Open AccessA TECHNIQUE FOR DETERMINING THE PROPORTION OF THE CLONOGENIC CELLS IN S PHASE IN EMT6 CELL CULTURES AND TUMORS
Author(s) -
Rockwell Sara,
Frindel Emilia,
Tubiana Maurice
Publication year - 1976
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.1365-2184.1976.tb01279.x
Subject(s) - clonogenic assay , incubation , in vivo , in vitro , thymidine , cell , biology , cell culture , microbiology and biotechnology , tissue culture , andrology , immunology , biochemistry , medicine , genetics
The survival of cultured EMT6 cells was examined after treatment with hydroxyurea (HU) or high specific activity tritiated thymidine ( 3 H‐TdR). The concentrations of the agents, duration of exposure to the agents, and post‐exposure treatment of the cultures were found to influence the cell survival; the effects of these factors are reported. Conditions were defined under which the proportions of cells killed by HU and by 3 H‐TdR were the same and were also the same as the proportion of labeled cells seen on autoradiographs of cultures labeled with small doses of 3 H‐TdR. Under these conditions, either 3 H‐TdR or HU could be used to determine the proportion of the clonogenic cells in S phase. Single cell suspensions prepared from solid EMT6 tumors were treated in vitro with HU or 3 H‐TdR, using the conditions found optimal for each agent with cultured cells. The proportion of the tumor cells killed by treatment with HU in vitro was the same as the proportion killed by HU in vivo and as the proportion labeled by 3 H‐TdR in vivo, and incubation of tumor cell suspensions with HU in vitro appeared to provide a valid measurement of the proportion of clonogenic tumor cells in S phase. Incubation of tumor cell suspensions with 3 H‐TdR in vitro proved difficult to perform and the results were relatively unreliable because of severe problems with reutilization of 3 H‐TdR during the incubation for colony formation.