Antiproliferative effects of free and liposome-encapsulated retinoic acid in a squamous carcinoma model: monolayer cells and multicellular tumor spheroids

Summary Antiproliferative effects of free retinoic acid (RA) and liposome-encapsulated RA (RAlp) were compared in a squamous carcinoma system using both monolayer cells and multicellular tumor spheroids (MTS), an in-vivo-like model with three-dimensional histological structure. Initial studies examined the effect of lipid composition on the efficiency of RA encapsulation and on the subsequent toxicity of RAlp to red blood cells. In 5-day growth assays for monolayer cells, RA and RAlp (1 M-0.1 nM) produced similar growth inhibition. In 6-day growth assays for MTS, RAlp was shown to have increased effectiveness. Liposomal uptake by the squamous carcinoma cells was examined by culturing monolayers and MTS with fluorescence-tagged liposomes and examining them under fluorescence microscopy between days 1 and 6. Phagocytosed liposomes were present, but their low levels suggested that other mechanisms of drug delivery such as adsorption, fusion or direct lipid transfer probably occurred for RAlp. Histological examination of MTS showed that RA and RAlp produced similar alterations. In this squamous carcinoma system, liposomes are effective in delivering retinoic acid and in producing biological effects in monolayer cells and within the three-dimensional structure of MTS.Abbreviations MTS multicellular tumor spheroids - SCC squamous cell carcinoma - RA free -all-trans-retinoic acid - RAlp lipo-some-encapsulated RA - PtdCho dimyristoylglycerophosphocholine - PtdGro dimyristoylglycerophosphoglycerol This work was supported in part by M. D. Anderson Annual Campaign Funds and by United States Public Health Service grants CA38751 and CA57166 from the National Cancer InstitutePresent address: Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York; NY 10021, USA     

超声联合微泡增强脂质体介导基因转染RPE细胞的实验研究

目的 比较声诺维联合超声与脂质体法介导基因转染RPE细胞的转染率和安全性,探讨超声联合微泡增强脂质体转染率的可行性.方法 RPE细胞培养在24孔板,质粒用量2 μg/孔,分为对照组、超声辐照组、超声联合微泡组(包括2 W/cm2和3 W/cm2两个亚组)、脂质体组、脂质体+超声+微泡组5组,每组10孔细胞.荧光显微镜观察基因转染情况,流式细胞仪检测基因转染率,Annexin Ⅴ-FITC和PI双染流式细胞法检测凋亡率.结果 单纯超声辐照组基因转染率为(1.06±0.13)%,超声联合微泡组分别为(15.81±1.70)%和(20.86±2.63)%,脂质体组为(30.06±3.49)%,明显高于超声联合微泡组(P<0.05).脂质体+超声+微泡组为(44.51±1.28)%,明显高于脂质体组(P<0.05).结论 脂质体介导EGFP转染RPE细胞的效率高于超声联合微泡的转染率.超声联合微泡能明显提高脂质体的转染率.     

脂质体携载前列腺素E_1抑制血小板功能降低心肌梗死面积

目的　在家兔心肌缺血 再灌注模型上观察脂质体携载前列腺素E1(Lipo PGE1)对血小板功能的抑制作用和对缺血心肌的保护作用。方法　 2 0只家兔随机分成Lipo PGE1治疗组及对照组 ,每组 10只。两组家兔左冠状动脉前降支结扎 4 0min后松开 ,再灌注 2h。于再灌注前 10min分别自耳缘静脉注射Lipo PGE1( 2 μg/kgPGE1)及等容量的脂肪乳剂 (Lipo PGE1的溶剂 )。整个实验过程中连续记录血压及心电变化。家兔处死后以Evans蓝及氯化三苯基四氮唑 (TTC)双重染色确定缺血及梗死心肌范围 ,心肌梗死范围以梗死心肌占危险区心肌重量百分比 (MI/RISK)表示。通过测定血浆血栓素B2 (TXB2 )及α颗粒膜蛋白 14 0 (GMP 14 0 )含量反映周围血小板活性状态。结果　再灌注前静脉应用 2 μg/kgLipo PGE1能减少家兔再灌注期心律失常的发生 ,不产生明显的血流动力学障碍。Lipo PGE1治疗组心肌梗死范围 ( 3 3 .6± 5 .5 ) %较对照组 ( 4 3 .8± 5 .1) %显著缩小 (P <0 .0 1)。Lipo PGE1治疗组再灌注期血浆TXB2 及GMP 14 0含量较对照组明显降低 (P <0 .0 5及P <0 .0 1) ,血小板最大聚集率较对照组也明显降低 (P <0 .0 1)。结论　Lipo PGE1能显著抑制血小板聚集、活化 ,挽救缺血心肌 ,缩小心肌梗死范围。     

高效液相色谱法测定氢醌脂质体的氢醌含量与包封率

目的为减轻氢醌的刺激性和毒性,增加药物在表皮内的浓度和滞留时间,制备氢醌脂质体并了解其氢醌含量与包封率。方法采用旋转蒸发超声法制备氢醌脂质体,高效液相色谱(HPLC)法检测氢醌脂质体含量及包封率。结果色谱条件下氢醌脂质体与辅料及溶剂峰分离良好,且线性关系良好。3组氢醌脂质体包封率分别为80.2%、85.2%、81.7%。结论氢醌脂质体质量控制方法简单、可靠、准确。     

低功率射频联合长春瑞滨长循环热敏脂质体抗肿瘤疗效的实验研究

目的 探讨低功率射频联合长春瑞滨长循环热敏脂质体对兔VX2肿瘤的抑瘤效果.方法 应用超声引导下组织块包埋法建立新西兰大白兔股部肌肉内VX2肿瘤模型.待肿瘤生长至0.8～1.0 cm时,根据肿瘤大小按区组随机的方法 将24只荷瘤兔分成4组.对照组(CON):静脉注射等量生理盐水;单纯射频组(RF):给予1 W 30 min射频治疗;长春瑞滨长循环热敏脂质体组(LCTSL):给予1.8 mg/kg长春瑞滨长循环热敏脂质体;长春瑞滨长循环热敏脂质体联合射频组(LCTSL+RF):射频作用(1 W 30 min)前给予1.8 mg/kg长春瑞滨长循环热敏脂质体.治疗分别在第1、4、7天,共3次.治疗前及治疗后超声连续观测肿瘤的大小,治疗结束后8 d,处死实验兔测量肿瘤重量,计算抑瘤率,标本进行病理检查.结果 所有实验兔均能耐受治疗完成实验.LCTSL+RF组抑瘤率为87.2%,显著高于RF和LCTSL组,差异有统计学意义(P<0.05);单纯射频作用无明显抑瘤效果.病理检查显示单纯射频作用无明显肿瘤坏死,而长春瑞滨长循环热敏脂质体联合射频可见明显的肿瘤细胞损伤及坏死.结论 低功率射频联合长春瑞滨热长循环热敏脂质体对兔VX2肿瘤有明显的抑瘤效果;射频消融联合长春瑞滨长循环热敏脂质体可能会增大消融范围,提高抗肿瘤疗效.     

转铁蛋白SA阳离子脂质体的合成

目的　制备转铁蛋白ＳＡ 阳离子脂质体,并检测其特性。方法　以Ｎ－ 羟琥珀酰亚胺３（２吡啶二硫代） 丙酸脂ＳＰＤＰ 为交联剂,连接转铁蛋白与ＳＡ 阳离子脂质体,并用受体放射分析法检测转铁蛋白ＳＡ 阳离子脂质体上转铁蛋白的活性。结果　ＨＴｆ（Ｆｅ）２ 与ＳＡ 阳离子脂质体的交联率为７６－５ ％ 。转铁蛋白ＳＡ 阳离子脂质体具有较高的携带ＤＮＡ的能力;转铁蛋白被连接到ＳＡ 阳离子脂质体上后其活性无明显改变。结论　以Ｎ羟琥珀酰亚胺３（２吡啶二硫代） 丙酸脂ＳＰＤＰ 为交联剂制备转铁蛋白ＳＡ 阳离子脂质体是一种连接效率高,能较好的保持转铁蛋白活性的好方法     

口服阿苯达唑脂质体大鼠体内药物动力学的研究

通过Wistar大鼠口服阿苯达唑脂质体的体内药物动力学实验,建立和考察了高效液相色谱法（HPLC）测定生物样品中阿苯达唑及其代谢产物的浓度的方法;用药动学软件包进行体内模型拟合,获取药动学参数和比较阿苯在唑脂质体的相对生物利用度。结果显示;测定阿苯达唑及其代谢产物的HPLC方法回收率较高,可满足汪同生物样品的测定;口服阿苯达唑脂质符合一级吸收二室动力学模型。与阿苯达唑片剂粉末相比,具有较高有生物利用度并有一定的肝脏靶向性。     

Liposome-based multifunctional nanoplatform as effective therapeutics for the treatment of retinoblastoma

Photothermal therapy has the characteristics of minimal invasiveness, controllability, high efficiency, and strong specificity, which can effectively make up for the toxic side effects and tumor resistance caused by traditional drug treatment. However, due to the limited tissue penetration of infrared light, it is difficult to promote and apply in clinical practice. The eye is the only transparent tissue in human, and infrared light can easily penetrate the eye tissue, so it is expected that photothermal therapy can be used to treat fundus diseases. Here in, a new nano-platform assembled by liposome and indocyanine green (ICG) was used to treat retinoblastoma. ICG was assembled in liposomes to overcome some problems of ICG itself. For example, ICG is easily quenched, self-aggregating and instability. Moreover, liposomes can prevent free ICG from being cleared through the systemic circulation. The construction of the nano-platform not only ensured the stability of ICG in vivo, but also realized imaging-guide photothermal therapy, which created a new strategy for the treatment of retinoblastoma.