[The effect of arsenic trioxide (As2O3) combined with BSO on K562/ADM cell and its mechanisms].
OBJECTIVE
To investigate the apoptosis-induction, P-glycoprotein (P-gp) and mdr1 mRNA inhibition effects of arsenic trioxide (As2O3) and buthionine sulfoximine (BSO) on multidrug-resistant cell line K562/ADM cells, and to determine the relationship between intracellular GSH content and arsenic effect.


METHODS
K562/ADM cells were treated with arsenic (0.5, 2.0, 5.0 micromol/L) alone or combined with BSO (100 micromol/L). The cell proliferating capacity was assessed with MTT assay, and cell apoptosis by Annexin V and propidium iodide (PI) staining. Intracellular GSH contents were measured using a glutathione assay kit by spectrophotometry. P-gp expression was determined by flow cytometry, and mdr1 mRNA expression by semi-quantitative RT-PCR.


RESULTS
The GSH contents in K562/ADM cell was (81.13 +/- 3.91) mg/g protein. After the GSH contents were degraded by BSO, the K562/ADM cell proliferating capacity was obviously inhibited and the cells were induced apoptosis in 24 hours by the combination of clinic dose arsenic group (0.5, 2.0 micromol/L) and BSO (100 micromol/L). The cell apoptosis rates at 48 hours in arsenic alone group and combination group were (59.29 +/- 6.01)% and (65.06 +/- 8.29)%, and at 72 hours were (82.15 +/- 9.28)% and (92.72 +/- 9.41)% retrospectively. At 48 hours, the mdr1 mRNA inhibition effect of the combination group was obviously stronger than that of high dose arsenic alone group. At 72 hours, the P-gp inhibition effect of the combination group (clinic dose arsenic group, 0.5, 2.0 micromol/L) was obviously stronger than that of high dose arsenic alone group (5.0 micromol/L).


CONCLUSIONS
The intracellular GSH contents are closely correlated with the arsenic effect. The combination of conventional dose arsenic and BSO significantly induces K562/ADM cell apoptosis and inhibits P-gp and mdr1 mRNA expression in the cells.
Wang
Tao
T
Department of Hematology, The Second Hospital of Shanxi Medical University, Taiyuan 030001, China.
Ma
Liang-Ming
LM
Zhang
Hua-Ping
HP
Wang
Hong-Wei
HW
Yang
Lin-Hua
LH
Qiao
Zhen-Hua
ZH
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D019328:Buthionine Sulfoximine / Q000494:pharmacology*; D018432:Drug Resistance, Multiple / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D019450:Genes, MDR / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D010087:Oxides / Q000494:pharmacology*
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D001152:Arsenicals; D010087:Oxides; D019328:Buthionine Sulfoximine; D005978:Glutathione; D000077237:Arsenic Trioxide