期刊
INTERNATIONAL JOURNAL OF CANCER
卷 129, 期 6, 页码 1425-1434出版社
WILEY-BLACKWELL
DOI: 10.1002/ijc.25814
关键词
chemoresistance; platinum chemotherapy; microdosing; accelerator mass spectrometry; DNA damage; DNA repair
类别
资金
- Gerry and Susan Knapp Family Fund
- National Institutes of Health
- American Cancer Society
- DOE [DE-AC52-07NA27344]
- NIH/NCRR [P41 RR013461]
- DOE LDRD [08-LW-100]
Formation and repair of platinum (Pt)-induced DNA adducts is a critical step in Pt drug-mediated cytotoxicity. Measurement of Pt-DNA adduct kinetics in tumors may be useful for better understanding chemoresistance and therapeutic response. However, this concept has yet to be rigorously tested because of technical challenges in measuring the adducts at low concentrations and consistent access to sufficient tumor biopsy material. Ultrasensitive accelerator mass spectrometry was used to detect [(14)C]carboplatin-DNA monoadducts at the attomole level, which are the precursors to Pt-DNA crosslink formation, in six cancer cell lines as a proof-of-concept. The most resistant cells had the lowest monoadduct levels at all time points over 24 hr. [(14)C] Carboplatin microdoses (1/100th the pharmacologically effective concentration) had nearly identical adduct formation and repair kinetics compared to therapeutically relevant doses, suggesting that the microdosing approach can potentially be used to determine the pharmacological effects of therapeutic treatment. Some of the possible chemoresistance mechanisms were also studied, such as drug uptake/efflux, intracellular inactivation and DNA repair in selected cell lines. Intracellular inactivation and efficient DNA repair each contributed significantly to the suppression of DNA monoadduct formation in the most resistant cell line compared to the most sensitive cell line studied (p < 0.001). Nucleotide excision repair (NER)-deficient and proficient cells showed substantial differences in carboplatin monoadduct concentrations over 24 hr that likely contributed to chemoresistance. The data support the utility of carboplatin microdosing as a translatable approach for defining carboplatin-DNA monoadduct formation and repair, possibly by NER, which may be useful for characterizing chemoresistance in vivo.
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