Image cytometry of progesterone receptor expression during the cell cycle in the MCF-7 cell line

• Published in: The journal of histochemistry and cytochemistry 1991-12, Vol.39 (12), p.1713-1718
• Main Authors: Cassanelli, S, Guillaud, P, Louis, J, Seigneurin, D
• Format: Article
• Language: English
• Subjects: Breast Neoplasms - metabolism; Breast Neoplasms - pathology; Bromodeoxyuridine; Cell Cycle; DNA, Neoplasm - metabolism; Flow Cytometry; Fluorescent Antibody Technique; Humans; Image Processing, Computer-Assisted; Microscopy, Fluorescence; Receptors, Progesterone - metabolism; Tumor Cells, Cultured
• ISSN: 0022-1554; 1551-5044
• DOI: 10.1177/39.12.1940323

Progesterone receptors (PR) appear to be distributed in a heterogeneous way in mammary tumor cells. The study presented here was designed to examine if heterogeneity of PR expression is cell-cycle dependent. Immunofluorescence techniques were used to label PR on the MCF-7 human breast cancer cell line and image cytometry was used to analyze the PR expression during G0 (Ki-67 antigen-negative cells), G1, S, and G2/M cell-cycle phases. A second PR, BrdU, and DNA analysis was performed to study PR expression in the S-phase (BrdU-positive cells). Our results show that PR synthesis occurs preferentially during the G0-G1 transition and that PR levels are constant during the G1-G2 transition. The PR expression appears to be cell-cycle related and may therefore explain the heterogeneity of PR expression. However, the possibility that PR heterogeneity may be linked to the existence of PR-negative subclones cannot be ruled out.