MTT assay

Cell viability was detected by the MTT assay (Sigma-Aldrich; Merck KGaA). HCT116 and SW620 cells were digested, dispersed and inoculated in 96-well plates at a density of 1×10⁴ cells/well and 2×10⁴ cells/well, respectively. The cells were cultured in complete DMEM and incubated in a 37°C incubator containing 5% CO₂. After cells were allowed to proliferate for 24 h, RPMTG at different concentrations (0, 100, 200, 250, 300, 400 and 500 µg/ml) was added; after 12 and 24 h, 15 µl MTT was added into each well of the blank group and the RPMTG treatment group; after a further 4 h, DMSO was added, and the plates were analysed at 490 nm on a microplate reader (Thermo Fisher Scientific, Inc.). The ratio of cell survival was calculated against that of the untreated CRC cell group.