MicroRNA profiling in K-562 cells under imatinib treatment: influence of miR-212 and miR-328 on ABCG2 expression.

Background: Despite the enormous success of imatinib in chronic myeloid leukemia (CML), therapy resistance has emerged in a significant proportion of patients, partly because of the overexpression of ABC efflux transporters.

Methods: Using an array comprising 667 miRNAs, we investigated whether the expression of microRNAs (miRNAs) is altered in CML K-562 cells becoming resistant to increasing concentrations of imatinib. ABCB1 and ABCG2 mRNA (quantitative real-time PCR) and protein expression (western blot) were quantified under short-term and 4 months' imatinib treatment.

Down-regulation of ATP-binding cassette C2 protein expression in HepG2 cells after rifampicin treatment is mediated by microRNA-379.

microRNAs (miRNAs), which contribute to the post-transcriptional processing through 3'-untranslated region-interference, have been shown to be involved in the regulation of ATP-binding cassette (ABC) membrane transporters. The aim of this study was to investigate whether ABCC2, an important efflux transporter for various endogenous and exogenous compounds at several compartment barriers, is subject to miRNA-mediated post-transcriptional gene regulation. We screened the expression of 377 human miRNAs in HepG2 cells after 48 h of treatment with 5 μM rifampicin [a pregnane X receptor (PXR) ligand] or vehicle using reverse transcription-polymerase chain reaction-based low-density arrays.