Upregulation of p53 through induction of MDM2 degradation: improved potency through the introduction of an alkylketone sidechain on the anthraquinone core

Abstract

Overexpression of ubiquitin ligase MDM2 causes depletion of the p53 tumour-suppressor and thus leads to cancer progression. In recent years, anthraquinone analogs have received significant attention due to their ability to downregulate MDM2, thereby promoting p53-induced apoptosis. Previously, we have developed potent anthraquinone compounds having the ability to upregulate p53 via inhibition of MDM2 in both cell culture and animal models of acute lymphocytic leukaemia. Earlier work was focussed on mechanistic work, pharmacological validation of this class of compounds in animal models, and mapping out structural space that allows for further modification and optimisation. Herein, we describe our work in optimising the substituents on the two phenol hydroxyl groups. It was found that the introduction of an alkylketone moiety led to a potent series of analogs with BW-AQ-350 being the most potent compound yet (IC₅₀ = 0.19 ± 0.01 µM) which exerts cytotoxicity by inducing MDM2 degradation and p53 upregulation.

Keywords:

• p53
• MDM2
• anthraquinone
• cancer
• structure–activity relationship (SAR)

Acknowledgements

We also thank Dr. Gangli Wang for valuable discussion on the redox chemistry.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Financial support from the National Institutes of Health (CA180519) is gratefully acknowledged. We thank the Molecular Basis of Disease program for a graduate fellowship to R. Tripathi, the Center for Diagnostic and Therapeutics, for providing a CDT fellowship to A. Anifowose and internal resources at Georgia State University.