A microfluidic device for label-free, physical capture of circulating tumor cell clusters

Abstract

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. 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 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.

Circulating tumor cell technologies

“…Constructed from parylene-C, can process WB, captures viable cells, clusters observed Kaifi et al, 2015) 3D FaCTChecker Constructed from parylene-C, captures viable cells between membrane layers Parsortix Viable cells released by reversing flow Resettable Cell Trap Pneumatically-controlled microvalves (Qin et al, 2015) Cluster Chip Triangular pillars designed for CTC clusters (Sarioglu et al, 2015) Biophysical e Inertial Focusing Cells are passively separated by size through the application of inertial forces in microfluidic devices that affect positioning within the flow channel.…”

“…Sarioglu et al recently reported the development of a novel three-dimensional microfiltration system specifically designed to capture CTC clusters called the Cluster-Chip (Sarioglu et al, 2015). Multiple studies using microfiltration for CTC isolation have reported capturing CTC clusters (aka microemboli) (Desitter et al, 2011;Harouaka et al, 2014;Ilie et al, 2014;Vona et al, 2000).…”

Circulating Tumor Cells and Circulating Tumor DNA: Challenges and Opportunities on the Path to Clinical Utility

“…Also known as circulating tumor microemboli, clusters immunomagnetically captured usng the CELLSEARCH platform have been identified in more than 30% of patients with small cell lung cancer and appear to lack apoptotic or proliferating cells, perhaps offering a survival advantage (84). The use of a new device, the Cluster-Chip, offers label-free isolation of CTC clusters with the use of triangular pillars acting as microfluidic "cluster traps" (85). This method showed that clusters were identified in 30% to 40% of patients with metastatic melanoma, breast cancer, and prostate cancer, with the majority of clusters containing 2 to 10 cells, although sometimes up to 19 cells.…”

“…Similarly, circulating cancer-associated macrophage-like cells from patients with metastatic breast, prostate, and pancreatic cancers can disseminate into the circulation and interact with CTCs (90), with some observed to migrate bound to CTCs, potentially facilitating distant colonization and neovascularization. CTC clusters may express markers associated with platelet transcripts and/or tissue-derived macrophages, but not T/B/natural killer (NK) cells (85). Refinements in our ability to interrogate CTCs and associated cells may enable more rapid clinical development of targeted agents that can affect the metastatic cascade.…”

Linear-array-based photoacoustic tomography for label-free high-throughput detection and quantification of circulating melanoma tumor cell clusters

“…Taking advantage of tumor-specific physical and biological properties, such as sizes and surface biomarkers, multiple technologies have been developed to capture and isolate single CTCs and CTC clusters [5][6][7] . However, most of these existing technologies require blood to be drawn to isolate and capture CTCs ex vivo, reducing the effective CTC detection sensitivity.…”