Circulating Breast Tumor Cells Exhibit Dynamic Changes in Epithelial and Mesenchymal Composition

Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA.
Science (Impact Factor: 33.61). 02/2013; 339(6119):580-584. DOI: 10.1126/science.1228522
Source: PubMed


Epithelial-mesenchymal transition (EMT) of adherent epithelial cells to a migratory mesenchymal state has been implicated
in tumor metastasis in preclinical models. To investigate its role in human cancer, we characterized EMT in circulating tumor
cells (CTCs) from breast cancer patients. Rare primary tumor cells simultaneously expressed mesenchymal and epithelial markers,
but mesenchymal cells were highly enriched in CTCs. Serial CTC monitoring in 11 patients suggested an association of mesenchymal
CTCs with disease progression. In an index patient, reversible shifts between these cell fates accompanied each cycle of response
to therapy and disease progression. Mesenchymal CTCs occurred as both single cells and multicellular clusters, expressing
known EMT regulators, including transforming growth factor (TGF)–β pathway components and the FOXC1 transcription factor.
These data support a role for EMT in the blood-borne dissemination of human breast cancer.

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Available from: Shannon L Stott, Apr 15, 2014
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    • "It has been reported that transformation from a luminal primary to a basal-like recurrence is more likely than the opposite phenomena (Castaneda et al., 2012). Recent studies showed that FOXC1 is associated with mesenchymal circulating tumor cells from both ER + and ER – breast cancer and may induce EMT in ER + breast cancer cells (Yu et al., 2013). Thus, we explored the effect of FOXC1 on CSC properties in two ER + cell lines, MCF7 and T47D, which harbor undetectable FOXC1 levels (Figure S1A). "
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    ABSTRACT: The mesoderm- and epithelial-mesenchymal transition-associated transcription factor FOXC1 is specifically overexpressed in basal-like breast cancer (BLBC), but its biochemical function is not understood. Here we demonstrate that FOXC1 controls cancer stem cell (CSC) properties enriched in BLBC cells via activation of Smoothened (SMO)-independent Hedgehog (Hh) signaling. This non-canonical activation of Hh is specifically mediated by Gli2. We further show that the N-terminal domain of FOXC1 (aa 1-68) binds directly to an internal region (aa 898-1168) of Gli2, enhancing the DNA-binding and transcription-activating capacity of Gli2. FOXC1 expression correlates with that of Gli2 and its targets in human breast cancers. Moreover, FOXC1 overexpression reduces sensitivity to anti-Hedgehog (Hh) inhibitors in BLBC cells and xenograft tumors. Together, these findings reveal FOXC1-mediated non-canonical Hh signaling that determines the BLBC stem-like phenotype and anti-Hh sensitivity, supporting inhibition of FOXC1 pathways as potential approaches for improving BLBC treatment.
    Cell Reports 11/2015; 13(4). DOI:10.1016/j.celrep.2015.09.063 · 8.36 Impact Factor
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    • "The relevance of the CTC/EMT relationship and its role in determining metastatic outcomes in breast cancer is explored in a recent study by Yu et al., which highlights the dynamic relationship between EMT and CTC level and shows the association between cancer subtype, treatment response, and stage of disease. They reveal that EMT, and consequently mesenchymal CTCs, occur more prevalently in aggressive disease subtypes typically characterized as being highly pro-metastatic [44] [63]. The persistent increase in the total CTC numbers we observed in biopsied mice likely has a cumulative impact that favors the possibility of successful metastatic colonization (Figure 6). "
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    ABSTRACT: Introduction: Incisional biopsies, including the diagnostic core needle biopsy (CNB), routinely performed before surgical excision of breast cancer tumors are hypothesized to increase the risk of metastatic disease. In this study, we experimentally determined whether CNB of breast cancer tumors results in increased distant metastases and examine important resultant changes in the primary tumor and tumor microenvironment associated with this outcome. Method: To evaluate the effect of CNB on metastasis development, we implanted murine mammary 4T1 tumor cells in BALB/c mice and performed CNB on palpable tumors in half the mice. Subsequently, emulating the human scenario, all mice underwent complete tumor excision and were allowed to recover, with attendant metastasis development. Tumor growth, lung metastasis, circulating tumor cell (CTC) levels, variation in gene expression, composition of the tumor microenvironment, and changes in immunologic markers were compared in biopsied and non-biopsied mice. Results: Mice with biopsied tumors developed significantly more lung metastases compared to non-biopsied mice. Tumors from biopsied mice contained a higher frequency of myeloid-derived suppressor cells (MDSCs) accompanied by reduced CD4 + T cells, CD8 + T cells, and macrophages, suggesting biopsy-mediated development of an increasingly immunosuppressive tumor microenvironment. We also observed a CNB-dependent up-regulation in the expression of SOX4, Ezh2, and other key epithelial-mesenchymal transition (EMT) genes, as well as increased CTC levels among the biopsy group. Conclusion: CNB creates an immunosuppressive tumor microenvironment, increases EMT, and facilitates release of CTCs, all of which likely contribute to the observed increase in development of distant metastases.
    Neoplasia (New York, N.Y.) 11/2014; DOI:10.1016/j.neo.2014.09.004 · 4.25 Impact Factor
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    • "Consequently, mesenchymal-like CTC subpopulations are difficult to identify in the hematopoietic cell environment which is also of mesenchymal origin (Joosse & Pantel, 2013). Of note, single tumor cells found in the blood of breast cancer patients exhibit EMT-associated changes, while cell clusters appear to require a partial EMT so that these cells possess the migratory abilities of a mesenchymal cell but retain the cell–cell interaction profile of an epithelial cell (Yu et al, 2013). "
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    ABSTRACT: Cancer metastasis is the main cause of cancer-related death, and dissemination of tumor cells through the blood circulation is an important intermediate step that also exemplifies the switch from localized to systemic disease. Early detection and characterization of circulating tumor cells (CTCs) is therefore important as a general strategy to monitor and prevent the development of overt metastatic disease. Furthermore, sequential analysis of CTCs can provide clinically relevant information on the effectiveness and progression of systemic therapies (e.g., chemo-, hormonal, or targeted therapies with antibodies or small inhibitors). Although many advances have been made regarding the detection and molecular characterization of CTCs, several challenges still exist that limit the current use of this important diagnostic approach. In this review, we discuss the biology of tumor cell dissemination, technical advances, as well as the challenges and potential clinical implications of CTC detection and characterization.
    EMBO Molecular Medicine 11/2014; 7(1). DOI:10.15252/emmm.201303698 · 8.67 Impact Factor
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