Abstract
BackgroundProteinaceous bioactive substances and pharmaceuticals are most conveniently administered orally. However, the facing problems are the side effects of proteolytic degradation and denaturation in the gastrointestinal tract. In recent years, lactic acid bacteria (LAB) have been verified to be a promising delivery vector for susceptible functional proteins and drugs. KiSS-1 peptide, a cancer suppressor, plays a critical role in inhibiting cancer metastasis and its activity has been confirmed by direct administration. However, whether this peptide can be functionally expressed in LAB and exert activity on cancer cells, thus providing a potential alternative administration manner in the future, has not been demonstrated.ResultsA recombinant Lactococcus lactis strain NZ9000-401-kiss1 harboring a plasmid containing the gene of the tumor metastasis-inhibiting peptide KiSS1 was constructed. After optimization of the nisin induction conditions, the recombinant strain efficiently secreted KiSS1 with a maximum detectable amount of 27.9 μg/ml in Dulbecco’s Modified Eagle medium. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide and would healing assays, respectively, indicated that the secreted KiSS1 peptide remarkably inhibited HT-29 cell proliferation and migration. Furthermore, the expressed KiSS1 was shown to induce HT-29 cell morphological changes, apoptosis and reduce the expression of matrix metalloproteinase 9 (MMP-9) at both mRNA and protein levels.ConclusionsA recombinant L. lactis NZ9000-401-kiss1 successfully expressing the human kiss1 was constructed. The secreted KiSS1 peptide inhibited human HT-29 cells’ proliferation and migration probably by invoking, or mediating the cell-apoptosis pathway and by down regulating MMP-9 expression, respectively. Our results suggest that L. lactis is an ideal cell factory for secretory expression of tumor metastasis-inhibiting peptide KiSS1, and the KiSS1-producing L. lactis strain may serve as a new tool for cancer therapy in the future.
Highlights
Proteinaceous bioactive substances and pharmaceuticals are most conveniently administered orally
Cloning and expression of kiss1 in L. lactis NZ9000 The whole kiss1 gene in length of 417 bp was amplified from the complementary DNA (cDNA) of human placenta by PCR and cloned into the nisin-induction vector pNZ401 which contained the Usp45 signal peptide and LEISSTCDA [29] synthetic propeptide (Fig. 1a)
The resulting recombinant plasmids pNZ401 and pNZ401-kiss1 were transformed into L. lactis NZ9000, respectively
Summary
Proteinaceous bioactive substances and pharmaceuticals are most conveniently administered orally. Lactic acid bacteria (LAB) have been verified to be a promising delivery vector for susceptible functional proteins and drugs. KiSS-1 peptide, a cancer suppressor, plays a critical role in inhibiting cancer metastasis and its activity has been confirmed by direct administration. Whether this peptide can be functionally expressed in LAB and exert activity on cancer cells, providing a potential alternative administration manner in the future, has not been demonstrated. Oral administration employing delivery systems like hydrogels, nanoparticles, microspheres, and lipid-based systems is a convenient way of delivering drugs. Tumor-targeted reagents, anticancer drugs, and non-invasive insulin- and vaccine-delivery systems can be developed based on live L. lactis [14, 15]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call