Upregulation of stemness genes in HCC cells after radiation treatment.

<p><b>A and B, E and F</b> HepG2 and Huh7 cells were exposed to 0, 2 or 4 Gy of gamma radiation and total RNA was extracted after 3, 6 or 24 hours. Oct3/4 (a and b) and Sox2 (e and f) mRNA levels in each cell line were then determined by quantitative Real-Time PCR and normalized to GAPDH mRNA levels in each sample. In HepG2 cells, treatment with 2 and 4 Gy of gamma radiation induced a significant increase of Oct3/4 mRNA levels. Sox2 mRNA levels were also strongly upregulated in Huh7 cells following low dose gamma radiation treatment. Results are presented as mean±SEM of four independent experiments. *p<0.05, **p<0.01, ***p<0001 versus t0 sample or untreated samples. The dashed line represents a comparison to the control at the same time point. <b>C and D, </b><b>G and H</b> HepG2 cells and Huh7 cells<b>,</b> were exposed to 0, 2 or 4 Gy of gamma radiation and Oct4 or Sox2 protein expression was determined by Western blot analysis after 6 hours (for Oct4; c and d), or after 4 hours (for Sox2; g and h). Oct4 and Sox2 protein levels increased following radiation treatment consistent with the increases in mRNA levels for each gene.