title: P21 gene knock down does not identify genetic effectors seen with gene knock out.
abstract: RNA interference (RNAi) has become a popular tool for analyzing gene function in cancer research. The feasibility of using RNAi in cellular and animal models as an alternative to conventional gene knock out approaches has been demonstrated. Although these studies show that RNAi can recapitulate phenotypes seen in knock out animals and their derived cell lines, a systematic study rigorously comparing downstream effector genes between RNAi and gene knock out has not been performed. Here we present data contrasting the phenotypic and genotypic changes that occur with either stable knock down via RNAi of the cyclin dependent kinase inhibitor p21 versus its somatic cell knock out counterpart in the human mammary epithelial cell line MCF-10A. Our results demonstrate that p21 knock down clones display a growth proliferative response upon exposure to Transforming Growth Factor-Beta Type 1 (TGFbeta) similar to p21 knock out clones. However, gene expression profiles were significantly different in p21 knock down cells versus p21 knock out clones. Importantly p21 knock down clones did not display increased gene expression of interleukin-1alpha (IL-1alpha), a critical effector of this growth response previously validated in p21 knock out cells. We conclude that gene knock out can yield additional vital information that may be missed with gene knock down strategies.
authors.affiliation: The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Bedri
authors.initials: B
authors.lastname: Karakas
authors.forename: Ashani T
authors.initials: AT
authors.lastname: Weeraratna
authors.forename: Abde M
authors.initials: AM
authors.lastname: Abukhdeir
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Konishi
authors.forename: John P
authors.initials: JP
authors.lastname: Gustin
authors.forename: Michele I
authors.initials: MI
authors.lastname: Vitolo
authors.forename: Kurtis E
authors.initials: KE
authors.lastname: Bachman
authors.forename: Ben Ho
authors.initials: BH
authors.lastname: Park
mesh_terms: D045744:Cell Line, Tumor; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000037:antagonists & inhibitors* / Q000235:genetics*; D006801:Humans; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D034741:RNA, Small Interfering; D016212:Transforming Growth Factor beta