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Updated: Jul 17, 2026

Pooled shRNA Library Screening to Identify Factors that Modulate a Drug Resistance Phenotype
Published on: June 17, 2022
[Study on RNA interference reversing the multidrug resistance of leukemia cell]
Ling Gu1, Ting Liu, Yu-ping Gong
1Department of Hematology, West China Hospital, Sichuan University, Chengdu 610041, China.
Objective:
To downregulate the expression of mdr1 gene in K562/A02 cell line by RNA interference.
Methods:
The eukaryotic expression vectors of shRNA aiming at two mdr1 mRNA target sequences were constructed and used to transfect the drug resistance cell line K562/A02 with liposome-induced gene transfection. The mRNA of mdr1 gene was identified by Q-PCR. The P-gp expression of was detected by Western blot. The function of P-gp was measured by daunorubicin (DNR) efflux experiment and the sensitivity of cell lines to doxorubicin (ADM) was detected by MTT test.
Results:
Two shRNA plasmids targeting mdr1 mRNA were constructed and cloned. Two mdrl-targeted shRNA could down-regulate mdr1 mRNA expressions with 89.74% and 87.18% respectively, almost completely down-regulate the P-gp expression. The intracellular DNR increased after RNAi treating. The daunorubicin efflux ratio at 60 min were 13.16% and 22.02%, compared with control 40.44% , 45.31%, P<0.05. MTT test demonstrated the relative reversing efficiencies to doxorubicin were 84.36% and 76.69% respectively. CONCLUSION RNA interference can effectively reverse multidrug resistance caused by mdr1.
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