Cyclopentenylcytosine (CPC), a nucleoside analog, effectively inhibits CTP synthetase, leading to reduced levels of cytidine triphosphate (CTP) and deoxycytidine triphosphate (dCTP) in leukemic cells. Furthermore, it enhances the phosphorylation of 1-β-D-arabinorubosylmannosylcytidine (araC) and increases its DNA intercalation activity. In the human T lymphocyte line MOLT-3, cyclopentenylcytosine triggers apoptosis and necrosis in a dose (50-300 nM) and time (8-16 h) dependent manner. When used in conjunction with araC, cyclopentenylcytosine augments the induction of both apoptosis and necrosis, amplifying its cytotoxic effects on T lymphoblasts .