PDGFRβ靶向性近红外荧光探针的制备及其在肺癌光学分子影像中的应用

Preparation and application of a PDGFRβ-targeted near-infrared fluorescent probe for molecular optical imaging of lung cancer

目的制备血小板衍生生长因子受体β(platelet-derived growth factor receptorβ,PDGFRβ)靶向性分子探针,并评价其用于肺癌光学分子影像的可能性。方法通过基因工程方法,利用大肠杆菌重组表达系统生产并制备PDGFRβ特异性亲和体Z-tri。利用流式细胞术分析Z-tri对体外培养细胞的结合能力,用示踪法监测Ztri在移植瘤内的细胞分布。将近红外荧光染料CF750与Z-tri偶联制备光学分子探针(CF750-)^Z-tri,并利用光学成像系统检测其对人肺癌细胞移植瘤的显像效果。结果PDGFRβ特异性亲和体Z-tri在大肠杆菌中获得大量表达,且能通过简单的亲和层析进行纯化。该蛋白体外条件下能与PDGFRβ阳性细胞结合,进入移植瘤内也主要分布于PDGFRβ强阳性细胞。近红外荧光染料CF750能够高效地与Z-tri偶联。制备的近红外荧光探针(CF750-)^Z-tri能快速、清楚地通过光学成像显示肺癌移植瘤。结论近红外光学分子探针(CF750-)^Z-tri能够用于肺癌分子影像,在利用术中导航指导肺癌组织精准切除方面有应用前景。

Objective To prepare platelet-derived growth factor receptorβ(PDGFRβ)-targeted near-infrared molecular probe and evaluate its potential in optical molecular imaging of lung cancer.Methods PDGFRβ-specific affibody Z-tri was recombinantly expressed in Escherichia coli(E.coli)and purified using affinity chromatography.In vitro cell-binding of Z-tri was analyzed by flow cytometry.Cellular distribution of Z-tri in tumor grafts was determined by protein-tracing.The molecular probe (CF750-)^Z-tri was prepared by conjugating near-infrared fluorescent dye CF750 to Z-tri.The optical images of xenografts of lung cancer were obtained by using (CF750-)^Z-tri combined with optical imaging system.Results PDGFRβ-specific affibody Z-tri was highly expressed in E.coli and purified to homogeneity.Z-tri could bind PDGFRβ-positive cells but not PDGFRβ-negative cells cultured in vitro.In the tumor xenografts of human lung cancer,intravenously injected Z-tri was predominantly distributed on cells overexpressing PDGFRβ.The near infrared fluorescent dye CF750 was efficiently conjugated to Z-tri.Optical images with high contrast of lung cancer xenografts were produced by using the near-infrared fluorescent probe (CF750-)^Z-tri combined with optical imaging system.Conclusion The nearinfrared fluorescent probe (CF750-)^Z-tri can be used for optical imaging of human lung cancer,which takes great potential in optical imaging-guided surgery of lung cancer.