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International Journal of Molecular... Apr 2024Throughout its lifecycle, encounters a variety of stressful conditions. This parasite possesses Heat Shock Response Elements (HSEs) which are crucial for regulating the...
Throughout its lifecycle, encounters a variety of stressful conditions. This parasite possesses Heat Shock Response Elements (HSEs) which are crucial for regulating the expression of various genes, aiding in its adaptation and survival. These HSEs are regulated by Heat Shock Transcription Factors (EhHSTFs). Our research has identified seven such factors in the parasite, designated as EhHSTF1 through to EhHSTF7. Significantly, under heat shock conditions and in the presence of the antiamoebic compound emetine, EhHSTF5, EhHSTF6, and EhHSTF7 show overexpression, highlighting their essential role in gene response to these stressors. Currently, only EhHSTF7 has been confirmed to recognize the HSE as a promoter of the gene (HSE_), leaving the binding potential of the other EhHSTFs to HSEs yet to be explored. Consequently, our study aimed to examine, both in vitro and in silico, the oligomerization, and binding capabilities of the recombinant EhHSTF5 protein (rEhHSTF5) to HSE_. The in vitro results indicate that the oligomerization of rEhHSTF5 is concentration-dependent, with its dimeric conformation showing a higher affinity for HSE_ than its monomeric state. In silico analysis suggests that the alpha 3 α-helix (α3-helix) of the DNA-binding domain (DBD5) of EhHSTF5 is crucial in binding to the major groove of HSE, primarily through hydrogen bonding and salt-bridge interactions. In summary, our results highlight the importance of oligomerization in enhancing the affinity of rEhHSTF5 for HSE_ and demonstrate its ability to specifically recognize structural motifs within HSE_. These insights significantly contribute to our understanding of one of the potential molecular mechanisms employed by this parasite to efficiently respond to various stressors, thereby enabling successful adaptation and survival within its host environment.
Topics: Binding Sites; Computer Simulation; Entamoeba histolytica; Heat-Shock Response; Promoter Regions, Genetic; Protein Binding; Protein Multimerization; Protozoan Proteins; Response Elements; Transcription Factors; ATP Binding Cassette Transporter, Subfamily B, Member 1
PubMed: 38673804
DOI: 10.3390/ijms25084218 -
The Journal of Pharmacology and... Apr 2024Histone deacetylase expression and activity are often dysregulated in central nervous system (CNS) tumors, providing a rationale for investigating histone deacetylase...
Histone deacetylase expression and activity are often dysregulated in central nervous system (CNS) tumors, providing a rationale for investigating histone deacetylase inhibitors (HDACIs) in selected brain tumor patients. Although many HDACIs have shown potential in studies, they have had modest efficacy This lack of activity could be due to insufficient CNS exposure to the unbound drug. In this study, we investigated the systemic pharmacokinetics and subsequent CNS distribution of two potent HDACIs, vorinostat and quisinostat, in the murine model. Both compounds undergo degradation in mouse plasma, requiring precautions during sample processing. They also have short half-lives , in both plasma and CNS, which may lead to diminished efficacy. Transgenic transporter-deficient mouse models show that the CNS delivery of vorinostat was not limited by the two major blood-brain barrier efflux transporters, p-glycoprotein and breast-cancer-resistance protein. Vorinostat had an unbound CNS tissue-to-plasma partition coefficient of 0.06 {plus minus} 0.02. Conversely, the exposure of unbound quisinostat in the brain was only 0.02 {plus minus} 0.001 of that in the plasma, and the CNS distribution of quisinostat was limited by the activity of p-glycoprotein. To gain further context for these findings, the CNS distributional kinetics for vorinostat and quisinostat were compared to another hydroxamic acid HDACI, panobinostat. A comprehensive understanding of the CNS target exposure to unbound HDACI, along with known potencies from testing, can inform the prediction of a therapeutic window for HDACIs that have limited CNS exposure to unbound drug and guide targeted dosing strategies. This study indicates that quisinostat and vorinostat are susceptible to enzymatic degradation in the plasma, and to a lesser degree, in the target CNS tissues. Employing techniques that minimize the post-sampling degradation in plasma, brain and spinal cord, accurate CNS distributional kinetic parameters for these potentially useful compounds were determined. A knowledge of CNS exposure (K), time to peak, and duration can inform dosing strategies in preclinical and clinical trials in selected CNS tumors.
PubMed: 38670802
DOI: 10.1124/jpet.124.002170 -
Biochemia Medica Jun 2024Considering conflicting previous reports, we aimed to evaluate whether the common polymorphisms (rs1128503, rs2032582, rs1045642, rs4148738) affected the risk of...
INTRODUCTION
Considering conflicting previous reports, we aimed to evaluate whether the common polymorphisms (rs1128503, rs2032582, rs1045642, rs4148738) affected the risk of bleeding in rivaroxaban-treated patients.
MATERIALS AND METHODS
We report preliminary data from a larger nested case-control study. Consecutive adults started on rivaroxaban for any indication requiring > 6 months of treatment were followed-up to one year. Patients who experienced major or non-major clinically relevant bleeding during the initial 6 months were considered cases, whereas subjects free of bleeding over > 6 months were controls. The polymorphisms of interest (rs1128503, rs2032582, rs1045642, rs4148738) were in a strong linkage disequilibrium, hence patients were classified regarding the "load" of variant alleles: 0-2, 3-5 or 6-8. The three subsets were balanced regarding a range of demographic, comorbidity, comedication and genetic characteristics. A logistic model was fitted to probability of bleeding.
RESULTS
There were 60 cases and 220 controls. Raw proportions of cases were similar across the subsets with increasing number of variant alleles (0-2, N = 85; 3-6, N = 133; 6-8, N = 62): 22.4%, 21.8%, and 19.4%, respectively. Fully adjusted probabilities of bleeding were also similar across the subsets: 22.9%, 27.5% and 17.7%, respectively. No trend was observed (linear, t = -0.63, df = 273, P = 0.529; quadratic, t = -1.10, df = 273, P = 0.272). Of the 15 identified haplotypes, the completely variant (c.1236T_c.2677T(A)_c.3435T_c.2482-2236A) (40.7%) and completely wild-type (C_G_C_G) (39.5%) haplotypes prevailed, and had a closely similar prevalence of cases: 21.1% . 23.1%, respectively.
CONCLUSIONS
The evaluated common polymorphisms do not seem to affect the risk of early bleeding in patients started on rivaroxaban.
Topics: Humans; Rivaroxaban; ATP Binding Cassette Transporter, Subfamily B; Male; Female; Case-Control Studies; Aged; Middle Aged; Hemorrhage; Polymorphism, Single Nucleotide; Factor Xa Inhibitors; Risk Factors
PubMed: 38665866
DOI: 10.11613/BM.2024.020703 -
RSC Medicinal Chemistry Apr 2024Multidrug resistance (MDR) remains a challenging issue in cancer treatment. Aiming at finding anticancer agents to overcome MDR, the triacetyl derivative (2) of the...
Multidrug resistance (MDR) remains a challenging issue in cancer treatment. Aiming at finding anticancer agents to overcome MDR, the triacetyl derivative (2) of the labdane diterpenoid lactone andrographolide (1) underwent the Michael-type addition reaction followed by elimination, yielding twenty-three new derivatives, bearing nitrogen-containing substituents (3-25). Their structures were assigned, mainly, by 1D and 2D NMR experiments. The MDR reversal potential of compounds 1-25 was assessed, by functional and chemosensitivity assays, using resistant human -gene transfected L5178Y mouse lymphoma cells as a model. Several derivatives exhibited remarkable P-glycoprotein (P-gp) inhibitory ability. Compounds 13 and 20, bearing thiosemicarbazide moieties, were the most active exhibiting a strong MDR reversal effect at 2 μM. Some compounds showed selectivity towards the resistant cells, with compound 5 exhibiting a collateral sensitivity effect associated with significant antiproliferative activity (IC = 5.47 ± 0.22 μM). Moreover, all selected compounds displayed synergistic interaction with doxorubicin, with compound 3 being the most active. In the ATPase assay, selected compounds exhibited characteristics of P-gp inhibitors.
PubMed: 38665830
DOI: 10.1039/d3md00711a -
Frontiers in Biophysics 2024P-glycoprotein (Pgp) is known for its dichotomous roles as both a safeguarding efflux transporter against xenobiotics and as a catalyst for multidrug resistance. Given...
P-glycoprotein (Pgp) is known for its dichotomous roles as both a safeguarding efflux transporter against xenobiotics and as a catalyst for multidrug resistance. Given the susceptibility of numerous therapeutic compounds to Pgp-mediated resistance, compliance with Food and Drug Administration (FDA) guidelines mandates an in-depth transport assay during drug development. This study introduces an innovative transport assay that aligns with these regulatory imperatives but also addresses limitations in the currently established techniques. Using Pgp-reconstituted liposomes and employing surface plasmon resonance (SPR), this study developed a distinct method of measuring the relative transport rates of Pgp substrates in a controlled microenvironment. The Pgp substrates selected for this study-quinidine, methadone, and desipramine-resulted in transport ratios that corroborate with trends previously observed. To assess the kinetics of Pgp-mediated transport, the results were analyzed by fitting the data to both currently proposed Pgp substrate translocation models-the vacuum cleaner and flippase models. While the resulting kinetic analysis in this study lends support predominantly to the vacuum cleaner model, this study most notably developed a novel method of assessing Pgp-mediated transport rates and real-time kinetics using surface plasmon resonance.
PubMed: 38645731
DOI: 10.3389/frbis.2024.1367511 -
International Journal of Pharmaceutics May 2024While various non-ionic surfactants at low concentrations have been shown to increase the transport of P-gp substrates in vitro, in vivo studies in rats have shown that...
While various non-ionic surfactants at low concentrations have been shown to increase the transport of P-gp substrates in vitro, in vivo studies in rats have shown that a higher surfactant concentration is needed to increase the oral absorption of e.g. the P-gp substrates digoxin and etoposide. The aim of the present study was to investigate if intestinal digestion of surfactants could be the reason for this deviation between in vitro and in vivo data. Therefore, Kolliphor EL, Brij-L23, Labrasol and polysorbate 20 were investigated for their ability to inhibit P-gp and increase digoxin absorption in vitro. Transport studies were performed in Caco-2 cells, while P-gp inhibition and cell viability assays were performed in MDCKII-MDR1 cells. Polysorbate 20, Kolliphor EL and Brij-L23 increased absorptive transport and decreased secretory digoxin transport in Caco-2 cells, whereas only polysorbate 20 and Brij-L23 showed P-gp inhibiting properties in the MDCKII-MDR1 cells. Polysorbate 20 and Brij-L23 were chosen for in vitro digestion prior to transport- or P-gp inhibiting assays. Brij-L23 was not digestible, whereas polysorbate 20 reached a degree of digestion around 40%. Neither of the two surfactants showed any significant difference in their ability to affect absorptive or secretory transport of digoxin after pre-digestion. Furthermore, the P-gp inhibiting effects of polysorbate 20 were not decreased significantly. In conclusion, the mechanism behind the non-ionic surfactant mediated in vitro P-gp inhibition seemed independent of the intestinal digestion and the results presented here did not suggest it to be the cause of the observed discrepancy between in vitro and in vivo.
Topics: Animals; Dogs; Humans; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Caco-2 Cells; Cell Survival; Digestion; Digoxin; Glycerides; Intestinal Absorption; Madin Darby Canine Kidney Cells; Polysorbates; Surface-Active Agents
PubMed: 38621613
DOI: 10.1016/j.ijpharm.2024.124120 -
Clinical Pharmacokinetics Apr 2024Enfortumab vedotin is an antibody-drug conjugate comprised of a human monoclonal antibody directed to Nectin-4 and monomethyl auristatin E (MMAE), a... (Review)
Review
Enfortumab vedotin is an antibody-drug conjugate comprised of a human monoclonal antibody directed to Nectin-4 and monomethyl auristatin E (MMAE), a microtubule-disrupting agent. The objectives of this review are to summarize the clinical pharmacology of enfortumab vedotin monotherapy and demonstrate that the appropriate dose has been selected for clinical use. Pharmacokinetics (PK) of enfortumab vedotin (antibody-drug conjugate and total antibody) and free MMAE were evaluated in five clinical trials of patients with locally advanced or metastatic urothelial carcinoma (n = 748). Intravenous enfortumab vedotin 0.5-1.25 mg/kg on days 1, 8, and 15 of a 28-day cycle showed linear, dose-proportional PK. No significant differences in exposure or safety of enfortumab vedotin and free MMAE were observed in mild, moderate, or severe renal impairment versus normal renal function. Patients with mildly impaired versus normal hepatic function had a 37% increase in area under the concentration-time curve (0-28 days), a 31% increase in maximum concentration of free MMAE, and a similar adverse event profile. No clinically significant PK differences were observed based on race/ethnicity with weight-based dosing, and no clinically meaningful QT prolongation was observed. Concomitant use with dual P-glycoprotein and strong cytochrome P450 3A4 inhibitors may increase MMAE exposure and the risk of adverse events. Approximately 3% of patients developed antitherapeutic antibodies against enfortumab vedotin 1.25 mg/kg. These findings support enfortumab vedotin 1.25 mg/kg monotherapy on days 1, 8, and 15 of a 28-day cycle. No dose adjustments are required for patients with renal impairment or mild hepatic impairment, or by race/ethnicity.
Topics: Humans; Antibodies, Monoclonal; Immunoconjugates; Oligopeptides; Urologic Neoplasms; Dose-Response Relationship, Drug; Carcinoma, Transitional Cell; Antineoplastic Agents; Nectins
PubMed: 38609704
DOI: 10.1007/s40262-024-01369-0 -
Drug Safety Jul 2024Enzalutamide is an oral androgen receptor signaling inhibitor utilized in the treatment of men with prostate cancer. It is a moderate inducer of the cytochrome P450... (Review)
Review
Enzalutamide is an oral androgen receptor signaling inhibitor utilized in the treatment of men with prostate cancer. It is a moderate inducer of the cytochrome P450 (CYP) enzymes CYP2C9 and CYP2C19, and a strong inducer of CYP3A4. It was also shown to be a mild inhibitor of the efflux transporter P-glycoprotein in patients with prostate cancer. Enzalutamide is primarily metabolized by CYP3A4 and CYP2C8. The risk of enzalutamide drug interactions arises primarily when it is coadministered with other drugs that interact with these CYPs, including CYP3A4. In this review, we begin by providing an overview of enzalutamide including its dosing, use in special populations, pharmacokinetics, changes to its prescribing information, and potential for interaction with coadministered drugs. Enzalutamide interactions with drugs from a wide range of medication classes commonly prescribed to patients with prostate cancer are described, including oral androgen deprivation therapy, agents used to treat a range of cardiovascular diseases, antidiabetic drugs, antidepressants, anti-seizure medications, common urology medications, analgesics, proton pump inhibitors, immunosuppressants, and antigout drugs. Enzalutamide interactions with common vitamins and supplements are also briefly discussed. This review provides a resource for healthcare practitioners and patients that will help provide a basis for the understanding and management of enzalutamide drug-drug interactions to inform decision making, improve patient safety, and optimize drug efficacy.
Topics: Humans; Drug Interactions; Phenylthiohydantoin; Nitriles; Benzamides; Male; Patient Safety; Prostatic Neoplasms; Antineoplastic Agents
PubMed: 38607520
DOI: 10.1007/s40264-024-01415-7 -
Cureus Mar 2024Ivermectin was first discovered in the 1970s by Japanese microbiologist Satoshi Omura and Irish parasitologist William C. Campbell. Ivermectin has become a versatile... (Review)
Review
Ivermectin was first discovered in the 1970s by Japanese microbiologist Satoshi Omura and Irish parasitologist William C. Campbell. Ivermectin has become a versatile pharmaceutical over the past 50 years. Ivermectin is a derivative of avermectin originally used to treat parasitic infections. Emerging literature has suggested that its role goes beyond this and may help treat inflammatory conditions, viral infections, and cancers. Ivermectin's anti-parasitic, anti-inflammatory, anti-viral, and anticancer effects were explored. Its traditional mechanism of action in parasitic diseases, such as scabies and malaria, rests on its ability to interfere with the glutamate-gated chloride channels in invertebrates and the lack of P-glycoprotein in many parasites. More recently, it has been discovered that the ability of ivermectin to block the nuclear factor kappa-light-chain enhancer of the activated B (NF-κB) pathway that modulates the expression and production of proinflammatory cytokines is implicated in its role as an anti-inflammatory agent to treat rosacea. Ivermectin has also been evaluated for treating infections caused by viruses, such as SARS-CoV-2 and adenoviruses, through inhibition of viral protein transportation and acting on the importin α/β1 interface. It has also been suggested that ivermectin can inhibit the proliferation of tumorigenic cells through various pathways that lead to the management of certain cancers. The review aimed to evaluate its multifaceted effects and potential clinical applications beyond its traditional use as an anthelmintic agent.
PubMed: 38606261
DOI: 10.7759/cureus.56025 -
Fluids and Barriers of the CNS Apr 2024The blood-brain barrier (BBB) serves as a highly intricate and dynamic interface connecting the brain and the bloodstream, playing a vital role in maintaining brain...
The blood-brain barrier (BBB) serves as a highly intricate and dynamic interface connecting the brain and the bloodstream, playing a vital role in maintaining brain homeostasis. BBB dysfunction has been associated with multiple neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS); however, the role of the BBB in neurodegeneration is understudied. We developed an ALS patient-derived model of the BBB by using cells derived from 5 patient donors carrying C9ORF72 mutations. Brain microvascular endothelial-like cells (BMEC-like cells) derived from C9ORF72-ALS patients showed altered gene expression, compromised barrier integrity, and increased P-glycoprotein transporter activity. In addition, mitochondrial metabolic tests demonstrated that C9ORF72-ALS BMECs display a significant decrease in basal glycolysis accompanied by increased basal and ATP-linked respiration. Moreover, our study reveals that C9-ALS derived astrocytes can further affect BMECs function and affect the expression of the glucose transporter Glut-1. Finally, C9ORF72 patient-derived BMECs form leaky barriers through a cell-autonomous mechanism and have neurotoxic properties towards motor neurons.
Topics: Humans; Amyotrophic Lateral Sclerosis; Blood-Brain Barrier; C9orf72 Protein; Endothelial Cells
PubMed: 38605366
DOI: 10.1186/s12987-024-00528-6