Substrate-specific deoxycytidine kinase deficiency in 1-β-D-arabinofuranosylcytosine-resistant leukemic cells

• Published in: Cancer research (Chicago, Ill.) Ill.), 1990-10, Vol.50 (20), p.6515-6519
• Main Authors: RICHEL, D. J, COLLY, L. P, ARKESTEIJN, G. J. A, ARENTSEN-HONDERS, M. W, KERSTER, M. G. D, TER RIET, P. M, WILLEMZE, R
• Format: Article
• Language: English
• Subjects: Animals; Antineoplastic agents; Biological and medical sciences; Cell Survival - drug effects; Chromosome Aberrations; Cytarabine - metabolism; Cytarabine - pharmacology; Deoxycytidine Kinase - analysis; Deoxycytidine Kinase - deficiency; Deoxyribonucleotides - analysis; Drug Resistance; General aspects; Isoenzymes - analysis; Leukemia, Myeloid - genetics; Leukemia, Myeloid - pathology; Medical sciences; Pharmacology. Drug treatments; Rats; Rats, Inbred BN; Substrate Specificity; Tumor Cells, Cultured - drug effects
• ISSN: 0008-5472; 1538-7445

In this study we describe the establishment of a leukemic cell line (BNML-CL/ara-C), originating from the 1-beta-D-arabinofuranosylcytosine (ara-C)-resistant brown Norway rat myelocytic leukemia model (BNML/ara-C), that retains the in vivo generated ara-C resistance. Its biological and biochemical characteristics have been compared with a cell line, derived from the ara-C-sensitive BNML model (BNML-CL/O). Resistance to ara-C was attributed to a decrease in phosphorylation of ara-C. Deoxycytidine (dCyd) kinase activity in crude cell extracts with dCyd as substrate showed similar enzyme activities in both cell lines, whereas with ara-C as substrate no dCyd kinase activity was detectable in the ara-C-resistant cell line. Two isoenzymes of dCyd kinase with different substrate specificities have been described (Cheng, Y.C., Domin, B., and Lee, L.S. Biochim. Biophys. Acta, 481: 481-492, 1977), cytoplasmic (dCyd kinase I, substrates: dCyd and ara-C) and mitochondrial (dCyd kinase II, substrates: dCyd and thymidine). In the ara-C-sensitive BNML model, thymidine induced a reduction of dCyd kinase activity when dCyd was used as substrate. However, thymidine did not affect kinase activity with ara-C was used as substrate. In the BNML-CL/ara-C, thymidine even induces a dCyd kinase inhibition of 85% with dCyd as substrate. It is likely that the ara-C-specific dCyd kinase deficiency in BNML-CL/ara-C cells was due to a selective loss of dCyd kinase I, whereas dCyd kinase II activity remained intact.