In vitro KSY treatment decreases cancer cell viability, suppresses proliferation, and interferes with cell cycle progression . (a) The viability of MBT-2 cancer cells (3,000 cells/well in a 96-well plate) was determined by an MTT assay after a 24, 48, or 72 h vehicle or drug treatment at indicated concentrations. Doxorubicin (Lipo-Dox) served as the positive control. (b) An MTT assay was also used to measure the viability of primary MEF cells (3,000 cells/well in a 96-well plate). (c) MBT-2 cancer cells (1 × 105) were treated with different concentrations of KSY for 24, 48 or 72 h, and the viable cells were determined using Trypan blue exclusion assays. Doxorubicin (Lipo-Dox) served as the positive control. (d) MBT-2 cells (1 × 105) were treated with different concentrations of KSY for 24 h and then analyzed with BrdU/PI staining and flow cytometry. Representative FACS dot plots are shown in the left panel, and DNA synthesis (S phase) was determined by quantifying the BrdU-positive cells in the dot plot. Quantification data of BrdU-positive cells are shown in the right panel. *indicates p < 0.05 versus the vehicle group.