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Marine Drugs Sep 2022N-methylpretrichodermamide B (NB) is a biologically active epidithiodiketopiperazine isolated from several strains of the algae-derived fungus sp. Recently, we reported...
N-methylpretrichodermamide B (NB) is a biologically active epidithiodiketopiperazine isolated from several strains of the algae-derived fungus sp. Recently, we reported the first data on its activity in human cancer cells lines in vitro. Here, we investigated the activity, selectivity, and mechanism of action of NB in human prostate cancer cell lines, including drug-resistant subtypes. NB did not reveal cross-resistance to docetaxel in the PC3-DR cell line model and was highly active in hormone-independent 22Rv1 cells. NB-induced cell death was stipulated by externalization of phosphatidylserine and activation of caspase-3. Moreover, inhibition of caspase activity by z-VAD(OMe)-fmk did not affect NB cytotoxicity, suggesting a caspase-independent cell death induced by NB. The compound has a moderate p-glycoprotein (p-gp) substrate-like affinity and can simultaneously inhibit p-gp at nanomolar concentrations. Therefore, NB resensitized p-gp-overexpressing PC3-DR cells to docetaxel. A kinome profiling of the NB-treated cells revealed, among other things, an induction of mitogen-activated protein kinases JNK1/2 and p38. Further functional analysis confirmed an activation of both kinases and indicated a prosurvival role of this biological event in the cellular response to the treatment. Overall, NB holds promising anticancer potential and further structure-activity relationship studies and structural optimization are needed in order to improve its biological properties.
Topics: Humans; Male; Antineoplastic Agents; Apoptosis; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Caspase 3; Cell Line, Tumor; Docetaxel; Drug Resistance, Neoplasm; Hormones; Phosphatidylserines; Prostatic Neoplasms
PubMed: 36286421
DOI: 10.3390/md20100597 -
Journal of Molecular Cell Biology Apr 2019Since wild-type p53 is central for maintaining genomic stability and preventing oncogenesis, its coding gene TP53 is highly mutated in ~50% of human cancers, and its... (Review)
Review
Since wild-type p53 is central for maintaining genomic stability and preventing oncogenesis, its coding gene TP53 is highly mutated in ~50% of human cancers, and its activity is almost abrogated in the rest of cancers. Approximately 80% of p53 mutations are single point mutations with several hotspot mutations. Besides loss of function and dominant-negative effect on the wild-type p53 activity, the hotspot p53 mutants also acquire new oncogenic functions, so-called 'gain-of-functions' (GOF). Because the GOF of mutant p53 is highly associated with late-stage malignance and drug resistance, these p53 mutants have become hot targets for developing novel cancer therapies. In this essay, we review some recent progresses in better understanding of the role of mutant p53 GOF in chemoresistance and the underlying mechanisms, and discuss the pros and cons of targeting mutant p53 for the development of anti-cancer therapies.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Antineoplastic Agents, Alkylating; Apoptosis; Drug Resistance, Neoplasm; Gain of Function Mutation; Genomic Instability; Humans; Neoplasm Metastasis; Neoplasms; Tumor Suppressor Protein p53
PubMed: 30508182
DOI: 10.1093/jmcb/mjy072 -
PloS One 2021P-glycoprotein (P-gp) is a critical membrane transporter in the blood brain barrier (BBB) and is implicated in Alzheimer's disease (AD). However, previous studies on the...
P-glycoprotein (P-gp) is a critical membrane transporter in the blood brain barrier (BBB) and is implicated in Alzheimer's disease (AD). However, previous studies on the ability of P-gp to directly transport the Alzheimer's associated amyloid-β (Aβ) protein have produced contradictory results. Here we use molecular dynamics (MD) simulations, transport substrate accumulation studies in cell culture, and biochemical activity assays to show that P-gp actively transports Aβ. We observed transport of Aβ40 and Aβ42 monomers by P-gp in explicit MD simulations of a putative catalytic cycle. In in vitro assays with P-gp overexpressing cells, we observed enhanced accumulation of fluorescently labeled Aβ42 in the presence of Tariquidar, a potent P-gp inhibitor. We also showed that Aβ42 stimulated the ATP hydrolysis activity of isolated P-gp in nanodiscs. Our findings expand the substrate profile of P-gp, and suggest that P-gp may contribute to the onset and progression of AD.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Adenosine Triphosphate; Alzheimer Disease; Amyloid beta-Peptides; Biocatalysis; Blood-Brain Barrier; Cell Line, Tumor; Disease Progression; Humans; Hydrolysis; Ligands; Molecular Docking Simulation; Molecular Dynamics Simulation; Peptide Fragments; Protein Binding; Protein Conformation, beta-Strand; Protein Domains; Protein Transport; Quinolines; Signal Transduction; Substrate Specificity
PubMed: 33901197
DOI: 10.1371/journal.pone.0250371 -
Antimicrobial Agents and Chemotherapy Feb 2015
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Amphotericin B; Animals; Antifungal Agents; Blood-Brain Barrier; Cryptococcosis; Male; Verapamil
PubMed: 25628395
DOI: 10.1128/AAC.04768-14 -
Molecules (Basel, Switzerland) Nov 2023P-glycoprotein (P-gp) is a crucial membrane transporter situated on the cell's apical surface, being responsible for eliminating xenobiotics and endobiotics. P-gp... (Review)
Review
P-glycoprotein (P-gp) is a crucial membrane transporter situated on the cell's apical surface, being responsible for eliminating xenobiotics and endobiotics. P-gp modulators are compounds that can directly or indirectly affect this protein, leading to changes in its expression and function. These modulators can act as inhibitors, inducers, or activators, potentially causing drug-drug interactions (DDIs). This comprehensive review explores diverse models and techniques used to assess drug-induced P-gp modulation. We cover several approaches, including , , , and methods, with their respective strengths and limitations. Additionally, we explore the therapeutic implications of DDIs involving P-gp, with a special focus on the renal and intestinal elimination of P-gp substrates. This involves enhancing the removal of toxic substances from proximal tubular epithelial cells into the urine or increasing the transport of compounds from enterocytes into the intestinal lumen, thereby facilitating their excretion in the feces. A better understanding of these interactions, and of the distinct techniques applied for their study, will be of utmost importance for optimizing drug therapy, consequently minimizing drug-induced adverse and toxic effects.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Membrane Transport Proteins; ATP Binding Cassette Transporter, Subfamily B; Kidney; Drug Interactions
PubMed: 38005253
DOI: 10.3390/molecules28227532 -
Journal of Natural Products Mar 2022Photoaffinity labeling approaches have historically been used in pharmacology to identify molecular targets. This methodology has played a pivotal role in identifying... (Review)
Review
Photoaffinity labeling approaches have historically been used in pharmacology to identify molecular targets. This methodology has played a pivotal role in identifying drug-binding domains and searching for novel compounds that may interact at these domains. In this review we focus on studies of microtubule stabilizing agents of natural product origin, specifically taxol (paclitaxel). Taxol and other microtubule interacting agents bind to both P-glycoprotein (ABCB1), a drug efflux pump that reduces intracellular drug accumulation, and the tubulin/microtubule system. Both binding relationships modulate drug efficacy and are of immense interest to basic and translational scientists, primarily because of their association with drug resistance for this class of molecules. We present this body of work and acknowledge its value as fundamental to understanding the mechanisms of taxol and elucidation of the taxol pharmacophore. Furthermore, we highlight the ability to multiplex photoaffinity approaches with other technologies to further enhance our understanding of pharmacologic interactions at an atomic level. Thus, photoaffinity approaches offer a relatively inexpensive and robust technique that will continue to play an important role in drug discovery for the foreseeable future.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Excipients; Microtubules; Paclitaxel; Tubulin
PubMed: 35240035
DOI: 10.1021/acs.jnatprod.2c00106 -
PloS One 2018This paper describes the preparation of giant unilamellar vesicles with reconstituted hamster P-glycoprotein (Pgp, ABCB1) for studying the transport activity of this...
This paper describes the preparation of giant unilamellar vesicles with reconstituted hamster P-glycoprotein (Pgp, ABCB1) for studying the transport activity of this efflux pump in individual liposomes using optical microscopy. Pgp, a member of ABC (ATP-binding cassette) transporter family, is known to contribute to the cellular multidrug resistance (MDR) against variety of drugs. The efficacy of many therapeutics is, thus, hampered by this efflux pump, leading to a high demand for simple and effective strategies to monitor the interactions of candidate drugs with this protein. Here, we applied small Pgp proteoliposomes to prepare giant Pgp-bearing liposomes via modified electroformation techniques. The presence of Pgp in the membrane of giant proteoliposomes was confirmed using immunohistochemistry. Assessment of Pgp ATPase activity suggested that this transporter retained its activity upon reconstitution into giant liposomes, with an ATPase specific activity of 439 ± 103 nmol/mg protein/min. For further confirmation, we assessed the transport activity of Pgp in these proteoliposomes by monitoring the translocation of rhodamine 123 (Rho123) across the membrane using confocal microscopy at various ATP concentrations (0-2 mM) and in the presence of Pgp inhibitors. Rate of change in Rho123 concentration inside the liposomal lumen was used to estimate the Rho123 transport rates (1/s) for various ATP concentrations, which were then applied to retrieve the Michaelis-Menten constant (Km) of ATP in Rho123 transport (0.42 ± 0.75 mM). Similarly, inhibitory effects of verapamil, colchicine, and cyclosporin A on Pgp were studied in this system and the IC50 values for these Pgp inhibitors were found 26.6 ± 6.1 μM, 94.6 ± 47.6 μM, and 0.21 ± 0.07 μM, respectively. We further analyzed the transport data using a kinetic model that enabled dissecting the passive diffusion of Rho123 from its Pgp-mediated transport across the membrane. Based on this model, the permeability coefficient of Rho123 across the liposomal membrane was approximately 1.25×10-7 cm/s. Comparing the membrane permeability in liposomes with and without Pgp revealed that the presence of this protein did not have a significant impact on membrane integrity and permeability. Furthermore, we used this model to obtain transport rate constants for the Pgp-mediated transport of Rho123 (m3/mol/s) at various ATP and inhibitor concentrations, which were then applied to estimate values of 0.53 ± 0.66 mM for Km of ATP and 25.2 ± 5.0 μM for verapamil IC50, 61.8 ± 34.8 μM for colchicine IC50, and 0.23 ± 0.09 μM for cyclosporin A IC50. The kinetic parameters obtained from the two analyses were comparable, suggesting a minimal contribution from the passive Rho123 diffusion across the membrane. This approach may, therefore, be applied for screening the transport activity of Pgp against potential drug candidates.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Adenosine Triphosphatases; Adenosine Triphosphate; Animals; Biological Transport; Cricetinae; Drug Resistance, Multiple; Proteolipids; Rhodamine 123
PubMed: 29912971
DOI: 10.1371/journal.pone.0199279 -
Cells Mar 2021Zebrafish has emerged as a powerful model in studies dealing with pigment development and pathobiology of pigment diseases. Due to its conserved pigment pattern with...
Zebrafish has emerged as a powerful model in studies dealing with pigment development and pathobiology of pigment diseases. Due to its conserved pigment pattern with established genetic background, the zebrafish is used for screening of active compounds influencing melanophore, iridophore, and xanthophore development and differentiation. In our study, zebrafish embryos and larvae were used to investigate the influence of third-generation noncompetitive P-glycoprotein inhibitor, tariquidar (TQR), on pigmentation, including phenotype effects and changes in gene expression of chosen chromatophore differentiation markers. Five-day exposure to increasing TQR concentrations (1 µM, 10 µM, and 50 µM) resulted in a dose-dependent augmentation of the area covered with melanophores but a reduction in the area covered by iridophores. The observations were performed in three distinct regions-the eye, dorsal head, and tail. Moreover, TQR enhanced melanophore renewal after depigmentation caused by 0.2 mM 1-phenyl-2-thiourea (PTU) treatment. qPCR analysis performed in 56-h post-fertilization (hpf) embryos demonstrated differential expression patterns of genes related to pigment development and differentiation. The most substantial findings include those indicating that TQR had no significant influence on leukocyte tyrosine kinase, GTP cyclohydrolase 2, tyrosinase-related protein 1, and forkhead box D3, however, markedly upregulated tyrosinase, dopachrome tautomerase and melanocyte inducing transcription factor, and downregulated purine nucleoside phosphorylase 4a. The present study suggests that TQR is an agent with multidirectional properties toward pigment cell formation and distribution in the zebrafish larvae and therefore points to the involvement of P-glycoprotein in this process.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Animals; Cell Differentiation; Gene Expression Profiling; Gene Expression Regulation; Gene Expression Regulation, Developmental; Larva; Melanins; Melanophores; Pigmentation; Quinolines; RNA, Messenger; Zebrafish; Zebrafish Proteins
PubMed: 33804686
DOI: 10.3390/cells10030690 -
Molecules (Basel, Switzerland) Jul 2020Multidrug resistance (MDR) in cancer is one of the main limitations for chemotherapy success. Numerous mechanisms are behind the MDR phenomenon wherein the... (Review)
Review
Multidrug resistance (MDR) in cancer is one of the main limitations for chemotherapy success. Numerous mechanisms are behind the MDR phenomenon wherein the overexpression of the ATP-binding cassette (ABC) transporter proteins P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and multidrug resistance protein 1 (MRP1) is highlighted as a prime factor. Natural product-derived compounds are being addressed as promising ABC transporter modulators to tackle MDR. Flavonoids and terpenoids have been extensively explored in this field as mono or dual modulators of these efflux pumps. Nitrogen-bearing moieties on these scaffolds were proved to influence the modulation of ABC transporters efflux function. This review highlights the potential of semisynthetic nitrogen-containing flavonoid and terpenoid derivatives as candidates for the design of effective MDR reversers. A brief introduction concerning the major role of efflux pumps in multidrug resistance, the potential of natural product-derived compounds in MDR reversal, namely natural flavonoid and terpenoids, and the effect of the introduction of nitrogen-containing groups are provided. The main modifications that have been performed during last few years to generate flavonoid and terpenoid derivatives, bearing nitrogen moieties, such as aliphatic, aromatic and heterocycle amine, amide, and related functional groups, as well as their P-gp, MRP1 and BCRP inhibitory activities are reviewed and discussed.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Drug Resistance, Multiple; Flavonoids; Gene Expression Regulation, Neoplastic; Humans; Multidrug Resistance-Associated Proteins; Neoplasm Proteins; Neoplasms; Nitrogen; Terpenes
PubMed: 32722234
DOI: 10.3390/molecules25153364 -
Cells Apr 2020Doxorubicin is a strong inducer of immunogenic cell death (ICD), but it is ineffective in P-glycoprotein (Pgp)-expressing cells. Indeed, Pgp effluxes doxorubicin and...
Doxorubicin is a strong inducer of immunogenic cell death (ICD), but it is ineffective in P-glycoprotein (Pgp)-expressing cells. Indeed, Pgp effluxes doxorubicin and impairs the immunesensitizing functions of calreticulin (CRT), an "eat-me" signal mediating ICD. It is unknown if classical Pgp inhibitors, designed to reverse chemoresistance, may restore ICD. We addressed this question by using Pgp-expressing cancer cells, treated with Tariquidar, a clinically approved Pgp inhibitor, and -3 compound, a ,-bis(alkanol)amine aryl ester derivative with the same potency of Tariquidar as Pgp inhibitor. In Pgp-expressing/doxorubicin-resistant cells, Tariquidar and -3 increased doxorubicin accumulation and toxicity, reduced Pgp activity, and increased CRT translocation and ATP and HMGB1 release. Unexpectedly, only -3 promoted phagocytosis by dendritic cells and activation of antitumor CD8T-lymphocytes. Although Tariquidar did not alter the amount of Pgp present on cell surface, -3 promoted Pgp internalization and ubiquitination, disrupting its interaction with CRT. Pgp knock-out restores doxorubicin-induced ICD in MDA-MB-231/DX cells that recapitulated the phenotype of -3-treated cells. Our work demonstrates that plasma membrane-associated Pgp prevents a complete ICD notwithstanding the release of ATP and HMGB1, and the exposure of CRT. Pharmacological compounds reducing Pgp activity and amount may act as promising chemo- and immunesensitizing agents.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Apoptosis; Calreticulin; Cell Line, Tumor; Doxorubicin; Drug Resistance, Neoplasm; Endocytosis; Esters; Humans; Immunogenic Cell Death; Kinetics; Proteolysis; Quinolines; Ubiquitination
PubMed: 32331368
DOI: 10.3390/cells9041033