Soluble expression and activity evaluation of SDF-1/54R, a specific antagonist of CXCR7 / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a soluble prokaryotic expression vector of the CXCR7-specific antagonist SDF-1/54R and evaluate its activity.</p><p><b>METHODS</b>SDF-1/54r gene amplified by PCR was inserted into the soluble expression vector pET-41a+ engineered with GST fusion tag, and the recombinant vector was transformed into E. coli strain BL21 (DE3). After IPTG induction of E. coli, the expressed recombinant protein was purified with GST affinity chromatography purification system and confirmed by SDS-PAGE and Western blotting assay. The target protein SDF-1/54R was obtained after digestion of the purified product with enterokinase. Breast cancer MCF-7 cells with high expression of CXCR7 was treated with SDF-1/54R and the cell proliferation and metastasis was evaluated with MTT and chemotaxis assays.</p><p><b>RESULTS</b>The target protein SDF-1/54R obtained showed an obvious inhibitory effect on the proliferation and metastasis of MCF-7 cells as confirmed by MTT and chemotaxis assays.</p><p><b>CONCLUSION</b>SDF-1/54R is a good antagonist of CXCR7 and shows a potential value as an effective anti-cancer agent.</p>

Construction of SDF-1P2G54, a specific antagonist of CXCR4 / 南方医科大学学报

<p><b>OBJECTIVE</b>To obtain a specific antagonist of CXCR4, SDF-1P2G54 by mutating SDF-1 second proline (P) into glycin (G) and removing the α-helix of its C-terminal.</p><p><b>METHODS</b>SDF-1p2g54 gene amplified by PCR was inserted into the vector pET-30a (+) and transformed into Escherichia coli (E. coli) strain BL21. After IPTG induction of E. coli, the expressed recombinant protein was purified with nickel-affinity chromatography column under denaturing conditions and refolded with gradient dilution and ultra-filtration. The chemotactic effect of SDF-1P2G54 on Jurkat cells and its antagonistic effect against SDF-1 were determined by transwell assay; flow cytometry was used to assay the ability of SDF-1P2G54 to induce calcium influx and CXCR4 internalization in MOLT4 cells.</p><p><b>RESULTS</b>The recombinant protein SDF-1P2G54 completely lost the functions to activate CXCR4 or to induce transmembrane migration of Jurkat cells and calcium influx in MOLT4 cells, but maintained a high affinity to CXCR4. SDF-1P2G54 effectively inhibited the chemotactic effect of wild-type SDF-1 to Jurkat cells, and induced rapid CXCR4 internalization in MOLT4 cells.</p><p><b>CONCLUSION</b>SDF-1P2G54 is a new antagonist of CXCR4 with a potential value as an effective inhibitor of HIV-1 infection, cancer metastasis or other major diseases.</p>