Effects of azetidine-2-carboxylic acid on treatments of hepatoma cells with single or fractionated X-ray irradiations and on thermal radiosensitization in normal and thermotolerant cells
✍ Scribed by J. van Rijn; J. van den Berg; C.A. van der Mast
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 254 KB
- Volume
- 7
- Category
- Article
- ISSN
- 1065-7541
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✦ Synopsis
The amino acid analog azetidine-2-carboxylic acid (azetidine) is a potent sensitizer to both hyperthermia and ionizing radiation. Incubation of H35 hepatoma cells with 2.5 mM azetidine before or after treatments with X-rays causes a time-and sequencedependent enhancement of cell killing. Exposure of cells to 1-1.5 mM azetidine for 96 h in combination with repeated doses of 3 Gy X-rays at 24 h intervals causes an enhanced reduction of the surviving cell population due to both radiosensitization and an additional growth inhibition. Azetidine does not prevent the induction of thermotolerance after a heat shock. This thermotolerance proportionally reduces thermal radiosensitization but does not seem to affect azetidine radiosensitization. It is suggested that thermal radiosensitization and azetidine radiosensitization operate by different mechanisms.