Abstract 3092: Optimization of deferiprone for the treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the leading cause of new cancer cases and the second leading cause of cancer deaths in American women. TNBC is one of the most difficult cancers to treat due to the lack of three receptors, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (HER2), found in regular forms of breast cancer (BCa). Currently, there is no targeted therapy for TNBC and treatment options to manage this lethal disease include surgery, adjuvant chemotherapy and radiotherapy. A better understanding of TNBC etiology has aided in unraveling the roles of two additional cellular targets - androgen receptor (AR) and histone lysine demethylase (KDM) - in the viability and survival of TNBC. Interestingly, AR overexpression is the most important driver of prostate cancer (PCa). A class of current medications used to treat PCa act as androgen receptor (AR) antagonists (or antiandrogens). It is therefore plausible to repurpose and optimize these antiandrogens for TNBC therapy. The proposed therapeutics are dual-acting antiandrogen-KDM inhibitors. The antiandrogen moiety of these agents will enable TNBC cell-targeting and translocation of the drug into the nucleus where inhibition of KDM will prevent transcription of KDMs that promote tumor. The three pharmacophores of these agents are (i) a surface recognition cap, (ii) a linker, and (iii) an Fe2+-binding group. Two classes of these compounds, alkyl-derivative and benzyl-derivative, vary in the design of the surface recognition cap. To optimize these agents, the linker length is varied from 2-7 methylene groups in each class and the optimal length will be determined through in vitro studies. The compounds are tested on five cancer cell lines: TNBC cell lines (MDA-MB-231, low AR+; and MDA-MB-453, high AR+), and ER+ BCa (MCF-7) while PCa cell lines (LNCaP PCa, AR+; and DU 145, PCa, AR-) serve as controls for AR dependency of the effects of test compounds. Longer linker length compounds exhibited low micromolar cytotoxicity and selectivity for MDA-MB-231 (TNBC) and LNCaP (PCa) cell lines due to the presence of the AR. Western blot analysis on lead compounds supported significant downregulation of AR in MDA-MB-231 cells confirming the predicted mechanism of action. Thus far, the designed dual-acting therapeutics have potential to revolutionize the design of anticancer drugs and improve treatment outcome for TNBC patients. Citation Format: Alexis Johnston, Adegboye