John E. Kerrigan

Bio: John E. Kerrigan is an academic researcher from Rutgers University. The author has contributed to research in topics: Topoisomerase & Receptor. The author has an hindex of 19, co-authored 39 publications receiving 1572 citations. Previous affiliations of John E. Kerrigan include University of Medicine and Dentistry of New Jersey.

Topoisomerase IIβ–Mediated DNA Double-Strand Breaks: Implications in Doxorubicin Cardiotoxicity and Prevention by Dexrazoxane

Abstract: Doxorubicin is among the most effective and widely used anticancer drugs in the clinic. However, cardiotoxicity is one of the life-threatening side effects of doxorubicin-based therapy. Dexrazoxane (Zinecard, also known as ICRF-187) has been used in the clinic as a cardioprotectant against doxorubicin cardiotoxicity. The molecular basis for doxorubicin cardiotoxicity and the cardioprotective effect of dexrazoxane, however, is not fully understood. In the present study, we showed that dexrazoxane specifically abolished the DNA damage signal gamma-H2AX induced by doxorubicin, but not camptothecin or hydrogen peroxide, in H9C2 cardiomyocytes. Doxorubicin-induced DNA damage was also specifically abolished by the proteasome inhibitors bortezomib and MG132 and much reduced in top2beta(-/-) mouse embryonic fibroblasts (MEF) compared with TOP2beta(+/+) MEFs, suggesting the involvement of proteasome and DNA topoisomerase IIbeta (Top2beta). Furthermore, in addition to antagonizing Top2 cleavage complex formation, dexrazoxane also induced rapid degradation of Top2beta, which paralleled the reduction of doxorubicin-induced DNA damage. Together, our results suggest that dexrazoxane antagonizes doxorubicin-induced DNA damage through its interference with Top2beta, which could implicate Top2beta in doxorubicin cardiotoxicity. The specific involvement of proteasome and Top2beta in doxorubicin-induced DNA damage is consistent with a model in which proteasomal processing of doxorubicin-induced Top2beta-DNA covalent complexes exposes the Top2beta-concealed DNA double-strand breaks.

A Structural Model for the Ternary Cleavable Complex Formed between Human Topoisomerase I, DNA, and Camptothecin†

Abstract: Using the X-ray crystal structure of the human topoisomerase I (TOP1)-DNA cleavable complex, we have developed a general model for the ternary drug-DNA-TOP1 cleavable complex formed with camptothecin (CPT) and its analogues. This model has the drug intercalated between the -1 and +1 base pairs, with the E-ring pointing into the minor groove and the A-ring directed toward the major groove. The ternary complex is stabilized by an array of hydrogen bonding and hydrophobic interactions between the drug and both the enzyme and the DNA. Significantly, the proposed model is consistent with the current body of experimental mutation, cross-linking, and structure-activity data. In addition, the model reveals potential sites of interaction that can provide a rational basis for the design of next generation compounds as well as for de novo drug design.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Targeting DNA topoisomerase II in cancer chemotherapy

Abstract: Recent molecular studies have expanded the biological contexts in which topoisomerase II (TOP2) has crucial functions, including DNA replication, transcription and chromosome segregation. Although the biological functions of TOP2 are important for ensuring genomic integrity, the ability to interfere with TOP2 and generate enzyme-mediated DNA damage is an effective strategy for cancer chemotherapy. The molecular tools that have allowed an understanding of the biological functions of TOP2 are also being applied to understanding the details of drug action. These studies promise refined targeting of TOP2 as an effective anticancer strategy.

Identification of the molecular basis of doxorubicin-induced cardiotoxicity

Abstract: Doxorubicin is believed to cause dose-dependent cardiotoxicity through redox cycling and the generation of reactive oxygen species (ROS). Here we show that cardiomyocyte-specific deletion of Top2b (encoding topoisomerase-IIβ) protects cardiomyocytes from doxorubicin-induced DNA double-strand breaks and transcriptome changes that are responsible for defective mitochondrial biogenesis and ROS formation. Furthermore, cardiomyocyte-specific deletion of Top2b protects mice from the development of doxorubicin-induced progressive heart failure, suggesting that doxorubicin-induced cardiotoxicity is mediated by topoisomerase-IIβ in cardiomyocytes.

Doxorubicin pathways: pharmacodynamics and adverse effects

Abstract: The goal of this study is to give a brief background on the literature supporting the PharmGKB pathway about doxorubicin action, and provides a summary of this active area of research. The reader is referred to recent in-depth reviews [1–4] for more detailed discussion of this important and complex pathway. Doxorubicin is an anthracyline drug first extracted from Streptomyces peucetius var. caesius in the 1970’s and routinely used in the treatment of several cancers including breast, lung, gastric, ovarian, thyroid, non-Hodgkin’s and Hodgkin’s lymphoma, multiple myeloma, sarcoma, and pediatric cancers [5–7]. A major limitation for the use of doxorubicin is cardiotoxicity, with the total cumulative dose being the only criteria currently used to predict the toxicity [4,8]. As there is evidence that the mechanisms of anticancer action and of cardiotoxicity occur through different pathways there is hope for the development of anthracycline drugs with equal efficacy but reduced toxicity [4]. Knowledge of the pharmacogenomics of these pathways may eventually allow for future selection of patients more likely to achieve efficacy at lower doses or able to withstand higher doses with lesser toxicity. We present here graphical representations of the candidate genes for the pharmacogenomics of doxorubicin action in a stylized cancer cell (Fig. 1) and toxicity in cardiomyocytes (Fig. 2), and a table describing the key variants examined so far. Open in a separate window Fig. 1 Graphical representation of the candidate genes involved in the pharmacodynamics of doxorubicin in a stylized cancer cell. A fully interactive version of this pathway is available online at PharmGKB at http://www.pharmgkb.org/do/serve?objId=PA165292163o ROS, reactive oxygen species.