Abstract B015: Identification of novel natural compounds that induce DNA damage and chromosomal translocations

Abstract

Abstract Background: Etoposide is a well-characterized chemotherapeutic that promotes DNA double-strand breaks (DSBs) and is associated with therapy-related chromosomal translocations and leukemias. Natural compounds including bioflavonoids, which are found in food as well as in dietary supplements, have been shown by our lab to induce DSBs and promote genome rearrangements. Given the potential for bioflavonoids to cause these harmful effects, we are investigating the potential for a wide array of other natural compounds and environmental agents to also induce DNA DSBs and chromosomal translocations. The purpose of this study was to perform a high throughput screen on a National Institutes of Health (NIH) library of natural compounds to determine their ability to cause DSBs and chromosomal translocations and implicate them as risk factors for leukemias. Methods: We obtained 2 libraires from NIH containing over 2000 natural compounds. Mouse embryonic stem cells (mES) were exposed to individual compounds at 50mM for one hour. Following exposure, DNA damage was measured through γ-H2AX immunocytochemistry and microscopy to quantify the level of DNA damage induced in comparison to etoposide. Compounds identified to cause greater than or equal to 20% of the damage induced by etoposide were prioritized for study of their potential to induce chromosomal translocations. We developed a mES GFP Reporter cell line with engineered exons of GFP contained within MLL and AF9 breakpoint cluster region inserts. Cells were exposed to individual compounds at 50mM for one hour. Following exposure, cells were screened over 7 days for the generation of chromosomal translocation events as measured by appearance of GFP+ cells. Results: Exposure to the NIH natural compound library has thus far generated 22 hits with 5 - 20% the amount of damage caused by etoposide and 29 hits with greater than or equal to 20% of the damage of etoposide out of the 1,200 compounds tested thus far. Top “hits” include known inhibitors of topoisomerase I and II. Other top “hits” include natural compounds curcumin, illudin, prodigiosin, and predorine. Testing of the ability of these “hits” to cause chromosomal translocations are still underway, but compounds, such as curcumin, are showing translocation GFP+ events. Conclusions: Data from this study can be used to inform the public and doctors of natural compounds that may be believed to be beneficial for human health but that can actually cause DNA damage and potential translocations. This data could generate potential drug candidates useful in the treatment of cancer. Etoposide is known to create DSBs but it also causes frequent translocation events. This study could identify compounds that are able to cause DNA DSBs, essential to the destruction of cancer cells, with a lower likelihood of causing chromosomal translocation events in healthy cells. Citation Format: Donna Goodenow, Henry Thompson, Elizabeth Toufekoulas, Heather Derby, Christine Richardson. Identification of novel natural compounds that induce DNA damage and chromosomal translocations [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Damage Repair: From Basic Science to Future Clinical Application; 2024 Jan 9-11; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2024;84(1 Suppl):Abstract nr B015.