Metastasis is a major contributor to breast cancer mortality, as currently available therapies are unable to ensure progression or disease-free survival. Little is known about the molecular pathogenesis of metastasis, and the role of the surrounding microenvironment is only beginning to be understood. In vitro studies have repeatedly shown that epithelial to mesenchymal transition (EMT) and loss of E-cadherin expression are critical events in the initiation of metastasis and can be induced by the microenvironment. However, metastases are often well-differentiated and epithelial in phenotype, suggesting that EMT is reversible. The role of E-cadherin expression and mesenchymal to epithelial reverting transition (MErT) in metastatic colonization of the secondary site remains ill-defined. Evidence for E-cadherin re-expression and partial MErT was observed in metastases of breast and prostate cancer patients, and suggests that MErT is unstable and reversible. MDA-MB-231 breast cancer cells cultured with hepatocytes also resulted in E-cadherin re-expression and partial MErT, suggesting that such phenotypic plasticity can be induced by the microenvironment of the liver, a key site of breast cancer metastases. Re-expression of E-cadherin following hepatocyte coculture not only results in heterotypic ligation between cancer and liver parenchymal cells, but also activates Erk survival signaling and increases resistance to nutrient-deprivation and chemotherapy. Taken together, our results indicate that the distant organ microenvironment may induce E-cadherin re-expression and partial MErT to enhance the survival of metastatic cancer cells at the secondary organ.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-02282011-124755 |
| Date | 09 March 2011 |
| Creators | Chao, Yvonne Lai |
| Contributors | Alan Wells, Marie DeFrances, Reza Zarnegar, Stephen Strom, Jorg Gerlach |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-02282011-124755/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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