Tezacitabine blocks tumor cells in G1 and S phases of the cell cycle and induces apoptotic cell death

Tezacitabine (FMdC) is a new cytostatic/cytotoxic agent widely investigated in clinical trials and on the cellular level. In a previous paper (3) we worked on human and murine leukemia (L-1210, HL-60, and MOLT-4) cells, and in this paper we investigated the influence of FMdC on the cell cycle and apoptosis in vitro of three other leukemias (CCRF-SB, KG-1, and Jurkat), and human solid tumor (carcinoma) cell lines (COLO-205, MCF-7, and PC-3). We found that FMdC induces the G1 (at concentrations higher than 10 nM). and S-phase (at low concentration) leaky block of the cell cycle. FMdC also effectively induces apoptotic death of cells by the caspase 3/7 pathway. We found also that FMdC induces intensive changes in the protein metabolism. These changes are correlated with the cell death.