Objective: To investigate the effect of high mobility group box-1 (high mobility group box B 1, HMGB1) on the invasive and metastatic abilities of gastric cancer cell line MGC-803 and analyze the possible mechanisms.
Methods: HMGB1 gene targeting siRNA was designed and synthesized, and HMGB1 siRNA oligonucleotides were transfected into the MGC-803 cells with Lipofectamine 2000. The invasive and migratory abilities were detected by transwell assay and scratch assay. The Matrigel matrix glue adhesive ability of MGC-803 cells was evaluated by MTT assay. NF-κB activity was detected by electrophoretic mobility shift assay. The mRNA and protein levels of HMGB1 and MMP-9 were determined by RT-PCR and Western blot, respectively.
Results: The siRNA down-regulated the levels of HMGB1 mRNA and protein. Compared with that of the control group, the number of invasive (142.7 ± 3.4 /view vs. 303.5 ± 4.3/view) and migratory (293.7 ± 4.4/view vs. 445.5 ± 5.6/view) cells was significantly increased (P < 0.05) and the adhesive ability of MGC-803 cells to Matrigel was significantly elevated (33.4 ± 0.03% vs. 57.4 ± 4.2%, P < 0.05). In addition, silencing of HMGB1 gene significantly inhibited the activity of NF-κB and the relative expression folds of mRNA (0.2 ± 0.1 vs. 1.4 ± 0.4, P < 0.05)and protein (0.4 ± 0.1 vs. 2.3 ± 0.7, P < 0.05) of MMP-9.
Conclusion: Silencing of HMGB1 can effectively inhibit the invasion and migration of gastric cancer cells and this effect of HMGB1 may be partly due to its regulation of NF-κB and MMP-9 expressions.