Cytokines alter the expression and activity of the multidrug resistance transporters in human hepatoma cell lines; analysis using RT-PCR and cDNA microarrays.
Pro-inflammatory cytokines suppress the hepatic expression of the multidrug resistance transporters in rodents, indicating potential usefulness in chemotherapy. Our objective was to investigate their impact in human hepatoma cells. HuH 7 and HepG2 cells were treated with IL-1beta, IL-6, or TNF-alpha for 0-72 h. Expression and activity of MDR1 and the MRP (MRP1, 2, 3, and 6) transporters were examined by RT-PCR, efflux assays, and microarrays. Significant reductions in the MDR1-mediated efflux of Rhodamine 123 and MDR1 mRNA levels were observed in HuH 7 cells treated with IL-6, TNF-alpha, or IL-1beta and in TNF-alpha-treated HepG2 cells. However, cytokine-treated HuH7 cells also demonstrated 1.6- to 2.6-fold greater efflux of the MRP substrate, 5-carboxyfluorescein (5-CF) and higher MRP3 mRNA levels (p < 0.05). IL-1beta and IL-6 treatments increased MRP activity and MRP1 mRNA levels in HepG2 cells (p < 0.05). Microarrays studies performed in IL-6 and TNF-alpha-treated HepG2 cells detected similar changes in the expression of the MDR1 and MRP transporters, but this did not reach significance. However, the microarrays confirmed cytokine-mediated induction of several acute phase proteins. Our data suggests that although cytokine-mediated suppression of PGP may alter drug resistance in malignant cells, these cytokines may also impose an induction in other multidrug resistance genes.
Lee
Gigi
G
Faculty of Pharmacy, University of Toronto, 19 Russell Street, Toronto, Ontario, Canada M5S 2S2.
Piquette-Miller
Micheline
M
D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000494:pharmacology*; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D005456:Fluorescent Dyes; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020112:Rhodamine 123
D016207:Cytokines; D018076:DNA, Complementary; D005456:Fluorescent Dyes; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012313:RNA; D011994:Recombinant Proteins; D020112:Rhodamine 123