[Mechanism of chloroquine in promoting sensitivity of chemotherapeutics in oral squamous cell carcinoma CAL-27 cell line to cisplatin].

PURPOSE

To study the role and mechanism of autophagy in chemotherapy of oral squamous cell carcinoma, and provide theoretical evidence to improve chemotherapeutic efficacy of oral squamous cell carcinoma patients.

METHODS

The cell survival rate changes induced by cisplatin (DDP) and chloroquine (CQ) in CAL-27 cells were assayed by methyl thiazolyl tetrazolium method(MTT). The LC3-II expression level was detected by laser scanning confocal microscope; The apoptotic rate was determined by flow cytometry. SPSS17.0 software package was used for statistical analysis.

RESULTS

MTT results showed that compared with the control group, the cell survival rate reduced with the increasing time of DDP and CQ treatment; The optimal concentration of CAL-27 cells was 5 mg/L after treatment with CQ. IC50 of the CAL-27 cells was 5 mg/L after treatment with DDP; MTT results showed that the cell survival rate of CQ+DDP group was significantly lower than control group, CQ group and DDP group (P<0.05). With the action of CQ and DDP to CAL-27 cells for 48 hours, immunofluorescence results showed that the average fluorescence intensity of DDP group was significantly higher than the other 3 groups (P<0.05), while it was significantly lower in CQ group than the other 3 groups (P<0.05). With the action of CQ and DDP to CAL-27 cells for 48 hours, flow cytometry results showed that the cell apoptosis rate of DDP group and CQ+DDP group were significantly higher than control group and CQ group. The cell apoptosis rate of CQ+DDP group was significantly higher than DDP group (P<0.05). With the action of CQ and DDP to CAL-27 cells for 48 hours, cells in G1 phase of DDP group and CQ+DDP group increased, indicating G1 phase blockage. The cell count in G1 phase of CQ+DDP group was significantly higher than DDP group (P<0.05).

CONCLUSIONS

Inhibition of autophagy can enhance the chemotherapeutic sensitivity of DDP in CAL-27 cells. Autophagy in CAL-27 cells is an important mechanism for chemotherapy resistance of oral squamous cell carcinoma. Autophagy inhibitor may have significant potential to be a novel chemotherapeutic sensitizer for oral squamous cell carcinoma.