The hypoxia-inducible factor-1 regulates the microRNA185 expression through binding to hypoxia response elements sequence 2.

This study aimed to investigate the interaction and regulatory mechanism of microRNA185 (miR185) and hypoxia-inducible factor-1 (HIF-1) in pancreatic cancer. The significance of miR185 on the clinicopathologic characteristics and prognosis was further explored. qRT-PCR and immunohistochemistry examined miR185 and HIF-1 expression of tumor tissues. Western blot analyzed HIF-1 protein expression. We regulated HIF-1 via transfection to observe the impact of HIF-1 on miR185 expression. ChIP sequencing and dual luciferase identified binding sites of HIF-1 and miR185. MiR185 expression was significantly higher in pancreatic tumors. MiR185 closely associated with tumor size, pTNM stage, lymph node, and perneural invasion. After hypoxic culture, both HIF-1 and miR185 expression of MiaPaCa2 and AsPc1 cells increased significantly. Up- or down-regulating HIF-1 expression via transfection leads to synchronous alteration of miR185. In ChIP sequencing, only the HRE2 (-938 bp) was significantly brighter under hypoxia among four hypoxia response elements' (HREs) sequence of miR185 promoter. After pGL3-miR185 and HIF-1 over-expressing plasmids co-transfect the MiaPaCa2 cells, its relative expression of bioluminescence increased. MiR185 expression was significantly higher in tumor tissues and closely associated with the clinical features of pancreatic cancer. Expression of HIF-1 in pancreatic cancer cells increased in hypoxia. HIF-1 may bind to HRE2 of miR185 and initiate its transcription.