Figure 3: In vivo ARID1A/ATR synthetic lethality.
From: ATR inhibitors as a synthetic lethal therapy for tumours deficient in ARID1A
(a). Schematic representation of VX-970 therapy experiment in mice bearing established HCT116 ARID1A+/+ and ARID1A−/− xenografts. Mice were then randomized to treatment cohorts of either VX-970 (60 mg kg−1, 4 × weekly by oral gavage) or vehicle treatments. N=11 mice in each cohort. Mice were treated for a subsequent 40 days. Tumour volume was monitored thrice weekly. (b) Relative tumour volume plot from experiment (A) showing efficacy of VX-970 and selectivity for ARID1A−/− xenografts * P=0.024, ANOVA, and a greater efficacy of VX-970 on ARID1A−/− xenografts compared with ARID1A+/+ xenografts *P=0.006, ANOVA. (c) Schematic representation of tumour incidence experiment in mice with non-established HCT116 ARID1A+/+ and ARID1A−/− xenografts. N=15 mice per cohort. Tumour volume was monitored thrice weekly and overall tumour incidence was assessed 40 days later. (d) Bar chart of tumour incidence 40 days after implantation of HCT116 ARID1A+/+ or ARID1A−/− cells. Numbers above bars indicate the proportion of animals in which a detectable xenograft formed. * P=0.027 Fisher’s exact test. (e,f) Tumour growth from all mice in experiment described in c. * P=0.015 ANOVA. (g). VX-970 dose–response curves from TOV21G (ARID1A mutant) and RMG1 (ARID1A wild-type) tumour cells. Cells were exposed to VX-970 for 5 days. ANOVA P value of <0.0001. (h) Western blot illustrating PARP-1 cleavage in TOV21G cells exposed to increasing concentrations of VX-970 for 24 h before cell lysis. As a positive control cells were exposed to camptothecin (Cpt; 1 μM, 24 h) before cell lysis. PARP-1, cleaved (Clvd) PARP-1 (85 kDa fragment) and tubulin were detected by western blot. (i) Bar chart illustrating apoptotic fraction in RMG1 and TOV21G cells exposed to increasing concentrations of VX-970 for 24 h. *Student’s t-test, P<0.05. (j) Schematic representation of VX-970 therapy experiment in mice bearing established TOV21G. Experiment performed as per (a) but with only 28 days treatment. (k) Relative tumour volume plot from (j) showing efficacy of VX-970 in TOV21G xenografts *P=0.014, ANOVA. (l). Images of vehicle and VX-970-treated TOV21G xenografts after 28 days treatment.
