Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
In vitro effects of 2-methoxyestradiol, an endogenous estrogen, on MCF-12A and MCF-7 cell cycle progression
Dissertation (MSc (Physiology))--University of Pretoria, 2008.
Saved in:
| Other Authors: | |
|---|---|
| Format: | Thesis |
| Published: |
University of Pretoria
2013
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613599185240064 |
|---|---|
| access_status_str | Open Access |
| author2 | Lottering, Mona-Liza |
| author_browse | Lottering, Mona-Liza |
| author_facet | Lottering, Mona-Liza |
| collection | Thesis |
| dc_rights_str_mv | © University of Pretoria 2006E367/ |
| description | Dissertation (MSc (Physiology))--University of Pretoria, 2008. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/26594 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:38:42.081Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/26594 In vitro effects of 2-methoxyestradiol, an endogenous estrogen, on MCF-12A and MCF-7 cell cycle progression Lottering, Mona-Liza catherina.vanzijl@up.ac.za Joubert, Annie M. Van Zijl, Magdalena Catherina Spindle assembly checkpoint 2-methoxyestradiol Cell cycle regulation Mitotic spindle Cdc2 kinase UCTD Dissertation (MSc (Physiology))--University of Pretoria, 2008. 2-Methoxyestradiol (2ME) is an endogenous estrogen metabolite with antiproliferative and antiangiogenic properties. 2ME also plays an active role in the induction of apoptosis, especially in cancerous cells. These properties have been confirmed by various in vitro and in vivo studies and render 2ME a potential antitumor agent. The mechanism of action of 2ME, however, is not yet fully elucidated and it is believed that multiple mechanisms are involved that may be dependent on cell type. The aim of this study was to investigate the differential effects of 2ME on cell growth, morphology and spindle formation in the non-tumorigenic MCF-12A breast cell line and the tumorigenic MCF-7 breast cell line. In dose-dependent studies, cell growth was determined spectrophotometrically. Light microscopy was used to investigate the morphological changes induced by 2ME and its effect on spindle formation was investigated by means of indirect immunofluorescence. The estrogen receptor status of the MCF-12A cells was confirmed with immunocytochemistry. In order to investigate the effect of 2ME on the length of the cell cycle, cells were blocked in early S-phase with hydroxyurea, then allowed to continue through the cell cycle and mitotic indices determined at regular time intervals. Checkpoint kinase and Cdc2 kinase assays were used to determine the effect of 2ME on relevant cell cycle kinases. Although 2ME inhibited cell growth in both cell lines, the MCF-7 cells were inhibited from much lower concentrations and growth inhibition was more pronounced than in the MCF-12A cells. Treated MCF-7 cells showed abnormal metaphase cells, membrane blebbing, apoptotic cells and disrupted spindle formation. These observations were either absent, or not as prominent in the MCF-12A cells. Therefore, differential mechanism(s) of growth inhibition are evident between the normal and tumorigenic cells. Although the two cell lines differ in their estrogen receptor status, this could not explain the differential effects, for 2ME has a very low affinity for the estrogen receptor. 2ME had no effect on the length of the cell cycle, but blocked MCF-7 cells in mitosis. There were no significant alterations in the phosphorylation status of Cdc25C after 2ME treatment. However, Cdc2 activity was increased to a greater extend in the MCF-7 cells than in the MCF-12A cells. Therefore, it is suggested that exposure to 2ME disrupts mitotic spindle formation and enhances Cdc2 kinase activity, leading to persistence of the spindle checkpoint and thus prolonged metaphase arrest, which may result in the induction of apoptosis. The tumorigenic MCF-7 cells are especially sensitive to 2ME treatment compared to the normal MCF-12A cells. 2ME shows potential for the treatment of breast cancer. Selecting the concentration of 2ME that has maximum inhibitory effect on tumorigenic, but minimal effect on normal cells is crucial in its possible application as antitumor agent. Furthermore, research concerning the differential action mechanisms of 2ME is essential to create a better understanding regarding the treatment of cancer and may possibly contribute to the development and/or improvement of novel chemotherapeutic agents. Physiology unrestricted 2013-09-07T06:44:35Z 2007-08-20 2013-09-07T06:44:35Z 2006-01-21 2008-08-20 2007-07-24 Dissertation a 2006E367/ag http://hdl.handle.net/2263/26594 http://upetd.up.ac.za/thesis/available/etd-07242007-094315/ © University of Pretoria 2006E367/ application/pdf University of Pretoria |
| spellingShingle | Spindle assembly checkpoint 2-methoxyestradiol Cell cycle regulation Mitotic spindle Cdc2 kinase UCTD In vitro effects of 2-methoxyestradiol, an endogenous estrogen, on MCF-12A and MCF-7 cell cycle progression |
| title | In vitro effects of 2-methoxyestradiol, an endogenous estrogen, on MCF-12A and MCF-7 cell cycle progression |
| title_full | In vitro effects of 2-methoxyestradiol, an endogenous estrogen, on MCF-12A and MCF-7 cell cycle progression |
| title_fullStr | In vitro effects of 2-methoxyestradiol, an endogenous estrogen, on MCF-12A and MCF-7 cell cycle progression |
| title_full_unstemmed | In vitro effects of 2-methoxyestradiol, an endogenous estrogen, on MCF-12A and MCF-7 cell cycle progression |
| title_short | In vitro effects of 2-methoxyestradiol, an endogenous estrogen, on MCF-12A and MCF-7 cell cycle progression |
| title_sort | in vitro effects of 2 methoxyestradiol an endogenous estrogen on mcf 12a and mcf 7 cell cycle progression |
| topic | Spindle assembly checkpoint 2-methoxyestradiol Cell cycle regulation Mitotic spindle Cdc2 kinase UCTD |
| url | http://hdl.handle.net/2263/26594 http://upetd.up.ac.za/thesis/available/etd-07242007-094315/ |