Knockdown Of HMGB1 Inhibits Cell Proliferation And Induces Apoptosis In Hemangioma Via Downregulation Of AKT Pathway

Background:Infantile hemangiomas(IHs)are one of the most common soft tissue tumors in infants and young children.However,some children still need treatment because of various complications.However,there is no specific treatment for this disease,so it is of great importantance to find the new therapeutic targets.At present,most of the drugs used to treat IHs can inhibit the proliferation of vascular endothelial cells and promote cell apoptosis.The high mobility group box 1(HMGB1)as a conserved non-histone nuclear protein has been involved in a variety of biological processes of cancer,such as cell proliferation,apoptosis,angiogenesis and metastasis.As an important factor of angiogenesis,HMGB1 also can inhibit apoptosis and promote proliferation of endothelial cells.Despite the increased expression of HMGB1 in many malignant tumors,the functions and molecular mechanisms by which HMGB1 contributes to the formation of hemangioma(HA)remain unclear.Aims : To observe the effects of HMGB1 knockdown in cellproliferation and apoptosis in HA CRL-2586 EOMA cells and explore the underlying mechanism.Methods:We collected IH tissue samples which were underwent HE staining to see the difference between proliferation phases and involuting phases.Immunohistochemistry was used to detect the expression levels of HMGB1,P53,Ki67 and PCNA in different phases of human HAs.And TUNEL assay would carry out to test the apoptosis in different phases.Then we performed cell transfection to build HMGB1 knockdown cell modle.Cell function experiments including MTT,cell colony formation and flow cytometry analysis were performed to evaluate the effects of HMGB1 knockdown on cell proliferation and apoptosis in HA CRL-2586 EOMA cells.Also we used Western bolt assay to test the expression of some proteins related to cell proliferation,apoptosis as well as AKT signaling pathway,including PCNA,CyclinD1,p53,PARP,cleaved PARP,AKT and p-AKT.Results:As a consequence,we found that HMGB1 expression was significantly increased in proliferating phase HAs compared with the involuting phase HAs(P<0.01).Moreover,knockdown of HMGB1 gene in vitro suppressed EOMA cell proliferation and colony formation and induced cell apoptosis and cycle arrest at G0/G1 phase by downregulation of PCNA,CyclinD1,p-AKT and upregulation of p53.Conclusion:Taken together,our findings demonstrate that HMGB1 may be implicated in the formation of HA through upregulation of AKT pathway,and represent a potential therapeutic target for treating HA.