Biological Effects of HDAC Inhibitors Vary with Zinc Binding Group: Differential Effects on Zinc Bioavailability, ROS Production, and R175H p53 Mutant Protein Reactivation

Brianna M Flores; Chandana K Uppalapati; Agnes S Pascual; Alan Vong; Margaux A Baatz; Alisha M Harrison; Kathryn J Leyva; Elizabeth E Hull

doi:10.3390/biom13111588

Biological Effects of HDAC Inhibitors Vary with Zinc Binding Group: Differential Effects on Zinc Bioavailability, ROS Production, and R175H p53 Mutant Protein Reactivation

Biomolecules. 2023 Oct 28;13(11):1588. doi: 10.3390/biom13111588.

Authors

Brianna M Flores^{1

2}, Chandana K Uppalapati³, Agnes S Pascual¹, Alan Vong¹, Margaux A Baatz¹, Alisha M Harrison¹, Kathryn J Leyva³, Elizabeth E Hull¹

Affiliations

¹ Biomedical Sciences Program, College of Graduate Studies, Midwestern University, 19555 N 59th Avenue, Glendale, AZ 85308, USA.
² Arizona College of Osteopathic Medicine, Midwestern University, 19555 N 59th Avenue, Glendale, AZ 85308, USA.
³ Department of Microbiology & Immunology, College of Graduate Studies, Midwestern University, 19555 N 59th Avenue, Glendale, AZ 85308, USA.

Abstract

The coordination of zinc by histone deacetylase inhibitors (HDACi), altering the bioavailability of zinc to histone deacetylases (HDACs), is key to HDAC enzyme inhibition. However, the ability of zinc binding groups (ZBGs) to alter intracellular free Zn⁺² levels, which may have far-reaching effects, has not been explored. Using two HDACis with different ZBGs, we documented shifts in intracellular free Zn⁺² concentrations that correlate with subsequent ROS production. Next, we assayed refolding and reactivation of the R175H mutant p53 protein in vitro to provide greater biological context as the activity of this mutant depends on cellular zinc concentration. The data presented demonstrates the differential activity of HDACi in promoting R175H response element (RE) binding. After cells are treated with HDACi, there are differences in R175H mutant p53 refolding and reactivation, which may be related to treatments. Collectively, we show that HDACis with distinct ZBGs differentially impact the intracellular free Zn⁺² concentration, ROS levels, and activity of R175H; therefore, HDACis may have significant activity independent of their ability to alter acetylation levels. Our results suggest a framework for reevaluating the role of zinc in the variable or off-target effects of HDACi, suggesting that the ZBGs of HDAC inhibitors may provide bioavailable zinc without the toxicity associated with zinc metallochaperones such as ZMC1.

Keywords: HDAC inhibitors; R175H mutant p53; ROS production; p53 reactivation; zinc bioavailability.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Biological Availability
Histone Deacetylase Inhibitors* / pharmacology
Reactive Oxygen Species / metabolism
Tumor Suppressor Protein p53 / genetics
Tumor Suppressor Protein p53 / metabolism
Zinc* / metabolism

Substances

Histone Deacetylase Inhibitors
Reactive Oxygen Species
Zinc
Tumor Suppressor Protein p53

Grants and funding

This research was funded by intramural funds provided by Midwestern University. E.E.H. and K.J.L. received intramural funding from Midwestern University. B.M.F., A.V., and M.A.B. received funding from the Midwestern University Biomedical Sciences Program. B.M.F. was supported by a Midwestern University KAS Fellowship.