Figure 6.

Human ES2 ovarian cancer TICs express PD-L1 that regulates self-renewal, immune-independent tumorigenicity and SOX2. PD-L1 (a) or PD-1 (b) expression in control (ctrl) and PD-L1^lo ES2 TIC by flow cytometry. (c) Percent of ALDH^hi TIC by flow cytometry of cultured cells. P-values, unpaired t-test. (d) Representative photomicrographs of ES2 tumorospheres. Bar equals 100 μm. Quantification of the size (e) and number of spheres per field (f). P-values, unpaired t-test. (g) Representative photomicrographs of tumorospheres formed by CD44⁺CD24⁻ TICs from control or PD-L1^lo clone 1 after 14 days, and their diameter (h). (i) Survival curve of NSG mice injected with 20 000 ALDH^hi TICs indicated (n=3–5 per group). Median survival (days) in boxes by individual curves. P-value, log-rank test. (j) SOX2 expression by quantitative PCR from ALDH^hi TICs and total cultures. Fold changes by ΔΔCT between TICs and respective total cultures. These fold changes were compared between control and PD-L1^lo clones. All P-values calculated, unpaired t-test.