Faculty of Pharmaceutical Sciences, Setsunan University, Osaka, Japan.
Eur J Pharm Biopharm. 2010 Mar;74(3):451-60. doi: 10.1016/j.ejpb.2010.01.001. Epub 2010 Jan 10.
Peanut agglutinin (PNA)-immobilized fluorescent nanospheres were designed as a novel imaging agent for colonoscopy. PNA is a targeting moiety that binds to beta-D-galactosyl-(1-3)-N-acetyl-D-galactosamine, which is the terminal sugar of the Thomsen-Friedenreich antigen that is specifically expressed on the mucosal side of colorectal cancer cells. The in vivo performance of the imaging agent was evaluated using a human colorectal cancer orthotopic animal model. Human colorectal adenocarcinoma cell lines, HT-29, HCT-116, and LS174T, were implanted on the cecal serosa of immune-deficient mice. A loop of the tumor-bearing cecum was made, and the luminal side was treated with the imaging agent. Strong fluorescence was observed at several sites of the cecal mucosa, irrespective of cancer cell type. Microscopic histological evaluation of the cecal mucosa revealed that bright areas with fluorescence derived from the imaging agent and dark areas without the fluorescence well denoted the presence and absence, respectively, of the invasion of implanted cancer cells on the mucosal side. This good correlation showed that PNA-immobilized fluorescent nanospheres recognized millimeter-sized tumors on the cecal mucosa with high affinity and specificity.
花生凝集素 (PNA)-固定化荧光纳米球被设计为结肠镜检查的新型成像剂。PNA 是一种靶向部分，可与 β-D-半乳糖基-(1-3)-N-乙酰-D-半乳糖胺结合，后者是结直肠癌细胞黏膜侧特异性表达的 Thomsen-Friedenreich 抗原的末端糖。该成像剂的体内性能使用人结直肠癌原位动物模型进行了评估。人结直肠腺癌细胞系 HT-29、HCT-116 和 LS174T 被植入免疫缺陷小鼠的盲肠浆膜上。将带有肿瘤的盲肠环切开，并在肠腔侧用成像剂处理。在盲肠黏膜的几个部位观察到强烈的荧光，而与癌细胞类型无关。对盲肠黏膜的显微镜组织学评估表明，源自成像剂的荧光亮区和无荧光的暗区分别很好地表示了黏膜侧植入癌细胞的存在和不存在。这种良好的相关性表明，PNA 固定化荧光纳米球以高亲和力和特异性识别盲肠黏膜上毫米大小的肿瘤。
