Lysosomal membrane integrity in fibroblasts derived from patients with Gaucher disease.

Gaucher disease (GD) is a recessively inherited lysosomal storage disorder characterized by a deficiency of lysosomal glucocerebrosidase (GBA1). This deficiency results in the accumulation of its substrate, glucosylceramide (GlcCer), within lysosomes. Here, we investigated lysosomal abnormalities in fibroblasts derived from patients with GD. It is noteworthy that the cellular distribution of lysosomes and lysosomal proteolytic activity remained largely unaffected in GD fibroblasts. However, we found that lysosomal membranes of GD fibroblasts were susceptible to damage when exposed to a lysosomotropic agent. Moreover, the susceptibility of lysosomal membranes to a lysosomotropic agent could be partly restored by exogenous expression of wild-type GBA1. Here, we report that the lysosomal membrane integrity is altered in GD fibroblasts, but lysosomal distribution and proteolytic activity is not significantly altered.Key words: glucosylceramide, lysosome, Gaucher disease, lysosomotropic agent.

Anticancer activity features of imidazole-based ionic liquids and lysosomotropic detergents: in silico and in vitro studies.

Long-chain imidazole-based ionic liquids (compounds 2, 4, 9) and lysosomotropic detergents (compounds 7, 3, 8) with potent anticancer activity were synthesized. Their inhibitory activities against neuroblastoma and leukaemia cell lines were predicted by the new in silico QSAR models. The cytotoxic activities of the synthesized imidazole derivatives were investigated on the SK-N-DZ (human neuroblastoma) and K-562 (human chronic myeloid leukaemia) cell lines. Compounds 2 and 7 showed the highest in vitro cytotoxic effect on both cancer cell lines. The docking procedure of compounds 2 and 7 into the NAD+ coenzyme binding site of deacetylase Sirtuin-1 (SIRT-1) showed the formation of protein-ligand complexes with calculated binding energies of - 8.0 and - 8.1 kcal/mol, respectively. The interaction of SIRT1 with compounds 2, 7 and 9 and the interaction of Bromodomain-containing protein 4 (BRD4) with compounds 7 and 9 were also demonstrated by thermal shift assay. Compounds 2, 4, 7 and 9 inhibited SIRT1 deacetylase activity in the SIRT-Glo assay. Compounds 7 and 9 showed a moderate inhibitory activity against Aurora kinase A. In addition, compounds 3, 4, 8 and 9 inhibited the Janus kinase 2 activity. The results obtained showed that long-chain imidazole derivatives exhibited cytotoxic activities on K562 leukaemia and SK-N-DZ neuroblastoma cell lines. Furthermore, these compounds inhibited a panel of molecular targets involved in leukaemia and neuroblastoma tumorigenesis. All these results suggest that both long-chain imidazole-based ionic liquids and lysosomotropic detergents may be an effective alternative for the treatment of neuroblastoma and chronic myeloid leukemia and merit further investigation.

Design, synthesis and antiviral evaluation of novel conjugates of the 1,7,7-trimethylbicyclo[2.2.1]heptane scaffold and saturated N-heterocycles via 1,2,3-triazole linker.

A new series of heterocyclic derivatives with a 1,7,7-trimethylbicyclo[2.2.1]heptane fragment was designed, synthesised and biologically evaluated. Synthesis of the target compounds was performed using the Cu(I) catalysed cycloaddition reaction. The key starting substances in the click reaction were an alkyne containing a 1,7,7-trimethylbicyclo[2.2.1]heptane fragment and a series of azides with saturated nitrogen-containing heterocycles. Some of the derivatives were found to exhibit strong antiviral activity against Marburg and Ebola pseudotype viruses. Lysosomal trapping assays revealed the derivatives to possess lysosomotropic properties. The molecular modelling study demonstrated the binding affinity between the compounds investigated and the possible active site to be mainly due to hydrophobic interactions. Thus, combining a natural hydrophobic structural fragment and a lysosome-targetable heterocycle may be an effective strategy for designing antiviral agents.

Preclinical pharmacokinetic and in vitro metabolic stability study of lysosomotropic autophagy inhibitor, IITZ-01 in mice by using UPLC-MS/MS.

The present study evaluates the pharmacokinetics and metabolic stability of a novel lysosomotropic autophagy inhibitor, IITZ-01 using an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS-MS). It is required as this lead molecule awaits pre-clinical studies for development because of significant therapeutic outcomes in triple-negative breast cancer and renal cancer. A bioanalytical method for the quantitative determination of IITZ-01 in the plasma of mice was developed using the UPLC-MS/MS technique. The UPLC-MS/MS method was validated according to US-FDA bioanalytical guidance and successfully applied to study the pharmacokinetics and metabolic stability. Separation of IITZ- 01 and ZSTK474 (IS) from endogenous components with high selectivity and sensitivity (0.5 ng/mL) was achieved using Waters Acquity BEH C-18 column (50 mm × 2.1 mm, 1.7 µm). A gradient mobile phase consisting of 0.1 % formic acid in water and 0.1 % formic acid in acetonitrile was applied at a flow rate of 0.2 mL/min. Electrospray ionization was employed in positive ion mode for detection, while quantification utilized the multiple reaction monitoring (MRM) mode. This involved using [M+H]+fragment ions at m/z 483.19 â†’ 235.09 for IITZ-01 and m/z 418 â†’ 138 for the internal standard (IS). The method was validated over the calibration range of 0.5-800 ng/mL. The LLOQ of IITZ-01 was 0.5 ng/mL in mice plasma. The method demonstrated good in terms of intra- and inter-day precision and accuracy. The matrix effect was found to be negligible, and the stability data were within acceptable limits. The validated technique supports suitability, reliability, reproducibility, and sensitivity for the pre-clinical investigation of IITZ-01 pharmacokinetics in mice and metabolic stability in human liver microsomes.

Casein kinase I inhibitor D4476 influences autophagy and apoptosis in chloroquine-induced adult retinal pigment epithelial-19 cells.

The antimalarial drug chloroquine (CQ) induces retinopathy, a disorder characterized by lysosomotropic alteration. In this study, we examined whether D4476 (4-(4-(2,3-dihydrobenzo [1,4] dioxin-6-yl)-5-pyridin-2-yl-1H-imidazole-2-yl) benzamide), a specific casein kinase 1 inhibitor, alleviate CQ-induced retinopathy in adult retinal pigment epithelial (ARPE-19) cells. Cultured ARPE-19 cells were exposed to CQ with or without D4476 and cell death was quantified using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. To examine autophagy flux, ARPE-19 cells were transfected with green fluorescence protein light chain 3 (GFP-LC3)-red fluorescence protein (RFP)-LC3ΔG plasmid DNA and co-stained with the lysosomal-associated membrane protein (LAMP)-1 antibody. Western blotting and fluorescence-activated cell sorting (FACS) showed apoptosis, whereas the fluorescence intensity of 2'-7'-dichlorofluorescein diacetate revealed levels of cellular oxidative stress. We then confirmed the effect of D4476 on the interaction between Beclin 1 and B-cell lymphoma-2 (Bcl-2) through immunoprecipitation with an anti-Bcl-2 antibody. Following CQ exposure, ARPE-19 cells accumulated autophagosomes because of defective lysosomal degradation. Furthermore, CQ trapped Beclin 1 with Bcl-2, disturbing autophagy initiation and autolysosome formation. However, D4476 alleviated CQ-induced effects by rescuing ARPE-19 cells from CQ-induced toxicity by modulating the association between Beclin 1 and Bcl-2. Therefore, D4476 controls autophagy and apoptosis simultaneously by upregulating autophagy flux, decreasing ROS formation, and triggering the expression of anti-apoptotic proteins through inhibition of mTOR, JNK, and p38 MAPK signals. We conclude that D4476 is a promising treatment strategy for CQ-mediated retinopathy.

Potential Role of the Antidepressants Fluoxetine and Fluvoxamine in the Treatment of COVID-19.

Mapping non-canonical cellular pathways affected by approved medications can accelerate drug repurposing efforts, which are crucial in situations with a global impact such as the COVID-19 pandemic. Fluoxetine and fluvoxamine are well-established and widely-used antidepressive agents that act as serotonin reuptake inhibitors (SSRI-s). Interestingly, these drugs have been reported earlier to act as lysosomotropic agents, inhibitors of acid sphingomyelinase in the lysosomes, and as ligands of sigma-1 receptors, mechanisms that might be used to fight severe outcomes of COVID-19. In certain cases, these drugs were administered for selected COVID-19 patients because of their antidepressive effects, while in other cases, clinical studies were performed to assess the effect of these drugs on treating COVID-19 patients. Clinical studies produced promising data that encourage the further investigation of fluoxetine and fluvoxamine regarding their use in COVID-19. In this review, we summarize experimental data and the results of the performed clinical studies. We also provide an overview of previous knowledge on the tissue distribution of these drugs and by integrating this information with the published experimental results, we highlight the real opportunity of using these drugs in our fight against COVID-19.

Identification of madangamine A as a novel lysosomotropic agent to inhibit autophagy.

Madangamines are marine natural products isolated from Xestospongia ingens, and madangamine A-E with a different D-ring structure have been reported. We have reported that madangamine A has strong anti-proliferative activity against various human cancer cell lines. In this study, to clarify the anti-proliferative activity of madangamine A, we searched for molecular target of the madangamine A in human cells. Treatment with madangamine A increased the levels of LC3-II and p62, autophagy-related proteins, concomitant with growth inhibition. Moreover, madangamine A resulted in lysosome enlargement and increase in lysosomal pH, which are same phenomena observed in chloroquine-treated cells. These results suggest that madangamine A is a novel lysosome inhibitor, and the anti-proliferative activity of madangamine A is due to the inhibition of lysosome function.

Roles of lysosomotropic agents on LRRK2 activation and Rab10 phosphorylation.

Leucine-rich repeat kinase 2 (LRRK2), the major causative gene product of autosomal-dominant Parkinson's disease, is a protein kinase that phosphorylates a subset of Rab GTPases. Since pathogenic LRRK2 mutations increase its ability to phosphorylate Rab GTPases, elucidating the mechanisms of how Rab phosphorylation is regulated by LRRK2 is of great importance. We have previously reported that chloroquine-induced lysosomal stress facilitates LRRK2 phosphorylation of Rab10 to maintain lysosomal homeostasis. Here we reveal that Rab10 phosphorylation by LRRK2 is potently stimulated by treatment of cells with a set of lysosome stressors and clinically used lysosomotropic drugs. These agents commonly promoted the formation of LRRK2-coated enlarged lysosomes and extracellular release of lysosomal enzyme cathepsin B, the latter being dependent on LRRK2 kinase activity. In contrast to the increase in Rab10 phosphorylation, treatment with lysosomotropic drugs did not increase the enzymatic activity of LRRK2, as monitored by its autophosphorylation at Ser1292 residue, but rather enhanced the molecular proximity between LRRK2 and its substrate Rab GTPases on the cytosolic surface of lysosomes. Lysosomotropic drug-induced upregulation of Rab10 phosphorylation was likely a downstream event of Rab29 (Rab7L1)-mediated enzymatic activation of LRRK2. These results suggest a regulated process of Rab10 phosphorylation by LRRK2 that is associated with lysosomal overload stress, and provide insights into the novel strategies to halt the aberrant upregulation of LRRK2 kinase activity.

Interactions of the Lysosomotropic Detergent O-Methyl-Serine Dodecylamide Hydrochloride (MSDH) with Lipid Bilayer Membranes-Implications for Cell Toxicity.

O-methyl-serine dodecylamine hydrochloride (MSDH) is a detergent that accumulates selectively in lysosomes, a so-called lysosomotropic detergent, with unexpected chemical properties. At physiological pH, it spontaneously forms vesicles, which disassemble into small aggregates (probably micelles) below pH 6.4. In this study, we characterize the interaction between MSDH and liposomes at different pH and correlate the findings to toxicity in human fibroblasts. We find that the effect of MSDH on lipid membranes is highly pH-dependent. At neutral pH, the partitioning of MSDH into the liposome membrane is immediate and causes the leakage of small fluorophores, unless the ratio between MSDH and lipids is kept low. At pH 5, the partitioning of MSDH into the membrane is kinetically impeded since MSDH is charged and a high ratio between MSDH and the lipids is required to permeabilize the membrane. When transferred to cell culture conditions, the ratio between MSDH and plasma membrane lipids must therefore be low, at physiological pH, to maintain plasma membrane integrity. Transmission electron microscopy suggests that MSDH vesicles are taken up by endocytosis. As the pH of the endosomal compartment progressively drops, MSDH vesicles disassemble, leading to a high concentration of increasingly charged MSDH in small aggregates inside the lysosomes. At sufficiently high MSDH concentrations, the lysosome is permeabilized, the proteolytic content released to the cytosol and apoptotic cell death is induced.

Drug Sequestration in Lysosomes as One of the Mechanisms of Chemoresistance of Cancer Cells and the Possibilities of Its Inhibition.

Resistance to chemotherapeutics and targeted drugs is one of the main problems in successful cancer therapy. Various mechanisms have been identified to contribute to drug resistance. One of those mechanisms is lysosome-mediated drug resistance. Lysosomes have been shown to trap certain hydrophobic weak base chemotherapeutics, as well as some tyrosine kinase inhibitors, thereby being sequestered away from their intracellular target site. Lysosomal sequestration is in most cases followed by the release of their content from the cell by exocytosis. Lysosomal accumulation of anticancer drugs is caused mainly by ion-trapping, but active transport of certain drugs into lysosomes was also described. Lysosomal low pH, which is necessary for ion-trapping is achieved by the activity of the V-ATPase. This sequestration can be successfully inhibited by lysosomotropic agents and V-ATPase inhibitors in experimental conditions. Clinical trials have been performed only with lysosomotropic drug chloroquine and their results were less successful. The aim of this review is to give an overview of lysosomal sequestration and expression of acidifying enzymes as yet not well known mechanism of cancer cell chemoresistance and about possibilities how to overcome this form of resistance.

COVID-19/SARS-CoV-2 Infection: Lysosomes and Lysosomotropism Implicate New Treatment Strategies and Personal Risks.

In line with SARS and MERS, the SARS-CoV-2/COVID-19 pandemic is one of the largest challenges in medicine and health care worldwide. SARS-CoV-2 infection/COVID-19 provides numerous therapeutic targets, each of them promising, but not leading to the success of therapy to date. Neither an antiviral nor an immunomodulatory therapy in patients with SARS-CoV-2 infection/COVID-19 or pre-exposure prophylaxis against SARS-CoV-2 has proved to be effective. In this review, we try to close the gap and point out the likely relationships among lysosomotropism, increasing lysosomal pH, SARS-CoV-2 infection, and disease process, and we deduce an approach for the treatment and prophylaxis of COVID-19, and cytokine release syndrome (CRS)/cytokine storm triggered by bacteria or viruses. Lysosomotropic compounds affect prominent inflammatory messengers (e.g., IL-1B, CCL4, CCL20, and IL-6), cathepsin-L-dependent viral entry of host cells, and products of lysosomal enzymes that promote endothelial stress response in systemic inflammation. As supported by recent clinical data, patients who have already taken lysosomotropic drugs for other pre-existing conditions likely benefit from this treatment in the COVID-19 pandemic. The early administration of a combination of antivirals such as remdesivir and lysosomotropic drugs, such as the antibiotics teicoplanin or dalbavancin, seems to be able to prevent SARS-CoV-2 infection and transition to COVID-19.

Lysosomotropic Features and Autophagy Modulators among Medical Drugs: Evaluation of Their Role in Pathologies.

The concept of lysosomotropic agents significantly changed numerous aspects of cellular biochemistry, biochemical pharmacology, and clinical medicine. In the present review, we focused on numerous low-molecular and high-molecular lipophilic basic compounds and on the role of lipophagy and autophagy in experimental and clinical medicine. Attention was primarily focused on the most promising agents acting as autophagy inducers, which offer a new window for treatment and/or prophylaxis of various diseases, including type 2 diabetes mellitus, Parkinson's disease, and atherosclerosis. The present review summarizes current knowledge on the lysosomotropic features of medical drugs, as well as autophagy inducers, and their role in pathological processes.

Derailed Ceramide Metabolism in Atopic Dermatitis (AD): A Causal Starting Point for a Personalized (Basic) Therapy.

Active rebuilding, stabilizing, and maintaining the lipid barrier of the skin is an encouraging disease management and care concept for dry skin, atopic dermatitis (eczema, neurodermatitis), and psoriasis. For decades, corticosteroids have been the mainstay of topical therapy for atopic dermatitis; however, innovations within the scope of basic therapy are rare. In (extremely) dry, irritated, or inflammatory skin, as well as in lesions, an altered (sphingo)lipid profile is present. Recovery of a balanced (sphingo)lipid profile is a promising target for topical and personalized treatment and prophylaxis. New approaches for adults and small children are still lacking. With an ingenious combination of commonly used active ingredients, it is possible to restore and reinforce the dermal lipid barrier and maintain refractivity. Lysosomes and ceramide de novo synthesis play a key role in attenuation of the dermal lipid barrier. Linoleic acid in combination with amitriptyline in topical medication offers the possibility to relieve patients affected by dry and itchy skin, mild to moderate atopic dermatitis lesions, and eczemas without the commonly occurring serious adverse effects of topical corticosteroids or systemic antibody administration.

Typical and Atypical Inducers of Lysosomal Cell Death: A Promising Anticancer Strategy.

Lysosomes are conservative organelles with an indispensable role in cellular degradation and the recycling of macromolecules. However, in light of recent findings, it has emerged that the role of lysosomes in cancer cells extends far beyond cellular catabolism and includes a variety of cellular pathways, such as proliferation, metastatic potential, and drug resistance. It has been well described that malignant transformation leads to alterations in lysosomal structure and function, which, paradoxically, renders cancer cells more sensitive to lysosomal destabilization. Furthermore, lysosomes are implicated in the regulation and execution of cell death in response to diverse stimuli and it has been shown that lysosome-dependent cell death can be utilized to overcome apoptosis and drug resistance. Thus, the purpose of this review is to characterize the role of lysosome in cancer therapy and to describe how these organelles impact treatment resistance. We summarized the characteristics of typical inducers of lysosomal cell death, which exert its function primarily via alterations in the lysosomal compartment. The review also presents other anticancer agents with the predominant mechanism of action different from lysosomal destabilization, the activity of which is influenced by lysosomal signaling, including classical chemotherapeutics, kinase inhibitors, monoclonal antibodies, as well as photodynamic therapy.

Effect of lysosomotropic molecules on cellular homeostasis.

Weak bases that readily penetrate through the lipid bilayer and accumulate inside the acidic organelles are known as lysosomotropic molecules. Many lysosomotropic compounds exhibit therapeutic activity and are commonly used as antidepressant, antipsychotic, antihistamine, or antimalarial agents. Interestingly, studies also have shown increased sensitivity of cancer cells to certain lysosomotropic agents and suggested their mechanism of action as a promising approach for selective destruction of cancer cells. However, their chemotherapeutic utility may be limited due to various side effects. Hence, understanding the homeostatic alterations mediated by lysosomotropic compounds has significant importance for revealing their true therapeutic potential as well as toxicity. In this review, after briefly introducing the concept of lysosomotropism and classifying the lysosomotropic compounds into two major groups according to their cytotoxicity on cancer cells, we focused on the subcellular alterations mediated by class-II lysosomotropic compounds. Briefly, their effect on intracellular cholesterol homeostasis, autophagy and lysosomal sphingolipid metabolism was discussed. Accordingly, class-II lysosomotropic molecules inhibit intracellular cholesterol transport, leading to the accumulation of cholesterol inside the late endosomal-lysosomal cell compartments. However, the accumulated lysosomal cholesterol is invisible to the cellular homeostatic circuits, hence class-II lysosomotropic molecules also upregulate cholesterol synthesis pathway as a downstream event. Considering the fact that Niemann-Pick disease, a lysosomal cholesterol storage disorder, also triggers similar pathologic abnormalities, this review combines the knowledge obtained from the Niemann-Pick studies and lysosomotropic compounds. Taken together, this review is aimed at allowing readers a better understanding of subcellular alterations mediated by lysosomotropic drugs, as well as their potential therapeutic and/or toxic activities.

Autophagy inhibitors.

Autophagy is a lysosome-dependent mechanism of intracellular degradation. The cellular and molecular mechanisms underlying this process are highly complex and involve multiple proteins, including the kinases ULK1 and Vps34. The main function of autophagy is the maintenance of cell survival when modifications occur in the cellular environment. During the past decade, extensive studies have greatly improved our knowledge and autophagy has exploded as a research field. This process is now widely implicated in pathophysiological processes such as cancer, metabolic, and neurodegenerative disorders, making it an attractive target for drug discovery. In this review, we will summarize the different types of inhibitors that affect the autophagy machinery and provide some potential therapeutic perspectives.

Lysosomotropic cationic drugs induce cytostatic and cytotoxic effects: Role of liposolubility and autophagic flux and antagonism by cholesterol ablation.

Cation trapping in acidic cell compartments determines an antiproliferative effect that has a potential interest in oncology, as shown by clinical data and trials involving chloroquine and hydroxychloroquine. To further characterize the mechanism of this effect, we studied a series of 6 substituted triethylamine (s-Et3N) drugs that encompasses a wide range of liposolubility (amiodarone, quinacrine, chloroquine, hydroxychloroquine, lidocaine, and procainamide). Three tumor cell lines and primary human endothelial cells were exploited in proliferation assays (48h, cell counts). Accumulation of the autophagic effector LC3 II and the apoptotic marker cleaved PARP1 (immunoblots), cytotoxicity, cell cycle analysis and endocytic function were further tested in the p53-null histiocytic lymphoma U937 line. A profound and desynchronized antiproliferative effect was observed in response to all s-Et3Ns with essentially no cell type specificity. Predictors of s-Et3N potency were liposolubility and the acute accumulation of the autophagic effector LC3 II (6h-treatments). For each s-Et3N, there was an antiproliferative concentration range where cytotoxicity and apoptosis were not triggered in U937 cells (24-48h-treatments). Quinacrine was the most potent cytostatic drug (1-5µM). Co-treatment of cells with inhibitors of cholesterol, ß-cyclodextrin or lovastatin, partially reversed the antiproliferative effect of each s-Et3N. The cytopathology induced by cationic drug accumulation includes a cytostatic effect. Its intensity is cell type- and p53-independent, but predicted by the inhibition of autophagic flux and by the liposolubility of individual drugs and alleviated by cholesterol ablation. The superiority of quinacrine, biomarker value of LC3 II and antagonism by a statin may be clinically relevant.

Downregulation of Organic Anion Transporting Polypeptide (OATP) 1B1 Transport Function by Lysosomotropic Drug Chloroquine: Implication in OATP-Mediated Drug-Drug Interactions.

Organic anion transporting polypeptide (OATP) 1B1 mediates the hepatic uptake of many drugs including lipid-lowering statins. Decreased OATP1B1 transport activity is often associated with increased systemic exposure of statins and statin-induced myopathy. Antimalarial drug chloroquine (CQ) is also used for long-term treatment of rheumatoid arthritis and systemic lupus erythematosus. CQ is lysosomotropic and inhibits protein degradation in lysosomes. The current studies were designed to determine the effects of CQ on OATP1B1 protein degradation, OATP1B1-mediated transport in OATP1B1-overexpressing cell line, and statin uptake in human sandwich-cultured hepatocytes (SCH). Treatment with lysosome inhibitor CQ increased OATP1B1 total protein levels in HEK293-OATP1B1 cells and in human SCH as determined by OATP1B1 immunoblot. In HEK293-FLAG-tagged OATP1B1 stable cell line, co-immunofluorescence staining indicated that intracellular FLAG-OATP1B1 is colocalized with lysosomal associated membrane glycoprotein (LAMP)-2, a marker protein of late endosome/lysosome. Enlarged LAMP-2-positive vacuoles with FLAG-OATP1B1 protein retained inside were readily detected in CQ-treated cells, consistent with blocking lysosomal degradation of OATP1B1 by CQ. In HEK293-OATP1B1 cells, without pre-incubation, CQ concentrations up to 100 µM did not affect OATP1B1-mediated [(3)H]E217G accumulation. However, pre-incubation with CQ at clinically relevant concentration(s) significantly decreased [(3)H]E217G and [(3)H]pitavastatin accumulation in HEK293-OATP1B1 cells and [(3)H]pitavastatin accumulation in human SCH. CQ pretreatment (25 µM, 2 h) resulted in ∼1.9-fold decrease in Vmax without affecting Km of OATP1B1-mediated [(3)H]E217G transport in HEK293-OATP1B1 cells. Pretreatment with monensin and bafilomycin A1, which also have lysosome inhibition activity, significantly decreased OATP1B1-mediated transport in HEK293-OATP1B1 cells. Pharmacoepidemiologic studies using data from the U.S. Food and Drug Administration Adverse Event Reporting System indicated that CQ plus pitavastatin, rosuvastatin, and pravastatin, which are minimally metabolized by the cytochrome P450 enzymes, led to higher myopathy risk than these statins alone. In summary, the present studies report novel findings that lysosome is involved in degradation of OATP1B1 protein and that pre-incubation with lysosomotropic drug CQ downregulates OATP1B1 transport activity. Our in vitro data in combination with pharmacoepidemiologic studies support that CQ has potential to cause OATP-mediated drug-drug interactions.

PUMA-dependent apoptosis in NSCLC cancer cells by a dimeric ß-carboline.

Dimeric ß-carbolines are cytotoxic against multiple NSCLC cell lines, and we report herein our preliminary studies on the mechanism of action of these dimeric structures. Dimeric ß-carboline 1, which is more potent than the corresponding monomer in NSCLC cell lines, is a lysosomotropic agent that inhibits autophagy and mediates cell death by apoptosis, upregulating the pro-apoptotic BH3-only protein PUMA (p53 upregulated modulator of apoptosis) in a dose dependent manner.

Chloroquine analogues in drug discovery: new directions of uses, mechanisms of actions and toxic manifestations from malaria to multifarious diseases.

Antimalarial drugs (e.g. chloroquine and its close structural analogues) were developed primarily to treat malaria; however, they are beneficial for many dermatological, immunological, rheumatological and severe infectious diseases, for which they are used mostly today. Chloroquine and hydroxychloroquine, two of the most fascinating drugs developed in the last 50 years, are increasingly recognized for their effectiveness in myriad non-malarial diseases. In advanced research, chloroquine and hydroxychloroquine have been shown to have various immunomodulatory and immunosuppressive effects, and currently have established roles in the management of rheumatic diseases, lupus erythematosus (different forms) and skin diseases, and in the treatment of different forms of cancer. Recently, chloroquine analogues have also been found to have metabolic, cardiovascular, antithrombotic and antineoplastic effects. This review is concerned with the lysosomotropic, anti-inflammatory and immunomodulatory mechanisms of chloroquine, hydroxychloroquine, quinacrine and related analogues, and the current evidence for both their beneficial effects and potential adverse manifestations in various diseases.