Expression of MEK/ERK signaling pathway in hemangioma vascular endothelial cell in vitro

Objective To observe the expression and regulation of MEK, ERK and p-ERK in hemangioma derived endothelial cells （HemECs） and examine the effects of MEK/ERK signal pathway in different phases of infantile hemangioma. Methods HemECs were isolated from freshly resected hemangioma specimens. During logarithmic phase, culture medium was changed to serum-free and cell synchronization started within 48 hours. HemECs were treated with 50 μm/L propranolol, 0. 1 ng/L estradiol for treatment group and eulture medium with serum for control group after 24 hours. Then the protein levels of MEK, ERK and p-ERK, cell cycle distribution and apoptosis were observed. Finally the relationship between apoptosis, cell cycle and protein levels of MEK, ERK and p-ERK was analyzed. Results After estradiol treatment for 24 hours, the protein levels of MEK （0. 14±0. 01）,ERK1/2 （1.36 ± 0. 11/0. 52 ± 0. 10）, p-ERK1/2（0, 12 ± 0. 03/0. 85 ± 0. 10） were higher than those of control group MEK（0. 08 ± 0. 00）, ERK1/2 （1. 16 ± 0. 06/0. 29 ± 0. 04） and p-ERK1/2 （0. 06 ± 0. 02/0. 42 ± 0. 08）. And there were significant differences （t = 10. 01,2. 86/3. 45, 3. 57/5.95, P〈0. 05）. The total ratio of cells in Go/Gt phase （90. 52 ± 1.28） % was lower than that of control group （94. 02 ± 0. 85） %. And there were significant differences （t = - 3. 98, P〈0. 05）. The total ratio of apoptosis cells （0. 70 ± 0. 10）% declined compared to control group （1.77 ± 0. 21）%. And the difference was statistically significant （t = - 8. 00, P〈0. 05）. After with a 24-hour treatment of propranolol, the protein levels of MEK （0. 06 ± 0. 01）, ERK1/2（0. 87 ± 0. 05/0. 14 ± 0. 01） and p-ERK1/2 （0. 02 ± 0. 01/0. 11 ± 0. 05） were lower than those of control group. And there was significant difference（t = - 2. 88, - 6. 79/- 6. 20, - 3.96/- 5.74, P〈0. 05）. Cell cycle were arrested in G0/G1 phase. Compared to control group, propranolol group （96. 42 ± 1. 16）% was higher than control group. And there was significant difference（t = - 2. 89,P±0. 05）. The total ratio of apoptotic cells （2. 87 ± 0. 57） % increased versus control group. And the difference was statistically significant （t = 3. 14,P〈0. 05）. Conelus｜ons MEK/ERK pathway plays an important role in G0/G1 phase arrest and apoptosis of hemangioma vascular endothelial cells in vitro. Estradiol and propranolol may regulate the proliferation and apoptosis of HemECs through MEK/ERK signaling pathway. Key words: Hemangioma;  Endothelium, vascular;  Gene expression regulation