title: The reduction of P-glycoprotein expression by small interfering RNAs is improved in exponentially growing cells.
abstract: Small interfering RNAs (siRNAs) are powerful tools in specifically silencing gene expression. Nevertheless, their efficiency can be limited when targeting proteins with an unusually long half-life, such as P-glycoprotein (P-gp), which is involved in the multidrug resistance phenomenon. P-gp is characterized by a long half-life, which may vary depending on the cell line and, for some of them, on serum deprivation or high cell density. In the present paper, involvement of an exponential cell growth phase in the improvement of siRNA efficiency has been suggested. The doxorubicin-selected human line MCF7-R was shown to be a more adapted model than NIH-MDR-G185 cells stably transfected with human mdr1. Nonspecific effects occurring at moderate (100 nM) siRNA concentration have been shown. Two efficient siRNAs led to a very satisfactory P-gp extinction (only 20% P-gp expression remaining) with siRNA concentration as low as 20 nM.
authors.affiliation: Laboratoire de Physicochimie Biomoléculaire et Cellulaire, CNRS (UMR 7033) and Université P. et M. Curie, 75005 Paris, France.
authors.forename: Vérène
authors.initials: V
authors.lastname: Stierlé
authors.forename: Alain
authors.initials: A
authors.lastname: Laigle
authors.forename: Béatrice
authors.initials: B
authors.lastname: Jollès
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000818:Animals; D018432:Drug Resistance, Multiple; D015870:Gene Expression / Q000187:drug effects / Q000235:genetics; D019450:Genes, MDR; D006801:Humans; D051379:Mice; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D034741:RNA, Small Interfering