Enhanced Expression of Bioactive Recombinant VEGF-111 with Insertion of Intronic Sequence in Mammalian Cell Lines

Echinacoside regulates PI3K/AKT/HIF-1α/VEGF cross signaling axis in proliferation and apoptosis of breast cancer

CONTEXT

Echinacoside (ECH) is a natural anti-cancer compound and is of great value in cancer treatment. However, the mechanism underlying this effect on breast cancer (BC) was unclear.

OBJECTIVE

To explore the mechanism of ECH treating BC by network pharmacology and experimental validation.

MATERIALS & METHODS

Several databases were searched to screen potential targets of ECH and obtain information on targets related to BC. STRING was applied to construct a Protein-protein interaction (PPI) network. DAVID was applied for Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Gene Expression Profiling Interactive Analysis (GEPIA) was searched for the relationship between the expression profile and overall survival of major targets in normal breast and BC tissues. Finally, the results of network pharmacology analysis were validated by experiments.

RESULTS

Seventeen targets of ECH overlapped with targets in BC. Ten hub targets were determined through PPI. By GO and KEGG analysis 15 entries and 25 pathways were obtained, in which phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), hypoxia inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) played greater roles. Validation of key targets in the GEPIA database showed that PIK3R1 and PIK3CD remained consistent with the results of the study. Experiments in vitro showed ECH inhibited proliferation, induced apoptosis and reduced mRNA levels and protein expression of PI3K, AKT, hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor A (VEGFA) in MCF-7 cells. Furthermore, experiments in vivo revealed that ECH significantly reduced tumor growth, promoted apoptosis and decreased the related mRNA levels and protein expression, suggesting ECH works on BC by regulating PI3K/AKT/HIF-1α/VEGF signaling pathway.

DISCUSSION & CONCLUSION

In summary, ECH played an important role in anti-BC by regulating PI3K/AKT/HIF-1α/VEGF signaling pathway. Furthermore, ECH had multi-target and multi-pathway effects, which may be a promising natural compound for treating BC.

In Vitro Angiogenic Properties of Plasmid DNA Encoding SDF-1α and VEGF165 Genes

The stromal-derived factor-1 alpha (SDF-1α) and vascular endothelial growth factor (VEGF) play an important role in angiogenesis and exert a significant trophic function. SDF-1α is a chemoattractant for endothelial progenitor cells derived from bone marrow and promotes new blood vessel formation. VEGF regulates all types of vascular growth, stimulates angiogenesis, and is involved in the induction of lymphangiogenesis. The possibility of using these growth factors for regenerative medicine is currently under investigation. The angiogenic potential of a pBud-SDF-1α-VEGF165 bicistronic plasmid construct which simultaneously encodes VEGF165 and SDF-1α genes cDNA was evaluated in this study. The conditioned medium collected from HEK293T cells transfected with the pBud-SDF-1α-VEGF165 plasmid was shown to stimulate the formation of capillary-like structures by human umbilical vein-derived endothelial cells (HUVEC) on Matrigel and to increase the proliferative activity of these cells in vitro. Thus, the pBud-SDF-1α-VEGF165 plasmid exhibits angiogenic properties in cell cultures in vitro. As interest in the development of non-viral techniques for regenerative medicine increases, this plasmid which simultaneously expresses VEGF165 and SDF-1α may provide a platform for advanced methods of stimulating therapeutic angiogenesis.

Vector and Cell Line Engineering Technologies Toward Recombinant Protein Expression in Mammalian Cell Lines

The rapid growth of global biopharmaceutical market in the recent years has been a good indication of its significance in biotechnology industry. During a long period of time in recombinant protein production from 1980s, optimizations in both upstream and downstream processes were launched. In this regard, one of the most promising strategies is expression vector engineering technology based on incorporation of DNA opening elements found in the chromatin border regions of vectors as well as targeting gene integration. Along with these approaches, cell line engineering has revealed convenient outcomes in isolating high-producing clones. According to the fact that more than 50% of the approved therapeutic proteins is being manufactured in mammalian cell lines, in this review, we focus on several approaches and developments in vector and cell line engineering technologies in mammalian cell culture.