Development of Zika Virus E Variants for Pseudotyping Retroviral Vectors Targeting Glioblastoma Cells

Abstract

A fundamental idea for targeting glioblastoma cells is to exploit the neurotropic properties of Zika virus (ZIKV) through its two outer envelope proteins, prM and E. This study aimed to develop envelope glycoproteins for pseudotyping retroviral vectors that can be used for efficient tumor cell infection. Firstly, the retroviral vector pNLlucAM was packaged using wild-type ZIKV E to generate an E-HIVluc pseudotype. E-HIVluc infection rates for tumor cells were higher than those of normal prME pseudotyped particles and the traditionally used vesicular stomatitis virus G (VSV-G) pseudotypes, indicating that protein E alone was sufficient for the formation of infectious pseudotyped particles. Secondly, two envelope chimeras, E41.1 and E41.2, with the E wild-type transmembrane domain replaced by the gp41 transmembrane and cytoplasmic domains, were constructed; pNLlucAM or pNLgfpAM packaged with E41.1 or E41.2 constructs showed infectivity for tumor cells, with the highest rates observed for E41.2. This envelope construct can be used not only as a tool to further develop oncolytic pseudotyped viruses for therapy, but also as a new research tool to study changes in tumor cells after the transfer of genes that might have therapeutic potential.

Generation of Viral Particles with Brain Cell-Specific Tropism by Pseudotyping HIV-1 with the Zika Virus E Protein

“…They allow the study of oncogenic or oncolytic viruses, gene delivery, evaluation of targeted therapies, vaccine development and much more, ultimately contributing to a better understanding of cancer biology and the development of new cancer treatments. ZIKV is here used as an example that is of utmost importance in regard to brain cancer [ 16 ] but might also be of high relevance for other cancer types [ 14 ]. We have established this protocol for the development of ZIKV/HIV pseudotypes as a tool for virotherapy of brain tumors, especially glioblastoma.…”

“…Another aspect seems to be related to the presence of the ZIKV transmembrane domains of the prM protein. When prM is eliminated, ZIKV E alone can produce efficient amounts of pseudotypes [ 16 ]. When compared to VSV-G, the ZIKV E pseudotypes E2-HIV gfp produced significantly more GFP-positive foci than G-HIV gfp .…”

“…Some reports show different results, both increased [ 14 ] and decreased activity [ 20 ], when the TM region was exchanged for that of VSV-G. In contrast, good results were obtained with a chimera of ZIKV E and the TM region of gp41 [ 16 ]. However, it has been shown that a pseudotype, E2-HIVgfp, with brain tumor specificity can be produced that has a higher transduction efficiency compared to the commonly used VSV-G pseudotypes.…”

“…For protein E, there are reports of E pseudotyped viral vectors such as JEV/MuLV or JEV/HIV [ 12 , 13 ], but, especially for ZIKV, there are only a limited number of publications available describing the successful ZIKV/HIV pseudotype production [ 8 , 14 , 15 , 16 ]. In the first publication, it was demonstrated that the ZIKV prME complex can produce pseudotypes, but at a very low level [ 8 , 15 ].…”

“…One approach was that E was expressed using a standard protein expression vector including an exchange of the E transmembrane (TM) domain with the TM of VSV-G [ 14 ]. The second approach was to use the TM and cytoplasmic domain of HIV-1 gp41 as a membrane anchor for the E protein [ 16 ]. The third and more simple approach was to link the E protein to the TM domain present between capsid and prM, TM(C), leaving the normal E protein stem and anchor region intact ( Figure 2 ) [ 16 ].…”