Høgset A, Prasmickaite L, Engesaeter B O, Hellum M, Selbo P K, Olsen V M, Maelandsmo G M, Berg K
PCI Biotech AS, Hoffsvn. 48, N-0377 Oslo, Norway.
Curr Gene Ther. 2003 Apr;3(2):89-112. doi: 10.2174/1566523034578438.
Numerous gene therapy vectors, both viral and non-viral, are taken into the cell by endocytosis, and for efficient gene delivery the therapeutic genes carried by such vectors have to escape from endocytic vesicles so that the genes can further be translocated to the nucleus. Since endosomal escape is often an inefficient process, release of the transgene from endosomes represents one of the most important barriers for gene transfer by many such vectors. To improve endosomal escape we have developed a new technology, named photochemical internalisation (PCI). In this technology photochemical reactions are initiated by photosensitising compounds localised in endocytic vesicles, inducing rupture of these vesicles upon light exposure. The technology constitutes an efficient light-inducible gene transfer method in vitro, where light-induced increases in transfection or viral transduction of more than 100 and 30 times can be observed, respectively. The method can potentially be developed into a site-specific method for gene delivery in vivo. This article will review the background for the PCI technology, and several aspects of PCI induced gene delivery with synthetic and viral vectors will be discussed. Among these are: (i) The efficiency of the technology with different gene therapy vectors; (ii) use of PCI with targeted vectors; (iii) the timing of DNA delivery relative to the photochemical treatment. The prospects of using the technology for site-specific gene delivery in vivo will be thoroughly discussed, with special emphasis on the possibilities for clinical use. In this context our in vivo experience with the PCI technology as well as the clinical experience with photodynamic therapy will be treated, as this is highly relevant for the clinical use of PCI-mediated gene delivery. The use of photochemical treatments as a tool for understanding the more general mechanisms of transfection will also be discussed.
许多基因治疗载体，包括病毒载体和非病毒载体，都是通过内吞作用进入细胞的。为了实现高效的基因传递，此类载体携带的治疗性基因必须从内吞小泡中逃逸出来，以便基因能够进一步转运至细胞核。由于内体逃逸往往是一个低效的过程，因此从内体中释放转基因是许多此类载体进行基因转移的最重要障碍之一。为了改善内体逃逸，我们开发了一种名为光化学内化（PCI）的新技术。在这项技术中，光化学反应由定位在内吞小泡中的光敏化合物引发，光照后诱导这些小泡破裂。该技术在体外构成了一种高效的光诱导基因传递方法，分别可以观察到光诱导的转染或病毒转导增加100倍和30倍以上。该方法有可能发展成为一种体内基因传递的位点特异性方法。本文将综述PCI技术的背景，并讨论PCI介导的合成载体和病毒载体基因传递的几个方面。其中包括：（i）该技术对不同基因治疗载体的效率；（ii）将PCI与靶向载体结合使用；（iii）DNA传递相对于光化学处理的时间。将深入讨论该技术用于体内位点特异性基因传递的前景，特别强调临床应用的可能性。在此背景下，我们将介绍PCI技术的体内实验经验以及光动力疗法的临床经验，因为这与PCI介导的基因传递的临床应用高度相关。还将讨论使用光化学处理作为理解更一般转染机制的工具。
