A-D), Viability of mouse (A,C) and human (B,D) ATC cell lines exposed to the SHMT1/2 inhibitor SHIN1 (A,B) and to the MTHFD2 inhibitor DS18561882 (C,D). In B and D, cell lines are color coded based on their driver genetic alterations: mutant BRAF (red), mutant RAS (blue), mutant PI3K (green), mutant BRAF and PI3K (maroon), mutant BRAF and RB1 (brown). E) Differential effect of regular and dialyzed FBS on the proliferation of ATC cells upon SHMT1/2 inhibition. F) Representative analysis of cell cycle distribution of BHT101 cells treated with SHIN1 for 72h. Equivalent results were obtained with other ATC cell lines (not shown). G) Representative colony forming assays of six human ATC cell lines treated for two weeks with 10μM SHIN1. In the last row, SHIN1 was removed after one week.