[The relationship between cytochrome P450, subfamily IIIA, polypeptide 5 gene and drug resistance in leukemia cell lines].
OBJECTIVE
To investigate if the transcription, expression and activities of cytochrome P450, subfamily IIIA, polypeptide 5 gene (CYP3A5) are correlated with drug resistance in leukemia cell lines.


METHODS
Using RT-PCR, immunohistochemistry and reverse-phase high-performance liquid chromatography (HPLC) assay, CYP3A5 mRNA protein and activities in leukemia cell lines were detected. Daunorubicin (DNR) sensitivity profiles of leukemia cell lines were obtained with MTT assay. Cell cycle characteristics and apoptosis induced by DNR were observed with flow cytometry (FCM) analysis.


RESULTS
K562, U937, HL-60, NB4 and Jurkat cells were chosen as experimental cell line panels. It was found that CYP3A5 mRNA were measured only in K562 and U937 cells. CYP3A4 and CYP3A7 were not detectable in each cell line. The five leukemia cell lines presented sensitivity to DNR (IC(50), mg/L) in an order as follows: NB4 (0.068 +/- 0.036) > Jurkat (0.076 +/- 0.013) > HL-60 (0.092 +/- 0.016) > K562 (0.148 +/- 0.041) > U937 (0.150 +/- 0.035). Interestingly, K562 and U937 cells (cell lines with CYP3A5 gene transcription) were more resistant to DNR as compared with the other three cell lines in a statistically significant way (P < 0.01). Furthermore, expression and activities of CYP3A5 gene and cell cycle characteristics were observed in K562 and NB4 cells, which represented cell lines with or without CYP3A5 gene transcription respectively. In comparison with NB4 cells, K562 cells expressed CYP3A5 protein and showed a statistically significant higher CYP3A5 activity (3.075 +/- 0.036) x 10(-3) versus (1.635 +/- 0.196) x 10(-3), P < 0.05. FCM analysis showed that S phase cell proportions were similar in K562 and NB4 cells. Incubation with DNR (1 mg/L) for 6 hours induced a remarkable apoptosis peak in NB4 cells, while such peak not occur in K562 cells (apoptosis cell percentage 18.4% and 0.8% respectively).


CONCLUSIONS
Only CYP3A5 gene of CYP3A subfamily were detectable in leukemia cell lines, and its transcription, expression and activities were correlated with drug resistance in leukemia cell lines.
Department of Hematology, Renji Hospital of Shanghai Second Medical University, Shanghai Institute of Hematology, Shanghai 200001, China. jane_wt@hotmail.com
Ting
T
Wang
Fang-yuan
FY
Chen
Jie-ying
JY
Han
Ji-hua
JH
Zhong
Ye
Y
Teng
Ren-rong
RR
Ouyang
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D003630:Daunorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D015870:Gene Expression; D018922:HL-60 Cells; D006801:Humans; D019169:Jurkat Cells; D020014:K562 Cells; D007938:Leukemia / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic; D020298:U937 Cells
D000903:Antibiotics, Antineoplastic; D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System; C104464:CYP3A protein, human; C510164:CYP3A5 protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D003630:Daunorubicin