Co-stimulation molecule B7-H6 expression in human glioma tissues and its contribution to the regulation of biological function in human glioma cell line

Abstract

Objective To study the expression of B7-H6, a co-stimulation molecule, in human glioma tumor tissues and its impact on the biological behaviors of human glioma cell line U87. Methods B7-H6 expression in the human glioma tissues was characterized by immunohistochemistry. Down-regulation of B7-H6 was performed by using RNAi method in human glioma cell line U87. Results B7-H6 expression in human glioma tissues was significantly associated with pathologic type (Z/χ2=23.935, P=0.000), grade (Z/χ2=3.008, P=0.003), and tissue type (Z/χ2=13.908, P=0.001). By using the RNA interference technology, we successfully decreased B7-H6 expression in human glioma cell lines. CCK-8 cell proliferation experiment showed that at 72 h, the proliferation rate of U87-B7-H6-siRNA cells was significantly lower than that of U87-NC (P=0.000). The wound healing assay revealed the cell-free area of the U87-B7-H6 group was significantly wider than that of U87-NC group after 24 h (P=0.014). The Transwell invasion assay showed the glioma cells from U87-B7-H6-siRNA group had significantly reduced number of cells invading through the matrigel, as compared to those from U87-NC group (P=0.003). Cell cycle analysis results showed cells from the U87-B7-H6-siRNA group displayed increased percentage of cells in the G1-phase and decreased percentage in G2/M phases, in comparison to those from U87-NC group. Conclusion Expression of B7-H6 is associated with cancer progression and plays an important role in the regulation of the biological behaviors of glioma cell lines. Key words: B7-H6; Glioma; U87; RNA interference