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Updated: Aug 23, 2025
DNA Vector-based RNA Interference to Study Gene Function in Cancer
Published on: June 4, 2012
G-Quadruplex Linked DNA Guides Selective Transfection into Nucleolin-Overexpressing Cancer Cells
Mengxi Xiang1, Yongkui Li1, Jia Liu1
1Research Center for Tissue Engineering and Regenerative Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Abstract:
Gene therapy is a promising approach for treating tumors. Conventional approaches of DNA delivery depending on non-viral or viral vectors are unsatisfactory due to the concerns of biosafety and cell-targeting efficiency. The question how to deliver DNA into tumor cells efficiently and selectively is a major technological problem in tumor gene therapy. Here, we develop a vector-free gene transfer strategy to deliver genes effectively and selectively by taking advantage of targeting nucleolin. Nucleolin, a shuttle protein moving between cell membrane, cytoplasm and nuclei, is overexpressed in tumor cells. It has a natural ligand G-quadruplex (Gq). Gq-linked DNA (Gq-DNA) is likely to be internalized by ligand dependent uptake mechanisms independently of vectors after neutralizing negative charges of cell membrane by targeting nucleolin. This strategy is referred to as Gq-DNA transfection. Benefiting from its high affinity to nucleolin, Gq-DNA can be effectively delivered into nucleolin-positive tumor cells even nuclei. Gq-DNA transfection is characterized by low cytotoxicity, high efficiency, ease of synthesis, high stability in serum, direct access into nuclei, and specific nucleolin-positive tumor cell targeting.
Insights
This study introduces Gq-DNA transfection, a novel vector-free gene therapy method. It efficiently and selectively delivers genes into tumor cells by targeting the nucleolin protein, overcoming limitations of traditional vectors.
Area of Science:
- Biotechnology
- Molecular Biology
- Oncology
Background:
- Gene therapy offers promise for cancer treatment but faces challenges with current DNA delivery vectors.
- Non-viral and viral vectors have limitations regarding biosafety and targeting efficiency in tumor gene therapy.
- Efficient and selective DNA delivery to tumor cells remains a critical hurdle.
Purpose of the Study:
- To develop a vector-free gene transfer strategy for efficient and selective tumor cell gene delivery.
- To utilize the nucleolin protein's overexpression in tumor cells for targeted gene delivery.
- To establish a novel gene transfer method called Gq-DNA transfection.
Main Methods:
- Developed Gq-DNA (G-quadruplex linked DNA) for vector-free gene transfer.
- Leveraged nucleolin, a protein overexpressed in tumor cells, as a targeting mechanism.
- Utilized nucleolin's natural ligand, G-quadruplex, for DNA internalization via ligand-dependent uptake.
Main Results:
- Gq-DNA transfection demonstrated effective and selective delivery of genes into nucleolin-positive tumor cells.
- The strategy showed high efficiency and direct access to cell nuclei.
- The method exhibited low cytotoxicity and high stability in serum.
Conclusions:
- Gq-DNA transfection is a promising vector-free strategy for tumor gene therapy.
- Targeting nucleolin offers a selective and efficient approach for DNA delivery to tumor cells.
- This method overcomes key limitations of conventional gene delivery vectors.
