[Effect of PDMP, a glucosylceramide synthase inhibitor, on reversion of daunorubicin resistance in human leukemia cell line K562/A02].
This study was purposed to investigate the reversal effect of glucosylceramide synthase (GCS) inhibitor D, L-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) hydrochloride, on multidrug resistance in K562/A02 cells and its mechanism. The IC(50) (the half maximal inhibitory concentration) of PDMP was measured by MTT method. Cell apoptosis and intracellular daunorubicin (DNR) concentration were detected by flow cytometry. The expression of GCS and mdr1 genes were assayed by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot. The results showed that the IC(50) of DNR in K562 and K562/A02 cells were 0.23 +/- 0.02 and 7.15 +/- 0.24 microg/ml respectively. When the concentration of PDMP was equal to or less than 20 micromol/L ( < / = 20 micromol/L), the obviously inhibitory effect on proliferation of K562 and K562/A02 cells was not observed, but both 20 micromol/L and 10 micromol/L PDMP could enhance the sensitivity of K562/A02 cells to DNR (p < 0.01) and the reversal multiples were 2.59 and 1.69 respectively. After treating with 20 micromol/L and 10 micromol/L PDMP for 48 hours, the concentration of DNR in K562/A02 cells increased (p < 0.05) and the apoptotic rate also was elevated (p < 0.01). The expressions of GCS and mdr1 genes were down-regulated at mRNA and protein levels after treating K562/A02 cells with 20 micromol/L PDMP for 48 hours. It is concluded that PDMP can enhance the sensitivity of K562/A02 cells to DNR by increasing cell apoptosis rate and accumulation concentration of DNR in cells, which may be related to down-regulated expressions of GCS and mdr1 genes.
Department of Hematology, The Affiliated Zhongda Hospital, Southeast University Clinical Medical College, Nanjing 210009, Jiangsu Province, China.
Li
L
Yin
Bao-An
BA
Chen
Jian
J
Cheng
Jia-Hua
JH
Ding
Chong
C
Gao
Yun-Yu
YY
Sun
Jun
J
Wang
Gang
G
Zhao
Feng
F
Gao
Hui-Hui
HH
Song
Wen
W
Bao
Wei-Wei
WW
Wu
Fei
F
Wang
Yi-Qiong
YQ
Liang
Guo-Hua
GH
Xia
Xue-Mei
XM
Wang
D003630:Daunorubicin / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D020128:Inhibitory Concentration 50; D020014:K562 Cells; D009025:Morpholines / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D009025:Morpholines; C033110:RV 538; D003630:Daunorubicin