MAPK8 and malignant colon neoplasm: The role of JNK-JUN signaling in resistance to MEK inhibitors is further supported by the finding that knockdown of JUN with shRNAs confers sensitivity to MEK inhibition and the notion that two different JNK kinase inhibitors synergize with MEK inhibition in breast and colon cancer cells (Supplementary information, Fig. S3a–c).