RMSB Center, Université de Bordeaux, Bordeaux Cedex, France.
NMR Biomed. 2010 Jan;23(1):88-96. doi: 10.1002/nbm.1434.
In gene therapy against glioma, targeting tumoral tissue is not an easy task. We used the tumor infiltrating property of microglia in this study. These cells are well adapted to this therapy since they can phagocyte nanoparticles and allow their visualization by MRI. Indeed, while many studies have used transfected microglia containing a suicide gene and other internalized nanoparticles to visualize microglia, none have combined both approaches during gene therapy. Microglia cells were transfected with the TK-GFP gene under the control of the HSP(70) promoter. First, the possible cellular stress induced by nanoparticle internalization was checked to avoid a non-specific activation of the suicide gene. Then, MR images were obtained on tubes containing microglia loaded with superparamagnetic nanoparticles (VUSPIO) to characterize their MR properties, as well as their potential to track cells in vivo. VUSPIO were efficiently internalized by microglia, were found non-toxic and their internalization did not induce any cellular stress. VUSPIO relaxivity r(2) was 224 mM(-1).s(-1). Such results could generate a very high contrast between loaded and unloaded cells on T(2)-weighted images. The intracellular presence of VUSPIO does not prevent suicide gene activity, since TK is expressed in vitro and functional in vivo. It allows MRI detection of gene modified macrophages during cell therapy strategies.
在胶质母细胞瘤的基因治疗中，靶向肿瘤组织并非易事。在本研究中，我们利用了小胶质细胞的肿瘤浸润特性。这些细胞非常适合这种治疗方法，因为它们可以吞噬纳米颗粒，并通过 MRI 进行可视化。事实上，尽管许多研究已经使用转染了含有自杀基因的小胶质细胞和其他内化的纳米颗粒来可视化小胶质细胞，但在基因治疗中没有将这两种方法结合起来。小胶质细胞在 HSP(70)启动子的控制下转染 TK-GFP 基因。首先，检查纳米颗粒内化可能引起的细胞应激，以避免自杀基因的非特异性激活。然后，在含有负载超顺磁纳米颗粒 (VUSPIO) 的小胶质细胞的管中获得 MR 图像，以表征其 MR 特性以及它们在体内追踪细胞的潜力。VUSPIO 被小胶质细胞有效内化，被发现无毒，其内化不会引起任何细胞应激。VUSPIO 的弛豫率 r(2)为 224 mM(-1).s(-1)。在 T(2)加权图像上，负载和未负载细胞之间可能会产生非常高的对比度。VUSPIO 的细胞内存在不会阻止自杀基因的活性，因为 TK 在体外表达并在体内具有功能。它允许在细胞治疗策略中对基因修饰的巨噬细胞进行 MRI 检测。
