Open AccessMeasurement of c‐myc protein content and cell cycle kinetics of normal and spontaneously transformed murine mastocytes by bivariate flow cytometry
Author(s) -
Giaretti W.,
Vinci A. Di,
Geido E.,
Marsano B.,
Minks M.,
Bruno S.
Publication year - 1990
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.1365-2184.1990.tb01139.x
Subject(s) - flow cytometry , bivariate analysis , kinetics , chemistry , cell , cell cycle , microbiology and biotechnology , biology , biochemistry , mathematics , physics , statistics , quantum mechanics
. Progressive in vitro culturing of interleukin‐3 (IL‐3) dependent normal murine mastocytes (PB‐3) resulted in a variant cell line (PB‐1) able to grow without exogenous IL‐3 and which was tumorogenic in syngenic mice. Bivariate flow cytometry was used to evaluate the c‐myc protein and DNA content of PB‐3 and PB‐1 cells. The c‐myc protein was detected by specific monoclonal antibodies. Kinetic characteristics of PB‐3 and PB‐1 cell lines, namely, the duration of the G 1 , S and G 2 + M cell cycle phases were also evaluated using the bromodeoxyuridine (BrdU) pulse‐chase method and BrdU/DNA flow cytometry. Levels of c‐myc protein in PB‐1 cells were about twofold higher than those of PB‐3 cells in all cell cycle phases. Mean duration of the cell cycle ( T c ) was 15‐3 h for PB‐3 cells and 12‐4 h for PB‐1 cells. Shortening in T c for the transformed cells was due to a decrease of nearly 30% in mean duration of the G 1 phase (from 8 h to 5.7 h). No significant differences were found in the duration of the S and G 2 + M phases. These results indicate that acquired IL‐3 independency in vitro and tumorogenicity of PB‐1 cells were accompanied by a doubling of c‐myc protein level and by a parallel shortening, or bypass, of the regulatory events within the G 1 phase of the cell cycle.