Expression profiling by high throughput sequencing
Summary
T cells are central players in cancer immunotherapy1, yet some of their fundamental properties such as development and migration within tumours remain elusive. The enormous T cell receptor (TCR) repertoire, required for recognising foreign and self-antigens2,3, could serve as lineage tags to track these T cells in tumours4. Here, we obtained transcriptomes of 11,138 single T cells from 12 colorectal cancer (CRC) patients and developed STARTRAC (Single T-cell Analysis by Rna-seq and Tcr TRACking) indices to quantitatively analyse dynamic relationships among 20 identified T cell subsets with distinct functions and clonalities. While both CD8+ effector and ?exhausted? T cells exhibited high clonal expansion, they were independently connected with tumour-resident CD8+ effector memory cells, implicating a TCR-based fate decision. Of the CD4+ T cells, the majority of tumour-infiltrating Tregs showed clonal exclusivity, whereas certain Treg clones were developmentally linked to multiple TH clones. Notably, we identified two IFNG+ TH1-like clusters in tumours, the GZMK+ TEM and CXCL13+ TH1-like clusters, which were associated with distinct IFN-?-regulating transcription factors, EOMES/RUNX3 and BHLHE40, respectively. Only BHLHE40+ CXCL13+ TH1-like cells were preferentially enriched in tumours of microsatellite-instable (MSI) patients, which might explain their favourable response rates to immune-checkpoint blockade. Furthermore, we found IGFLR1 to be highly expressed in both BHLHE40+CXCL13+ TH1-like and CD8+ exhausted T cells and possessed co-stimulatory functions. Our integrated STARTRAC analyses provided a powerful avenue to comprehensively dissect the T cell properties in CRC, which could shed new insights into the dynamic relationships of T cells in other cancers.
Overall design
T cells from CRC patients were sorted, profiled by Smart-seq2 and sequenced on HiSeq4000. Based on FACS analysis, single cells of different subtypes, including CD8+ T cells (CD3+ and CD8+), T helper cells (CD3+, CD4+ and CD25-), and regulatory T cells (CD3+, CD4+ and CD25high) were sorted to perform RNA sequencing. The categories ?""sampleType"" column in the SAMPLES section? contain PTC(CD8+ T cells from peripheral blood), NTC(CD8+ T cells from adjacent normal colonrectal tissues) ,TTC (CD8+ T cells from tumor), PTH(CD3+, CD4+ and CD25- T cells from peripheral blood), NTH(CD3+, CD4+ and CD25- T cells from adjacent normal colonrectal tissues), TTH(CD3+, CD4+ and CD25- T cells from tumor), PTR(CD3+, CD4+ and CD25high T cells from peripheral blood), NTR(CD3+, CD4+ and CD25high T cells from adjacent normal colonrectal tissues), TTR(CD3+, CD4+ and CD25high T cells from tumor), PTY(CD3+, CD4+ and CD25mediate T cells from peripheral blood), NTY(CD3+, CD4+ and CD25mediate T cells from adjacent normal colonrectal tissues), TTY(CD3+, CD4+ and CD25medate T cells from tumor), PP7(CD3+, CD4+ T cells from peripheral blood), NP7(CD3+, CD4+ T cells from adjacent normal colonrectal tissues), TP7(CD3+, CD4+ T cells from tumor).
Raw data access provided at: European Genome-phenome Archive (EGA) under accession EGAS00001002791