The effects of intralaboratory modifications to media composition and cell source on the expression of pharmaceutically relevant transporters and metabolizing genes in the Caco-2 cell line.

Expression and function of drug transporters and drug-metabolizing enzymes (DMEs) in the gastrointestinal tract are critical attributes of intestinal physiology that influence the absorption of orally administered compounds. The purpose of this study was to examine the effects of media composition and cell source on mRNA expression and function of pharmaceutically relevant drug transporters and DMEs from two different sources of Caco-2 cells. Briefly, cells were cultured in either minimum essential medium alpha or Dulbecco's modified Eagle's medium. Total RNA was isolated from each experimental group, and mRNA expression was evaluated using quantitative reverse-transcriptase polymerase chain reaction arrays. Principal component analysis was used to analyze results, which indicated variable transporter and metabolic expression attributable to differences in media composition and cell source. In addition, transport properties of paracellular markers and proton-dependent oligopeptide transporter-mediated substrates across Caco-2 cell monolayers were assessed. Transport experiments demonstrated significant differences in both paracellular and transcellular permeation resultant from differences in media composition and cell source. These studies support previous findings that media composition and cell source may significantly impact expressional and functional characteristics of Caco-2 cells. Standardization of culture-related methodology may reduce variability associated with Caco-2 cells, enabling more meaningful intralaboratory and interlaboratory data comparisons.