Improved Adeno-associated Viral Gene Transfer to Murine Glioma

Abstract

Glioblastoma (GBM) is a deadly primary brain tumor. Current treatment, consisting of surgical removal of the tumor mass followed by chemotherapy and/or radiotherapy, does not significantly prolong survival. Gene therapies for GBM are being developed in clinical trials, for example using adenoviral vectors. While adeno-associated virus (AAV) represents an alternative vector system, limited gene transfer to glioma cells has hampered its use. Here, we evaluated newly emerged variants of AAV capsid for gene delivery to murine glioma. We tested a mutant AAV2 capsid devoid of 3 surface-exposed tyrosine residues, AAV2 (Y444-500-730F), and a “shuffed” capsid (ShH19, containing sequences from several serotypes) that had previously been selected for enhanced glial gene delivery. AAV2 (Y-F) and ShH19 showed improved transduction of murine glioma GL261 cells in vitro by 2- to 6-fold, respectively, over AAV2. While AAV2 gene transfer to GL261 cells in established tumors in brains of syngeneic mice was undetectable, intratumoral injection of AAV2 (Y-F) or ShH19 resulted in local transduction of approximately 10% of tumor cells. In addition, gene transfer to neurons adjacent to the tumor was observed, while microglia were rarely transduced. Use of self-complementary vectors further increased transduction of glioma cells. Together, the data demonstrate the potential for improved AAV-based gene therapy for glioma using recently developed capsid variants.

Gene therapy in glioblastoma multiforme: Can it be a role changer?

“…Long-lasting, stable, efficient, and non-toxic gene delivery, enabling the transduction of various target cells, establish AAV as a robust and successful viral vector [ 91 ]. In recent years, targeting GBM via AAV has gained widespread attention and demonstrated success in preclinical studies [ 92 ]. The discovery of AAV9 in 2009, followed by the emergence of rAAVrh.8 and rAAVrh.10 in 2014, heralded a revolution in the treatment of CNS diseases through the utilization of AAV vectors.…”

Current Approaches for Glioma Gene Therapy and Virotherapy

“…It was reported that a single intracranial injection of AAV encoding human interferon (IFN)-β in human and murine GBM models increases tumor cell death and promotes long-term survival (GuhaSarkar et al, 2017 ). Many researchers have developed high-efficiency AAV for GBM cells, by selection in culture of a chimeric AAV capsid library generated by DNA shuffling of different cap genes, with several different AAV serotypes (Maguire et al, 2010 ; Zolotukhin et al, 2013 ). Despite of the many advantages of this vector, at the moment they are not being evaluated in clinical trials; this should be expected soon.…”

Adeno‐associated virus (AAV)-based gene therapy for glioblastoma

“…AAV has been used to treat experimental GBM model for decades because of their stable and persistent expression of anti-tumor agents in transduced cells [ 53 ]. After the first discovery that AAV-encoded tumor suppressor genes could effectively inhibit the growth of GBM cell lines in vitro, AAV emerged as an effective delivery tool for the treatment of experimental GBM model [ 54 ].…”