Generation of a Human Conditionally Immortalized Cell-based Multicellular Spheroidal Blood-Brain Barrier Model for Permeability Evaluation of Macromolecules.

There is an urgent need for the development of brain drug delivery carriers based on middle-sized or macromolecules, to which blood-brain barrier (BBB) models are expected to contribute significantly through evaluation of BBB permeability. As part of efforts to develop such models, we have been working on human conditionally immortalized cell-based multicellular spheroidal BBB models (hiMCS-BBB models), and we herein introduce the model development protocol. Briefly, astrocytes are first seeded in an ultra-low attachment 3D cell culture plate, to make the central core (Day 0).

Human Immortalized Cell-Based Blood-Brain Barrier Spheroid Models Offer an Evaluation Tool for the Brain Penetration Properties of Macromolecules.

Blood-brain barrier (BBB)-permeable middle- or macromolecules (middle/macromolecules) have recently attracted significant attention as new drug delivery carriers into the human brain via receptor-mediated transcytosis (RMT). During the development process of such carriers, it is necessary to thoroughly evaluate their human BBB permeability levels. In such evaluations, our recently established human immortalized cell-based multicellular spheroidal BBB models (hiMCS-BBB models) have shown high potential.

In Vitro-In Vivo Correlation of Blood-Brain Barrier Permeability of Drugs: A Feasibility Study Towards Development of Prediction Methods for Brain Drug Concentration in Humans.

Purpose: In vitro human blood-brain barrier (BBB) models in combination with central nervous system-physiologically based pharmacokinetic (CNS-PBPK) modeling, hereafter referred to as the "BBB/PBPK" method, are expected to contribute to prediction of brain drug concentration profiles in humans. As part of our ongoing effort to develop a BBB/PBPK method, we tried to clarify the relationship of in vivo BBB permeability data to those in vitro obtained from a human immortalized cell-based tri-culture BBB model (hiBBB), which we have recently created.

Methods: The hiBBB models were developed and functionally characterized as previously described.

Effects of islatravir (4'-ethynyl-2-fluoro-2'-deoxyadenosine or EFdA) on renal tubular cells and islatravir's interactions with organic anion transporters.

Islatravir (ISL; 4'-ethynyl-2-fluoro-2'-deoxyadenosine or EFdA) is a novel reverse transcriptase translocation inhibitor and has a unique structure and high antiviral activity against wild-type and multidrug resistant HIV strains. In this study, we investigated whether islatravir (ISL) can cause kidney damage compared to tenofovir disoproxil fumarate (TDF) and tenofovir (TFV). We also investigated interactions of these drugs with organic anion transporters (OATs).

Development, Characterization and Potential Applications of a Multicellular Spheroidal Human Blood-Brain Barrier Model Integrating Three Conditionally Immortalized Cell Lines.

In vitro blood-brain barrier (BBB) models are essential research tools for use in developing brain-targeted drugs and understanding the physiological and pathophysiological functions of the BBB. To develop BBB models with better functionalities, three-dimensional (3D) culture methods have gained significant attention as a promising approach. In this study, we report on the development of a human conditionally immortalized cell-based multicellular spheroidal BBB (hiMCS-BBB) model.

Protein kinase C activation upregulates human L-type amino acid transporter 2 function.

L-type amino acid transporter 2 (LAT2) is a Na-independent neutral amino acid transporter, whose function regulation system remains unclarified. Since protein kinase C (PKC) is known to regulate the functions of various transporters, we investigated whether human LAT2 (hLAT2) function is regulated by PKC. In mouse proximal tubule S2 cells, hLAT2 transport activity was upregulated by PKC activation.

JPH203, a newly developed anti-cancer drug, shows a preincubation inhibitory effect on L-type amino acid transporter 1 function.

JPH203 is a novel anti-cancer drug targeting L-type amino acid transporter 1 (LAT1), which plays a primary role in the uptake of essential amino acids in tumor cells. Although a co-incubation inhibitory effect of JPH203 has been shown in a conventional uptake assay, its preincubation inhibitory effects have remained undetermined. Therefore, we aimed to characterize the preincubation inhibitory effects of JPH203 on LAT1 function using leucine uptake assays in LAT1-positive human colon cancer HT-29 cells.

Different Response Profiles of Gastrointestinal Cancer Cells to an L-Type Amino Acid Transporter Inhibitor, JPH203.

Background/aim: L-type amino acid transporter 1 (LAT1) is a promising molecular target for cancer therapy. The present study aimed to characterize the anti-cancer effects of JPH203, an LAT1-selective inhibitor, on gastrointestinal cancer cells.

Materials And Methods: Three esophageal, two gastric, and two colon cancer cell lines were used.

Synthesis of novel benzbromarone derivatives designed to avoid metabolic activation.

We synthesized six novel BBR derivatives that were designed to avoid metabolic activation via ipso-substitution and evaluated for their degree of toxicity and hURAT1 inhibition. It was found that all of the derivatives demonstrate lower cytotoxicity in mouse hepatocytes and lower levels of metabolic activation than BBR, while maintaining their inhibitory activity toward the uric acid transporter. We propose that these derivatives could serve as effective uricosuric agents that have much better safety profiles than BBR.

Differentiated HASTR/ci35 cells: A promising in vitro human astrocyte model for facilitating CNS drug development studies.

Astrocytes have shown longstanding promise as therapeutic targets for various central nervous system diseases. To facilitate drug development targeting astrocytes, we have recently developed a new conditionally immortalized human astrocyte cell line, termed HASTR/ci35 cells. In this study, in order to further increase their chances to contribute to various astrocyte studies, we report on the development of a culture method that improves HASTR/ci35 cell differentiation status and provide several proofs related to their astrocyte characteristics.

Cancer-Type OATP1B3 mRNA in Extracellular Vesicles as a Promising Candidate for a Serum-Based Colorectal Cancer Biomarker.

Cancer-type organic anion transporting polypeptide 1B3 (Ct-OATP1B3) mRNA is a variant isoform of the liver-type OATP1B3. Because Ct-OATP1B3 mRNA shows an excellent cancer-specific expression profile in colorectal cancer (CRC), and that its expression levels are associated with CRC prognosis, it holds the potential to become a useful CRC detection and diagnosis biomarker. While the potential is currently justified only at the tissue level, if existence of Ct-OATP1B3 mRNA in CRC-derived extracellular vesicles (EVs) is validated, the findings could enhance its translational potential as a CRC detection and diagnosis biomarker.

Development of a New Conditionally Immortalized Human Liver Sinusoidal Endothelial Cells.

Liver sinusoidal endothelial cells (LSECs), which are specialized endothelial cells that line liver sinusoids, have been reported to participate in a variety of liver functions, such as blood macromolecule clearance and factor VIII production. In addition, LSECs play crucial roles in liver regeneration following acute liver injury, as well as the development and progression of liver diseases or drug-induced hepatotoxicity. However, the molecular mechanisms underlying their roles remain mostly unknown.

Human organic anion transporter 2 is an entecavir, but not tenofovir, transporter.

Entecavir (ETV) and tenofovir (TFV) are essential nucleoside analogues in current hepatitis B virus (HBV) treatments. Since these drugs target the HBV polymerase that is localized within human hepatocytes, determining of their cellular uptake process is an important step in fully understanding their pharmacological actions. However, the human hepatic transporters responsible for their uptake have remained unidentified.

Differential inhibition features of direct-acting anti-hepatitis C virus agents against human organic anion transporting polypeptide 2B1.

Simeprevir (SMV), asunaprevir (ASV), daclatasvir (DCV) and sofosbuvir (SOF), which are direct-acting antiviral (DAA) agents, are expected to become essential pharmaceutical tools in the fight against the hepatitis C virus (HCV). However, because DAAs are taken orally, there is a potential risk of drug-drug interactions (DDIs) at the absorption step with co-administered drugs in the small intestine. Since it is known that organic anion transporting polypeptide 2B1 (OATP2B1) is one of the key transporters contributing to intestinal drug absorption, it is important to thoroughly understand the inhibition profiles of various DAAs in relation to OATP2B1 function in order to avoid unexpected DDIs.