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Wogonoside reverses cisplatin resistance in SGC7901/cDDP cells through inhibition of PI3K/Akt/Nrf2/ARE signaling pathway

WANG Li-Jun^1,*, WANG Shi-Guang¹, DENG Tong-Xing²

¹Medical College, Zhengzhou University of Industrial Technology, Xinzheng 451150, China；²Department of Anatomy, Luohe Medical College, Luohe 462002, China

Abstract

The aim of this study was to investigate the effect of wogonoside (WGS) on the cisplatin (cDDP) resistance in human gastric carcinoma SGC7901/cDDP cells and its possible mechanism. The drug-resistant SGC7901/cDDP cells were established by stepwise exposure to cDDP. CCK-8 assay was employed to detect the cytotoxic effect of WGS and cDDP on SGC7901/cDDP cells, and the combined effect of WGS and cDDP was analyzed by Chou-Talalay method. Flow cytometry was used to determine the apoptosis and reactive oxygen species (ROS). Nuclear factor erythroid-2 related factor 2 (Nrf2) gene was knocked down by using the short hairpin RNA (shRNA) approach. The protein levels of Nrf2, NAD(P)H:quinone oxidoreductase 1 (NQO1), glutathione S transferase-π (GST-π), multidrug resistance-associated protein 1 (MRP1), cleaved Capase-3, p-Akt and Akt were detected by Western blotting. The result showed that after various concentrations of WGS and/or cDDP treatment for 48 h, the cell viability was remarkably reduced in a dose-dependent manner (P < 0.05). When the inhibition rate exceeded 16%, the combination of WGS and cDDP produced a synergistic effect. The protein levels of p-Akt, Nrf2 and MRP1 in SGC7901/cDDP cells were higher than those in SGC7901 cells (P < 0.05). WGS and LY294002 (PI3K inhibitor) both remarkably decreased the phosphorylation level of Akt (P < 0.05), down-regulated the protein level of Nrf2 (P < 0.05), increased the content of ROS (P < 0.05), up-regulated the protein level of cleaved Caspase-3 (P < 0.05), and induced apoptosis (P < 0.05). Meanwhile, N-acetyl-L-cysteine (NAC) decreased apoptosis and oxidative stress reaction induced by WGS (P < 0.05). WGS and Nrf2 gene silencing both down-regulated the protein levels of NQO1, GST-π and MRP1 (P < 0.05). These results suggest that WGS may reverse cDDP resistance in SGC7901/cDDP cells through blocking the PI3K/Akt/Nrf2/ARE signaling pathway, thus enhancing the cytotoxicity of cDDP and inducing oxidative stress reaction and apoptosis.

Key words: wogonoside; gastric carcinoma; cisplatin resistance; Nrf2; reactive oxygen species; Akt

Received: 2018-01-18　　Accepted: 2018-05-16

Corresponding author: 王丽君　　E-mail: wljwanglijun@163.com

DOI: 10.13294/j.aps.2018.0038

Citing This Article：

WANG Li-Jun, WANG Shi-Guang, DENG Tong-Xing. Wogonoside reverses cisplatin resistance in SGC7901/cDDP cells through inhibition of PI3K/Akt/Nrf2/ARE signaling pathway. Acta Physiol Sin 2018; 70 (4): 397-405 (in Chinese with English abstract).