Project description:The anthracycline doxorubicin is a highly effective anti-cancer drug associated with severe side effects, including secondary tumors and cardiotoxicity. Doxorubicin induces DNA damage through double-strand breaks (DSBs) and epigenetic or chromatin damage through histone eviction. We examined whether separation of these activities can help to detoxify doxorubicin, while maintaining its chemotherapeutic efficacy. We show that anthracycline variants harboring the histone eviction activity alone remain potent anti-cancer drugs, while greatly alleviating cardiotoxicity and secondary tumor formation. We thus demonstrate that treatment-limited side effects of doxorubicin can be synthesized away, yielding effective chemotherapeutics towards improved and prolonged treatment responses and higher patient quality of life.
Project description:We use a metabolic labeling strategy for directly measuring nucleosome turnover to examine the effect of doxorubicin on chromatin dynamics in squamous cell carcinoma cell lines derived from genetically defined mice. We find that doxorubicin enhances nucleosome turnover around gene promoters, and turnover correlates with gene expression level. Keywords: Chromatin affinity-purification on microarray
Project description:Objective: To assess the role of aldoketoreductases and other doxorubicin pharmacokinetic or pharmacogenomic genes in doxorubicin cytotoxicity, resistance, DNA binding activity, and subcellular localization, Methods: We conducted a whole genome microarray study to identify differences in between doxorubicin-sensitive MCF-7cc cells and doxorubicin-resistant MCF-7Dox2-12 cells in terms of their expression of genes related to doxorubicin pharmacokinetics or pharmacodynamics. Targets were then validated by pharmacologic inhibition in conjunction with drug metabolite profiling, drug localization, drug cytotoxicity, and drug DNA binding studies. Results: 2063 differentially expressed transcripts were identified, including 17% and 43% of genes or gene families associated with doxorubicin pharmacokinetics or pharmacodynamics (p values of significance of 0.05 and <0.0001, respectively). The largest changes in the expression of genes associated with doxorubicin pharmacokinetics and pharmacodynamics were chiefly among the aldo-keto reductases (AKRs) Akr1c2, Akr1c3 and Akr1b10 which convert doxorubicin to doxorubicinol. We observed that doxorubicinol exhibits dramatically reduced drug toxicity, reduced drug DNA-binding activity, and altered drug subcellular localization to lysosomes. Pharmacologic inhibition of these AKRs in MCF-7Dox2-12 cells restored drug cytotoxicity, and drug localization to the nucleus. Conclusion: These findings demonstrate the utility of using curated pharmacokinetic and pharmacodynamic knowledgebases to identify highly relevant genes associated with doxorubicin resistance. The products of one or more of these genes could effectively be shown to alter the drug’s properties, while inhibiting them restored drug DNA binding, cytotoxicity, and subcellular localization.
Project description:The goal of this study is to identify nucleosome occupancies in leukemic cells treated with either HDAC inhibitor or doxorubicin or HDAC inhibitor plus doxorubicin
Project description:Objective: To assess the role of aldoketoreductases and other doxorubicin pharmacokinetic or pharmacogenomic genes in doxorubicin cytotoxicity, resistance, DNA binding activity, and subcellular localization, Methods: We conducted a whole genome microarray study to identify differences in between doxorubicin-sensitive MCF-7cc cells and doxorubicin-resistant MCF-7Dox2-12 cells in terms of their expression of genes related to doxorubicin pharmacokinetics or pharmacodynamics. Targets were then validated by pharmacologic inhibition in conjunction with drug metabolite profiling, drug localization, drug cytotoxicity, and drug DNA binding studies. Results: 2063 differentially expressed transcripts were identified, including 17% and 43% of genes or gene families associated with doxorubicin pharmacokinetics or pharmacodynamics (p values of significance of 0.05 and <0.0001, respectively). The largest changes in the expression of genes associated with doxorubicin pharmacokinetics and pharmacodynamics were chiefly among the aldo-keto reductases (AKRs) Akr1c2, Akr1c3 and Akr1b10 which convert doxorubicin to doxorubicinol. We observed that doxorubicinol exhibits dramatically reduced drug toxicity, reduced drug DNA-binding activity, and altered drug subcellular localization to lysosomes. Pharmacologic inhibition of these AKRs in MCF-7Dox2-12 cells restored drug cytotoxicity, and drug localization to the nucleus. Conclusion: These findings demonstrate the utility of using curated pharmacokinetic and pharmacodynamic knowledgebases to identify highly relevant genes associated with doxorubicin resistance. The products of one or more of these genes could effectively be shown to alter the drug’s properties, while inhibiting them restored drug DNA binding, cytotoxicity, and subcellular localization. Doxorubicin resistant cell lines of breast MCF-7 cells were generated for gene expression profilling. Two colour microarray of Agilent whole human genome nucleotide arrays was conducted with four labelling replicates of both forward and reverse labellings plus another set of 8 arrays with forward labelling. Sixteen arrays were used for this experiments. The co-cultured control cells MCF-7cc12 was generated by parallel selection process in the absence of drug.
Project description:Doxorubicin (Dox) is an effective chemotherapeutic agent against a broad range of tumors. However, a threshold dose of doxorubicin causes an unacceptably high incidence of heart failure and limits its clinical utility. We have established two models of doxorubicin cardiotoxicity in mice: 1) in an acute model, mice are treated with 15mg/kg of doxorubicin once; 2) in a chronic model, they receive 3mg/kg weekly for the first 12 of a total of 18 weeks. Using echocardiography, we have monitored left ventricular function of the mouse hearts during treatment in chronic model and seen the expected development of dilated cardiomyopathy (DCM). Treated mice showed histological abnormalities similar to those seen in patients with doxorubicin cardiomyopathy. To investigate transcriptional regulation in these models, we used a microarray we generated with over 5000 independent cDNA clones from murine heart and skeletal muscle. We have identified genes that respond to doxorubicin exposure in both model systems, and confirmed these results using real-time PCR. In the acute model, a set of genes is regulated early and rapidly returns to baseline levels, consistent with the half-life of doxorubicin. In the chronic model, which mimics the clinical situation much more closely, we identified dysregulated genes that implicate specific mechanisms of cardiac toxicity and may serve as biomarkers of doxorubicin induced dilated cardiomyopathy. Keywords: time course
Project description:Doxorubicin is a commonly used anticancer agent that can cause debilitating and irreversible cardiac injury. The initiating mechanisms contributing to this side effect remain unknown, and current preventative strategies only offer modest protection. Using stem cell-derived cardiomyocytes from patients receiving doxorubicin, we probed the transcriptomic landscape of solute carriers and identified OCT3 (SLC22A3) as a critical transporter regulating the cardiac accumulation of doxorubicin. Functional validation studies in mice revealed that targeting OCT3 can attenuate cardiac dysfunction without compromising the anticancer properties of doxorubicin. These findings provide a rationale for the development of targeted approaches to mitigate this debilitating toxicity