A novel bicistronic high-capacity gutless adenovirus vector that drives constitutive expression of herpes simplex virus type 1 thymidine kinase and tet-inducible expression of Flt3L for glioma therapeutics.
Glioblastoma multiforme (GBM) is a deadly primary brain tumor. Conditional cytotoxic/immune-stimulatory gene therapy (Ad-TK and Ad-Flt3L) elicits tumor regression and immunological memory in rodent GBM models. Since the majority of patients enrolled in clinical trials would exhibit adenovirus immunity, which could curtail transgene expression and therapeutic efficacy, we used high-capacity adenovirus vectors (HC-Ads) as a gene delivery platform. Herein, we describe for the first time a novel bicistronic HC-Ad driving constitutive expression of herpes simplex virus type 1 thymidine kinase (HSV1-TK) and inducible Tet-mediated expression of Flt3L within a single-vector platform. We achieved anti-GBM therapeutic efficacy with no overt toxicities using this bicistronic HC-Ad even in the presence of systemic Ad immunity. The bicistronic HC-Ad-TK/TetOn-Flt3L was delivered into intracranial gliomas in rats. Survival, vector biodistribution, neuropathology, systemic toxicity, and neurobehavioral deficits were assessed for up to 1 year posttreatment. Therapeutic efficacy was also assessed in animals preimmunized against Ads. We demonstrate therapeutic efficacy, with vector genomes being restricted to the brain injection site and an absence of overt toxicities. Importantly, antiadenoviral immunity did not inhibit therapeutic efficacy. These data represent the first report of a bicistronic vector platform driving the expression of two therapeutic transgenes, i.e., constitutive HSV1-TK and inducible Flt3L genes. Further, our data demonstrate no promoter interference and optimum gene delivery and expression from within this single-vector platform. Analysis of the efficacy, safety, and toxicity of this bicistronic HC-Ad vector in an animal model of GBM strongly supports further preclinical testing and downstream process development of HC-Ad-TK/TetOn-Flt3L for a future phase I clinical trial for GBM.
Puntel
Mariana
M
Gene Therapeutics Research Institute, Cedars-Sinai Medical Center/UCLA, 8700 Beverly Blvd., Davis Building Research Pavilion, Room 5090, Los Angeles, CA 90048, USA.
Muhammad
A K M G
AK
Candolfi
Marianela
M
Salem
Alireza
A
Yagiz
Kader
K
Farrokhi
Catherine
C
Kroeger
Kurt M
KM
Xiong
Weidong
W
Curtin
James F
JF
Liu
Chunyan
C
Bondale
Niyati S
NS
Lerner
Jonathan
J
Pechnick
Robert N
RN
Palmer
Donna
D
Ng
Philip
P
Lowenstein
Pedro R
PR
Castro
Maria G
MG
D000256:Adenoviridae / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D005910:Glioma / Q000235:genetics* / Q000378:metabolism / Q000628:therapy*; D018259:Herpesvirus 1, Human / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D051381:Rats; D011917:Rats, Inbred Lew; D013937:Thymidine Kinase / Q000235:genetics / Q000378:metabolism / Q000627:therapeutic use*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism / Q000627:therapeutic use*; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics / Q000378:metabolism / Q000627:therapeutic use*
D014764:Viral Proteins; D013937:Thymidine Kinase; C497970:FLT3 protein, human; D051941:fms-Like Tyrosine Kinase 3