High-mobility group box 1 is overexpressed in cervical carcinoma and promotes cell invasion and migration in vitro

The present study aimed to investigate the expression of high-mobility group box 1 protein (HMGB1) in cervical carcinoma and explore whether or not HMGB1 promotes cervical carcinoma cell invasion and migration in vitro and the related mechanism. HMGB1, nuclear factor-kappa B (NF-kappa B), E-cadherin and N-cadherin protein expression was analyzed in tissues from 48 cervical carcinomas, 51 cervical intraepithelial neoplasia (CIN) and tissues from 24 healthy controls using immunohistochemistry. HeLa cells were treated with different concentrations of HMGB1 (0, 10, 100, and 1,000 ng/ml) at different time-points (0, 24, 48 and 72 h), and changes in cell morphology and biological behaviors were observed. Changes in the expression levels of E-cadherin, N-cadherin, NF-kappa B and the inhibitor kappa B (I kappa B) in the treated cells were detected by western blot analysis and real-time PCR. HMGB1 expression exhibited a gradually increasing trend in the normal cervical tissues, CIN and cervical cancer, and there was statistical significance between the three groups (P<0.05). HMGB1 expression level was associated with FIGO stage, lymph node metastasis and differentiation (P<0.05). HMGB1 expression was positively related to N-cadherin and NF-KB; and HMGB1 had a negative relationship with E-cadherin. HMGB1 stimulation caused HeLa cells to lose cell polarity and transition from epithelial cells into spindle-shaped cells with sparse cell-cell junctions. The expression levels of E-cadherin and I kappa B in the cytoplasm were reduced, while N-cadherin expression was increased. The level of NF-kappa B expression in the nucleus was also increased. Treatment with NF-kappa B inhibitor (BAY11-7082) and receptor for advanced glycation end products (RAGE) antagonist (anti-RAGE) significantly suppressed HMGB1-mediated epithelial-to-mesenchymal transition in the HeLa cervical cancer cells. The results suggest that HMGB1 is associated with outcomes of cervical cancer and promotes subsequent invasion and metastasis of cervical cancer cells by activating the NF-kappa B signaling pathway. This potential mechanism could be an important determinant of cervical cancer metastasis.