Metal Chelate Conjugated Dendrimer Constructs for Diagnosis and Therapy

用于诊断和治疗的金属螯合物共轭树枝状聚合物构建体

• 批准号: 8938405
• 负责人: MARTIN W BRECHBIEL
• 金额: $ 60.81万
• 依托单位: DIVISION OF CLINICAL SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8938405
• 关键词: Address; Alkynes; Amines; Antibodies; Avidin; Azides; Biological; Blood Circulation; CCR; Charge; Chelating Agents; Chemistry; Clinical; Collaborations; Complement; Contrast Media; Cystamine; Dendrimers; Development; Diagnosis; Dyes; Electron Transport Complex III; Elements; Excision; Excretory function; Extramural Activities; Gadopentetate Dimeglumine; Generations; Goals; Image; Imaging technology; Immunoglobulin Fragments; Investigation; Kidney; Laboratories; Legal patent; Liver; Lymphatic; Lysine; Magnetic Resonance Imaging; Maleimides; Malignant Neoplasms; Malignant neoplasm of ovary; Maps; Metals; Modality; Molecular Target; Molecular Weight; Monitor; Monoclonal Antibodies; National Institute of Mental Health; Operative Surgical Procedures; Optics; Organ; Peptides; Phase; Polymers; Positron-Emission Tomography; Radiology Specialty; Reagent; Renal clearance function; Reporting; Reproducibility; Research Personnel; Resolution; Safety; Sentinel Lymph Node; Serum Albumin; Shapes; Site; Solubility; Solvents; Sulfhydryl Compounds; Technology; Time; Toxic effect; Translating; Translations; Work; analog; aqueous; base; chelation; imaging modality; interest; intraperitoneal; lipophilicity; novel; optical imaging; response; single photon emission computed tomography; tumor; uptake; vector

Macromolecular MRI contrast agents based upon dendrimers obviate many deficiencies of serum albumin or linear polymer based MRI contrast agents of comparable size. This is due to their iterative synthesis promotes controlled size and shape of the dendrimer concomitantly generating the means for reproducible chemistry key to the clinical translation of such agents. To create MRI contrast agents with dendrimers, the terminal primary amines of dendrimers are modified with chelated Gd(III) technology developed in the Section. Historically, these reagents demonstrated a molar relaxivity 6 times that of Magnevist, the currently approved MRI contrast agent. Macromolecular chelate conjugated dendrimer based Gd(III) MR contrast agents can be tuned for various applications by adjusting fundamental criteria: generation (MW & size), core elements (lipophilicity & charge), PEG conjugation (prolong circulation and minimize liver & other organ uptake), lysine co-administration (renal clearance), and conjugation to targeting vectors (molecular targeting). Dendrimer based agents have also been selectively targeted, not only by conjugation to antibodies, but by other vectors, such as avidin to deliver exceptionally high levels of Gd(III) into disseminated intraperitoneal ovarian cancer tumor. This was done in conjunction with an optical imaging agent in parallel with our creation of multi-modality dendrimer based imaging agents. The incorporation of a NIR optical imaging dye into the MRI agent added an enhanced level of sensitivity to complement the resolution of the MRI imaging and provided an additional level of sensitivity for the imaging of lymphatics and sentinel nodes that can be envisioned as being translated to an intraoperative scenario wherein MRI imaging and mapping would supplement real-time surgical intervention and excision of malignancy. While the chemistry established the ability to create such macromolecular agents, the imaging resulted in compromised targeting which defined that these agents require very careful systematic investigation combined with equally careful defined characterization. New chelation chemistry for conjugation of Gd(III) complexes to dendrimer has been prompted by the need to re-invent this field moving it from aqueous chemistry to organic phase solvents to enhance both characterization and consistency of yields. This chemistry has also evolved specialized analogs of established bifunctional chelation agents (patent filed) to address development of site-specific conjugation chemistry required for actively targeted dendrimer based imaging agents e.g, maleimides targeting a unique thiol residue, or agents functionalized with alkyne or azide groups for click chemistry conjugation strategies. NFS related Gd(III) toxicity resultant from use of less than adequately stable MRI contrast agents combined with low renal excretion prompted a new directionality in the choice of bifunctional chelating agent towards the use of DOTA as the bifunctional chelating agent. With the Gd(III) complex pre-formed prior to conjugation to all targeting vectors, toxicity concerns have been traversed. This effort was put into place with all of the MR contrast projects fully migrated to exclusive use of pre-complexation of the Gd(III) conjugate strategy using DOTA also eliminating characterization complexity resulting from the creation of exceedingly difficult to characterize mixtures of products that limited reproducibility complicating clinical translation. Results validated this transformation not only as a successful strategy despite warnings of decreased solubility (not true), but provided a far greater molar relaxivity. We reported a 5-fold enhancement over the prior technology while concurrently decreasing the actual physical amount of Gd(III) conjugated to the dendrimer by 65% further increasing the safety margin. The impact of this result reaches across to all macromolecular MR contrast agents regardless of platformto fully address safety, characterization, and reproducibility thereby furthering an entire fields potential for clinical translation of such agents. The exquisite advantages of dendrimer based agents over low molecular weight agents, e.g. Magnevist, continues to be very clearly demonstrated. In parallel to this improvement to abrogate toxicity concerns that has resulted in superior dendrimer based agents, the ability to finally move forward with actively targeted dendrimer based contrast agents that are discrete characterized agents was achieved through conjugation of a cystamine core dendrimer derived dendron conjugated in a 1:1 form with an antibody fragment. While successful, both isolation and purification were challenging with the dendrimer generation employed as well as relatively lower relaxivity results indicating the need to move onwards to a higher dendrimer generation. This investigation continues in parallel with the creation of a PEG appended trifunctional imaging agent that will permit incorporation of a radiological probe (PET imaging) with an optical probe. Established collaborations with Radiology, CC, the PET Dept, CC, NIMH, and extramural researchers at Johns Hopkins continue to be fruitful.

基于树枝状聚合物的大分子MRI对比剂消除了血清白蛋白或线性聚合物基于线性聚合物的MRI对比度的许多缺陷。这是由于它们的迭代合成促进了树枝状大分子的受控大小和形状，从而产生了可重复的化学方法的平均值，这是此类药物临床翻译的关键。为了创建与树枝状聚合物的MRI对比剂，树枝状聚合物的末端原发胺通过本节中开发的螯合GD（III）技术进行了修饰。从历史上看，这些试剂表现出摩尔松弛性的6倍，即Magnevist（当前已批准的MRI对比剂）。 Macromolecular chelate conjugated dendrimer based Gd(III) MR contrast agents can be tuned for various applications by adjusting fundamental criteria: generation (MW & size), core elements (lipophilicity & charge), PEG conjugation (prolong circulation and minimize liver & other organ uptake), lysine co-administration (renal clearance), and conjugation to靶向载体（分子靶向）。基于树枝状聚合物的剂也是选择性的，不仅是通过与抗体结合来选择性的，而且还通过其他载体（例如Avidin）将异常高水平的GD（III）（III）传递到散布的腹膜内卵巢癌肿瘤中。这是与光学成像剂同时完成的，与我们创建的基于多模式的基于树枝状聚合物的成像剂。将NIR光学成像染料掺入MRI剂中增加了增强的敏感性，以补充MRI成像的分辨率，并为淋巴结和哨兵节点的成像提供了额外的敏感性，可以预见，可以将其转化为术中MRI Imigign和映射的验证和映射时，可以将其转化为术中的术语和映射。虽然化学基础建立了创建这种大分子药物的能力，但成像导致靶向损害，这确定了这些药物需要非常仔细的系统研究，并结合了同样仔细的定义表征。需要将其从水性化学变为有机相溶剂转移到有机相位溶剂以提高特性和一致性的产量，这引起了GD（III）复合物与树枝状聚合物结合的新螯合化学。这种化学还发展了既定的双功能螯合剂（已提交的专利）的专业类似物，以解决针对基于靶向树突的成像剂的现场特异性共轭化学的开发，例如，针对独特硫醇残留物的MaleImides，或与Alkyne或Azide Clips Chips Chiptertion Conjugations Conjugugations conconjugugations of Uniquer Thiol Recaste，或者具有抗氧化二聚体化学。 NFS相关的GD（III）毒性是由于使用较少稳定的MRI对比剂与低肾脏排泄相结合的毒性引起的，促使选择双功能螯合剂在使用DOTA作为双功能螯合剂方面具有新的方向性。随着GD（III）复合物在与所有靶向矢量结合之前预先形成的复合物，毒性问题已经遍历。所有MR对比度项目都完全迁移到使用DOTA的GD（III）共轭策略的独家使用，也消除了由于产生极其难以表征的混合物而导致的表征复杂性，从而消除了限制可重复性复杂性临床转换的产物的混合物。尽管警告说溶解度降低（不正确），但结果验证了这种转变，不仅是成功的策略，而且提供了更大的摩尔松弛性。我们报道了对先前技术的增强5倍，同时减少了与树枝状聚合物相连的GD（III）的实际物理量，从而进一步增加了安全边缘。该结果的影响涉及所有大分子MR对比剂，无论平台如何完全解决安全性，表征和可重复性，从而进一步推动了整个领域的临床翻译潜力。基于树枝状聚合物的剂优于低分子量剂，例如Magnevist，仍然非常清楚地证明。与这种取得的改善，消除了导致基于树突的毒剂的毒性问题，最终能够通过与基于树枝状的对比剂进行积极靶向靶向的对比剂的能力，通过与cystamine core Dendrrimer衍生的树木衍生的树木相结合，在与Antib a antib中的cypody conjugtiby conjugation相结合来实现。尽管成功，但隔离和纯化都在挑战，而采用的树枝状聚合物产生以及相对较低的放松性结果，表明需要继续前进到更高的树枝状聚合物产生。这项研究与创建PEG附加的三功能成像剂同时进行，该成像剂将允许将放射学探针（PET成像）与光学探针合并。约翰·霍普金斯（Johns Hopkins）与放射学，CC，宠物部，CC，NIMH和外部研究人员建立了合作。