FIGURE 2 from Inhibition of Microsomal Prostaglandin E2 Synthase Reduces Collagen Deposition in Melanoma Tumors and May Improve Immunotherapy Efficacy by Reducing T-cell Exhaustion

In vivo tumor growth assessment and RNA-seq characterization of murine BrafV600E melanoma cells with ptgs1, ptgs2, or ptges KO. A, Cell proliferation assay in scramble, ptgs1-KO, ptgs2-KO, and ptges-KO murine BrafV600E melanoma cells. Results represent the fold change relative to the OD value of baseline levels at time 0 for each cell (0, 24, 48, and 72 hours after culture; n = 6). Differences between two groups were analyzed by repeated measures one-way ANOVA, followed by Tukey post hoc test. B, Left, Tumor volume measurement at indicated timepoints for scramble, ptgs1-KO, ptgs2-KO, and ptges-KO cells. A total of 1 × 106 cells per mouse were injected subcutaneously into the flanks of C57BL/6J mice: n = 8 mice each for scramble, ptgs1-KO, and ptgs2-KO groups, and n = 7 for ptges-KO group. Differences in tumor volume between two groups were analyzed by repeated measures one-way ANOVA, followed by Tukey post hoc test. B, Right, Tumor volumes for individual mice in each group are shown. C, Tumor-free survival (tumor volume 3) was estimated using the Kaplan–Meier method and compared using the log-rank test. D, Heat map showing the unsupervised hierarchical clustering of the mRNA levels (Reads Per Kilobase Million [RPKM]) of eight collagen-related genes across scramble, ptgs1-KO, ptgs2-KO, and ptges-KO cells. RNA was extracted from three different subclones in each cell line. E, Spearman correlation values between immune-suppressive markers and collagen-related genes in melanoma samples from TCGA-SKCM dataset. Graph values represent mean ± SD. **, P < 0.01. N.S., not statistically significant.