Fig. 4
Ad-OSM and NDV-OSM show limited antitumor effect as monotherapy. Tumors were established by intrapancreatic inoculation of HaP-T1 cells. a Left panel shows the histopathological examination of a representative tumor (Hematoxylin/Eosin staining, magnification x400). Note the infiltration of normal pancreas and engulfment of secretory acini (white arrows). Right panel shows a schematic representation of the experimental setting. Treatments started 2 weeks after cell implantation (referred to as day 0) by intratumoral (i.t.) injection of Ad-OSM or NDV-OSM (n = 6-12). Control animals received the same volume of saline solution (n = 12-16). A second dose of each virus or saline was administered at day 3. All hamsters were sacrificed one month after the initiation of treatment. b Concentration of hOSM and type I IFN in the serum of hamsters 24 h after treatment with the indicated viruses, determined by ELISA and bioassay, respectively. Viral doses correspond to i.u. (x108). c Apart from the efficacy study, an independent group of tumor-bearing hamsters (n = 5) received Ad-OSM at 2.5 × 108 i.u. at days 1 and 3 (arrows), and serum hOSM concentration was quantified right before and 24 h after each virus administration. d Individual tumor volumes and group averages determined by necropsy one month after initiation of treatments in the efficacy study. n.d., not determined due to early death of animals. e Additional groups of hamsters (n = 5) received Ad-OSM (2.5 × 108 i.u/hamster), NDV-OSM (1 × 109 iu/hamster) or saline (control), and were sacrificed 48 h after treatment for histopathological examination of tumors. Microphotographs show Hematoxylin/Eosin staining, magnification X100). The percentage of necrotic area in each group (n = 5) is represented in the right panel. * p < 0.05, ** p < 0.01