Keratin Profiling by Single-Cell RNA-Sequencing Identifies Human Prostate Stem Cell Lineage Hierarchy and Cancer Stem-Like Cells.

Single prostate stem cells can generate stem and progenitor cells to form prostaspheres in 3D culture. Using a prostasphere-based label retention assay, we recently identified keratin 13 ()-enriched prostate stem cells at single-cell resolution, distinguishing them from daughter progenitors. Herein, we characterized the epithelial cell lineage hierarchy in prostaspheres using single-cell RNA-seq analysis. Keratin profiling revealed three clusters of label-retaining prostate stem cells; represents quiescent stem cells (, , , and enriched), while and represent active stem and bipotent progenitor cells ( enriched). Gene set enrichment analysis revealed enrichment of stem and cancer-related pathways in . In non-label-retaining daughter progenitor cells, three clusters were identified; represents basal progenitors ( enriched), while and represent early and late-stage luminal progenitors, respectively ( enriched). Furthermore, MetaCore analysis showed enrichment of the "cytoskeleton remodeling-keratin filaments" pathway in cancer stem-like cells from human prostate cancer specimens. Along with common keratins () in normal stem cells, unique keratins () were enriched in cancer stem-like cells. Clarification of these keratin profiles in human prostate stem cell lineage hierarchy and cancer stem-like cells can facilitate the identification and therapeutic targeting of prostate cancer stem-like cells.