Abstract 5791
Background
There is a great demand for improved oncolytic viruses that selectively replicate inside cancer cells while sparing normal tissues. Here we describe a novel oncolytic adenovirus, Ixovex, that obtains a cancer selective replication phenotype by modulating the level of expression of the different alternatively spliced E1B mRNA isoforms.
Methods
In our work to probe the function of the E1B proteins we generated a virus mutant, the Ixovex virus, in which the SA1 3’ splice acceptor site sequence CAG:GA was mutated to CgG:GA. This single nucleotide point mutation (genomic location 3216) changed aa 399 in the E1B-496R protein from an arginine (AGG) to a glycine (gGG). IxoVex was validated for its viral replication (TCID-50 assay) and cytotoxicity (MTS assay) in a panel of normal and cancer cell lines. Animal studies for anti-tumour efficacy studies were performed in nude mice.
Results
Ixovex is a recombinant adenovirus that carries a single point mutation in the E1B-93R 3’ splice acceptor site that results in an overexpression of the E1B-156R splice isoform. Further, the mutation resulted in a loss of E1B-496R (E1B-55K) protein expression and as a consequence a failure of Ixovex to efficiently degrade the p53 tumour suppressor protein. Ixovex significantly inhibited tumour growth and prolonged survival of mice in an immune-deficient lung carcinoma tumour model. In complementation experiments overexpression of E1B-156R was shown to increase the oncolytic index of both Ad5wt and ONYX-015. In contrast to prior art viruses of similar type, Ixovex includes a functional E3B region for better in vivo efficacy. Ixovex virus, throughout this study has been proven to be by far the superior virus in potency compared to ONYX-015.
Conclusions
The decrease in toxicity and the inhibition of replication in normal cells indicate an astounding safety profile of Ixovex. The observation that the ONYX-015 virus replicated better in normal cells compared to Ixovex is intriguing considering that the ONYX-015 virus carries a large deletion that removes the coding sequences and splice signals needed to express the E1B-496R, E1B-93R and E1B-156R proteins. Ixovex significantly inhibit tumour growth in a human lung carcinoma animal model and that ONYX-015 does not.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
IxoGen.
Disclosure
M. Anwar: Shareholder / Stockholder / Stock options: IxoGen. G. Alusi: Shareholder / Stockholder / Stock options: IxoGen. D. Oberg: Shareholder / Stockholder / Stock options: IxoGen.
Resources from the same session
2316 - A 3D co-culture platform of breast cancer and patient derived immune cells to analyse the response to chemotherapy and immunotherapies
Presenter: Diana Saraiva
Session: Poster Display session 3
Resources:
Abstract
4290 - Characterization of the mechanism of action and efficacy of MEN1611 (PA799), a novel PI3K inhibitor, in breast cancer preclinical models.
Presenter: Alessio Fiascarelli
Session: Poster Display session 3
Resources:
Abstract
2167 - Neat-1: culprit lnRNA tying PIG-C, MSLN, CD80 in TNBC
Presenter: Nada Hussein
Session: Poster Display session 3
Resources:
Abstract
1829 - A novel RAF/MEK inhibitor CH5126766 in phase 1 clinical trial has an effectiveness in the combination with eribulin for the treatment of triple negative breast cancer
Presenter: Hisako Ono
Session: Poster Display session 3
Resources:
Abstract
4357 - Identification of a stemness-related gene panel associated with BET inhibition in triple negative breast cancer
Presenter: Eva Galan-Moya
Session: Poster Display session 3
Resources:
Abstract
5163 - Preclinical Evaluation targeting both IGF1R and IR in Triple Negative Breast Cancer
Presenter: Alex Eustace
Session: Poster Display session 3
Resources:
Abstract
832 - Monospecific antibody targeting of CDH11 inhibits epithelial-to-mesenchymal transition and represses cancer stem cell-like phenotype by up-regulating miR-335 in metastatic breast cancer, in vitro and in vivo.
Presenter: Jia-Hong Chen
Session: Poster Display session 3
Resources:
Abstract
3781 - Pharmacological screening with Chk1 inhibitors identify synergistic agents to overcome resistance to platinums in basal breast and ovarian cancer
Presenter: Ana Lucia Sanabria
Session: Poster Display session 3
Resources:
Abstract
3275 - Comparison of 11 circulating miRNAs and CA125 kinetics in ovarian cancer during first line treatment: data from the randomized CHIVA trial (a GINECO-GCIG study)
Presenter: Patrick Robelin
Session: Poster Display session 3
Resources:
Abstract
3391 - Inhibiting Ehmt2 and Ezh2 histone methyltransferases alters the immune microenvironment in a Trp53-/- murine ovarian cancer model
Presenter: Pavlina Spiliopoulou
Session: Poster Display session 3
Resources:
Abstract