Lineage tracing and targeting of IL17RB ⁺ tuft cell-like human colorectal cancer stem cells

Abstract

Cancer stem cell (CSC)-specific markers may be potential therapeutic targets. We previously identified that Dclk1, a tuft cell marker, marks tumor stem cells (TSCs) in mouse intestinal adenomas. Based on the analysis of mouse Dclk1 + tumor cells, we aimed to identify a CSC-specific cell surface marker in human colorectal cancers (hCRCs) and validate the therapeutic effect of targeting it. IL17RB was distinctively expressed by Dclk1 + mouse intestinal tumor cells. Using Il17rb-CreERT2-IRES-EGFP mice, we show that IL17RB marked intestinal TSCs in an IL13-dependent manner. Tuft cell-like cancer cells were detected in a subset of hCRCs. In these hCRCs, lineage-tracing experiments in CRISPR-Cas9-mediated IL17RB-CreERT2 knockin organoids and xenograft tumors revealed that IL17RB marks CSCs that expand independently of IL-13. We observed up-regulation of POU2F3, a master regulator of tuft cell differentiation, and autonomous tuft cell-like cancer cell differentiation in the hCRCs. Furthermore, long-term ablation of IL17RBexpressing CSCs strongly suppressed the tumor growth in vivo. These findings reveal insights into a CSC-specific marker IL17RB in a subset of hCRCs, and preclinically validate IL17RB + CSCs as a cancer therapeutic target.C ancer stem cells (CSCs), capable of self-renewal and giving rise to progeny cells in cancers, have attracted attention as promising targets for anticancer therapeutics. The traditional xenotransplantation assays used to investigate the properties of CSCs have technical and conceptual limitations (1). Recent studies have shown that leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) marks CSCs in human colorectal cancers (hCRCs) in vivo by lineage tracing of LGR5-CreERT2 knockin hCRC organoids generated by CRISPR-Cas9-mediated gene editing (2, 3). Because most of the CSC markers are also expressed by normal stem cells (4-7), long-term CSC targeting may disrupt normal tissue homeostasis [e.g., liver injury after long-term LGR5-targeting (8)], whereas short-term CSC targeting leads to tumor regrowth (2,9). Hence, identification of CSC-specific markers is essential. We previously showed that Dclk1, a differentiated tuft cell marker in normal intestine, marks tumor stem cells (TSCs) in mouse intestinal adenomas by lineage-tracing experiments (10). However, whether DCLK1 marks CSCs in hCRCs has not been elucidated by in vivo lineage tracing of the tumors. Furthermore, feasible strategies to target DCLK1 + cells are necessary to realize a novel CSC-targeted therapy for hCRCs. Identification of a specific cell surface marker in Dclk1 + cells can facilitate the sorting analysis of Dclk1 + tumor cells and can also have the potential for future antibody therapeutics.The IL-17 receptor family includes five members (IL17RA to IL17RE) (11). The heterodimer of IL17RA and IL17RC serves as a receptor for IL-17A and IL-17F to mediate Th17 immune response, and the heterodimer of IL17RA and IL17RB serves as a receptor for IL-25 to mediate Th2 immune response (12).Recent studies showed that...

Acetylcholine From Tuft Cells: The Updated Insights Beyond Its Immune and Chemosensory Functions

“…Furthermore, Goto et al (2019) found IL17RB, a tuft cell marker, is distinctively expressed by DCLK1 + mouse intestinal tumor cells and regulates the function of tuft cell-derived cancer stem cell. The expression of IL17RB was then proven to be a potential marker for the lineage tracing of human colorectal cancer stem cells ( Goto et al, 2019 ). However, in human pancreas, DCLK1, a tuft cell marker in rodents, failed to co-localize with ChAT + cholinergic tuft cells ( Schütz et al, 2019 ).…”

“…With increasing evidence highlighting the role of ACh as an autocrine and paracrine hormone, cholinergic targets have drawn widespread attention in pulmonary diseases ( Meurs et al, 2013 ; Voisin et al, 2017 ), Hirschsprung’s disease ( O’Donnell et al, 2020 ) and cancers ( Westphalen et al, 2014 ; Schütz et al, 2015 ; Pozo et al, 2018 ; Friedman et al, 2019 ; Goto et al, 2019 ). Tuft cells, considered as a crucial non-neuronal ACh source, have also been discussed in several disease models.…”

Role of Muscarinic Acetylcholine Signaling in Gastrointestinal Cancers

“…In addition, in vitro co-culture experiments showed that nerves fail to support organoid growth in the absence of Dclk1+ tuft cells, suggesting that Dclk1+ cells are involved in the integration of neuronal signals in the epithelium [76]. More recently, Goto et al identified interleukin 17 receptor B (IL17RB) as a cell-specific marker of tuft cells, and showed that IL17RB regulates tuft cell-derived cancer stem cell function and could be a therapeutic target [77].…”

Bmi1 Severs as a Potential Tumor-Initiating Cell Marker and Therapeutic Target in Esophageal Squamous Cell Carcinoma

“…However, traditional transplantation assays often disrupt the native microenvironment of TICs and led to alteration of TIC characteristics [ 16 ]. To avoid the shortcomings of these assays, lineage tracing of genetically labeled cells has been used to identify TICs in vivo [ 17 – 19 ].…”