Nanobody-functionalized liposomal doxorubicin: A novel strategy for angiogenesis suppression via VEGFR2 targeting.

Abstract

Introduction: Doxorubicin (DOX) is a widely used first-line treatment for various cancers but causes toxicity. Targeted drug delivery systems, particularly DOX-encapsulated liposomes, show clinical success and lower toxicity. The abnormal angiogenesis in high-grade tumors, making it crucial to develop strategies that target this process in conjunction with chemotherapy. This study presents an innovative formulation of anti-VEGFR2-functionalized liposomal DOX, designed to reduce systemic drug release, enhance drug release and bioavailability at tumor sites, and reducing adverse effects, representing a promising advancement in targeted cancer therapy.

Methods: Liposome formulations including liposome (Lip), DOX loaded liposome (Lip-DOX), anti VEGFR2 Nanobody-conjugated liposome (Lip-Nb), and anti VEGFR2 Nanobody- conjugated DOX-loaded liposome (Lip-DOX-Nb) were prepared by film hydration method and then fully characterized. The cellular uptake of these nanocarriers were assessed by flow cytometry analysis in human umbilical vein endothelial cells (HUVECs). Further, the ability of the different liposomal formulations to suppress angiogenesis were assessed by performing tube formation assay on HUVECs. In addition, the inhibitory impact of low dose consumption of the formulations to inhibit the migratory capacity of glioma cells were assessed by scratch migration assay on U87 cells.

Results: The prepared liposomal formulations displayed optimal size range of 120-131 nm, with slightly negative charge about -2.4 mv, spherical morphology and effective encapsulation of about 91% of the total DOX and high conjugation efficiency of about 87% of total anti VEGFR2 Nb that are acceptable for nano sized targeted drug delivery systems. In vitro experiments; flow cytometry results verified cellular uptake of DOX loaded liposomes to HUVEC cell line and more cellular uptake was observed for Lip-DOX-Nb liposomes demonstrated that the anti-VEGFR2-conjugated liposomes enhance cellular uptake. Lip-DOX-Nb liposomes also showed more cytotoxicity effect against VEGFR2-positive HUVEC cells in compare with non-conjugated liposomes; effectively induced apoptosis to HUVEC cells and reduced the migratory capacity on U87 cancer cells. Analysis of the treated cells using DHM revealed that Lip-DOX-Nb enhanced nuclear integrity of U87 cancer cells while inducing cell death.

Conclusion: This designed drug delivery system worked as strong anticancer and angiogenesis suppression agent ex-vitro angiogenesis model via VEGFR2 targeting.