基因miRNA-34a靶向纳米复合物抗前列腺癌细胞增殖的作用研究

目的 通过构建具有前列腺癌细胞特异性靶向作用的基因载体适配体——聚乙二醇-聚酰胺-胺(APT-PEG-PAMAM),携带具有抗前列腺癌增殖作用的基因miRNA-34a,考察载体系统的转染效率及其对前列腺癌细胞的抑制作用。 方法 运用核磁共振(NMR)鉴定APT-PEG-PAMAM基因载体的结构;利用粒径电位仪对APT-PEG-PAMAM/miRNA纳米复合物进行表征;利用基因转染实验考察APT-PEG-PAMAM/miRNA纳米复合物在前列腺癌细胞(PC3和LNCaP)上的表达效果;利用CCK-8细胞增殖抑制实验考察APT-PEG-PAMAM/miRNA-34a对前列腺癌细胞的抑制作用。 结果 通过结构鉴定确定APT-PEG-PAMAM合成成功。定性、定量转染效率实验证明,经APT进一步修饰后,对LNCaP细胞转染效率显著增加,证明APT的靶向作用。CCK-8细胞增殖实验证明,APT-PEG-PAMAM/miRNA-34a对前列腺癌细胞具有抑制作用。 结论 APT-PEG-PAMAM/miRNA-34a有望成为今后靶向治疗前列腺癌的基因药物。     

姜黄中姜黄素类化合物抗前列腺癌及对15-脂氧合酶抑制活性的初步研究

摘 要 目的：研究姜黄中姜黄素类化合物对前列腺癌细胞PC3, DU145, LNCaP增殖及对15 脂氧合酶（15 LOX）抑制作用,并考察两者相关性。方法: 应用四甲基偶氮唑比色法（MTT）测定姜黄乙酸乙酯部位、总姜黄素、姜黄素、单去甲氧基姜黄素、双去甲氧基姜黄素对前列腺癌细胞PC3, DU145, LNCaP增殖抑制;应用脂氧合酶抑制药筛选试剂盒测定对15 LOX抑制活性,分析两者的相关性。结果: 姜黄素对15 LOX抑制活性最好,在6 μmol·L^-1时,姜黄素抑制率为63.1%,且其对前列腺癌细胞PC3, DU145, LNCaP抑制活性也较好,IC₅₀分别为(14.75±2.37), (18.99±3.43), (19.02±2.52) μmol·L^-1;天然姜黄素类化合对前列腺癌细胞增殖的抑制活性与对15 LOX抑制活性呈一定的相关性（P<0.05）。结论:天然姜黄素类化合物抗前列腺癌作用与对脂氧合酶的抑制作用具有一定相关性,脂氧合酶可能是天然姜黄素作用于前列腺癌的靶标之一。     

姜黄素上调前列腺癌细胞LNCaP中maspin基因的表达

目的研究姜黄素对前列腺癌细胞LNCaP凋亡的影响和对maspin基因表达的调控作用。方法利用不同浓度的姜黄素处理前列腺癌细胞LNCaP，MTT法和DNA 电泳检测不同时相LNCaP细胞的活性和凋亡情况，RT-PCR和Western blotting检测转录水平和翻译水平maspin基因的表达情况。将包含maspin 5′侧启动子区847 bp(-764～+83)DNA的荧光素酶表达载体pGL3-maspin瞬时转染LNCaP，姜黄素作用细胞48 h后，应用荧光素酶测定系统检测maspin启动子的表达活性作用。结果姜黄素抑制LNCaP细胞的生长活性，诱导LNCaP细胞的凋亡，增强LNCaP细胞中maspin基因的表达。结论姜黄素增强LNCaP细胞中maspin基因的表达是通过促进启动子的转录活性起作用的。     

磁共振高b值弥散加权成像在筛查前列腺癌中的应用价值探讨

目的 探讨磁共振高b值（b>1 000 s/mm²）弥散加权成像（DWI）在筛查前列腺癌的临床应用价值。方法 搜集2013年10月至2017年9月合肥市滨湖医院收治的前列腺病变患者32例，其中前列腺癌24例，前列腺炎或前列腺增生8例，术前均行磁共振不同b值DWI检查，最后通过穿刺或手术所得病理证实。比较分析前列癌患者前列腺内不同b值（800、3 000 s/mm²）癌性组织与非癌性组织弥散信号强度。结果 前列腺癌的癌性组织弥散信号强度高于非癌性组织的信号强度，对比度较大，差异有统计学意义（P<0.05）；高b值（3 000 s/mm²）较低b值（800 s/mm²）显示对比度更大，差异有统计学意义（P<0.05），并且对癌性组织的范围及与周围组织的关系显示更清晰。在前列腺癌的筛查中，低b值时敏感性为87.50%、特异性为75.00%、准确性为84.38%，高b值时敏感性为100.00%、特异性为87.50%、准确性为96.88%。结论 在前列腺癌的筛查中，磁共振高b值DWI较低b值更具有诊断价值。     

PC12细胞SLC6A4基因沉默稳转细胞系的建立及SLC6A4基因沉默对缺氧PC12细胞凋亡的影响

目的 构建SLC6A4基因RNA干扰（RNAi）-短发夹RNA（shRNA）慢病毒表达载体,建立慢病毒介导沉默SLC6A4基因的PC12细胞稳转细胞系,检测SLC6A4基因沉默对缺氧诱导的细胞凋亡的影响。方法 设计合成3条针对SLC6A4基因的shRNA干扰序列,构建于慢病毒载体质粒GV248中,在293T细胞中共转染进行慢病毒包装。转染大鼠肾上腺髓质嗜铬细胞瘤PC12细胞,荧光显微镜观察GFP荧光,筛选最佳shRNA干扰序列,应用嘌呤霉素筛选出稳定转染的细胞株。应用RT-PCR方法检测SLC6A4基因的表达,Western blot方法检测蛋白5-HTT的表达变化,流式细胞术检测沉默SLC6A4基因对缺氧诱导的PC12细胞凋亡的影响。结果 成功构建SLC6A4-shRNA慢病毒载体并转染PC12细胞,与正常对照组及干扰对照组比较,干扰组细胞内SLC6A4基因和蛋白表达明显降低（P<0.01）,证实慢病毒载体能够有效沉默SLC6A4基因,沉默SLC6A4基因可以逆转缺氧诱导的细胞凋亡。结论 通过shRNA慢病毒载体途径可有效沉默PC12细胞SLC6A4基因,沉默SLC6A4基因可以逆转缺氧诱导的细胞凋亡。     

pH响应纳米载药系统DOX@MIL-101(Fe)-NH2/HA的制备及靶向抗肿瘤作用研究

目的 制备透明质酸(hyaluronan acid，HA)修饰的纳米金属有机框架MIL-101(Fe)-NH₂载药系统，并进行体外抗肿瘤活性评价。方法 采用溶剂热法制备MIL-101(Fe)-NH₂，通过物理吸附法制备HA修饰载阿霉素的DOX@MIL-101(Fe)- NH₂/HA(DMNH)。并利用扫描电子显微镜、X射线衍射仪、氮气吸附-脱附法等对所合成材料及载药系统进行表征。采用透析法考察了载药系统的体外释药行为，并利用激光共聚焦显微镜观察HepG2细胞对其摄取情况。结果 MIL-101(Fe)-NH₂形貌为规则的正八面体，比表面积和粒径分别为1 061.45 m²·g^-1和200 nm。载药后DMNH的尺寸均一，比表面积为205.84 m²·g^-1，粒径为300 nm。MIL-101(Fe)-NH₂的最佳载药率为65.3%，根据药物释放曲线，从装有阿霉素的MIL-101(Fe)-NH₂载药体系(DMN)、DMNH中释放阿霉素显示出时间和pH依赖性。细胞摄取试验结果显示DMNH较其他组别可以运输更多的阿霉素进入HepG2细胞。细胞毒性的结果证实在相同的药物浓度下，DMNH表现出更高的肿瘤细胞杀伤效率。结论 本研究制备的DMNH载药系统结构稳定、载药量和释药效率高，同时具有优异的肿瘤细胞靶向性及pH响应释放特性，在抗肿瘤药物靶向传输方面具有应用前景。     

基于聚乙烯亚胺的还原响应型胶束提高反义寡核苷酸转染效率及其体内抗肿瘤作用研究

目的 在支化聚乙烯亚胺(polyethyleneimine,PEI)基础上,合成一种含有二硫键的聚合物PEI-ss-PEG₂₀₀₀-DSPE,并将其制备成阳离子胶束(P-ss-PD),在人乳腺癌细胞株中考察P-ss-PD胶束降低细胞毒性,提高反义寡核苷酸(Antisense oligonucleotides,ASO)转染效率的能力,并对P-ss-PD胶束在裸鼠体内的抗肿瘤效果进行研究。方法 以二硫键为连接臂,将PEG₂₀₀₀-DSPE接枝到支化PEI上合成PEI-ss-PEG₂₀₀₀-DSPE。采用乙醇注入法制备P-ss-PD胶束,与ASO结合后得到P-ss-PD/ASO纳米复合物。采用激光粒度分析仪测定不同质量比的P-ss-PD/ASO纳米复合物的粒径和zeta电位。采用琼脂糖凝胶阻滞试验考察P-ss-PD/ASO纳米复合物的结合度,确定最佳质量比;同时考察P-ss-PD胶束的还原响应能力。采用CCK8试剂盒检测P-ss-PD胶束的细胞毒性。使用流式细胞仪和高内涵细胞成像分析系统考察P-ss-PD胶束在MDA-MB-231细胞中的转染效率。建立MDA-MB-231荷瘤裸鼠模型,考察P-ss-PD胶束的抑瘤活性。结果 当质量比为300∶1时,P-ss-PD/ASO纳米复合物粒径最小且稳定性较好,平均粒径为(58.90±4.08)nm,平均zeta电位值为(16.80±1.23)mV,形态为均一的球形。P-ss-PD/ASO纳米复合物具有还原响应力,在高度还原性条件下能够释放装载的ASO。在体外细胞实验中,与未修饰的PEI相比,P-ss-PD胶束的细胞毒性显著降低,细胞转染效率显著提高。在体内动物实验中, P-ss-PD/ASO纳米复合物对荷瘤裸鼠的肿瘤生长抑制率>50%。结论 本研究制备的P-ss-PD胶束是一种低毒高效的非病毒载体,具有还原响应释放特性,在ASO药物递送方面具有应用前景。     

SP94修饰的肝靶向阳离子基因载体的制备及其体外评价

目的：研究适配体SP94修饰的阳离子基因载体H₃R₅,合成新型肝靶向纳米复合物SP94-H₃R₅/miR195,增加对肝癌细胞的靶向性,提高基因的转染效率。方法：经半胱氨酸修饰的SP94与H₃R₅末端的半胱氨酸发生氧化反应,组装得到SP94-H₃R₅,利用¹H-NMR鉴定SP94-H₃R₅载体的结构,通过电位粒度仪测定纳米复合物的电位和粒径,利用琼脂糖凝胶电泳考察载体对miR195的压缩能力。以体外培养的人肝癌SK-Hep-1为研究对象,CCK8法检测SP94-H₃R₅和H₃R₅对细胞增殖的抑制作用,采用激光共聚焦显微镜考察肝癌细胞对纳米复合物的摄取,以pEGFP为报告基因考察基因转染效率,Western blot 实验检测SK-Hep-1细胞VEGF的蛋白表达。结果：SP94-H₃R₅具有生物相容性,可以压缩miR195形成稳定的纳米复合物,SP94-H₃R₅/miR195与H₃R₅/miR195相比可以更多地被SK-Hep-1摄取（P<0.01）,SP94-H₃R₅转染效率高于非靶向载体H₃R₅,对VEGF的阻滞作用也更高（P<0.01）。结论：SP94-H₃R₅兼具纳米材料的被动靶向作用和适配体的主动靶向作用,有潜力成为肝癌治疗中的新型载体。     

一种用于实现脑靶向的负载长春新碱抗肿瘤纳米药物制剂的制备及表征

目的 制备合适尺寸的负载药物的纳米制剂,通过表面修饰,获取一种具有缓控释性的脑组织药物递送系统。方法 琥珀酸胆甾醇酯（CHS）与普鲁兰多糖经酯化反应形成疏水改性普鲁兰多糖（CHP）。CHP再通过透析法负载长春新碱（VCR）及通过乳化作用对聚山梨酯80（PS-80）进行表面修饰,得到VCR-CHP-PS纳米粒子。利用傅立叶红外光谱仪（FTIR）、核磁共振氢谱仪（¹H-NMR）对聚合物进行表征,动态光散射仪表征纳米粒子的粒径及电位。透射电镜观测CHP形态,并用等温滴定量热法测定载药纳米粒子VCR-CHP对PS-80的吸附特性。结果 FTIR和¹H-NMR证明CHS和CHP已成功合成。VCR-CHP-PS纳米粒子的平均粒径为414.2 nm,平均PDI为0.325,平均Zeta电位约为-19.5 mV。PS-80在CHP纳米粒子上的覆盖率为（149±43.5）%。VCR-CHP纳米粒子中VCR的载药量约为5.36%,包封率约为61.14%,72 h释放量约为61.43%。结论 疏水改性普鲁兰多糖纳米制剂具有较好的载药量和包封率及一定的缓释功能,有望成为脑靶向纳米药物载体。     

甘草次酸修饰马钱子碱纳米给药系统的体内外肝靶向性评价

目的 制备甘草次酸（GA）修饰的马钱子碱（B）-聚乙二醇-二硫代二丙酸-单硬脂酸甘油酯（PSG）纳米粒（NPs）（B-GPSG-NPs）并评价其体内外肝靶向性。方法 采用溶剂乳化超声法制备B-GPSG-NPs和B-PSG-NPs,于透射电镜下观察其外观形态,测定其粒径、多分散性指数（PDI）、Zeta电位、包封率、载药量等理化性质。建立检测心、肝、脾、肺、肾、脑组织中马钱子碱含量的高效液相色谱法。将雌雄各半的小鼠90只随机分为3组：马钱子碱组、B-PSG-NPs组、B-GPSG-NPs组,禁食不禁水12h后,尾iv相应溶液（以马钱子碱计10mg·kg^-1）,分别于给药后10、30、60、120、180min取各组织进行HPLC检测,计算相对摄取率（Re）和靶向效率（Te）,以评价给药系统的体内靶向性。制备载异硫氰基荧光素（FITC）的FITC-B-PSG-NPs、FITC-B-GPSG-NPs,FITC、空白PSG载体制成的纳米粒（PSG-NPs）、空白GPSG载体制成的纳米粒（GPSG-NPs）以及含马钱子碱质量浓度分别为500、250、125μg·mL^-1的FITC-B-PSG-NPs和FITC-B-GPSG-NPs与CBRH-7919肝癌细胞共培养24h,荧光显微镜下观察CBRH-7919细胞对各受试物的摄取情况,以评价给药系统的体外靶向性。结果 B-GPSG-NPs的粒径为（98.91±3.62）nm,呈正态分布;PDI值为（0.221±0.006）,Zeta电位为-（19.63±0.40）mV,包封率为（78.37±1.83）%,载药量为（2.86±0.05）%;B-PSG-NPs与B-GPSG-NPs组肝脏的Re分别为1.49和1.72,明显高于其他组织;马钱子碱组肾脏Te最高,脑Te最低,而B-PSG-NPs和B-GPSG-NPs组肝脏中马钱子碱的Te明显高于其他各组织;CBRH-7919细胞摄取B-GPSG-NPs效率明显高于B-PSG-NPs,并表现出剂量相关性。结论 制备的BGPSG-NPs在体内外均表现出良好的肝靶向效应,且优于无GA修饰的B-PSG-NPs。     

Octreotide-conjugated PAMAM for targeted delivery to somatostatin receptors over-expressed tumor cells

Abstract

Purpose: An octreotide-conjugated polyamidoamine (PAMAM) dendrimer was synthesized and employed as nanocarriers of methotrexate (MTX), for targeting to the somatostatin receptors over-expressed tumor cells.

Methods: PAMAM–PEG–octreotide (PPO) and PAMAM–PEG (PPG) were synthesized and characterized. The cellular uptake of fluorescein isothiocyanate (FITC)-labeled PPO (PPO-FITC) and PPG (PPG-FITC) were investigated. The cytotoxicity of MTX and MTX nanoparticles were conducted in the MCF-7 cells. Besides, the pharmacokinetics studies on MTX nanoparticles were carried out in rats.

Results: The structure of PPO was verified by NMR detection and the diameter was 11.05?±?1.80?nm, with the amount of MTX encapsulated by PPO was 30?(molecule/molecule). MTX nanoparticles possessed significantly higher cytotoxicity against MCF-7 cells compared with free MTX, especially the PPO/MTX nanoparticles. Correspondingly, the PPO-FITC carrier had higher cellular uptake efficiency compared to PPG-FITC. In addition, pharmacokinetics studies showed that PPO/MTX nanoparticles increased mean residence time and bioavailability of MTX distinctly.

Discussion and conclusion: With further cellular uptake test of FITC-labeled carriers, the enhanced cytotoxicity of PPO/MTX nanoparticles was reasonable to ascribe to the specific receptor-mediated endocytosis induced by octreotide. The present study suggests that this PAMAM–PEG–octreotide nanocarrier opens a new path for treating cancer with higher efficacy.     

Thioaptamer-conjugated CD44-targeted delivery system for the treatment of breast cancer in vitro and in vivo

The high transfection efficiency and enhanced therapeutic effect of drug delivery systems developed in recent years imply that ligand-decorated nanocarriers are potentially targeted vectors for breast cancer treatment. Thioaptamer (TA)-modified nanoparticles (NPs) designed in this study mainly consisted of ligand TA and dendritic polyamidoamine (PAMAM). Knowing that TA can bind to CD44-receptors in breast cancer, this study was intended to validate the safety and feasibility of systemic miRNA delivery to breast cancer cells by TA-PEG-PAMAM/miRNA (polyethylene glycol – PEG), testify its tumor targeting efficiency in vitro, and observe its biodistribution when it was administered systemically to a xenograft mouse model of breast cancer. The in vivo and ex vivo imaging results in human breast cancer tumor-bearing mice showed that TA-modification was able to enhance the accumulation of NPs in the breast cancer tumor. Our data showed that TA-NPs did not induce functional impairment to normal tissues and vital organs. TA-NPs may prove to be a safe and effective miRNA deliver system for breast cancer treatment, and could be widely used in pre-clinical and eventually clinical arenas of breast cancer treatment.     

Efficient delivery of micro RNA to bone-metastatic prostate tumors by using aptamer-conjugated atelocollagen in vitro and in vivo

Bone is the primary site of skeletal metastasis in prostate cancer (PCa). Atelocollagen (ATE)-mediated siRNA delivery system can be used to silence endogenous genes involved in PCa metastatic tumor cell growth. However, we hope that the delivery system can target PCa cells to reduce damage to the bone tissue and improve the therapeutic effect. RNA aptamer (APT) A10-3.2 has been used as a ligand to target PCa cells that express prostate-specific membrane antigen (PSMA). APT was investigated as a PSMA-targeting ligand in the design of an ATE-based microRNA (miRNA; miR-15a and miR-16-1) vector to PCa bone metastasis. To observe the targeted delivery and transfection efficiency of ATE–APT in PSMA-overexpressing cells, luciferase activity and biodistribution of nanoparticles in Balb/c mice was analyzed. The anticancer effect of nanoparticles in vivo was investigated using the survival times of human PCa bone metastasis mice model. Luciferase assays of pGL-3 expression against PC3 (PSMA^?) and LNCaP (PSMA⁺) cells showed that the transfection efficiency of the synthesized DNA/ATE–APT complex was higher than that of the DNA/ATE complex. The anticancer efficacy of miRNA/ATE–APT was superior to those of other treatments in vivo. This PSMA-targeted system may prove useful in widening the therapeutic window and allow for selective killing of PCa cells in bone metastatic foci.     

Biological evaluation of RGDfK-gold nanorod conjugates for prostate cancer treatment

Selective delivery of gold nanorods (GNRs) to sites of prostate tumor angiogenesis is potentially advantageous for localized photothermal therapy. Here, we report the cellular uptake and biodistribution of GNRs surface functionalized with the cyclic RGDfK peptide. The GNRs were synthesized to have a surface plasmon resonance (SPR) peak at 800?nm and grafted with a thiolated poly(ethylene glycol) (PEG) corona with or without RGDfK. The binding and uptake of the targeted (RGDfK) and untargeted GNRs were evaluated in DU145 prostate cancer and human umbilical vein endothelial cells (HUVEC) by high-resolution dark field microscopy, inductively coupled plasma mass spectrometry (ICP-MS), and transmission electron microscopy (TEM). The biodistribution of both GNRs was then evaluated in prostate tumor bearing mice. Targeting of the RGDfK surface-modified GNRs was confirmed in vitro due to selective binding and uptake by endothelial cells. Tumor targeting was not observed in vivo, however, due to fast clearance of the RGDfK-GNRs from the blood. Further modifications of the nanoparticle’s surface properties are needed to enhance localization of the targetable system in sites of tumor angiogenesis.     

Which one performs better for targeted lung cancer combination therapy: pre- or post-bombesin-decorated nanostructured lipid carriers?

Abstract

Purpose: The co-delivery of gene and drugs has the potential to treat cancer. The aim of this study was to compare post-bombesin decorated nanostructured lipid carriers (NLC) carrying both doxorubicin (DOX) and DNA with pre-bombesin decorated NLC for lung cancer therapy.

Methods: Post-bombesin decorated NLC were prepared by two steps. First, DOX and DNA-loaded NLC (DOX-DNA-NLC) was prepared. Second, Bombesin-NH₂ (BN-NH₂) was added into DOX-DNA-NLC to react with stearic acid-polyethylene glycol-COOH (SA-PEG-COOH) loaded in NLC. Pre-bombesin decorated NLC were prepared by two steps. First, Bombesin (BN)-conjugated ligands were synthesized. Second, DOX and DNA were loaded into BN decorated NLC. Their average size, zeta potential, drug and gene loading were evaluated. NCl-H460 human non-small lung cancer cells (NCl-H460 cells) were used for the testing of in vitro transfection efficiency and in vitro cytotoxicity. In vivo transfection efficiency and anti-tumor effect of NLC were evaluated on mice bearing NCl-H460 cells model.

Results: Post-bombesin decorated NLC has a particle size of 128?nm, DOX encapsulation efficiency (EE) of 85% and DNA EE of 91%. Pre-bombesin decorated NLC has a particle size of 101?nm, DOX EE of 86% and DNA EE of 92%. Post-bombesin decorated NLC displayed more stable and remarkably higher transfection efficiency and better anti-tumor ability than pre-bombesin decorated NLC both in vitro and in vivo.

Conclusion: Post-bombesin decorated NLC could function as better carriers to improve the cell targeting and nuclear targeting ability. The resulting nanomedicine could be a promising active targeting drug/gene therapeutic system for lung cancer therapy.     

Synthesis,molecular modeling,in vivo study,and anticancer activity of 1,2,4‐triazole containing hydrazide–hydrazones derived from (S)‐naproxen

A new series of 1,2,4‐triazole containing hydrazide–hydrazones derived from (S)‐naproxen ( 7a–m ) was synthesized in this study. The structures of these compounds were characterized by spectral (Fourier‐transform infrared spectroscopy, ¹H‐nuclear magnetic resonance (NMR), ¹³C‐NMR, and high‐resolution electron ionization mass spectrometry) methods. Furthermore, molecular modeling of these compounds was studied on human methionine aminopeptidase‐2. All synthesized compounds were screened for anticancer activity against three prostate cancer cell lines (PC3, DU‐145, and LNCaP) using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium colorimetric method. Compound 7a showed the best activity against the PC3, DU‐145 and LNCaP cancer cell lines with IC₅₀ values of 26.0, 34.5, and 48.8 μM, respectively. Compounds 7b , 7k , and 7m showed anticancer activity against cancer cell lines PC3 and DU‐145 with IC₅₀ values of 43.0, 36.5, 29.3 μM and 49.8, 49.1, 31.6 μM, respectively. Compounds 7f and 7g showed anticancer activity against PC3 cells with IC₅₀ values of 43.4 and 34.5 μM, respectively. To assess the biodistribution in mice of IRDye800, dye‐labeled compound 7a or 100 μM of free dye was injected intravenously into the mice's tail. In vivo images were taken with in vivo imaging system spectrum device at 60, 120, 180, 240, 300, and 360 min after injection. At the end of 360 min, ex vivo studies were carried out to determine in which organs the dye was accumulated in the urogenital system. Ex vivo studies showed that the accumulation of compound 7a in the prostate is greater than that of the free dye, and it is concluded that compound 7a may be promising for the treatment of prostate cancer.     

Cyclic RGD-poly(ethylene glycol)-polyethyleneimine is more suitable for glioblastoma targeting gene transfer in vivo

Arginine-glycine-aspartic acid (RGD) is a widely chosen ligand to improve the specific gene targeting transfection efficiency of polyethyleneimine (PEI) in vivo. However, the optimal RGD conjugating mode, RGD-poly(ethylene glycol)-PEI (RGD-PEG-PEI) or RGD-PEI-methoxyl poly(ethylene glycol) (RGD-PEI-mPEG) still remains controversial. In this study, RGD-PEG-PEI and RGD-PEI-mPEG were synthesized and compared with respects to their glioblastoma cell-binding capability and tumor-targeting ability of their complexes with plasmid DNA. These results demonstrated that RGD-PEG-PEI/plasmid enhanced green fluorescent protein (pEGFP)-N2 complexes had higher binding affinities with U87 cells than RGD-PEI-mPEG/pEGFP-N2 complexes. The gene transfection was also performed on U87 cells in vitro and in vivo. In vitro, both of the RGD-modified PEI derivatives enhanced the gene transfection efficiency to some extent. However, all of the complexes (with or without RGD modification) had high transfection efficiency. The biodistribution of RGD-PEG-PEI/pEGFP-N2 complexes in mice bearing subcutaneous glioblastomas were significantly greater than that of RGD-PEI-mPEG/pEGFP-N2 complexes, suggesting a more efficient gene transfection in vivo. In the RGD-PEG-PEI, the use of a PEG spacer was particularly important. These results indicated that RGD-PEG-PEI was more suitable for targeted gene transfer in vivo.     

Exploration of effects of emodin in selected cancer cell lines: enhanced growth inhibition by ascorbic acid and regulation of LRP1 and AR under hypoxia‐like conditions

This study explores the link between the antiproliferative activity of emodin through the generation of reactive oxygen species (ROS) in various cancer cell lines and the expression of the androgen receptor (AR) in the prostate cancer cell lines LNCaP (androgen‐sensitive) and PC‐3 (androgen‐refractory), as well as the pro‐metastatic low‐density lipoprotein receptor‐related protein 1 (LRP1) in the above prostate cancer cells and the nonprostate cell lines A549 (lung), HCT‐15 (colon) and MG‐63 (bone) under normoxic and hypoxia‐like conditions. Among all cell lines, emodin showed most growth inhibition in LNCaP, followed by A549. The mechanism of cytotoxicity of emodin was postulated to be the widely reported ROS generation, based on the observations of poor in vitro radical‐scavenging activity and increased growth inhibition of emodin by ascorbic acid (AA) pre‐treatment owing to the additive effects of ROS generation by emodin and pro‐oxidant effects of AA. Emodin downregulated AR in LNCaP under normoxic and hypoxia‐like conditions (simulated by CoCl₂) and LRP1 under normoxia. Emodin upregulated LRP1 in other cell lines, except HCT‐15, under normoxic, and even more markedly under hypoxia‐like conditions. The downregulation of AR in LNCaP and upregulation of LRP1 in all cell lines, except HCT‐15, under hypoxia‐like conditions along with growth inhibition by emodin, suggests that emodin may be a useful therapeutic option against androgen‐sensitive prostate cancer and other such LRP1‐expressing cancers to attempt the targeting of the elevated LRP1 levels to allow the uptake of emodin and/or any other accompanying therapeutic agents by LRP1. Copyright © 2012 John Wiley & Sons, Ltd.