Inhibition of GRP78 expression reverses cisplatin resistance in human ovarian cancer

Abstract

To explore the effects of GRP78 suppression on the sensitivity to cisplatin and elucidate the role and mechanism of GRP78 in ovarian cancer cisplatin resistance. The GRP78 siRNA expression plasmid was constructed to suppress GRP78 expression. Cell viability was detected by methyl thiazolyl tetrazolium (MTT) assay. Endoplasmic reticulum stress-related apoptosis related protein expressions were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. And cell apoptosis was detected by flow cytometry. The expressions of GRP78, CHOP and cleaved-caspase 4 were induced significantly by cisplatin (6 mg/L) in SKOV3 cells. And the expression of GRP78 was induced significantly by cisplatin in SKOV3/DDP cells. But the expressions of CHOP and cleaved-caspase 4 showed no significant difference. Inhibition of GRP78 expression and cisplatin combined treatment significantly increased the expressions of cleaved-caspase 4 and cleaved-caspase 3 in SKOV3/DDP cells. Inhibition of GRP78 expression reduced the cisplatin-induced up-regulations of p-Akt and p-mTOR and induced XBP1 mRNA shear expression and CHOP mRNA expression. Inhibition of GRP78 expression reverses cisplatin resistance in SKOV3/DDP cells. The mechanism may be through the activity of Akt/mTOR signaling pathway, CHOP expression levels and caspase activity.