[Chloroquine increased radiosensitivity of radioresistant MDA-MB 231 cells and its molecular mechanism].

OBJECTIVE

To study the genes associated with CQ (Chloroquine) increased radiosensitivity in radioresistant MDA-MB 231 cells.

METHODS

The survival curve of MDA-MB 231 breast cancer cells was establish in the presence or absence of CQ after irradiation by colongenic assay. The relationship between certain protein expressions (MLH1, ERCC1, PARP, RAD51, XRCC4) and CQ increased radiosensitivity in radioresistant MDA-MB 231 cells was examined by Western blot method. The genes which are associated with CQ increased radiosensitivity were studied by microarray analysis.

RESULTS

CQ increased deaths of parental MDA-MB 231 cells, radiosensitive MDA-MB 231 cells and radioresistant MDA-MB 231 cells were compared with those of the CQ-untreated control cells after irradiation, and the Radiation Potentiation Factor were 1.21-1.23. The expression of ERCC1 in the presence and absence of CQ in the radioresistant cells was significantly higher than that of sham-irradiated control cells by Western blot method. After irradiation, RAD51 level was increased up to 3-hour radiation and then gradually reduced. The expression of MLH1 was lower in 24 hours than that of other time points after irradiation. There were no differences on the expressions of MLH1, ERCC1, RAD51 in cells with and without CQ, which suggested that these genes weren't correlated with CQ increased radiosensitivity. XRCC4 and PARP levels were not changed by irradiation. Microarray analysis showed that TNP3, FRIH, CA21, ADTA genes might be related to CQ increased radiosensitivity in radioresistant cells.

CONCLUSION

CQ can increase radiosensitivity in radioresistant MDA-MB 231 breast cancer cells. It is not related to MLH1, ERCC1, PARP, RAD51, XRCC4 genes. TNP3 may play an important role in CQ increase radiosensitivity in radioresistant MDA-MB 231 breast cancer cells.