Home > Browse Issues > Vol.39 No.11
The Study on Regulation of Endoplasmic Reticulum Stress in Polyphyllin I-Induced Apoptosis in Human Hepatocellular Carcinoma HepG2 Cells
Yang Dandan1, Qi Qi1, Chen Zhengli1,2, Chen Bing1, Huang Chao1,2, Luo Qihui1,2*, Liu Wentao1,2
1Laboratory of Animal Disease Model, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China; 2Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
Abstract: This work was aimed to investigate the role of endoplasmic reticulum stress in polyphyllin I-induced apoptosis in human hepatocellular carcinoma HepG2 cells. HepG2 cells were treated with the different concentrations of polyphyllin I for 6， 12， 24 h， the inhibition of cell proliferation was detected by CCK-8; the qRTPCR (Real-time quantitative PCR) was applied to detect GRP78， ATF-6， IRE-1 and PERK mRNA levels; Western blot was applied to determine the protein levels of Cleaved-caspase12， Caspase-12， Cleaved-caspase3， Bax， Bcl-2， IRE-1， XBP1， CHOP and P-JNK1; the flow cytometry was applied to detect the effect of 20 mmol/L 4-PBA on apoptotic rate. The result showed that polyphyllin I could inhibit the proliferation and induce apoptosis of HepG2 cells in dose- and time-dependent manners; qRT-PCR results showed that the levels of ATF-6 and PERK mRNA had no obvious change， but the levels of GRP78 and IRE-1 mRNA increased significantly， compared with the negative control group (P<0.05); Western blot results showed that polyphyllin I could up-regulate the levels of apoptotic proteins Bax and Cleaved-caspase3， and down-regulate the level of the anti-apoptotic protein Bcl-2. Our further study revealed that polyphyllin I could up-regulate the levels of endoplasmic reticulum stress proteins IRE-1 and Cleaved-caspase12， and down-regulate the levels of P-JNK1 and XBP1 proteins， while the protein level of CHOP was no significant difference (P>0.05). Flow cytometry results showed that the apoptotic rate increased significantly in combination group of 4-PBA with 2.5 μmol/L polyphyllin I (P<0.01). In conclusion， endoplasmic reticulum stress was involved in polyphyllin I inducing HepG2 cells apoptosis， which played a protective role in this process.
CN
EN