Genetic polymorphisms in SLCO2B1 and ABCC1 conjointly modulate atorvastatin intracellular accumulation in HEK293 recombinant cell lines

Background: Although Atorvastatin (ATV), is generally well tolerated, patients can experience muscle complaints. The occurrence of this discomfort is difficult to predict owing to high inter-individual variability. Muscle side effects are thought to be linked to intramuscular accumulation of ATV. The present study aimed at investigating the relative implication of influx and efflux transporters expressed in the muscle tissue (OATP2B1 and MRP1) in promoting or limiting the access of the drug into the cells. In addition, the impact of common single nucleotide polymorphisms (SNPs) in SLCO2B1 coding for OATP2B1 (rs12422149; c.935G>A) and ABCC1 coding for MRP1 (rs45511401; c.2012G>T) towards ATV transport was evaluated. Methods: HEK293 cells were stably transfected with plasmids containing full-length cDNA coding for the wild-type or the variant SLCO2B1 and/or ABCC1 to generate single and double stable transfectant HEK293 recombinant models overexpressing variant or wild-type OATP2B1 (influx) and/or MRP1 (efflux) proteins. Variant plasmids were generated using site directed mutagenesis. Expression analyses were performed through fluorescent microscopy and flow cytometry to validate the recombinant models. Accumulation and efflux experiments were carried out at different concentrations. ATV was quantified by LC-MS/MS and kinetic parameters were then compared between single and double HEK-transfectant expressing the wild-type and variant proteins. Results: Our results confirm the involvement of OATP2B1 and MRP1 in ATV cellular transport as we showed that intracellular accumulation of ATV was boosted by OATP2B1 overexpression whereas ATV accumulation was decreased by MRP1 overexpression. In double-transfectants, it was observed that the increased ATV intracellular accumulation driven by OATP2B1 influx was partially counteracted by MRP1 efflux. Finally, the c.935G>A SNP in SLCO2B1 was associated with decreased ATV OATP2B1-mediated influx whereas the c.2012G>T SNP in ABCC1 appeared to increase MRP1 efflux activity towards ATV.