P31.02
Background: Drug transporters expressed in the cervicovaginal (CV) epithelium are likely to influence delivery of antiretroviral (ARV)-vaginal microbicides to subepithelial target cells for HIV-1. This study aims to characterise drug transporters in CV cell lines and investigate the impact of dapivirine (DPV) and darunavir (DRV) on gene expression for development of in vitro assays for testing transport of candidate ARV-microbicides across the CV epithelium.
Methods: Expression of 84 human drug transporter genes was investigated in HEC1A, End1E6E7, Ect1E6E7 and VK2E6E7 using RT-qPCR. The impact of DPV and DRV on HEC1A and VK2E6E7 drug transporters expression was analysed over 72 hours.
Results: End1E6E7, Ect1E6E7 and VK2E6E7 cell lines showed similar baseline expression profiles distinct from HEC-1A. ARV-associated uptake transporters ENT1, ENT2, OATPD, and OATPE were expressed in all cell lines. OATP8 was expressed in HEC1A only, and CNT3 expressed in all but HEC1A. Expression of ARV-efflux transporters P-gp and BCRP was low across all cell lines. Upon stimulation of HEC-1A with DPV (10uM) upregulation of efflux transporters MRP2, MRP5 and downregulation of uptake transporters OATP8, OATPE was observed. VK2E6E7 stimulation with DPV showed downregulation of OATPE and CNT3. DRV (250uM) induced expression in HEC-1A of MRP2, MRP5, MRP7 and P-gp. VK2E6E7 stimulation with DRV resulted in upregulation of OATPD, CNT3, MRP3 and MRP5 and downregulation of MRP4, MRP7 and OATPE. All reported expression changes following ARV stimulation were>2 fold.
Conclusions: In the absence of ARVs the cell lines investigated express uptake transporters reported in CV tissue, but minimal levels of ARV-efflux transporters P-gp and BCRP. Cell lines transfected to overexpress P-gp and BCRP may be suitable for use in transport studies. The downregulation of uptake transporters and upregulation of efflux transporters induced by both ARVs, seen in HEC1A, may suggest reduced drug delivery to subepithelial target cells in the CV tract.
