High throughput, label-free isolation of circulating tumor cell clusters in meshed microwells
Ontology highlight
ABSTRACT: Extremely rare circulating tumor cell (CTC) clusters are both increasingly appreciated as highly metastatic precursors and virtually unexplored. Technologies are primarily designed to detect single CTCs and often fail to account for the fragility of clusters or to leverage cluster-specific markers for higher sensitivity. Meanwhile, the few technologies targeting CTC clusters lack scalability. Here, we introduce the Cluster-Wells, which combines the speed and practicality of membrane filtration with the sensitive and deterministic screening afforded by microfluidic chips. The >100,000 microwells in the Cluster-Wells physically arrest CTC clusters in unprocessed whole blood, gently isolating virtually all clusters at a throughput of >25 mL/h, and allow viable clusters to be retrieved from the device. Using the Cluster-Wells, we isolated CTC clusters ranging from 2–100+ cells from prostate and ovarian cancer patients and analyzed a subset using RNA sequencing. Routine isolation of CTC clusters will democratize research on their utility in managing cancer.
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: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.
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:Circulating tumor cell clusters/micro-emboli (CTM) possess greater metastatic capacity and survival advantage compared to individual circulating tumor cell (CTCs). However, the formation of CTM subtypes and their role in tumor metastasis remain unclear. In this study, we used a microfluidic Cluster-chip with easy operation and high efficiency to isolate CTM from peripheral blood, which confirmed their correlation with clinicopathological features and identified the critical role of CTC-platelet clusters in BC metastasis. The correlation between platelets and CTM function was further confirmed in a mouse model and RNA-seq of CTM identified high-expressed genes related to hypoxia stimulation and platelet activation which possibly suggested the correlation of hypoxia and CTC-platelet cluster formation. In conclusion, we successfully developed the Cluster-chip platform to realize the clinical capture of CTMs and analyze the biological properties of CTC-platelet clusters, which could benefit the design of potential treatment regimens to prevent CTM-mediated metastasis and tumor malignant progression.
Project description:The immune ecosystem, particularly T cells, is central to maintaining effective anti-tumor responses. However, how immune cells in the periphery blood interact with circulating tumor cells (CTCs) - critical mediators of metastatic spread 1-8 – remains largely unexplored. Here, our analysis of the blood specimens from patients with advanced breast cancer (N=1,529) revealed that over 75% of the CTC-positive blood specimens contained heterotypic CTC clusters with CD45+ white blood cells (WBCs). These CTC-WBC clusters correlate with breast cancer subtypes (triple negative and luminal B), racial groups (Black), and unfavorable clinical outcomes. Using flow cytometry and ImageStream, we characterized the diverse WBC composition in these heterotypic clusters, such as overrepresented T cells and underrepresented neutrophils. Most strikingly, a rare subset of CD4 and CD8 double positive T (DPT) cells showed an up to 140-fold enrichment in the CTC clusters (~14.2%) versus its frequency in WBCs (0.1%). DPT cells shared part of profiles with CD4+ T cells and others with CD8+ T cells but exhibited unique features of T cell exhaustion and immune suppression (TIM-3 and PD-1). Single-cell RNA sequencing further identified distinct cell adhesion profiles of DPT cells and CTCs. CRISPR/Cas9-mediated gene depletion pinpointed the integrin VLA4 (β1/α4) in DPT and its ligand VCAM1 in tumor cells as essential mediators of heterotypic CTC clusters. Anti-α4 (VLA4) neutralizing antibodies markedly reduced CTC–DPT cell clustering and blocked metastatic lesion formation in murine models in vivo. These findings uncover a pivotal role for a rare T cell subset in fostering cancer dissemination through heterotypic CTC cluster interactions. It lays a foundation for innovative therapeutic strategies aimed at preventing and targeting metastasis of breast cancer, thus benefiting Black and non-Black patients.
Project description:The ability of circulating tumor cells (CTCs) to form clusters has been linked to increased metastatic potential. Yet biological features and vulnerabilities of CTC clusters remain largely unknown. Our DNA methylation analysis led us to hypothesize that CTC clusters are characterized by active TF networks that support both stemness and proliferation. To identify whether the stemness- and proliferation-related TF networks are also transcriptionally active in CTC clusters compared to single CTCs, we performed single-cell resolution RNA sequencing analysis of single CTCs and CTC clusters, matched within individual liquid biopsies and isolated from six breast cancer patients with progressive metastatic disease, and of single CTCs and CTC clusters isolated from three xenograft models. In addition, among 2,486 FDA-approved compounds, we identify Na+/K+ ATPase inhibitors that enable the dissociation of CTC clusters into single cells, leading to DNA methylation remodeling at critical sites and metastasis suppression. We performed RNA sequencing analysis of BR16 and Brx50 cells upon treatment to assess the molecular consequences of clusters dissociation.