Figure 4. Effects of c-Myc expression on LDR induced senescence and unirradiated cell migration. (A) The level of SA-β-gal staining was increased by over-expression of c-Myc in H1299 cells. Radiation induced SA-β-gal was reduced by knockdown of c-Myc using shRNA. Scale bar: 100 μm. (B) Quantification of cell number stained by X-gal after different treatments. (C) Comparison of cell migration rate between normal medium and CM collected from c-Myc cover-expressing cells. (D) Comparison of cell migration rate between normal medium and CM collected from c-Myc knockdown cells. (E) Enhanced migration of H1299 cells by CM collected from LDR irradiated cells was suppressed by knockdown of c-Myc in irradiated cells. *p < 0.05.