Comparative Analysis of Transcriptional Gene Regulation Indicates Similar Physiologic Response in Mouse Tissues at Low Absorbed Doses from Intravenously Administered 211At

Journal of Nuclear Medicine

Britta Langen¹  Khalil Helou¹  Emil Schüler¹  Eva Forssell-Aronsson¹  Toshima Z. Parris¹  Nils Rudqvist¹ 

关键词: ²¹¹At;    normal tissue response;    transcriptional gene regulation;    biological processes;    radionuclide therapy;   

DOI  :  10.2967/jnumed.112.114462

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

211At is a promising therapeutic radionuclide because of the nearly optimal biological effectiveness of emitted α-particles. Unbound 211At accumulates in the thyroid gland and in other vital normal tissues. However, few studies have been performed that assess the 211At-induced normal-tissue damage in vivo. Knowledge about the extent and quality of resulting responses in various organs offers a new venue for reducing risks and side effects and increasing the overall well-being of the patient during and after therapy. Methods: Female BALB/c nude mice were injected intravenously with 0.064–42 kBq of 211At or mock-treated, and the kidneys, liver, lungs, and spleen were excised 24 h after injection. A transcriptional gene expression analysis was performed in triplicate using RNA microarray technology. Biological processes associated with regulated transcripts were grouped into 8 main categories with 31 subcategories according to gene ontology terms for comparison of regulatory profiles. Results: A substantial decrease in the total number of regulated transcripts was observed between 0.64 and 1.8 kBq of 211At for all investigated tissues. Few genes were differentially regulated in each tissue at all absorbed doses. In all tissues, most of these genes showed a nonmonotonous dependence on absorbed dose. However, the direction of regulation generally remained uniform for a given gene. Few known radiation-associated genes were regulated on the transcriptional level, and their expression profile generally appeared to be dose-independent and tissue-specific. The regulatory profiles of categorized biological processes were tissue-specific and reflected the shift in regulatory intensity between 0.64 and 1.8 kBq of 211At. The profiles revealed strongly regulated and nonregulated subcategories. Conclusion: The strong regulatory change observed between 0.64 and 1.8 kBq is hypothesized to result not only from low-dose effects in each tissue but also from physiologic responses to ionizing radiation-induced damage to, for example, the 211At-accumulating thyroid gland. The presented results demonstrate the complexity of responses to radionuclides in vivo and highlight the need for further research to also consider physiology in ionizing radiation-induced responses.

【 授权许可】

Unknown