Deadly metastases occur when tumor cells are shed from a primary tumor into lymph and blood that disseminate circulating tumor cells (CTCs) throughout the body. Therefore, early detection of CTCs at potentially treatable disease stage may improve patient survival rate. While CTCs in blood have been subjected of many studies, a little progress has been made in research of lymphatic CTCs (L-CTCs). The goal of this dissertation project is to introduce a new test to identify CTCs in lymph fluid and establish the significance of L-CTCs for metastasis development using preclinical models of metastatic tumors, flow cytometry in vivo and lymph liquid biopsy in vitro.
In Specific Aim 1, an innovative strategy was developed for diagnosis of L-CTCs at single cell level in peripheral and central lymph. First, in vivo flow cytometry using photoacoustic and fluorescence detection schematics was optimized to provide highly sensitive counting of L-CTCs. Next, lymph liquid biopsy was introduced to achieve molecular and genetic analysis of L-CTCs in vitro. Finally, lymph and blood tests were integrated to beneficiary increase their diagnostic values.
Studies in Specific Aim 2 established the in vivo significance of L-CTC counts and developed integrative assessment of L-CTC and blood CTCs (B-CTCs). Using metastatic melanoma and breast cancer mice models, we demonstrated the presence of detectable L-CTCs at pre-metastatic disease, estimated the correlation between CTCs, primary tumor, and metastasis, and observed parallel L-CTCs and B-CTCs dissemination.
Specific Aim 3 was designed to determine whether L-CTCs are heterogeneous cell populations containing cells responsible for metastasis initiation. Using lymph liquid biopsy, stem L-CTCs were defined in afferent lymph which underlines the significance of the lymphatic pathway in development of sentinel lymph node (SLN) metastasis. Furthermore, stem L-CTCs and L-CTCs with high expression of genes driving metastasis were discovered in thoracic duct (TD) lymph, suggesting that L-CTCs participate in the initiation of distant metastasis.
The results obtained in this work lay the scientific foundation to consider L-CTCs as a prognostic marker of metastasis and to emphasize integrative assessment of lymph and blood.
|Advisor:||Galanzha, Ekaterina I.|
|Commitee:||Zharov, Vladimir P., Griffin, Robert J., Kelly, Thomas J., Tackett, Alan J.|
|School:||University of Arkansas for Medical Sciences|
|Department:||Interdisciplinary Biomedical Sciences|
|School Location:||United States -- Arkansas|
|Source:||DAI-B 82/6(E), Dissertation Abstracts International|
|Subjects:||Cellular biology, Oncology, Molecular biology, Public health, Pathology|
|Keywords:||Lymphatic circulation, Tumor cells, Tumor metastasis, Liquid biopsy , In vivo, In vitro, Blood testing, Breast cancer, Prognosis marker|
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