c-Ha-ras transfection and expression of MDR-related genes in MCF-10A human breast cell line.
BACKGROUND
We studied the relationship between ras transfection and the drug resistance phenotype in the MCF-10A cell line (a non-transformed immortalized human breast epithelial cell line).


METHODS
Parental (MCF-10A) and c-Ha-ras transfected (MCF-10A H) cell lines were tested for resistance to Doxorubicin, Maphosphamide and Cisplatinum, by evaluating the inhibition of [3H]-thymidine incorporation. Cells were also examined for the expression of different resistance mechanisms by immunocytochemical and RT-PCR methods.


RESULTS
ras-transfected cells were much more resistant to Cis-platinum than parental ones. GST-pi the GST isoenzyme frequently involved in human cancers) increased only in transfected cells. No expression of any other resistance mechanisms (MDR, MRP, LRP) was found by immunocytochemistry either in parental or in transfected cells; nevertheless, the more sensitive RT-PCR tests detected mrp products in parental and in transfected cells: gene expression levels were low and equivalent in both cell lines.


CONCLUSIONS
ras transfection can induce resistance to Cis-platinum by increasing GST-pi expression.
Di Simone
D
D
Oncology Department, University of Pisa, Italy.
Galimberti
S
S
Basolo
F
F
Ciardiello
F
F
Petrini
M
M
Scheper
R J
RJ
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics*; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D019450:Genes, MDR; D011905:Genes, ras; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*; D014162:Transfection; D014407:Tumor Cells, Cultured; D020394:Vault Ribonucleoprotein Particles; D000099187:Major Vault Protein
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018528:ATP-Binding Cassette Transporters; D005982:Glutathione Transferase; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins; D016283:Proto-Oncogene Proteins p21(ras); D020394:Vault Ribonucleoprotein Particles; D000099187:Major Vault Protein; C501009:HRAS protein, human