Open AccessActivated cell cycle checkpoints in epirubicin‐treated breast cancer cells studied by BrdUrd‐flow cytometry
Author(s) -
Hedenfalk Ingrid A.,
Baldetorp Bo,
Borg Åke,
Oredsson Stina M.
Publication year - 1997
Publication title -
cytometry
Language(s) - English
Resource type - Journals
eISSN - 1097-0320
pISSN - 0196-4763
DOI - 10.1002/(sici)1097-0320(19971201)29:4<321::aid-cyto9>3.0.co;2-c
Subject(s) - epirubicin , flow cytometry , cell cycle , biology , cancer research , bromodeoxyuridine , cell , microbiology and biotechnology , cancer , breast cancer , cell growth , genetics
Genetic alterations, such as p53 mutations, may affect a tumour's response to chemotherapy. We have treated two human breast cancer cell lines that differ in p53 status with epirubicin in order to study if there are differences in cell cycle kinetic response. MCF‐7 cells express wild‐type p53 , while SK‐BR‐3 cells express only a mutated form of p53 . The transition of cells from one cell cycle stage to another was studied by a bromodeoxyuridine (BrdUrd)‐flow cytometry (FCM) method. MCF‐7 cells showed a block in the G 1 phase after treatment with 50 nM epirubicin for 24 hours, in agreement with the actions of p53 at the G 1 checkpoint. SK‐BR‐3 cells, on the other hand, progressed through the G 1 checkpoint and were blocked in late S and G 2 phases, presumably due to the activation of a later checkpoint. In addition, studies of the mRNA levels of p53 and its effector gene p21 revealed that although both cell lines expressed p53 mRNA, a marked difference in the mRNA levels of p21 was seen. A dramatic increase in the level of p21 mRNA was seen in epirubicin‐treated MCF‐7 cells, while no such increase was seen in SK‐BR‐3 cells. Cytometry 29:321–327, 1997. © 1997 Wiley‐Liss, Inc.