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High dose fractionated ionizing radiation inhibits prostate cancer cell adhesion and beta(1) integrin expression
Edmund L Simon1, Hira L Goel, Natalia Teider
1Department of Radiation Oncology, University of Massachusetts Memorial Health Care Hospitals, Worcester, Massachusetts 01605, USA.
Background:
The effect of ionizing radiation on extracellular matrix (ECM)-mediated cellular functions is an important area of research for translational science. Mechanisms of tumor cell ability to proliferate, migrate, and survive appear dependent on integrin-mediated adhesion to the ECM; however, the exact role therapeutic radiation plays in altering signaling pathways and promoting cell death within remains less well established.
Methods:
To examine these effects on prostate carcinoma cell lines, cells were irradiated at sub-lethal doses. We have studied two human prostate cancer cell lines (PC3 and DU-145) irradiated with different fractionated radiation schedules. Three groups were compared to non-irradiated controls. Group A was given a single dose of 5 Gy. Group B was given 5 Gy the first week and then 10 Gy the second week for a total of 15 Gy. Group C was given 5 Gy the first week, and then 10 Gy the second and third week for a total of 25 Gy. Cells were analyzed at their prescribed total dose. At 48 hr post irradiation, cells were detached from culture dishes and were subsequently used for adhesion assays and immunoblotting analysis.
Results:
Our findings revealed that two prostate carcinoma cell lines, PC3 and DU-145, had a reduced cellular adhesion to fibronectin (FN) compared to the non-irradiated control groups. Both prostate cancer cell lines showed decreased adhesion to FN and reduced beta(1) integrin protein levels at a total dose of 25 Gy, but not at the doses of 15 and 5 Gy. In a parallel analysis, at the maximum total dose of 25 Gy, both PC3 and DU-145 demonstrated a significant decrease in cell proliferation.
Conclusions:
High dose radiation treatment of prostate cancer cell lines inhibits integrin expression. Our study suggests that promoting a synergistic decrease in adhesion could bring additional therapeutic benefit to patients treated with radiation therapy.
Insights
High-dose radiation therapy for prostate cancer can reduce cancer cell adhesion and proliferation by inhibiting integrin expression. This suggests combining radiation with adhesion-blocking strategies may enhance treatment efficacy.
Area of Science:
- Oncology
- Radiation Biology
- Cellular Biology
Background:
- Extracellular matrix (ECM)-mediated cellular functions are crucial for tumor progression.
- Integrin-mediated adhesion to the ECM influences cancer cell proliferation, migration, and survival.
- The impact of therapeutic radiation on these signaling pathways is not fully understood.
Purpose of the Study:
- To investigate the effects of ionizing radiation on prostate carcinoma cell lines.
- To examine how radiation alters integrin expression and cellular adhesion.
- To determine the role of radiation dose in these cellular changes.
Main Methods:
- Two human prostate cancer cell lines (PC3 and DU-145) were irradiated with fractionated doses (5 Gy, 15 Gy, 25 Gy).
- Cells were analyzed for adhesion to fibronectin (FN) and beta(1) integrin protein levels.
- Cell proliferation was assessed at 48 hours post-irradiation.
Main Results:
- Irradiation with a total dose of 25 Gy significantly reduced cellular adhesion to fibronectin in both cell lines.
- Decreased beta(1) integrin protein levels were observed at 25 Gy, correlating with reduced adhesion.
- Cell proliferation was significantly inhibited at the highest radiation dose (25 Gy).
Conclusions:
- High-dose radiation therapy inhibits integrin expression in prostate cancer cells.
- Reduced cell adhesion due to radiation may offer a synergistic therapeutic benefit.
- Targeting integrin-mediated adhesion could enhance radiation therapy outcomes for prostate cancer patients.
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