Cancer-Specific Splicing Ribozyme Vector for Liver Cancer Therapy
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Solution Overview
Problem
Current cancer gene therapies face challenges in achieving high tissue specificity and therapeutic efficacy, often causing side effects due to low expression efficiency and toxicity to normal cells, particularly when targeting cancer-specific genes like hTERT.
Innovation Solution
A recombinant vector is developed comprising a tissue-specific promoter, a trans-splicing ribozyme targeting a cancer-specific gene, a splicing donor/splicing acceptor sequence, a woodchuck hepatitis virus posttranscriptional regulatory element, and a nucleic acid sequence recognizing microRNA-122a, which increases expression efficiency and reduces toxicity to normal tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a tissue-specific promoter is used to increase cancer tissue specificity, then the side effects on normal cells are reduced, but the therapeutic efficacy is lowered due to low expression efficiency
Solution Approach 1:
The patent combines multiple regulatory elements (tissue-specific promoter, WPRE, microRNA-122a target sequence) into a composite expression cassette that integrates the benefits of specificity and high expression efficiency, resolving the contradiction between reduced side effects and maintained therapeutic efficacy
Solution Approach 2:
The patent changes the expression level parameter by introducing WPRE and microRNA-122a target sequences, which significantly increase ribozyme expression in cancer cells while maintaining tissue specificity, thereby improving therapeutic efficacy without increasing side effects
2Productivity
If conventional gene therapy methods are used to target cancer cells, then therapeutic effects are achieved, but normal cells are also affected causing adverse side effects
Solution Approach 1:
The patent applies local quality by making the gene expression system responsive to local conditions in cancer cells through microRNA-122a target sequences, enabling selective expression only in cancer cells that lack or have reduced levels of microRNA-122a, thus achieving therapeutic effect without affecting normal cells
Solution Approach 2:
The patent uses microRNA-122a target sequences as an intermediary mechanism that mediates selective expression in cancer cells, allowing the therapeutic ribozyme to be activated only in the presence of cancer-specific molecular signatures while remaining inactive in normal cells
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The approach enhances cancer tissue-specific therapeutic effects while minimizing side effects by specifically targeting hepatocellular carcinoma cells, as demonstrated by increased ribozyme expression and cell death induction in cancer cells with reduced toxicity to normal cells.
Implementation Method 1
the group I intron ribozyme from Tetrahymena thermophila can perform trans-splicing reactions to link two separate transcripts in vitro as well as in bacterial cells and human cells
Implementation Method 2
a woodchuck hepatitis virus posttranscriptional regulatory element (WPRE) is linked to the 3' end of the ribozyme-target gene expression cassette
Implementation Method 3
a nucleic acid sequence recognizing a micro RNA-122a (microRNA-122a, miR-122a) is further linked to the 3' end of the WPRE
Data Source
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AI summary
The present invention relates to a recombination vector, a transformation cell into which the recombinant vector is introduced, a ribozyme expressed from the recombination vector, a prophylactic or therapeutic composition for liver cancer comprising the recombination vector and the ribozyme, and a therapeutic method for liver cancer using the composition, said recombination vector comprising: a tissue-specific promoter; and a ribozyme-target gene expression cassette comprising a trans-splicing ribozyme targeting a cancer-specific gene and a target gene connected to the 3' exon of the ribozyme, wherein a splicing donor/splicing acceptor sequence (SD/SA sequence) is connected to the 5' end of the ribozyme-target gene expression cassette, woodchuck hepatitis virus posttranscriptional regulatory element (WPRE) is connected to the 3' end of the ribozyme-target gene expression cassette, and a nucleic acid sequence recognizing a micro RNA-122a (microRNA-122a, miR-122a) is further connected to the 3' end of the WPRE.