TY - JOUR
T1 - A novel cDNA restores reduced folate carrier activity and methotrexate sensitivity to transport deficient cells
AU - Dixon, Katharine H.
AU - Lanpher, Brendan C.
AU - Chiu, Jason
AU - Kelley, Kristin
AU - Cowan, Kenneth H.
N1 - Copyright:
Copyright 2005 Elsevier B.V., All rights reserved.
PY - 1994/1/7
Y1 - 1994/1/7
N2 - Mammalian cells accumulate reduced folates and methotrexate, a folate antagonist, through the reduced-folate carrier (RFC) (Goldman, I. D., Lichtenstein, N. S., and Oliverio, V. T. (1968) J. Biol. Chem. 243, 5007- 5017). This study describes the isolation and expression of a cDNA clone that restores RFC activity to human breast cancer cells defective in this transporter. The cDNA codes for a peptide (mRFC1) of 58 kDa, whose hydropathy plot, resembling those of mammalian sugar transporters, predicts that it may be a member of a superfamily of transporter genes. Transfection of methotrexate-resistant (MTX(R)) ZR-75-1 cells with an expression vector, pRFC1, that codes for this peptide restores their ability to accumulate methotrexate. Furthermore, transport of methotrexate into pRFC1-transfected cells is blocked by a 10-fold molar excess of the reduced folate, 5- formyltetrahydrofolic acid, but is unaffected by folic acid. The increase in methotrexate uptake that is observed in pRFC1-transfected MTX(R) ZR-75-1 cells reverses their resistance to this antitumor agent.
AB - Mammalian cells accumulate reduced folates and methotrexate, a folate antagonist, through the reduced-folate carrier (RFC) (Goldman, I. D., Lichtenstein, N. S., and Oliverio, V. T. (1968) J. Biol. Chem. 243, 5007- 5017). This study describes the isolation and expression of a cDNA clone that restores RFC activity to human breast cancer cells defective in this transporter. The cDNA codes for a peptide (mRFC1) of 58 kDa, whose hydropathy plot, resembling those of mammalian sugar transporters, predicts that it may be a member of a superfamily of transporter genes. Transfection of methotrexate-resistant (MTX(R)) ZR-75-1 cells with an expression vector, pRFC1, that codes for this peptide restores their ability to accumulate methotrexate. Furthermore, transport of methotrexate into pRFC1-transfected cells is blocked by a 10-fold molar excess of the reduced folate, 5- formyltetrahydrofolic acid, but is unaffected by folic acid. The increase in methotrexate uptake that is observed in pRFC1-transfected MTX(R) ZR-75-1 cells reverses their resistance to this antitumor agent.
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M3 - Article
C2 - 8276792
AN - SCOPUS:0027982786
SN - 0021-9258
VL - 269
SP - 17
EP - 20
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 1
ER -