Expression and localization of efflux drug transporters P-glycoprotein and breast cancer resistance protein (BCRP) in adult human pancreatic islet alpha and beta cells

P-glycoprotein (P-gp, ABCB1) and breast cancer resistance protein (BCRP, ABCG2) are clinically important efflux transporters of the ATP-binding cassette (ABC) family of transporters, widely recognized for their broad substrate specificity associated with multidrug resistance in cancers and limiting substrate drug intracellular accumulation. While their expression and function in organs such as the intestine, liver and kidneys are well understood, there is little known concerning pancreatic islet cells. This study was aimed to characterize the expression and localization of P-gp and BCRP transporters in adult human pancreatic islets using quantitative reverse transcription PCR (qPCR) and dual immunofluorescent staining approaches. We showed that P-gp and BCRP were highly expressed in the islets compared to liver, and frequently colocalized with insulin or glucagon. These findings provide new insights regarding P-gp and BCRP abundance in beta and alpha cells suggesting a potential role for these efflux transporters in limiting islet cell injury to xenobiotics.