抄録
Multicellular spheroids of rat glioma clone-6 cells were developed in a spinner flask. The histological appearance of these mature spheroids was similar to that of tumor cord structure of solid tumors in vivo. Namely, spheroids showed a central necrosis surrounded by a viable rim. The viable rim was composed of actively proliferating cells (P cells) in the outer cell-layers and of non-proliferating cells (Q cells) in the inner layers.
The X-ray dose-survival curve of cells in the mature spheroids was biphasic, indicating the presence of hypoxic cells, whereas the dose-survival curve of single cells from the same batch of the spheroids was monophasic.
Mature spheroids were killed more effectively with 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) treatment than cells grown as a monolayer. Response of small spheroids without necrosis to ACNU was intermediate. Comparison of ACNU treatment under various conditions indicated that single cells from mature spheroids were most sensitive to ACNU. These results suggest that cells highly sensitive to ACNU may be located close to the central necrosis.
