Incorporation of N4-behenoyl-1-beta-D-arabinofuranosylcytosine into DNA as 1-beta-D-arabinofuranosylcytosine.

BHAC is a newly synthesized lipophilic derivative of ara-C. To clarify its pharmacological mode of action, P388 murine leukemic cells were incubated with two different types of 14C-labeled BHAC, [cytosine-2-14C]BHAC and [acyl-1-14C]BHAC, and DNA was extracted with phenol. The phenol-extracted DNA was then hydrolyzed by nuclease P1 and analyzed with high-performance liquid chromatography (HPLC). The radioactivity of DNA, from the cells incubated with [cytosine-2-14C]BHAC, was detected as ara-CMP. But the radioactivity of DNA, from the cells incubated with [acyl-1-14C]BHAC, was hardly detected. On the other hand, the main radioactivity of the acid soluble fraction was determined as ara-CTP. On the basis of our results, BHAC is not phosphorylated directly to produce N4-behenoyl-ara-CTP, but is mainly converted to ara-C which subsequently produces ara-CTP, the active metabolite of the drug, and which is then incorporated into DNA.