Peritumorally transformable nanoparticles for intraperitoneal chemotherapy of ova

描述（由申请人提供）：从理论上讲，腹腔注射抗癌药物是上皮性卵巢癌的一种强有力的治疗选择。然而，由于药物在腹膜内停留时间短、潜在的泛腹膜毒性以及抗癌药物在细胞内摄取/积累不足等原因，IP化疗的困难阻碍了理论优势向临床益处的转化。我们建议开发一种新型的聚合物纳米颗粒（NPs）来克服这些问题。我们研究的长期目标是开发一种肿瘤特异性的抗癌药物纳米载体，用于安全有效的卵巢癌IP化疗。本研究的目的是创建聚乳酸-共乙醇酸（PLGA） NPs作为紫杉醇的载体，其在正常组织中是惰性的，但在肿瘤周围区域转化为活性形式（肿瘤周围可转化NPs或PTNPs）。这将允许NPs与非癌组织有最小的相互作用，但很容易被吸收并积聚在卵巢肿瘤细胞中，提供细胞内药物库。为此，我们将在PLGA NP药物载体核心上设计一个表面层，由(a)聚乙二醇（PEG）和基质金属蛋白酶（MMP）特异性底物肽（MMP底物）的偶联物和(b)反式激活转录激活物（TAT）蛋白片段（TAT肽，TATp）组成。每种成分的功能是：(i) PEG将在存在时屏蔽TATp和NPs，阻止PTNPs与通往肿瘤的非癌组织之间的相互作用；（ii）当PTNPs暴露于在卵巢上皮性肿瘤中过表达的MMPs （MMP-2, MMP-9）时，MMP底物会使PEG脱落；（iii）然后暴露的TATp将促进肿瘤细胞中PTNPs的细胞摄取和保留。潜在的假设是：(i)更特异性地集中在肿瘤周围区域的MMPs可以用来切割MMP底物并将聚合NPs从聚乙二醇化形式转化为覆盖有TATp的形式，并且（ii）这种转化将使NPs以肿瘤特异性的方式与肿瘤细胞相互作用。为了证明这一假设，我们将通过制备tat - plga偶联和PEG-MMP底物- plga偶联的NPs或先制备tat - plga偶联的NPs，然后再偶联PEG-MMP底物来制备PTNPs （Aim 1）。同时，在Aim 2中，我们将在人卵巢癌原位异种移植模型中测定正常组织、腹水和肿瘤组织中的体内MMP水平。这些信息将用于评估新的NPs在体外的细胞摄取、细胞内运输和PTNPs递送紫杉醇的功效。新型PTNPs应提供肿瘤特异性的细胞内药物递送，从而降低总剂量需求，提高抗肿瘤疗效，最大限度地发挥卵巢癌IP化疗的药代动力学优势。这项拟议的研究将是迈向更有效和安全的晚期卵巢癌管理的重要一步。

DESCRIPTION (provided by applicant): Intraperitoneal (IP) administration of anti-cancer drugs is a theoretically compelling therapeutic option for epithelial ovarian cancer. However, translation of the theoretical advantage to clinical benefits is hampered by difficulties in IP chemotherapy due to several reasons including short residence time of drugs in the peritoneum, potential of pan-peritoneal toxicity, and insufficient intracellular uptake/accumulation of the anti-cancer drugs. We propose to develop a new form of polymeric nanoparticles (NPs) that will overcome these problems. The LONG TERM GOAL of our research is to develop a tumor-specific nanocarrier of anti-cancer drugs for safe and efficient IP chemotherapy of ovarian cancer. The OBJECTIVE of this study is to create poly(lactic-co- glycolic acid) (PLGA) NPs as a carrier of paclitaxel, which are inert in normal tissues but transform to a reactive form in the peritumoral region (Peritumorally Transformable NPs or PTNPs). This will allow the NPs to have a minimal interaction with non-cancerous tissues, yet be readily taken up and accumulate in ovarian tumor cells providing an intracellular drug reservoir. To this end, we will engineer a surface layer on the PLGA NP drug carrier core, consisting of (a) a conjugate of polyethylene glycol (PEG) and matrix metalloproteinase (MMP) specific substrate peptide (MMP substrate), and (b) a fragment of trans- activating transcriptional activator (TAT) protein (TAT peptide, TATp). The function of each component is that (i) PEG will shield the TATp and NPs when present, preventing interactions between PTNPs and non- cancerous tissues en route to the tumors; (ii) MMP substrate will allow the PEG to cleave off when the PTNPs are exposed to MMPs (MMP-2, MMP-9), which are overexpressed in the epithelial ovarian tumors; and (iii) then exposed TATp will promote cellular uptake and retention of the PTNPs in the tumor cells. The underlying HYPOTHESES are that (i) MMPs that are more specifically concentrated in the peritumoral region can be utilized to cleave MMP substrate and transform polymeric NPs from a PEGylated form to one coated with TATp, and (ii) this transformation will enable the NPs to interact with tumor cells in a tumor-specific manner. To prove this hypothesis, we will create PTNPs by preparing NPs with TATp-PLGA conjugate and PEG-MMP substrate-PLGA conjugate or preparing NPs with TATp-PLGA conjugate first and then conjugating PEG-MMP substrate (Aim 1). Simultaneously, in Aim 2, we will determine in-vivo MMP levels in normal tissues, ascites, and tumor tissues in an orthotopic xenograft model of human ovarian cancer. This information will be used in evaluating the new NPs in vitro with respect to cellular uptake, intracellular trafficking, and the efficacy of paclitaxel delivered by the PTNPs. The novel PTNPs should provide tumor-specific intracellular drug delivery, which would reduce the total dose requirement, improve the anti-tumor efficacy, and maximize the pharmacokinetic advantage of IP chemotherapy of ovarian cancers. The proposed study will be a significant step toward more effective and safe management of advanced ovarian cancers. PUBLIC HEALTH RELEVANCE: We propose to develop a tumor-specific nanocarrier of anti-cancer drugs for safe and efficient intraperitoneal (IP) chemotherapy of ovarian cancer. IP chemotherapy is a theoretically compelling therapeutic option for epithelial ovarian cancer, but translation of this theoretical advantage to clinical benefits is hampered by difficulties in IP drug delivery. We aim to overcome these challenges by engineering a novel nanocarrier that will have a minimal interaction with non-cancerous tissues, yet be readily taken up and accumulate in the tumor cells providing an intracellular drug reservoir, through peritumoral surface transformation.