Fig. 2

Irbesartan efficiently overcomes GEM resistance of PDAC in PDO, PDX and GEM-resistant BxPC-3 models in vitro and in vivo. A The schematic illustration for human PDAC organoid apoptosis evaluation. B The apoptosis of organoids treated with GEM (0.8 μM) and irbesartan (1 μM) for 72 h was determined by western blot for cleaved-caspase 3/7. Tubulin was used as loading control. C-H Organoids were treated with vehicle, GEM (0.8 μM), irbesartan (1 μM) and GEM (0.8 μM) plus irbesartan (1 μM), followed by continually monitoring PDAC organoid apoptosis by real-time caspase3/7 probe imaging for 72 h. Representative apoptotic images of organoids in 72 h (PDO1#, C; PDO2#, F) and real-time apoptotic imaging analysis (PDO1#, D; PDO2#, G) were shown. For analyzing the synergy score of irbesartan and GEM, organoids were treated with drugs in a constant concentration (irbesartan 0–6.4 μM, GEM 0–1.6 μM) for 72 h using Synergy finder (PDO1#,E; PDO2#,H). I-J Tumor volumes of PDOX were monitored by MRI scan. Representative MRI images per group at day 36 were shown (I) and tumor volumes were calculated by MRI scan (n = 6 per group, J). K Representative pancreatic tumor images per group at the experimental ending were shown (left) and tumor weight was determined (right). L Kaplan–Meier survival curves with log-rank test were used to analyze the effects after drug treatment in another cohort (n = 6). M–N The apoptotic and proliferative level of PDOX tumor in mice were evaluated by TUNEL staining and Ki67 staining. All experiments were repeated three times independently. Paired Student’s t-test were used for in vitro experiments. Un-paired Student’s t-test were used for in vivo experiments