Gottschalk S, Cristiano R J, Smith L C, Woo S L
Howard Hughes Medical Institute, Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
Gene Ther. 1994 May;1(3):185-91.
We have used a particular folate receptor, which is overexpressed in tumor cells, for targeted DNA delivery into these cell types. This folate receptor internalizes folate through caveolae by a process named potocytosis, which is distinct from endocytosis, through clathrin-coated pits. When folate conjugated to poly-L-lysine was used to deliver the E. coli beta-galactosidase gene into tumor cells overexpressing the folate receptor, only low levels of beta-galactosidase activity were detectable. When a replication-defective adenovirus was coincubated with the DNA/folate complexes, 20 to 30% of the cells stained blue with X-gal and a 1000-fold increase of beta-galactosidase activity was observed. Thus, for high efficient DNA delivery and gene expression via the caveolae system, a potosomal disruption agent is needed. Furthermore, folate-mediated DNA delivery is restricted to tumor cells that highly overexpress the folate receptor, which will permit future development of tumor cell-specific delivery of toxic genes for cancer gene therapy.
我们使用了一种在肿瘤细胞中过度表达的特定叶酸受体，用于将靶向DNA递送至这些细胞类型中。这种叶酸受体通过名为胞饮作用的过程，经小窝将叶酸内化，这一过程与通过网格蛋白包被小窝的内吞作用不同。当使用与聚-L-赖氨酸偶联的叶酸将大肠杆菌β-半乳糖苷酶基因递送至过度表达叶酸受体的肿瘤细胞时，仅能检测到低水平的β-半乳糖苷酶活性。当将复制缺陷型腺病毒与DNA/叶酸复合物共同孵育时，20%至30%的细胞用X-gal染色呈蓝色，并且观察到β-半乳糖苷酶活性增加了1000倍。因此，为了通过小窝系统高效递送DNA和进行基因表达，需要一种破坏胞饮体的试剂。此外，叶酸介导的DNA递送仅限于高度过度表达叶酸受体的肿瘤细胞，这将为未来癌症基因治疗中肿瘤细胞特异性递送毒性基因的发展提供可能。
