The effect of edelfosine on CTP: Cholinephosphate cytidylyltransferase activity in leukemic cell lines

• Published in: Leukemia research Vol. 20; no. 11; pp. 947 - 951
• Main Authors: Vogler, William R., Shoji, Mamoru, Hayzer, David J., Xie, Y.P., Renshaw, Mary
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.11.1996; Elsevier Science
• Subjects: Antineoplastic agents; Antineoplastic Agents - pharmacology; Biological and medical sciences; Choline-Phosphate Cytidylyltransferase; cholinephosphate cytidylyltransferase; CTP; DNA, Complementary - genetics; DNA, Neoplasm - genetics; Drug Resistance, Neoplasm; edelfosine; General aspects; HL-60 Cells - drug effects; HL60; Humans; K562; Leukemia, Myelogenous, Chronic, BCR-ABL Positive - pathology; Medical sciences; Neoplasm Proteins - antagonists & inhibitors; Neoplasm Proteins - metabolism; Nucleotidyltransferases - antagonists & inhibitors; Nucleotidyltransferases - metabolism; PCR; Pharmacology. Drug treatments; Phospholipid Ethers - pharmacology; Polymerase Chain Reaction; Tumor Cells, Cultured - drug effects; edelfosine; K562; CTP; PCR; HL60; Antineoplastic agent; Human; Edelfosine; Enzyme; Transferases; Leukemia; Cytotoxicity; Malignant hemopathy; Choline-phosphate cytidylyltransferase; Metabolism; In vitro; Biological activity; HL60 cell line; Nucleotidyltransferases; Enzymatic activity; Established cell line; Phosphatidylcholine; Mechanism of action; Comparative study
• ISSN: 0145-2126; 1873-5835
• DOI: 10.1016/S0145-2126(96)00070-7

Analogs of ether phospholipids have been shown to have selective anti-neoplastic activity. The compounds are known to inhibit phospholipid biosynthesis. This paper examines the effect of the alkyl-lysophospholipid, edelfosine, on the rate-limiting enzyme, CTP:choline-phosphate cytidylyltransferase, in de novo phosphatidylcholine synthesis in sensitive and resistant leukemic cell lines. Enzyme activity was measured by the incorporation of 14C-phosphocholine into CDP-choline by lysates of HL60 and K562; cells demonstrated inhibition of incorporation of 14C-phosphocholine in HL60 cell lysates but no inhibition in K562 lysates. Partial purification of cytidylyltransferase by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting demonstrated similarity between the enzyme isolated from each cell line. Cloning and sequencing of cytidylyltransferase cDNA of HL60 cells was accomplished using a probe encoding the entire protein sequence of the K562 cytidylyltransferase gene. A substitution at nucleotide 751 from A in the HL60 cell cDNA clone to G in the K562 cDNA clone resulted in a change in amino acid number 251 from lysine (positively charged) in the HL60 enzyme to glutamic acid (negatively charged) in the K562 enzyme. This negative charge in the lipid-binding domain of the K562 enzyme may result in a weaker binding of edelfosine and the observed decrease in activity, as evidenced by resistance to edelfosine by K562 cells.