Bio-Imaging of Colorectal Cancer Models Using Near Infrared Labeled Epidermal Growth Factor
Bio-Imaging of Colorectal Cancer Models Using Near Infrared Labeled Epidermal Growth Factor
复制标题
使用近红外标记的表皮生长因子对结直肠癌模型进行生物成像
作者：
Gadi Cohen;S. Lecht;H. Arien;K. Ettinger;Orit Amsalem;M. Oron;E. Yavin;D. Prus;S. Benita;A. Nissan;P. Lazarovici
针对表皮生长因子受体 (EGFR) 的新策略促进了单克隆抗体的临床开发，用于治疗转移性结直肠癌 (mCRC)，但只有野生型 KRAS 和 EGFR 基因拷贝数增加的患者亚组对这些药物有反应。此外，不可避免地会出现对 EGFR 阻断的耐药性，使得未来的治疗变得困难。新型生物成像 (BOI) 方法可能有助于量化 mCRC 组织中的 EGFR，从而补充免疫组织化学方法，指导这些患者的未来治疗。本研究的目的是利用体外和体内原位肿瘤 CRC 模型和离体人类 CRC 组织，探索近红外标记 EGF (EGF-NIR) 在 CRC 生物成像中的有用性。我们描述了 EGF-NIR 的制备和表征，并使用一组类似于人类 CRC 组织异质性的 CRC 细胞培养模型的 BOI 来研究结合。 EGF-NIR 特异性、选择性地与表达 EGFR 的 CRC 细胞结合，EGF-NIR 信号与背景比 (SBR) 的强度反映了 EGFR 水平，剂量反应和时程成像实验为 BOI 量化 EGFR 水平提供了最佳条件。对患有 HT-29 原位 CRC 肿瘤的小鼠进行 EGF-NIR 成像表明，EGF-NIR 从肿瘤中清除的速度较慢，并且在注射两天后，肿瘤与正常邻近组织之间的 SBR 达到最高。此外，解剖组织的图像显示 EGF-NIR 在肿瘤和肝脏中积累。 EGF-NIR特异性地强烈标记EGFR阳性人类CRC组织，而邻近的CRC组织和EGFR阴性组织表达微弱的NIR信号。本研究强调使用 EGF-NIR 进行临床前研究。与其他方法相结合，EGF-NIR 可以为 CRC 组织中 EGFR 表达测量的标准化提供额外的生物成像特定工具。
Novel strategies that target the epidermal growth factor receptor (EGFR) have led to the clinical development of monoclonal antibodies, which treat metastatic colorectal cancer (mCRC) but only subgroups of patients with increased wild type KRAS and EGFR gene copy, respond to these agents. Furthermore, resistance to EGFR blockade inevitably occurred, making future therapy difficult. Novel bio-imaging (BOI) methods may assist in quantization of EGFR in mCRC tissue thus complementing the immunohistochemistry methodology, in guiding the future treatment of these patients. The aim of the present study was to explore the usefulness of near infrared-labeled EGF (EGF-NIR) for bio-imaging of CRC using in vitro and in vivo orthotopic tumor CRC models and ex vivo human CRC tissues. We describe the preparation and characterization of EGF-NIR and investigate binding, using BOI of a panel of CRC cell culture models resembling heterogeneity of human CRC tissues. EGF-NIR was specifically and selectively bound by EGFR expressing CRC cells, the intensity of EGF-NIR signal to background ratio (SBR) reflected EGFR levels, dose-response and time course imaging experiments provided optimal conditions for quantization of EGFR levels by BOI. EGF-NIR imaging of mice with HT-29 orthotopic CRC tumor indicated that EGF-NIR is more slowly cleared from the tumor and the highest SBR between tumor and normal adjacent tissue was achieved two days post-injection. Furthermore, images of dissected tissues demonstrated accumulation of EGF-NIR in the tumor and liver. EGF-NIR specifically and strongly labeled EGFR positive human CRC tissues while adjacent CRC tissue and EGFR negative tissues expressed weak NIR signals. This study emphasizes the use of EGF-NIR for preclinical studies. Combined with other methods, EGF-NIR could provide an additional bio-imaging specific tool in the standardization of measurements of EGFR expression in CRC tissues.