Figure 8: System xC− antagonists synergize with APR-246 in vivo.
From: Inhibiting the system xC−/glutathione axis selectively targets cancers with mutant-p53 accumulation
(a) Example fluorescence imaging of mice bearing FLO-1 xenografts transduced with a doxycycline (dox)-inducible dual fluorescent vector with shSLC7A11 cloned in (top). Western blot of FLO-1 xenografts 72 h post dox (Food: 600 mg kg−1, water: 2 mg ml−1) induction to assess the extent of knockdown using two hairpins (sh) against SLC7A11 (Bottom). (b,c) Growth curves of FLO-1 tumours transduced with shSLC7A11_1 (b) and shSLC7A11_2 (c) hairpins in mice treated with APR-246 (100 mg kg−1, daily) and/or dox for 28 days. n=5 per group. (d) Kaplan–Meier plot of time to reach 1,500 mm3 tumour volume in mice bearing FLO-1 tumours transduced with shSLC7A11_1 and treated according to conditions detailed in b. (e) Intratumoral GSH levels in FLO-1 xenografts transduced with shSLC7A11_2 at 28 days post treatment. (f) Growth curves of FLO-1 xenografts in mice treated with either vehicle (0.9% saline, daily, n=7), APR-246 (100 mg kg−1, daily, n=7), sulfasalazine (SAS, 6 mg, twice daily, n=6) or APR-246 and SAS (n=6) for 28 days (top). Body weight at 28 days post treatment as a percentage change from baseline (bottom). Ethically acceptable weight loss is defined by the Peter MacCallum Cancer Centre Animal Experimentation Ethics Committee as <20% compared to pre-treatment body weight (within the dotted lines). (g) Growth curves of Patient-derived xenograft 4 (PDX4) in mice treated with the same drug regimen as (f) for 14 days. Vehicle: n=9, all other groups: n=8. (h) Representative western blot of PDX4 demonstrating the accumulation of mut-p53 protein. (i) Intratumoral GSH levels in PDX4 at 14 days post treatment with drug regimens detailed in g. (j) Representative H&E, Ki67 and Cleave caspase 3 staining of PDX4 tumours (left) and their respective quantification (right). Scale bars=100 μm. Grey shading: treatment period. One-way ANOVA with Dunnett’s multiple comparison post-test (b–g,i,j). Error bars=s.e.m., *P<0.05, **P<0.01, ***P<0.01. See also Supplementary Fig. 8.
