However, due to relative lower incidence (Katoh et al. Preventing or attenuating the progression of bone metastasis is critical to improve QoL and prognosis of patients with bone metastasis of CRC. Radiation and pathologic fractures can affect 45% and 10% patients with bone metastasis of CRC, respectively (Santini et al. Besides to death, complications, including bone-associated pain, pathological fractures, can influence quality of life (QoL) in patients with CRC significantly. It was reported median time to first skeletal-related event (SRE) was 2 months and median survival in CRC patients was only 7 months since they were diagnosed with bone metastasis, indicating bone metastasis is an early event in CRC and leads to a poorer prognosis (Santini et al. Overexpression of miR-325-3p efficiently decreased the osteoclast number and attenuated bone resorption in bone metastasis of CRC.īone is one of metastatic sites in colorectal cancer (CRC). MiR-325-3p can prevent osteoclast formation through targeting S100A4 in OCPs. Treatment with miR-325-3p can preserve trabecular area in bone metastasis of CRC. Overexpression of miR-325-3p inhibited the osteoclastogenesis of OCPs and it can be reversed after transfection with plasmid containing S100A4. By luciferase activity assay, S100A4 was the target gene of miR-325-3p and the protein level of S100A4 in OCPs upregulated in CRC microenvironment. MiR-325-3p downregulated in OCPs in CRC microenvironment both in vivo and in vitro. Western blot analysis was performed to examine the protein level of S100A4 in OCPs after interfered by agomiR-325-3p or antagomir-325-3p cultured in CM or not. Conditioned medium from CT-26 cells was collected to stimulate the OCPs during osteoclastogenesis induced by RANKL and M-CSF in vitro.

Dual-luciferase reporter system was utilized to identify the direct target of miR-325-3p. Real-time PCR was conducted to test the RNA level of miR-325-3p and mRNA levels of TRAP and Cathepsin K in osteoclast precursors (OCPs).

Safranin O and Fast Green staining examined the changes of trabecular area and TRAP staining examined the osteoclast number in bone metastasis of CRC. AgomiR-325-3p or antagomir-325-3p were injected in tail-veins of Balb/c mice to interfere the osteoclastogenesis and bone metastasis of CRC. MethodsĬT-26 cells were injected into tibias to establish bone metastatic model of CRC in vivo. To investigate effect of microRNA-325-3p (miR-325-3p) on bone metastasis of colorectal cancer (CRC) and the precise role on osteoclastogenesis.

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