Coiled-coil Based Drug-Free Macromolecular Therapeutics

描述（由申请人提供）：非霍奇金淋巴瘤（NHL）是一种流行的癌症，2008年在美国估计诊断出66，000例病例，自1980年以来发病率翻了一番。尽管在FDA批准Rituxan后NHL的治疗得到了极大的改善，但在至少三分之一的患者中仍然发生对当前治疗无反应的屈光性恶性肿瘤，这表明需要改进治疗策略。B细胞NHL的最可靠的生物标志物和治疗靶标之一是CD 20，其是当与互补抗体结合时保留在细胞表面上的非内化抗原。CD 20结合抗体与二抗的交联导致这些细胞的凋亡。该项目的总体目标是产生新的、无药物的大分子治疗剂，用于改善NHL的治疗。提出了一种新的基于N-（2-羟丙基）甲基丙烯酰胺（HPMA）接枝共聚物介导的B细胞表面卷曲螺旋异二聚体形成的凋亡诱导系统。该设计的基本原理是不存在低分子量药物，以及B细胞表面的CD 20交联导致细胞凋亡的事实。该系统由形成反平行异二聚体的一对互补卷曲螺旋肽、1F 5抗CD 20抗体的Fab'片段和HPMA共聚物组成。一个肽与Fab'片段缀合，另一个以多个接枝物与聚HPMA缀合。先前设计了一对带相反电荷的五肽（CCE和CCK），其形成具有高度生物识别性的反平行卷曲螺旋异二聚体。据推测，CCK和CCE肽的独特生物识别可以成为设计一类新型大分子治疗药物的基础。实际上，将CD 20 + Raji B细胞暴露于Fab ′-CCE导致细胞表面通过抗原-抗体片段生物识别被CCE肽的多个拷贝修饰。进一步暴露的CCE修饰的细胞与HPMA共聚物接枝与CCK的多个拷贝导致在细胞表面的CCE-CCK卷曲螺旋异二聚体的形成。这第二个生物识别事件诱导CD 20受体的交联并触发Raji B细胞的凋亡。系统将根据初步数据进行优化。将设计并评价含有L-和/或D-氨基酸残基的较短卷曲螺旋形成序列。HPMA接枝共聚物介导的卷曲螺旋形成在细胞表面伴随受体交联和细胞凋亡诱导将在体外评估使用五种细胞类型和三种细胞凋亡测定。重要的是，将在动物模型中评估无药物大分子治疗剂的功效和生物相容性。将评价身体分布、剂量和给药频率对治疗疗效的影响，以选择先导化合物和最佳治疗方式。最后，这一新概念将发展成为一种新的治疗实体，即无药物大分子治疗学。

DESCRIPTION (provided by applicant): Non-Hodgkin's lymphoma (NHL) is a prevalent cancer with an estimated 66,000 cases diagnosed in the United States in 2008, with the incidence doubling since 1980. Although treatments for NHLs greatly improved following the FDA approval of Rituxan, refractive malignancies still occur that are nonresponsive to current therapies in at least a third of all patients, indicating that improved treatment strategies are needed. One of the most reliable biomarkers and therapeutic targets for B cell NHL is CD20, which is a non- internalizing antigen that remains on the cell surface when bound to a complementary antibody. The crosslinking of CD20-bound antibodies with a secondary antibody results in apoptosis of these cells. The overall goal of this project is to generate new, drug-free macromolecular therapeutics for improved treatment of NHL. A new apoptosis induction system is proposed which is based on N-(2- hydroxypropyl)methacrylamide (HPMA) graft copolymer mediated formation of coiled-coil heterodimers at B- cell surface. The rationale of the design is the absence of low molecular weight drugs and the fact that crosslinking of CD20 at B-cell surface results in apoptosis. The system is composed of a pair of complementary coiled-coil peptides forming antiparallel heterodimers; Fab' fragment of the 1F5 anti-CD20 antibody; and HPMA copolymer. One peptide is conjugated to the Fab' fragment, the other is conjugated in multiple grafts to polyHPMA. A pair of oppositely charged pentaheptad peptides (CCE and CCK) that formed antiparallel coiled-coil heterodimers with a high degree of biorecognition was previously designed. It was hypothesized that the unique biorecognition of CCK and CCE peptides could be a basis for the design of a novel class of macromolecular therapeutics. Indeed, the exposure of CD20+ Raji B cells to Fab'-CCE resulted in the decoration of the cell surface with multiple copies of the CCE peptide via antigen-antibody fragment biorecognition. Further exposure of the CCE decorated cells to HPMA copolymer grafted with multiple copies of CCK resulted in the formation of CCE-CCK coiled-coil heterodimers on the cell surface. This second biorecognition event induced crosslinking of CD20 receptors and triggered apoptosis of Raji B cells. The system will be optimized based on the preliminary data. Shorter coiled-coil forming sequences containing L- and/or D-amino acid residues will be designed and evaluated. HPMA graft copolymer mediated coiled-coil formation at cell surface with concomitant receptor crosslinking and apoptosis induction will be assessed in vitro using five cell types and three apoptosis assays. Importantly, the efficacy and biocompatibility of drug-free macromolecular therapeutics will be evaluated in an animal model. Body distribution, impact of the dose and frequency of administration on the efficacy of treatment will be evaluated with the aim to select leading compound(s) and optimal treatment modalities. Finally, this new concept will be developed into a new therapeutic entity, drug-free macromolecular therapeutics.