DNA Biomarkers Antecede Semiquantitative Anthracycline Cardiomyopathy

Abstract

Adriamycin (ADM, or doxorubicin hydrochloride) is an effective antineoplastic agent whose use is restricted by its well-described, dose-dependent cardiotoxicity. This study measures ADM DNA adduct formation by 32P-radiolabeling DNA, enzymatically digesting radiolabeled DNA, separating the formed adducts on two-dimensional thinlayer chromatography (2D-TLC), and quantitating the adducts with autoradiography and densitometry. Thirty-six male Sprague-Dawley rats are randomized to receive ADM at varying intraperitoneal (i.p.) injection concentrations: 0.9% saline i.p. controls, 4 mg/kg ADM i.p., and 6 mg/kg ADM i.p. Myocardial and pulmonary tissues are harvested 48 hours after i.p. injection for autoradiographic and histopathologic analyses. The results indicate differences in the amount and type of adduct formation as a function of ADM concentration. Increased partial depurination of dGMP and dAMP occurs with increasing ADM concentration at equal incubation times. This depurination correlates with the emergence of new adducts HM-dUMP, 8-OH-dGMP, HM-dCMP, and Me-dCMP. The quantification of these adducts can potentially represent an early marker of ADM cardiotoxicity and thereby optimize the efficacy of individual chemotherapy regimens while minimizing adverse effects.

Oxidative Damage Precedes Nitrative Damage in Adriamycin-Induced Cardiac Mitochondrial Injury

“…Quantification of ADR-DNA adducts formation by 32 P-radiolabeled DNA has been demonstrated to be an early marker of ADR-induced cardiotoxicity (Hahm et al, 2003). Histological and ultrastructural studies have shown alterations in nucleoli after treatment with ADR, including nucleolar segregation, nucleolar fragmentation, and conversion of nucleoli to a ring shape (Merski et al, 1976(Merski et al, , 1978.…”

“…ADR has been demonstrated to exert a multiplicity of effects on myocardial nuclei. Quantification of ADR-DNA adducts formation by 32 P-radiolabeled DNA has been demonstrated to be an early marker of ADR-induced cardiotoxicity (Hahm et al, 2003). Histological and ultrastructural studies have shown alterations in nucleoli after treatment with Vol.…”

Protecting the heart in cancer therapy

“…Likewise, many other predictive biomarker strategies are currently being developed in the preclinical arena. Proteomics 144 and metabolomics 145 pattern diagnostics, as well as transcriptome profiling 146 , have been shown to be useful in animal models of AIC as well as the detection of doxorubicin DNA adducts (HM-dUMP, 8-OH-dGMP, HM-dCMP, and Me-dCMP) 136 and other particular genes that are overexpressed during incipient cardiotoxicity 137 . Cellular proteins such as S100A1 141 , cMLC1 142 , and cathepsin B 143 have also been shown to have predictive value.…”

Alternative Biomarkers for Combined Biology

“…Depurination of dGMP and dAMP occurs in parallel with increasing ADM concentration, enabling the quantification of the formed DNA adducts even at low doses of doxorubicin. 60 It is conceivable that analysis from more accessible tissue (e.g., skeletal muscle lymph nodes) surrogating doxorubicin-exposed myocardium may make this diagnostic approach feasible in the near future, but its predictive value remains to be determined.…”