Intermittent treatment inhibits cell expansion compared with continuous treatment. (A) Cells were cumate induced for 72 h, reseeded in 96 wells, and cultured for 28 d under continuous or intermittent treatment conditions with 500 nM LGX818. The intermittently treated cells followed a schedule with 7 d on LGX818 and 7 d off, changing media on days 3, 5, and 7 of each week. At the end of each week, cell numbers were quantified using CellTiter-Glo assays and normalized to the initial number of cells seeded. Cell numbers (mean ± SEM) measured at each time point for (B) WM239A-BRAFV600E cells (n = 5 or 6) and (C) WM239A empty vector cells (n = 6) are shown for continuous and intermittent treatments. (D) Western blots of lysates separated by low-bis sodium dodecyl-sulfate polyacrylamide gel electrophoresis show ERK phosphorylation in cells expressing empty vector (lane 1), BRAFV600E (lane 2), and BRAFV600E cells treated continuously “C” or intermittently “I” across the 4 wk with 500 nM LGX818.