Abstract: Objective　To investigate targeting delivery of a peptide with high affinity to human breast cancer in different types of human breast cancer cells. Methods　Gene of peptide was clone into pGEX-2T vector. The fusion proteins of glutathione-S-transferase (GST) and peptide sequence CASPSGALRSC (PⅠ), named GST-PⅠ, were expressed in BL21 (DE3) and purified by GST affinity column. The purified fusion protein was detected by SDS-PAGE and Western-blotting. Immunostaining analysis was used to determine the transduction of GST-PⅠ fusion protein into the MDA-MB-231 cells and other three human breast cancer cell lines were selected as control. Results　A series of pGEX-2T-PⅠ vectors were constructed. The result of Western-blotting showed that the fusion protein was well immunoreacted with the mouse anti Schistosom a japonica GST monoclonal antibody. Immunostaining analysis showed that, contrasted to controls, GST-PⅠ could targetingly permeate into the MDA-MB-231 cells. Conclusions GST-PⅠ, a fusion protein with expected molecular mass, was expressed. PⅠ can mediate the fusion proteins across the cell membrane. It can be used as a targeting vector to delivery bimolecular agent in gene therapy cases of breast cancer.

Key words: Breast cancer, Gene therapy, Vector