Elimination of central chemosensitivity by coagulation of a bilateral area on the ventral medullary surface in awake cats

Breathing and respiratory response to CO₂ were observed in 6 awake cats and 1 control before and after bilateral coagulation of the formerly described area S (Schläfke and Loeschcke, 1967) on the ventral medullary surface under hyperoxic conditions. Ventilation decreased,PCO₂ rose and CO₂ response was almost or completely abolished in 4 cats, and moderately reduced in 2 cats. Inhalation of CO₂ had an inhibitory effect on ventilation in two cases. In some instances the respiratory frequency was increased by CO₂. Periodic breathing as well as spotaneous hyperventilatron elicited by arousal indicate parallels to the Pickwickian or Ondine's curse syndrome. No respiratory changes were produced by a lesion on the pyramidal tract medial to the area S. It is concluded that central chemosensitivity can be eliminated within the superficial layer of the area S. The loss of CO₂ response seems to be correlated with complete destruction of the superficial nerve cells located within the area S (Petrovický, 1968) and degeneration within the ventral part of the nucleus paragigantocellularis.Supported by the Deutsche Forschungsgemeinschaft (SFB 114, Bionach)     

胰岛素对人宫颈癌Hela细胞化疗敏感性的影响

目的探讨胰岛素能否增强人宫颈癌Hela细胞对顺铂（DDP）的化疗敏感性及其相关机制。方法体外培养人宫颈癌Hela细胞株,MTr法检测5U／L胰岛素作用3、6、9、12、15、18、21h后,联合DDP（7．26mg／L）对人宫颈癌Hela细胞增殖抑制率的影响。流式细胞仪检测对照组、DDP组、胰岛素组及联合组（胰岛素化疗前作用6h）的细胞周期时相变化情况。结果DDP组、胰岛素化疗前作用不同时间组与对照组相比,Hela细胞的增殖抑制率明显上升（P〈0．01）;且胰岛素于化疗前提前作用3、6、9、12、15h后加入DDP,宫颈癌Hela细胞的增殖抑制率明显高于DDP组（P〈0．01）。流式分析显示DDP组及胰岛素组的S期细胞比例较对照组高（P均〈0．01）,联合组s期细胞比例较DDP组高（P〈0．01）。结论胰岛素具有较显著的DDP化疗增敏作用,胰岛素作用时机选择是胰岛素对宫颈癌细胞化疗增敏作用的关键。     

Paclitaxel-loaded glyceryl palmitostearate nanoparticles: in vitro release and cytotoxic activity

Solid lipid nanoparticles (SLNs) of paclitaxel using glyceryl palmitostearate (GPS) as matrix were prepared by modified hot homogenization method. The SLNs were characterized for mean particle size, percent entrapment efficiency, and zeta potential, which were found to be 207 nm, 96.26%, and ?28.26 mV, respectively. Transmission electron microscopic studies revealed that the prepared SLNs were of spherical shape. Drug retarding efficiency of the lipid (GPS) was better in pH 7.4 compared with pH 3.5. The release profile showed tendency to follow Higuchi diffusion pattern in both the media. Chemosensitivity assay carried out using B16F10 cell lines showed that antiproliferative activity of paclitaxel was not hindered because of encapsulation.     

Inhibition of Lon blocks cell proliferation,enhances chemosensitivity by promoting apoptosis and decreases cellular bioenergetics of bladder cancer: potential roles of Lon as a prognostic marker and therapeutic target in baldder cancer

ATP-dependent Lon protease within mitochondrial matrix contributes to the degradation of abnormal proteins. The oxidative or hypoxic stress which represents the stress phenotype of cancer leads to up-regulation of Lon. However, the role of Lon in bladder cancer remains undefined. Here, we found that Lon expression in bladder cancer tissues was significantly higher than those in noncancerous tissues; down-regulation of Lon in bladder cancer cells significantly blocked cancer cell proliferation via suppression c-Jun N-terminal kinase (JNK) phosphorylation due to decreased reactive oxygen species (ROS) production and enhanced the sensitivity of bladder cancer cells to chemotherapeutic agents by promoting apoptosis. We further found that Lon down-regulation in bladder cancer cells decreased cellular bioenergetics as determined by measuring aerobic respiration and glycolysis using extracellular flux analyzer. The tissue microarray (TMA) results showed that high expression of Lon was related to the T and TNM stage, as well as histological grade of bladder cancer patients. We also demonstrated that Lon was an independent prognostic factor for overall survival of bladder cancer. Taken together, our data suggest that Lon could serve as a potential diagnostic biomarker and therapeutic target for treatment of bladder cancer, as well as for prediction of the effectiveness of chemotherapy.     

MRP1及TopoⅡ的表达与肺癌耐药性的关系

目的探讨肺癌耐药机制及明确耐药基因与化疗药物耐药性的相关性研究。方法应用MTT法对顺铂（Cisplatin）,吉西他滨（Gemcitabine）,长春瑞滨（Vinorelbine）,紫杉醇（Paclitaxel）,畀环磷酰胺（Iphospamide）5种化疗药物针对肺癌细胞悬液进行药敏检测;应用免疫组化进行MRP,（多药耐药相关蛋白1）及TopoII（拓扑异构酶Ⅱ）表达的检测,并将其表达情况与对应的化疗耐药性进行相关分析。结果①MRP．、TopoⅡ在肺癌中总的阳性表达率分别为：72．5％、50．0％。鳞癌和腺癌MRP1、TopoⅡ相比的表达差异无统计学意义（P〉0．05）,但鳞癌或腺癌和小细胞肺癌在MRP1、TopoⅡ表达相比差异有统计学意义（P〈0．05）;②MRP,的表达与顺铂、吉西他滨、长春瑞滨的耐药性均呈显著的正相关（P〈0．05）,其表达与紫杉醇、异环磷酰胺的耐药性差异无统计学意义（P〉0．05）;TopoⅡ的表达与顺铂、吉西他滨、紫杉醇、异环磷酰胺的耐药性均呈显著的正相关（P〈0．05）,其表达与长春瑞滨的耐药性差异无统计学意义（P〉0．05）。结论①MRP1较高表达及TopoⅡ的较低表达共同介导参与了肺癌耐药的机制,且与检测的化疗药物有不同程度的相关性。②应用肿瘤细胞体外培养、进行体外药敏检测,并明确耐药基因的表达情况,对于识别可能的耐药个体,选择合理有效的化疗药物,可能将会最大限度地避免无效化疗和提高化疗疗效。     

积雪草酸通过抑制耐药相关蛋白表达增强U87MG胶质瘤细胞对紫杉醇 的敏感性

目的： 探索积雪草酸（asiatic acid,AA）对紫杉醇（paclitaxel, PTX）耐药性胶质瘤细胞的抑制作用及其可能的作用机 制。 方法： CCK-8实验、实时荧光定量PCR、Western blotting检测AA对成胶质细胞瘤U87MG细胞的增殖、凋亡的影响。浓度递 增法构建PTX耐药性细胞株PR-U87MG,以U87MG细胞为对照,CCK-8实验验证PR-U87MG细胞对PTX的耐药性,实时荧光定 量PCR、Western blotting检测PR-U87MG细胞中MDR1、LRP mRNA及蛋白的表达水平。AA和PTX单独或联合处理PR-U87MG 细胞,CCK-8实验、实时荧光定量PCR、Western blotting检测各组细胞增殖活力及凋亡的变化。 结果： 成功构建PTX耐药性细胞 株PR-U87MG。AA可以剂量依赖方式抑制U87MG细胞和PR-U87MG细胞的增殖活力（P<0.01）,并明显促进其凋亡（P<0.01）。 与AA或PTX单独处理组相比,联合处理组中PARP1的蛋白水平显著减少（P<0.01）,caspase 3的裂解量显著增加（P<0.01）,耐药 相关蛋白P-糖蛋白1 （P-dycoprotein 1, Pgp-1）和LRP表达水平显著减少（P<0.01）。 结论： AA可有效增强U87MG胶质瘤细胞株 对PTX的敏感性,其机制可能与AA抑制具有药物排出功能的耐药蛋白Pgp-1和LRP表达有关。     

Demethylzeylasteral (ZST93) inhibits cell growth and enhances cell chemosensitivity to gemcitabine in human pancreatic cancer cells via apoptotic and autophagic pathways

The overall 5‐year survival rate of patients with human pancreatic cancer remains less than 8% because of its aggressive growth, early metastasis and resistance to conventional chemoradiotherapy. It is essential to develop innovative and effective therapeutic agents to improve its prognosis. Demethylzeylasteral (ZST93) is a novel triterpenoid monomer extracted from the xylem of Tripterygium roots. Our study aimed to assess the effects of ZST93 on cell proliferation and its role in the chemosensitivity to gemcitabine in human pancreatic cancer cells. The effects of ZST93 on cancer cell proliferation, cell cycle distribution, apoptosis and autophagy were evaluated in various human pancreatic cancer cell lines, and the antitumor effects of ZST93 alone and in combination with gemcitabine were identified in a xenograft mouse model. The results showed that ZST93 could inhibit the proliferation of pancreatic cancer cells and arrest cell cycle at G0/G1 phase by regulating the expression of Cyclin D1 and Cyclin A2. Moreover, ZST93 killed pancreatic cancer cells through two different mechanisms: inducing autophagic cell death at low concentrations and apoptotic cell death at high concentrations. Furthermore, ZST93 could enhance the chemosensitivity of pancreatic cancer cells to gemcitabine both in vitro and in vivo through modulation of the cross talk between autophagy and apoptosis. ZST93 is a potential therapeutic agent for developing novel therapeutic strategies in human pancreatic cancer.