[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.

[Effect of TRAIL gene in human squamous cell carcinoma cell line induced by adenovirus].

OBJECTIVE: To study the apoptotic effect on the squamous cell carcinoma cell line TCa83 induced by recombined adenovirus vector containing TRAIL gene and CMV promoter. METHODS: The TCa83 cell line was firstly infected with different titre of AdCMV-EGFP containing enhanced green fluorescence protein gene (EGFP) as control, and investigated the transducing rate through fluorescence to obtain the definite titre. Then TCa83 cell line was infected with AdCMV-TRAIL in proper titre, and TRAIL gene was detected by means of RT-PCR. After TCa83 cell line was infected with AdCMV-TRAIL and AdCMV-EGFP at day 1, 3, 5, 7, the activity of TCa83 cell line were evaluated by MIT and the apoptosis were detected by flow cytometer. RESULTS: Proper titre was of 1,000 particles/cell, and TCa83 cell line could be infected 100% in this titre. TRAIL gene was detected by RT-PCR after infected with AdCMV-TRAIL. The activity of TCa83 decreased in both groups, but the AdCMV-TRAIL group decreased more sharply than AdCMV-EGFP group (P < 0.001). Both AdCMV-TRAIL and AdCMV-EGFP could lead to apoptosis of TCa83 cells, but the AdCMV-TRAIL, function stronger than AdCMV-EGFP. Especially there was remarkable statistic difference between two groups (P < 0.0001). CONCLUSION: AdCMV-TRAIL could effectively decrease the activity of TCa83 cell line and induce apoptosis.