EPAS1 and infection: As shown in Fig 6A, infection with HIF-1α shRNA lentivirus (HIF-1α-shRNA-1 and HIF-1α-shRNA-2) specifically prevented HIF-1α expression, but not HIF-2α expression, in RCC4 cells, which was further confirmed by detecting LDHA protein (a specific downstream target of HIF-1α [32]) (Fig 6A).