[Effect of small interfering RNA targeting multidrug resistance-related protein and bcl-2 on drug resistance and apoptosis of K562 and K562/ADM cells].
OBJECTIVE
To observe the effect of small interfering RNA (siRNA) targeting multidrug resistance-related protein (MRP) and bcl-2 genes in modulating drug resistance and apoptosis of K562 and K562/ADM cells.


METHODS
Two siRNA constructs targeting respectively bcl-2 and MRP genes, were synthesized and transfected either alone or in combination into K562 and K562/ADM cells via lipofectamine2000. MTT assay was used to evaluate the viability of the transfected cells at 24, 48 and 72 h Post-fransfection, and RT-PCR was performed to determine the mRNA levels of bcl-2 and MRP. The effects of MRP siRNA and bcl2 siRNA on the apoptosis and the protein expression of Bcl-2 and MRP were evaluated with flow cytometry.


RESULTS
In K562/ADM cells, the IC (50) decreased from 12.81 microg/ml (ADM group) to 3.74 microg/ml (ADM+MRP siRNA group), 6.82 microg/ml (ADM+bcl2 siRNA group) and 2.51 microg/ml (ADM+MRP siRNA+bcl2 siRNA). Similarly, in K562 cells, the IC50 decreased significantly from 6.75 microg/ml (ADM) to 3.22 microg/ml (ADM+MRP siRNA), 3.56 microg/ml (ADM+bcl2 siRNA) and 1.84 microg/ml (ADM+MRP siRNA+bcl2 siRNA) (P<0.05). Flow cytometry demonstrated significantly increased apoptosis of the cells following MRP siRNA and bcl2 siRNA transfection, which also resulted in significantly decreased expressions of MRP and bcl-2 proteins (P<0.05).


CONCLUSIONS
Treatment with both MRP and bcl-2 siRNAs inhibits the target gene expression, and increases the drug sensitivity and apoptosis of K562 and K562/ADM cells.
Song
Zhao-yang
ZY
Department of Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China. zhaoyangsong@163.com
Hu
Hai-yan
HY
Deng
Lan
L
Wu
Bing-yi
BY
Guo
Kun-yuan
KY
Zhang
Mei-xia
MX
D018435:ATP Binding Cassette Transporter, Subfamily B / Q000235:genetics*; D017209:Apoptosis / Q000235:genetics; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D006801:Humans; D020014:K562 Cells; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics*; D014162:Transfection
D018435:ATP Binding Cassette Transporter, Subfamily B; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D004317:Doxorubicin