biostudies-literatureRivello FRadboud University NijmegenGellderland Provinceeaaz3849https://www.ebi.ac.uk/biostudies/studies/S-EPMC7527228biostudies-literatureUnknown6(40)Despite their important role in metastatic disease, no general method to detect circulating stromal cells (CStCs) exists. Here, we present the Metabolic Assay-Chip (MA-Chip) as a label-free, droplet-based microfluidic approach allowing single-cell extracellular pH measurement for the detection and isolation of highly metabolically active cells (hm-cells) from the tumor microenvironment. Single-cell mRNA-sequencing analysis of the hm-cells from metastatic prostate cancer patients revealed that approximately 10% were canonical EpCAM⁺ hm-CTCs, 3% were EpCAM^- hm-CTCs with up-regulation of prostate-related genes, and 87% were hm-CStCs with profiles characteristic for cancer-associated fibroblasts, mesenchymal stem cells, and endothelial cells. Kaplan-Meier analysis shows tScience advancesProbing single-cell metabolism reveals prognostic value of highly metabolically active circulating stromal cells in prostate cancer.PMC7527228Radboud Nanomedicine AllianceProeftuin NanomedicineMehra NSmits MMatula KHuck WTSRivello FPiruska AfalseProbing single-cell metabolism reveals prognostic value of highly metabolically active circulating stromal cells in prostate cancer.Despite their important role in metastatic disease, no general method to detect circulating stromal cells (CStCs) exists. Here, we present the Metabolic Assay-Chip (MA-Chip) as a label-free, droplet-based microfluidic approach allowing single-cell extracellular pH measurement for the detection and isolation of highly metabolically active cells (hm-cells) from the tumor microenvironment. Single-cell mRNA-sequencing analysis of the hm-cells from metastatic prostate cancer patients revealed that approximately 10% were canonical EpCAM⁺ hm-CTCs, 3% were EpCAM^- hm-CTCs with up-regulation of prostate-related genes, and 87% were hm-CStCs with profiles characteristic for cancer-associated fibroblasts, mesenchymal stem cells, and endothelial cells. Kaplan-Meier analysis shows t2020-01-01T00:00:00Z2020 Sep2026-05-05T00:44:26.423Z2020-10-29T08:12:22ZS-EPMC75272283299888910.1126/sciadv.aaz3849