Role of Thrombospondin-1 and Nuclear Factor-κB Signaling Pathways in Antiangiogenesis of Infantile Hemangioma

Propranolol is the first-line drug for treatment of infantile hemangioma. However, its mechanism of action remains unclear. Nuclear factor-κB is highly expressed in tumors, directly or indirectly promoting angiogenesis. Thrombospondin-1 is the most important antiangiogenesis protein in vivo. These proteins mediate signaling pathways, probably playing an important role in hemangioma treatment. This study explored the synergistic regulation of thrombospondin-1 and nuclear factor-κB signaling pathways in the treatment of hemangioma with propranolol. The hemangioma-derived endothelial cells were sorted out from the specimens of proliferative hemangioma by flow cytometry. Furthermore, a BALB/c nude mouse hemangioma model was established. Viability and proliferation of hemangioma-derived endothelial cells and the role of thrombospondin-1 and nuclear factor-κB signaling pathways were observed after propranolol administration in vitro and in vivo. The expression of thrombospondin-1 and its receptor CD36 in hemangioma-derived endothelial cells gradually increased with the increase in propranolol concentration, whereas the expression of nuclear factor-κBp65, phosphorylated inhibitor of κB alpha (p-IκBα), and phosphorylated inhibitor of nuclear factor-κB kinase beta (p-IκKβ) weakened gradually (p < 0.05). In vivo, the tumors shrank gradually after propranolol treatment, with an increase in thrombospondin-1 and CD36 and a decrease in nuclear factor-κBp65, p-IκBα, and p-IκKβ (p < 0.05). Glucocorticoid improved the antiangiogenesis mediated by thrombospondin-1/CD36 and inhibited the angiogenesis mediated by nuclear factor-κB/IκB (p < 0.05). Negative regulation occurred between the two signaling pathways. The treatment of infantile hemangioma with propranolol is promising to promote thrombospondin-1-mediated antiangiogenesis and to block nuclear factor-κB-mediated angiogenesis.