Abstract
Background: Antioxidants have the potential to protect normal tissues against radiation-induced damage, but must not protect tumor cells during radiotherapy. The major objectives were to determine whether a metalloporphyrin antioxidant affects prostate tumor response to radiation and identify possible mechanisms of interaction.
Materials and Methods: C57BL/6 mice with RM-9 tumor were treated with manganese (III) meso-tetrakis(1,3-diethylimidazolium-2- yl)porphyrin (MnTDE-2-ImP) and 10 gray (Gy) radiation. Tumor volume was quantified and a subset/group was evaluated for hypoxia-inducible factor-1· (HIF-1·), bone marrow-derived cell populations and cytokines.
Results: The addition of MnTDE-2-ImP transiently increased tumor response compared to radiation alone. The group receiving drug plus radiation had reduced intratumoral HIF-1· and decreased capacity to secrete TNF-·, whereas production of IL-4 was increased. There were no toxicities associated with combination treatment.
Conclusion: The results demonstrate that MnTDE-2-ImP did not protect the RM-9 prostate tumor against radiation; instead, radiation effectiveness was modestly increased. Possible mechanisms include reduction of radiationinduced HIF-1· and an altered cytokine profile.
| Original language | American English |
|---|---|
| Journal | Anticancer Research |
| Volume | 27 |
| State | Published - Jan 1 2007 |
Keywords
- Ionizing radiation
- antioxidant
- RM-9 prostate cancer
- HIF-1·
- cytokines
- immune system
- angiogenesis.
Disciplines
- Biology
- Oncology