Modular approach for the delivery of antibodies into the cytoplasm of cells

摘要 许多细胞内靶点对小分子药物不敏感，因为它们缺乏天然配体， 配体结合位点。此外，即使小分子药物可以结合所需的靶蛋白，它也可能不能结合。 有效抑制蛋白质功能。小分子药物能够破坏两种药物之间的相互作用 蛋白质特别难以鉴定。此外，即使在其中小分子药物被施用的情况下， 确定，它必须能够到达其靶位点，具有良好的药代动力学特性和最小的关闭， 目标毒性。这些严格的要求导致开发时间长， 小分子药物已经成功地转化为临床，尽管几十年的研究和 无数的高通量屏幕。 治疗性单克隆抗体作为癌症治疗剂已经取得了相当大的成功，但是它们不能有效地治疗癌症。 跨细胞膜限制了它们的目标分泌或膜相关抗原。如果抗体 可以有效地传递到活细胞的胞质溶胶中，这将显着增加可能的 可下药的目标抗体可以被开发成以高特异性结合几乎任何暴露的蛋白质表位 和亲和力。如果抗体能够 从抑制蛋白质功能，到驱动蛋白质相互作用，再到标记， 用于蛋白体降解的蛋白质。毫不奇怪，已经进行了许多尝试来递送抗体 但一个强大而有效的方法还有待确定。本提案的总体目标是 开发一种模块化方法，将抗体有效地递送到活细胞的细胞质中。 最近，我们开发了一种新的生物缀合策略，使位点特异性和共价连接 小分子、蛋白质和酶对IgG的反应。利用该技术，我们筛选了多种IgG， 结合物被递送到活细胞的胞质溶胶中的能力，并鉴定了可以 在亚微摩尔浓度的IgG下以约60%的效率进行细胞质递送， 细胞毒我们方法的模块化性质不仅允许轻松交换任何“现成”的IgG 我们的系统，而且还保留了IgG可变区的结合亲和力。 在这项提案中，我们计划进一步优化我们的抗体输送技术，并评估抗体的能力 递送到细胞质中以抑制正常的细胞内功能或靶向细胞内蛋白质进行降解。 本提案的具体目标是：目标1。优化IgG结合物和条件， 目标2.开发可以靶向细胞内蛋白质降解的IgG缀合物;目标3.发展 并优化用于体内抗体细胞质递送的制剂。

ABSTRACT Many intracellular targets are not susceptible to small molecule drugs because they lack natural ligands or even ligand binding sites. Moreover, even if a small molecule drug can bind a desirable target protein, it may not be effective in inhibiting protein function. Small molecules drugs capable of disrupting interactions between two proteins have been particularly difficult to identify. Further, even in cases where a small molecule drug is identified, it must be capable of reaching its target site with good pharmacokinetic properties and minimal off- target toxicity. These stringent requirements have led to long development times and a very small fraction of small molecule drugs that have been successfully translated into the clinic, despite decades of research and countless high-throughput screens. Therapeutic monoclonal antibodies have had considerable success as cancer therapeutics, but their inability to cross cell membranes has restricted their targets to secreted or membrane-associated antigens. If antibodies could be efficiently delivered into the cytosol of living cells, it would significantly increase the number of possible druggable targets. Antibodies can be developed to bind nearly any exposed protein epitope, with high specificity and affinity. There are a countless number of therapeutic possibilities that could be pursued if antibodies could be effectively delivered into cells, from inhibiting protein function, to driving proteins interactions, to tagging proteins for proteosomal degradation. Not surprisingly, numerous attempts have been made to deliver antibodies into cells, but a robust and efficient approach has yet to be identified. The overall goal of this proposal is to develop a modular approach to efficiently deliver antibodies into the cytoplasm of living cells. Recently, we developed a novel bioconjugation strategy that enables the site-specific and covalent attachment of small molecules, proteins, and enzymes to IgG. Utilizing this technology, we screened a variety of IgG conjugates in their ability to be delivered into the cytosol of living cells and identified conjugates that could be cytoplasmically delivered with a ~60% efficiency at sub-micromolar concentrations of IgG with minimal cytotoxicity. The modular nature of our approach not only allows for any `off-the-shelf' IgG to be easily swapped into our system, but also preserves the binding affinity of the IgG variable region. In this proposal, we plan to further optimize our antibody-delivery technology and evaluate the ability of antibodies delivered into the cytoplasm to inhibit normal intracellular function or target intracellular proteins for degradation. The specific aims for this proposal are: Aim 1. Optimize IgG conjugates and conditions for maximum cytoplasmic delivery; Aim 2. Develop IgG conjugates that can target intracellular proteins for degradation; Aim 3. Develop and optimize formulations for cytoplasmic delivery of antibodies in vivo.