WNT/β-Catenin Signaling Inhibitor IC-2 Suppresses Sphere Formation and Sensitizes Colorectal Cancer Cells to 5-Fluorouracil

Abstract

Background/aim: Colorectal cancer (CRC) is one of the most malignant types of cancer worldwide. Recent studies suggest that a small subpopulation of cells, so-called cancer stem cells (CSCs), promote the high metastasis and relapse associated with CRC. WNT/β-catenin signaling plays a critical role in CSC maintenance. Therefore, its inhibitor may suppress CSCs and improve therapeutic effects on CRC.

Materials and methods: The effects of a derivative of WNT/β-catenin signaling inhibitor, IC-2, which we recently developed, on the CRC cell line DLD-1, were examined by luciferase reporter assay, WST assay, western blot, and sphere assay.

Results: The reporter assay showed that IC-2 reduced WNT/β-catenin transcriptional activity in DLD-1 cells. Notably, IC-2 reduced expression levels of CSC marker proteins, as well as sphere formation. In addition, IC-2 increasesd cytotoxicity of 5-fluorouracil (5-FU) in DLD-1 cells.

Conclusion: These results suggest that the combination treatment of IC-2 and 5-FU can stimulate tumor-suppressive effects on CRC.

Keywords: 5-fluorouracil; Colorectal cancer; WNT/β-catenin signaling inhibitor; cancer stem cells; small molecule compound.