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. Author manuscript; available in PMC: 2023 May 3.
Published in final edited form as: Cancer Res. 2023 May 2;83(9):1426–1442. doi: 10.1158/0008-5472.CAN-22-3000

Figure 6.

Figure 6.

Cystine is a major contributor to the cysteine pool in tumors. A, Analysis of the fraction labeling in cysteine, γ-glutamylcysteine, and glutathione in liver tissues (N=9), HCC tumors (N=9), lung tissues (N=10), Nrf2WT LUAD tumors (N=16), Nrf2D29H LUAD tumors (N=10), pancreas tissues (N=3), PDAC tumors (N=12), and their matched serum from normal control mice for HCC (N=6), HCC (N=7), normal control mice for PDAC (N=3), PDAC (N=6), normal control mice for LUAD (N=5), Nrf2WT LUAD (N=8), and Nrf2D29H LUAD serum (N=5) following infusion with 13C6-cystine. B, Total signal of glutathione in the tissues from A. C, Total signal of cysteine in the tissues from A. For A-C, data are presented as mean ± SD. N.D., not detected. D, Immunoblots of cystine/glutamate antiporter (xCT), glutamate-cysteine ligase catalytic subunit (GCLC), glutamate-cysteine ligase modifier subunit (GCLM), and glutathione synthetase (GSS) for each tissue. HSP90 was used for the loading control. *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001. Cys, cysteine; GSH, glutathione; γ-Glu-Cys, γ-glutamylcysteine.