URI, a
prefoldin family member, has been implicated roles in
cancer development. We have previously shown that URI can attenuate DNA damage in
gastric cancer cells treated with
potassium dichromate. The aim of this study was to investigate how URI involves
cisplatin-induced DNA damage response (DDR) in
gastric cancer cells and its possible mechanism relating to the ATM/CHK2 pathway. Here, MGC-803 and SGC-7901
gastric cancer cells were treated with different concentrations of
cisplatin. Comet assay was used to detect DNA damage and the results confirmed the dose-effect of
cisplatin-induced DNA damage in
gastric cancer cells. URI knockdown cell lines were established with
siRNA transfection. Cell viability and proliferation were detected by counting kit 8 (CCK-8) and
5-ethynyl-2'-deoxyuridine (EdU) assays respectively. Apoptosis and cell cycle were analyzed by flow cytometry. The results indicated that URI knockdown increased the sensitivity of cells to
cisplatin by inhibiting proliferation and promoting apoptosis. The levels of P-ATM, P-CHK2 and γH2AX were detected by Western blot. Increased levels of P-ATM, P-CHK2, and γH2AX were observed in
cisplatin treated cells, indicating that
cisplatin induced
a DNA damage response (DDR). URI knockdown in
cisplatin-treated cells significantly decreased the levels of P-ATM and P-CHK2 at 12 hours, but not at 0 and 6 hours after
drug withdrawal, while significantly increased γH2AX levels were detected at 6 hours, but not at 0 and 12 hours after
drug withdrawal compared with the control cells. However, the levels of γH2AX were significantly increased in URI knockdown cells after
cisplatin treatment for 12 hours. The cell cycle analysis showed that the number of cells entering S phase was significantly reduced and the cells were arrested in the G1 phase in URI-silenced
cisplatin-exposed cells, indicating that cell cycle progression was inhibited. In conclusion, our results suggest that URI is involved in the
cisplatin-induced DNA damage response via the ATM/CHK2 pathway, and silencing URI can increase
cisplatin-induced DNA damage and enhance
drug sensitivity in
gastric cancer cells.