MicroRNA‑1 inhibits the proliferation of Chinese sika deer‑derived cartilage cells by binding to the 3'-untranslated region of IGF‑1.

Insulin-like growth factor-1 (IGF-1) is critical in the proliferation and regeneration of Chinese sika deer antler cells. The regulation of IGF-1 is complex and remains unclear. In the present study, miRNA GeneChip (R) and TargetScan Human software were used to identify microRNA-1 (miR-1), which binds to the 3'-untranslated region (3'UTR) of IGF-1. An miR-1 mimic was transfected into antler cartilage cells in order to induce the overexpression of miR-1. The expression levels of miR-1 in antler cartilage cells were determined by quantitative polymerase chain reaction (qPCR). A high-throughput luciferase reporter screen was used to demonstrate the potential regulation of IGF-1 by miR-1. miR-1 suppressed the luciferase activity of the pmiR-IGF-1 by similar to 50% compared with the negative control (NC). An MTT assay and cell cycle analyses confirmed that the overexpression of miR-1 significantly inhibited the proliferation of cartilage cells (P<0.05). Furthermore, western blot analysis revealed that overexpressed miR-1 downregulated the protein levels of IGF-1. The 3'UTR of IGF-1 was found to have an miR-1 combining site, which allowed the inhibition of IGF-1 protein expression, as demonstrated by a luciferase reporter assay, and miR-1 was shown to be an important and effective means of regulating IGF-1. In conclusion, miR-1 downregulated the protein expression of IGF-1 by directly targeting the 3'UTR of IGF-1. miR-1 may be crucial for inhibiting the proliferation of deer antler cartilage cells. Our findings provided the evidence for the first time that miR-1 directly regulates the expression of IGF-1 by directly targeting its 3'UTR.