title: Combination of active and inactive siRNA targeting the mitotic kinesin Eg5 impairs silencing efficiency in several cancer cell lines.
abstract: Gene silencing by RNA interference (RNAi) has proven to be a powerful tool for investigating gene function in mammalian cells. Combination of several short interfering RNA (siRNA) targeting the same gene is commonly used to improve RNA interference. However, in contrary to the well-described mechanism of RNAi, efficiency of single siRNA compared to pool remains poorly documented. We addressed this issue using several active and inactive siRNA targeting Eg5, a kinesin-related motor involved in mitotic spindle assembly. These siRNA, used alone or in combination, were tested for their silencing efficiency in several cancer cell lines. Here we show that presence of inactive Eg5 siRNA in a pool dramatically decreases knockdown efficacy in a cell line- and dose-dependent manner. Lack of inhibition by unrelated siRNA suggests that a competition may occur during siRNA incorporation into RNA-induced silencing complexes (RISCs) along with the target mRNA. Altogether, our results, which need to be confirmed with additional inactive siRNA, indicate that combination of siRNA may not increase but instead decrease silencing efficiency.
authors.affiliation: Hybrigenics SA, 75014 Paris, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Formstecher
authors.forename: Celine
authors.initials: C
authors.lastname: Reverdy
authors.forename: Mickael
authors.initials: M
authors.lastname: Cholay
authors.forename: Cecile
authors.initials: C
authors.lastname: Planquette
authors.forename: Virginie
authors.initials: V
authors.lastname: Trouplin
authors.forename: Heike
authors.initials: H
authors.lastname: Lehrmann
authors.forename: Sandra
authors.initials: S
authors.lastname: Aresta
authors.forename: Alessandra
authors.initials: A
authors.lastname: Calabrese
authors.forename: Khalil
authors.initials: K
authors.lastname: Arar
authors.forename: Laurent
authors.initials: L
authors.lastname: Daviet
authors.forename: Frederic
authors.initials: F
authors.lastname: Colland
mesh_terms: D001483:Base Sequence; D045744:Cell Line, Tumor; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D016547:Kinesins / Q000037:antagonists & inhibitors* / Q000235:genetics*; D008938:Mitosis / Q000187:drug effects / Q000235:genetics; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology*; D014162:Transfection
chemical_list: D018076:DNA, Complementary; C470243:KIF11 protein, human; D034741:RNA, Small Interfering; D016547:Kinesins