Establishment of two new multi-drug resistant variants of the human tumor line Hep-2

Abstract

Two multi-drug resistant variants of the human carcinoma line Hep-2 have been selected by adaptation to progressively increasing concentrations of adriamycin. In comparison to the wild-type Hep-2 cells, the variant lines both showed approximately 100-fold resistance to adriamycin, 10 to 20-fold resistance to the vinca alkaloids but only 2-3 fold resistance to VP-16 and VM-26. There was essentially no difference between wild-type and variant cells in regard to sensitivity to threosulfan and 5-fluorouracil. The drug-resistant phenotype is stable for at least 3 months in the absence of drug, and is partially reversible by concomitant treatment with Verapamil. Chromosomal abnormalities consistent with gene amplification were observed in one of the variant lines. Sensitivity of variant cells to adriamycin was enhanced following trypsin-EDTA treatment.

Analysis of the mechanism of resistance of 7 novel MDR variants

“…Indirect imnunofluorescence was preformed on 8 well slides (Nunc) ; cells were grown on the slides for 24 hours and then fixed in ice cold acetone for 10 minutes, prior to incubation with C219 antibody (Centocor Diagnostics, U.S.A.). Northern blotting procedures were preformed according to the procedure of Chirgwin et d. [6] using pCHPI probe for recognition of the 4.8k.b MDRl transcript. A direct role for the evaluation of the role of P-170 was studied by the transfection of sense and antisense oligomers, using an 18 mar which encodes for 18 bases down stream of the MDRl promoter.…”