Construction of novel chimeric proteins through the truncation of SEC2 and Sak from Staphylococcus aureus

Abstract

It is an 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. Therefore, the construction of a bifunctional chimeric protein for the treatment of cancer, complicated with thrombosis, is of great significance. Utilizing the superantigenic activity of staphylococcal enterotoxin C2 (SEC2) and the thrombolytic activity of staphylokinase (Sak), Sak-linker-SEC2 and SEC2-linker-Sak were constructed which had good anti-tumor and thrombolytic activities at the same time. Due to the intrinsic emetic activity of SEC2 and high molecular weight (MW) of chimeric proteins (44 kDa), their clinical applications will be restricted. In this study, novel chimeric proteins including ΔSEC2–ΔSak and ΔSak–ΔSEC2 were constructed through the truncation of SEC2 and Sak without 9-Ala linker and His-tag. Compared with the former, both the truncated proteins preserved nearly the same anti-tumor and thrombolytic activities. In addition, their MWs were only 29 kDa and their immunoreactivities were slightly lower than that of Sak-linker-SEC2 and SEC2-linker-Sak, respectively. Therefore, the novel chimeric proteins possessed merits and characteristics, such as low MS, low immunogenicity, and difunctionality which the former had not. It will be of great interest if the above-mentioned proteins can be used to cure Trousseau syndrome in clinic.

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

“…To obtain novel fusion proteins that would target tumor cells, DNA sequence encoding octreotide gene ( oct ) was inserted into pET28a –Δsec2–Δsak and pET28a– Δsak–Δsec2 using PCR. DNA sequencing demonstrated that oct was correctly inserted into pET28a –Δsec2–Δsak and pET28a– Δsak–Δsec2 , resulting in plasmids pET28a– oct–Δsec2–Δsak and pET28a– oct – Δsak–Δsec2 , respectively.…”

“…DNA sequence encoding to octreotide gene was amplified using primer OS3 and OS4 (Table ) and inserted into Eco RI and Xho I sites of plasmid pET‐28a –Δsec2–Δsak and pET‐28a –Δsak–Δsec2 , resulting in pET‐28a –oct–Δsec2–Δsak and pET‐28a –oct–Δsak–Δsec2 . Plasmids were, respectively, transformed into E. coli BL21 (DE3).…”

“…This strategy can provide a new way to treat cancer. In this study, DNA sequence encoding octreotide gene was inserted into plasmid pET‐28a –Δsec2‐Δsak and pET‐28a –Δsak–Δsec2 , so as to obtain novel fusion proteins to study the dual effects of bridging tumor cells and activating T‐cell proliferation. According to our results, fusion proteins possessed abilities of targeting tumor therapy.…”

Effect of Highly Ag-glutinative Staphylococcin Combined with α -Hemihydrate Calcium Sulfate on Tendine-Bone Healing in Cruciate Ligament Reconstruction

“…The idea of highly ag-glutinative Staphylococcin was developed by the pathological mechanism of osteomyelitis, and a sterile clear transparent or slightly yellow liquid substance was puri ed from the secretion of highly ag-glutinative Staphylococcin, which belongs to the national Class A new drug [(94) Wei Medicine Zheng Zi S-08]. It has been found in clinical work that this drug can effectively promote fracture healing and ingrowth [29] .S.aureus, rich in staphylococcus aureus enterotoxin C (SEC), plasma free coagulase , a variety of active substances such as protein, polypeptide and amino acid [30] .Soviet scholars MOB OB и H et al…”

Development of Staphylococcus aureus-derived skin cancer therapeutics

“…SEB is reported to reduce HCT116 cell viability, though cell death was not observed [507]. A chimeric protein SEC 2-linker-Sak was also shown to exert anti-tumour and thrombolytic activity in tumour thrombus [508]. The use of S. aureus Hla delivered using live E. coli vector has been explored in mouse model breast cancer [509,510].…”