Rigid-rod Peptides as Nanocarriers for Delivery of Cancer Drugs

描述(申请人提供)：癌症是美国第二大死因。在提高患者存活率方面，仅次于手术和放射治疗，化疗和药物联合治疗是最成功的。紫杉醇(PTX)是目前临床应用最成功的紫杉醇之一。PTX非常有效 用于治疗多种癌症，包括卵巢癌、乳腺癌、结肠癌、头颈部癌和非小细胞肺癌。不幸的是，目前使用的旨在增加PTX的溶解度和生物利用度的制剂与不良过敏反应有关。因此 合成和测试了几种前药，通常含有与多羧酸、糖、聚合物和多肽等亲水性和水解性基团相连的PTX。尽管有这些努力，但人们对开发新型前药用于靶向给药PTX和其他弱可溶性药物以提高其治疗效率有相当大的兴趣。该方案的目标是开发一类新型的用于低溶解度药物(如PTX)的局部给药系统(纳米载体)，该系统基于组装成三螺旋多肽(THP)的胶原蛋白模拟肽。PTX与THP的偶联与目前使用的前药相比具有许多潜在的优点：(1)它改善了前药的溶解性，(2)由于刚性棒状构象，它增加了对蛋白酶的抵抗力(3)它允许药物靶向序列或细胞穿透载体的掺入，(4)它允许将前药固定在 胶原蛋白基质。此外，与金属纳米载体不同，THP纳米载体可生物降解为生物安全的产品。该方案旨在开发基于PTX的多肽序列，以C2‘-OH位上的丁二酸键将PTX连接到多肽的赖氨酸基团上，形成水溶性模型前药。通过改变多肽的长度和序列，可以调节前药的溶解度。建议的多肽序列将形成THP刚性棒状纳米载体，提供更高的稳定性，防止体内生物降解。此外，THP载体将开启从亲水性胶原基质中输送疏水药物的可能性。前药的释放曲线将作为纳米载体结构的函数进行测量。通过合成不同长度的THP，并在胶原基质中加入预热(自组装)或非预热(共混)的纳米载体，我们希望能有效地控制前药的释放速度。将细胞穿透载体引入前药的可行性将被研究。还建议将多聚精氨酸序列掺入前药序列以研究纳米载体细胞的优先摄取。建议的紫杉醇前药的细胞毒性也将被研究。发展的目标是让国际和平研究所更多地参与与人类健康直接相关的跨学科研究，并提高国际和平研究所的生产力。所要求的支助将导致在国际和平研究所的实验室开发新的方法和协议，并增加研究生和本科生的参与，包括来自传统上代表人数不足的背景的学生。如果授予这种SC-3资助，将增加PI的研究产出，并提高主要赠款支持的竞争力，如NSF和NIH-RO1类型的拨款。

DESCRIPTION (provided by applicant): Cancer is the second leading cause of death in the United States. Next to surgery and radiation treatments, chemotherapy and combination therapies involving drugs are among the most successful in increasing patient survival rates. Paclitaxel (PTX) is one of the most successful taxoids in clinical use today. PTX is very effective in treatment of several cancers including: ovarian, breast, colon, head and neck, and non small cell lung cancer. Unfortunately, the currently used formulations which are intended to increase the solubility and thus bioavailability of PTX, are linked to adverse allergic reactions. Therefore several prodrugs, typically containing PTX conjugated with the hydrophilic and hydrolyzable groups such as polycarboxylic acids, sugars, polymers and peptides, were synthesized and tested. Despite these efforts there is a considerable interest in developing novel prodrugs for targeted drug delivery of PTX and other weakly soluble drugs to increase their therapeutic efficiency. The goal of this proposal is to develop a novel class of local drug delivery systems (nanocarriers) for low solubility drugs (such as PTX) based on collagen mimetic peptides assembled into triple helical peptide (THP) The conjugation of PTX with THP affords numerous potential advantages over currently used prodrugs: (1) it improves prodrug solubility, (2) it increases protease resistance due to rigid rod conformation (3) it allows incorporation of drug targeting sequence or cell penetrating vector, (4) it allows immobilization of the prodrug within a collagen matrix . Additionally, the THP nanocarrier unlike metallic nanocarriers biodegrades to biologically safe products. The proposal aims at developing peptide sequences to form water soluble model prodrugs based on PTX attached to the peptide's lysine group via succinylic link at C2'-OH position. By varying the peptide length and sequence the solubility of the prodrug will be adjusted. The proposed peptide sequences will form THP rigid-rod nanocarrier providing increased stability against in vivo biodegradation. Moreover, the THP carrier will open the possibility of delivering the hydrophobic drugs from hydrophilic collagen matrix. The release profile of a prodrug will be measured as a function of the nanocarrier structure. By synthesizing different length of THP and incorporating pre-heated (self-assembled) or non-preheated (blended) nanocarrier within collagen matrix we hope to effectively control the rates of the prodrug release. The feasibility of incorporating the cell-penetrating vectors into the prodrug wil be investigated. The incorporation of the polyarginine sequences into the prodrug sequence to study preferential nanocarrier cell uptake is also proposed. The cytotoxicity of the proposed Paclitaxel prodrug will also be studied. The developmental objective is to increase the PI's involvement in interdisciplinary research directly related to human health and to increase the productivity of the PI laboratory. The requested support will result in the development of new methodologies and protocols in the PI's laboratory and increased participation of graduate and undergraduate students, including students from traditionally underrepresented backgrounds. This SC-3 support, if awarded, will increase the PI's research output and improve competitiveness for major grant support such as NSF and NIH-RO1 type grants.