Induction of DNA ligase I by 1-beta-D-arabinosylcytosine and aphidicolin in MiaPaCa human pancreatic cancer cells.

Abstract

Exposure of MiaPaCa cells to 1-beta-D-arabinosylcytosine (ara-C) resulted in an increase in DNA ligase levels up to threefold compared to that in the untreated control cells, despite significant growth inhibition. Increased levels of DNA ligase I protein appear to correlate with the appearance of increased mRNA levels. The [(3)H]thymidine incorporation experiment and the biochemical assay of total polymerase activity revealed that an increase in DNA ligase I levels after treatment with ara-C was not accompanied by an increase of DNA synthesis or an increased presence of DNA polymerase activity inside cells. When cells resumed DNA synthesis after drug treatment, DNA ligase I levels began to drop, indicating that increased DNA ligase I is not required for DNA synthesis. An increase in DNA ligase I was also observed in cells treated with aphidicolin, another inhibitor of DNA synthesis that inhibits DNA polymerases without incorporating itself into DNA, indicating that an increase in DNA ligase I levels could be caused by the arrest of DNA replication by these agents. Interestingly, caffeine, which is a well-known inhibitor of DNA damage checkpoint kinases, abrogated the increase in DNA ligase I in MiaPaCa cells treated with ara-C and aphidicolin, suggesting that caffeine-sensitive kinases might be important mediators in the pathway leading to the increase in DNA ligase I levels in response to anticancer drugs, including ara-C and aphidicolin. We propose that ara-C and aphidicolin induce damage to the DNA strand by arresting DNA replication forks and subsequently increase DNA ligase I levels to facilitate repair of DNA damage.

• Authors: Daekyu Sun, Rheanna Urrabaz, Christoph Buzello, Myhanh Nguyen
• Journal: Experimental cell research (Exp Cell Res) Vol. 280 Issue 1 Pg. 90-6 (Oct 15 2002) ISSN: 0014-4827 [Print] United States
• PMID: 12372342 (Publication Type: Comparative Study, Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Antimetabolites, Antineoplastic
• DNA, Neoplasm
• Enzyme Inhibitors
• LIG1 protein, human
• Nucleic Acid Synthesis Inhibitors
• Phosphodiesterase Inhibitors
• RNA, Messenger
• Cytarabine
• Aphidicolin
• Caffeine
• DNA-Directed DNA Polymerase
• DNA Ligases
• DNA Ligase ATP

Topics

• Antimetabolites, Antineoplastic (pharmacokinetics, pharmacology)
• Aphidicolin (pharmacokinetics, pharmacology)
• Caffeine (pharmacology)
• Cell Count
• Cell Division (drug effects)
• Cell Line
• Cell Survival (drug effects)
• Cytarabine (pharmacokinetics, pharmacology)
• DNA Ligase ATP
• DNA Ligases (biosynthesis, genetics)
• DNA Repair (drug effects)
• DNA, Neoplasm (biosynthesis)
• DNA-Directed DNA Polymerase (analysis)
• Dose-Response Relationship, Drug
• Enzyme Inhibitors (pharmacokinetics, pharmacology)
• Humans
• Nucleic Acid Synthesis Inhibitors (pharmacology)
• Pancreatic Neoplasms (enzymology, genetics, pathology)
• Phosphodiesterase Inhibitors (pharmacology)
• RNA, Messenger (metabolism)
• Tumor Cells, Cultured