Kanglaite inhibits the expression of drug resistance genes through suppressing PVT1 in cisplatin-resistant gastric cancer cells.

Kanglaite (KLT) was shown to alleviate the development of multidrug resistance (MDR) clinically. The purpose of this study is to examine the mechanism of KLT for chemotherapy resistance in gastric cancer cells involving the regulation of MDR-related proteins. The cisplatin-resistant BGC823/DPP and SGC7901/DDP cells were treated with 1, 2.5 and 5 µl/ml of KLT for 24, 36 and 48 h. Cell Counting Kit-8 (CCK-8) assay and flow cytometry were performed to detect the cell viability and cell apoptosis, respectively. The expression of MDR1 and multidrug resistance associated protein 1 (MRP1) were examined by quantitative PCR and western blotting in BGC823/DPP cells and SGC7901/DDP cells treated with KLT. The effect of KLT on the expression of PVT1 was investigated. PVT1-overexpression vector was constructed and transfected into BGC823/DPP cells and SGC7901/DDP cells which were treated with KLT. KLT inhibited the cell viability and promoted the cell apoptosis of BGC823/DPP cells and SGC7901/DDP cells in a concentration-dependent manner. KLT suppressed the expression of MDR1 and MRP1 and the level of PVT1. PVT1 overexpression reversed the increased percentage of apoptotic cells induced by KLT. Finally, we found that PVT1 overexpression also abrogated the effect of KLT on the mRNA level and protein level of MDR1 and MRP1 in BGC823/DPP and SGC7901/DDP cells. KLT inhibited the expression of MDR1 and MRP1 via suppressing the expression of PVT1, which suggested the potential mechanism of KLT involving in MDR in gastric cancer.