Depletion of Serotonin and Selective Inhibition of 2B Receptor Suppressed Tumor Angiogenesis by Inhibiting Endothelial Nitric Oxide Synthase and Extracellular Signal-Regulated Kinase 1/2 Phosphorylation
Depletion of Serotonin and Selective Inhibition of 2B Receptor Suppressed Tumor Angiogenesis by Inhibiting Endothelial Nitric Oxide Synthase and Extracellular Signal-Regulated Kinase 1/2 Phosphorylation
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DOI：
10.1593/neo.81630
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发表时间：
2009-04-01
期刊：
影响因子：
4.8
通讯作者：
Arai, Hiroyuki
中科院分区：
文献类型：
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作者：
Asada, Masanori;Ebihara, Satoru;Arai, Hiroyuki
5-羟色胺(5-HT)对肿瘤生长的影响是不一致的。我们利用5-羟色胺转运体基因敲除(5-HTT-/-)小鼠来研究5-羟色胺水平降低是否影响肿瘤生长，这表明5-羟色胺缺乏。当癌细胞同时注射到5-HTT-/-和5-HTT+/+小鼠的皮下时，5-HTT-/-小鼠的肿瘤生长明显减弱。携带肿瘤的5-HTT-/-小鼠血液、前脑和肿瘤中的5-羟色胺水平显著低于其5-HTT+/+小鼠。然而，5-羟色胺在体外并不促进癌细胞的增殖。当我们将5-HTT抑制剂应用于携带肿瘤的野生小鼠时，它们并没有抑制肿瘤的生长。与5-HTT+/+小鼠相比，5-HTT-/-小鼠肿瘤内皮型一氧化氮合酶(ENOS)表达减少。5-羟色胺(1-50 mU M)刺激人脐静脉内皮细胞(HUVEC)可诱导eNOS表达，且呈浓度依赖性。当我们使用高通量磷酸特异性抗体平台检测多个信号通路的激活时，5-羟色胺刺激HUVEC中的细胞外信号调节激酶1/2(ERK1/2)。此外，我们还发现，生理水平的5-羟色胺可诱导HUVEC ERK1/2和eNOS的磷酸化。人脐静脉内皮细胞同时表达5-HT2B和5-HT2C受体。特异性5-HT2B受体阻断剂SB204741可阻断5-羟色胺诱导的ERK1/2和eNOS的磷酸化，而特异性5-HT2C受体阻断剂RS102221则不能阻断5-羟色胺诱导的内皮细胞ERK1/2和eNOS的磷酸化。SB204741可降低肿瘤微血管密度，抑制HUVEC的体外增殖。这些结果提示，5-羟色胺和5-羟色胺受体的调节，特别是5-HT2B受体的调节，可能是肿瘤治疗的一种治疗策略。
The effects of serotonin (5-HT) on tumor growth are inconsistent. We investigated whether a decreased level of 5-HT affected tumor growth using 5-HT transporter knockout (5-HTT-/-) mice, which showed 5-HT depletion. When cancer cells were injected subcutaneously into both 5-HTT-/- and 5-HTT+/+ mice, the tumor growth was markedly attenuated in 5-HTT-/- mice. Serotonin levels in the blood, forebrain, and tumors of 5-HTT-/- mice bearing tumors were significantly smaller than those of their 5-HTT+/+ littermates. However, 5-HT did not increase cancer cells' proliferation in vitro. When we applied 5-HTT inhibitors to the wild mice bearing tumors, they did not inhibit tumor growth. The endothelial nitric oxide synthase (eNOS) expressions in tumors were reduced in 5-HTT-/- mice compared with 5-HTT+/+ mice. Stimulations with 5-HT (1-50 mu M) induced eNOS expressions in human umbilical vein endothelial cell (HUVEC) in a concentration-dependent manner. When we measured activations of multiple signaling pathways by using a high-throughput phosphospecific antibodies platform, 5-HT stimulated the extracellular signal regulated kinase 1/2 (ERK1/2) in HUVEC. Moreover, we found that the physiological level of 5-HT induced phosphorylation of both ERK1/2 and eNOS in HUVEC. Human umbilical vein endothelial cell expressed both 5-HT2B and 5-HT2C receptors. SB204741, a specific 5-HT2B receptor inhibitor, blocked 5-HT-induced ERK1/2 and eNOS phosphorylations, whereas RS102221, a specific 5-HT2C receptor inhibitor, did not in HUVEC. SB204741 reduced microvessel density in tumors and inhibited the proliferation of HUVEC in vitro. These results suggest that regulation of 5-HT and 5-HT receptors, especially the 5-HT2B receptor, may serve as a therapeutic strategy in cancer therapy.