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The aim of this research was to explore the effects and signaling pathway of ultraviolet-B (UVB) irradiation on the expression of hypoxia-inducible factor 1α (HIF-1α) and transferrin receptor (TfR).HIF-1α protein was measured by Weste blot method.Expressions of epidermal growth factor receptor (EGFR),phosphor-EGF-R and TfR after UVB irradiation were determined with flow cytometry.After UVB irradiation,mRNA levels of HIF-1α and TfR were detected by real time-PCR.Results showed that compared with control groups,UVB was able to induce HIF1α and TfR protein expression in a dose- and time-dependent manner in HaCat cells (P ＜ 0.05).TfR mRNA was expressed in a dose-dependent manner and reached a peak at the 8th hour in HaCat cells (P＜0.05) whereas HIF-1α mRNA expression was not affected by UVB treatment (P＞0.05).The EGFR/PI3K/AKT signaling pathway was required for the induction of HIF-lcx and TfR expression induced by UVB.UVB induced activation of EGFR in HaCat cells and EGFR regulated expression of TfR and HIF-1α.EGFR (-/-) MEF did not increase the HIF 1 expression following UVB irradiation (P＞0.05).In contrast,EGFR (+/+) MEF strongly enhanced HIF 1α expression after UVB irradiation (P ＜ 0.05).PD153035,a selective inhibitor of EGFR tyrosine kinase,inhibited the TfR protein expression in UVB-treated cells in a dose-dependent manner (P＜0.05).PI3K inhibitors,LY294002 and wortmannin,inhibited HIF-1α and TfR expressions induced by UVB (P ＜ 0.05).The DEC1 (-/-) Ha-Cat cells did not increase their TfR and HIF-1α expressions following UVB irradiation (P＞0.05).In contrast,DEC1 (+/+) HaCat cells strongly enhanced TfR and HIF-1α protein expression after UVB irradiation (P＜0.05).We conclude that UVB induces TfR and HIF-1α expressions via EGFR/PI3K/AKT/DEC1 signaling pathway.