AJP - Cell Physiology, Vol 263, Issue 1 C176-C186, Copyright © 1992 by American Physiological Society
Altered sulfate transport via anion exchange in CFPAC is corrected by retrovirus-mediated CFTR gene transfer
A. Elgavish and E. Meezan
Department of Comparative Medicine, University of Alabama, Birmingham School of Medicine 35294.
PANC-1 (a permanent epithelioid cell line initiated from a pancreatic
carcinoma of ductal origin) and CFPAC (a ductal epithelioid cell line
established from a cystic fibrosis patient with pancreatic adenocarcinoma)
display sulfate transport via carrier-mediated anion exchange as supported
by the following lines of evidence: 1) saturation kinetics, 2) inhibition
by the anion exchange inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic
acid (DIDS), and 3) substrate specificity. The DIDS-sensitive component of
sulfate uptake is markedly inhibited by S2O3(2-) and MoO4(2-) but not by
HAsO4(2-), H2PO4-, or gluconate-. Competitive inhibition of SO4(2-) uptake
by extracellular Cl- (Cl-o) and stimulation of SO4(2-) efflux by Cl-o
support the possibility that SO4(2-) transport occurs via a SO4(2-)-Cl-
exchange mechanism. Inhibition of sulfate uptake and stimulation of sulfate
efflux by extracellular HCO3- indicate that SO4(2-)-HCO3- exchange is an
alternative mechanism for sulfate transport in these cells. Further support
for SO4(2-) being transported via a typical anion exchanger is the
stimulation of its uptake at low extracellular pH and high intracellular
pH. Amphotropic viruses have been used by others (M. L. Drumm, H. A. Pope,
W. H. Cliff, J. M. Rommens, S. A. Marvin, L.-C. Tsui, F. S. Collins, R. A.
Frizzell, and J. M. Wilson. Cell 62: 1227-1233, 1990) to transduce a
functional cystic fibrosis transmembrane regulator (CFTR) cDNA into CFPAC,
resulting in the PLJ-CFTR clones. Control clones (PLJ) were obtained by
exposing CFPAC cells to control virus. In the present study, we report a
striking 10-fold increase in the capacity of the DIDS-sensitive component
of the sulfate transporter in two PLJ-CFTR clones (which had been shown by
others to express corrected Cl- channel activity) compared with CFPAC and
two PLJ clones. Our findings indicate that expression of the CFTR gene from
a retroviral vector, which confers normal Cl- channel activity in the
PLJ-CFTR pancreas epithelial clones, is capable of correcting a second
aspect of the cystic fibrosis phenotype, altered sulfate transport via an
anion exchange mechanism.
