Sarkar R, Finniss S, Dickinson C J, Stanley J C
Department of Surgery, University of Michigan Medical Center, Ann Arbor, USA.
J Vasc Surg. 1998 May;27(5):955-62. doi: 10.1016/s0741-5214(98)70278-2.
The antiproliferative and antisecretory effects of somatostatin have many potential uses in the clinical setting. Retroviral gene transfer of somatostatin to endothelium is a potential means of local delivery of this peptide to specific vascular beds. This investigation was designed to determine whether transduced endothelial cells (ECs) could produce and post-translationally process somatostatin.
Cultured canine venous, rat aortic, and rat microvascular ECs were transfected with retroviruses containing a human somatostatin cDNA or a control beta-galactosidase gene. Total and isoform somatostatin production and uniformity of beta-galactosidase expression were analyzed, as were the effects of somatostatin production on EC proliferation.
Somatostatin-transduced canine venous ECs, but not rat ECs, produced approximately 10 times as much total somatostatin as did control-transfected ECs (450 +/- 32 vs 49 +/- 10 pmol/L, p < 0.05). The predominant isoform of somatostatin produced was somatostatin-14. Production of somatostatin was stable with passage and did not impair the growth of canine ECs. The failure of rat ECs to produce somatostatin correlated with nonuniform expression of beta-galactosidase, suggesting that promoter silencing was responsible for failure of transgene expression.
Retroviral gene transfer of somatostatin to canine ECs results in the production of physiologically relevant concentrations of biologically active somatostatin. Significant species differences exist in EC production of somatostatin, with promoter silencing being a potential mechanism of failure of gene expression. Gene therapy strategies using retroviral transfer of somatostatin to ECs may allow somatostatin delivery to focal areas of the vasculature.
生长抑素的抗增殖和抗分泌作用在临床中有许多潜在用途。将生长抑素通过逆转录病毒基因转移至内皮细胞是将该肽局部递送至特定血管床的一种潜在方法。本研究旨在确定转导的内皮细胞（ECs）是否能够产生生长抑素并进行翻译后加工。
用含有人生长抑素cDNA或对照β-半乳糖苷酶基因的逆转录病毒转染培养的犬静脉内皮细胞、大鼠主动脉内皮细胞和大鼠微血管内皮细胞。分析了生长抑素的总量和异构体产生情况以及β-半乳糖苷酶表达的均匀性，还分析了生长抑素产生对EC增殖的影响。
转导生长抑素的犬静脉内皮细胞而非大鼠内皮细胞产生的生长抑素总量约为对照转染内皮细胞的10倍（450±32对49±10 pmol/L，p<0.05）。产生的生长抑素的主要异构体是生长抑素-14。生长抑素的产生随传代稳定，且不损害犬内皮细胞的生长。大鼠内皮细胞未能产生生长抑素与β-半乳糖苷酶表达不均匀相关，提示启动子沉默是转基因表达失败的原因。
将生长抑素通过逆转录病毒基因转移至犬内皮细胞可导致产生生理相关浓度的生物活性生长抑素。内皮细胞产生生长抑素存在显著的种属差异，启动子沉默是基因表达失败的潜在机制。利用逆转录病毒将生长抑素转移至内皮细胞的基因治疗策略可能使生长抑素能够递送至脉管系统的局部区域。
