[Reversal effect of nuclear factor-κB protease inhibitor PDTC on multidrug resistance of K562/AO₂ cells and its mechanism].
This study was purposed to investigate the relationship between activation of nuclear factor-κB (NF-κB) and multidrug resistance in K562/AO₂ cells and its mechanism. Human erythroleukemic cell line K562 and its adriamycin-resistant counterpart K562/AO₂ cells were used in the study. After inhibiting the activation of NF-κB with noncytotoxic concentration of antioxidant pyrrolidine dithiocarbamate (PDTC) in vitro, the multiple of drug resistance of K562/AO₂ cells was assessed by MTT assay. RT-PCR and flow cytometry method were used to detect the relative expression of mdr-1 mRNA and P-gp, respectively. The results showed that (1) multidrug resistance of K562/AO₂ cells to ADM was 59 times higher than that of K562 cells. When being pretreated with 0.2 μmol/L PDTC which is noncytotoxic to cells, the IC₅₀ of ADM in K562/AO₂ cells was sharply decreased with relative reverse efficiency of 93.03%, which was more higher than that of classic modifying agents Verapamil (Ver); (2) NF-κB activity of K562/AO₂ cells was significantly higher than that of K562 cells (p < 0.01). When being treated with PDTC, the activation of NF-κB was sharply decreased in K562/AO₂ cells; with 0.2 μmol/L PDTC for 24 hours it decreased to the lowest, nearly to the K562 cell level (p > 0.05); (3) the relative expression of both mdr-1 mRNA and P-gp in K562/AO₂ cells was more higher; the expressions of mdr-1 mRNA and P-gp both were inhibited in K562/AO₂ cell group treated with PDTC for 48 hours. It is concluded that the PDTC used as an inhibitor of NF-κB activity can partially reverse the multidrug resistance of K562/AO₂ cells, which mechanism can be associated with the down-regulation of mdr-1 mRNA and P-gp.
Yang
Ting-Ting
TT
Department of Pediatrics, Lianyungang Municipal Frist People Hospital, Lianyungang 222002, Jiangsu Province, China.
Xue
Tian-Yang
TY
Xu
Wei
W
D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D006801:Humans; D020014:K562 Cells; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology*; D013859:Thiocarbamates / Q000494:pharmacology*
C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D016328:NF-kappa B; D011480:Protease Inhibitors; D011759:Pyrrolidines; D013859:Thiocarbamates; C020972:pyrrolidine dithiocarbamic acid