Figure 2.

Exogenous Shh N-terminal peptide protected human glioblastoma cells against radiation cytotoxicity. (a) U87MG cell radiation survival curves. D0 values (radiation dose with 37% survival) of U87MG cells for control, Shh 0.01 ng/mL, Shh 0.1 ng/mL and Shh 1.0 ng/mL were 4.7 Gy, 6.6 Gy, 6.2 Gy and 7.7 Gy, respectively. (b) U373MG cell radiation survival curves. D0 values (radiation dose with 37% survival) of U373MG cells for control, Shh 0.01 ng/mL, Shh 0.1 ng/mL and Shh 1.0 ng/mL were 3.6 Gy, 4.2 Gy, 4.5 Gy and 6.5 Gy, respectively. Cells were plated for colony formation assay after radiation. After 10–14 days, the dishes were stained with crystal violet, and colonies containing ≥50 cells were counted (in materials and methods section). Data from three separate experiments were expressed as mean ± standard error of mean. Symbol: control (closed circle), Shh 0.01 ng/mL (black down-pointing triangle), Shh 0.1 ng/mL (up down-pointing triangle), Shh 1.0 ng/mL (open circle)