Figure 5
Histology of glioblastoma IGRG121 treated with RT and ONYX-015. Immunohistochemical staining of adenoviral hexon protein (A, E, I, M, Q), terminal deoxynucleotidyl transferase-mediated fluorescein-dUTP nick end labelling (TUNEL) (B, F, J, N, R), haematoxilin–eosin–safranin staining (C, G, K, O, S), and Masson's trichrome staining in IGRG121 human glioblastoma xenografts treated with PBS (A, B, C, D), 5 Gy TBI (E, F, G, H), ONYX-015 107 PFU day−1 × 5 (I, J, K, L), 5 Gy TBI and ONYX-015 107 PFU day−1 × 5 (M, N, O, P) or ONYX-015 108 PFU day−1 × 5 (Q, R, S, T). Tumours were excised from nude mice on day 5 (IHC and TUNEL staining) or day 10 (HES and Masson's trichrome staining) after treatment start. In IHC, nuclei containing the adenoviral hexon protein are stained brown. Adenoviral replication was not increased after RT (M) compared with ONYX-015 107 PFU day−1 × 5 alone (I). Five 108 PFU ONYX-015 injections induced significant features of apoptotic cell death displaying compaction or segregation of the nuclear chromatin, or breaking up of the nucleus into discrete fragments ((R), TUNEL-positive cells are stained in red) compared to untreated controls (B). Apoptotic rate was insignificantly increased 5 days after irradiation treatment of 5 Gy (F), ONYX-015 107 PFU day−1 × 5 (J), and in tumours treated combined with irradiation and ONYX-015 107 PFU day−1 × 5 (N). ONYX-015 108 PFU day−1 × 5 induced preapoptotic changes and tumour cell necrosis (S). After 5 Gy TBI and ONYX-015 107 PFU day−1 × 5 cells, foci of viable tumour cells were surrounded by inflammatory cells and prominent fibrosis (O); collagen type I as marker for fibrosis is stained in blue (P). Hexon IHC and TUNEL were photographed at × 100 original magnification, HES and Masson's trichrome staining at 50 × original magnification.
