engleski

Development of ribonuclease H2A inhibitors as anticancer agents

Introduction: While patients with advanced cancers may initially respond to chemotherapy, they are rarely cured and most of them ultimately relapse and die [1]. As the effects of chemotherapy and radiation on cancer cells likely occur through induction of DNA damage, resistance to genotoxic agents in advanced cancer might be associated with factors governing DNA break repair, chromatin structure and genome stability. Previously, we and others had identified ribonucleases H as factors strongly associated with both increased chromosomal breaks and loss [2]. Recent evidence has demonstrated RNASEH2A overexpression in different solid cancers [3]. Furthermore, latest bioinformatic studies determined RNASEH2A among the top 2% of targets for cancer drug development. To this end we aimed to develop RNASEH2A inhibitors. Methods: We utilized a fluorescence resonance energy transfer assay for high-throughput screening of inhibitors of RNASEH2A activity. More than 2000 compounds from NCI chemical libraries were screened with this assay. The Ki’s of each inhibitor were determined by using the GraphPad Prism Program. In order to assess the role of RNASEH2A in tumor survival we treated several cancer cell lines with different levels of RNASEH2A expression (MV4-11, HL-60, HeLa) with increasing concentrations of several RNASEH2A inhibitors for 0, 4, 24, 48 and 72 h. The effects on cell viability, apoptosis and cell cycle were assessed by using standard assays. Results: About 70 inhibitors were uncovered, most of which show relatively high potency and high specificity. RNASEH2A inhibitors affected the viability of cell lines with high levels of RNASEH2A expression. No effect was observed in HeLa cell line with low or no RNASEH2A expression.

ribonuclease H2A inhibitors ; anticancer agents

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