Table 2.
Single-cell analysis on fibroblastic cells of CRC.
| Purpose | Analysis | Model/Study Design | Finding | Ref. |
|---|---|---|---|---|
| Studying CRC cellular heterogeneity | scRNA-Seq | Human model | Two distinct subtypes of CAFs (CAF-A and CAF-B) were identified. CAF-B cells showed expression of cytoskeletal genes and other associated markers of activated myofibroblasts, whereas expression of ECM-related genes was found in CAF-A. | [120] |
| Studying genomic changes of CRC stromal cells | Single-cell multi-omics sequencing | Human model | Higher proportions of aneuploid fibroblasts in tumours compared to those in normal tissues, with significant clonal expansion of fibroblasts with an extra copy of chromosome 7. | [121] |
| Single-cell analysis of colon biopsy | Droplet-based scRNA-Seq, SMART-Seq2 on colonic spheroids | Human model—normal and UC patients | Using clustering, 51 cell subsets were identified (epithelial: 15; fibroblast: 8; endothelial: 4; glial: 1; myeloid: 7; B: 4; T: 10 (CD4+ Tconv, Tregs, CD8+, and γδ); innate lymphoid cell (ILC): 1; NK cell: 1. The inflammatory fibroblast (IAF) subset expresses markers of CAFs unique to UC, suggesting an IAF expansion of CRC. IAFs are composed of WNT2B+ and WNT5B+ subsets. | [122] |
| Single-cell transcriptional profiles study | SmartSeq2 | Animal (murine) model—comparison between fibroblasts and vascular cells in muscular organs | Subpopulation of fibroblast cells (Tnc+ Cd34−) which are localised at the surface epithelium whereas Tnc− Cd34+ fibroblasts were found deeper down in the lamina propria and in the muscularis mucosa. Differential expression in BMP and WNT signalling pathways was also reported between the two populations. | [123] |
| Prediction of prognosis and therapeutic responses in CRC | GEO single-cell transcriptome, qPCR analyses | Bio-informatics analysis | Established the correlation between greater CAF risk scores with poor prognosis in CRC samples. Those with higher CAF risk scores indicated lower response to immunotherapy, but better sensitivity to conventional chemotherapeutics. | [83] |
| Classification of tumour cells and clinical stratification | Single-cell resolution transcriptomic analysis | Bio-informatics analysis | Identification of the transcriptional signature of specific subtypes of colorectal CAF (CAF-S1 and CAF-S4) that significantly indicate stratification of a patient’s survival. Two CAF-S1 subpopulations, ecm-myCAF and TGFß-myCAF, are linked to primary resistance to immunotherapies. | [124] |
| Association between presence of IL-11-expressing fibroblasts and CRC prognosis | Transcriptome analysis on human cancer database | Bio-informatics analysis | Expression of fibroblast markers and genes implicated in cell growth and repair in IL-11+ cells. Expression of genes enriched in IL-11+ fibroblasts is increased in colorectal tumours and associated with lower recurrence-free survival. | [125] |
| Dissecting ITH of CRC | Single-cell exome and transcriptome sequencing | Animal (mouse) model and metastatic human CRC model | Demonstrated the dynamics of ITH of CRC. The emergence of transcriptional subpopulations which lead to increased ITH may be vital for adaptation to drastic changes in the microenvironment when malignant cells have gained sufficient genetic alterations at the advanced stage of tumourigenesis. | [126] |
GEO: Gene Expression Omnibus; IAF: inflammation-associated fibroblast; IL: Interleukin; qPCR: quantitative real-time polymerase chain reaction.