Graff L, Castrop F, Bauer M, Höfler H, Gratzl M
Anatomisches Institut, Universität München, Germany.
Cancer Res. 2001 Mar 1;61(5):2138-44.
Vesicular monoamine transporters (VMATs) are a prerequisite for the uptake of biogenic amines into intracellular storage organelles, whereas soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs; such as SNAP-25 and syntaxin1) are essential for exocytosis of biogenic amines by neurons and endocrine cells. In this study, we examined whether these proteins exist in high-grade malignant small cell lung carcinomas (SCLCs), large cell carcinomas, adenocarcinomas, and squamous cell carcinomas of the lung. We analyzed two established human SCLC cell lines, one adenocarcinoma cell line, paraffin-embedded tumors (SCLC, n = 25; large cell carcinoma, n = 10; adenocarcinoma, n = 10; squamous cell carcinoma, n = 10), and snap-frozen SCLC samples (n = 2). Using immunocytochemistry, Western blotting, Northern blotting, RT-PCR, and sequencing, we identified VMAT1, VMAT2, SNAP-25, and syntaxin1 in cultured SCLC cells. Immunohistochemistry carried out on paraffin sections revealed that all SCLC tumors express VMAT1, VMAT2, SNAP-25, and syntaxin1. The presence of SNAP-25 and syntaxin1 in SCLC was confirmed by RT-PCR performed with material extracted from paraffin sections. Western blot analysis and RT-PCR carried out with snap-frozen SCLC tumors revealed the presence of SNAREs and VMATs. Immunohistochemistry showed that non-SCLC tumors were negative for SNAREs and VMATs, with the exception of immunostaining for SNAP-25 and syntaxin1 in 3 of 10 adenocarcinomas. Our findings indicate that SCLC cells are endowed with transporters necessary for intracellular storage of biogenic amines and with proteins required for exocytosis of secretory products. These proteins may be used as markers of differentiation of human lung tumors. Moreover, the presence of VMATs provides the basis for a diagnostic application of biogenic amine-derived tracers in positron emission tomography of SCLC tumors.
囊泡单胺转运体（VMATs）是生物胺摄取到细胞内储存细胞器的前提条件，而可溶性N - 乙基马来酰亚胺敏感因子附着蛋白受体（SNAREs；如SNAP - 25和 syntaxin1）对于神经元和内分泌细胞释放生物胺至关重要。在本研究中，我们检测了这些蛋白是否存在于高级别恶性小细胞肺癌（SCLCs）、大细胞癌、腺癌和肺鳞状细胞癌中。我们分析了两种已建立的人SCLC细胞系、一种腺癌细胞系、石蜡包埋肿瘤（SCLC，n = 25；大细胞癌，n = 10；腺癌，n = 10；鳞状细胞癌，n = 10）以及速冻SCLC样本（n = 2）。使用免疫细胞化学、蛋白质印迹法、Northern印迹法、逆转录 - 聚合酶链反应（RT - PCR）和测序，我们在培养的SCLC细胞中鉴定出VMAT1、VMAT2、SNAP - 25和syntaxin1。对石蜡切片进行的免疫组织化学显示，所有SCLC肿瘤均表达VMAT1、VMAT2、SNAP - 25和syntaxin1。用从石蜡切片中提取的材料进行RT - PCR证实了SCLC中存在SNAP - 25和syntaxin1。对速冻SCLC肿瘤进行的蛋白质印迹分析和RT - PCR显示存在SNAREs和VMATs。免疫组织化学表明，非SCLC肿瘤对SNAREs和VMATs呈阴性，但10例腺癌中有3例对SNAP - 25和syntaxin1呈免疫染色阳性。我们的研究结果表明，SCLC细胞具有生物胺细胞内储存所需的转运体以及分泌产物胞吐所需的蛋白质。这些蛋白可作为人肺肿瘤分化的标志物。此外，VMATs的存在为生物胺衍生示踪剂在SCLC肿瘤正电子发射断层扫描中的诊断应用提供了基础。
