AXL receptor is required for Zika virus strain MR-766 infection in human glioblastoma cell lines
Samuel D Zwernik1, Beau H Adams1, Daniel A Raymond1
1Advocate Aurora Research Institute, Advocate Aurora Health, Milwaukee, WI 53233, USA.
Abstract:
Recent reports have shown that Zika virus (ZIKV) has oncolytic potential against human glioblastoma (GBM); however, the mechanisms underlying its tropism and cell entry are not completely understood. The receptor tyrosine kinase AXL has been identified as an entry receptor for ZIKV in a cell-type-specific manner. Interestingly, AXL is frequently overexpressed in GBM patients. Using commercially available GBM cell lines, we first show that cells expressing AXL are permissive for ZIKV infection, while cells that do not express AXL are not. Furthermore, inhibition of AXL kinase using R428 and antibody blockade of AXL receptor strongly attenuated virus entry in GBM cell lines. Additionally, CRISPR knockout of the AXL gene in GBM cell lines completely abolished ZIKV infection, significantly inhibited viral replication, and significantly reduced apoptosis compared with parental lines. Lastly, introduction of AXL receptor into non-expressing cell lines renders the cells susceptible to ZIKV infection. Together, these findings demonstrate that ZIKV entry into GBM cells in vitro is mediated by the AXL receptor and that following cell entry, productive infection is cytotoxic. Thus, ZIKV is a potential oncolytic virus for GBM.
Insights
Zika virus (ZIKV) shows oncolytic potential against glioblastoma (GBM). The AXL receptor is crucial for ZIKV entry into GBM cells, making it a promising target for oncolytic virotherapy.
Area of Science:
- Virology
- Oncology
- Molecular Biology
Background:
- Zika virus (ZIKV) exhibits oncolytic potential against human glioblastoma (GBM).
- Mechanisms of ZIKV tropism and cell entry into GBM remain incompletely understood.
- The receptor tyrosine kinase AXL is implicated as a cell-type-specific entry receptor for ZIKV and is often overexpressed in GBM.
Purpose of the Study:
- To elucidate the role of the AXL receptor in ZIKV entry into GBM cells.
- To investigate the potential of ZIKV as an oncolytic agent for GBM treatment.
Main Methods:
- Utilized commercially available GBM cell lines with varying AXL expression levels.
- Assessed ZIKV permissiveness in AXL-expressing versus non-expressing cells.
- Employed AXL kinase inhibitors (R428) and antibody blockade to impede virus entry.
- Performed CRISPR-Cas9 gene editing to knockout AXL in GBM cells.
- Introduced AXL receptor into non-expressing cell lines to evaluate ZIKV susceptibility.
Main Results:
- GBM cells expressing AXL were permissive to ZIKV infection, while AXL-negative cells were resistant.
- Inhibition of AXL kinase activity and receptor blockade significantly reduced ZIKV entry.
- CRISPR-mediated AXL knockout abolished ZIKV infection, inhibited viral replication, and reduced apoptosis.
- Reconstitution of AXL in non-expressing cells rendered them susceptible to ZIKV infection.
Conclusions:
- Zika virus entry into glioblastoma cells *in vitro* is critically mediated by the AXL receptor.
- Productive ZIKV infection following AXL-mediated entry is cytotoxic to GBM cells.
- ZIKV demonstrates significant potential as an oncolytic virus therapy for glioblastoma.
