Reversal of Multi-drug Resistance by PSUPER-shRNA-mdr1 in Vivo and in Vitro
Overview
Affiliations
Aim: To explore the possibility of reversing multi-drug resistance (MDR) to HepG2/mdr1 in vitro and in vivo with RNA interference (RNAi).
Methods: HepG2/mdr1 was obtained by cloning the whole gene mdr1 into HepG2 cells. shRNA targeting sequence was designed to be homologous to the P-gp encoding MDR1 mRNA consensus sequence. pSUPER-shRNA/mdr1 was constructed using the enzyme-digested technique. HepG2/mdr1 cells were transfected with vectors of pSUPER-shRNA/mdr1 to measure their efficacy by real-time PCR for mdr1 mRNA, flow cytometry (FCM) for P-gp expression, and Rhodamine efflux, MTT method for HepG2/mdr1 function, respectively. In vivo, mice tumors were treated by injecting pSUPER-shRNA/mdr1 in situ and into intra-abdominal cavity. Tumors were collected to create cell suspension and cryosections after chemotherapy with adriamycin and mytomycin. The cell suspension was incubated in RPMI-1640 supplemented with G418 to screen stable cells for appreciating the reversal of MDR. Cryosections were treated with immunohistochemistry technique to show the effectiveness of transfection and the expression of P-gp.
Results: pSUPER-shRNA/mdr1 was successfully constructed, which was confirmed by sequencing. The MDR phenotype of HepG2/mdr1 was decreased significantly in vitro transfection. HepG2/mdr1 showing its MDR was reversed notably in P-gp expression (11.0% vs 98.2%, P<0.01). Real-time PCR showed that mRNA/mdr1 was lower in test groups than in control groups (18.73+/-1.33 vs 68.03+/-2.21, P<0.001). Compared with HepG2, the sensitivity of HepG2/mdr1 and HepG2/mdr1-dsRNA cells to ADM was decreased by 1.64 times and 15.6 times, respectively. The accumulation of DNR in positive groups was decreased evidently. In vivo, the p-gp expression in positive groups was significantly lower than that in control groups (65.1% vs 94.1%, P<0.05). The tumor suppressing rate in test groups was 57.8%. After chemotherapy, the growth rate in test groups was lower than that in control groups (700.14+/-35.61 vs 1659.70+/-152.54, P<0.05). Similar results were also observed under fluorescence microscope, and confirmed by Image-Pro Plus 4.5 analysis.
Conclusion: pSUPER-shRNA/mdr1 vector system allows simple, stable and durable nonviral knockdown of P-gp by RNAi in malignant cells and animals to restore their sensitivity to adriamycin.
Zhang Y, Gao Z, Zhang X, Yuan Z, Ma T, Li G Exp Ther Med. 2021; 21(4):332.
PMID: 33732305 PMC: 7903486. DOI: 10.3892/etm.2021.9763.
Lin L, Wu M, Pidugu V, Ho I, Su T, Lee T Oncotarget. 2017; 8(28):45072-45087.
PMID: 28178691 PMC: 5542168. DOI: 10.18632/oncotarget.15065.
Zhang X, Zhang B, Liu J, Liu J, Li C, Dong W Sci Rep. 2015; 5:7835.
PMID: 25644501 PMC: 4314651. DOI: 10.1038/srep07835.
Methylation of SFRP5 is related to multidrug resistance in leukemia cells.
Wang H, Wang X, Hu R, Yang W, Liao A, Zhao C Cancer Gene Ther. 2014; 21(2):83-9.
PMID: 24434572 DOI: 10.1038/cgt.2013.87.
Coordinated targeting of the EGFR signaling axis by microRNA-27a*.
Wu X, Bhayani M, Dodge C, Nicoloso M, Chen Y, Yan X Oncotarget. 2013; 4(9):1388-98.
PMID: 23963114 PMC: 3824521. DOI: 10.18632/oncotarget.1239.