Sindbis Virus-Pseudotyped Lentiviral Vectors Carrying VEGFR2-Specific Nanobody for Potential Transductional Targeting of Tumor Vasculature

Abstract

Introduction of selectivity/specificity into viral-based gene delivery systems, such as lentiviral vectors (LVs), is crucial in their systemic administration for cancer gene therapy. The pivotal role of tumor-associated endothelial cells (TAECs) in tumor angiogenesis and overexpression of vascular endothelial growth factor receptor-2 (VEGFR2 or KDR) in TAECs makes them a potent target in cancer treatment. Herein, we report the development of VEGFR2-targeted LVs pseudotyped with chimeric sindbis virus E2 glycoprotein (cSVE2s). For this purpose, either sequence of a VEGFR2-specific nanobody or its natural ligand (VEGF) was inserted into the binding site of sindbis virus E2 glycoprotein. In silico modeling data suggested that the inserted targeting motifs were exposed in the context of cSVE2s. Western blot analysis of LVs indicated the incorporation of cSVE2s into viral particles. Capture ELISA demonstrated the specificity/functionality of the incorporated cSVE2s. Transduction of 293/KDR (expressing VEGFR2) or 293T cells (negative control) by constructed LVs followed by fluorescent microscopy and flow cytometric analyses indicated selective transduction of 293/KDR cells (30 %) by both targeting motifs compared to 293T control cells (1-2 %). These results implied similar targeting properties of VEGFR2-specific nanobody compared to the VEGF and indicated the potential for transductional targeting of tumor vasculature by the nanobody displaying LVs.

MicroRNA-370 suppresses the retinal capillary endothelial cell growth by targeting KDR gene

“…The inhibition of KDR activities has been considered to be one of the potential promising targets for the prevention of neovascularization. Ahani et al reported that the nanobody carried by lentiviral vectors targeting the KDR could potentially reduce the neovascularization in tumor vasculature (22). Other authors have also reported various approaches to inhibit the biological activity of KDR thus resulting in the inhibition of angiogenesis (23,24).…”

Nanobodies: Next Generation of Cancer Diagnostics and Therapeutics

“…Nanobody-AAVs have shown success in targeting antigens such as CD38, ARTC2.2, and P2X7, but further in vivo studies are needed ( 138 ). Viral vectors have also shown potential for targeting tumor vasculature, and Ahani et al ( 139 ) developed anti-VEGFR2-LVs with comparable targeting to that of VEGF. Additionally, recombinant lambda (λ) bacteriophages have reported significant in vitro inhibition of HER2 + cell proliferation ( 140 ).…”

Towards Physiologically and Tightly Regulated Vectored Antibody Therapies

“…For example, antibodies targeting tissue-specific or tumor-specific markers (e.g., HER2) have been used to control vector tropism in vivo in breast tumors. Alternatively, vectors carrying nanobodies or antibodies direct against VEGFR2 were proven effective to respectively target tumor vasculature [102,104].…”