Biomaterial Database

Correlation of tumor sensitivity to low-dose-rate irradiation with G2/M-phase block and other radiobiological parameters. 1993

S J Knox, and W Sutherland, and M L Goris

Department of Radiation Oncology, Stanford University Medical Center, California 94305.

The efficacy of exponentially decreasing low-dose-rate irradiation was compared with that of equivalent doses of multiply fractionated high-dose-rate external-beam irradiation in mice with three different kinds of tumors that varied in terms of alpha/beta ratio, tumor volume doubling times, and cell cycle times. Cell cycle distribution was measured after low-dose-rate and high-dose-rate irradiation. The relative efficacy of low-dose-rate irradiation versus equivalent doses of high-dose-rate irradiation was correlated with the extent of arrest of cells in G2 phase of the cell cycle. Unlike 38C13 murine B-cell lymphoma, neither the HT29 human colorectal xenograft or the SNB75 human glioblastoma xenograft was significantly more sensitive to low-dose-rate than fractionated high-dose-rate irradiation. The 38C13 B-cell lymphoma also had the shortest tumor volume doubling and cell cycle times, the most G2 arrest after low-dose-rate irradiation, more G2 arrest with low-dose-rate than high-dose-rate irradiation, and the highest alpha/beta ratio. The data presented here support the hypothesis that dose-rate effects may be minimal for tumors with small shoulders and large alpha/beta ratios and that arrest of cells in G2 phase plays an important role in cell death mediated by low-dose-rate irradiation. The proliferative rates of tumor cells may modify dose-rate effects further, and the interaction of all of these factors may explain in part the increased efficacy of low-dose-rate irradiation and radioimmunotherapy compared with high-dose-rate irradiation that has been reported in some animal models.

UI	MeSH Term	Description	Entries
D008809	Mice, Inbred C3H	An inbred strain of mouse that is used as a general purpose strain in a wide variety of RESEARCH areas including CANCER; INFECTIOUS DISEASES; sensorineural, and cardiovascular biology research.	Mice, C3H,Mouse, C3H,Mouse, Inbred C3H,C3H Mice,C3H Mice, Inbred,C3H Mouse,C3H Mouse, Inbred,Inbred C3H Mice,Inbred C3H Mouse
D008938	Mitosis	A type of CELL NUCLEUS division by means of which the two daughter nuclei normally receive identical complements of the number of CHROMOSOMES of the somatic cells of the species.	M Phase, Mitotic,Mitotic M Phase,M Phases, Mitotic,Mitoses,Mitotic M Phases,Phase, Mitotic M,Phases, Mitotic M
D011879	Radiotherapy Dosage	The total amount of radiation absorbed by tissues as a result of radiotherapy.	Dosage, Radiotherapy,Dosages, Radiotherapy,Radiotherapy Dosages
D001932	Brain Neoplasms	Neoplasms of the intracranial components of the central nervous system, including the cerebral hemispheres, basal ganglia, hypothalamus, thalamus, brain stem, and cerebellum. Brain neoplasms are subdivided into primary (originating from brain tissue) and secondary (i.e., metastatic) forms. Primary neoplasms are subdivided into benign and malignant forms. In general, brain tumors may also be classified by age of onset, histologic type, or presenting location in the brain.	Brain Cancer,Brain Metastases,Brain Tumors,Cancer of Brain,Malignant Primary Brain Tumors,Neoplasms, Intracranial,Benign Neoplasms, Brain,Brain Neoplasm, Primary,Brain Neoplasms, Benign,Brain Neoplasms, Malignant,Brain Neoplasms, Malignant, Primary,Brain Neoplasms, Primary Malignant,Brain Tumor, Primary,Brain Tumor, Recurrent,Cancer of the Brain,Intracranial Neoplasms,Malignant Neoplasms, Brain,Malignant Primary Brain Neoplasms,Neoplasms, Brain,Neoplasms, Brain, Benign,Neoplasms, Brain, Malignant,Neoplasms, Brain, Primary,Primary Brain Neoplasms,Primary Malignant Brain Neoplasms,Primary Malignant Brain Tumors,Benign Brain Neoplasm,Benign Brain Neoplasms,Benign Neoplasm, Brain,Brain Benign Neoplasm,Brain Benign Neoplasms,Brain Cancers,Brain Malignant Neoplasm,Brain Malignant Neoplasms,Brain Metastase,Brain Neoplasm,Brain Neoplasm, Benign,Brain Neoplasm, Malignant,Brain Neoplasms, Primary,Brain Tumor,Brain Tumors, Recurrent,Cancer, Brain,Intracranial Neoplasm,Malignant Brain Neoplasm,Malignant Brain Neoplasms,Malignant Neoplasm, Brain,Neoplasm, Brain,Neoplasm, Intracranial,Primary Brain Neoplasm,Primary Brain Tumor,Primary Brain Tumors,Recurrent Brain Tumor,Recurrent Brain Tumors,Tumor, Brain
D005260	Female		Females
D005910	Glioma	Benign and malignant central nervous system neoplasms derived from glial cells (i.e., astrocytes, oligodendrocytes, and ependymocytes). Astrocytes may give rise to astrocytomas (ASTROCYTOMA) or glioblastoma multiforme (see GLIOBLASTOMA). Oligodendrocytes give rise to oligodendrogliomas (OLIGODENDROGLIOMA) and ependymocytes may undergo transformation to become EPENDYMOMA; CHOROID PLEXUS NEOPLASMS; or colloid cysts of the third ventricle. (From Escourolle et al., Manual of Basic Neuropathology, 2nd ed, p21)	Glial Cell Tumors,Malignant Glioma,Mixed Glioma,Glial Cell Tumor,Glioma, Malignant,Glioma, Mixed,Gliomas,Gliomas, Malignant,Gliomas, Mixed,Malignant Gliomas,Mixed Gliomas,Tumor, Glial Cell,Tumors, Glial Cell
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
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
D015179	Colorectal Neoplasms	Tumors or cancer of the COLON or the RECTUM or both. Risk factors for colorectal cancer include chronic ULCERATIVE COLITIS; FAMILIAL POLYPOSIS COLI; exposure to ASBESTOS; and irradiation of the CERVIX UTERI.	Colorectal Cancer,Colorectal Carcinoma,Colorectal Tumors,Neoplasms, Colorectal,Cancer, Colorectal,Cancers, Colorectal,Carcinoma, Colorectal,Carcinomas, Colorectal,Colorectal Cancers,Colorectal Carcinomas,Colorectal Neoplasm,Colorectal Tumor,Neoplasm, Colorectal,Tumor, Colorectal,Tumors, Colorectal