VEGF-C protein expression levels and regulation in CAL33 cells following P or X irradiation. (a) VEGF-C protein levels at 48 h post-single irradiation (AR-SI): * and *, significantly (P<0.05) increased levels after a low (2 Gy) or high (8 Gy) dose of P and X irradiation, respectively, as compared to CT; #, significantly decreased levels after a high dose of P, as compared to X irradiation; §, significantly increased levels after a high, as compared to a low X irradiation dose; (b) VEGF-C protein levels after cell expansion following the third irradiation (CR-MI): * and *, significantly increased levels after low and high doses of P and X irradiation, respectively, as compared to CT; Concentration in ng/ml, normalized to 1 × 106 cells, and represented as percentage of CT. #, significantly decreased levels after high doses of P, as compared to X irradiation; §, significantly increased levels after high, as compared to low doses of X irradiation; (c) Activity of a short vegf-c promoter (CR-MI); (d) Activity of an artificial promoter having three binding sites for NF-kB (CR-MI); (e) Activity of a VEGF-C 3′UTR reporter gene (CR-MI). * and *, significantly (P<0.05) increased promoter activity after P and X irradiation, respectively, as compared to CT; # and #, significantly decreased activity of MUT, as compared to WT vegf-c promoter after P and X irradiation, respectively; §, significantly decreased promoter activity after P, as compared to X irradiation. CT, control (non-irradiated cells); MUT, mutated, WT, wild type.