Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biological Engineering, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 121-132). / During the process of metastasis, tumor cells must undergo changes that enable them to detach from a tumor, exit surrounding tissue during intravasation, enter into circulation and eventually stop at a distant site for extravasation. Here, we measure the physical changes in the deformability of tumor cells, indicated by the length of time required to pass through a microfluidic constriction in a suspended microchannel resonator (SMR), as related to different stages of the metastatic process-particularly, in an epithelial-mesenchymal transition (EMT) and existence in the circulation. We find that a mesenchymal population of murine tumor cells (MMTV-PyMT) that had undergone a spontaneous EMT at the primary tumor site were more deformable than the parental population of epithelial cells. In contrast, MMTV-PyMT and Ep5 murine breast carcinoma cells that had received signaling from platelets to undergo an epithelial-mesenchymal-like transition maintained the same deformability or became less deformable, respectively. In all cases, however, epithelial and mesenchymal tumor cells both take much longer to pass through a constriction than typical blood cells, as confirmed by examining various human cancer cell lines (H1975, SKBR-3, MDA-MB231, PC3-9). Using a syngeneic mouse tumor model, we find that cells that are able to exit a tumor and enter the circulation are not required to be particularly more deformable than the cells initially injected into the mouse. However, in a limited study of prostate cancer patients, various circulating tumor cells (CTCs) can pass through a constriction quickly because some are relatively small in size, while others are more deformable than typical tumor cell lines and more mechanically similar to blood cells. Nonetheless, due to the ambiguity in cell identity when a heterogeneous sample like blood is assessed by the SMR, there was a need to correlate each cell's precision biophysical measurement to its molecular expression. I thus developed a technique whereby cells can be sorted off-chip based on their passage time and/or buoyant mass characteristics, and collected into a 96- well plate. The proof-of-principle is demonstrated by sorting and collecting cells from cell linespiked blood samples as well as a metastatic prostate cancer patient blood sample, classifying them by their surface protein expression and relating them to distinct SMR signal trajectories. Taken together, our results provide impetus for further studies on the mechanical properties of CTCs as well as the future utilization of this platform for other types of biophysical-molecular characterizations. / by Josephine W. (Shaw) Bagnall. / Ph. D.
| Identifer | oai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/99050 |
| Date | January 2015 |
| Creators | Bagnall, Josephine W. (Josephine Wen-yu Shaw) |
| Contributors | Scott R. Manalis., Massachusetts Institute of Technology. Department of Biological Engineering., Massachusetts Institute of Technology. Department of Biological Engineering. |
| Publisher | Massachusetts Institute of Technology |
| Source Sets | M.I.T. Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 132 pages, application/pdf |
| Rights | MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission., http://dspace.mit.edu/handle/1721.1/7582 |
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