The effects of BCL-2 over-expression on apoptosis in MCF-10A breast epithelial cells / by Matthew M. Smith.
| Author/creator | Smith, Matthew M. author. |
| Other author | Farwell, Mary A., degree supervisor. |
| Other author | East Carolina University. Department of Biology. |
| Format | Theses and dissertations |
| Production | 2006. |
| Description | vi, 84 leaves : illustrations (some color) ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | Bcl-2, an anti-apoptotic mitochondrial protein, is the prototypical member of a family of proteins that are key regulators of apoptosis. Many cancers, including breast, express Bcl-2 at high levels. This over-expression could indicate that the mitochondrial apoptotic pathway is important to cancer development in these cells. Our laboratory is interested in the link between apoptosis and mitochondrial activity in non-cancerous breast epithelial cells. We hypothesize that breast epithelial cells undergo growth factor withdrawal-induced apoptosis in a mitochondria-dependent fashion. We used MCF-lOA immortalized breast epithelial cells that over-expressed Bcl-2 to test the response to apoptotic inducers. The presence of Bcl-2 over-expression was confirmed by Western blot. Interestingly, Bax expression increased in response to the Bcl-2 over-expression. Analysis of these cells revealed a significantly lower growth rate, and inhibition of staurosporine-induced apoptosis. However, experiments with growth factor withdrawal have indicated that Bcl-2 over-expression does not block apoptosis from occurring. These results differ from what has been found for other cell types in which Bcl-2 over expression inhibits apoptosis following growth factor withdrawal. Western blots found cleaved caspase 9 in both staurosporine- and growth factor withdrawal-induced apoptosis. This indicates that both trigger the mitochondria-dependent pathway of apoptosis. Results from treatment with the microtubule inhibitor colchicine indicate that while Bcl-2 over-expression may delay the onset of colchicine-induced apoptosis, it ultimately makes the cells more susceptible to death. We hypothesize that changes in the amount of Bcl-2, phosphorylation of Bcl-2, and increased Bax expression in our cells may be the reason for the unexpected results. Taken together, these results indicate that although affecting staurosporine sensitivity, Bcl-2 over-expression does not block growth factor withdrawal or colchicine-induced apoptosis in these cells. |
| General note | Presented to the faculty of the Department of Biology. |
| General note | Advisor: Mary A. Farwell |
| Dissertation note | M.S. East Carolina University 2006 |
| Bibliography note | Includes bibliographical references (leaves 59-68). |
| Genre/form | dissertations. |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
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