A tropism-transformed Oncolytic Adenovirus with Dual Capsid Modifications for enhanced Glioblastoma Therapy

Abstract

Glioblastoma, the most common human brain tumor, is highly invasive and difficult to cure using conventional cancer therapies. As an alternative, adenovirus-mediated virotherapies represent a popular and maturing technology. However, the cell surface coxsackievirus and adenovirus receptor (CAR)-dependent infection mechanism limits the infectivity and oncolytic effects of Adenovirus type 5. To address this limitation, in this study we aimed to develop a novel oncolytic adenovirus for enhanced infectivity and therapeutic efficacy toward glioblastoma. We developed a novel genetically modified oncolytic adenovirus vector with dual capsid modifications to facilitate infection and specific cytotoxicity toward glioma cells. Modification of the adenoviral capsid proteins involved the incorporation of a synthetic leucine zipper-like dimerization domain into the capsid protein IX (pIX) of human adenovirus serotype 5 (Ad5) and the exchange of the fiber knob from Ad37. The virus infection mechanism and anti-tumor efficacy of modified vectors were evaluated in both in vitro (cell) and in vivo (mouse) models. Ad37-knob exchange efficiently promoted the virus infection and replication-induced glioma cell lysis by oncolytic Ad5. We also found that gene therapy mediated by the dual-modified oncolytic Ad5 vector coupled with the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) exhibited significantly enhanced anti-tumor efficacy in vitro and in vivo. This genetically modified oncolytic adenovirus provides a promising vector for future use in glioblastoma gene-viral-based therapies.

Cell Membrane-Coated Oncolytic Adenovirus for Targeted Treatment of Glioblastoma

“…After confirming that the cell membrane-coated oncolytic adenovirus can improve the infectivity to and targeting of glioma, we wanted to further enhance the tumor-killing activity of this strategy. Our group recently constructed a dual-modified oncolytic Ad5 vector (A4/k37) coupled with the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) that exhibited significantly enhanced antitumor efficacy through enhancing infectivity and apoptotic activity to GBM cells . Modification of the adenoviral capsid proteins involved the incorporation of a synthetic leucine zipper-like dimerization domain into capsid protein IX (pIX) of Ad5 and the exchange of the fiber knob from Ad37.…”

“…Our group recently constructed a dualmodified oncolytic Ad5 vector (A4/k37) coupled with the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) that exhibited significantly enhanced antitumor efficacy through enhancing infectivity and apoptotic activity to GBM cells. 12 Modification of the adenoviral capsid proteins involved the incorporation of a synthetic leucine zipper-like dimerization domain into capsid protein IX (pIX) of Ad5 and the exchange of the fiber knob from Ad37. The design and modification strategy is shown in Figure 4A.…”

“…An oncolytic adenovirus based on adenovirus serotype 5 (Ad5), also known as conditionally replicating Ad5 (CRAd5), constitutes a popular alternative approach commonly deployed for cancer therapeutic studies, and many studies have relied on genetic modification of CRAd5 to enhance its ability to infect and kill tumor cells. , To develop an oncolytic adenovirus to enhance the therapeutic efficacy for GBM, we previously designed a novel genetically modified oncolytic adenovirus vector (A4/k37) with dual-capsid modifications and proved it can facilitate infection and specific cytotoxicity toward glioma cells . However, further studies revealed that A4/k37 could not cross the BBB upon intravenous injection in xenograft tumor mouse models (unpublished).…”

“…10,11 To develop an oncolytic adenovirus to enhance the therapeutic efficacy for GBM, we previously designed a novel genetically modified oncolytic adenovirus vector (A4/k37) with dual-capsid modifications and proved it can facilitate infection and specific cytotoxicity toward glioma cells. 12 However, further studies revealed that A4/k37 could not cross the BBB upon intravenous injection in xenograft tumor mouse models (unpublished).…”

In vitro functional genetic modification of canine adenovirus type 2 genome by CRISPR/Cas9

“…These include nearly ubiquitous tropism, which makes targeted infection difficult, significant immunogenicity, and high levels of preexisting exposure in many populations. [2][3][4] Non-human adenoviruses have been gaining significant attention in clinical applications due to their potential to bypass some of the clinical disadvantages provided by human adenoviruses. Canine adenovirus type 2 (CAV2), an adenovirus derived from the dog, has been advocated as a vector for both canine and human applications and, in human patients, may bypass the disadvantages of pre-existing humoral immunity and stimulation of memory cytotoxic lymphocytes (CTLs).…”