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Biochemical modulation of radiation-induced apoptosis in murine lymphoma cells
R E Meyn1, L C Stephens, D W Voehringer
1Department of Experimental Radiotherapy, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Abstract:
Considerable effort in our laboratory has been directed toward characterizing the role of apoptosis as a mode of cell death in model tumors irradiated in vivo. These studies have shown that apoptosis is an important response in some tumors, correlating with tumor growth delay and tumor cure. However, the response is heterogeneous among both the various tumors examined and the cells in a given tumor, suggesting that the propensity for cells to undergo apoptosis upon irradiation is regulated by unknown factors in tumors. To develop a model system for investigating these regulatory pathways in vitro at the molecular and biochemical levels, we have established cells from a tumor that displays a dramatic apoptotic response in vivo, the TH lymphoma, in cell culture. In this article, we review some of the results of our studies using this model system. To date, we have shown that the dose-response relationship and kinetics of the development of apoptosis for these cells in culture are similar to what we observed for the tumor response in vivo. Moreover, the roles of calcium and signal transduction pathways as important regulatory factors in radiation-induced apoptosis have been defined in this system. Ultimately such investigations may yield the insight necessary for designing protocols to modulate apoptosis biochemically in irradiated normal and tumor tissues to therapeutic advantage.
Insights
Radiation-induced apoptosis, programmed cell death, is a key factor in tumor response. This study established a cell culture model to investigate the molecular regulation of apoptosis in irradiated TH lymphoma cells.
Area of Science:
- Oncology
- Cell Biology
- Radiation Biology
Background:
- Apoptosis (programmed cell death) is a critical determinant of tumor response to radiation therapy.
- The propensity of tumor cells to undergo apoptosis varies significantly, indicating the presence of unknown regulatory factors within tumors.
Purpose of the Study:
- To establish an in vitro model system for investigating the molecular and biochemical regulation of radiation-induced apoptosis.
- To utilize the TH lymphoma, a tumor with a known high apoptotic response in vivo, for detailed cellular studies.
Main Methods:
- Establishing TH lymphoma cells in cell culture to mimic in vivo radiation response.
- Analyzing dose-response relationships and kinetics of apoptosis development in vitro.
- Investigating the roles of calcium and signal transduction pathways in regulating apoptosis.
Main Results:
- The in vitro model system demonstrated dose-response and kinetic profiles for apoptosis similar to in vivo observations.
- Calcium and signal transduction pathways were identified as significant regulatory factors in radiation-induced apoptosis.
- The heterogeneity of apoptotic response in tumors suggests complex regulatory mechanisms.
Conclusions:
- The established cell culture model provides a valuable platform for dissecting molecular pathways of radiation-induced apoptosis.
- Understanding these pathways, including calcium and signal transduction, is crucial for developing strategies to enhance therapeutic outcomes.
- Future research aims to leverage these findings for biochemical modulation of apoptosis in irradiated tissues.