Fig. 5

Thioridazine exhibits toxicity to CRC cells. A MSS/MSI classification and genetic backgrounds of HT29, LoVo, HCT116, and RKO cells representing the most frequently mutated genes in CRC based on the data obtained from DepMap database. B Clonogenic assay comparing the effect of THD at the dose range from 0.625 to 10 µM on different CRC cells, including HT29, LoVo, RKO, and HCT116. Cells were seeded at the density of 400 cells/well and incubated for 13–19 days. C The apoptosis marker, cleaved PARP was detected using western blotting in the four CRC cells following 72 h of THD treatment (10 µM). D Caspase 3, 9, and 8 activity assay kits were used to check the corresponding apoptosis markers, following 48 h of THD treatment at the concentration of 10 and 15 µM in HT29, LoVo, HCT116, and RKO cells. E The effect of sequential treatment of THD (1 µM) in combination with chemo drugs OXA (0.5 µM) or 5-FU (0.5 µM) was inspected in HT29 via clonogenic assay after 10 days of drug treatment. THD was treated from day 1 to day 3 after cell seeding, before the culture medium was replaced with medium containing chemo drug from day 4 to day 10. Data are mean ± SD (N = 3). *: p < 0.05; **: p < 0.01; ***: p < 0.001