Adeno-associated virus (AAV) serotypes 2, 4 and 5 display similar transduction profiles and penetrate solid tumor tissue in models of human glioma.
BACKGROUND
Adeno-associated viral (AAV) vectors are potent delivery vehicles for gene transfer strategies directed at the central nervous system (CNS), muscle and liver. However, comparatively few studies have described AAV-mediated gene transfer to tumor tissues. We have previously demonstrated that while AAV2 and Adenoviral (Ad) 5 vectors have similar broad host ranges in tumor-derived cell lines, AAV2 was able to penetrate human glioblastoma biopsy spheroids and xenografts more efficiently than Ad 5 vectors. These results suggested that AAV vectors could be suitable for therapeutic gene delivery to solid tumor tissue. In the present work, the transduction efficacy of AAV serotypes 4 and 5 were compared to AAV2, both in vitro and in intracranial GBM xenografts derived from patient biopsies implanted into nude rats.


METHODS
AAV vector serotypes 2, 4, and 5 containing either the green fluorescent protein (GFP) or the bacterial beta-galactosidase (lacZ) reporter gene were added to five different human glioma cell lines, to multicellular spheroids generated from glioblastoma patient biopsies, and to spheroids xenografted intracranially in nude rats. Transduction efficiency was assessed by fluorescence imaging, histochemistry, immunohistochemistry and flow cytometry.


RESULTS
While all three AAV serotypes were able to transduce the glioma cell lines when added individually or when they were administered in concert, AAV2 transduced the glioma cells most effectively compared to AAV4 or AAV5. Upon infecting glioblastoma spheroids in vitro, all three AAV serotypes efficiently transduced cells located at the surface as well as within deeper layers of the spheroids. In addition, similarly to what was observed for AAV2 16, both AAV4 and AAV5 were able to transduce human glioblastoma xenografts implanted intracranially.


CONCLUSIONS
In addition to the widely used AAV2 serotype, AAV4 and AAV5 serotypes may also be used to transduce biologically diverse glioma cell lines. They also penetrate and transduce solid human tumor tissue derived from patient biopsies. Therefore, the data presented here provide a proof of principle for developing AAV4 and AAV5 as treatment vehicles for human malignant gliomas.
Thorsen
Frits
F
Department of Biomedicine, Section of Anatomy and Cell Biology, University of Bergen, and Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway. frits.thorsen@biomed.uib.no
Afione
Sandra
S
Huszthy
Peter C
PC
Tysnes
Berit B
BB
Svendsen
Agnete
A
Bjerkvig
Rolf
R
Kotin
Robert M
RM
Lønning
Per Eystein
PE
Hoover
Frank
F
D000818:Animals; D045744:Cell Line, Tumor; D000229:Dependovirus / Q000145:classification* / Q000235:genetics*; D005260:Female; D017930:Genes, Reporter; D015316:Genetic Therapy / Q000379:methods*; D005909:Glioblastoma / Q000235:genetics / Q000473:pathology / Q000628:therapy; D005910:Glioma / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D007763:Lac Operon; D008297:Male; D009368:Neoplasm Transplantation; D051381:Rats; D011923:Rats, Nude; D012703:Serotyping; D018874:Spheroids, Cellular; D014161:Transduction, Genetic; D014183:Transplantation, Heterologous
D049452:Green Fluorescent Proteins