Fig. 4: Fumarate-induced PD-L1 expression depends on HIF-1α/p300/PKM2 transcriptional complex.

A, B Western blot and qRT-PCR analyses were performed to evaluate the PD-L1 levels in RCC10 and RCC4 cells treated with DMF/FHIN1, both in the absence and presence of 20 μM A485 or 100 nM CCS1477, an inhibitor of p300. ***P < 0.001, ****P < 0.0001. C, D Western blot and qRT-PCR analyses were performed to assess PD-L1 levels in RCC10 and RCC4 cells that were treated with DMF/FHIN1, with or without the addition of 0.3 μM PKM2-IN-1 or 1 μM Shikonin, an inhibitor of PKM2. ***P < 0.001, ****P < 0.0001. E, F Western blot analyses were performed to assess the PD-L1 levels in RCC4 cells treated with FHIN1, both in the absence and presence of 20 μM A485 or 100 nM CCS1477, an inhibitor of p300. G, H Western blot analyses were performed to assess PD-L1 levels in RCC4 cells that were treated with FHIN1, with or without the addition of 0.3 μM PKM2-IN-1 or 1 μM Shikonin, an inhibitor of PKM2. I After pre-treatment with or without YC-1, CCS1477, and PKM2-IN-1, DMF-treated RCC4 cells were cocultured with activated T cells for 48 h, followed by crystal violet staining. The quantification was shown on the Right. Data represent mean ± SD, n = 3. **P < 0.01, ***P < 0.001.