Hemangioma is one of the commonest benign vascular tumors among children. Propranolol is the first-line therapeutic drug for hemangioma. However, the effects and mechanisms of propranolol in hemangioma have not been thoroughly elaborated. In this study, the effects and mechanisms of propranolol were explored using hemangioma-derived endothelial cells (HemECs). The expression of GLUT1 were determined by immunofluorescence staining. qRT-PCR assay was conducted to detect the mRNA expressions of angiopoietin-2 (Ang-2) and Tie-2. Western blot assay was carried out to measure the protein levels of Ang-2, Tie-2, protein kinase-B (Akt) and phospholyrated-Akt (p-Akt). Cell proliferation was assessed by Cell Counting Kit-8 (CCK-8) assay and Western blot of Ki67 protein level. Cell apoptosis was measured by flow cytometry analysis and Western blot of Bax and Bcl-2 levels. We found that propranolol inhibited proliferation and induced apoptosis in human umbilical vein endothelial cells (HUVECs) and HemECs. Moreover, propranolol inhibited the expressions of Ang-2 and Tie-2 in HUVECs and HemECs. Functional analysis revealed that Ang-2 attenuated the effects of propranolol on HemEC proliferation and apoptosis. Mechanistical analysis showed that propranolol inhibited the Akt pathway by regulating Ang-2 expression in HemECs. Futhermore, inhibition of the Akt pathway attenuated the effects of Ang-2 on proliferation and apoptosis in HemECs. In conclusion, propranolol inhibited proliferation and induced apoptosis of HemECs via Akt pathway by down-regulating Ang-2 expression, which contributes to our understanding on the pathogenesis of hemangioma and promotes the development of therapeutic approaches for hemangioma.

中文翻译：

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普萘洛尔通过下调Ang-2表达，通过Akt途径抑制血管瘤血管内皮细胞的增殖并诱导其凋亡。

血管瘤是儿童中最常见的良性血管肿瘤之一。普萘洛尔是血管瘤的一线治疗药物。然而，普萘洛尔在血管瘤中的作用和机制尚未得到详尽的阐述。在这项研究中，使用血管瘤来源的内皮细胞（HemECs）探索了普萘洛尔的作用及其机制。通过免疫荧光染色确定GLUT1的表达。进行qRT-PCR测定以检测血管生成素-2（Ang-2）和Tie-2的mRNA表达。进行蛋白质印迹分析以测量Ang-2，Tie-2，蛋白激酶-B（Akt）和磷酸化-Akt（p-Akt）的蛋白水平。细胞增殖通过细胞计数试剂盒8（CCK-8）分析和Ki67蛋白水平的蛋白质印迹进行评估。通过流式细胞术分析和Bax和Bcl-2水平的蛋白质印迹法测量细胞凋亡。我们发现，普萘洛尔抑制人脐静脉内皮细胞（HUVECs）和HemECs的增殖并诱导其凋亡。此外，普萘洛尔可抑制HUVEC和HemEC中Ang-2和Tie-2的表达。功能分析表明，Ang-2减弱了心得安对HemEC增殖和凋亡的影响。机理分析表明，普萘洛尔通过调节HemECs中的Ang-2表达来抑制Akt途径。此外，对Akt途径的抑制减弱了Ang-2对HemECs增殖和凋亡的影响。总之，普萘洛尔通过下调Ang-2表达来抑制HemECs的增殖并通过Akt途径诱导其凋亡，