Fluorescent dyes as functional probes for studying drug-transporting solute carriers

Area of Science:

• Pharmacology
• Biochemistry
• Drug Development

Background:

• Solute carrier (SLC) transporters significantly influence drug pharmacokinetics and are implicated in drug-drug interactions.
• Regulatory evaluation of new molecular entities necessitates understanding their interactions with SLCs.
• Fluorescent probes have emerged as tools for studying SLCs, with various substrates characterized for this purpose.

Purpose of the Study:

• To review the application of fluorescent probes for in vitro investigation of interactions between xenobiotics and key SLC transporters.
• To discuss the advantages and limitations of fluorescent probe-based assays for SLC studies.
• To highlight the utility of these assays in pharmaceutical development and regulatory science.

Main Methods:

• Review of existing literature on fluorescent probes and their use in SLC transporter assays.
• Discussion of cis-inhibition, trans-stimulation, and competitive counterflow assay principles.
• Comparison of fluorescent probe assays with conventional methods like radiolabeled substrates and LC-MS/MS.

Main Results:

• Fluorescent probe assays enable characterization of xenobiotic inhibition of SLC activity (cis-inhibition).
• These assays facilitate studies on SLC fundamental properties, polymorphisms, regulatory pathways, and substrate identification (trans-stimulation/competitive counterflow).
• Dye-based assays are more cost-effective, less labor-intensive, and compatible with high-throughput screening compared to traditional methods.

Conclusions:

• Fluorescent probe-based assays are valuable, cost-effective tools for studying SLC transporters in drug development.
• While offering advantages, limitations such as probe specificity and assay performance for substrate identification need consideration.
• These assays aid in evaluating drug interactions and characterizing xenobiotic effects on SLCs for regulatory purposes.