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Modulation of doxorubicin sensitivity by cyclosporine A in hepatocellular carcinoma cells and their doxorubicin‐resistant sublines
Author(s) -
Shiraga Kunihiro,
Sakaguchi Kohsaku,
Senoh Tomonori,
Ohta Takeyuki,
Ogawa Shin,
Sawayama Tomoyuki,
Mouri Hirokazu,
Fujiwara Akiko,
Tsuji Takao
Publication year - 2001
Publication title -
journal of gastroenterology and hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.214
H-Index - 130
eISSN - 1440-1746
pISSN - 0815-9319
DOI - 10.1046/j.1440-1746.2001.02457.x
Subject(s) - doxorubicin , p glycoprotein , cell culture , multiple drug resistance , hepatocellular carcinoma , medicine , viability assay , ic50 , verapamil , mtt assay , efflux , microbiology and biotechnology , pharmacology , biology , drug resistance , chemotherapy , cancer research , biochemistry , genetics , calcium
Background and Aims: Cyclosporine A (Cys) and verapamil (Ver) sensitize multidrug‐resistant (MDR) cells to various anticancer drugs by interacting with membrane glycoproteins involved in the drug efflux. In the present study, we assessed the effect of Cys on the modulation of doxorubicin (DOR) sensitivity in hepatocellular carcinoma (HCC) cell lines, and their DOR‐resistant sublines. Methods: The sensitivity to DOR and the chemosensitizing effects of Cys were assessed by using two human HCC cell lines, PLC/PRF/5 and Hep‐3B, and their DOR‐resistant sublines, PLC/DOR and 3B/DOR. The expression of multidrug resistance 1 (MDR1) and multidrug resistance‐associated protein (MRP) mRNA in these cells were detected by using a RT‐PCR. The HCC cell lines grown in individual wells of 24‐well plates were incubated with DOR that were sequentially diluted in culture medium in combination with 5 μmol/L Cys for 24 h. The cell viability in each well was measured by using a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. Results: The mRNA of MDR1 and that of MRP were readily detectable in the HCC cell lines by RT‐PCR. When 5 μmol/L Cys was added to the culture, the 50% inhibiting concentration (IC 50 ) of DOR was reduced from 0.93 ± 0.29 μg/mL to 0.32 ± 0.10 μg/mL in PLC/PRF/5, and from 0.25 ± 0.07 μg/mL to 0.09 ± 0.04 μg/mL in Hep‐3B. Furthermore, in the presence of 5 μmol/L Cys, the IC 50 of DOR was reduced from 48.63 ± 17.04 μg/mL to 0.49 ± 0.14 μg/mL in PLC/DOR, and from 4.60 ± 1.22 μg/mL to 0.15 ± 0.06 μg/mL in 3B/DOR. The amounts of PCR products of MDR1 mRNA in PLC/DOR and 3B/DOR were greater than those in PLC/PRF/5 and Hep‐3B, respectively. Conclusions: In HCC, the amplification of MDR1 mRNA is probably the main mechanism underlying acquired DOR resistance. Cyclosporine is also indicated to be highly active in potentiating the anticancer activity of DOR in HCC cells and their DOR‐resistant sublines.