Abstract 4009: Biotinylated estrogens a novel tool for early detection of adduct in ovarian cancer and their carcinogenic effects in cultured human cells

Abstract

Abstract In humans, endogenous estrogens such as Estrone (E1) and 17L-estradiol (E2) regulate many physiological processes including reproduction, primarily in females, and control the growth of certain responsive cells. However, unbalanced estrogen metabolism has been linked to development of several malignant diseases including breast, endometrial and ovarian cancer and has been identified as a risk factor for these cancers. Elevated estrogens exert their carcinogenic effects by at least three different mechanisms; they promote cell proliferation by transcriptional regulation of estrogen responsive genes, cause generation of reactive oxygen species and other free radicals, and directly react with DNA and form potentially mutagenic adducts. The metabolic breakdown of estogens is regulated by a series of reactions mediated by hepatic and peripheral enzymes that balances the induction and reduction of cellular stress. An imbalance in this enzymes and processes can lead to highly reactive catechol estrogen metabolites that can react with DNA, form carcinogenic DAN-adducts and lesions. Although several studies established a connection between estrogen-induced DNA damage and carcinogenesis, the underlying molecular mechanisms have been difficult to study because of the technical challenges in detecting and analyzing the variety of different DNA lesions that are formed by estrogen compounds. Moreover, detection and analysis of these adducts are important to directly monitor estrogen metabolites induced cellular responses in the cells. Towards this, we developed a novel method using biotinylated-estrogens that allows immunodetection of estrogen-induced DNA adducts by Slot-blot and single-cell molecular combing and proximity ligation assays. Using these modified estrogens we first time quantitatively detected these adducts on DNA by immune Slot-blot techniques and on DNA fibers. Furthermore, similar to other environmental carcinogens estrogens activates replication associated DNA damage responses and induces chromosomal instability. Thus, for the first time our studies demonstrate that biotin-labeled estrogens could be a powerful tool to detect estrogen adducts and to probe associated DNA damage responses and cellular responses. Citation Format: Kaushlendra Tripathi. Biotinylated estrogens a novel tool for early detection of adduct in ovarian cancer and their carcinogenic effects in cultured human cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4009.