Objective      To investigate the effect of NANOG knockdown on multidrug resistance gene 1 (MDR1) expression and doxorubicin chemosensitivity of human hepatocarcinoma HepG2 cells.       Methods      Transient transfection of the specific siRNA targeting NANOG gene into HepG2 cells was performed. The expression of NANOG and MDR1 at mRNA and protein levels was de

tected by real-time PCR and Western blotting. The influence of NANOG knockdown on cell proliferation ability was examined by colony formation assay. The influence on cell cycle was tested by flow cytometry. The doxorubicin chemosensitivity of HepG2 cells was detected by CCK-8 assay.       Results      Transfection of the specific siRNA targeting NANOG gene into HepG2 cells could effectively inhibit the expression of NANOG mRNA and protein

with the ratio of siRNA group to mock group of 0.32±0.05 and 0.38±0.08

respectively. Compared with mock group

the siRNA-mediated silencing of NANOG gene in HepG2 cells resulted in decreased cell clone formation rate [(8.51±3.63)% vs (17.13±2.24)%

P

0.05

]

increased proportion of cells in G

0

/G

1

phase [(75.33±8.21)% vs (57.81±5.05)%

P

0.05

]

and increased chemosensitivity to doxorubicin (

P

0.05). Furthermore

knockdown of NANOG gene caused the down-regulation of MDR1 mRNA and protein expression

with the ratio of siRNA group to mock group of 0.35±0.06 and 0.41±0.08

respectively.       Conclusion      Inhibition of NANOG expression in HepG2 cells causes down-regulation of MDR1 expression and enhances the chemosensitivity of cells to doxorubicin.