THERMALLY SENSITIVE DRUG DELIVERY SYSTEM FOR TUMORS

这项研究计划的总体目标是确定一种新的热敏型脂质体给药系统的药物释放机制和药物作用机制，该系统已经在动物实验中显示出非常积极的局部控制。建议继续进行有关温度触发药物从新脂质体释放以及使用其他脂类和表面活性物质的基础体外研究，以更好地了解和控制这一过程。这些体外研究将与体内研究相结合，这些研究将确定药物的传递、药物分布、药物作用和疗效，所有这些都将通过应用温和的、临床上可以达到的热疗而得到加强。这些目标将通过实现以下具体目标来实现。SA1.以更全面地描述热诱导的脂膜对一系列溶质的通透性的机制。SA2.以测试其他双层相容化合物。SA3.探讨阿霉素新剂型延缓肿瘤生长的机制。SA4.目的优化阿霉素脂质体在实体瘤中的给药效果。SA5.目的：在肿瘤生长延迟模型中，对两种不同脂质体制剂的抗肿瘤作用进行临床前研究。SAS1和2中的方法将包括药物释放的分光光度和量热分析，双层结构的电子显微镜，以及表征脂质体热性质的差示扫描量热法。在体内研究中，纯合子NCR裸鼠(20Q 3G)将被用来生长四种肿瘤株：人鳞癌FaDu、人卵巢癌SKOV3、人前列腺癌LNCaP和人乳腺癌MCF7。SAS3、4和5的实验方法包括用荧光显微镜观察皮瓣窗腔和皮下肿瘤的药物沉积、分布和肿瘤生长延迟；组织提取和高效液相色谱法进行药物分析；组织学染色检测内皮细胞的凋亡。这种新的低温敏感脂质体为热疗在临床上的应用提供了一个彻底的范式转变的机会。它在低于或等于42摄氏度的条件下有效工作，因此现在可以考虑将这项技术应用于潜在的可治愈的深层肿瘤，如卵巢癌和前列腺癌。这些研究是必要的，以便在杜克大学计划项目的新脂质体阿霉素的临床试验中，优化新系统，实现对一系列实体肿瘤的局部控制。这项研究的结果将对蓬勃发展的与健康相关的药物输送领域，特别是对癌症治疗至关重要。

The overall objective of this research proposal is to determine mechanisms of drug release and mechanisms of drug action for a new thermal-sensitive liposomal delivery system that has already shown very positive local control in animal experiments. It is proposed to continue basic in vitro studies concerning temperature-triggered drug release from the new liposomes and the use of other lipids and surfactants to provide greater understanding and control over the process. These in vitro studies will be coupled with in vivo studies that will determine drug delivery, drug distributions, drug action and efficacy, all enhanced by the application of mild, clinically attainable hyperthermia. These goals will be accomplished by carrying out the following specific aims. SA1. To more fully characterize the mechanism of thermally-induced lipid membrane permeability to a range of solutes. SA2. To test other bilayer compatible compounds. SA3. To investigate mechanisms of tumor growth delay induced by the new doxorubicin formulation. SA4. To optimize liposomal doxorubicin delivery in solid tumors. SA5. To test preclinically the antitumor effect of two different liposomal drug formulations in tumor growth delay models. Methods in SAs 1, and 2 will include spectrophotometric and calorimetric analysis for drug release, electron microscopy for bilayer structure, and differential scanning calorimetry for characterizing the thermal properties of the liposomes. In the in vivo studies Homozygous NCr athymic nude mice (20 q 3g) will be used to grow four tumor lines: FaDu, a human squamous carcinoma, SKOV3, a human ovarian carcinoma, LNCaP, a human prostate carcinoma, and MCF7, a human mammary carcinoma. Experimental methods for SAs 3, 4 and 5, include, skin flap window chamber with fluorescence microscopy and subcutaneous tumors for drug deposition, distribution and tumor growth delay; tissue extraction and HPLC for drug analysis; and histological staining for apoptosis of endothelial cells. This new low temperature sensitive liposome provides an opportunity for a complete paradigm shift with regard to the use of hyperthermia clinically. It works effectively at less than or equal to 42 C, and so applications of this technology can now be considered for potentially curable deep-seated tumors, such as ovarian and prostate cancer. The studies are necessary in order to optimize the new system to achieve local control for a range of solid tumors in clinical trials of the new liposomal doxorubicin in a Program Project at Duke University. The results of the study will be critical to the burgeoning health-related field of drug delivery, and to cancer treatment in particular.