Cancer Research UK Centre, Somers Building, Tremona Road, Southampton, SO16 6YD, UK.
J Clin Endocrinol Metab. 2013 Dec;98(12):E1918-26. doi: 10.1210/jc.2013-2602. Epub 2013 Oct 23.
Targeted secretion inhibitors (TSIs), a new class of recombinant biotherapeutic proteins engineered from botulinum toxin, represent a novel approach for treating diseases with excess secretion. They inhibit hormone secretion from targeted cell types through cleavage of SNARE (soluble N-ethylmaleimide-sensitive factor-activating protein receptor) proteins. qGHRH-LH(N)/D is a TSI targeting pituitary somatotroph through binding to the GHRH-receptor and cleavage of the vesicle-associated membrane protein (VAMP) family of SNARE proteins.
Our objective was to study SNARE protein expression in pituitary adenomas and to inhibit GH secretion from somatotropinomas using qGHRH-LH(N)/D.
We analyzed human pituitary adenoma analysis for SNARE expression and response to qGHRH-LH(N)/D treatment.
The study was conducted in University Hospitals.
We used pituitary adenoma samples from 25 acromegaly and 47 nonfunctioning pituitary adenoma patients.
Vesicle-SNARE (VAMP1-3), target-SNARE (syntaxin1, SNAP-23, and SNAP-25), and GHRH-receptor detection with RT-qPCR, immunocytochemistry, and immunoblotting. Assessment of TSI catalytic activity on VAMPs and release of GH from adenoma cells.
SNARE proteins were variably expressed in pituitary samples. In vitro evidence using recombinant GFP-VAMP2&3 or pituitary adenoma lysates suggested sufficient catalytic activity of qGHRH-LH(N)/D to degrade VAMPs, but was unable to inhibit GH secretion in somatotropinoma cell cultures.
SNARE proteins are present in human pituitary somatotroph adenomas that can be targeted by TSIs to inhibit GH secretion. qGHRH-LH(N)/D was unable to inhibit GH secretion from human somatotroph adenoma cells. Further studies are required to understand how the SNARE proteins drive GH secretion in human somatotrophs to allow the development of novel TSIs with a potential therapeutic benefit.
靶向分泌抑制剂（TSI）是一类新型的重组生物治疗蛋白，由肉毒杆菌毒素工程化而来，代表了一种治疗过度分泌相关疾病的新方法。它们通过切割 SNARE（可溶性 N-乙基马来酰亚胺敏感因子激活蛋白受体）蛋白来抑制靶向细胞类型的激素分泌。qGHRH-LH（N）/D 是一种通过与 GHRH 受体结合并切割囊泡相关膜蛋白（VAMP）家族 SNARE 蛋白来靶向垂体生长激素细胞的 TSI。
我们的目的是研究垂体腺瘤中 SNARE 蛋白的表达，并使用 qGHRH-LH（N）/D 抑制生长激素细胞瘤的 GH 分泌。
我们分析了人类垂体腺瘤中 SNARE 的表达，并研究了 qGHRH-LH（N）/D 治疗的反应。
研究在大学附属医院进行。
我们使用了 25 例肢端肥大症和 47 例无功能垂体腺瘤患者的垂体腺瘤样本。
用 RT-qPCR、免疫细胞化学和免疫印迹法检测囊泡-SNARE（VAMP1-3）、靶-SNARE（突触素 1、SNAP-23 和 SNAP-25）和 GHRH 受体。评估 TSI 对 VAMPs 的催化活性以及 GH 从腺瘤细胞中的释放。
SNARE 蛋白在人类垂体生长激素细胞腺瘤中表达不同。使用重组 GFP-VAMP2&3 或垂体腺瘤裂解物的体外证据表明，qGHRH-LH（N）/D 具有足够的催化活性来降解 VAMPs，但不能抑制生长激素细胞瘤细胞培养物中的 GH 分泌。
SNARE 蛋白存在于人类垂体生长激素细胞瘤中，可以被 TSI 靶向以抑制 GH 分泌。qGHRH-LH（N）/D 不能抑制人类生长激素细胞瘤细胞的 GH 分泌。需要进一步研究以了解 SNARE 蛋白如何驱动人类生长激素细胞中的 GH 分泌，从而开发具有潜在治疗益处的新型 TSI。
