The effect of cyclopentenyl cytosine on human SK-N-BE(2)-C neuroblastoma cells.

Human neuroblastoma SK-N-BE(2)-C cell-line cells were cultured in the presence of various concentrations of cyclopentenyl cytosine (CPEC). In the absence of cytidine, the IC50 value of CPEC for SK-N-BE(2)-C cells was 100 nM after 72 hr drug exposure. The IC20 value was 1 microM after 24 hr of exposure to CPEC in the presence of 10 microM cytidine, whereas in the absence of cytidine, CPEC at 1 microM resulted in an IC40 value after 24 hr. Therefore, cytidine partially prevented the cytostatic effect of CPEC. Cells cultured with 1 microM CPEC for 72 hr were enriched by approximately 410% with mono- and oligonucleosomes in comparison with cells cultured without CPEC. This enrichment was partially prevented with 10 microM deoxycytidine and completely prevented with 10 microM cytidine.