FIGURE 2 from Combined Targeting of NAD Biosynthesis and the NAD-dependent Transcription Factor C-terminal Binding Protein as a Promising Novel Therapy for Pancreatic Cancer

Genetic depletion or pharmacologic inhibition of CtBP sensitizes PDAC cells to GMX1778 growth inhibition. A, GMX1778 EC50 values for PaTu8988T or SUIT2 cells expressing shGFP, shCtBP1, or shCtBP2 as measured by 72 hours MTT assay. B, qPCR analysis of TIAM1 (CtBP target gene) mRNA expression after treatment of PaTu8988T cells expressing shGFP or shCtBP1 with Vehicle (0) or indicated concentrations of GMX1778 for 24 hours. The calculation was performed using the ΔΔCt approach. P values were determined by Student t test for comparison with vehicle-treated shGFP cells. C, Representative colony formation assay of PaTu8988T cells treated with Vehicle (top row) or 2 nmol/L GMX1778 (bottom row) for 24 hours, followed by treatment with Vehicle (plate 5) or indicated concentrations of 4-Cl-HIPP (plates 6–8) for 7 days, followed by crystal violet staining. D, Colony formation assay in C was quantified by measuring A592 of solubilized crystal violet. P values were determined by Student t test for comparison with vehicle-only treated cells. E, Calculation of GI50 values for 4-Cl-HIPP treatment of PaTu8988T cells with or without 2 nmol/L GMX1778 derived from colony formation assay in C. #indicates the EC50 or GI50 could not be calculated and beyond the upper range of the titration of GMX1778 or 4-Cl-HIPP, respectively. Error bars indicate ± 1 SD. N = 3 independent experiments. *, P < 0.05; **, P < 0.01; ***, P < 0.005.