HIF-1α activates hypoxia-induced PFKFB4 expression in human bladder cancer cells

PFKFB4 is reported to regulate glycolysis by synthesizing fructose-2, 6-bisphosphate (F2,6BP) and has proved to be associated with most malignancies. However, the underlying mechanism for increased PFKFB4 expression in bladder cancer remains unclear. The present study demonstrated that PFKFB4 was overexpressed in bladder cancer tissues. In addition, the expression of PFKFB4 elevated in bladder cancer cells in the hypoxic condition, while in nomoxic condition, the expression of PFKFB4 still very low. Furthermore, we identified the hypoxia-responsive elements (HRE)-D from five putative HREs in the promoter region of PFKFB4 and demonstrated that the HRE-D was transactivated by the HIF-1α in bladder cancer cells. By using the Double-immunofluorescence co-localization assay, we revealed that the HIF-1α expression was associated with PFKFB4 expression in human bladder cancer specimens. Altogether, our study for the first time identified the pivotal role of HIF-1α in the connection between PFKFB4 and hypoxia in bladder cancer, which may prove to be a potential target for the treatment of bladder cancer.