Effect of B-cell translocation gene 2 alteration on radiosensitivity of cancer cells

Objective To investigate the effects of B-cell translocation gene 2(BTG2) overexpression on the radiosensitivity of cancer cells.

Methods Cancer cells with overexpression of BTG2 were established via stable transfection of full-length human BTG2 cDNA which was inserted into a mammalian expression plasmid pcDNA3(pcDNA3-BTG2). Cell survival was determined by thiazolyl blue tetrazolium bromide (MTT) and clonogenic survival assays. Protein-protein interaction was performed by immune precipitation(IP)-Western blot assay. Protein expression was assayed by Western blot assay.

Results As demonstrated in MTT assay and clonogenic survival assay, enforced expression of BTG2 significantly enhanced radiosenstivity of human breast cancer MCF-7 and MAD-MB-231 cells. The BTG2 protein was able to be determined in the breast cancer susceptibility gene1(BRCA1) IP. Silence of BRCA1 enhanced the increased radiosensitivity by BTG2, however, co-overexpression of BRCA1 reduced the BTG2-mediated radiosenstivity. Finally, the radiosensitivity of lung cancer cell lines tested exhibited a positive relationship with the levels of BTG2 protein expression and a negative correlation with the levels of BRCA1 protein expression.

Conclusion The present study further demonstrates that there is a significant relationship of radiosenstivity with BTG2 and BRCA1 expression, suggesting that BTG2 may be a new and important target in cancer radiotherapy via its binding to BRCA1.