Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
Department of Pharmacology, Weill Cornell Medical College, New York, NY, USA.
Mol Imaging Biol. 2021 Feb;23(1):84-94. doi: 10.1007/s11307-020-01535-3. Epub 2020 Sep 9.
Targeted delivery in vivo remains an immense roadblock for the translation of nanomaterials into the clinic. The greatest obstacle is the mononuclear phagocyte system (MPS), which sequesters foreign substances from general circulation and causes accumulation in organs such as the liver and spleen. The purpose of this study was to determine whether attaching an active targeting antibody, 5B1, to the surface of gold nanoparticles and using clodronate liposomes to deplete liver and splenic macrophages could help to minimize uptake by MPS organs, increase targeted delivery to CA19.9-positive pancreatic tumors, and enhance pancreatic tumor delineation.
To produce the antibody-gold nanoparticle conjugate (Ab-AuNP), the Ab was conjugated to p-isothiocyanatobenzyl-desferrioxamine (p-SCN-DFO) and subsequently conjugated to NHS-activated gold nanoparticles. The Ab-AuNP was characterized by transmission electron microscopy (TEM) and atomic force microscopy (AFM). Modified Lindmo assay was performed to assess binding affinity and internalization potential in vitro. The Ab-AuNP was radiolabeled with Zr and injected into CA19.9-positive BxPc-3 pancreatic orthotopic tumor-bearing mice pretreated with or without clodronate liposomes for PET imaging and biodistribution studies. Inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis was used to confirm delivery of gold nanoparticles to BxPc-3 pancreatic subcutaneous xenografts.
Mice pretreated with clodronate liposomes in an orthotopic setting demonstrated decreased liver uptake at early time points (12.2 ± 2.3 % ID/g vs. 22.8 ± 3.8 % ID/g at 24 h) and increased tumor uptake at 120 h (13.8 ± 8.0 % ID/g vs. 6.0 ± 1.2 % ID/g). This allowed for delineation of orthotopic pancreatic xenografts in significantly more mice treated with clodronate (6/6) than in mice not treated with clodronate (2/6) or mice injected with gold nanoparticles labeled with a nonspecific antibody (0/5).
The combination of clodronate liposomes and an active targeting antibody on the surface of gold nanoparticles allowed for PET/CT imaging of subcutaneous and orthotopic pancreatic xenografts in mice.
靶向递送至体内仍然是将纳米材料转化为临床应用的巨大障碍。最大的障碍是单核吞噬细胞系统（MPS），它将外来物质从体循环中隔离出来，并导致肝脏和脾脏等器官的积累。本研究的目的是确定将活性靶向抗体 5B1 附着在金纳米粒子表面并用氯膦酸脂质体耗尽肝和脾巨噬细胞是否有助于减少 MPS 器官的摄取，增加对 CA19.9 阳性胰腺肿瘤的靶向递药，并增强胰腺肿瘤的描绘。
为了生产抗体-金纳米粒子缀合物（Ab-AuNP），将抗体与对异硫氰酸苯甲基去铁胺（p-SCN-DFO）缀合，然后与 NHS 激活的金纳米粒子缀合。通过透射电子显微镜（TEM）和原子力显微镜（AFM）对 Ab-AuNP 进行了表征。进行了改良的 Lindmo 测定以评估体外结合亲和力和内化潜力。用 Zr 标记 Ab-AuNP，并在预处理或不预处理氯膦酸脂质体的情况下将其注射到 CA19.9 阳性 BxPc-3 胰腺原位肿瘤荷瘤小鼠中，用于 PET 成像和生物分布研究。电感耦合等离子体-原子发射光谱法（ICP-OES）分析用于证实金纳米粒子递送到 BxPc-3 胰腺皮下异种移植物。
在原位设置中用氯膦酸脂质体预处理的小鼠在早期时间点（24 小时时为 12.2±2.3％ID/g 与 22.8±3.8％ID/g）肝脏摄取减少，120 小时时肿瘤摄取增加（13.8±8.0％ID/g 与 6.0±1.2％ID/g）。这使得在用氯膦酸（6/6）处理的小鼠中明显更多地描绘出原位胰腺异种移植物，而不是未用氯膦酸（2/6）处理的小鼠或用非特异性抗体标记的金纳米粒子（0/5）处理的小鼠。
氯膦酸脂质体和金纳米粒子表面上的活性靶向抗体的组合允许在小鼠中进行皮下和原位胰腺异种移植物的 PET/CT 成像。
