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Biophysical Journal Jun 2024The ATP-binding cassette (ABC) transporter P-glycoprotein (P-gp) is a multidrug efflux pump that is overexpressed in a variety of cancers and associated with the drug...
The ATP-binding cassette (ABC) transporter P-glycoprotein (P-gp) is a multidrug efflux pump that is overexpressed in a variety of cancers and associated with the drug resistance phenomenon. P-gp structures were previously determined in detergent and in nanodiscs, in which different transmembrane helix conformations were found, "straight" and "kinked", respectively, indicating a possible role of the lipid environment on the P-gp structural ensemble. Here, we investigate the dynamic conformational ensembles and protein-lipid interactions of two human P-gp inward-open conformers, straight and kinked, employing all-atom molecular dynamics simulations in asymmetric multicomponent lipid bilayers that mimic the highly specialized hepatocyte membrane in which P-gp is expressed. The two conformers are found to differ in terms of the accessibility of the substrate cavity. The MD simulations show how cholesterol and different lipid species wedge, snorkel, and partially enter within the cavity of the straight P-gp conformer solved in detergent. However, the access to the cavity of kinked P-gp conformer solved in nanodiscs is restricted. Furthermore, the volume and dynamic fluctuations of the substrate cavity largely differ between the two P-gp structures, and are modulated by the presence (or absence) of cholesterol in the membrane and/or of ATP. From the mechanistic perspective, the findings indicate that the straight conformer likely precedes the kinked conformer in the functional working cycle of P-gp, with the latter conformation representing a post substrate-bound state. The inaccessibility of the main transmembrane cavity in the kinked conformer might be crucial in preventing substrate disengagement and transport withdrawal. Remarkably, in our unbiased MD simulations, one transmembrane helix (TM10) of the straight conformer underwent a spontaneous conformational transition to a kinked conformation, underlining the relevance of both conformations in a native phospholipid environment and revealing structural descriptors defining the transition between two P-gp conformers.
PubMed: 38909280
DOI: 10.1016/j.bpj.2024.06.020 -
BioRxiv : the Preprint Server For... Apr 2024The cannabinoid CB2 receptor (CB2R) is a potential therapeutic target for distinct forms of tissue injury and inflammatory diseases. To thoroughly investigate the role...
The cannabinoid CB2 receptor (CB2R) is a potential therapeutic target for distinct forms of tissue injury and inflammatory diseases. To thoroughly investigate the role of CB2R in pathophysiological conditions and for target validation , optimal pharmacological tool compounds are essential. Despite the sizable progress in the generation of potent and selective CB2R ligands, pharmacokinetic parameters are often neglected for studies. Here, we report the generation and characterization of a tetra-substituted pyrazole CB2R full agonist named RNB-61 with high potency ( 0.13-1.81 nM, depending on species) and a peripherally restricted action due to P-glycoprotein mediated efflux from the brain. H and C labelled RNB-61 showed apparent values < 4 nM towards human CB2R in both cell and tissue experiments. The >6000-fold selectivity over CB1 receptors and negligible off-targets , combined with high oral bioavailability and suitable systemic pharmacokinetic (PK) properties, prompted the assessment of RNB-61 in a mouse ischemia-reperfusion model of acute kidney injury (AKI) and in a rat model of chronic kidney injury/inflammation and fibrosis (CKI) induced by unilateral ureteral obstruction. RNB-61 exerted dose-dependent nephroprotective and/or antifibrotic effects in the AKI/CKI models. Thus, RNB-61 is an optimal CB2R tool compound for preclinical studies with superior biophysical and PK properties over generally used CB2R ligands.
PubMed: 38903103
DOI: 10.1101/2024.04.26.591311 -
BioRxiv : the Preprint Server For... Apr 2024The blood-brain barrier (BBB), formed by specialized brain microvascular endothelial cells (BMECs), regulates brain function in health and disease. modeling of the...
The blood-brain barrier (BBB), formed by specialized brain microvascular endothelial cells (BMECs), regulates brain function in health and disease. modeling of the human BBB is limited by the lack of robust protocols to generate BMECs from human iPSCs (hiPSCs). Here, we report generation of reprogrammed BMECs (rBMECs) through combining hiPSC differentiation into BBB-primed endothelial cells (bpECs) and reprogramming with two BBB transcription factors, FOXF2 and ZIC3. rBMECs express a subset of the BBB gene repertoire including tight junctions and transporters, exhibit higher paracellular barrier properties, lower caveolar-mediated transcytosis, and equivalent p-glycoprotein activity compared to primary HBMECs, and can be activated by oligomeric Aβ42. We then generated an hiPSC-derived 3D neurovascular system that incorporates rBMECs, pericytes, and astrocytes using the MIMETAS platform. This novel 3D system closely resembles the BBB at structural and functional levels and can be used to study pathogenic mechanisms of neurological diseases.
PubMed: 38903080
DOI: 10.1101/2024.04.03.588012 -
Cell Reports. Medicine Jun 2024ATP-binding cassette (ABC) transporters facilitate the movement of diverse molecules across cellular membranes, including those within the CNS. While most extensively... (Review)
Review
ATP-binding cassette (ABC) transporters facilitate the movement of diverse molecules across cellular membranes, including those within the CNS. While most extensively studied in microvascular endothelial cells forming the blood-brain barrier (BBB), other CNS cell types also express these transporters. Importantly, disruptions in the CNS microenvironment during disease can alter transporter expression and function. Through this comprehensive review, we explore the modulation of ABC transporters in various brain pathologies and the context-dependent consequences of these changes. For instance, downregulation of ABCB1 may exacerbate amyloid beta plaque deposition in Alzheimer's disease and facilitate neurotoxic compound entry in Parkinson's disease. Upregulation may worsen neuroinflammation by aiding chemokine-mediated CD8 T cell influx into multiple sclerosis lesions. Overall, ABC transporters at the BBB hinder drug entry, presenting challenges for effective pharmacotherapy. Understanding the context-dependent changes in ABC transporter expression and function is crucial for elucidating the etiology and developing treatments for brain diseases.
Topics: Humans; ATP-Binding Cassette Transporters; Animals; Blood-Brain Barrier; Brain; Brain Diseases; Alzheimer Disease
PubMed: 38897176
DOI: 10.1016/j.xcrm.2024.101609 -
Molecules (Basel, Switzerland) May 2024Pseudoginsenoside DQ (PDQ), an ocotillol-type ginsenoside, is synthesized with protopanaxadiol through oxidative cyclization. PDQ exhibits good anti-arrhythmia activity....
Pseudoginsenoside DQ (PDQ), an ocotillol-type ginsenoside, is synthesized with protopanaxadiol through oxidative cyclization. PDQ exhibits good anti-arrhythmia activity. However, the inhibitory effect of PDQ on the cytochrome 450 (CYP450) enzymes and major drug transporters is still unclear. Inhibition of CYP450 and drug transporters may affect the efficacy of the drugs being used together with PDQ. These potential drug-drug interactions (DDIs) are essential for the clinical usage of drugs. In this study, we investigated the inhibitory effect of PDQ on seven CYP450 enzymes and seven drug transporters with in vitro models. PDQ has a significant inhibitory effect on CYP2C19 and P-glycoprotein (P-gp) with a half-inhibitory concentration (IC) of 0.698 and 0.41 μM, respectively. The inhibition of CYP3A4 and breast cancer-resistant protein (BCRP) is less potent, with IC equal to 2.02-6.79 and 1.08 μM, respectively.
Topics: Humans; Ginsenosides; Drug Interactions; Cytochrome P-450 Enzyme System; Cytochrome P-450 Enzyme Inhibitors; ATP Binding Cassette Transporter, Subfamily G, Member 2; Cytochrome P-450 CYP3A; Cytochrome P-450 CYP2C19; Neoplasm Proteins
PubMed: 38893358
DOI: 10.3390/molecules29112482 -
Cell Communication and Signaling : CCS Jun 2024Multidrug resistance (MDR) limits successful cancer chemotherapy. P-glycoprotein (P-gp), BCRP and MRP1 are the key triggers of MDR. Unfortunately, no MDR modulator was...
BACKGROUND
Multidrug resistance (MDR) limits successful cancer chemotherapy. P-glycoprotein (P-gp), BCRP and MRP1 are the key triggers of MDR. Unfortunately, no MDR modulator was approved by FDA to date. Here, we will investigate the effect of BI-2865, a pan-KRAS inhibitor, on reversing MDR induced by P-gp, BCRP and MRP1 in vitro and in vivo, and its reversal mechanisms will be explored.
METHODS
The cytotoxicity of BI-2865 and its MDR removal effect in vitro were tested by MTT assays, and the corresponding reversal function in vivo was assessed through the P-gp mediated KBv200 xenografts in mice. BI-2865 induced alterations of drug discharge and reservation in cells were estimated by experiments of Flow cytometry with fluorescent doxorubicin, and the chemo-drug accumulation in xenografts' tumor were analyzed through LC-MS. Mechanisms of BI-2865 inhibiting P-gp substrate's efflux were analyzed through the vanadate-sensitive ATPase assay, [I]-IAAP-photolabeling assay and computer molecular docking. The effects of BI-2865 on P-gp expression and KRAS-downstream signaling were detected via Western blotting, Flow cytometry and/or qRT-PCR. Subcellular localization of P-gp was visualized by Immunofluorescence.
RESULTS
We found BI-2865 notably fortified response of P-gp-driven MDR cancer cells to the administration of chemo-drugs including paclitaxel, vincristine and doxorubicin, while such an effect was not observed in their parental sensitive cells and BCRP or MRP1-driven MDR cells. Importantly, the mice vivo combination study has verified that BI-2865 effectively improved the anti-tumor action of paclitaxel without toxic injury. In mechanism, BI-2865 prompted doxorubicin accumulating in carcinoma cells by directly blocking the efflux function of P-gp, which more specifically, was achieved by BI-2865 competitively binding to the drug-binding sites of P-gp. What's more, at the effective MDR reversal concentrations, BI-2865 neither varied the expression and location of P-gp nor reduced its downstream AKT or ERK1/2 signaling activity.
CONCLUSIONS
This study uncovered a new application of BI-2865 as a MDR modulator, which might be used to effectively, safely and specifically improve chemotherapeutic efficacy in the clinical P-gp mediated MDR refractory cancers.
Topics: Humans; Animals; Drug Resistance, Neoplasm; Drug Resistance, Multiple; Mice; Cell Line, Tumor; ATP Binding Cassette Transporter, Subfamily B, Member 1; Xenograft Model Antitumor Assays; Mice, Nude; Doxorubicin; Mice, Inbred BALB C; Female
PubMed: 38872211
DOI: 10.1186/s12964-024-01698-4 -
Biomedicine & Pharmacotherapy =... Jul 2024The association between polymorphisms of the human ATP binding cassette subfamily B member 1 (ABCB1) gene and opioid response has attracted intense attention recently....
The association between polymorphisms of the human ATP binding cassette subfamily B member 1 (ABCB1) gene and opioid response has attracted intense attention recently. As the ABCB1 gene encodes for the transporter P-glycoprotein in the brain and intestine involved in the pharmacokinetics of opioids, we investigated the effects of ABCB1 genetic polymorphisms on doses of opioids for pain relief and determined which pharmacokinetic process was affected in cancer pain patients. Sixty-eight cancer pain patients admitted for intrathecal therapy (ITT) were included. The association between ABCB1 genetic polymorphisms (C3435T, C1236T, G2677T/A and A61G) and systemic doses of opioids before ITT were investigated. Concentrations of oxycodone in plasma and cerebrospinal fluid (CSF) were determined by HPLC-MS/MS in 17 patients treated with oral oxycodone before ITT, and the influences of ABCB1 genetic polymorphisms on plasma-concentration to oral-dose ratios and CSF-concentration to plasma-concentration ratios of oral oxycodone were further analyzed. ABCB1 C3435T and G2677T/A polymorphisms were significantly associated with systemic doses of opioids before ITT, which coincided with the influences of ABCB1 C3435T and G2677T/A polymorphisms on the ratios of plasma-concentration to oral-dose. However, no significant difference was found in ratios of CSF-concentration to plasma-concentration among ABCB1 SNP genotypes. The present study provided the first evidence that ABCB1 C3435T and G2677T/A polymorphisms affect opioid requirement in cancer pain patients via altering transportation function of P-glycoprotein in the intestine, which will further expand our knowledge about pharmacokinetics of opioids and could contribute to the individualization of opioids use.
Topics: Humans; ATP Binding Cassette Transporter, Subfamily B; Male; Female; Analgesics, Opioid; Middle Aged; Polymorphism, Single Nucleotide; Aged; Oxycodone; Cancer Pain; Adult; ATP Binding Cassette Transporter, Subfamily B, Member 1; Intestinal Mucosa; Genotype
PubMed: 38850645
DOI: 10.1016/j.biopha.2024.116897 -
PloS One 2024Candesartan cilexetil (CC) is a selective angiotensin II receptor antagonist widely used to treat hypertension. CC is a substrate of P-glycoprotein (P-gp), causing its...
BACKGROUND
Candesartan cilexetil (CC) is a selective angiotensin II receptor antagonist widely used to treat hypertension. CC is a substrate of P-glycoprotein (P-gp), causing its efflux to the intestinal lumen. It is also practically insoluble in water and has low oral bioavailability (14%). Thus, the current study aims to improve the in vitro dissolution of CC by developing solid dispersion systems (SDSs) and corroborating the in vitro results using a simulated pharmacokinetics study.
METHODS
The SDSs were prepared using polyvinyl pyrrolidone (PVP) as a water-soluble polymer, Eudragit E100 (EE100) as a pH-dependent soluble carrier, and a combination of these two polymers. The saturation solubility and the dissolution rate studies of the prepared systems in three dissolution media were performed. The optimized system SE-EE5 was selected for further investigations, including DSC, XRD, FTIR, FESEM, DLS, TSEM, IVIVC convolution study, and stability studies.
RESULTS
The solubility of CC significantly increased by a factor of 27,037.344 when formulated as a solid dispersion matrix using EE100 at a ratio of 1:5 (w/w) drug to polymer (SE-EE5 SD), compared to the solubility of the pure drug. The mechanism of solubility and dissolution rate enhancement of CC by the optimized SDS was found to be via the conversion of the crystalline CC into the amorphous form as well as nanoparticles formation upon dissolution at a pH below 5. The instrumental analysis tests showed good compatibility between CC and EE100 and there was no chemical interaction between the drug and the polymer. Moreover, the stability tests confirmed that the optimized system was stable after three months of storage at 25°C.
CONCLUSION
The utilization of the solid dispersion technique employing EE 100 polymer as a matrix demonstrates significant success in enhancing the solubility, dissolution, and subsequently, the bioavailability of water-insoluble drugs like CC.
Topics: Benzimidazoles; Tetrazoles; Solubility; Biphenyl Compounds; Polymers; Povidone; Water; Hydrogen-Ion Concentration; Biological Availability; Drug Stability; Drug Liberation; Acrylates
PubMed: 38843120
DOI: 10.1371/journal.pone.0303900 -
Cancer Drug Resistance (Alhambra,... 2024Multidrug resistance (MDR) is frequent in non-small cell lung cancer (NSCLC) patients, which can be due to its fibrotic stroma. This work explores the combination of...
Multidrug resistance (MDR) is frequent in non-small cell lung cancer (NSCLC) patients, which can be due to its fibrotic stroma. This work explores the combination of pentoxifylline, an anti-fibrotic and chitinase 3-like-1 (CHI3L1) inhibitor drug, with conventional chemotherapy to improve NSCLC treatment. The effect of pentoxifylline in the expression levels of P-glycoprotein (P-gp), CHI3L1 and its main downstream proteins, as well as on cell death, cell cycle profile, and P-gp activity was studied in two pairs of sensitive and MDR counterpart NSCLC cell lines (NCI-H460/NCI-H460/R and A549/A549-CDR2). Association studies between gene expression and NSCLC patients' survival were performed using The Cancer Genome Atlas (TCGA) analysis. The sensitizing effect of pentoxifylline to different drug regimens was evaluated in both sensitive and MDR NSCLC cell lines. The cytotoxicity of the drug combinations was assessed in MCF10A non-tumorigenic cells. Pentoxifylline slightly decreased the expression levels of CHI3L1, β-catenin and signal transducer and activator of transcription 3 (STAT3), and caused a significant increase in the G1 phase of the cell cycle in both pairs of NSCLC cell lines. A significant increase in the % of cell death was observed in the sensitive NCI-H460 cell line. TCGA analysis revealed that high levels of CHI3L1 are associated with low overall survival (OS) in NSCLC patients treated with vinorelbine. Moreover, pentoxifylline sensitized both pairs of sensitive and MDR NSCLC cell lines to the different drug regimens, without causing significant toxicity to non-tumorigenic cells. This study suggests the possibility of combining pentoxifylline with chemotherapy to increase NSCLC therapeutic response, even in cases of MDR.
PubMed: 38835347
DOI: 10.20517/cdr.2024.04 -
Cureus May 2024(kratom) is a tropical tree native to Southeast Asia with dose-dependent stimulant and opioid properties. Kratom has garnered attention due to its increasing popularity...
(kratom) is a tropical tree native to Southeast Asia with dose-dependent stimulant and opioid properties. Kratom has garnered attention due to its increasing popularity and potential for dependence, tolerance, and withdrawal. We report the case of a 72-year-old man admitted to the hospital for a deep vein thrombosis and obstructive uropathy who began experiencing kratom withdrawal. He experienced less cravings and improvement in withdrawal symptoms with buprenorphine-naloxone 8 mg/2 mg daily. Notably, our case highlights kratom's contributions to a medically complex presentation and potential kratom-drug interactions due to its posited inhibitory effect on cytochrome P450 enzymes and P-glycoprotein. Our case adds to the growing literature which describes buprenorphine-naloxone as an effective treatment for kratom dependence and withdrawal.
PubMed: 38832209
DOI: 10.7759/cureus.59650