Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2018 Oct 2;115(40):9986-9991. doi: 10.1073/pnas.1803884115. Epub 2018 Sep 17.

Functional profiling of circulating tumor cells with an integrated vortex capture and single-cell protease activity assay.

Author information

1
Department of Bioengineering, Samueli School of Engineering, University of California, Los Angeles, CA 90095.
2
Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095.
3
VA Greater Los Angeles Healthcare System, Los Angeles, CA 90073.
4
UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095.
5
Department of Urology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095.
6
Department of Bioengineering, Samueli School of Engineering, University of California, Los Angeles, CA 90095; dicarlo@ucla.edu.
7
Department of Mechanical and Aerospace Engineering, Samueli School of Engineering, University of California, Los Angeles, CA 90095.

Abstract

Tumor cells are hypothesized to use proteolytic enzymes to facilitate invasion. Whether circulating tumor cells (CTCs) secrete these enzymes to aid metastasis is unknown. A quantitative and high-throughput approach to assay CTC secretion is needed to address this question. We developed an integrated microfluidic system that concentrates rare cancer cells >100,000-fold from 1 mL of whole blood into ∼50,000 2-nL drops composed of assay reagents within 15 min. The system isolates CTCs by size, exchanges fluid around CTCs to remove contaminants, introduces a matrix metalloprotease (MMP) substrate, and encapsulates CTCs into microdroplets. We found CTCs from prostate cancer patients possessed above baseline levels of MMP activity (1.7- to 200-fold). Activity of CTCs was generally higher than leukocytes from the same patient (average CTC/leukocyte MMP activity ratio, 2.6 ± 1.5). Higher MMP activity of CTCs suggests active proteolytic processes that may facilitate invasion or immune evasion and be relevant phenotypic biomarkers enabling companion diagnostics for anti-MMP therapies.

KEYWORDS:

cell secretion; circulating tumor cells; liquid biopsy; microfluidics; protease

PMID:
30224472
PMCID:
PMC6176626
[Available on 2019-04-02]
DOI:
10.1073/pnas.1803884115
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center