Related Experiment Video
Updated: Jun 1, 2026
08:35
Inducible and Reversible Dominant-negative (DN) Protein Inhibition
Published on: January 7, 2019
Summary
Empty plasmid DNA, when transferred directly in vivo, inhibited tumor growth and prolonged survival in mice. This highlights the critical need for proper controls in cancer gene therapy research.
Area of Science:
- Oncology
- Molecular Biology
- Gene Therapy
Background:
- Gene therapy aims to treat diseases by transferring therapeutic genes.
- The use of 'empty' plasmid DNA as a control in cancer gene therapy studies is crucial.
- Understanding the effects of non-therapeutic DNA transfer is essential for accurate experimental design.
Purpose of the Study:
- To investigate the impact of direct in vivo transfer of 'empty' plasmid DNA on tumor growth.
- To evaluate the efficacy of naked and liposome-encapsulated plasmid DNA in a murine sarcoma model.
- To underscore the importance of appropriate controls in cancer gene therapy research.
Main Methods:
- Murine MC-induced sarcoma Mc12 was transplanted into syngeneic mice.
- Tumor-bearing mice received peritumoral injections of naked or liposome-incorporated 'empty' plasmid DNA (BCMGNeo and pON1).
- Tumor growth and mouse survival were monitored.
Main Results:
- Both 'empty' plasmid DNA preparations significantly inhibited tumor growth.
- Direct in vivo transfer of 'empty' plasmid DNA significantly prolonged the survival of tumor-bearing mice.
- Liposomal incorporation enhanced plasmid DNA delivery for tumor inhibition.
Conclusions:
- 'Empty' plasmid DNA can exert a direct biological effect on tumor growth.
- The findings emphasize the necessity of rigorous controls in gene therapy studies.
- Proper controls are vital for the accurate evaluation of therapeutic gene efficacy in cancer treatment.
Related Concept Videos
02:23Abnormal Proliferation
Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
02:15Experimental RNAi
RNA interference (RNAi) is a cellular mechanism that inhibits gene expression by suppressing its transcription or activating the RNA degradation process. The mechanism was discovered by Andrew Fire and Craig Mello in 1998 in plants. Today, it is observed in almost all eukaryotes, including protozoa, flies, nematodes, insects, parasites, and mammals. This precise cellular mechanism of gene silencing has been developed into a technique that provides an efficient way to identify and determine the...
01:12Loss of Tumor Suppressor Gene Functions
Tumor suppressor genes are normal genes that can slow down cell division, repair DNA mistakes, or program the cells for apoptosis in case of irreparable damage. Hence, they play an essential role in preventing the proliferation of damaged cells.
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
01:52Eukaryotic Transcription Inhibitors
Certain biochemical processes, such as embryonic development and cell growth regulation, depend on the repression of specific genes. DNA binding proteins known as eukaryotic transcription inhibitors regulate the repression of gene expression in eukaryotes. The presence of these inhibitors at the required location and time in the cell is triggered by the presence of hormones and additional signals from other cells.
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
01:28Inhibitors of Bacterial DNA Synthesis
Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These antibiotics are selectively...
01:28Plasmids
Plasmids are extrachromosomal DNA molecules found in bacteria, archaea, and some eukaryotic microbes like yeast. These small, circular DNA structures typically contain fewer than 30 genes, although some may exist linearly. Plasmids vary in their number within a cell, known as copy number. Single-copy plasmids are present in one copy per cell and multi-copy plasmids are present in multiple copies, reaching over 100 copies per cell.Plasmids usually replicate independently of the chromosomal DNA...