Biomaterial Database

Therapeutic effect of m-[131I]- and m-[125I]iodobenzylguanidine on neuroblastoma multicellular tumor spheroids of different sizes. 1996

W Weber, and J Weber, and R Senekowitsch-Schmidtke

Department of Nuclear Medicine, Technische Universität München, Munich, Germany.

m-[l25I]iodobenzylguanidine (m-[125I]MIBG) has been suggested as an alternative to m-[131I]MIBG for the treatment of metastatic neuroblastoma to achieve a higher radiation dose in micrometastases. To compare these two radiopharmaceuticals, a mathematical model was developed in the present study that allows for the calculation of radiation dose rates within small spherical tumors for different distributions of 131I and 125I. Furthermore, the relationship between tumor size and the therapeutic effects of m-[131I]- and m-[125I]MIBG was studied in vitro using multicellular tumor spheroids of the neuroblastoma cell line SK-N-SH. According to the calculations, higher mean dose rates can be achieved by m-[125I]MIBG than by m-[131I]MIBG up to a tumor diameter of 100 microm when both substances are homogeneously distributed within the tumor. In larger tumors, however, mean dose rates achieved by 131I are up to 8-fold higher. Evaluation of various activity distributions demonstrated that even in tumors of less than 100 microm in diameter, marked heterogeneities of the dose rate can occur when m-[125I]MIBG is not distributed homogeneously. By treatment with m-[131I]MIBG, the growth of tumor spheroids ranging from 100 to 250 microm in diameter was inhibited more effectively in the larger than in the smaller spheroids. The growth inhibition of spheroids treated with m-[125I]MIBG was independent of the spheroid size. In consistency with the calculations, the therapeutic effect of m-[125I]- and m-[131I]MIBG was equal in spheroids with diameters of about 100 microm. In larger spheroids, m-[131I]MIBG induced a more pronounced delay in spheroid growth than m-[125I]MIBG. According to these calculations and in vitro data, m-[125I]MIBG as a single agent does not seem to be a promising alternative to m-[131I]MIBG for treatment of metastatic neuroblastoma. However, the combined use of m-[131I]- and m-[125I]MIBG may be more effective than treatment with m-[131I]MIBG alone.

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
D007462	Iodobenzenes	Any derivative of BENZENE that contains IODINE.
D009447	Neuroblastoma	A common neoplasm of early childhood arising from neural crest cells in the sympathetic nervous system, and characterized by diverse clinical behavior, ranging from spontaneous remission to rapid metastatic progression and death. This tumor is the most common intraabdominal malignancy of childhood, but it may also arise from thorax, neck, or rarely occur in the central nervous system. Histologic features include uniform round cells with hyperchromatic nuclei arranged in nests and separated by fibrovascular septa. Neuroblastomas may be associated with the opsoclonus-myoclonus syndrome. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2099-2101; Curr Opin Oncol 1998 Jan;10(1):43-51)	Neuroblastomas
D004307	Dose-Response Relationship, Radiation	The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.	Dose Response Relationship, Radiation,Dose-Response Relationships, Radiation,Radiation Dose-Response Relationship,Radiation Dose-Response Relationships,Relationship, Radiation Dose-Response,Relationships, Radiation Dose-Response
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D014407	Tumor Cells, Cultured	Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.	Cultured Tumor Cells,Neoplastic Cells, Cultured,Cultured Neoplastic Cells,Cell, Cultured Neoplastic,Cell, Cultured Tumor,Cells, Cultured Neoplastic,Cells, Cultured Tumor,Cultured Neoplastic Cell,Cultured Tumor Cell,Neoplastic Cell, Cultured,Tumor Cell, Cultured
D018874	Spheroids, Cellular	Spherical, heterogeneous aggregates of proliferating, quiescent, and necrotic cells in culture that retain three-dimensional architecture and tissue-specific functions. The ability to form spheroids is a characteristic trait of CULTURED TUMOR CELLS derived from solid TUMORS. Cells from normal tissues can also form spheroids. They represent an in-vitro model for studies of the biology of both normal and malignant cells. (From Bjerkvig, Spheroid Culture in Cancer Research, 1992, p4)	Multicellular Spheroids,Cellular Spheroid,Cellular Spheroids,Multicellular Spheroid,Spheroid, Cellular,Spheroid, Multicellular,Spheroids, Multicellular
D019797	3-Iodobenzylguanidine	A guanidine analog with specific affinity for tissues of the sympathetic nervous system and related tumors. The radiolabeled forms are used as antineoplastic agents and radioactive imaging agents. (Merck Index, 12th ed) MIBG serves as a neuron-blocking agent which has a strong affinity for, and retention in, the adrenal medulla and also inhibits ADP-ribosyltransferase.	(3-Iodo-(131I)benzyl)guanidine,Iobenguane,MIBG,3-Iodobenzylguanidine, 123I Labeled,3-Iodobenzylguanidine, 125I Labeled,Iobenguane (131I),m-Iodobenzylguanidine,meta-Iodobenzylguanidine,123I Labeled 3-Iodobenzylguanidine,125I Labeled 3-Iodobenzylguanidine,3 Iodobenzylguanidine,3 Iodobenzylguanidine, 123I Labeled,3 Iodobenzylguanidine, 125I Labeled,m Iodobenzylguanidine,meta Iodobenzylguanidine