Host cell cytotoxicity, cellular repopulation dynamics, and phase-specific cell survival in X-irradiated rat rhabdomyosarcoma tumors

Journal Article · Mon Jan 01 00:00:00 EST 1990 · Radiation Research; (United States)

DOI:https://doi.org/10.2307/3577654· OSTI ID:7302729

Tenforde, T S ^[1]; Kavanau, K S; Afzal, S M.J.; Curtis, S B ^[2]

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1. Pacific Northwest Lab., Richland, WA (United States)
2. Lawrence Berkeley Lab., CA (United States)

Postirradiation tumor volume response, cellular repopulation dynamics, cell-cycle perturbations, and phase-specific cell survival were characterized in rat rhabdomyosarcoma R-1 tumors (the R2C5 subline) following an in situ 10-Gy dose of 225-kVp X rays. This X-ray dose produced a 7.5-day delay in tumor growth to twice the volume measured at the time of irradiation, and reduced the initial surviving fraction of R2C5 cells to 0.17 as measured by the excision assay procedure. The surviving fraction of R2C5 cells returned to unity by the 16th day after tumor irradiation. On the basis of flow cytometry measurements of DNA content in tumor cells stained with a noncytotoxic concentration of Hoechst 33342, a transient G{sub 2} block was observed 1 day after irradiation. Flow cytometry measurements also demonstrated that the tetraploid R2C5 cells constituted only 30% of the total tumor cell population, with the remainder being diploid host cells comprised of macrophages, monocytes, lymphocytes, and granulocytes. Large numbers of host cells infiltrated the irradiated tumors, leading to an increase in the percentage of diploid cells by Day 2 and reaching a level of more than 80% of the total tumor cell population by 4 to 8 days after irradiation. The influx of host cells into irradiated tumors was correlated temporally with a significant 12-fold decrease in the surviving fraction of R2C5 cells that occurred between Days 2 and 4 postirradiation. When the diploid host cell population was removed by cell sorting procedures, the surviving fraction of R2C5 cells at Day 4 substantially greater than that in the presence of the host cells. Experiments involving the mixing of 4/1 and 12/1 ratios of diploid host cells and tetraploid tumor cells isolated from irradiated and unirradiated tumors demonstrated that the cytotoxic effect of the host cells was specific for the irradiated tumor cells.

• DOE Contract Number: AC03-76SF00098; AC06-76RL01830
• OSTI ID: 7302729
• Journal Information: Radiation Research; (United States), Vol. 123; ISSN 0033-7587
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
TUMOR CELLS
BIOLOGICAL RADIATION EFFECTS
X RADIATION
TOXICITY
CELL CULTURES
CELL CYCLE
CELL FLOW SYSTEMS
DNA
GROWTH
RATS
RHABDOMYOSARCOMAS
SURVIVAL TIME
ANIMAL CELLS
ANIMALS
BIOLOGICAL EFFECTS
DISEASES
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
MAMMALS
MYOSARCOMAS
NEOPLASMS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
RADIATION EFFECTS
RADIATIONS
RODENTS
SARCOMAS
VERTEBRATES
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture