Journal article
Characterization of Protein Kinase chk1 Essential for the Cell Cycle Checkpoint after Exposure of Human Head and Neck Carcinoma A253 Cells to a Novel Topoisomerase I Inhibitor BNP1350
Molecular pharmacology, Vol.57(3), pp.453-459
03/01/2000
DOI: 10.1124/mol.57.3.453
PMID: 10692484
Abstract
Cellular topoisomerase I is an important target in cancer chemotherapy. A novel karenitecin, BNP1350, is a topoisomerase I-targeting anticancer agent with significant antitumor activity against human head and neck carcinoma A253 cells in vitro. As a basis for future clinical trials of BNP1350 in human head and neck carcinoma, in vitro studies were carried out to investigate its effect on DNA damage and cell cycle checkpoint response. The treatment of A253 cells with BNP1350 caused biphasic profiles of DNA fragmentation displayed from 0 to 48 h after 2-h exposure. Pulsed-field gel electrophoresis demonstrated that the first wave of DNA damage was mainly megabase DNA fragmentation, but the second wave of DNA damage was 50- to 300- kb DNA fragmentation in addition to megabase DNA damage. The cell cycle checkpoint response was characterized after exposure to 0.07 and 0.7 μM concentrations of BNP1350, the IC50 and IC90 values, respectively. After exposure to a low concentration of BNP1350 (IC50), A253 cells accumulated primarily in G2 phase. In contrast, treatment with a high concentration of BNP1350 (IC90) resulted in S phase accumulation. The concentration- associated cell cycle perturbation by BNP1350 was correlated with different profiles of cell cycleregulatory protein expression. When treated with the low concentration of BNP1350, cyclin B/cdc2 protein expression was up- regulated, whereas with the high concentration, no significant change was observed at 24 and 48 h. In addition, increased phosphorylation of a G2 checkpoint kinase chk1 was observed when cells were treated with a low concentration of BNP1350, whereas only slight inhibition of chk1 activity was found in the cells treated with the higher concentration. Altered chk1 phosphorylation after DNA damage appears to be associated with specific phases of cell cycle arrest induced by BNP1350. Because A253 cells do not express the p53 protein, the drug-induced alterations of the G2 checkpoint kinase chk1 are not p53-dependent.
Details
- Title: Subtitle
- Characterization of Protein Kinase chk1 Essential for the Cell Cycle Checkpoint after Exposure of Human Head and Neck Carcinoma A253 Cells to a Novel Topoisomerase I Inhibitor BNP1350
- Creators
- Ming-Biao Yin - Roswell Park Cancer InstituteBin Guo - Roswell Park Cancer InstituteUdo Vanhoefer - Roswell Park Cancer InstituteRami G. Azrak - Roswell Park Cancer InstituteHans Minderman - Roswell Park Cancer InstituteCheryl Frank - Roswell Park Cancer InstituteCarol Wrzosek - Roswell Park Cancer InstituteHarry K. Slocum - Roswell Park Cancer InstituteYoucef M. Rustum - Roswell Park Cancer Institute
- Resource Type
- Journal article
- Publication Details
- Molecular pharmacology, Vol.57(3), pp.453-459
- DOI
- 10.1124/mol.57.3.453
- PMID
- 10692484
- ISSN
- 0026-895X
- eISSN
- 1521-0111
- Language
- English
- Date published
- 03/01/2000
- Academic Unit
- Hematology, Oncology, and Blood & Marrow Transplantation; Internal Medicine
- Record Identifier
- 9984359916302771
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