The U251 and U-87MG cells were cultured at 37 C in an environment with saturated humidity and 5% CO2in the Eagles minimum essential medium (Eagles MEM) (Rickmansworth, England) containing 10% fetal bovine serum (Gibco Company, Grand Island, NY, USA), penicillin (100 U/mL), and streptomycin (100 g/mL). the expressions of cyclin D1, Bax, Bcl-2, and MMP 9 were detected. == Results == As shown by real-time PCR and Western Prodipine hydrochloride blotting, the expression of HMGB1 significantly increased in glioma cells (U251, U-87MG, and LN-18) in comparison with the control cell line (SVG p12); the vitality, proliferation and invasive capabilities of U251 and U-87MG cells in the HMGB1 siRNA-transfected group were significantly lower than those in the blank control group and negative control (NC) siRNA group (P<0.05) but showed no significant difference between the blank control group and NC siRNA group. The percentage of apoptotic U251 and U-87MG cells was significantly higher in the HMGB1 siRNA-transfected group than in the blank control group and NC siRNA group (P<0.05) but was similar between the latter two groups. The HMGB1 siRNA-transfected group had significantly lower expression levels of Cyclin D1, Bcl-2, and MMP-9 protein in U251 and U-87MG cells and significantly higher expression of Bax protein than in the blank control Prodipine hydrochloride group and NC siRNA group (P<0.05); the expression profiles of cyclin D1, Bax, Bcl-2, and MMP 9 showed no significant change in both blank control group and NC siRNA group. == Conclusions == HMGB1gene may promote the proliferation and migration of glioma cells and suppress its effects of apoptosis. Inhibition of the expression ofHMGB1gene can suppress the proliferation and migration of glioma cells and promote their apoptosis. Our observations provided a new target for intervention and treatment of glioma. Keywords:High mobility group protein box 1 (HMGB1), glioma, proliferation, apoptosis, invasion, siRNA == Introduction == A glioma is a primary FABP7 brain tumor Prodipine hydrochloride that originates from the nerve stromal cells including glial cells, ependymal cells, choroid plexus epithelial cells, and nerve parenchymal cells. Gliomas are featured by high morbidity, high recurrence rate, and high case-fatality rate (with an overall 5-year survival of only 13%), and low cure rate. Gliomas account for about 60% of all intracranial primary brain tumors, posing serious threat to the life and health of patients (1,2). Tumor invasion and metastasis are important biological characteristics of malignant tumors. Most patients who die of cancer die from metastatic disease rather than from the primary lesion (3,4). Gliomas are highly invasive. They often invade the surrounding normal brain tissue, and have no clear boundaries with normal brain tissues. Thus, surgery has only a limited role in treatment, and the case-fatality rate of gliomas is extremely high (1,5,6). Cancers are caused by the accumulation of genetic mutations, including the activation of oncogenes and the loss of tumor suppressor genes. Activation of oncogenes can lead to cell malignant transformation and tumorigenesis (7-9). Most studies have shown that the activation of oncogenes play key roles in the occurence and development of gliomas (10-12). Activation of oncogenes usually entails the changes in multiple signaling pathways, cell cycle, and rules of apoptosis (13-16). Recent research has shown the high mobility group protein package 1 (HMGB1) gene is definitely highly expressed Prodipine hydrochloride in various tumours, showing oncogene-like functions (17-19). Forty years ago, HMGB1 was found out in calf thymus and named relating to its electrophoretic mobility in polyacrylamide gels (20). Human being HMGB1 is definitely a structural transcription element encoded by a single gene. Located in chromosome 13q12, it contains four introns and five exons, encoding a 215-amino-acid protein, having a molecular excess weight of about 30 KD. It is highly conserved, with an amino acid sequence homology of over 98% between human being and rodents (21,22). HMGB1 protein is divided into three domains: two positively charged DNA-binding motifs (boxes A, B) and a C-terminal acidic tail. Both the.