Altered pH(i) regulation in 3T3/CFTR clones and their chemotherapeutic drug-selected derivatives Journal Article

Authors: Wei, L. Y.; Huffman, M. M.; Roepe, P. D.
Article Title: Altered pH(i) regulation in 3T3/CFTR clones and their chemotherapeutic drug-selected derivatives
Abstract: 3T3 cells overexpressing the cystic fibrosis transmembrane conductance regulator (CFTR) were found to exhibit chemotherapeutic drug resistance and other traits of multidrug resistant (MDR) cells. In the present work, NIH 3T3/CFTR clones were selected with either doxorubicin or vincristine in incremental fashion to generate series of stable MDR cell lines that exhibit increasing levels of drug resistance. Thus C3D6 (grown in the presence of 600 nM doxorubicin) was selected from C3D4 (grown in the presence of 400 nM doxorubicin), which was selected from C3D1 (grown in the presence of 100 nM doxorubicin), which was in turn selected from the original 3T3/CFTR clone C3 (M. J. Stutts, S. E. Gabriel, J. C. Olsen, J. T. Gatzy, T. L. O'Connell, E. M. Price, and R. C. Boucher. J. Biol. Chem. 268: 20653-20658, 1993), which was not grown in the presence of chemotherapeutic drug. A similar series was generated via selection with vincristine. In both series, as well as series derived from a different CFTR clone, initial low-level drug selection increases CFTR expression without promoting MDR 1 or multidrug resistance- associated protein expression. On continued selection at higher drug concentrations, CFTR mRNA levels decrease while MDR 1 mRNA levels concomitantly increase. At each incremental step of selection, intracellular pH (pH(i)) increases (e.g., pH(i) of C3D6 > C3D4 > C3D1 > C3). Cl/HCO3/- exchange activity is significantly reduced in the drug-selected derivatives overexpressing MDR 1 but not the parental CFTR clones. The apparent set point of Na+/H+ exchange activity is significantly lower for the non-drug- selected 3T3/CFTR clones, relative to controls, but it increases on initial selection with chemotherapeutic drug. Overexpression of MDR-1 in the higher- level selectants does not appear to further perturb apparent Na+/H+ exchange. These data further describe how CFTR and MDR proteins may affect pH(i) regulation.
Keywords: controlled study; genetics; doxorubicin; nonhuman; animal cell; mouse; animal; metabolism; animals; mice; gene expression; cell line; ph; vincristine; drug effect; physiology; animalia; messenger rna; rna, messenger; transmembrane conductance regulator; abc transporter; cell clone; blotting, northern; clone cells; cell strain 3t3; multidrug resistance; hydrogen-ion concentration; p-glycoprotein; 3t3 cells; colchicine; drug resistance, multiple; proton; northern blotting; antiporter; hydrogen; glycoprotein p; intracellular membranes; bicarbonate; chloride ion; sodium ion; ion transport; cystic fibrosis transmembrane conductance regulator; sodium-hydrogen antiporter; cell ph; cell membrane potential; intracellular membrane; priority journal; article; antiporters; sodium proton exchange protein; anion exchanger; sodium-hydrogen exchanger; bicarbonate chloride antiporter; ion exchange; chloride-bicarbonate antiporters
Journal Title: American Journal of Physiology - Cell Physiology
Volume: 272
Issue: 5
ISSN: 0363-6143
Publisher: American Physiological Society  
Date Published: 1997-05-01
Start Page: C1642
End Page: C1653
Language: English
PUBMED: 9176156
PROVIDER: scopus
Notes: Article -- Export Date: 17 March 2017 -- Source: Scopus
Citation Impact
MSK Authors
  1. Paul D. Roepe
    26 Roepe