The Effect Of MTOR/p70S6K Signal Pathways In Children Hemangioma

Objective To study the effect of mTOR/p70S6K signal pathways in the different phases of children hemangioma.Methods1.31 hemangioma specimens were classified by Mulliken's classification and the expres-sion of proliferating cell nuclear antigen (PCNA).The expressions of PCNA, mTOR,p70S6K-a were detected by immunohistochemistry method.2. The hemangioma vascular endothelial cells which came from the sterile hemangioma were cultured by using the tissue culture method.The hemangioma vascular endothelial cell was identified by the immunohistochemistry technique observing the expression of the FactorⅧantigen which only existed in endothelial cells. Synchronized cultured endothelial cells,mTOR and p70S6K-a of them were detected by Western blot mean-while cell cycle were examined by flow cytometry technique,and then analysis of mTOR,p70S6K-a in expression level of hemangioma vascular endothelial cell cycle and apoptosis related.3. Repamycin was added to observed the effects on the expressions of mTOR,p70S6K-αand the cell cycle distribution with the hemangioma vascular endothelial cell.Results1.31 hemagioma specimens were classified as 18 hemagioma proliferating phase speci-mens,13 hemagioma involuting phase specimens.In the hemagioma proliferating ph-ase specimens, the IOD of mTOR,p70S6K-a expressed were 6336.48±1655.89, 588.72±223.87 respectively. In the hemagioma involuting phase specimens, the IOD of mTOR, p70S6K-a expressed were 846.22±297.09,3235.64±947.77 respectively. In the hemagioma proliferating phase specimens,the IOD of p70S6K-a expressed were obviously lower than the IOD in the proliferating phase specimens (P<0.01).In the hemagioma proliferating phase specimens,the IOD of mTOR expressed was obviously higher than the IOD in the involuting phase specimens (P<0.01).2. The hemangioma vascular endothelial cells migrated from the tissue to the postcultural after four days, only a small number of cells spread after one week adherent growth, growth and division after two weeks, three weeks after the cells began to grow fast, and around, the cells covered the bottom plate.Inverted phase contrast microscope and found that the isolated endothelial cultured epithelial cell morphology. Cultured cells of FactorⅧrelated antigen was positive.3. When higher expression level of mTOR protein, lower of p70S6K-a, the cells in G0/G1 phase were less (55.95±4.38)%,when mTOR protein expression level decreased,and p70S6K-a protein improved,cells in the G0/G1 phase increased (77.86±8.18)%.4. After rapamycin acts on the cultured hemangioma vascular endothelial cells for 24 hour, inducing G1 cell cycle arrest (P<0.01); the expression of mTOR protein decreased(P <0.01),the expression of p70S6K-αprotein rised(P<0.01).Conclusions1. mTOR high expressed in proliferation may lead to the phosphorylation of p70S6k, promot hemangiomas vascular endothelial cells from G0/G1 into S phase and show a rapid proliferation state. under the action of some mechanism, the expression of mTOR was decreased,which inhibited p70S6k phosphorylation,the cell cycle arrestted in G0/G1 phase, thus accelerated the apoptosis of hemangiomas vascular endothelial cells and the hemangioma vascular tumors demonstrated natural regres sion trend.2. In cultured vascular endothelial cells,the high expression of mTOR led to the phosphory-lation of p70S6k, promot hemangioma vascular endothelial cells from G0/G1 into S phase, the proliferation of endothelial cells was rapid,on the contrary.The expression of mTOR decreased, inhibited the phosphorylation of p70S6K,cell cycle was arrest in G1/G2 phase, promoting the apoptosis of vascular endothelial cells.3. Rapamycin might remain the cultured hemangioma vascular endothelial cells in the G0/G1 phase.