Selection of a new multidrug resistant cell line from Friend leukemia cells by short and cyclic exposures to high concentrations of daunorubicin.
BACKGROUND
Resistance of tumor cells to cytotoxic agents can be due to the overexpression of the mdr 1 gene, which encodes a plasma membrane protein (P-glycoprotein). To understand the molecular basis of multidrug resistance, several laboratories have isolated cell lines resistant to doxorubicin, actinomycin D, vinca alkaloids and related agents. Many months or years of culture with gradually increasing concentrations of cytotoxic agents are necessary to obtain a resistant cell line.


METHODS
We selected a new multidrug resistant cell line (MELC-DRTL) by 24-hour cycles of exposure to relatively high concentrations of daunorubicin from sensitive Friend Leukemia cells. After each cycle, the residual live cells were expanded up to the density of 1 x 10(6) cells/ml.


RESULTS
The assay conducted with MoAb C-219 showed a high expression on the membrane surface of P-glycoprotein in the MELC-DRTL line, but the fact that it was impossible to obtain a complete reversal of the resistance, even when using high concentrations of verapamil, suggests the presence of other mechanisms unrelated to the presence of P-glycoprotein.


CONCLUSIONS
The kind of cellular resistance induction used in this experiment enabled us to obtain an MDR cell line in three months of culture.
Cattedra di Ematologia, Università di Palermo, Italy.
V
V
Abbadessa
M
M
Tolomeo
M
M
Luparello
R
R
Perricone
A
A
Cajozzo
L
L
Dusonchet
V
V
Candiloro
L
L
Crosta
L
L
Rausa
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000818:Animals; D003630:Daunorubicin / Q000494:pharmacology*; D004351:Drug Resistance; D005434:Flow Cytometry; D005622:Friend murine leukemia virus; D004915:Leukemia, Erythroblastic, Acute / Q000473:pathology*; D008562:Membrane Glycoproteins / Q000032:analysis / Q000037:antagonists & inhibitors; D008565:Membrane Proteins / Q000032:analysis; D051379:Mice; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000473:pathology
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D003630:Daunorubicin