PITX2 and colorectal carcinoma: In our study, we incubated immortalized colon epithelial cells (CCD841CoN) and colon fibroblasts (CCD18Co) with high concentrations of RGS (200 nM and 1,000 nM) for 96 h, similar to the previous treatment of the resistant CRC cell lines (SW48 and Caco-2).