Charité, Universitätsmedizin Berlin, Campus Virchow-Clinic, Department of Ophthalmology, Berlin, Germany.
Cell Signal. 2012 Jan;24(1):233-46. doi: 10.1016/j.cellsig.2011.09.005. Epub 2011 Sep 14.
Transient receptor potential channels (TRPs) regulate tumor growth via calcium-dependent mechanisms. The (thermosensitive) capsaicin receptor TRPV1 is overexpressed in numerous highly aggressive cancers. TRPV1 has potent antiproliferative activity and is therefore potentially applicable in targeted therapy of malignancies. Recently, we characterized TRPM8 functions in pancreatic neuroendocrine tumors (NETs), however, the role of TRPV1 is unknown. Here, we studied the expression and the role of TRPV1 in regulating intracellular Ca(2+) and chromogranin A (CgA) secretion in pancreatic NET BON-1 cell line and in primary NET cells (prNET). TRPV1 expression was detected by RT-PCR, Western blot and immunofluorescence. Intracellular free Ca(2+) (Ca(2+)) was measured by fura-2; TRPV1 channel currents by the planar patch-clamp technique. Nonselective cation currents were analyzed by a color-coded plot method and CgA secretion by ELISA. Pancreatic BON-1 cells and NETs express TRPV1. Pharmacological blockade of TRPs by La(3+) (100 μM) or by ruthenium-red (RuR) or by capsazepine (CPZ) (both at 10 μM) suppressed the capsaicin (CAP)- or heat-stimulated increase of Ca(2+) in NET cells. CAP (20 μM) also increased nonselective cation channel currents in BON-1 cells. Furthermore, CAP (10 μM) stimulated CgA secretion, which was inhibited by CPZ or by RuR (both 10 μM). La(3+) potently reduced both stimulated and the basal CgA secretion. Our study shows for the first time that TRPV1 is expressed in pancreatic NETs. Activation of TRPV1 translates into changes of intracellular Ca(2+), a known mechanism triggering the secretion of CgA. The clinical relevance of TRPV1 activation in NETs requires further investigations.
瞬时受体电位通道 (TRPs) 通过钙依赖性机制调节肿瘤生长。许多高度侵袭性癌症中都过度表达了（热敏）辣椒素受体 TRPV1。TRPV1 具有很强的抗增殖活性，因此在恶性肿瘤的靶向治疗中具有潜在的应用价值。最近，我们研究了 TRPM8 在胰腺神经内分泌肿瘤 (NETs) 中的功能，但 TRPV1 的作用尚不清楚。在这里，我们研究了 TRPV1 在调节胰腺 NET BON-1 细胞系和原代 NET 细胞 (prNET) 细胞内 Ca(2+) 和嗜铬粒蛋白 A (CgA) 分泌中的表达和作用。通过 RT-PCR、Western blot 和免疫荧光检测 TRPV1 的表达。通过 fura-2 测量细胞内游离 Ca(2+) (Ca(2+))；通过平面膜片钳技术测量 TRPV1 通道电流。通过彩色编码图方法分析非选择性阳离子电流，通过 ELISA 分析 CgA 分泌。胰腺 BON-1 细胞和 NET 表达 TRPV1。用 La(3+)（100 μM）或钌红 (RuR) 或辣椒素 (CPZ)（均为 10 μM）阻断 TRP 抑制 NET 细胞中 CAP 或热刺激引起的 Ca(2+)增加。CAP（20 μM）还增加了 BON-1 细胞中非选择性阳离子通道电流。此外，CAP（10 μM）刺激 CgA 分泌，CPZ 或 RuR（均为 10 μM）抑制 CgA 分泌。La(3+) 强烈抑制刺激和基础 CgA 分泌。我们的研究首次表明，TRPV1 在胰腺 NET 中表达。TRPV1 的激活转化为细胞内 Ca(2+) 的变化，这是触发 CgA 分泌的已知机制。TRPV1 在 NETs 中的激活的临床相关性需要进一步研究。
