Oliver Bruhn1, Katharina Drerup1, Meike Kaehler1, Sierk Haenisch1, Christian Röder2, Ingolf Cascorbi1. 1. Institute of Experimental & Clinical Pharmacology, University Hospital Schleswig-Holstein, Campus Kiel, Germany. 2. Division of Molecular Oncology, Institute for Experimental Cancer Research, University Hospital Schleswig-Holstein, Campus Kiel, Germany.
Abstract
AIM: To identify the exact length and possible length variations of the ABCB1 3'-UTR as important regulatory site for miRNA interaction of this drug transporter and its possible contribution to drug resistance. MATERIALS & METHODS: 3'-RACE and various standard PCR experiments were performed using cDNA of different human cell lines and liver tissue. The abundance of 3'-UTR fragments was analyzed using quantitative RT-PCR. RESULTS: Five different ABCB1 3'-UTR length variants were identified. miRNA binding sites were located only on the three longer fragments. Imatinib-resistant leukemia cells expressed predominantly shorter 3'-UTRs, where miRNA binding sites are absent. CONCLUSION: Shortening of the ABCB1 3'-UTR causes loss of miRNA-dependent translational control leading to elevated ABCB1 protein levels.
AIM: To identify the exact length and possible length variations of the ABCB1 3'-UTR as important regulatory site for miRNA interaction of this drug transporter and its possible contribution to drug resistance. MATERIALS & METHODS: 3'-RACE and various standard PCR experiments were performed using cDNA of different human cell lines and liver tissue. The abundance of 3'-UTR fragments was analyzed using quantitative RT-PCR. RESULTS: Five different ABCB1 3'-UTR length variants were identified. miRNA binding sites were located only on the three longer fragments. Imatinib-resistant leukemia cells expressed predominantly shorter 3'-UTRs, where miRNA binding sites are absent. CONCLUSION: Shortening of the ABCB1 3'-UTR causes loss of miRNA-dependent translational control leading to elevated ABCB1 protein levels.
Entities:
Keywords:
MDR1; P-glycoprotein; drug resistance; miRNA; polyadenylation; post-transcriptional regulation