DJ-1 overexpression confers the multidrug resistance phenotype to SGC7901 cells by upregulating P-gp and Bcl-2

Gastric cancer (GC) is one of the most malignant tumors with high incidence and mortality worldwide, and the multidrug resistance (MDR) often results in chemotherapy failure in GC. DJ-1 has been well indicated to be associated with drug resistance in multiple cancers. However, the role of DJ-1 in the MDR of gastric cancer cells and its possible mechanism remain to be elucidated. Therefore, the current study was investigated whether DJ-1 expression is differential in parental gastric cancer cell SGC7901 and vincristine (VCR)-induced gastric cancer MDR cell SGC7901/VCR, and whether DJ-1 plays a significant role in development of MDR in gastric cancer. The results showed that DJ-1 expression in SGC7901/VCR cells was significantly higher than its sensitive parental SGC7901 cells. Furthermore, DJ-1 overexpressed gastric cancer cell line SGC7901/LV-DJ-1 led to the increase of cell survival rate, the IC50 of chemotherapeutic drugs and number of cell clones as well as decrease of cell cycle G0/G1 phase ratio compared with its parental cells under the treatment of VCR, adriamycin (ADR), 5-Fluorouracil (5-FU) and cisplatin (DDP). However, the DJ-1 knockdown stable cell line SGC7901/VCR/shDJ-1 reversed the above mentioned series of MDR. Moreover, it was found that upregulation of DJ-1 protein expression promoted the pumping rate of GC cells to ADR and reduced the apoptotic index of GC cells treated with chemotherapeutic drugs by upregulating P-gp and Bcl-2. Similarly, knocking down DJ-1, P-gp or Bcl-2 displayed a converse effect. In conclusion, the current study demonstrated that DJ-1 overexpression confers the MDR phenotype to SGC7901 cells and this process is related to DJ-1 promoting active efflux of drugs and enhancing the anti-apoptotic ability of MDR GC cells by upregulating P-gp and Bcl-2.