Related Experiment Video
Updated: Jan 22, 2026
06:53
Quantification of γH2AX Foci in Response to Ionising Radiation
Published on: April 6, 2010
21.0K
Reduced exosomal L-Plastin is responsible for radiation-induced bystander effect
Lena Katharina Freudenmann1, Claus Mayer1, H Peter Rodemann1
1Division of Radiobiology and Molecular Environmental Research, Department of Radiation Oncology, University of Tübingen, Germany; DKFZ Partner Site Tübingen, German Cancer Consortium (DKTK), Germany.
Experimental Cell Research
|July 15, 2019
Summary
Radiation-induced bystander effects involve factors transmitted between cells. Researchers identified L-Plastin, secreted by cancer cells via exosomes, as responsible for these effects, and radiotherapy inhibits its production.
Area of Science:
- Oncology
- Cell Biology
- Radiotherapy Research
Background:
- Radiation-induced bystander effects (RIBE) are critical in radiotherapy, but the molecular mediators remain unclear.
- Previous hypotheses suggested DNA-damaging factors, but this study explores alternative mechanisms.
- Understanding these intercellular signaling pathways is crucial for optimizing cancer treatment.
Purpose of the Study:
- To identify the specific molecular factor(s) responsible for transmitting growth-inhibitory and DNA-damaging signals in radiation-induced bystander effects.
- To elucidate the role of L-Plastin in mediating these effects and its regulation by irradiation.
Main Methods:
- PC3 cells were irradiated to produce conditioned medium (CM).
- A549 indicator cells were incubated with CM to assess clonogenic survival and proliferation.
- L-Plastin was identified using immunoprecipitation and siRNA-mediated knockdown; exosome transport was analyzed.
Main Results:
- A radiation-triggered reduction in mitogenic/clonogenic activity, not DNA damage, mediated the bystander effect.
- Tumor cells, but not normal fibroblasts, secrete this factor, with irradiation reducing its release.
- L-Plastin, secreted via exosomes and phosphorylated, was identified as the key mediator of this activity.
Conclusions:
- Cancer cells secrete L-Plastin via exosomes, influencing the tumor microenvironment's clonogenic and mitogenic activity.
- Radiotherapy inhibits L-Plastin production, potentially explaining its efficacy in tumor control.
- This finding offers new insights into intercellular communication in cancer and response to radiation therapy.
More Related Videos
Related Concept Videos
02:09Bystander Effect
10.2K
The discussion of bullying highlights the problem of witnesses not intervening to help a victim. This is a common occurrence, as the following well-publicized event demonstrates. In 1964, in Queens, New York, a 19-year-old woman named Kitty Genovese was attacked by a person with a knife near the back entrance to her apartment building and again in the hallway inside her apartment building. When the attack occurred, she screamed for help numerous times and eventually died from her stab wounds.
10.2K
02:59Biological Effects of Radiation
17.7K
All radioactive nuclides emit high-energy particles or electromagnetic waves. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. For example, α and β particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. When these particles strike and penetrate matter, they...
17.7K
01:17Radiation: Applications
1.7K
The average temperature of Earth is the subject of much current discussion. Earth is in radiative contact with both the Sun and dark space; it receives almost all its energy from the radiation of the Sun and reflects some of it into outer space. Dark space is very cold, about 3 K, so Earth radiates energy into it. For instance, heat transfer occurs from soil and grasses, the rate of which can be so rapid that frost can occur on clear summer evenings, even in warm latitudes.
The average...
The average...
1.7K
01:36Overview of Exosomes
3.6K
Exosomes are stable, lipid bilayer-enclosed vesicles capable of crossing biological barriers. They can carry a wide range of molecules required for intercellular communication. Once exosomes are released from the cell where they originated, they enter a recipient cell through various pathways such as fusion, receptor-mediated endocytosis, macropinocytosis, and phagocytosis.
Stahl et al. discovered exosomes in 1983, but the exosomes were initially considered waste products released from the...
Stahl et al. discovered exosomes in 1983, but the exosomes were initially considered waste products released from the...
3.6K
01:05Absorption of Radiation
1.2K
The rate of heat transfer by emitted radiation is described by the Stefan-Boltzmann law of radiation:
1.2K
01:18Reducing Line Loss
370
In a three-phase circuit, line loss is an indicator of energy dissipated as heat due to the resistance of transmission lines. To address this, incorporating transformers into the system—a step-up transformer at the source and a step-down transformer at the load—is a strategic solution. Two three-phase transformers are introduced to improve this.
With a step-up transformer at the source, the voltage is increased, thereby reducing the current in the transmission lines since power loss in...
With a step-up transformer at the source, the voltage is increased, thereby reducing the current in the transmission lines since power loss in...
370