Single-cell RNA sequencing identifies extracellular matrix gene expression by pancreatic circulating tumor cells.
Bottom Line: To define their composition, we compared genome-wide expression profiles of CTCs with matched primary tumors in a mouse model of pancreatic cancer, isolating individual CTCs using epitope-independent microfluidic capture, followed by single-cell RNA sequencing.Mouse as well as human pancreatic CTCs exhibit a very high expression of stromal-derived extracellular matrix (ECM) proteins, including SPARC, whose knockdown in cancer cells suppresses cell migration and invasiveness.The aberrant expression by CTCs of stromal ECM genes points to their contribution of microenvironmental signals for the spread of cancer to distant organs.
Affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA; Department of Medicine, Harvard Medical School, Boston, MA 02114, USA.Show MeSH
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Mentions: The CTC-iChip combines initial hydrodynamic size-based separation of all nucleated cells (leukocytes [WBCs] and CTCs) away from red blood cells, platelets, and plasma, with subsequent inertial focusing of the nucleated cells into a single streamline to achieve high-efficiency in-line magnetic sorting. While tumor epitopes are highly variable, WBC cell-surface markers are well established; applying magnetic-conjugated anti-WBC to this very high-throughput microfluidic cell-separation device can thus exclude the vast majority of WBCs to reveal a small number of untagged CTCs (Figure 1A). Whole-blood labeling using 100 anti-CD45 beads per WBC achieved >103 depletion in normal mice, mice bearing orthotopic tumors, and the KPC mice (Figure 1B).
Affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA; Department of Medicine, Harvard Medical School, Boston, MA 02114, USA.