Multidrug resistance phenotype of human BRO melanoma cells transfected with a wild-type human mdr1 complementary DNA.
We have transfected a eukaryotic expression vector containing a mdr1 complementary DNA isolated from normal human liver into human BRO melanoma cells to study the drug-resistant phenotype produced by the exclusive overexpression of normal human mdr1 P-glycoprotein. The drug resistance pattern of mdr1-transfected clones includes relatively high resistance to gramicidin D (about 300-fold), vincristine (about 100-fold), and actinomycin D (about 100-fold) and a lower degree of resistance to doxorubicin (about 10-fold), VP16-213 (about 10-fold), and colchicine (about 6-fold). The transfectants did not exhibit resistance to trimetrexate, cis-platinum, mitomycin C, 1-beta-D-arabinofuranosylcytosine, bleomycin, G418, or magainin-2-amide; they were slightly more sensitive to verapamil (2-fold) but not to Triton X-100. As in other multidrug-resistant cell lines, resistance to vincristine could be reversed by verapamil and, more effectively, by cyclosporin A. Chloroquine only marginally increased drug sensitivity in mdr1-transfected cells. Gramicidin D resistance was also reversed by verapamil, suggesting that the mechanism of resistance to this polypeptide antibiotic is similar to that of other drugs transported by P-glycoprotein. Thus, expression of the wild-type mdr1 complementary DNA induces a drug-resistant phenotype similar to that induced by mdr1 complementary DNAs isolated from drug-resistant cell lines with relatively low colchicine resistance. As other cell lines may display a different pattern of drug resistance, it is clear that other resistance mechanisms or cell type-specific factors may modulate the resistance. mdr1-transfected cell lines provide a convenient tool for the identification of P-glycoprotein-mediated phenomena.
Lincke
C R
CR
Division of Molecular Biology, The Netherlands Cancer Institute, Amsterdam.
van der Bliek
A M
AM
Schuurhuis
G J
GJ
van der Velde-Koerts
T
T
Smit
J J
JJ
Borst
P
P
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001692:Biological Transport; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004247:DNA / Q000235:genetics; D003630:Daunorubicin / Q000378:metabolism; D004351:Drug Resistance / Q000235:genetics*; D006801:Humans; D007700:Kinetics; D008545:Melanoma; D008562:Membrane Glycoproteins / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D010641:Phenotype; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D008562:Membrane Glycoproteins; D004247:DNA; D003630:Daunorubicin