Knockdown of HMGB1 inhibits cell proliferation and induces apoptosis in hemangioma via downregulation of AKT pathway.

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. 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. In the present study, immunohistochemistry was used to detect the expression levels of HMGB1 in different phases of human HAs. 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. As a consequence, we found that HMGB1 expression was significantly increased in proliferating phase HAs compared with the involuting phase HAs and normal skin tissues (P less than 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 and cleaved PARP. 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.