Enhanced cell gap junctions promotes the radiosensitivity in triple negative breast cancer cells / 实用肿瘤学杂志

ABSTRACT

Objectvi e To investigate whether promoting gap junctions may contribute to the radiosensi-tivity in triple negative breast cancer( TNBC)cells.Methods HCC70(triple-negative),MCF-7(ER-posi-tive)or SK-BR3(HER2-positive )cells were transfected with pcDNA/5 -Cx43 expression plasmid using liposome 2000.The transfected cells were treated with various doses of radiation(0,5,10,15 Gy),and the level of Cx43 protein was determined by Western blot and the cell connectivity was determined by fluorescent tracer technique. Cell proliferation inhibition,clone formation ability and apoptosis were detected using MTT,clone formation assay, AnnexinV-FITC/PI double staining and flow cytometer,respectively.Results The level of Cx43 protein signifi-cantly increased in HCC 70 -Cx43 ,MCF-7 -Cx43 and SK-BR3 -Cx43 cells.After transfection the cells were treated with various doses of radiation,level of Cx43protein was gradually enhanced in dose dependent fashion .The re-sults form fluorescent tracer technique showed that fluorescence intensity was gradually elevated with increase of radiation doses.Cell viability and clone formation ability were decreased gradually in dose dependent manner in HCC70-Cx43 ,MCF-7 -Cx43 and SK-BR3-Cx 43 cells.Unexpectedly,the inhibitive effect of proliferation ability and clone formation ability in HCC70 -Cx43 cell was higher than in MCF-7 -Cx43 and SK-BR3 -Cx43 cells under same conditions.The results from AnnexinV-FITC/PI and flow cytometer showed that apoptosis rate was enhanced gradually accompanying with increase of radiation doses.Conclu sion Enhancing the function of cell gap junc-tions promoted radiosensitivity of breast cancer cells,particularly in TNBC cells.Radiation can strengthen cell gap junctions in breast cancer cell and cytotoxicity of TNBC cell can be enhanced by both synergistic effects.