硒化壳聚糖对NB4细胞作用的实验研究

应用MTT法、AO/EB荧光染色法和NBT还原法观察硒化壳聚糖对NB4肿瘤细胞株生长的影响。结果发现,硒化壳聚糖可有效地抑制NB4细胞生长,并呈量效、时效关系。经100 mg/L及以上剂量硒化壳聚糖作用后的细胞可明显出现核固缩、碎裂等凋亡形态改变。而经100 mg/L以下剂量硒化壳聚糖作用后,细胞可出现诱导分化成熟的表现。     

硒化壳聚糖抗K562细胞的实验研究

用MTT法和AO/EB荧光染色法观察了硒化壳聚糖对K 562肿瘤细胞株生长的影响。结果发现,硒化壳聚糖可有效地抑制K 562细胞生长,并呈量效、时效关系。经硒化壳聚糖作用后的细胞可明显出现核固缩、碎裂等凋亡形态改变。硒化壳聚糖可诱导K 562细胞凋亡,抑制其生长。     

单独和合用硒化壳聚糖与阿霉素对K562细胞作用的研究

应用MTT法和AO／EB荧光染色法观察单独和合用硒化壳聚糖与阿霉素对K562细胞株的影响,结果发现硒化壳聚糖和阿霉素均可有效地抑制K562细胞生长。且两药联合使用效果更佳。硒化壳聚糖可诱导细胞凋亡。两药合用诱导细胞凋亡效果更好。     

硒化壳聚糖抑制人早幼粒白血病细胞增殖的研究

为探讨硒化壳聚糖对体外培养人早幼粒白血病细胞增殖的抑制作用,用SRB法和集落形成法检测了药物对细胞增殖的抑制作用,流式法检测了细胞周期阻断作用。结果表明,25、50、100mg／L硒化壳聚糖作用HL60细胞48h对细胞有增殖抑制作用（P〈0．01）;50、100mg／L硒化壳聚糖作用细胞48h后,G0／G1期细胞数较对照组增加了14．9％-22．0％（P〈0．05）,S期细胞减少了14．3％～20．1％（P〈0．05）。可见硒化壳聚糖对人早幼粒白血病细胞增殖具有抑制作用。     

FITC标记重组灵芝免疫调节蛋白(rLz-8)在NB4细胞中的动态定位

实验发现, 重组灵芝免疫调节蛋白(rLz-8)可直接杀伤人急性早幼粒细胞白血病细胞株NB4. 利用异硫氰酸荧光素(FITC)标记rLz-8, 其相关的活性实验结果和晶体结构分析都表明, FITC没有影响rLz-8已知生物学功能. 通过激光共聚焦显微镜观察FITC-rLz-8在NB4细胞内的动态过程发现, FITC-rLz-8可识别细胞膜上的受体, 并可进入细胞质, 并最终富集在细胞核区域内. Annexin V-FITC双染检测结果显示, rLz-8对NB4细胞杀伤作用的可能机制是对NB4细胞凋亡的诱导作用, 在一定浓度范围内, 剂量与凋亡诱导率成正相关. 因此rLz-8能够诱导肿瘤细胞NB4发生凋亡的亚细胞学机制可定位在细胞核上.     

硒化壳聚糖对K 562和K 562/ADM作用的比较研究

应用MTT法和细胞集落形成率法观察了硒化壳聚糖对K562和K562／ADM肿瘤细胞株生长的影响，结果发现硒化壳聚糖可有效地抑制两种K562细胞生长，呈量效关系。同等剂量的硒化壳聚糖对K562细胞的作用强度高于对K562／ADM细胞。硒化壳聚糖对耐药的细胞株可产生抑制作用，若与化疗药合用则可减慢甚至部分逆转临床上K562细胞耐药性的发生。     

硒化合物诱导细胞凋亡的信号转导机制

从硒化合物诱导细胞凋亡及其机理阐明硒防治肿瘤的生物功能,是当今硒的生物无机化学与相关学科交叉的前沿。本文通过作者的研究工作及国内外有关工作介绍了活性氧（ROS）介导的硒化合物诱导细胞凋亡的信号转导机制,阐述了ROS作为信号分子的特性及硒化合物与ROS作用的化学基础。     

钌配合物稳定端粒DNA的作用及其诱导细胞凋亡分子机制的研究

端粒酶在肿瘤细胞中高表达,已经成为抗肿瘤药物的重要靶点,由于很多肿瘤细胞中富含G4-DNA,通过稳定G-四链体DNA的形成来抑制端粒酶的活性已成为抗癌药物的一个新策略. 本文设计了两种钌配合物,调查了这两种钌配合物稳定G4-DNA的能力,发现配合物2稳定端粒 G4-DNA的能力强于配合物1,配合物2能够诱导端粒 G4-DNA发生构型的转化,而配合物1不能诱导G4-DNA发生构型的转化,这项研究结果证明,钌配合物与G4-DNA的作用能力与配体的平面性有关. 在抗肿瘤活性方面,配合物2表现出更强的抗肿瘤活性,尤其是对HepG2细胞具有较强的抑制作用,推测其是以端粒酶为靶点发挥的抗肿瘤作用. 配合物2能够诱导肿瘤细胞凋亡,能诱导G1期细胞阻滞和DNA碎片的形成（细胞凋亡的特征）. 据此推测本论文设计的钌配合物是一个潜在的抗肿瘤药物.     

扇贝多肽经由aSMase-JNK通路抑制UVA诱导HaCaT细胞凋亡

建立紫外线A(UVA)辐射损伤HaCaT细胞的病理模型, 从酸性鞘磷脂酶-JNK信号通路的角度研究扇贝多肽(Polypeptide from Chlamys farreri, PCF)抑制UVA诱导HaCaT细胞凋亡的分子机制. 采用Hoechst 33258染色结合琼脂糖凝胶电泳分析细胞凋亡; 用RT-PCR法和细胞免疫荧光染色检测胞内酸性鞘磷脂酶(acid sphingomyelinase, aSMase)的表达; 蛋白印迹法检测细胞内JNK及磷酸化JNK的蛋白水平. 结果表明, PCF可明显地抑制UVA诱导的HaCaT细胞凋亡; aSMase抑制剂Desipramine和JNK抑制剂SP600125均可阻断UVA引起的细胞凋亡; PCF的浓度在1.42~5.68 mmol/L范围内可依赖性地抑制UVA辐射后细胞内aSMase的表达量以及JNK蛋白的磷酸化; 预先加入Desipramine则抑制UVA引起的JNK蛋白的磷酸化. 表明PCF通过阻断aSMase-JNK通路来抑制UVA诱导HaCaT细胞凋亡.     

富勒烯衍生物对神经细胞的凋亡作用

机体代谢中产生的氧自由基可诱导生物细胞大分子发生破坏，导致细胞发生非程序性凋亡。特别是神经细胞，担负着接受且产生神经冲动从而支配全身活动的功能，而且有关研究已经表明一些神经退化及紊乱疾病与细胞产生氧自由基有关。富勒烯衍生物作为新型的具有高度吸收自由基活性的一种抗氧化剂，最有潜力用作神经细胞的保护剂。本文介绍了富勒烯衍生物作用的机理及近几年富勒烯衍生物阻断凋亡信号及阻止氧自由基对神经细胞破坏作用的研究进展。     

Effects of oxymatrine on proliferation and apoptosis in human hepatoma cells

Oxymatrine, a natural quinolizidine alkaloid, has been known having cytotoxic and chemopreventive effects on various cancer cells. To investigate the possible mechanism of oxymatrine's role on cancer cells, in the present study, we examined further the effects of oxymatrine on the growth, proliferation, apoptosis and expression of bcl-2 and p53 gene in human hepatoma SMMC-7721 cells in vitro. Our results show that oxymatrine notably inhibits the growth and proliferation of SMMC-7721 cells and it present a dose-dependence and time-dependence manner within definite reacting dose and time. Oxymatrine block SMMC-7721 cells in G2/M and S phase; prevent cells entering into G0/G1 phase. It results in an obvious accumulation of G2/M and S phase cells while decrease of G0/G1 phase cells. Oxymatrine induce apoptosis of SMMC-7721 cells and apoptotic rate amount to about 60% after treatment with 1.0 mg/ml oxymatrine for 48 h. We also find that oxymatrine down-regulate expression of bcl-2 gene while up-regulate expression of p53 gene. These results demonstrate that oxymatrine inhibit the proliferation and induce apoptosis of human hepatoma SMMC-7721 cells, and suggest that this effect was mediated probably by a significant cell cycle blockage in G2/M and S phase, down-regulation of bcl-2 and up-regulation of p53.     

Janerin Induces Cell Cycle Arrest at the G2/M Phase and Promotes Apoptosis Involving the MAPK Pathway in THP-1, Leukemic Cell Line

Janerin is a cytotoxic sesquiterpene lactone that has been isolated and characterized from different species of the Centaurea genus. In this study, janerin was isolated form Centaurothamnus maximus, and its cytotoxic molecular mechanism was studied in THP-1 human leukemic cells. Janerin inhibited the proliferation of THP-1 cells in a dose-dependent manner. Janerin caused the cell cycle arrest at the G2/M phase by decreasing the CDK1/Cyclin-B complex. Subsequently, we found that janerin promoted THP-1 cell death through apoptosis as indicated by flow cytometry. Moreover, apoptosis induction was confirmed by the upregulation of Bax, cleaved PARP-1, and cleaved caspase 3 and the downregulation of an anti-apoptotic Bcl-2 biomarker. In addition, immunoblotting indicated a dose dependent upregulation of P38-MAPK and ERK1/2 phosphorylation during janerin treatment. In conclusion, we have demonstrated for the first time that janerin may be capable of inducing cell cycle arrest and apoptosis through the MAPK pathway, which would be one of the mechanisms underlying its anticancer activity. As a result, janerin has the potential to be used as a therapeutic agent for leukemia.     

Pogostemon cablin Triggered ROS-Induced DNA Damage to Arrest Cell Cycle Progression and Induce Apoptosis on Human Hepatocellular Carcinoma In Vitro and In Vivo

The purpose of the study was to elucidate the anti-hepatoma effects and mechanisms of Pogostemon cablin essential oils (PPa extract) in vitro and in vivo. PPa extract exhibited an inhibitory effect on hepatocellular carcinoma (HCC) cells and was less cytotoxic to normal cells, especially normal liver cells, than it was to HCC cells, exerting a good selective index. Additionally, PPa extract inhibited HCC cell growth by blocking the cell cycle at the G₀/G₁ phase via p53 dependent or independent pathway to down regulated cell cycle regulators. Moreover, PPa extract induced the FAS-FASL-caspase-8 system to activate the extrinsic apoptosis pathway, and it increased the bax/bcl-2 ratio and reduced ΔΨm to activate the intrinsic apoptosis pathway that might be due to lots of reactive oxygen species (ROS) production which was induced by PPa extract. In addition, PPa extract presented to the potential to act synergistically with sorafenib to effectively inhibit HCC cell proliferation through the Akt/mTOR pathway and reduce regrowth of HCC cells. In an animal model, PPa extract suppressed HCC tumor growth and prolonged lifespan by reducing the VEGF/VEGFR axis and inducing tumor cell apoptosis in vivo. Ultimately, PPa extract demonstrated nearly no or low system-wide, physiological, or pathological toxicity in vivo. In conclusion, PPa extract effectively inhibited HCC cell growth through inducing cell cycle arrest and activating apoptosis in vitro and in vivo. Furthermore, PPa extract exhibits less toxicity toward normal cells and organs than it does toward HCC cells, which might lead to fewer side effects in clinical applications. PPa extract may be developed into a clinical drug to suppress tumor growth or functional food to prevent HCC initiation or chemoprotection of HCC recurrence.     

Components of rhizome extract of Cnidium officinale Makino and their in vitro biological effects

The anti-inflammatory and anticancer activities of a methanol extract of the rhizome of Cnidium officinale were investigated. Four compounds, namely falcarindiol (1), 6-hydroxy-7-methoxy-dihydroligustilide (2), ligustilidiol (3), and senkyunolide H (4) were isolated from the extract of the rhizome of Cnidium officinale and their structures were elucidated by analysis of their spectroscopic data and by comparison with previously reported data. These compounds showed anti-inflammatory activities, measured as inhibition of nitric oxide (NO) release in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells, with IC(50) values of 4.31 ± 5.22, 152.95 ± 4.23, 72.78 ± 5.13, and 173.42 ± 3.22 μM, respectively. They also inhibited inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expression induced by LPS. Among these compounds, falcarindiol (1) was found to have anti-proliferative effect against MCF-7 human breast cancer cells by induction of a G(0)/G(1) cell cycle block of the cells, with an IC(50) value of 35.67 μM. Typical apoptotic effects were observed by phase contrast microscopy and were also exhibited in fluorescence microscopy with Hoechst 33342 staining. In addition, falcarindiol induced apoptosis through strongly increased mRNA expression of Bax and p53, and slightly reduced Bcl-2 mRNA levels in a dose dependent manner. This study suggested that C. officinale extract and its components would be valuable candidates in therapeutic applications for anti-inflammatory and anti-cancer agents.     

Hypericin-mediated photocytotoxic effect on HT-29 adenocarcinoma cells is reduced by light fractionation with longer dark pause between two unequal light doses

The present study demonstrates the in vitro effect of hypericin-mediated PDT with fractionated light delivery. Cells were photosensitized with unequal light fractions separated by dark intervals (1 or 6 h). We compared the changes in viability, cell number, survival, apoptosis and cell cycle on HT-29 cells irradiated with a single light dose (12 J/cm(2)) to the fractionated light delivery (1 + 11 J/cm(2)) 24 and 48 h after photodynamic treatment. We found that a fractionated light regime with a longer dark period resulted in a decrease of hypericin cytotoxicity. Both cell number and survival were higher after light sensitization with a 6-h dark interval. DNA fragmentation occurred after a single light-dose application, but in contrast no apoptotic DNA formation was detected with a 6-h dark pause. After fractionation the percentage of cells in the G1 phase of the cell cycle was increased, while the proportion of cells in the G2 phase decreased as compared to a single light-dose application, i.e. both percentage of cells in the G1 and G2 phase of the cell cycle were near control levels. We presume that the longer dark interval after the irradiation of cells by first light dose makes them resistant to the effect of the second illumination. These findings confirm that the light application scheme together with other photodynamic protocol components is crucial for the photocytotoxicity of hypericin.     

β-Cyclodextrin/glycyrrhizic acid functionalised quantum dots selectively enter hepatic cells and induce apoptosis

The use of active components from important medical herbs has proved effective in treating various cancers. Glycyrrhizic acid (GA) is one of the many interesting triterpenoic acids with anticancerogenic potential, and is known to trigger apoptosis in hepatocarcinoma cells. In this study we combined quantum dots (QDs) with GA in the presence of β‐cyclodextrin (β‐CD), and prepared β‐CD/GA‐functionalised QDs, which led to improved antitumor activity and induced apoptosis in hepatocarcinoma cells. These compounds showed a better selectivity for hepatic cells compared to HeLa and ECV‐304 cells. Hoechst and annexin V–FITC staining and mitochondrial membrane potential (MMP) experiments proved an apoptotic effect of these compounds on HepG2 cells. At the same time, transmission electron microscopy (TEM) showed obvious features of apoptosis, for example, irregularities of nuclear shapes, mitochondria swelling, clumping and peripheral chromatin condensation, zeiosis or blebbing of the plasma membrane and formation of apoptotic bodies. It is notable that β‐CD/GA‐functionalised QDs showed effective cell growth inhibition by triggering G0/G1 phase arrest and inducing apoptosis through an reactive oxygen species mediated mitochondrial dysfunction pathway. β‐CD/GA‐functionalised QDs primarily induced apoptotic response in a time‐ and dose‐dependent manner, but little apoptosis appeared with L ‐Cys‐β‐CD‐functionalised QDs or GA alone. These studies suggest that β‐CD/GA‐functionalised QDs have therapeutic potential against cancer.     

Role of p21CIP1 as a determinant of SC-560 response in human HCT116 colon carcinoma cells

SC-560, a structural analogue of celecoxib, induces growth inhibition in a wide range of human cancer cells in a cyclooxygenase (COX)-independent manner. Since SC-560 suppresses the growth of cancer cells mainly by inducing cell cycle arrest, we sought to examine the role of p21CIP1, a cell cycle regulator protein, in the cellular response against SC-560 by using p21(+/+) and p21(-/-) isogenic HCT116 colon carcinoma cells. In HCT116 (p21(+/+)) cells, SC-560 dose-dependently induced growth inhibition and cell cycle arrest at the G1 phase without significant apoptosis induction. SC-560-induced cell cycle arrest was accompanied by upregulation of p21CIP1. However, the extent of SC-560-induced accumulation at the G1 phase was approximately equal in the p21(+/+) and the p21(-/-) cells. Nonetheless, the growth inhibition by SC-560 was increased in p21(-/-) cells than p21(+/+)cells. SC-560-induced reactive oxygen species (ROS) generation did not differ between p21(+/+) and p21(-/-) cells but the subsequent activation of apoptotic caspase cascade was more pronounced in p21(-/-) cells compared with p21(+/+) cells. These results suggest that p21CIP1 blocks the SC-560-induced apoptotic response of HCT116 cells. SC-560 combined with other therapy that can block p21 CIP1 expression or function may contribute to the effective treatment of colon cancer.