Effects of recombinant epidermal growth factor receptor antisense adenovirus combined with irradiation on breast cancer cells

Objective: To investigate the effects of a recombinant antisense adenovirus for epidermal growth factor receptor (EGFR) combined with irradiation on breast cancer cells. Methods: Human EGFR cDNA fragment was subcloned in the opposite orientation to the cytomegaloviral promoter and inserted into a E1/E3-deleted type 5 adenoviral vector to obtain AdE5 construct which expresses EGFR antisense RNA. Combined with γ-ray irradiation, its effects on clonogenicity and cell cycle phase distribution were studied in a human breast cancer line MDA-MB-23. Results: EGFR protein expression was dramatically inhibited in MDA-MB-231 cells after AdE5 infection. The post-irradiation clonogenicity was reduced by AdE5 in a viral and irradiation dose-dependent manner. Further cytometric analysis showed that AdE5 infection at a MOI of 300 pfu/cell induced a cell cycle progression from radio-resistant G0 + G1 phases to radiosensitive G2 + M phases, resulting in a synergistic effect after combination of these two treatments. Conclusions: The transduction of EGFR antisense RNA by adenoviral vector is effective for antisense strategy targeting EGFR, and increases the cell-killing effect of ionizing radiation on breast cancer cells.(authors)