Echogenic Polymersomes for Triggered Contents Release

用于触发内容物释放的回声聚合物囊泡

• 批准号: 8859700
• 负责人: BIN GUO
• 金额: $ 29.89万
• 依托单位: NORTH DAKOTA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-05 至 2019-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8859700
• 关键词: Acoustics; Angiogenesis Inhibitors; Antineoplastic Agents; Blood Circulation; Cancer Cell Growth; Castration; Cell Culture Techniques; Characteristics; Cleaved cell; DU145; Diagnostic; Disease remission; Drug Carriers; Drug Delivery Systems; Drug Formulations; Drug resistance; Drug toxicity; Effectiveness; Encapsulated; Frequencies; Gases; Glutathione; Histone Deacetylase Inhibitor; Hypoxia; Image; Link; Liposomes; Measures; Mechanics; Mediating; Membrane; Molecular Weight; Mus; Organ; PC3 cell line; Penetration; Peptides; Pharmaceutical Preparations; Physiologic pulse; Polymers; Preparation; Process; Property; Prostatic Neoplasms; Reducing Agents; Regimen; Reporting; Resistance; Stimulus; Structure; Testing; Therapeutic; Thick; Time; Tumor Tissue; Ultrasonography; United States Food and Drug Administration; Vesicle; attenuation; cancer cell; cancer stem cell; castration resistant prostate cancer; copolymer; cytotoxicity; docetaxel; extracellular; imaging modality; mouse model; prostate cancer cell; public health relevance; tumor

 DESCRIPTION: Polymersomes are vesicles prepared from synthetic, amphiphilic-block copolymers. They have several advantages over liposomes, including enhanced stability, longer circulation times, mechanical robustness, and the ability to carry large quantities of hydrophobic and hydrophilic drug molecules. The hydrophilic block of the copolymers is usually polyethyleneglycol (PEG), imparting the long-circulating property to the resultant polymersomes. Because of robustness, the polymersomes require a stimulus to sufficiently disturb the compact bilayer, and to release the encapsulated contents. Although liposomes are extensively studied for drug delivery applications, the potential of polymersomes for targeting, triggered contents release, and simultaneous imaging remains largely unexplored and undeveloped. In this application, we are proposing to synthesize amphiphilic block copolymers, and prepare long-circulating polymersomes. The polymersomes will be actively targeted to tumor tissues, and triggered to release the encapsulated contents upon internalization in the cancer cells. In addition, we will encapsulate gas bubbles in the polymersomes to render them echogenic. This will allow us to perform simultaneous ultrasound imaging, and exert an addition control over contents release employing diagnostic frequency ultrasound. The effectiveness of the proposed multimodal polymersomes will be demonstrated using spheroid cultures and orthotopic mouse model for castration resistant prostate cancer. The Aims of the proposed studies are summarized below. (1) Synthesis of amphiphilic block copolymers, and preparation of echogenic, trigger-releasable polymersomes. We will synthesize bock copolymers containing PEG as the hydrophilic part. The structure as well as the molecular weight of the hydrophobic block will be systematically varied to optimize the polymersome formation process. In order to impart stimuli-responsive property, we will connect the synthesized hydrophilic and hydrophobic polymer blocks via either a reduction-sensitive (for intracellular release) or a hypoxia-sensitive link (for extracellular release). For active targeting and tumor penetration, we will chemically attach the reported cyclic iRGD peptide to the PEG terminus. Echogenic polymersomes will be prepared from these polymers, encapsulating the angiogenesis inhibitor suntinib (for extracellular release) or the anticancer drug docetaxel, and the histone deacetylase inhibitor mocetinostat (for intracellular release). (2) Acoustic characterization of the echogenic polymersomes. We will demonstrate reduction and hypoxia- mediated release of encapsulated contents employing physiologically-relevant concentrations of the cellular reducing agent, glutathione and hypoxic conditions. Echogenicity of the polymersomes will be investigated using detailed acoustic characterization, measuring attenuation, linear, and nonlinear scattering. We will determine the resonance characteristics. We will determine the threshold excitation level for destruction of these polymersomes by measuring time dependent attenuation under progressively higher acoustic excitations. The effect of ultrasound on altering the rate of content release from the polymersomes will be investigated. Optimum acoustic parameters (excitation frequency, pulse waveform and strength) will be determined for linear and nonlinear (harmonic and subharmonic) imaging modalities. (3) Demonstration of effectiveness of the drug delivery system employing spheroid cell cultures and orthotopic mouse model of castration resistant prostate cancer. We will generate the three dimensional spheroids of the castration resistant, prostate cancer cells to evaluate the effectiveness of our polymersomes to deliver the encapsulated drugs. For intracellular delivery, we will probe the synergistic effects of docetaxel and mocetinostat to overcome drug resistance. We will determine the penetration of the polymersomes, cytotoxicity, and reduction in growth of the cancer cells using the tumor spheroids. Subsequently, we will generate orthotopic mouse models of castration resistant prostate cancer to evaluate the effectiveness of our polymersome formulation to deliver their encapsulated drugs. The effect of applied diagnostic frequency ultrasound will be determined, and the spheroids and the tumors in mice will be imaged. We will further determine the effects of the released drugs in reducing the cancer stem cells, the therapeutic regimen for the formulations, remission of the tumors, and potential toxicity of the drugs in different organs.

 描述：聚合物囊泡是由合成的两亲性嵌段共聚物制备的囊泡。与脂质体相比，它们具有几个优点，包括增强的稳定性、更长的循环时间、机械鲁棒性以及携带大量疏水性和亲水性药物分子的能力。共聚物的亲水性嵌段通常是聚乙二醇（PEG），赋予所得聚合物囊泡长循环性质。由于稳健性，聚合物囊泡需要刺激以充分干扰致密双层，并释放包封的内容物。尽管脂质体被广泛研究用于药物递送应用，但聚合物囊泡用于靶向、触发内容物释放和同时成像的潜力在很大程度上仍未被探索和开发。在此应用中，我们建议合成两亲性嵌段共聚物，并制备长循环聚合物囊泡。聚合物囊泡将主动靶向肿瘤组织，并在癌细胞内化后触发释放包封的内容物。此外，我们将在聚合物囊泡中封装气泡，使其产生回声。这将使我们能够同时进行超声成像，并施加额外的控制内容物释放采用诊断频率超声。将使用球状体培养物和去势抵抗性前列腺癌的原位小鼠模型证明所提出的多峰聚合物囊泡的有效性。拟议研究的目的总结如下。(1)两亲性嵌段共聚物的合成及回声性、可释放药物的聚合物囊泡的制备。我们将合成含有PEG作为亲水部分的嵌段共聚物。疏水嵌段的结构以及分子量将系统地变化以优化聚合物囊泡形成过程。为了赋予刺激响应特性，我们将通过还原敏感性（用于细胞内释放）或缺氧敏感性连接（用于细胞外释放）连接合成的亲水性和疏水性聚合物嵌段。为了主动靶向和肿瘤渗透，我们将报告的环状iRGD肽化学连接到PEG末端。回声聚合物囊泡将由这些聚合物制备，包封血管生成抑制剂suntinib（用于细胞外释放）或抗癌药物多西他赛，以及组蛋白脱乙酰酶抑制剂mocetinostat（用于细胞内释放）。(2)回声聚合物囊泡的声学表征。我们将采用生理相关浓度的细胞还原剂、谷胱甘肽和缺氧条件来证明包封内容物的还原和缺氧介导的释放。将使用详细的声学表征、测量衰减、线性和非线性散射来研究聚合物囊泡的回声。我们将确定共振特性。我们将通过测量逐渐升高的声激发下的时间依赖性衰减来确定这些聚合物囊泡破坏的阈值激发水平。超声波对改变含量的影响 将研究从聚合物囊泡的释放。将确定线性和非线性（谐波和次谐波）成像模式的最佳声学参数（激励频率、脉冲波形和强度）。(3)使用球状体细胞培养物和去势抵抗性前列腺癌的原位小鼠模型证明药物递送系统的有效性。我们将产生去势抵抗性前列腺癌细胞的三维球体，以评估我们的聚合物囊泡递送包封药物的有效性。对于细胞内递送，我们将探索多西他赛和mocetinostat克服耐药性的协同作用。我们将使用肿瘤球状体确定聚合物囊泡的渗透性、细胞毒性和癌细胞生长的减少。随后，我们将产生去势抵抗性前列腺癌的原位小鼠模型，以评估我们的聚合物囊泡制剂递送其包封药物的有效性。将确定应用的诊断频率超声的效果，并将对小鼠中的球体和肿瘤进行成像。我们将进一步确定释放的药物在减少癌症干细胞方面的作用，制剂的治疗方案，肿瘤的缓解以及药物在不同器官中的潜在毒性。