Abstract:
Background and Objective: Formaldehyde (FA) exposure is a recognized environmental risk factor for head and neck squamous cell carcinoma (HNSCC), often driving epithelial malignant transformation via enhanced glycolysis. Fisetin, a natural flavonoid, exhibits potent anti-tumor properties; however, its role and underlying mechanisms in FA-induced carcinogenesis remain elusive. This study aims to investigate the reversing effects of Fisetin on FA-induced malignant transformation in head and neck epithelial cells, specifically focusing on the E2F1/AREG signaling axis and glycolytic reprogramming.
Methods and Results: FA-induced malignant transformation models of head and neck epithelial cells were established both in vitro and in vivo. Fisetin treatment dose-dependently inhibited FA-induced cell proliferation, colony formation, invasion, and in vivo tumorigenicity, effectively reversing the malignant phenotype. Metabolic flux analyses revealed that FA exposure significantly increased the extracellular acidification rate (ECAR), glucose consumption, and lactate production. Remarkably, Fisetin substantially reversed these glycolytic enhancements. Mechanistically, FA exposure activated the transcription factor E2F1, which subsequently transcriptionally upregulated amphiregulin (AREG); Fisetin markedly suppressed the activation of this E2F1/AREG axis. Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays confirmed that E2F1 directly bound to the AREG promoter and enhanced its transcription. Crucially, functional rescue experiments demonstrated that overexpression of E2F1 or AREG significantly abrogated Fisetin-mediated glycolysis inhibition and partially restored the malignant phenotype, whereas E2F1 knockdown phenocopied the effects of Fisetin.
Conclusion: Our findings reveal that Fisetin effectively reverses FA-induced malignant transformation in head and neck epithelial cells by inhibiting E2F1/AREG-mediated glycolytic reprogramming. This study not only provides a novel metabolic mechanism insight into FA-associated carcinogenesis but also highlights Fisetin as a promising therapeutic agent for the targeted intervention of HNSCC.
