Vincristine transcriptional regulation of efflux drug transporters in carcinoma cell lines.
The increased expression of drug transporters following cancer chemotherapy contributes to resistance. This may reflect transcriptional up-regulation and/or clonal selection. We quantified the expression of mRNA for ABCB1 (mdr1), ABCC1 (mrp1), ABCC2 (mrp2) and ABCC3 (mrp3) to evaluate the potential contribution of induction. ABCB1, ABCC1-3 mRNAs were quantified by real time RT-PCR and normalized to GAPDH. We used intestinal cells that express high pregnane X receptor (LS174T), low pregnane X receptor (Caco-2) and lung cells (A549) that express glucocorticoid receptor and low pregnane X receptor. Rifampin (10 microM) caused significant induction of ABCB1 (595+/-263%, p<0.05) in LS174T cells but induction was absent in Caco-2 or A549 cells. ABCC1 was not induced in any cell at 24, 48 and 72 h following rifampin treatment. In contrast, vincristine (10 nM and 100 nM), a ligand for ABCB1 and ABCC1-3 and a potential PXR/CAR ligand, induced ABCC2 and ABCC3 expression in LS174T cells at 48 h (372+/-87% and 303+/-42%, respectively, p<0.05). A similar induction of ABCC2 and ABCC3 genes was also seen with 10 nM VCR in A549 cells following 48 h treatment. In summary, there may be a significant contribution of transcriptional activation to multi-drug resistance. However, this is cell selective and is not necessarily dependent on PXR mediated effects.
Huang
Rong
R
Department of Pharmacy Practice, School of Pharmacy and Pharmaceutical Sciences, Purdue University, Indianapolis, IN 46202, USA.
Murry
Daryl J
DJ
Kolwankar
Dhanashri
D
Hall
Stephen D
SD
Foster
David R
DR
D001483:Base Sequence; D045744:Cell Line, Tumor; D017931:DNA Primers; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics* / Q000378:metabolism; D000077297:Pregnane X Receptor; D012333:RNA, Messenger / Q000235:genetics; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics; D011987:Receptors, Steroid / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects*; D014750:Vincristine / Q000494:pharmacology*
D017931:DNA Primers; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D000077297:Pregnane X Receptor; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D014750:Vincristine; C000715087:ABCC2 protein, human