In vivo analysis of apoptosis in Colon-26 tumors treated with AdNK4 using the TUNEL assay.
To demonstrate the apoptosis induced by AdNK4 in vivo, BALB/c mice were injected subcutaneously in the flank with 2 × 105Conlon-26 cells (day 0). On day 8, tumor-bearing mice were treated by intratumoral injection of 109 pfu of AdNK4 (A), AdNull (B), or PBS alone (no transduction, C). On day 11, tumors were dissected, and in frozen tumor sections, the fragmented DNA of apoptotic cells were labeled by fluorescein-12–uridine triphosphate (UTP) incorporation at 3′-OH DNA ends. Following terminal transfer of fluorescein-12–UTP, sections were counterstained with propidium iodide (PI). Each fluorescent image was viewed for fluorescein (green fluorescence shown in the left panel) and PI (red fluorescence shown in the right panel). AdNK4-transduced tumors had some apoptotic cells, whereas control tumors (ie, AdNull-transduced and nontransduced tumors) had minimal apoptotic cells. Original magnification × 400. The number of apoptotic cells per 10 random high-power fields is indicated in the lower right corner of each left panel.
