Functions Of Periostin In Bone Metastasis Of Mouse Breast Cancer

Breast cancer is a disease that is prone to metastasis and occurs mostly in a female population.Bone metastases occur in 65-80%of patients with metastatic breast cancer.The consequences of bone metastases include pathological fractures,pain,hypercalcemia,spinal cord and nerve compression symptoms,which seriously affect people's quality of life.Despite significant advances in bone metastasis research over the past few decades,bone metastases remain incurable.Here,we injected breast cancer cells 4T1 into the left ventricle of wild-type BALB/c mice to generate bone metastasis of mouse breast tumor model.The expression of periostin is significantly increased in the bone metastatic tissues of breast cancer.We used periostin-knockout mice and further found that knockout of periostin inhibits bone metastasis of mouse breast cancer cells by BLI imaging assay.Moreover,we found that knockout of periostin can reduce the degree of bone damage in bone metastatic mice by PET-CT assay.We further used Trap staining and found that the number of osteoclasts in the periostin-knockout mice with bone metastases is significantly less than that of wild-type mice with bone metastases.Furthermore,we induced the differentiation of Raw264.7 cells into osteoclasts in vitro and found that periostin can promote the differentiation of Raw264.7 cells into osteoclasts,indicating that periostin can inhibit the maturation and differentiation of osteoclasts during bone metastasis of breast cancer.This study is of great significance to further explore how to inhibit the development of bone metastasis through inhibiting the function of periostin,which will provide an important experimental basis and a new target for the prevention and treatment of breast cancer with bone metastasis.