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1.	Artursson, Magnus, et al. (författare) Aspekter på samhällsutveckling 2005 Ingår i: Bronsåldersbygd 2300-500 f. Kr.. - 1650-2787. - 9172093765 ; , s. 496-547 Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract ... Den förändringsprocess som vi här har försökt åskådliggöra är nära knuten till en förändring av ideologi och mentalitet, där den tidigare kollektivt präglade ideologin försvagades och successivt öppnade upp för en ökad stratifiering av samhället. Det finns tydliga tendenser i det arkeologiska materialet mot en ökad betoning och uppvisning av politisk, ekonomisk och militär makt. Denna demonstration av makt når sitt maximum under bronsålderns period II, 1500-1300 f. Kr., då de materiella lämningarna visar att man lagt en stor betydelse vid visuell och rituell uppvisning av hög social position ...
2.	Borhade, Sanjay R., et al. (författare) Preclinical Characterization of Acyl Sulfonimidamides : Potential Carboxylic Acid Bioisosteres with Tunable Properties 2015 Ingår i: ChemMedChem. - : Wiley. - 1860-7179 .- 1860-7187. ; 10:3, s. 455-460 Tidskriftsartikel (refereegranskat)abstract Herein we present the preclinical characterization of novel compounds containing the linear acyl sulfonimidamide functionality. Specifically, we studied the pK(a), lipophilicity, in vitro metabolic stability, plasma protein binding, Caco-2 permeability, and aqueous solubility for nine aryl acyl sulfonimidamides. In comparison with widely used carboxylic acid bioisosteres, the acyl sulfonimidamides were found to be less acidic and more lipophilic depending on the substitution pattern in the studied compounds. Importantly, the pKa values (5.9-7.6) were significantly influenced by substituents on the nitrogen atom and the aryl substituents. Moreover, the acyl sulfonimidamides displayed membrane permeabilities ranging from moderate to very high, which correlated with decreased pKa and low to negligible efflux ratios. We foresee that the chiral sulfur center and the two handles for structural diversity of linear acyl sulfonimidamides will offer new opportunities for drug design and for improving the oral bioavailability of acidic drug candidates.
3.	Bose, Partha Pratim, et al. (författare) In vitro ADMET and physicochemical investigations of poly-N-methylated peptides designed to inhibit Aβ aggregation 2010 Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 18:16, s. 5896-5902 Tidskriftsartikel (refereegranskat)abstract N-Methylation is a common strategy for improving oral bioavailability of peptide-based lead structures. Herein, we present a detailed study on how the degree of N-methylation affects the absorption-distribution-metabolism-excretion-toxicity (ADMET) properties such as solubility, membrane transport, proteolytic stability, and general cell toxicity of the investigated peptides. As representative structures we chose hexapeptides 1-8. These peptides, corresponding to N-methylated analogues of residues 16-21 and 32-37 of the Abeta-peptide, pathological hallmark of Alzheimer's disease (AD), have previously been shown to inhibit aggregation of Abeta fibrils in vitro. This study suggests that poly-N-methylated peptides are non-toxic and have enhanced proteolytic stability over their non-methylated analogues. Furthermore, solubility in aqueous solution is seen to increase with increased degree of N-methylation, while membrane transport was found to be low for all investigated hexapeptides. The present results, together with those reported in the literature, suggest that poly-N-methylated peptides, especially shorter or equal to six residues, can be suitable candidates for drug design.
4.	Caraballo, Remi, et al. (författare) Structure-activity relationships for lipoprotein lipase agonists that lower plasma triglycerides in vivo 2015 Ingår i: European Journal of Medicinal Chemistry. - : Elsevier. - 0223-5234 .- 1768-3254. ; 103, s. 191-209 Tidskriftsartikel (refereegranskat)abstract The risk of cardiovascular events increases in individuals with elevated plasma triglyceride (TG) levels, therefore advocating the need for efficient TG-lowering drugs. In the blood circulation, TG levels are regulated by lipoprotein lipase (LPL), an unstable enzyme that is only active as a non-covalently associated homodimer. We recently reported on a N-phenylphthalimide derivative (1) that stabilizes LPL in vitro, and moderately lowers triglycerides in vivo (Biochem. Biophys. Res. Common. 2014, 450, 1063). Herein, we establish structure activity relationships of 51 N-phenylphthalimide analogs of the screening hit 1. In vitro evaluation highlighted that modifications on the phthalimide moiety were not tolerated and that lipophilic substituents on the central phenyl ring were functionally essential. The substitution pattern on the central phenyl ring also proved important to stabilize LPL However, in vitro testing demonstrated rapid degradation of the phthalimide fragment in plasma which was addressed by replacing the phthalimide scaffold with other heterocyclic fragments. The in vitro potency was retained or improved and substance 80 proved stable in plasma and efficiently lowered plasma TGs in vivo. 2015 The Authors. Published by Elsevier Masson SAS.
5.	Hubatsch, Ina, et al. (författare) Beta- and gamma-di- and tripeptides as potential substrates for the oligopeptide transporter hPepT1 2007 Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 50:21, s. 5238-5242 Tidskriftsartikel (refereegranskat)abstract The hPepT1-mediated transport properties of a series of 11 synthesized beta- and gamma-peptides have been studied in Caco-2 cells. The results show that several of the compounds interact with the peptide transporter, but only two beta-dipeptides act as substrates and are transported across the cell monolayers. These two are less-efficient substrates than alfa-peptides. Larger derivatives than beta-dipeptides do not act as hPepT1 substrates, but instead, they appear to be substrates for P-glycoprotein efflux.
6.	Lundquist, Patrik, et al. (författare) Barriers to the Intestinal Absorption of Four Insulin-Loaded Arginine-Rich Nanoparticles in Human and Rat 2022 Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 16:9, s. 14210-14229 Tidskriftsartikel (refereegranskat)abstract Peptide drugs and biologics provide opportunities for treatments of many diseases. However, due to their poor stability and permeability in the gastrointestinal tract, the oral bioavailability of peptide drugs is negligible. Nanoparticle formulations have been proposed to circumvent these hurdles, but systemic exposure of orally administered peptide drugs has remained elusive. In this study, we investigated the absorption mechanisms of four insulin-loaded arginine-rich nanoparticles displaying differing composition and surface characteristics, developed within the pan-European consortium TRANS-INT. The transport mechanisms and major barriers to nanoparticle permeability were investigated in freshly isolated human jejunal tissue. Cytokine release profiles and standard toxicity markers indicated that the nanoparticles were nontoxic. Three out of four nanoparticles displayed pronounced binding to the mucus layer and did not reach the epithelium. One nanoparticle composed of a mucus inert shell and cell-penetrating octarginine (ENCP), showed significant uptake by the intestinal epithelium corresponding to 28 ± 9% of the administered nanoparticle dose, as determined by super-resolution microscopy. Only a small fraction of nanoparticles taken up by epithelia went on to be transcytosed via a dynamin-dependent process. In situ studies in intact rat jejunal loops confirmed the results from human tissue regarding mucus binding, epithelial uptake, and negligible insulin bioavailability. In conclusion, while none of the four arginine-rich nanoparticles supported systemic insulin delivery, ENCP displayed a consistently high uptake along the intestinal villi. It is proposed that ENCP should be further investigated for local delivery of therapeutics to the intestinal mucosa.
7.	Taipalensuu, Jan, et al. (författare) Correlation of gene expression of ten drug efflux proteins of the ATP-binding cassette transporter family in normal human jejunum and inhuman intestinal epithelial Caco-2 cell monolayers 2001 Ingår i: Journal of Pharmacology and Experimental Therapeutics. - 0022-3565 .- 1521-0103. ; 299:1, s. 164-170 Tidskriftsartikel (refereegranskat)abstract This investigation describes the expression and interindividual variability in transcript levels of multiple drug efflux systems in the human jejunum and compares the expression profiles in these cells with that of the commonly used Caco-2 cell drug absorption model. Transcript levels of ten-drug efflux proteins of the ATP-binding cassette (ABC) transporter family [MDR1, MDR3, ABCB5, MRP1-6, and breast cancer resistance protein (BCRP)], lung resistance-related protein (LRP), and CYP3A4 were determined using quantitative polymerase chain reaction in jejunal biopsies from 13 healthy human subjects and in Caco-2 cells. All genes except ABCB5 were expressed, and transcript levels varied between individuals only by a factor of 2 to 3. Surprisingly, BCRP and MRP2 transcripts were more abundant in jejunum than MDR1 transcripts. Jejunal transcript levels of the different ABC transporters spanned a range of three log units with the rank order: BCRP approximately MRP2 > MDR1 approximately MRP3 approximately MRP6 approximately MRP5 approximately MRP1 > MRP4 > MDR3. Furthermore, transcript levels of 9 of 10 ABC transporters correlated well between jejunum and Caco-2 cells (r2 = 0.90). However, BCRP exhibited a 100-fold lower transcript level in Caco-2 cells compared with jejunum. Thus, the expression of a number of efflux protein transcripts in jejunum are equal to, or even higher than, that of MDR1, suggesting that the roles of these proteins (in particular BCRP and MRP2) in intestinal drug efflux have been underestimated. Also, we tentatively conclude that the Caco-2 cell line is a useful model of jejunal drug efflux, if the low expression of BCRP is taken into account.
8.	Tremmel, Roman, et al. (författare) Hepatic Expression of the Na+-Taurocholate Cotransporting Polypeptide Is Independent from Genetic Variation 2022 Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 23:13 Tidskriftsartikel (refereegranskat)abstract The hepatic Na+-taurocholate cotransporting polypeptide NTCP/SLC10A1 is important for the uptake of bile salts and selected drugs. Its inhibition results in increased systemic bile salt concentrations. NTCP is also the entry receptor for the hepatitis B/D virus. We investigated interindividual hepatic SLC10A1/NTCP expression using various omics technologies. SLC10A1/NTCP mRNA expression/protein abundance was quantified in well-characterized 143 human livers by real-time PCR and LC-MS/MS-based targeted proteomics. Genome-wide SNP arrays and SLC10A1 next-generation sequencing were used for genomic analyses. SLC10A1 DNA methylation was assessed through MALDI-TOF MS. Transcriptomics and untargeted metabolomics (UHPLC-Q-TOF-MS) were correlated to identify NTCP-related metabolic pathways. SLC10A1 mRNA and NTCP protein levels varied 44-fold and 10.4-fold, respectively. Non-genetic factors (e.g., smoking, alcohol consumption) influenced significantly NTCP expression. Genetic variants in SLC10A1 or other genes do not explain expression variability which was validated in livers (n = 50) from The Cancer Genome Atlas. The identified two missense SLC10A1 variants did not impair transport function in transfectants. Specific CpG sites in SLC10A1 as well as single metabolic alterations and pathways (e.g., peroxisomal and bile acid synthesis) were significantly associated with expression. Inter-individual variability of NTCP expression is multifactorial with the contribution of clinical factors, DNA methylation, transcriptional regulation as well as hepatic metabolism, but not genetic variation.
9.	Tremmel, Roman, et al. (författare) Non-genetic and epigenetic factors contribute to inter-individualvariability of the hepatic bile acid and drug transporter NTCP : Hepatic variability of the hepatic bile acid and drug transporter NTCP Annan publikation (övrigt vetenskapligt/konstnärligt)abstract Background and Purpose: The hepatic Na+-taurocholate cotransporting polypeptide NTCP/SLC10A1 plays an importantrole in the uptake of bile salts and drugs, and as key receptor for hepatitis B/D virus entry. NTCPinhibitors are investigated for treatment of HBV/HDV-infection. We performed a comprehensivemulti-omics approach to investigate underlying mechanisms of inter-individual variability ofNTCP expression in Caucasians.Experimental Approach: mRNA/protein expression of SLC10A1/NTCP was quantified in 143 well-characterized nontumorhuman liver samples by real-time PCR and LC-MS/MS-based targeted proteomics,respectively. Genetic variants were investigated using genome-wide SNP arrays and nextgenerationsequencing. DNA methylation of the SLC10A1 promoter region was investigatedthrough MALDI-TOF MS. Untargeted metabolomics of liver tissues was performed by UHPLC-QTOFMS.Key Results: The SLC10A1 mRNA expression showed a 44-fold variation in liver samples, whereas NTCPprotein expression varied 10.4-fold. Genome-wide association analyses and in-depth SLC10A1sequencing indicates that genetic variants either in SLC10A1 or other genes, cannot explainexpression variability. Only two missense SLC10A1 variants were identified. NTCP proteinexpression is significantly influenced by non-genetic factors (e.g. smoking, alcoholconsumption). DNA methylation analysis revealed a significant association of specific CpG-siteswith protein expression (p<0.05). Additionally, variable expression is associated with metabolicalterations determined through gene set enrichment and untargeted metabolomics. Findingswere validated partly in livers (n=50) from The Cancer Genome Atlas.Conclusion and Implications: Inter-individual variability of NTCP expression is multifactorial with a significant contribution ofDNA methylation. Functional genetic variants are negligible and may not limit targeting of NTCPby novel inhibitors for treatment of HBV/HDV-infection.
10.	Unéus, Lars, 1971-, et al. (författare) Evaluation of on-line flue gas measurements by MISiCFET and metal-oxide sensors in boilers 2005 Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 5:1, s. 75-81 Tidskriftsartikel (refereegranskat)abstract Metal insulator silicon carbide field-effect transistor sensors, metal-oxide sensors, and a linear Lambda sensor in an electronic nose was used to measure on-line in hot flue gases from a boiler. Flue gas from a 100-MW pellets-fuelled boiler has been used to feed the experimental setup. Several reference instruments, which measure the flue gases in parallel to the sensor array, are connected to the electronic nose. Data was collected during six weeks and then evaluated. Using principal component analysis as the data evaluation method, different operating modes for the boiler have been identified in the data set. The different modes could be described in terms of high or low O 2 and CO concentration. Furthermore, we have shown that it seems possible to use a sensor array to determine the operating mode of the boiler and, by partial least-squares models, measure the CO concentration when the boiler operates in its optimum mode.
11.	Ahlin, Gustav, 1977-, et al. (författare) Endogenous Gene and Protein Expression of Drug Transporting Proteins in Cell Lines Routinely used in Drug Discovery Programs 2009 Ingår i: Drug Metabolism And Disposition. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0090-9556 .- 1521-009X. ; 37:12, s. 2275-2283 Tidskriftsartikel (refereegranskat)abstract The aim of this study was to investigate the gene and protein expression profiles of important drug transporting proteins in human cell lines commonly used for studies of drug transport mechanisms. Human cell lines used to transiently or stably express single transporters (HeLa, HEK293) and leukaemia cell lines used to study drug resistance by ABC-transporters (HL-60, K562) were investigated, and compared with organotypic cell lines (HepG2, Saos-2, Caco-2 and Caco-2 TC7). For gene expression studies, real-time PCR was used, while monospecific polyclonal antibodies were generated and used to investigate protein expression by immunohistochemistry. Thirty-six transporters were studied for gene expression and nine for protein expression. The antibodies were validated using expression patterns in human tissues. Finally, the function of one ubiquitously expressed transporter, MCT1; SLC16A1 was investigated using 14C-lactic acid as a substrate. In general, the adherent cell lines (HeLa, HEK293) displayed low transporter expression and the expression patterns were barely affected by transfection. The leukaemia cell lines (K562, HL-60) and Saos-2 also had low endogenous transporter expression, while the organotypic cell lines (HepG2 and Caco-2) showed higher expression of some transporters. Comparison of gene and protein expression profiles gave poor correlations, but better agreement was obtained for antibodies with a good validation score, indicating that antibody quality was a significant variable. Importantly, the monocarboxylic acid transporting protein MCT1 was significantly expressed in all, and functional in most of the cell lines, indicating that MCT1 may be a confounding factor when the transport of small anionic drugs is investigated.
12.	Ahlin, Gustav, 1977-, et al. (författare) Genotype-dependent effects of inhibitors of the organic cation transporter, OCT1: : predictions of metformin interactions 2011 Ingår i: The Pharmacogenomics Journal. - : Springer Science and Business Media LLC. - 1470-269X .- 1473-1150. ; 11:6, s. 400-411 Tidskriftsartikel (refereegranskat)abstract Common genetic variants of the liver-specific human organic cation transporter 1 (OCT1; SLC22A1) have reduced transport capacity for substrates such as the antidiabetic drug metformin. The effect of the reduced OCT1 function on drug interactions associated with OCT1 has not been investigated and was, therefore, the focus of the study presented here. HEK293 cells expressing human OCT1-reference or the variants R61C, V408M, M420del and G465R were first used to study the kinetics and inhibition pattern of the OCT1 substrate 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP(+)). In the second part OCT1-mediated (14)C-metformin uptake was studied in the presence of drugs administered concomitantly with metformin. Transport studies using ASP(+) showed that the function of the variants decreased in the following order: OCT1-reference = V408M = M420del >R61C > >G465R. Variants M420del and R61C were more sensitive to drug inhibition, with IC(50) values up to 23 times lower than those of the OCT1-reference. Uptake studies using (14)C-metformin were in qualitative agreement with those using ASP(+), with the exception that a larger reduction in transport capacity was observed for M420del. Concomitantly administered drugs, such as verapamil and amitriptyline, revealed potential drug-drug interactions at clinical plasma concentrations of metformin for OCT1-M420del.
13.	Ahlin, Gustav, 1977- (författare) In vitro and in silico prediction of drug-drug interactions with transport proteins 2009 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Drug transport across cells and cell membranes in the human body is crucial for the pharmacological effect of drugs. Active transport governed by transport proteins plays an important role in this process. A vast number of transport proteins with a wide tissue distribution have been identified during the last 15 years. Several important examples of their role in drug disposition and drug-drug interactions have been described to date. Investigation of drug-drug interactions at the transport protein level are therefore of increasing interest to the academic, industrial and regulatory research communities. The gene expression of transport proteins involved in drug transport was investigated in the jejunum, liver, kidney and colon to better understand their influence on the ADMET properties of drugs. In addition, the gene and protein expression of transport proteins in cell lines, widely used for predictions of drug transport and metabolism, was examined. The substrate and inhibitor heterogeneity of many transport proteins makes it difficult to foresee whether the transport proteins will cause drug-drug interactions. Therefore, in vitro assays for OCT1 and OATP1B1, among the highest expressed transport proteins in human liver, were developed to allow investigation of the inhibitory patterns of these proteins. These assays were used to investigate two data sets, consisting of 191 and 135 registered drugs and drug-like molecules for the inhibition of OCT1 and OATP1B1, respectively. Numerous new inhibitors of the transport proteins were identified in the data sets and the properties governing inhibition were determined. Further, antidepressant drugs and statins displayed strong inhibition of OCT1 and OATP1B1, respectively. The inhibition data was used to develop predictive in silico models for each of the two transport proteins. The highly polymorphic nature of some transport proteins has been shown to affect drug response and may lead to an increased risk of drug-drug interactions, and therefore, the OCT1 in vitro assay was used to study the effect of common genetic variants of OCT1 on drug inhibition and drug-drug interactions. The results indicated that OCT1 variants with reduced function were more susceptible to inhibition. Further, a drug-drug interaction of potential clinical significance in the genetic OCT1 variant M420del was proposed. In summary, gene expression of transport proteins was investigated in human tissues and cell lines. In vitro assays for two of the highest expressed liver transport proteins were used to identify previously unknown SLC transport protein inhibitors and to develop predictive in silico models, which may detect previously known drug-drug interactions and enable new ones to be identified at the transport protein level. In addition, the effect of genetic variation on inhibition of the OCT1 was investigated.
14.	Ahlin, Gustav, et al. (författare) Structural requirements for drug inhibition of the liver specific human organic cation transport protein 1 2008 Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 51:19, s. 5932-5942 Tidskriftsartikel (refereegranskat)abstract The liver-specific organic cation transport protein (OCT1; SLC22A1) transports several cationic drugs including the antidiabetic drug metformin and the anticancer agents oxaliplatin and imatinib. In this study, we explored the chemical space of registered oral drugs with the aim of studying the inhibition pattern of OCT1 and of developing predictive computational models of OCT1 inhibition. In total, 191 structurally diverse compounds were examined in HEK293-OCT1 cells. The assay identified 47 novel inhibitors and confirmed 15 previously known inhibitors. The enrichment of OCT1 inhibitors was seen in several drug classes including antidepressants. High lipophilicity and a positive net charge were found to be the key physicochemical properties for OCT1 inhibition, whereas a high molecular dipole moment and many hydrogen bonds were negatively correlated to OCT1 inhibition. The data were used to generate OPLS-DA models for OCT1 inhibitors; the final model correctly predicted 82% of the inhibitors and 88% of the noninhibitors of the test set.
15.	Al-Amin, Rasel A., Researcher, 1983-, et al. (författare) Monitoring drug–target interactions through target engagement-mediated amplification on arrays and in situ 2022 Ingår i: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 50:22, s. e129-e129 Tidskriftsartikel (refereegranskat)abstract Drugs are designed to bind their target proteins in physiologically relevant tissues and organs to modulate biological functions and elicit desirable clinical outcomes. Information about target engagement at cellular and subcellular resolution is therefore critical for guiding compound optimization in drug discovery, and for probing resistance mechanisms to targeted therapies in clinical samples. We describe a target engagement-mediated amplification (TEMA) technology, where oligonucleotide-conjugated drugs are used to visualize and measure target engagement in situ, amplified via rolling-circle replication of circularized oligonucleotide probes. We illustrate the TEMA technique using dasatinib and gefitinib, two kinase inhibitors with distinct selectivity profiles. In vitro binding by the dasatinib probe to arrays of displayed proteins accurately reproduced known selectivity profiles, while their differential binding to fixed adherent cells agreed with expectations from expression profiles of the cells. We also introduce a proximity ligation variant of TEMA to selectively investigate binding to specific target proteins of interest. This form of the assay serves to improve resolution of binding to on- and off-target proteins. In conclusion, TEMA has the potential to aid in drug development and clinical routine by conferring valuable insights in drug–target interactions at spatial resolution in protein arrays, cells and in tissues.
16.	Al-Amin, Rasel A., 1983-, et al. (författare) Target Engagement-Mediated Amplification for Monitoring Drug-Target Interactions in Situ Annan publikation (övrigt vetenskapligt/konstnärligt)abstract It is important to determine the localization of drugs or drug candidates at cellular and subcellular resolution in relevant clinical specimens. This is necessary to evaluate drug candidates from early stages of drug development to clinical evaluation of mutations potentially causing resistance to targeted therapy. We describe a technology where oligonucleotide-conjugated drug molecules are used to visualize and measure target engagement in situ via rolling-circle amplification (RCA) of circularized oligonucleotide probes (padlock probes). We established this target engagement-mediated amplification (TEMA) technique using kinase inhibitor precursor compounds, and we applied the assay to investigate target interactions by microscopy in pathology tissue sections and using flow cytometry for blood samples from patients, as well as in commercial arrays including almost half of all human proteins. In the variant proxTEMAtechnique, in situ proximity ligation assays were performed by combining drug-DNA conjugates with antibody-DNA conjugates to specifically reveal drug binding to particular on- or off-targets in pathological tissues sections. In conclusion, the TEMA methods successfully visualize drug-target interaction by experimental and clinically approved kinase inhibitors in situ and with kinases among a large collection of arrayed proteins.
17.	Almqvist, Helena, et al. (författare) CETSA screening identifies known and novel thymidylate synthase inhibitors and slow intracellular activation of 5-fluorouracil 2016 Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7 Tidskriftsartikel (refereegranskat)abstract Target engagement is a critical factor for therapeutic efficacy. Assessment of compound binding to native target proteins in live cells is therefore highly desirable in all stages of drug discovery. We report here the first compound library screen based on biophysical measurements of intracellular target binding, exemplified by human thymidylate synthase (TS). The screen selected accurately for all the tested known drugs acting on TS. We also identified TS inhibitors with novel chemistry and marketed drugs that were not previously known to target TS, including the DNA methyltransferase inhibitor decitabine. By following the cellular uptake and enzymatic conversion of known drugs we correlated the appearance of active metabolites over time with intracellular target engagement. These data distinguished a much slower activation of 5-fluorouracil when compared with nucleoside-based drugs. The approach establishes efficient means to associate drug uptake and activation with target binding during drug discovery.
18.	Andersson, Margaretha, et al. (författare) Characterization of Surface-Modified Nanoparticles for in Vivo Biointeraction. A Sedimentation Field Flow Fractionation Study 2005 Ingår i: Analytical Chemistry. ; 77, s. 5488-5493 Tidskriftsartikel (refereegranskat)abstract Sedimentation field flow fractionation (SdFFF) is an emerging high-performance analytical tool for separation and determination of size and adsorption characteristics of colloidal particles. This study demonstrates how SdFFF can be used to characterize nanoparticles prepared for in vivo applications including (1) the quantification of polymer uptake on nanoparticles where surface coverage is crucial and (2) the coupling of cell adhesive peptides containing the Arg-Gly-Asp motif (RGD). Quantitative information about polymer adhesion in order to prepare a bioinert surface and an accurate determination of ligand uptake are both of obvious importance for the understanding of, for example, relations between the number of attached molecules for biointeraction and an observed therapeutic effect. In addition, the present work highlights the necessity to perform careful characterization of commercially available particulate starting materials, in terms of size and polydispersity, prior to biological experimentation.
19.	Andersson, Margaretha, et al. (författare) Characterization of Surface-Modified Nanoparticles for in Vivo Biointeraction. A Sedimentation Field Flow Fractionation Study 2005 Ingår i: Analytical Chemistry. ; 77, s. 5488-5493 Tidskriftsartikel (refereegranskat)
20.	Antonescu, Irina E., et al. (författare) Acamprosate Is a Substrate of the Human Organic Anion Transporter (OAT) 1 without OAT3 Inhibitory Properties : Implications for Renal Acamprosate Secretion and Drug-Drug Interactions 2020 Ingår i: Pharmaceutics. - : MDPI. - 1999-4923. ; 12:4 Tidskriftsartikel (refereegranskat)abstract Acamprosate is an anionic drug substance widely used in treating symptoms of alcohol withdrawal. It was recently shown that oral acamprosate absorption is likely due to paracellular transport. In contrast, little is known about the eliminating mechanism clearing acamprosate from the blood in the kidneys, despite the fact that studies have shown renal secretion of acamprosate. The hypothesis of the present study was therefore that renal organic anion transporters (OATs) facilitate the renal excretion of acamprosate in humans. The aim of the present study was to establish and apply OAT1 (gene product of SLC22A6) and OAT3 (gene product of SLC22A8) expressing cell lines to investigate whether acamprosate is a substrate or inhibitor of OAT1 and/or OAT3. The studies were performed in HEK293-Flp-In cells stably transfected with SLC22A6 or SLC22A8. Protein and functional data showed that the established cell lines are useful for studying OAT1- and OAT3-mediated transport in bi-laboratory studies. Acamprosate inhibited OAT1-mediated p-aminohippuric acid (PAH) uptake but did not inhibit substrate uptake via OAT3 expressing cells, neither when applied concomitantly nor after a 3 h preincubation with acamprosate. The uptake of PAH via OAT1 was inhibited in a competitive manner by acamprosate and cellular uptake studies showed that acamprosate is a substrate for OAT1 with a K-m-value of approximately 700 mu M. Probenecid inhibited OAT1-mediated acamprosate uptake with a K-i-value of approximately 13 mu M, which may translate into an estimated clinically significant DDI index. In conclusion, acamprosate was identified as a substrate of OAT1 but not OAT3.
21.	Artursson, Elisabet, et al. (författare) Catalytic-site conformational equilibrium in nerve-agent adducts of acetylcholinesterase : Possible implications for the HI-6 antidote substrate specificity 2013 Ingår i: Biochemical Pharmacology. - : Elsevier. - 0006-2952 .- 1356-1839. ; 85:9, s. 1389-1397 Tidskriftsartikel (refereegranskat)abstract Nerve agents such as tabun, cyclosarin and Russian VX inhibit the essential enzyme acetylcholinesterase (AChE) by organophosphorylating the catalytic serine residue. Nucleophiles, such as oximes, are used as antidotes as they can reactivate and restore the function of the inhibited enzyme. The oxime HI-6 shows a notably low activity on tabun adducts but can effectively reactivate adducts of cyclosarin and Russian VX. To examine the structural basis for the pronounced substrate specificity of HI-6, we determined the binary crystal structures of Mus musculus AChE (mAChE) conjugated by cyclosarin and Russian VX and found a conformational mobility of the side chains of Phe338 and His447. The interaction between HI-6 and tabun-adducts of AChE were subsequently investigated using a combination of time resolved fluorescence spectroscopy and X-ray crystallography. Our findings show that HI-6 binds to tabun inhibited Homo sapiens AChE (hAChE) with an IC50 value of 300 μM and suggest that the reactive nucleophilic moiety of HI-6 is excluded from the phosphorus atom of tabun. We propose that a conformational mobility of the side-chains of Phe338 and His447 is a common feature in nerve-agent adducts of AChE. We also suggest that the conformational mobility allow HI-6 to reactivate conjugates of cyclosarin and Russian VX while a reduced mobility in tabun conjugated AChE results in steric hindrance that prevents efficient reactivation.
22.	Artursson, Per, et al. (författare) A new opening for orally taken peptide drugs 2020 Ingår i: Nature Biomedical Engineering. - : Springer Science and Business Media LLC. - 2157-846X. ; 4:1, s. 12-13 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract Negatively charged nanoparticles of about 50 nm in size permit the oral delivery of insulin and other peptide drugs by temporally enhancing the permeability of the intestinal wall.
23.	Artursson, Per, et al. (författare) Absorption Prediction 2004 Ingår i: Profiling in Drug Discovery for Lead Selection. - : AAPS Press, Arlington VA. Bokkapitel (refereegranskat)
24.	Artursson, Per, et al. (författare) Caco-2 monolayers in experimental and theoretical predictions of drug transport 2012 Ingår i: Advanced Drug Delivery Reviews. - : Elsevier BV. - 0169-409X .- 1872-8294. ; 64:S, s. 280-289 Forskningsöversikt (refereegranskat)abstract This review examines the use of Caco-2 monolayers in the prediction of intestinal drug absorption. First, the different routes of drug transport in Caco-2 monolayers are compared with those seen in vivo. Second, the prediction of drug absorption in vivo from transport experiments in cell monolayers is discussed for different classes of drugs. Finally, the use of Caco-2 monolayers as a reference model in physico-chemical and theoretical predictions of drug absorption is discussed. We conclude that Caco-2 monolayers can be used to identify drugs with potential absorption problems, and possibly also to select drugs with optimal passive absorption characteristics from series of pharmacologically active molecules generated in drug discovery programs.
25.	Artursson, Per (författare) Experimental approaches to understand intracellular based drug bioavailability 2019 Ingår i: Drug Metabolism and Pharmacokinetics. - : JAPANESE SOC STUDY XENOBIOTICS. - 1347-4367 .- 1880-0920. ; 34:1, s. S3-S3 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
26.	Artursson, Per, et al. (författare) In vitro characterization of interactions with drug transporting proteins 2013 Ingår i: <em>Transporters in Drug Development </em>. - New York : Springer. - 9781461482284 - 9781461482291 ; , s. 37-65 Bokkapitel (refereegranskat)
27.	Artursson, Per (författare) Microspheres as drug carriers : some consequences of the delivery of microparticles to the reticuloendothelial system 1985 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)
28.	Artursson, Per (författare) New cell-based approaches for better predictions of drug transport and cellular drug exposure 2016 Ingår i: Drug metabolism reviews (Softcover ed.). - 0360-2532 .- 1097-9883. ; 48, s. 7-7 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
29.	Artursson, Tom, et al. (författare) Variable reduction on electronic tongue data 2002 Ingår i: Analytica Chimica Acta. - 0003-2670 .- 1873-4324. ; 452:2, s. 255-264 Tidskriftsartikel (refereegranskat)abstract Reduction of the number of variables in data from a so-called electronic tongue contributes to simpler model calculations and less storage requirements. In this study, we have developed a model for this purpose. This model describes the response from the electrodes in the electronic tongue with two exponential functions plus a constant term, i(t) = k + kf e-ta + kc e-tß, where t is the time. From the model, five parameters which describe the signal are extracted. These parameters can be used as inputs instead of the original signal to any multivariate algorithm. The results show that the variables obtained are at least as good as the original data to separate between different classes, even though the number of parameters has been reduced between 80 and 199 times. © 2002 Elsevier Science B.V. All rights reserved.
30.	Asad, Shno, et al. (författare) Proteomics-Informed Identification of Luminal Targets For In Situ Diagnosis of Inflammatory Bowel Disease 2021 Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 110:1, s. 239-250 Tidskriftsartikel (refereegranskat)abstract Inflammatory bowel disease (IBD) is a chronic condition resulting in impaired intestinal homeostasis. Current practices for diagnosis of IBD are challenged by invasive, demanding procedures. We hypothesized that proteomics analysis could provide a powerful tool for identifying clinical biomarkers for non-invasive IBD diagnosis. Here, the global intestinal proteomes from commonly used in vitro and in vivo models of IBD were analyzed to identify apical and luminal proteins that can be targeted by orally delivered diagnostic agents. Global proteomics analysis revealed upregulated plasma membrane proteins in intestinal segments of proximal- and distal colon from dextran sulfate sodium-treated mice and also in inflamed human intestinal Caco-2 cells pretreated with pro-inflammatory agents. The upregulated colon proteins in mice were compared to the proteome of the healthy ileum, to ensure targeting of diagnostic agents to the inflamed colon. Promising target proteins for future investigations of non-invasive diagnosis of IBD were found in both systems and included Tgm2/TGM2, Icam1/ICAM1, Ceacam1/CEACAM1, and Anxa1/ANXA1. Ultimately, these findings will guide the selection of appropriate antibodies for surface functionalization of imaging agents aimed to target inflammatory biomarkers in situ.
31.	Avdeef, Alex, et al. (författare) Caco-2 permeability of weakly basic drugs predicted with the Double-Sink PAMPA method : 2005 Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987. ; 24:4, s. 333-49 Tidskriftsartikel (refereegranskat)abstract The aim of this study was to analyze pH-dependent permeability of cationic drugs in Caco-2 cell monolayers using the method and to correlate the results with those obtained in PAMPA (parallel artificial membrane permeability assay). The pH-dependent permeability of verapamil and propranolol was studied in Caco-2 cell monolayers. The data were subsequently processed using software developed for the PAMPA method. Literature values for an additional nine cationic drugs were also analyzed. Double-Sink PAMPA data were also obtained for the same cationic drugs, to compare with the Caco-2 data. The Algorithm Builder program was then used to develop a predictive model of Caco-2 permeability based on PAMPA permeability and calculated Abraham molecular descriptors. From the relationship between permeability and pH it was shown that in PAMPA only the uncharged form of the drugs permeated across the membrane barrier, while charged and ionized forms of the drugs were significantly permeable in Caco-2. The charged-form permeability, Pi, was therefore determined and subsequently subtracted from all permeability coefficients in Caco-2 prior to the comparison with PAMPA. The resulting intrinsic permeability coefficients (Po) obtained in Caco-2 were successfully related to those derived from the PAMPA model. In this study we have shown that permeability coefficients obtained in PAMPA can predict the passive transcellular permeability in Caco-2.
32.	Avdeef, Alex, et al. (författare) Caco-2 permeability of weakly basic drugs predicted with the Double-Sink PAMPA pK flux a method. 2005 Ingår i: Eur J Pharm Sci. - 0928-0987. ; 24:4, s. 333-49 Tidskriftsartikel (refereegranskat)
33.	Beloqui, Ana, et al. (författare) A human intestinal M-cell-like model for investigating particle, antigen and microorganism translocation 2017 Ingår i: Nature Protocols. - : NATURE PUBLISHING GROUP. - 1754-2189 .- 1750-2799. ; 12:7, s. 1387-1399 Tidskriftsartikel (refereegranskat)abstract The specialized microfold cells (M cells) in the follicle-associated epithelium (FAE) of intestinal Peyer's patches serve as antigen-sampling cells of the intestinal innate immune system. Unlike 'classical' enterocytes, they are able to translocate diverse particulates without digesting them. They act as pathways for microorganism invasion and mediate food tolerance by transcellular transport of intestinal microbiota and antigens. Their ability to transcytose intact particles can be used to develop oral drug delivery and oral immunization strategies. This protocol describes a reproducible and versatile human M-cell-like in vitro model. This model can be exploited to evaluate M-cell transport of microparticles and nanoparticles for protein, drug or vaccine delivery and to study bacterial adherence and translocation across M cells. The inverted in vitro M-cell model consists of three main steps. First, Caco-2 cells are seeded at the apical side of the inserts. Second, the inserts are inverted and B lymphocytes are seeded at the basolateral side of the inserts. Third, the conversion to M cells is assessed. Although various M-cell culture systems exist, this model provides several advantages over the rest: (i) it is based on coculture with well-established differentiated human cell lines; (ii) it is reproducible under the conditions described herein; (iii) it can be easily mastered; and (iv) it does not require the isolation of primary cells or the use of animals. The protocol requires skills in cell culture and microscopy analysis. The model is obtained after 3 weeks, and transport experiments across the differentiated model can be carried out over periods of up to 10 h.
34.	Berglund, U. W., et al. (författare) Validation and development of MTH1 inhibitors for treatment of cancer 2016 Ingår i: Annals of Oncology. - : Elsevier BV. - 0923-7534 .- 1569-8041. ; 27:12, s. 2275-2283 Tidskriftsartikel (refereegranskat)abstract Background: Previously, we showed cancer cells rely on the MTH1 protein to prevent incorporation of otherwise deadly oxidised nucleotides into DNA and we developed MTH1 inhibitors which selectively kill cancer cells. Recently, several new and potent inhibitors of MTH1 were demonstrated to be non-toxic to cancer cells, challenging the utility of MTH1 inhibition as a target for cancer treatment. Material and methods: Human cancer cell lines were exposed in vitro to MTH1 inhibitors or depleted of MTH1 by siRNA or shRNA. 8-oxodG was measured by immunostaining and modified comet assay. Thermal Proteome profiling, proteomics, cellular thermal shift assays, kinase and CEREP panel were used for target engagement, mode of action and selectivity investigations of MTH1 inhibitors. Effect of MTH1 inhibition on tumour growth was explored in BRAF V600E-mutated malignant melanoma patient derived xenograft and human colon cancer SW480 and HCT116 xenograft models. Results: Here, we demonstrate that recently described MTH1 inhibitors, which fail to kill cancer cells, also fail to introduce the toxic oxidized nucleotides into DNA. We also describe a new MTH1 inhibitor TH1579, (Karonudib), an analogue of TH588, which is a potent, selective MTH1 inhibitor with good oral availability and demonstrates excellent pharmacokinetic and anti-cancer properties in vivo. Conclusion: We demonstrate that in order to kill cancer cells MTH1 inhibitors must also introduce oxidized nucleotides into DNA. Furthermore, we describe TH1579 as a best-in-class MTH1 inhibitor, which we expect to be useful in order to further validate the MTH1 inhibitor concept.
35.	Bergström, Christel A S, et al. (författare) Absorption classification of oral drugs based on molecular surface properties 2003 Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 46:4, s. 558-570 Tidskriftsartikel (refereegranskat)abstract The aim of this study was to investigate whether easily calculated and comprehended molecular surface properties can predict drug solubility and permeability with sufficient accuracy to allow theoretical absorption classification of drug molecules. For this purpose, structurally diverse, orally administered model drugs were selected from the World Health Organization (WHO)'s list of essential drugs. The solubility and permeability of the drugs were determined using well-established in vitro methods in highly accurate experimental settings. Descriptors for molecular surface area were generated from low-energy conformations obtained by conformational analysis using molecular mechanics calculations. Correlations between the calculated molecular surface area descriptors, on one hand, and solubility and permeability, on the other, were established with multivariate data analysis (partial least squares projection to latent structures (PLS)) using training and test sets. The obtained models were challenged with external test sets. Both solubility and permeability of the druglike molecules could be predicted with high accuracy from the calculated molecular surface properties alone. The established correlations were used to perform a theoretical biopharmaceutical classification of the WHO-listed drugs into six classes, resulting in a correct prediction for 87% of the essential drugs. An external test set consisting of Food and Drug Administration (FDA) standard compounds for biopharmaceutical classification was predicted with 77% accuracy. We conclude that PLS models of easily comprehended molecular surface properties can be used to rapidly provide absorption profiles of druglike molecules early on in drug discovery.
36.	Bergström, Christel A S, et al. (författare) Accuracy of calculated pH-dependent aqueous drug solubility. 2004 Ingår i: European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987. ; 22:5, s. 387-98 Tidskriftsartikel (refereegranskat)abstract The aim of the present study was to investigate the extent to which the Henderson-Hasselbalch (HH) relationship can be used to predict the pH-dependent aqueous solubility of cationic drugs. The pH-dependent solubility for 25 amines, carrying a single positive charge, was determined with a small-scale shake flask method. Each sample was prepared as a suspension in 150 mM phosphate buffer. The pH-dependent solubility curves were obtained using at least 10 different pH values. The intrinsic solubility, the solubility at the pKa and the solubility at pH values reflecting the pH of the bulk and acid microclimate in the human small intestine (pH 7.4 and 6.5, respectively) were determined for all compounds. The experimental study revealed a large diversity in slope, from -0.5 (celiprolol) to -8.6 (hydralazine) in the linear pH-dependent solubility interval, which is in sharp contrast to the slope of -1 assumed by the HH equation. In addition, a large variation in the range of solubility between the completely uncharged and completely charged drug species was observed. The range for disopyramide was only 1.1 log units, whereas that for amiodarone was greater than 6.3 log units, pointing at the compound specific response to counter-ion effects. In conclusion, the investigated cationic drugs displayed compound specific pH-dependent solubility profiles, indicating that that the HH equation in many cases will only give rough estimations of the pH-dependent solubility of drugs in divalent buffer systems.
37.	Bergström, Christel A. S., et al. (författare) Accuracy of calculated pH-dependent aqueous drug solubility Tidskriftsartikel (refereegranskat)
38.	Bergström, Christel A. S., 1973- (författare) Computational and Experimental Models for the Prediction of Intestinal Drug Solubility and Absorption 2003 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract New effective experimental techniques in medicinal chemistry and pharmacology have resulted in a vast increase in the number of pharmacologically interesting compounds. However, the number of new drugs undergoing clinical trial has not augmented at the same pace, which in part has been attributed to poor absorption of the compounds.The main objective of this thesis was to investigate whether computer-based models devised from calculated molecular descriptors can be used to predict aqueous drug solubility, an important property influencing the absorption process. For this purpose, both experimental and computational studies were performed. A new small-scale shake flask method for experimental solubility determination of crystalline compounds was devised. This method was used to experimentally determine solubility values used for the computational model development and to investigate the pH-dependent solubility of drugs. In the computer-based studies, rapidly calculated molecular descriptors were used to predict aqueous solubility and the melting point, a solid state characteristic of importance for the solubility. To predict the absorption process, drug permeability across the intestinal epithelium was also modeled.The results show that high quality solubility data of crystalline compounds can be obtained by the small-scale shake flask method in a microtiter plate format. The experimentally determined pH-dependent solubility profiles deviated largely from the profiles predicted by a traditionally used relationship, highlighting the risk of data extrapolation. The in silico solubility models identified the non-polar surface area and partitioned total surface areas as potential new molecular descriptors for solubility. General solubility models of high accuracy were obtained when combining the surface area descriptors with descriptors for electron distribution, connectivity, flexibility and polarity. The used descriptors proved to be related to the solvation of the molecule rather than to solid state properties. The surface area descriptors were also valid for permeability predictions, and the use of the solubility and permeability models in concert resulted in an excellent theoretical absorption classification. To summarize, the experimental and computational models devised in this thesis are improved absorption screening tools applicable to the lead optimization in the drug discovery process.
39.	Bergström, Christel A. S., et al. (författare) Early pharmaceutical profiling to predict oral drug absorption : Current status and unmet needs 2014 Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 57, s. 173-199 Tidskriftsartikel (refereegranskat)abstract Preformulation measurements are used to estimate the fraction absorbed in vivo for orally administered compounds and thereby allow an early evaluation of the need for enabling formulations. As part of the Oral Biopharmaceutical Tools (OrBiTo) project, this review provides a summary of the pharmaceutical profiling methods available, with focus on in silica and in vitro models typically used to forecast active pharmaceutical ingredient's (APIs) in vivo performance after oral administration. An overview of the composition of human, animal and simulated gastrointestinal (GI) fluids is provided and state-of-the art methodologies to study API properties impacting on oral absorption are reviewed. Assays performed during early development, i.e. physicochemical characterization, dissolution profiles under physiological conditions, permeability assays and the impact of excipients on these properties are discussed in detail and future demands on pharmaceutical profiling are identified. It is expected that innovative computational and experimental methods that better describe molecular processes involved in vivo during dissolution and absorption of APIs will be developed in the OrBiTo. These methods will provide early insights into successful pathways (medicinal chemistry or formulation strategy) and are anticipated to increase the number of new APIs with good oral absorption being discovered. (C) 2013 Elsevier B.V. All rights reserved.
40.	Bergström, Christel A. S., et al. (författare) Experimental and computational screening models for prediction of aqueous drug solubility 2002 Ingår i: Pharmaceutical Research. ; 19, s. 182- Tidskriftsartikel (refereegranskat)
41.	Bergström, Christel A S, et al. (författare) Global and local computational models for aqueous solubility prediction of drug-like molecules. 2004 Ingår i: Journal of chemical information and computer sciences. - : American Chemical Society (ACS). - 0095-2338 .- 1520-5142. ; 44:4, s. 1477-88 Tidskriftsartikel (refereegranskat)abstract The aim of this study was to develop in silico protocols for the prediction of aqueous drug solubility. For this purpose, high quality solubility data of 85 drug-like compounds covering the total drug-like space as identified with the ChemGPS methodology were used. Two-dimensional molecular descriptors describing electron distribution, lipophilicity, flexibility, and size were calculated by Molconn-Z and Selma. Global minimum energy conformers were obtained by Monte Carlo simulations in MacroModel and three-dimensional descriptors of molecular surface area properties were calculated by Marea. PLS models were obtained by use of training and test sets. Both a global drug solubility model (R(2) = 0.80, RMSE(te) = 0.83) and subset specific models (after dividing the 85 compounds into acids, bases, ampholytes, and nonproteolytes) were generated. Furthermore, the final models were successful in predicting the solubility values of external test sets taken from the literature. The results showed that homologous series and subsets can be predicted with high accuracy from easily comprehensible models, whereas consensus modeling might be needed to predict the aqueous drug solubility of datasets with large structural diversity.
42.	Bergström, Christel A.S., et al. (författare) Global and Local Computational Models for Aqueous Solubility Prediction of Drug-Like Molecules 2004 Ingår i: Journal of Chemical Information and Computer Sciences. ; 44:4, s. 1477-1488 Tidskriftsartikel (refereegranskat)
43.	Bergström, Christel A. S., et al. (författare) Global and local computational models for aqueous solubility prediction of drug-like molecules Tidskriftsartikel (refereegranskat)
44.	Bergström, Christel A S, et al. (författare) Hepatitis C virus NS3 protease inhibitors : large, flexible molecules of peptide origin show satisfactory permeability across Caco-2 cells 2009 Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 38:5, s. 556-563 Tidskriftsartikel (refereegranskat)abstract The purpose of this study was to investigate the intestinal absorption of tripeptide-based compounds intended for treatment of hepatitis C virus (HCV) infection. The intestinal permeability of 11 HCV NS3 protease inhibitors (Mw 687-841, ClogD(pH 7.4) 1.2-7.3 and 10-13 hydrogen bond donors/acceptors) was measured using Caco-2 cells. Each compound was investigated in the apical to basolateral (a-b) and basolateral to apical (b-a) direction at pH 7.4. For compounds displaying efflux the experiment was repeated in the presence of 1 microM GF120918 to investigate possible involvement of P-glycoprotein (Pgp; ABCB1). All compounds displayed intermediate to high permeability. Seven of them showed extensive efflux, with 31-114-fold higher permeability in the b-a direction than the a-b direction. Addition of the Pgp inhibitor GF120918 reduced the b-a transport rate for the effluxed compounds. However, for inhibitors with a C-terminal carboxylic acid and the acidic bioisosteres thereof the efflux was still significant. Hence, the negative charge resulted in efflux by other ABC-transporters than Pgp. From this study it can be concluded that small changes in the overall structure can lead to a large variation in permeability and efflux as shown by the inhibitors herein, properties that also may influence the resulting inhibition potency of the compounds when performing cell-based pharmacological assays.
45.	Bergström, Christel A. S., et al. (författare) Molecular descriptors influencing melting point and their role in classification of solid drugs 2003 Ingår i: Journal of Chemical Information and Computer Sciences. ; 43:4, s. 1177-1185 Tidskriftsartikel (refereegranskat)
46.	Bäckström, Gunilla, et al. (författare) Genetic variation in the ATP-binding cassette transporter gene ABCG2(BCRP) in a Swedish population 2003 Ingår i: European Journal of Pharmaceutical Sciences. - 0928-0987 .- 1879-0720. ; 18:5, s. 359-364 Tidskriftsartikel (refereegranskat)abstract The ATP-binding cassette transporter ABCG2 (also named breast cancer resistance protein, BCRP) functions as a drug efflux transporter and is expressed at high levels in the human small intestine. The aim of this study was to screen the human ABCG2 gene for genetic variation. The regions of the gene most likely to affect function, namely the coding parts, exon/intron boundaries, 5' untranslated region and 3' untranslated region and the proposed promoter region, were included in the screening. DNA was obtained from 60 Swedish individuals. The screening was performed using a polymerase chain reaction-denaturing high-performance liquid chromatography approach followed by sequence analysis. Eight sites of genetic variation were identified. The sequence variations considered to be most likely to affect transcription level or transport function were a CTCA deletion in the 5' flanking region, a single nucleotide polymorphism (SNP) in a 5' flanking CpG island, two non-synonymous SNPs, changing valine at amino acid position 12 to methionine and glutamine at position 141 to lysine, respectively. Genotyping of these sequence variations revealed linkage between the CTCA deletion and the SNP changing glutamine 141 for lysine. This information forms the basis for future association studies to investigate the genetic basis of differences of drug disposition due to sequence variation in the ABCG2 gene.
47.	Chen, Eugene C., et al. (författare) High Throughput Screening of a Prescription Drug Library for Inhibitors of Organic Cation Transporter 3, OCT3 2022 Ingår i: Pharmaceutical research. - : Springer. - 0724-8741 .- 1573-904X. ; 39:7, s. 1599-1613 Tidskriftsartikel (refereegranskat)abstract Introduction The organic cation transporter 3 (OCT3, SLC22A3) is ubiquitously expressed and interacts with a wide array of compounds including endogenous molecules, environmental toxins and prescription drugs. Understudied as a determinant of pharmacokinetics and pharmacodynamics, OCT3 has the potential to be a major determinant of drug absorption and disposition and to be a target for drug-drug interactions (DDIs).Goal The goal of the current study was to identify prescription drug inhibitors of OCT3.Methods We screened a compound library consisting of 2556 prescription drugs, bioactive molecules, and natural products using a high throughput assay in HEK-293 cells stably expressing OCT3.Results We identified 210 compounds that at 20 mu M inhibit 50% or more of OCT3-mediated uptake of 4-Di-1-ASP (2 mu M). Of these, nine were predicted to inhibit the transporter at clinically relevant unbound plasma concentrations. A Structure-Activity Relationship (SAR) model included molecular descriptors that could discriminate between inhibitors and non-inhibitors of OCT3 and was used to identify additional OCT3 inhibitors. Proteomics of human brain microvessels (BMVs) indicated that OCT3 is the highest expressed OCT in the human blood-brain barrier (BBB).Conclusions This study represents the largest screen to identify prescription drug inhibitors of OCT3. Several are sufficiently potent to inhibit the transporter at therapeutic unbound plasma levels, potentially leading to DDIs or off-target pharmacologic effects.
48.	de Waal, Tom, et al. (författare) Expression of intestinal drug transporter proteins and metabolic enzymes in neonatal and pediatric patients 2024 Ingår i: International Journal of Pharmaceutics. - : Elsevier. - 0378-5173 .- 1873-3476. ; 654 Tidskriftsartikel (refereegranskat)abstract The development of pediatric oral drugs is hampered by a lack of predictive simulation tools. These tools, in turn, require data on the physiological variables that influence oral drug absorption, including the expression of drug transporter proteins (DTPs) and drug-metabolizing enzymes (DMEs) in the intestinal tract. The expression of hepatic DTPs and DMEs shows age-related changes, but there are few data on protein levels in the intestine of children. In this study, tissue was collected from different regions of the small and large intestine from neonates (i.e., surgically removed tissue) and from pediatric patients (i.e., gastroscopic duodenal biopsies). The protein expression of clinically relevant DTPs and DMEs was determined using a targeted mass spectrometry approach. The regional distribution of DTPs and DMEs was similar to adults. Most DTPs, with the exception of MRP3, MCT1, and OCT3, and all DMEs showed the highest protein expression in the proximal small intestine. Several proteins (i.e., P-gp, ASBT, CYP3A4, CYP3A5, CYP2C9, CYP2C19, and UGT1A1) showed an increase with age. Such increase appeared to be even more pronounced for DMEs. This exploratory study highlights the developmental changes in DTPs and DMEs in the intestinal tract of the pediatric population. Additional evaluation of protein function in this population would elucidate the implications of the presented changes in protein expression on absorption of orally administered drugs in neonates and pediatric patients.
49.	de Waal, Tom, et al. (författare) The impact of inflammation on the expression of drug transporters and metabolic enzymes in colonic tissue from ulcerative colitis patients 2022 Ingår i: International Journal of Pharmaceutics. - : Elsevier. - 0378-5173 .- 1873-3476. ; 628 Tidskriftsartikel (refereegranskat)abstract The intestinal tract forms an important barrier against xenobiotics while allowing nutrients to pass. In ulcerative colitis (UC), a chronic inflammatory bowel disease, this barrier function is impaired leading to an abnormal immune response and inflammation of the colonic mucosa. Transporter proteins and metabolic enzymes are an integral part of the protective barrier in the gut and play an important role in the disposition of nutrients, toxins and oral drugs. In this study, the protein expression of 13 transporters and 13 enzymes was determined in the sigmoid and rectum of UC patients in endoscopic remission and during active inflammation. In inflamed con-ditions (endoscopic Mayo sub-score 1, 2 or 3), a significant decrease (q < 0.05) was observed in the median expression of the transporters P-gp (0.046 vs 0.529 fmol/mu g protein), MRP4 (0.003 vs 0.023 fmol/mu g protein) and MCT1 (0.287 vs 1.090 fmol/mu g protein), and the enzymes CYP3A5 (0.031 vs 0.046 fmol/mu g protein) and UGT2B7 (0.083 vs 0.176 fmol/mu g protein). Moreover, during severe inflammation, the decrease was even more pro-nounced. Expression levels of other proteins were not altered during inflammation (e.g., OATP2B1, CYP3A4, CYP2B6 and UGT2B15). The results suggest a decreased transport and metabolism of xenobiotics in the colon of UC patients during active inflammation potentially altering local drug concentrations and thus treatment outcome.
50.	des Rieux, Anne, et al. (författare) Influence of nanoparticle properties on their transport across an in vitro model of the human intestinal follicle associated epithelium 2005 Ingår i: European Journal of Pharmaceutical Sciences. - 0928-0987. ; 25, s. 455-465 Tidskriftsartikel (refereegranskat)

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