Fig. 3.

Glutamine and glucose deprivation increase utilization of the other substrate and increase tumor PD-L1 expression. A [¹³C₃] pyruvate/[¹³C₆] glucose in cells incubated in [U-¹³C₆] glucose. B Lactate production by YUMM1.7 and YUMMER1.7 melanoma cells. C Oxygen consumption during a mitochondrial stress test. D–F Contribution of ¹³C glucose, glutamine, and palmitate to citrate in YUMM1.7 and YUMMER1.7 cells. G, H Impact of glucose and glutamine deprivation on YUMM1.7 and YUMMER1.7 PD-L1 expression, measured by flow cytometry. In all panels, comparisons within cell lines were performed by ANOVA with Tukey’s multiple comparisons test, and comparisons between cell lines by the 2-tailed unpaired Student’s t test. *P<0.05, **P<0.01, ****P<0.0001. a.u. arbitrary unit