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® 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 ~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.