Pro-invasive effect of irradiation on human glioblastoma cell line U87 and its possible mechanism / 中华放射肿瘤学杂志

ABSTRACT

Objective To study the pro-invasive effect of irradiation on human glioblastoma cell line U87 and its possible mechanism.Methods Cultured U87 cells received different doses of irradiation (0,2,and 4 Gy).The change in cellular invasiveness was measured using the real-time cell analyzer system.The activities of matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-9 (MMP9) in U87 ceils were measured by gelatin zymography before and after irradiation.The content and distribution of intracellular β-catenin after irradiation were determined by immunohistochemistry.The mRNA levels of Wnt/β-catenin target genes were measured by real-time quantitative PCR.Results After irradiation,the invasiveness of U87 cells increased significantly (P ＜ 0.01),which was dose-dependent within a certain dose range; the activities of MMP2 and MMP9 in U87 cells increased significantly (P =0.031 for MMP2 ; P =0.004 for MMP9) ;the content of β-catenin in U87 cells increased significantly (P ＜ 0.01),with translocation from the cell membrane and adherens junctions to the nucleus; the mRNA levels of Wnt/β-catenin-related genes (FZD7 and TCF1) increased significantly (P ＜ 0.01),and the transcription of Wnt/β-catenin target genes,especially those related to migration and invasion such as MMP2,MMP7,MMP9,and CD44,was significantly enhanced (P ＜ 0.05).Conclusions Irradiation can promote the invasion of glioblastoma U87 cells,possibly by activating the Wnt/β-catenin pathway and enhancing the transcription of migration-and invasion-related genes.