Project description:Clusters of circulating tumor cells (CTC-clusters) are present in the blood of patients with cancer but their contribution to metastasis is not well defined. Here, we first use mouse models to demonstrate that breast cancer cells injected intravascularly as clusters are more prone to survive and colonize the lungs than single cells. Primary mammary tumors comprised of tagged cells give rise to oligoclonal CTC-clusters, with 50-fold increased metastatic potential, compared with single CTCs. Using intravital imaging and in vivo flow cytometry, CTC-clusters are visualized in the tumor circulation, and they demonstrate rapid clearance in peripheral vessels. In patients with breast cancer, presence of CTC-clusters is correlated with decreased progression-free survival. RNA sequencing identifies the cell junction protein plakoglobin as most differentially expressed between clusters and single human breast CTCs. Expression of plakoglobin is required for efficient CTC-cluster formation and breast cancer metastasis in mice, while its expression is associated with diminished metastasis-free survival in breast cancer patients. Together, these observations suggest that plakoglobin-enriched primary tumor cells break off into the vasculature as CTC-clusters, with greatly enhanced metastasis propensity. RNA-seq from 29 samples (15 pools of single CTCs and 14 CTC-clusters) isolated from 10 breast cancer patients
Project description:Clusters of circulating tumor cells (CTC-clusters) are present in the blood of patients with cancer but their contribution to metastasis is not well defined. Here, we first use mouse models to demonstrate that breast cancer cells injected intravascularly as clusters are more prone to survive and colonize the lungs than single cells. Primary mammary tumors comprised of tagged cells give rise to oligoclonal CTC-clusters, with 50-fold increased metastatic potential, compared with single CTCs. Using intravital imaging and in vivo flow cytometry, CTC-clusters are visualized in the tumor circulation, and they demonstrate rapid clearance in peripheral vessels. In patients with breast cancer, presence of CTC-clusters is correlated with decreased progression-free survival. RNA sequencing identifies the cell junction protein plakoglobin as most differentially expressed between clusters and single human breast CTCs. Expression of plakoglobin is required for efficient CTC-cluster formation and breast cancer metastasis in mice, while its expression is associated with diminished metastasis-free survival in breast cancer patients. Together, these observations suggest that plakoglobin-enriched primary tumor cells break off into the vasculature as CTC-clusters, with greatly enhanced metastasis propensity.
Project description:The presence of circulating tumor cell (CTC) clusters is associated with disease progression, new metastasis formation and reduced survival in a variety of cancer types. In breast cancer, pre-clinical studies showed that inhibitors of the Na+/K+-ATPase can suppress CTC clusters shedding and block metastasis. Here, we conducted a prospective, open-label, phase I study in patients with metastatic breast cancer, where the primary endpoint was to determine whether a short (one week) treatment with the Na+/K+-ATPase inhibitor digoxin could reduce mean CTC cluster size. Mechanistically, transcriptome profiling of CTCs highlighted downregulation of cell-cell adhesion and cell cycle-related genes upon treatment with digoxin, in line with its cluster-dissolution activity. ClinicalTrials.gov identifier: NCT03928210.
Project description:Recent technological advances have made it possible to detect circulating breast cancer cells as precursors of distant metastasis and as prognosis marker in nonmetastatic breast cancer patients. Association of circulating tumor cells (CTCs) with molecular alteration in the primary tumor is not widely explored. We reported differential profile of altered genome, copy number alteration and copy-neutral loss of heterogeneity in 14 primary tumors when comparing patients with CTCs+ versus CTCs- using single-nucleotide polymorphism array. The most prevalent copy number alteration in CTCs+ patients was at 8q and particularly at the cytoband 8q24 (MYC loci). As the role of MYC in the process of tumor cell invasion and migration is controversial, we further validated in a larger series of patients whether altered MYC (amplification or gained) in primary tumors was correlated with the presence of CTCs in peripheral blood (as a surrogate of micrometastais). No correlation between MYC alteration and presence of CTCs was observed, providing clinical support to the recent data that MYC suppresses cancer metastasis or at least suggesting that MYC alteration could be contributory but insufficient for the generation of CTCs. This molecular association needs to be further characterized in preclinical model and especially clinically. We analyzed CN and LOH of CTC+ and CTC-
Project description:E-cadherin (E-cad) mediates cell-cell adhesion and has been proposed to suppress both invasion and metastasis. However, invasive ductal cancers retain E-cad expression in the primary tumor, circulating tumor cells, and distant metastases. We recently demonstrated that cancer cell clusters are efficient metastatic seeds. Since clusters organize through cell-cell adhesion, we tested the requirement for E-cad in genetically engineered mouse models of luminal and basal breast cancer. Loss of E-cad increased invasion and dissemination in 3D culture and in the mammary gland. However, E-cad loss also reduced cancer cell proliferation, survival, tumor cell seeding, and metastatic outgrowth in the lungs. At the transcript level, loss of E-cad was associated with increased apoptosis. Consistent with these results, inhibition of apoptosis partially rescued the metastatic phenotype of E-cad null cancer cells. We therefore propose that E-cad is an invasion suppressor, survival factor, and metastasis promoter in invasive ductal cancers.
Project description:Cancer cells metastasize through the bloodstream either as single migratory circulating tumor cells (CTCs) or as multicellular groupings (CTC-clusters). Existing technologies for CTC enrichment are designed primarily to isolate single CTCs, and while CTC-clusters are detectable in some cases, their true prevalence and significance remain to be determined. Here, we developed a microchip technology (Cluster-Chip) specifically designed to capture CTC-clusters independent of tumor-specific markers from unprocessed blood. CTC-clusters are isolated through specialized bifurcating traps under low shear-stress conditions that preserve their integrity and even two-cell clusters are captured efficiently. Highly parallel architecture of the chip allows deterministic screening of clinically relevant volumes of blood samples at slow, and hence, non-damaging flow rates. Using the Cluster-Chip, we identify CTC-clusters in 30-40% of patients with metastatic cancers of the breast, prostate and melanoma. RNA sequencing of CTC-clusters confirms their tumor origin and identifies leukocytes within the clusters as being tissue-derived macrophages. Together, the development of a device for efficient capture of CTC-clusters will enable detailed characterization of their biological properties and role in cancer metastasis. We used the Cluster-Chip to capture CTC-clusters from the blood of a breast cancer patient with high CTC counts, released CTC-clusters in solution, stained them with TexasRed-conjugated antibodies against the leukocyte cell surface markers CD45, CD14 and CD16, and then isolated intact CTC-clusters individually using a micromanipulator. From a single time point, we retrieved 15 CTC-clusters, and each of those clusters was individually subjected to RNA-sequencing analysis using a next generation platform (SOLiD 5500). In addition, two leukocytes were isolated from the blood of a healthy donor were individually subjected to RNA-sequencing analysis using the same platform.
Project description:Gene expressional analysis with single cell scale by next generation sequencer revealed clonal dissemination in cancer metastasis. To reveal expressional heterogeneity and cell-cell interaction in the primary tumor and the metastasis, we performed transcriptome analysis of micro-tissues dissected from triple negative breast cancer (TNBC) cell line MDA-MB-231 xenograft model by our automated tissue micro-dissection punching technology. This “multiple micro-tissue transcriptome analysis” revealed that there existed three clusters in primary tumor and axillary lymph-node metastasis, two of which were cancer stem cell-like clusters (CD44/MYC-high, HMGA1-high).
Project description:We demonstrated that natural killer (NK) cells selectively suppress single circulating tumor cells (CTCs) and monoclonal metastasis compared to multicellular CTC clusters and polyclonal metastasis. To better understand how NK cells influence overall metastatic evolution, we generated spontaneous AT3 breast cancer lung metastasis in immunodeficient Rag2-/-IL2rg-/- mice, and treated mice with or without adoptive transfer of NK cells. RNA-seq on individual laser-capture microdissected lesions confirmed the infiltration of NK cells. The expression of epithelial-to-mesenchymal transition (EMT) genes strongly correlated with expression of genes indicating NK cell activation, consistent with experimental data from our lab and others.