Image cytometry of progesterone receptor expression during the cell cycle in the MCF-7 cell line.
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.
Cassanelli
S
S
Equipe de Cytologie Quantitative, Laboratoire d'Histologie, Génétique et Biologie de la Reproduction, Faculté de Médecine de Grenoble, La Tronche, France.
Guillaud
P
P
Louis
J
J
Seigneurin
D
D
D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D001973:Bromodeoxyuridine; D002453:Cell Cycle; D004273:DNA, Neoplasm / Q000378:metabolism; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008856:Microscopy, Fluorescence; D011980:Receptors, Progesterone / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D004273:DNA, Neoplasm; D011980:Receptors, Progesterone; D001973:Bromodeoxyuridine