Fig. 6
From: Sulindac (K-80003) with nab-paclitaxel and gemcitabine overcomes drug-resistant pancreatic cancer
cFAM124A activates PI3K/Akt pathway through tRXRα to cause GEM resistance in PDAC, and K-80003 can reverse this effect. A, Western blot analysis of Akt, p-Akt (Ser473), p-Akt (Thr308), and cleaved caspase 3/8 expression after 6 h of treatment with different inhibitors and GEM treatment. B, IC50 values for GEM in PDAC cells overexpressing cFAM124A and control cells after 6 h of treatment with different inhibitors and GEM treatment. C, Necrosis in 3D tumor microspheres based on PI staining (red) and after 6 h of treatment with different inhibitors and GEM treatment. Scale bar, 100 μm. D, Colony formation by cells overexpressing cFAM124A after 6 h of treatment with different inhibitors and GEM treatment in 6-well dishes (800 cells/well) for 2 weeks. Each inhibitor, copanlisib (2 nM, pan-PI3K inhibitor) or K-80003 (5 nM, tRXRα-dependent Akt activation inhibitor). Quantitative data are shown on the right. E, Subcutaneous xenograft model of mice in the different groups treated with GEM (40 mg/kg i.p. 2×/week for 4 weeks), copanlisib (1 mg/kg, iv. 2×/week for 4 weeks), or K-80003 (20 mg/ kg i.p. 2×/week for 4 weeks) at 2 weeks after subcutaneous injection of 5 × 106 cells overexpressing cFAM124A and control cells. Representative images of tumors are shown (n = 5). F, Body weights of subcutaneous tumor-bearing mice in the indicated groups (n = 5). G, Volcano plot showing upregulated and downregulated protein between EV-PATU8988T and cFAM124A-PATU8988T cells. H, Western blot analysis of RXRα, Akt, p-Akt (Ser473), and p-Akt (Thr308) expression in PDAC cells overexpressing cFAM124A or with cFAM124A knockout and control cells. I, cFAM124A increased RXRα protein degradation: Indicated PDAC cell lines were incubated with CHX for indicated time periods before western blot analysis of RXRα and GAPDH expression. Representative images are shown (left). J, Indicated PDAC cell lines were incubated with MG132 and then with CHX for indicated time periods before western blot analysis of RXRα and GAPDH expression. Representative images are shown (left)