title: Expression levels of human P-glycoprotein in in vitro cell lines: correlation between mRNA and protein levels for P-glycoprotein expressed in cells.
abstract: The purpose of this study was to investigate the correlation between mRNA and protein levels for P-glycoprotein (P-gp) expressed in various cell lines to validate the estimation of P-gp activity from its mRNA levels. P-gp expression levels in various cell monolayers, normal, P-gp-induced, P-gp-highly induced, (multidrug resistance, MDR) MDR1-knockdown (A2-2) and MDR1-knockdown (B2-2) Caco-2 cells and MDCKII/MDR1 cells, were quantified by real-time quantitative polymerase chain reaction (PCR) and western blot analysis. Both mRNA and protein levels of P-gp were lowest in the MDR1-knockdown (B2-2) Caco-2 cells, followed by the MDR1-knockdown (A2-2) Caco-2, normal Caco-2, P-gp-induced Caco-2 and P-gp-highly induced Caco-2 cells, and highest in the MDCKII/MDR1 cells. Except for the MDCKII/MDR1 cells, the protein levels of P-gp in all Caco-2 cell lines showed a linear correlation with its mRNA levels; however, although the MDR1 mRNA level in MDCKII/MDR1 cells was much higher than in the P-gp-highly induced Caco-2 cells, the protein levels were almost the same in both cells. From these findings, it was suggested that P-gp activity in MDCKII/MDR1 cells could not be estimated from its mRNA levels.
authors.affiliation: Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Osaka, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Shirasaka
authors.forename: Reiko
authors.initials: R
authors.lastname: Konishi
authors.forename: Nana
authors.initials: N
authors.lastname: Funami
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kadowaki
authors.forename: Yuri
authors.initials: Y
authors.lastname: Nagai
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Sakaeda
authors.forename: Shinji
authors.initials: S
authors.lastname: Yamashita
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D018938:Caco-2 Cells; D004285:Dogs; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014747:Vinblastine / Q000494:pharmacology
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014747:Vinblastine