Monitoring Drug-Induced γH2AX as a Pharmacodynamic Biomarker in Individual Circulating Tumor Cells
- 1 February 2010
- journal article
- Published by American Association for Cancer Research (AACR) in Clinical Cancer Research
- Vol. 16 (3), 1073-1084
- https://doi.org/10.1158/1078-0432.ccr-09-2799
Abstract
Purpose: Circulating tumor cells (CTC) in peripheral blood of patients potentially represent a fraction of solid tumor cells available for more frequent pharmacodynamic assessment of drug action than is possible using tumor biopsy. However, currently available CTC assays are limited to cell membrane antigens. Here, we describe an assay that directly examines changes in levels of the nuclear DNA damage marker γH2AX in individual CTCs of patients treated with chemotherapeutic agents. Experimental Design: An Alexa Fluor 488–conjugated monoclonal γH2AX antibody and epithelial cancer cell lines treated with topotecan and spiked into whole blood were used to measure DNA damage–dependent nuclear γH2AX signals in individual CTCs. Time-course changes in both CTC number and γH2AX levels in CTCs were also evaluated in blood samples from patients undergoing treatment. Results: The percentage of γH2AX-positive CTCs increased in a concentration-dependent manner in cells treated with therapeutically relevant concentrations of topotecan ex vivo. In samples from five patients, percent γH2AX-positive cells increased post-treatment from a mean of 2% at baseline (range, 0-6%) to a mean of 38% (range, 22-64%) after a single day of drug administration; this increase was irrespective of increases or decreases in the total CTC count. Conclusions: These data show promise for monitoring dynamic changes in nuclear biomarkers in CTCs (in addition to CTC count) for rapidly assessing drug activity in clinical trials of molecularly targeted anticancer therapeutics as well as for translational research. Clin Cancer Res; 16(3); 1073–84Keywords
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This publication has 40 references indexed in Scilit:
- Circulating Tumor Cells in Patients with Castration-Resistant Prostate Cancer Baseline Values and Correlation with Prognostic FactorsCancer Epidemiology, Biomarkers & Prevention, 2009
- Anti-Epithelial Cell Adhesion Molecule Antibodies and the Detection of Circulating Normal-Like Breast Tumor CellsJNCI Journal of the National Cancer Institute, 2009
- Transcription-coupled DNA Double-Strand Breaks Are Mediated via the Nucleotide Excision Repair and the Mre11-Rad50-Nbs1 ComplexMolecular Biology of the Cell, 2008
- Detection of Mutations inEGFRin Circulating Lung-Cancer CellsThe New England Journal of Medicine, 2008
- American Society of Clinical Oncology 2007 Update of Recommendations for the Use of Tumor Markers in Breast CancerJournal of Clinical Oncology, 2007
- An optimized method for detecting gamma-H2AX in blood cells reveals a significant interindividual variation in the gamma-H2AX response among humansNucleic Acids Research, 2007
- Circulating Tumor Cells at Each Follow-up Time Point during Therapy of Metastatic Breast Cancer Patients Predict Progression-Free and Overall SurvivalClinical Cancer Research, 2006
- Circulating Tumor Cells: A Novel Prognostic Factor for Newly Diagnosed Metastatic Breast CancerJournal of Clinical Oncology, 2005
- Circulating Tumor Cells, Disease Progression, and Survival in Metastatic Breast CancerThe New England Journal of Medicine, 2004
- HER-2 gene amplification can be acquired as breast cancer progressesProceedings of the National Academy of Sciences of the United States of America, 2004