Abstract
Lysosomes act as a cellular drug sink for weakly basic, lipophilic (lysosomotropic) xenobiotics, with many instances of lysosomal trapping associated with multiple drug resistance. Lysosomotropic agents have also been shown to activate master lysosomal biogenesis transcription factor EB (TFEB) and ultimately lysosomal biogenesis. We investigated the role of lysosomal biogenesis in the disposition of hydroxychloroquine (HCQ), a hallmark lysosomotropic agent, and observed that modulating the lysosomal volume of human breast cancer cell lines can account for differences in disposition of HCQ. Through use of an in vitro pharmacokinetic (PK) model, we characterized total cellular uptake of HCQ within the duration of static equilibrium (1 hour), as well as extended exposure to HCQ that is subject to dynamic equilibrium (>1 hour), wherein HCQ increases the size of the lysosomal compartment through swelling and TFEB-induced lysosomal biogenesis. In addition, we observe that pretreatment of cell lines with TFEB-activating agent Torin1 contributed to an increase of whole-cell HCQ concentrations by 1.4- to 1.6-fold, which were also characterized by the in vitro PK model. This investigation into the role of lysosomal volume dynamics in lysosomotropic drug disposition, including the ability of HCQ to modify its own disposition, advances our understanding of how chemically similar agents may distribute on the cellular level and examines a key area of lysosomal-mediated multiple drug resistance and drug-drug interaction.
Significance Statement Hydroxychloroquine is able to modulate its own cellular pharmacokinetic uptake by increasing the cellular lysosomal volume fraction through activation of lysosomal biogenesis master transcription factor EB and through lysosomal swelling. This concept can be applied to many other lysosomotropic drugs that activate transcription factor EB, such as doxorubicin and other tyrosine kinase inhibitor drugs, as these drugs may actively increase their own sequestration within the lysosome to further exacerbate multiple drug resistance and lead to potential acquired resistance.
Footnotes
- Received August 28, 2020.
- Accepted October 26, 2020.
This work was supported by National Institutes of Health National Cancer Institute [Grant R01CA190170] (Therapeutic Targeting of Autophagy-Dependent Cancer) and [Grant P30CA046934](University of Colorado Cancer Center Support Grant, Pharmacology Shared Resource), by Department of Defense Congressionally Directed Medical Research Program Breast Cancer Research Program [Grant BC130103P1] (Identifying and Targeting Autophagy Dependence to Eliminate Metastatic Breast Cancer), and by the Shipley University Chair in Comparative Oncology [DL Gustafson].
The authors declare that no conflict of interest exists.
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This article has supplemental material available at jpet.aspetjournals.org.
- Copyright © 2021 by The American Society for Pharmacology and Experimental Therapeutics
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Lysosomal Biogenesis and Hydroxychloroquine Disposition
