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A tumor specific single chain antibody dependent gene expression system
M N Mary1, C Venot, C Caron de Fromentel
1Gene Medicine Department, Rhône-Poulenc Rorer S.A., Vitry-sur-Seine, France.
Abstract:
The design of conditional gene expression systems restricted to given tissues or cellular types is an important issue of gene therapy. Systems based on the targeting of molecules characteristic of the pathological state of tissues would be of interest. We have developed a synthetic transcription factor by fusing a single chain antibody (scFv) directed against p53 with the bacterial tetracycline repressor as a DNA binding domain. This hybrid protein binds to p53 and can interact with a synthetic promoter containing tetracycline-operator sequences. Gene expression can now be specifically achieved in tumor cells harboring an endogenous mutant p53 but not in a wild-type p53 containing tumor cell line or in a non-transformed cell line. Thus, a functional transactivator centered on single chain antibodies can be expressed intracellularly and induce gene expression in a scFv-mediated specific manner. This novel class of transcriptional transactivators could be referred as 'trabodies' for transcription-activating-antibodies. The trabodies technology could be useful to any cell type in which a disease related protein could be the target of specific antibodies.
Insights
Researchers created a novel gene therapy tool called trabodies. These synthetic transcription factors target mutant p53 in tumor cells, enabling specific gene expression for targeted therapy.
Area of Science:
- Molecular Biology
- Gene Therapy
- Immunology
Background:
- Conditional gene expression systems are crucial for targeted gene therapy.
- Developing systems that target specific pathological molecules is a key challenge.
- Existing methods lack specificity for certain cellular or tissue types.
Purpose of the Study:
- To engineer a synthetic transcription factor for conditional gene expression.
- To create a system that specifically targets tumor cells with mutant p53.
- To develop a novel class of transcription-activating antibodies ('trabodies').
Main Methods:
- Fused a single-chain variable fragment (scFv) antibody targeting p53 with a tetracycline repressor DNA-binding domain.
- Constructed a synthetic promoter with tetracycline-operator sequences.
- Tested the system's ability to induce gene expression in cell lines with mutant p53, wild-type p53, and non-transformed cells.
Main Results:
- The synthetic transcription factor specifically bound to mutant p53.
- Gene expression was successfully achieved in tumor cells harboring endogenous mutant p53.
- No significant gene expression was observed in wild-type p53 tumor cells or non-transformed cells.
- Demonstrated intracellular expression and scFv-mediated specific gene induction.
Conclusions:
- A novel class of transcriptional transactivators, termed 'trabodies', has been developed.
- Trabodies enable targeted gene expression in specific cell types based on disease-related protein expression.
- This technology holds potential for various therapeutic applications where specific antibody targeting is desired.