De Novo Computational Design for Development of a Peptide Ligand Oriented to VEGFR-3 with High Affinity and Long Circulation.

The overexpression of VEGFR-3 is correlated with a worse prognosis in lung cancer and has been regarded as a rational target for specific drug delivery. Here, VEGFR-3 homing peptide library was efficiently established by computational design. Strong fluorescent signals of selected peptides were observed in A549 cells, but much weaker in other cells. The positive immunostaining overlapped with VEGFR-3 confirmed high affinity and selectivity of one novel peptide (CP-7). In addition, cell uptake of FITC-CP-7 peptide was significantly blocked by coinjection of excess CP-7 peptide. After labeled with 131I, the profile of pharmacology and biodistribution could be traced in vivo. The 131I-radiolabeled CP-7 peptide conjugates were >85% stable in serum over 4 h and exhibited a specific uptake of 18.04 ± 2.04% ID/g at 0.5 h after injection to high VEGFR-3 expressing A549 tumor mice. More importantly, lower uptake concentration in heart (1.06 ± 0.15% ID/g) after 2 h demonstrated the safety of peptide in vivo. The high uptake in the kidneys revealed that renal clearance was the main route of 131I-CP-7 peptide elimination from the body. Lower accumulation of 131I-CP-7 peptide in VEGFR-3 negative HeLa tumor mice further indicated that CP-7 peptide exhibited a higher tumor-homing efficiency. These studies provided a straightforward analytical access to design and screen bioactive peptide based on protein structure and revealed that CP-7 peptide represented a promising homing peptide of VEGFR-3-positive cancer in vitro and in vivo which could be used as a novel target molecule to achieve efficient drug delivery.

An Integrative Folate-Based Metal Complex Nanotube as a Potent Antitumor Nanomedicine as Well as an Efficient Tumor-Targeted Drug Carrier.

Metal-organic complexes (MOCs) are emerging developing functional materials, the different categories of metal ions and organic biomolecules provide great possibilities for the morphologies, sizes, and properties of the products. Enlightened by the previous works of folate-nickel nanotubes (FA-Ni NTs), herein, a series of metal ions are tested to coordinate with folate (FA) by the solvothermal method, among which the folate-cobalt(II) complex is formed to be a scaffold for the nanotube with the length of 150-500 nm and inner diameter of 6-11 nm, while the other metal ions fail. In vitro experiments reveal that folate-cobalt nanotubes (FA-Co NTs) have excellent antitumor activity toward tumor cells with high expression levels of folate receptor (FR), whereas they show extremely low toxicity to normal cells. Furthermore, these kinds of NTs show better antitumor ability when the anticancer drug doxorubicin is encapsulated through cell surface receptor-mediated endocytosis. Moreover, we study the fundamental pharmacokinetic profiles and biodistribution of FA-Co NTs on mice and also prove its targeting capability to tumor tissues on tumor-bearing mice using the radioactive iodine-131 (131I) tracing method. FA-Co NTs can also markedly inhibit the growth of tumor with minimal side effects when administered individually in vivo. These findings will expand the research on FA based metal complex nanomaterials as a kind of potential antitumor nanomedicine as well as a targeted drug carrier.