Journal of Cancer Research and Clinical Oncology

, Volume 122, Issue 10, pp 603–612

Cell-cycle arrest, micronucleus formation, and cell death in growth inhibition of MCF-7 breast cancer cells by tamoxifen and cisplatin

  • Angela M. Otto
  • Renate Paddenberg
  • Sybilla Schubert
  • Hans Georg Mannherz
Original Paper Experimental Oncology

DOI: 10.1007/BF01221192

Cite this article as:
Otto, A.M., Paddenberg, R., Schubert, S. et al. J Cancer Res Clin Oncol (1996) 122: 603. doi:10.1007/BF01221192

Abstract

The induction of cell death along with cell-cycle arrest is one of the foremost mechanisms regulating cell growth. In the human breast carcinoma cell line MCF-7 we investigated two chemotherapeutic agents, the antiestrogen tamoxifen and the DNA-damaging drug cisplatin, for the relative contribution of these mechanisms to growth inhibition in culture. Growth kinetics and flow cytometry confirmed that tamoxifen at 1 μM acts mainly by arresting cells in the G0/G1 phase of the cell cycle. Compared to untreated controls, only a few more cells were detached from the monolayer and dead after a 5-day incubation. On the other hand, cisplatin at 1 μM did not induce the well-defined G2/M-arrest reported for other cell types, but resulted in a marked increase in the rate of cell death. A morphological feature observed, especially with cisplatin-treated MCF-7 cells, was the formation of numerous micronuclei (in up to 30% of the cells) and an increase in the number of binucleate cells (up to 20%). In both tamoxifen- and cisplatin-treated cultures, cell death appeared to occur by apoptosis, as indicated morphologically by cellular and nuclear shrinkage accompanied by DNA-condensation and ultimately the formation of DNA containing apoptotic bodies. However, no internucleosomal DNA degradation or endogenous endonuclease activity could be detected in the cells of the monolayer or in the mainly dead and detached cells of the culture supernatant. DNA fragmentation was only observed when isolated MCF-7 nuclei were incubated with exogenous endonucleases. However, as determined by reverse transcriptase/polymerase chain reaction amplification, MCF-7 cells do express the mRNA for DNase I, an endonuclease known to be involved in apoptosis. Thus, apoptosis is part of the growth-inhibitory process and occurs without apparent internucleosomal DNA fragmentation in MCF-7 cell cultures.

Key words

Cell-cycle arrest Cell death Micronuclei MCF-7 cells Tamoxifen Cisplatin DNA fragmentation Endonuclease 

Abbreviations

FCS

fetal calf serum

PBS

phosphate-buffered saline

Copyright information

© Springer-Verlag 1996

Authors and Affiliations

  • Angela M. Otto
    • 1
    • 2
  • Renate Paddenberg
    • 2
  • Sybilla Schubert
    • 1
  • Hans Georg Mannherz
    • 2
  1. 1.Institut für PharmazieUniversität RegensburgRegensburgGermany
  2. 2.Institut für Zytobiologie und ZytopathologiePhilipps-UniversitätMarburgGermany
  3. 3.Institute for BiochemistryUniversity of Erlangen-NürnbergErlangenGermany
  4. 4.Institut für Biologie, Abteilung BiophysikUniversität StuttgartStuttgartGermany
  5. 5.Institut für Anatomie und EmbryologieRuhr-UniversitätBochumGermany

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