New insights into the intracellular distribution pattern of cationic amphiphilic drugs

Abstract

Cationic amphiphilic drugs (CADs) comprise a wide variety of different substance classes such as antidepressants, antipsychotics, and antiarrhythmics. It is well recognized that CADs accumulate in certain intracellular compartments leading to specific morphological changes of cells. So far, no adequate technique exists allowing for ultrastructural analysis of CAD in intact cells. Azidobupramine, a recently described multifunctional antidepressant analogue, allows for the first time to perform high-resolution studies of CADs on distribution pattern and morphological changes in intact cells. We showed here that the intracellular distribution pattern of azidobupramine strongly depends on drug concentration and exposure time. The mitochondrial compartment (mDsRed) and the late endo-lysosomal compartment (CD63-GFP) were the preferred localization sites at low to intermediate concentrations (i.e. 1 μM, 5 μM). In contrast, the autophagosomal compartment (LC3-GFP) can only be reached at high concentrations (10 μM) and long exposure times (72 hrs). At the morphological level, LC3-clustering became only prominent at high concentrations (10 μM), while changes in CD63 pattern already occurred at intermediate concentrations (5 μM). To our knowledge, this is the first study that establishes a link between intracellular CAD distribution pattern and morphological changes. Therewith, our results allow for gaining deeper understanding of intracellular effects of CADs.

Psychotropic Drugs Show Anticancer Activity by Disrupting Mitochondrial and Lysosomal Function

“…Finally, all psychotropic compounds with cationic amphiphilic properties caused a significant reduction in ψm. Since oncogenic activation leads to increased mitochondrial metabolism and higher ψm compared to that of noncancer cells (20) and experimental evidence demonstrates that irreversible mitochondrial membrane depolarization can induce cell death also in apoptotic resistant cells (84), CADs appear excellent candidates for mitochondrial targeting in cancer, as they can easily diffuse in tumor tissues and interact with negatively charged mitochondrial membranes (20,45,49). Since in our cell line model cytotoxicity of psychotropic drugs was not mediated by ROS and thiols oxidation whereas apoptosis has been demonstrated only in cells treated with spiperone, studies are underway to explore the molecular mechanisms underlying CADs induced mitochondrial membrane depolarization and its role in inducing cancer cell death.…”

“…These compounds contain both a hydrophobic and a hydrophilic domain; the hydrophobic domain contains one or more aromatic rings whereas the hydrophilic part contains a functional amine group that can be ionized (43). CADs family comprises a broad spectrum of compound classes, including dozens of approved drugs that are used to treat a wide range of diseases including allergies, heart diseases, and psychiatric disorders (44,45). Since the antitumoral activity of compounds investigated in this study is not apparently related to their conventional pharmacological properties and clinical use, we investigated the CADs properties of psychotropic drugs used in our screening evaluating their chemical structure, logP and pKa in comparison to the wellknown CADs compounds amiodarone, chlorpromazine and chloroquine ( Supplementary Table 2) (46,47).…”

“…CADs can readily pass through phospholipids bilayers, particularly through membranes with a large transmembrane potential such as the mitochondrial inner membrane. They readily accumulate in the mitochondrial matrix, causing mitochondrial membrane depolarization (45,48,49). Therefore, we evaluated the alteration in mitochondrial membrane potential ( ψm) as a function of drug treatment, using the lipophilic cationic dye JC-1 (50).…”

Is Autophagy Involved in the Diverse Effects of Antidepressants?

“…Given the multitude of the cellular effects of antidepressants beyond monoaminergic neurotransmission, and the plethora of at least partially redundant autophagy proteins [9], it will be challenging to pinpoint the exact mechanisms that evoke the autophagic response. Their characteristic as cationic amphiphilic chemicals might play a role [61,64], and new tools to decipher novel molecules directly interacting with antidepressants should also contribute to elucidating their molecular mode of action [64,65].…”

Application of the Tissue Composition–Based Model to Minipig for Predicting the Volume of Distribution at Steady State and Dermis-to-Plasma Partition Coefficients of Drugs Used in the Physiologically Based Pharmacokinetics Model in Dermatology

“…Moreover, it is also reported that for a cationic amphiphilic base, its intracellular distribution pattern also strongly depends on drug concentration and exposure time because the induction of phospholipidosis in tissues increases the production of AP in the biological membranes for a greater membrane accumulation and tissue distribution. 45 In this case, their partitioning into the membranes might become even more important compared to n-octanol. This aspect would also need to be added in the TCM to predict tissue partitioning over time for this specific class of drugs.…”