Open AccessCELL KINETICS OF IRRADIATED EXPERIMENTAL TUMORS: CELL TRANSITION FROM THE NON‐PROLIFERATING TO THE PROLIFERATING POOL
Author(s) -
Potmesil M.,
Goldfeder A.
Publication year - 1980
Publication title -
cell proliferation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.647
H-Index - 74
eISSN - 1365-2184
pISSN - 0960-7722
DOI - 10.1111/j.1365-2184.1980.tb00495.x
Subject(s) - mitosis , nucleolus , biology , cell cycle , metaphase , thymidine , cell , pathology , microbiology and biotechnology , cytoplasm , in vitro , biochemistry , chromosome , medicine , gene
Parenchymal tumor cells of murine mammary carcinomas can be divided into two pools, using nucleoli as morphological ‘markers’. Cells with dense nucleoli traverse the cell cycle and divide, thus constituting the proliferating pool. Cells with trabeculate or ring‐shaped nucleoli either proceed slowly through G 1 phase or are arrested in it. The role of these non‐proliferating, G 1 phase‐confined cells in tumor regeneration was studied in vivo after a subcurative dose of X‐irradiation in two transplantable tumor lines. Tumor‐bearing mice were continuously injected with methyl[ 3 H]thymidine before and after irradiation. Finally, the labeling was discontinued, mice injected with vincristine sulfate and cells arrested in metaphase were accumulated over a 10‐hr period. Two clearly delineated groups of vincristinearrested mitoses emerged in autoradiograms prepared from tumor tissue at the time of starting tumor regrowth: one group with the silver‐grain counts corresponding to the background level, the other with heavily labeled mitoses. As the only source of unlabeled mitoses was unlabeled G 1 phase‐confined cells persisting in the tumor, this observation indicated cell transition from the non‐proliferating to the proliferating pool, which took place in the initial phase of the tumor regrowth. Unlabeled progenitors have apparently remained in G 1 phase for at least 5–12 days after irradiation.