J Korean Soc Ther Radiol Oncol.  2009 Dec;27(4):218-227. 10.3857/jkstro.2009.27.4.218.

Different Expressions of HIF-1alpha, Bcl-2 and Baxin DU145 Prostate Cancer Cells Transplanted in Nude Mouse between X-Ray and Neutron Irradiation

• Kong M
• Kang JO
• Kim SK
• Shin DO
• Park SH
• Kim CJ
• Chang HK

• KMID: 2003435
• DOI: http://doi.org/10.3857/jkstro.2009.27.4.218

Abstract

PURPOSE
To investigate the radiobiologic effects of neutron and X-ray irradiation on DU-145 prostate carcinoma cells by identifying the differences of HIF-1alpha expression and apoptosis. MATERIALS AND METHODS: Nude mice were injected with the human prostate cancer cell line, DU-145, and then irradiated with 2 Gy and 10 Gy X-rays, or 0.6 Gy and 3.3 Gy neutrons, respectively. The mice were sacrificed at 24 hours and 120 hours after irradiation. The expression levels of HIF-1alpha, Bcl-2 and Bax were compared with immunohistochemical staining and western blotting. The apoptotic indexes were compared with the Terminal deoxynucleotidyl biotin-dUTP nick and labeling (TUNEL) assay. RESULTS: At day 1, HIF-1alpha and Bcl-2 expression decreased, while Bax expression and the number of TUNEL positive cells increased in neutron irradiated groups for the control and X-ray irradiated groups. The Bcl-2/Bax ratio was significantly lower in the neutron irradiated groups regardless of dose (p=0.001). The same pattern of the differences in the expressions of the HIF-1alpha, Bcl-2, Bax, Bcl-2/Bax ratio, and apoptotic indexes were indentified at day 5. HIF-1alpha expression was related with Bcl-2 (p=0.031), Bax (p=0.037) expressions and the apoptotic indexes (p=0.016) at day 5. CONCLUSION: Neutron irradiation showed a decrease in HIF-1alpha, Bcl-2 expression, and Bcl-2/Bax ratio, but increased Bax expression regardless of dose. This study suggests that the differences radiobiological responses between photon and neutron irradiation may be related to different HIF-1alpha expression and subsequent apoptotic protein expressions.

Keyword

HIF-1alpha; Bcl-2; Bax; Neutron; Prostate cancer

MeSH Terms

Animals
Apoptosis
Blotting, Western
Cell Line
Humans
In Situ Nick-End Labeling
Mice
Mice, Nude
Neutrons
Prostate
Prostatic Neoplasms
Transplants