Expression and characterization of bifunctional fusion proteins possessing antitumor and thrombolytic function for targeting therapy

Abstract

It is a usual clinical phenomenon that cancer patients are prone to thrombosis. Until now, there have been no efficient methods or appropriate drugs to prevent and cure tumor thrombus. ΔSEC2, N-terminal deletion of 17 amino acids and C-terminal deletion of 132 amino acids, retained antitumor activity of SEC2. ΔSak, N-terminal deletion of 10 amino acids, had thrombolytic activity and specificity advantages. By utilizing bioactivities of ΔSEC2 and ΔSak, ΔSEC2-ΔSak and ΔSak-ΔSEC2 were constructed. Octreotide is a tumor targeting peptide and it can be combined with somatostatin (SST) receptors of tumor surface in ligand-receptor binding way. It can be used to increase specificity for tumor therapy. Based on previous studies, DNA sequence encoding octreotide gene was inserted into plasmid pET-28a-Δsec2-Δsak and pET-28a-Δsak-Δsec2. After expression and purification, fusion proteins could significantly stimulate proliferation of mouse spleen lymphocyte, obviously inhibit the growth of human gastric carcinoma BGC-823, and have thrombolytic activity, indicating that fusion proteins retained bioactivities of staphylococcal enterotoxin C2 and Sak. Furthermore, tumor binding capacity of fusion protein was confirmed through the coimmunoprecipitation method. The result showed that they could bind SST receptor 2 antibody, indicating that fusion proteins could be specifically targeted to tumor surface. It has important significance and may be used for targeted therapy.

Production of a bioactive recombinant chicken matrix metalloproteinase‐11 peptide in Escherichia coli

“…Since removal of the propeptide from the MMP‐11 zymogen is a prerequisite for resuming its proteolyitc activity, the caseinolytic activity observed in this study in the recombinant cMMP‐11 peptide without activation by trypsin or APMA might be due to the lack of a larger portion of the propeptide in the peptide as compared with those reported earlier. The strategy of enhancing bioactivity of the recombinant peptide through deletion of few of the N‐terminal amino acids was also reported by other workers .…”

Effective prediction model for preventing postoperative deep vein thrombosis during bladder cancer treatment

“…Additionally, a previous study cloned the DNA sequence encoding the murine somatostatin octreotide gene into the pET-28a-Dsak-Dsec2 and pET-28a-Dsec2-Dsak plasmids. 33 The fusion protein, when expressed and purified, showed the thrombolytic activity of Dsak, which specifically activates the fibrinolytic system. 33 Therefore, administration of somatostatin to prevent DVT after surgery may cause an adjustment between the aforementioned systems and different platelet aggregation mechanisms across different parts of the body.…”

“…33 The fusion protein, when expressed and purified, showed the thrombolytic activity of Dsak, which specifically activates the fibrinolytic system. 33 Therefore, administration of somatostatin to prevent DVT after surgery may cause an adjustment between the aforementioned systems and different platelet aggregation mechanisms across different parts of the body. 18,34 At the very least, postoperative use of hemostatic agents is not a risk factor for thrombosis.…”