The construction and expression of tumor-targeting fusion protein RGD-hIL-24 and the study of its in vitro anti-tumor activity
Objective To construct and express tumor-targeting fusion protein RGD-hIL-24 in E. coli and to study its anti-tumor activity of inducing apoptosis and targeting tumor in vitro . Methods The fusion gene GRGDS fused with N-terminus of hTL-24 was obtained by PCR. Then it was cloned into expression vector pET-22b. RGD-hIL-24 was expressed in E. coli BL21(DE3) . The fusion protein was purified by chelating chromatog-raphy. The activity of inducing apoptosis of tumor cells was observed by MTT colorimetry and fluorescence staining. The activity of targeting tumor was analyzed by cell adhesion assay. Results The fusion gene was confirmed by gene sequencing. RGD-hIL-24 was expressed in E. coli as inclusion bodies ( Mr = 20 000) which took up to 26.47% of total somatic protein. It was identified by SDS-PAGE and Western blot. The purity of fusion protein reached over 90% . It induced the apoptosis of MCF - 7 cells and was targeted to tumor cells in vitro . Conclusion The fusion protein RGD-hIL-24 was successfully constructed and highly expressed in E. coli. It could induce tumor cells apoptosis and have the activity of tumor targeting.