THERMALLY SENSITIVE DRUG DELIVERY SYSTEM FOR TUMORS

这项研究的总体目标是确定一种新的热敏脂质体递送系统的药物释放机制和药物作用机制，该系统在动物实验中已经显示出非常积极的局部控制。 建议继续进行关于温度触发的药物从新脂质体释放以及使用其他脂质和表面活性剂的基本体外研究，以更好地理解和控制该过程。 这些体外研究将与体内研究相结合，这些研究将确定药物递送、药物分布、药物作用和功效，所有这些都通过应用温和的、临床上可达到的高温来增强。 这些目标将通过实现以下具体目标来实现。 SA 1.为了更全面地表征热诱导脂质膜对一系列溶质的渗透性的机制。SA 2.测试其他双层相容化合物。SA 3.探讨阿霉素新制剂诱导肿瘤生长延迟的机制。SA 4.优化脂质体阿霉素在实体瘤中的递送。SA 5.在肿瘤生长延迟模型中临床前检测两种不同脂质体药物制剂的抗肿瘤作用。 SA 1和2中的方法将包括用于药物释放的分光光度和量热分析、用于双层结构的电子显微镜和用于表征脂质体的热性质的差示扫描量热法。 在体内研究中，纯合NCr无胸腺裸鼠（20 q 3g）将用于生长四种肿瘤系：FaDu（人鳞状癌）、SKOV 3（人卵巢癌）、LNCaP（人前列腺癌）和MCF 7（人乳腺癌）。SA 3、4和5的实验方法包括：皮瓣窗室荧光显微镜和皮下肿瘤用于药物沉积、分布和肿瘤生长延迟;组织提取和HPLC用于药物分析;以及组织学染色用于内皮细胞凋亡。 这种新的低温敏感的脂质体提供了一个机会，一个完整的范式转变，关于使用热疗临床。 它在低于或等于42 ℃的温度下有效工作，因此现在可以考虑将这项技术应用于潜在的可治愈的深部肿瘤，如卵巢癌和前列腺癌。 这些研究是必要的，以优化新的系统，以实现局部控制的一系列实体瘤的临床试验中的新的脂质体阿霉素在杜克大学的计划项目。 这项研究的结果将对新兴的与健康相关的药物输送领域，特别是癌症治疗至关重要。

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.