Department of Medicine II, University Hospital, LMU Munich, Munich, Germany.
Department of Radiation Oncology, Hospital of Ludwig-Maximilians-University, Munich, Germany.
Gastroenterology. 2021 Sep;161(3):996-1010.e1. doi: 10.1053/j.gastro.2021.05.055. Epub 2021 Jun 25.
BACKGROUNDS & AIMS: Fluoropyrimidine c (5-fluorouracil [5FU]) increasingly represents the chemotherapeutic backbone for neoadjuvant, adjuvant, and palliative treatment of pancreatic ductal adenocarcinoma (PDAC). Even in combination with other agents, 5FU efficacy remains transient and limited. One explanation for the inadequate response is insufficient and nonspecific delivery of 5FU to the tumor.
We designed, generated, and characterized 5FU-incorporated systematic evolution of ligands by exponential enrichment (SELEX)-selected epidermal growth factor receptor (EGFR)-targeted aptamers for tumor-specific delivery of 5FU to PDAC cells and tested their therapeutic efficacy in vitro and in vivo.
5FU-EGFR aptamers reduced proliferation in a concentration-dependent manner in mouse and human pancreatic cancer cell lines. Time-lapsed live imaging showed EGFR-specific uptake of aptamers via clathrin-dependent endocytosis. The 5FU-aptamer treatment was equally effective in 5FU-sensitive and 5FU-refractory PDAC cell lines. Biweekly treatment with 5FU-EGFR aptamers reduced tumor burden in a syngeneic orthotopic transplantation model of PDAC, in an autochthonously growing genetically engineered PDAC model (LSL-Kras;LSL-Trp53;Ptf1a-Cre [KPC]), in an orthotopic cell line-derived xenograft model using human PDAC cells in athymic mice (CDX; Crl:NU-Foxn1), and in patient-derived organoids. Tumor growth was significantly attenuated during 5FU-EGFR aptamer treatment in the course of follow-up.
Tumor-specific targeted delivery of 5FU using EGFR aptamers as the carrier achieved high target specificity; overcame 5FU resistance; and proved to be effective in a syngeneic orthotopic transplantation model, in KPC mice, in a CDX model, and in patient-derived organoids and, therefore, represents a promising backbone for pancreatic cancer chemotherapy in patients. Furthermore, our approach has the potential to target virtually any cancer entity sensitive to 5FU treatment by incorporating 5FU into cancer cell-targeting aptamers as the delivery platform.
氟嘧啶类药物 C（5-氟尿嘧啶[5FU]）越来越多地成为新辅助、辅助和姑息治疗胰腺导管腺癌（PDAC）的化疗基础。即使与其他药物联合使用，5FU 的疗效仍然是短暂的和有限的。对反应不足的一种解释是 5FU 向肿瘤的输送不足和非特异性。
我们设计、生成和表征了 5FU 结合的表皮生长因子受体（EGFR）靶向系统进化配体的指数富集（SELEX）选择的适体，用于将 5FU 特异性递送至 PDAC 细胞，并在体外和体内测试其治疗效果。
5FU-EGFR 适体以浓度依赖的方式降低了小鼠和人胰腺癌细胞系的增殖。延时活细胞成像显示，适体通过网格蛋白依赖性内吞作用特异性摄取 EGFR。5FU-适体治疗对 5FU 敏感和 5FU 耐药的 PDAC 细胞系同样有效。每周两次用 5FU-EGFR 适体治疗，可减少胰腺导管腺癌同基因原位移植模型、自主生长的基因工程胰腺导管腺癌模型（LSL-Kras；LSL-Trp53；Ptf1a-Cre [KPC]）、在裸鼠中使用人胰腺癌细胞的原位细胞系衍生异种移植模型（CDX；Crl：NU-Foxn1）和患者衍生的类器官中的肿瘤负担，肿瘤生长在 5FU-EGFR 适体治疗过程中显著受到抑制。
使用 EGFR 适体作为载体的 5FU 肿瘤特异性靶向递送实现了高靶向特异性；克服了 5FU 耐药性；并在同基因原位移植模型、KPC 小鼠、CDX 模型和患者衍生的类器官中证明了有效性，因此代表了患者胰腺癌化疗的一种有前途的基础。此外，我们的方法通过将 5FU 纳入作为递送平台的癌细胞靶向适体，有可能针对任何对 5FU 治疗敏感的实体瘤。
