Aims of study: Natural killer (NK) cells and cytolytic T lymphocytes (CTL) have been implicated as important effectors of antitumor defense. High mobility group nucleosomal-binding domain 2 (HMGN2) may be one of the effector molecules of CTL and NK cells. The antitumor effect and mechanism of HMGN2 was investigated in this study.
Materials and methods: HMGN2 was isolated and purified from the human monocyte cell line THP-1 and then characterized by Tricine-SDS-PAGE, western blot, and mass spectrum determination. Confluent T24 cells were incubated with Klebsiella pneumoniae for 2 h, after which the extracellular bacteria were killed by the addition of gentamicin. The cells then were treated with a variety of concentrations of HMGN2. The effect of HMGN2 on the proliferation of T24 cells was analyzed with MTT, Hoechst and flow cytometry assays.
Results: Cell growth assay results demonstrated that HMGN2 significantly inhibited the growth of T24 bladder cancer cell lines infected by K. pneumoniae. Furthermore, results of the Hoechst and flow cytometry assays indicated that HMGN2 may promote apoptosis in this experimental model. These results suggest HMGN2 could inhibit the growth of the infected human bladder cancer cells in vitro.
Conclusion: HMGN2 protein could inhibit the growth of infected T24 cells in vitro, and the anti-tumor action of HMGN2 was due to induce apoptosis.