Cloning of HSA-GHGKHKNK fusion protein cDNA and its experssion in Pichia pastoris

GHGKHKNK octapeptide has tumoricidal potential mainly due to the amino acid residues of His-Gly-Lys motif inhibits the clone formation, adhesion and invasion of tumor cells. However, its clinical application is limited by its short half-life time in vivo. We used human serum albumin (HSA) fusion technology to fuse GHGKHKNK octapeptide and HSA to prolong half-life time of GHGKHKNK octapeptide and increase its stability. the GHGKHKNK - HSA fusion protein gene was cloned into the secretor type expression vector pPICZaC and subsequently expressed in Pichia pastoris. The supernatant fusion protein was detected by SDS-PAGE and purified with Blue Sepharose 6 Fast Flow chromatography. The clone formation rate of melanoma B16-F10 cell strain and the effect of the octapetide on the expression level of LN-R, ICAM-1 in melanoma B16-F10 cell strain were measured. Results suggested that infusion reaction between GHGKHKNK octapeptide and HSA did not destroy biologic activity of GHGKHKNK octapeptide.