Fig. 3: TP53 transcriptionally activates PHKG2 to suppress nuclear NRF2 expression in vitro and in vivo. | Cell Death & Disease

Fig. 3: TP53 transcriptionally activates PHKG2 to suppress nuclear NRF2 expression in vitro and in vivo.

From: Transcriptional activation of PHKG2 by TP53 promotes ferroptosis through nuclear export of NRF2 in head and neck squamous cell carcinoma

Fig. 3

JASPAR analysis predicts potential TP53 binding sites within the PHKG2 promoter region (A). ChIP-PCR experiments verified direct binding of TP53 to the PHKG2 promoter, with significantly increased enrichment observed upon TP53 overexpression (B). Dual-luciferase reporter assays confirmed TP53-mediated transcriptional activation of PHKG2 (C). qRT-PCR analysis indicated that TP53 positively regulated PHKG2 mRNA levels, without affecting NRF2 mRNA expression (*p < 0.05, **p < 0.01, ***p < 0.001) (D, E). Western blot analysis revealed that TP53 upregulated PHKG2 protein expression and decreased nuclear NRF2 levels, while total NRF2 protein remained unchanged (F). Confocal microscopy confirmed decreased nuclear and increased cytoplasmic NRF2 following PHKG2 overexpression (G). Xenograft mouse models showed PHKG2 overexpression significantly inhibited tumor growth, whereas administration of the TP53 inhibitor Pifithrin-α reversed this effect, leading to increased tumor size and enhanced Ki67 expression (**p < 0.01, ***p < 0.001) (H–J). qRT-PCR analysis showing that TP53 and PHKG2 mRNA levels are elevated in tumors from the oe-PHKG2 group. Treatment with the TP53 inhibitor Pifithrin-α partially reduces these increases, but does not completely abrogate the upregulation (**p < 0.01, ***p < 0.001) (K, L). NRF2 mRNA levels remained unaffected (M). Western blot further confirmed reduced nuclear NRF2 protein levels upon TP53-mediated PHKG2 activation (N).

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