Development Of Phenyl 4-(2-Oxo-3-Alkylimidazolidin-1-Yl)Benzenesulfonates As New Antimitotic Cytochrome P450 1a1-Activated Prodrugs Selective Toward Breast Cancers: Evaluation Of Branched Alkyl Chains.

Abstract Enzyme-based prodrug treatments are innovative approaches that enable to convert a prodrug to a potent anticancer agent directly into the tumoral site. It is in this context that we recently discovered a new family of antimitotics that are CYP1A1-activated prodrugs referred to as phenyl 4-(2-oxo-3-alkylimidazolidin-1-yl)benzenesulfonates (PAIB-SOs). PAIB-SOs are highly selective toward breast cancer cells, exhibit antiproliferative activity in the nanomolar range, arrest the cell cycle progression in G2/M phase and disrupt the microtubule integrity. Further studies have evidenced that the selectivity of PAIB-SOs toward mammary cancer cells is related to their N-dealkylation into potent phenyl 4-(2-oxoimidazolidin-1-yl)-benzenesulfonates (PIB-SOs) by CYP1A1 directly into breast cancer cells. In this study, we designed and prepared new PAIB-SOs bearing N-branched alkyl chains on the imidazolidin-2-one moiety and evaluated their antiproliferative activity, selectivity toward breast cancer cells and finally their potential toxic effects. Antiproliferative activity was assessed using the sulforhodamine B method. PAIB-SO selectivity was determined using breast cancer cells expressing CYP1A1 (MCF7 and MDA-MB-468) and those not expressing it (MDA-MB-231). In addition, UHPLC-UV detection method was used to evaluate the CYP1A1-biotransformation of PAIB-SOs into their antimitotic PIB-SO counterparts. The mechanism of action of PAIB-SOs was studied by evaluating first, the cell cycle progression of MCF7 cells by flow cytometry and second the microtubules integrity by immunofluorescence staining. Finally, PAIB-SOs potential toxicity was assessed in vitro toward HaCat and HEK-293 primary cells and in ovo using the chick embryos model. PAIB-SOs bearing isopropyl and sec-butyl lose their selectivity toward breast cancer cells and show moderate antiproliferative activity (micromolar range). However, PAIB-SOs bearing an isobutyl group maintain their selectivity toward breast cancer cells expressing CYP1A1 and exhibit antiproliferative activity within the nanomolar range. In addition, enzymatic assays show that PAIB-SOs bearing an isobutyl group are metabolized into PIB-SOs in presence of CYP1A1 in contrast to isopropyl or sec-butyl substituted compounds. Moreover, our most potent PAIB-SOs arrest the cell cycle in the G2/M-phase and disrupt the cytoskeleton. Finally, HaCat and HEK-293 cells are unaffected by PAIB-SOs treatment which also exhibits a low toxicity toward the chick embryos. This study demonstrates that CYP1A1 can accommodate bulky groups and PAIB-SOs bearing an isobutyl group are potent new CYP1A1-activated prodrug derivatives exhibiting high selectivity toward breast cancer cells and low toxic effects. Citation Format: Chahrazed Bouzriba, Atziri Corin Chavez Alvarez, Mathieu Gagné-Boulet, Jacques Lacroix, Marie-France Côté, René C.-Gaudrault, Sébastien Fortin. Development of phenyl 4-(2-oxo-3-alkylimidazolidin-1-yl)benzenesulfonates as new antimitotic cytochrome P450 1A1-activated prodrugs selective toward breast cancers: Evaluation of branched alkyl chains [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 285.