Fig. 3
Identification and activity of a new SLC25A1 inhibitor. a Comparison of the structure and properties of citrate, BTA, CTPI-1 and CTPI-2 and general structure SLC25A1 inhibitors (top panel): a: Calculated octanol–water partition coefficient; b: Topical polar surface area (TPSA); c: Experimental dissociation constant. d: Docking score calculated by the UCSF DOCK6.7 software. b The structure of the leading compound (CTPI-1) and of the newly identified SLC25A1 inhibitor (CTPI-2) are shown. c A binding model for citrate, CTPI-1 or CTPI-2 in complex with a homology model of human SLC25A1. The Dock6.7 software provided a score for binding and a potential pose for the structure. Refinement of the structure using the AMBER MD module in the UCSF Dock6.7 suite of software was performed to give the optimized models. The model shows the relevant amino acids previously known to be involved in citrate binding, including Lys147, Lys245, Arg285, Lys50 and Arg282. d Proliferation rates assessed with crystal violet of H1299 transduced with control or with the SLC25A1-shRNA lentivirus or fold proliferation changes of cells transfected with the SLC25A1R282G/R285C and treated with CTPI-2, respectively. e Gene expression arrays performed on Illumina Human HT-12 v4 Bead Chip of cells expressing the SLC25A1-shRNA or treated with CTPI-2. A cutoff of fold change >2-fold over control, was used to evaluate the similarity of gene expression profile changes between the shRNA and CTPI-2 treatment. The overlap p-value (hypergeometric test) of <10−716 is shown. f Comparison of the activity of CTPI-1 and CTPI-2 in sphere-forming assays at the indicated concentrations. Asterisks indicate p-values calculated from cells plated in five or six independent wells and comparisons refer to untreated control cells
