Sato Kazuhide, Gorka Alexander P, Nagaya Tadanobu, Michie Megan S, Nani Roger R, Nakamura Yuko, Coble Vince L, Vasalatiy Olga V, Swenson Rolf E, Choyke Peter L, Schnermann Martin J, Kobayashi Hisataka
Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health , Rockville, Maryland 20850, United States.
Bioconjug Chem. 2016 Feb 17;27(2):404-13. doi: 10.1021/acs.bioconjchem.5b00492. Epub 2015 Oct 23.
Near-infrared (NIR) fluorophores have several advantages over visible-light fluorophores, including superior light penetration in tissue and lower autofluorescence. We recently demonstrated that a new class of NIR cyanine dyes containing a novel C4'-O-alkyl linker exhibit greater chemical stability and excellent optical properties relative to existing C4'-O-aryl variants. We synthesized two NIR cyanine dyes with the same core structure but different indolenine substituents: FNIR-774 bearing four sulfonate groups and FNIR-Z-759 bearing a combination of two sulfonates and two quaternary ammonium cations, resulting in an anionic (-3) or monocationic (+1) charge, respectively. In this study, we compare the in vitro and in vivo optical imaging properties of monoclonal antibody (mAb) conjugates of FNIR-774 and FNIR-Z-759 with panitumumab (pan) at antibody-to-dye ratios of 1:2 or 1:5. Conjugates of both dyes demonstrated similar quenching capacity, stability, and brightness in target cells in vitro. However, FNIR-Z-759 conjugates showed significantly lower background in mice, resulting in higher tumor-to-background ratio. Thus, FNIR-Z-759 conjugates appear to have superior in vivo imaging characteristics compared with FNIR-774 conjugates, especially in the abdominal region, regardless of the dye-mAb ratio. These results suggest that zwitterionic cyanine dyes are a promising class of fluorophores for improving in vivo optical imaging with antibody-NIR dye conjugates.
近红外（NIR）荧光团相对于可见光荧光团具有多个优势，包括在组织中具有更好的光穿透性以及更低的自发荧光。我们最近证明，一类含有新型C4'-O-烷基连接基的新型近红外花青染料相对于现有的C4'-O-芳基变体表现出更高的化学稳定性和优异的光学性质。我们合成了两种具有相同核心结构但吲哚啉取代基不同的近红外花青染料：带有四个磺酸根基团的FNIR-774和带有两个磺酸根和两个季铵阳离子组合的FNIR-Z-759，分别产生阴离子（-3）或单阳离子（+1）电荷。在本研究中，我们比较了FNIR-774和FNIR-Z-759与帕尼单抗（pan）的单克隆抗体（mAb）缀合物在抗体与染料比例为1:2或1:5时的体外和体内光学成像特性。两种染料的缀合物在体外靶细胞中表现出相似的猝灭能力、稳定性和亮度。然而，FNIR-Z-759缀合物在小鼠体内的背景显著更低，从而导致更高的肿瘤与背景比值。因此，无论染料与单克隆抗体的比例如何，FNIR-Z-759缀合物与FNIR-774缀合物相比似乎具有更优异的体内成像特性，尤其是在腹部区域。这些结果表明，两性离子花青染料是一类有前景的荧光团，可用于改善抗体 - 近红外染料缀合物的体内光学成像。
