot检测三株结肠癌细胞Hedgehog信号通路组分的表达,结果表明三株结肠癌细胞中HT-29细胞Hedgehog信号通路组分较完整。采用MTT和BrdU法检测Hedgehog信号通路膜受体Smo特异性抑制剂环杷明和末端转录因子Gli1/2的特异性抑制剂GANT61对HT-29细胞的影响,提示这两种抑制剂均显著抑制HT-29细胞生存率和细胞增殖率,且GANT61比环杷明更敏感。表达谱芯片检测阻断Hedgehog信号通路后HT-29细胞基因谱的变化,结合生物信息学分析,揭示HT-29细胞经环杷明和GANT61处理后基因表达呈现抑制特征,其差异基因表达主要以下调为主,其中环杷明主要影响细胞内源刺激等,而GANT61主要影响代谢和类固醇合成,并与MAPK信号通路有关联,两者均能影响细胞免疫及凋亡相关通路。这些结果提示,Hh信号通路有可能作为结肠癌的治疗靶点。     

Apoptosis Induction by Wheat-flour Sphingoid Bases in DLD-1 Human Colon Cancer Cells

The apoptotic effects of plant sphingoid bases prepared from wheat-flour cerebroside on human colorectal cancer DLD-1 cells were examined. The viability of DLD-1 cells treated with such plant sphingoid bases was reduced in a dose-dependent manner and was similar to that of cells treated with sphingosine. Morphological changes such as condensed chromatin fragments were found, so those sphingoid bases reduced cell viability through causing apoptosis in these cells.     

青蒿素诱导人白血病细胞K562凋亡的线粒体机制

目的:探讨青蒿素诱导人白血病细胞K562凋亡的线粒体机制.方法:用青蒿素处理K562细胞.通过MTT比色法检别细胞增殖抑制的效果;荧光显微镜观察细胞的凋亡;流式细胞术(flow cytometry,FCM)进行细胞周期分析;Western-blotting测定药物作用前后线粒体、细胞浆细胞色素C的表达.结果:青蒿素抑制K562细胞的增殖,IC5D为1.5× 10-5mol·L-1;Hoechst33342/PI双荧光染色可观察到明显的核浓缩、凝集等细胞凋亡表现;流式细胞仪检测G2期细胞比例增高,S期减少;Western-blotting检测药物处理细胞后线粒体细胞色素C表达水平下调,细胞浆出现明显细胞色素C蛋白条带.结论:青蒿素可能通过线粒体细胞色素C途径诱导K562细胞凋亡.     

The Ganglioside GM3 Is Associated with Cisplatin-Induced Apoptosis in Human Colon Cancer Cells

Cisplatin (cis-diamminedichloroplatinum, CDDP) is a well-known chemotherapeutic agent for the treatment of several cancers. However, the precise mechanism underlying apoptosis of cancer cells induced by CDDP remains unclear. In this study, we show mechanistically that CDDP induces GM3-mediated apoptosis of HCT116 cells by inhibiting cell proliferation, and increasing DNA fragmentation and mitochondria-dependent apoptosis signals. CDDP induced apoptosis within cells through the generation of reactive oxygen species (ROS), regulated the ROS-mediated expression of Bax, Bcl-2, and p53, and induced the degradation of the poly (ADP-ribosyl) polymerase (PARP). We also checked expression levels of different gangliosides in HCT116 cells in the presence or absence of CDDP. Interestingly, among the gangliosides, CDDP augmented the expression of only GM3 synthase and its product GM3. Reduction of the GM3 synthase level through ectopic expression of GM3 small interfering RNA (siRNA) rescued HCT116 cells from CDDP-induced apoptosis. This was evidenced by inhibition of apoptotic signals by reducing ROS production through the regulation of 12-lipoxigenase activity. Furthermore, the apoptotic sensitivity to CDDP was remarkably increased in GM3 synthase-transfected HCT116 cells compared to that in controls. In addition, GM3 synthase-transfected cells treated with CDDP exhibited an increased accumulation of intracellular ROS. These results suggest the CDDP-induced oxidative apoptosis of HCT116 cells is mediated by GM3.     

High‐Performance and Uniform 1 cm2 Polymer Solar Cells with D1‐A‐D2‐A‐Type Random Terpolymers

For the commercial development of organic photovoltaics (OPVs), laboratory‐scale OPV technology must be translated to large area modules. In particular, it is important to develop high‐efficiency polymers that can form thick (>100 nm) bulk heterojunction (BHJ) films over large areas with optimal morphologies for charge generation and transport. Here, D₁‐A‐D₂‐A random terpolymers composed of 2,2′‐bithiophene with various proportions of 5,6‐difluoro‐4,7‐bis(thiophen‐2‐yl)‐2,1,3‐benzothiadiazole and 5,6‐difluoro‐2,1,3‐benzothiadiazole (FBT) are synthesized. It is found that incorporating small proportions of FBT into the polymer not only conserves the high crystallinity and favorable face‐on orientation of the D‐A copolymer FBT‐Th4 but also improves the nanoscale phase separation of the BHJ film. Consequently, the random terpolymer PDT2fBT‐BT10 exhibits a much improved solar cell efficiency of 10.31% when compared to that of the copolymer FBT‐Th4 (8.62%). Moreover, due to this polymer's excellent processability and suppressed overaggregation, OPVs with 1 cm² active area based on 351 nm thick PDT2fBT‐BT10 BHJs exhibit high photovoltaic performance of 9.42%, whereas rapid efficiency decreases arise for FBT‐Th4‐based OPVs for film thicknesses above 300 nm. It is demonstrated that this random terpolymer can be used in large area and thick BHJ OPVs, and guidelines for developing polymers that are suitable for large‐scale printing technologies are presented.