Fig. 6.

Enhanced radiosensitivity of NPC by OL can be reversed by HIF1α and PDRG1. a and b Using a lentivirus based stable overexpression system, NPC cells HNE-1 (a) and HONE-1 (b) stably expressing empty vector, and overexpressing either HIF1α or PDRG1, respectively, were incubated for 24 h with media containing 200 μM of OL, with 0 μM OL treatment as control, and then subjected to radiation dosage as indicated. c and e Growth curve of HNE-1 (c) and HONE-1 (d) xenograft tumors expressing empty vector, and overexpressing either HIF1α or PDRG1, respectively, in mice after OL treatment, with no OL administration as control (n = 10 each). e and f At the end of animal studies (day 21), xenograft tumors were harvested to examine the expressions of HIF1α (e) and PDRG1 (f) following respective treatments as shown. Values were expressed as mean ± SD. * p < 0.05, ** p < 0.01, compared to 0 μM/no OL, OL + HIF1α and OL + PDRG1. # p < 0.05, ## p < 0.01, compared to OL + vector