Figure 1. Silencing of the expression of either NTN4 or ITGB4 induces glioblastoma cell senescence.

The expression levels of NTN4 and ITGB4 were determined in four glioblastoma cell lines by using Q-RT-PCR (A). U251MG cells were infected by lentivirus harboring shRNAs of target genes and nontargeting control shRNA (NT-shRNA). The silencing efficiencies of each shRNA were confirmed by Q-RT-PCR (B). Seven days after infection, U251MG cells were fixed and analyzed by the senescence assay. Silencing of either NTN4 or ITGB4 increased the number of cells undergoing senescence (blue color) in beta-gal staining (C). Similar results were observed in T98G, U118, and U87MG cells (D). Mean ± SE, n ≥ 3, * p-value < 0.05.