MicroRNA‑451 inhibits neuroblastoma proliferation, invasion and migration by targeting macrophage migration inhibitory factor.

Neuroblastoma (NB) is the most prevalent type of extracranial solid tumour in young children. To improve current understanding of the mechanisms, which modulate cancer cell proliferation, invasion and migration, investigations have focused on microRNAs (miRs), a class of small non‑coding RNAs, which post‑transcriptionally regulate gene expression during various crucial cell processes. The present study aimed to investigate the role of miR‑451 in NB. Human NB tissue and adjacent normal tissue were surgically removed, and the expression of miR‑451, and development and pathological characteristics of NB were investigated. The expression of miR‑451 was reduced in the NB tissue, compared with that in the adjacent tissue, and correlations between the reduction in miR‑451 and unfavourable variables included tumour size (P=0.0081), differentiation (P=0.0217), lymph node metastasis (P=0.0489), tumour‑node‑metastasis stage (0.0220) and distant metastases (P=0.0201). Transfection of the SK‑N‑SH and GI‑LA‑N NB cell lines with miR‑451 inhibited cell growth, invasion and migration. Furthermore, the present study demonstrated that macrophage migration inhibitory factor (MIF) was regulated directly by miR‑451 and was a critical mediator of the biological effects of miR‑451 in NB. The re‑expression of MIF markedly reversed the carcinogenic inhibitory property of miR‑451. These data provide a more detailed understanding of the essential role of miR‑451 in NB, which relies on regulation of the expression of MIF.