Recombinant Adenovirus E1B-156R Isoform Modulation
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Solution Overview
Problem
Current oncolytic adenoviruses, such as ONYX-015, face challenges in achieving enhanced oncolytic ability and stability, with issues like compromised viral reproduction and genetic instability due to large deletions in the E1B region, which affect their therapeutic efficacy in cancer treatment.
Innovation Solution
Modulating the levels and types of E1B gene splice isoforms, particularly increasing the proportion of E1B-156R relative to wild-type levels, to enhance oncolytic activity while maintaining safety by inhibiting replication in non-neoplastic cells and allowing selective replication in cancer cells, thereby improving the cancer selection index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large deletions are made in the E1B region to create oncolytic adenoviruses, then selective replication in cancer cells is achieved, but viral reproduction ability and genetic stability are compromised
Solution Approach 1:
The invention changes the splicing parameters of the E1B gene to alter the proportion of different splice isoforms (E1B-55K, E1B-19K, E1B-93R, E1B-156R). By modulating splicing patterns rather than making large deletions, the virus maintains genetic stability while achieving selective replication in p53-deficient cancer cells. This parameter change approach resolves the contradiction by finding an alternative mechanism that doesn't compromise viral reproduction.
Solution Approach 2:
The invention segments the E1B gene expression into multiple splice isoforms with different functions. Instead of a single large deletion, the virus produces a profile of E1B proteins where E1B-55K and E1B-19K handle p53 interaction, while E1B-93R and E1B-156R handle other essential functions. This segmentation allows selective pressure on cancer cells while maintaining overall viral reproduction capability.
2Reliability
If E1B-496R protein is mutated to remove p53 binding interactions, then oncolytic selectivity is improved, but other essential functions of E1B-496R are compromised
Solution Approach 1:
The invention changes the splicing parameters to produce different proportions of E1B isoforms. By increasing E1B-156R and E1B-93R while maintaining or reducing E1B-55K, the virus achieves oncolytic selectivity through altered p53 interaction dynamics while compensating for loss of other E1B-496R functions through the alternative isoforms.
Solution Approach 2:
The invention makes the E1B gene product multi-functional by producing multiple splice isoforms from a single gene. Each isoform (E1B-55K, E1B-19K, E1B-93R, E1B-156R) can perform different functions, allowing the virus to maintain cytoplasmic accumulation of late mRNAs and other essential functions even when E1B-496R p53 binding is reduced or eliminated.
3Reliability
If the proportion of E1B-156R isoform is increased, then oncolytic index and safety profile are improved, but the complexity of viral gene regulation increases
Solution Approach 1:
The invention changes splicing parameters (splice site sequences, splicing regulatory elements) to naturally increase E1B-156R proportion. This parameter change achieves improved safety profile through enhanced oncolytic selectivity while using the virus's existing splicing machinery, thereby avoiding significant increases in regulatory complexity.
Data Source
AI summary
The invention relates to a recombinant adenovirus that has an oncolytic effect in a cancer cell. By modulating the level and type of splice isoforms of the E1B gene product, expressed from the E1B gene, the oncolytic activity of such viruses can be enhanced. The invention provides a recombinant adenovirus in which the proportion of the E1B-156R isoform is increased relative to wild-type levels. Such a recombinant adenovirus may selectivity replicate in cancer cells, thereby killing cancer cells whilst sparing normal cells.