Reversal of multidrug resistance of hepatocellular carcinoma cells by metformin through inhibiting NF-κB gene transcription.
OBJECTIVE
To interfere with the activation of nuclear factor-κB (NF-κB) with metformin and explore its effect in reversing multidrug resistance (MDR) of hepatocellular carcinoma (HCC) cells.


METHODS
Expression of P-glycoprotein (P-gp) and NF-κB in human HepG2 or HepG2/adriamycin (ADM) cells treated with pCMV-NF-κB-small interference RNA (siRNA) with or without metformin, was analyzed by Western blot or fluorescence quantitative PCR. Cell viability was tested by CCK-8 assay. Cell cycle and apoptosis were measured by flow cytometry and Annexin-V-PE/7-AnnexinV apoptosis detection double staining assay, respectively.


RESULTS
P-gp overexpression in HepG2 and HepG2/ADM cells was closely related to mdr1 mRNA (3.310 ± 0.154) and NF-κB mRNA (2.580 ± 0.040) expression. NF-κB gene transcription was inhibited by specific siRNA with significant down-regulation of P-gp and enhanced HCC cell chemosensitivity to doxorubicin. After pretreatment with metformin, HepG2/ADM cells were sensitized to doxorubicin and P-gp was decreased through the NF-κB signaling pathway. The synergistic effect of metformin and NF-κB siRNA were found in HepG2/ADM cells with regard to proliferation inhibition, cell cycle arrest and inducing cell apoptosis.


CONCLUSIONS
Metformin via silencing NF-κB signaling could effectively reverse MDR of HCC cells by down-regulating MDR1/P-gp expression.
Wei Wu, Jun-Ling Yang, Deng-Fu Yao, Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
Wei
W
Wu
Wei Wu, Jun-Ling Yang, Deng-Fu Yao, Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
Jun-Ling
JL
Yang
Wei Wu, Jun-Ling Yang, Deng-Fu Yao, Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
Yi-Lang
YL
Wang
Wei Wu, Jun-Ling Yang, Deng-Fu Yao, Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
Han
H
Wang
Wei Wu, Jun-Ling Yang, Deng-Fu Yao, Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
Min
M
Yao
Wei Wu, Jun-Ling Yang, Deng-Fu Yao, Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
Li
L
Wang
Wei Wu, Jun-Ling Yang, Deng-Fu Yao, Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
Juan-Juan
JJ
Gu
Wei Wu, Jun-Ling Yang, Deng-Fu Yao, Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
Yin
Y
Cai
Wei Wu, Jun-Ling Yang, Deng-Fu Yao, Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
Yun
Y
Shi
Wei Wu, Jun-Ling Yang, Deng-Fu Yao, Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
Deng-Fu
DF
Yao
Hepatocellular carcinoma; Metformin; Multidrug resistance; Reversal