The objective of this thesis was to investigate the cytotoxic effects of BEM-328, a newly synthesized uridine analogue, on HaCaT (human skin keratinocyte cell) and SCC VII (mouse carcinoma cells). BEM-328 is a 5’-deoxynucleoside derivative containing uracil as the nucleobase and a dithioacetate group at the 5’ position. The effects of the compound were compared to how the cell cultures have responded to being treated with DMSO (dimethyl sulfoxide) as well as to control cultures using MTT assays and time-lapse image microscopy. MTT assays were used to determine IC50 concentrations and time-lapse image microscopy was used to study changes in maternal cell size, duration of the cell cycle, and division time. Overall, results indicate that BEM-328 had no significant effect on either cell line but was able to induce cytotoxicity in the SCC VII cell line while leaving the HaCaT cell line virtually unharmed.