Analysis of Protein Digestion and Absorption Using a Ussing Chamber to Simulate the Environment in the Digestive Tract.

The Ussing chamber is a tool for analyzing drug absorption. We investigated whether the Ussing chamber can be used to analyze the process from digestion to absorption of protein in the gastrointestinal tract. Mixtures containing infant formula, whole cow's milk, processed soy milk, enteral nutrition, or human breast milk, were placed in the apical membrane side equipped with Caco-2 cells.

Clinical Analysis and in Vitro Correlation of BCRP-Mediated Drug-Drug Interaction in the Gastrointestinal Tract.

Breast cancer resistance protein (BCRP) is a drug efflux transporter expressed on the epithelial cells of the small intestine and on the lateral membrane of the bile duct in the liver; and is involved in the efflux of substrate drugs into the gastrointestinal lumen and secretion into bile. Recently, the area under the plasma concentration-time curve (AUC) of rosuvastatin (ROS), a BCRP substrate drug, has been reported to be increased by BCRP inhibitors, and BCRP-mediated drug-drug interaction (DDI) has attracted attention. In this study, we performed a ROS uptake study using human colon cancer-derived Caco-2 cells and confirmed that BCRP inhibitors significantly increased the intracellular accumulation of ROS.

Mechanism of Induction of P-gp Activity During MET Induced by DEX in Lung Cancer Cell Line.

Lung cancer metastasis often leads to a poor prognosis for patients. Mesenchymal-epithelial transition (MET) is one key process associated with metastasis. MET has also been linked to multidrug drug resistance (MDR).

Novel Screening System for Biliary Excretion of Drugs Using Human Cholangiocyte Organoid Monolayers with Directional Drug Transport.

It has recently been reported that cholangiocyte organoids can be established from primary human hepatocytes. The purpose of this study was to culture the organoids in monolayers on inserts to investigate the biliary excretory capacity of drugs. Cholangiocyte organoids prepared from hepatocytes had significantly higher mRNA expression of CK19, a bile duct epithelial marker, compared to hepatocytes.

Pharmacokinetics of Biopharmaceuticals: Their Critical Role in Molecular Design.

Biopharmaceuticals have developed rapidly in recent years due to the remarkable progress in gene recombination and cell culture technologies. Since the basic structure of biopharmaceuticals can be designed and modified, it is possible to control the duration of action and target specific tissues and cells by kinetic modification. Amino acid sequence modifications, albumin fusion proteins, polyethylene glycol (PEG) modifications, and fatty acid modifications have been utilized to modify the duration of action control and targeting.

Transporter and metabolic enzyme-mediated intra-enteric circulation of SN-38, an active metabolite of irinotecan: A new concept.

SN-38, an active metabolite of irinotecan (CPT-11), is thought to circulate enterohepatically via organic anion-transporting polypeptides (OATPs), UDP-glucuronyl transferases (UGTs), multidrug resistance-related protein 2 (MRP2), and breast cancer resistance protein (BCRP). These transporters and enzymes are expressed in not only hepatocytes but also enterocytes. Therefore, we hypothesized that SN-38 circulates between the intestinal lumen and the enterocytes via these transporters and metabolic enzymes.

P-Glycoprotein-Mediated Pharmacokinetic Interactions Increase Pimozide hERG Channel Inhibition.

Pimozide, an antipsychotic drug, is a potent inhibitor of the hERG channel. A case of death due to cardiac arrest has been reported in a boy who received pimozide together with sertraline and aripiprazole. In this study, we focused on drug-drug interactions and investigated the relationships between transporter-mediated intracellular accumulation and the hERG inhibitory effect of pimozide.

Slug Mediates MRP2 Expression in Non-Small Cell Lung Cancer Cells.

Transcriptional factors, such as Snail, Slug, and Smuc, that cause epithelial-mesenchymal transition are thought to regulate the expression of Ezrin, Radixin, and Moesin (ERM proteins), which serve as anchors for efflux transporters on the plasma membrane surface. Our previous results using lung cancer clinical samples indicated a correlation between Slug and efflux transporter MRP2. In the current study, we aimed to evaluate the relationships between MRP2, ERM proteins, and Slug in lung cancer cells.

Directional Drug Transport through Membrane-Supported Monolayers of Human Liver-Derived Cell Lines.

The aim of this work is to develop a new assay system for screening biliary excretion drugs. When monolayers of human liver-derived cell lines HepG2 and Huh-7 were grown on an insert membrane, the efflux ratio (ER: ratio of the apparent permeability coefficient in the basal-to-apical direction (P) to that in the apical to basal direction (P)) of sulfobromophthalein (BSP), a model substrate of multidrug resistance-associated protein 2 (MRP2), was greater than 1.0, indicating transport of BSP in the efflux direction.

Correlations of mRNA Levels among Efflux Transporters, Transcriptional Regulators, and Scaffold Proteins in Non-Small-Cell Lung Cancer.

Multidrug resistance (MDR) due to enhanced drug efflux activity of tumor cells can severely impact the efficacy of antitumor therapies. We recently showed that increased activity of the efflux transporter P-glycoprotein (P-gp) associated with activation of Snail transcriptional regulators may be mediated mainly by moesin in lung cancer cells. Here, we aimed to systematically evaluate the relationships among mRNA expression levels of efflux transporters (P-gp, breast cancer resistance protein (BCRP), and multidrug resistance-associated protein 2 (MRP2)), scaffold proteins (ezrin (Ezr), radixin (Rdx), and moesin (Msn); ERM proteins), and SNAI family members (Snail, Slug, and Smac) in clinical lung cancer and noncancer samples.

Imaging modalities for monitoring acute therapeutic effects after near-infrared photoimmunotherapy in vivo.

Near-infrared photoimmunotherapy (NIR-PIT) induces immediate cell death after irradiation with near-infrared (NIR) light. Acute therapeutic effects caused by NIR-PIT before the change of tumor size is essential to be monitored by imaging modalities. We summarized and compared the imaging modalities for evaluating acute therapeutic effects after NIR-PIT, and aimed to provide a better understanding of advantages and disadvantages of each modality for evaluation in clinical applications.

Effect of metformin on F-fluorodeoxyglucose uptake and positron emission tomographic imaging.

Metformin is widely used to treat diabetes, but induces changes in glucose uptake in both normal organs and tumors. Here, we review the effects of metformin on the uptake of F-fludeoxyglucose (F-FDG) in tissues and tumors, and its influence on F-FDG positron emission tomographic imaging (F-FDG PET), as well as the mechanisms involved. This is an important issue, because metformin has diverse effects on tissue uptake of F-FDG, and this can affect the quality and interpretation of PET images.

Evaluation system for cell-permeable CYP3A4 inhibitory activity using 1α,25-dihydroxy-vitamin D-induced intestinal cell lines.

We developed an assay system to evaluate the cytochrome P450 (CYP) 3A4-inhibitory activity of compounds, taking account of their cellular permeability, using intestine-derived cell lines pre-treated with the CYP3A4 inducer 1α,25-dihydroxy-vitamin D (250 nM).Ketoconazole (KTZ), saquinavir (SQV), naringin, naringenin (NGE), bergamottin (BG), 6',7'-dihydroxybergamottin (DHBG), epigallocatechin gallate (EGCG), and resveratrol (RES) were evaluated as known CYP3A4 inhibitors. The apparent IC (IC) values of known inhibitors were determined in Caco-2 cells with 10 µM midazolam as a CYP3A4 substrate, and compared with the IC values in a human liver microsome assay.

Physiological Roles of ERM Proteins and Transcriptional Regulators in Supporting Membrane Expression of Efflux Transporters as Factors of Drug Resistance in Cancer.

One factor contributing to the malignancy of cancer cells is the acquisition of drug resistance during chemotherapy via increased expression of efflux transporters, such as P-glycoprotein (P-gp), multidrug resistance-associated proteins (MRPs), and breast cancer resistance protein (BCRP). These transporters operate at the cell membrane, and are anchored in place by the scaffold proteins ezrin (Ezr), radixin (Rdx), and moesin (Msn) (ERM proteins), which regulate their functional activity. The identity of the regulatory scaffold protein(s) differs depending upon the transporter, and also upon the tissue in which it is expressed, even for the same transporter.

Gastrointestinal absorption of pimozide is enhanced by inhibition of P-glycoprotein.

Drug-drug interaction was suggested to have played a role in the recent death due to cardiac arrest of a patient taking pimozide, sertraline and aripiprazole antipsychotic/antidepressant combination therapy. Here, we investigated the possible involvement of P-glycoprotein (P-gp)-mediated interaction among these drugs, using in vitro methods. ATPase assay confirmed that pimozide is a P-gp substrate, and might act as a P-gp inhibitor at higher concentrations.

Utility of Three-Dimensional Cultures of Primary Human Hepatocytes (Spheroids) as Pharmacokinetic Models.

This paper reviews the usefulness, current status, and potential of primary human hepatocytes (PHHs) in three-dimensional (3D) cultures, also known as spheroids, in the field of pharmacokinetics (PK). Predicting PK and toxicity means pharmaceutical research can be conducted more efficiently. Various in vitro test systems using human hepatocytes have been proposed as tools to detect hepatic toxicity at an early stage in the drug development process.

Establishment of a primary human hepatocyte spheroid system for evaluating metabolic toxicity using dacarbazine under conditions of CYP1A2 induction.

Some drugs induce cytochrome P450s (CYPs), and thus may cause increased metabolic toxicity from concomitantly administered agents. Hence, we need a means of evaluating the potential of compounds to cause drug-induced liver injury (DILI) under conditions where inducers of CYP1A2 are present. Here, we present a system for evaluating CYP1A2-mediated metabolic toxicity using three-dimensional (3D) cultures of primary human hepatocyte spheroids treated with the CYP1A2 inducer omeprazole (OPZ).

Indole-3-propionic acid has chemical chaperone activity and suppresses endoplasmic reticulum stress-induced neuronal cell death.

Insoluble aggregated proteins are often associated with neurodegenerative diseases. Previously, we investigated chemical chaperones that prevent the aggregation of denatured proteins. Among these, 4-phenyl butyric acid (4-PBA) has well-documented chemical chaperone activity, but is required at doses that have multiple effects on cells, warranting further optimization of treatment regimens.

Structure-activity relationship of atorvastatin derivatives for metabolic activation by hydrolases.

1. We investigated the structure-activity relationship of 31 kinds of synthesized atorvastatin esters, thioesters, amides and lactone, selected as prodrug models, for metabolic activation by microsomes and hydrolases.2.

Synthesis and evaluation of atorvastatin esters as prodrugs metabolically activated by human carboxylesterases.

We synthesized 11 kinds of prodrug with an esterified carboxylic acid moiety of atorvastatin in moderate to high yields. We discovered that they underwent metabolic activation specifically by the human carboxylesterase 1 (CES1) isozyme. The results suggested that these ester compounds of atorvastatin have the potential to act as prodrugs in vivo.

A new methodology for functionalization at the 3-position of indoles by a combination of boron Lewis acid with nitriles.

We discovered that a reagent comprising a combination of PhBCl2 and nitriles was useful for syntheses of both 3-acylindoles and 1-(1H-indol-3-yl)alkylamine from indoles. The reaction proceeded selectively at the 3-position of indoles providing 3-acylindoles in moderate to high yields on treatment with the above reagent. Furthermore, the reaction provided the corresponding amine products in moderate to high yields after the intermediate imine was reduced by NaBH3CN.