Fig. 1: Let-7 promotes CTL anti-tumor response and changes the expression of key genes involved in CD8 T cell differentiation.

a, b Experimental design (a, top), tumor growth curves (a, bottom) and Kaplan–Meier survival curves (b) of WT mice s.c. injected with B16^gp33 tumor cells and adoptively transferred with P14⁺ CTLs from either WT (n = 5), lin28Tg (n = 5) or let-7Tg (n = 4) mice. Gray color represents control group that received no CTLs (n = 5). c–h, RNA-seq of day 5 P14⁺ CTLs from either WT, lin28Tg or let-7Tg mice. Data are from one RNA-seq analysis comprised of three biological replicates per group. c Principal component (PC) analysis of all differentially expressed genes (DEGs). d Volcano plots of all upregulated and downregulated DEGs in lin28Tg (left) and let-7Tg (middle) CTLs in comparison to WT CTLs and let-7Tg in comparison to lin28Tg CTLs (right). e Cluster analysis of top 177 upregulated and downregulated DEGs. f Enrichment for terminal differentiation signature genes in lin28Tg P14⁺ CTLs and memory signature genes in let-7Tg P14⁺ CTLs. FDR false discovery rate, NES normalized enrichment score. g, h Heatmap of terminal differentiation genes (g) and memory differentiation genes (h) in P14⁺ CTLs. Red color represents the genes for inhibitory receptors (g) and stem cell signature genes (h). i, j FACS of the expression of proteins (left) and quantitative RT-PCR analysis of the expression of genes (right) involved in terminal differentiation (i) or memory formation (j) in WT, let-7Tg, and Lin28Tg CTLs. Data i, j are the means ± s.e.m. of technical triplicates; P-values were determined using a two-tailed unpaired Student’s t-test (i, j), two-way ANOVA with Sidak’s multiple comparison test (a) and log-rank Mantel-Cox test (b). Data represent two (a, b) or three (i, j) independent experiments. Source data for a, b, i, j are provided as a Source Data file.