The Level of TWIST1 expression determines the response of colon cancer cells to mitogen-activated protein kinases inhibitors

BACKGROUND/AIM: Currently, it has been proposed that combination of 5-fluorouracil (5FU) with inhibitors of the mitogen-activated protein kinases (MAPKs) signaling pathway might enhance the efficacy of 5FU-based chemotherapy in colon cancer. Our study aimed to investigate an impact of TWIST1 silencing on the sensitivity of cancer cells to 5FU and selected MAPK inhibitors. MATERIALS AND METHODS: The suppression of TWIST1 expression in human colon cancer HT29 and HCT116 cell lines was achieved by transduction with lentiviral vector carrying the TWIST1 silencing sequence (pLL3.7-sh TWIST1). The statistical calculation was performed with analysis of variance or Dunnett's test for comparison to control group. Paired Student's t-test was performed when two groups were analyzed. RESULTS: Suppression of TWIST1 reduced the proliferation rate of colon cancer cells and enhanced their sensitivity to 5FU and MAPKs inhibitors. The sensitivity of HT29 cells to examined compounds was more dependent on TWIST1 expression level compared to HCT116 cells. The most noticeable effect of TWIST1 suppression on sensitivity of both colon cancer cell lines to combined treatment of 5FU and the MAPKs inhibitors was observed for inhibitors of p38α/β and JNK1-3. We also noted that the suppression of TWIST1 significantly sensitized both cell lines to combined treatment of 5FU and Rac inhibitor. CONCLUSIONS: Our observations point to TWIST1 expression level as a marker of colon cancer sensitivity to combined treatment of 5FU and MAPKs inhibitors.