Fig. 1

Cell morphology of Regorafenib-resistant LS-180 cell line at the end of each cyclic is shown. The cells were resistant during four cycles using a fixed dose of 40 µM Regorafenib. As we approached the last cycles, the cells became less sensitive to the drug. To the extent that the behavior of cells over the fourth cycle was no different from that of cells that grew in drug-free media. T: treatment; R: recovery