Figure 6.

Antitumor Activity of miR124-Sensitive EV-A71 against Gliomas

(A) Replication kinetics of EV-A71 BrCr and EV-A71-miR124T in U87 cells (MOI = 1). (B) U87 cells were infected with virus (MOI = 2) for 48 h. Cytotoxicity was then assessed by an LDH assay. (C–E) Nude mice bearing subcutaneous U87 tumors were treated with intratumoral injection of vehicle (C), EV-A71 BrCr (D), or EV-A71-miR124T (E). Tumor burden was monitored by calculating tumor volume versus time using calipers. (F) Nude mice with intracranial glioma xenografts were treated with vehicle, EV-A71 BrCr, or EV-A71-miR124T. The number of surviving animals was recorded daily and plotted against time. Significance was analyzed by a Kaplan–Meier survival log rank test. (G) Representative results of parallel staining patterns for miR124, viral protein, and virus-induced apoptotic cells in mouse brain after EV-A71-miR124T treatment. Serial sections in the left column were hybridized with the miR124-specific LNA miRCURY probe. Sections in the middle and right columns are consecutive tissue sections of those on the left, and EV-A71-positive cells and apoptotic cells were detected by IHC and TUNEL assay, respectively. Low (a–c) and high (d–f) power views of brain sections. Arrows demarcate approximate edges of the tumor mass where it interfaces with normal tissue. FISH analyses indicate that miR124 (green) is largely restricted in nontumor-bearing areas of the brain. Viral protein-positive and TUNEL-positive cells are marked with black triangles within the tumor. Scale bars, 1 mm (a–c); 200 μm (d); 50 μm (e and f). NS, not significant.