Astragalus Polysaccharides Alleviate Lung Adenocarcinoma Bone Metastases by Inhibiting the CaSR/PTHrP Signaling Pathway
Abstract Background: To expore the possible effect and mechanism of Astragalus Polysaccharide (APS) on bone metastasis of lung adenocarcinoma.Methods: The culture media of osteoclast (OC) precursor cells, osteoblasts (OBs) and A549 cells were constructed respectively. TRAP staining was used to detect the effect of APS on OC differentiation. Alizarin red staining was used to detect the effect of APS on OB differentiation. The expressions of OC differentiation related proteins and OB specific proteins were detected by Western blotting. The effects of APS on the proliferation and migration of A549 cells were detected by CCK-8 and Transwell assay, respectively. The effect of APS on A549 induced apoptosis was analyzed by flow cytometry. The expression of calcium sensing receptor (CaSR) / parathyroid hormone-related protein (PTHrP) signal pathway related proteins was detected by Western blotting. The mouse model of bone metastasis of lung adenocarcinoma was established. The occurrence of bone metastasis of lung adenocarcinoma in mice was verified by micro CT. The inhibition of APS on bone metastasis and the promotion of tumor cell apoptosis were detected by HE staining and TUNEL assay.Results: APS inhibited the formation of receptor activator of nuclear factor-κB ligand (RANKL) induced OCs and promoted the differentiation of OBs in a concentration dependent manner. APS inhibited RANKL induced OC differentiation and the expression of related proteins, and promoted OB differentiation and the expression of related proteins. APS inhibited the proliferation and migration of A549 cells and promoted apoptosis in a concentration dependent manner. APS may inhibit the proliferation and invasion of A549 cells by inhibiting CaSR / PTHrP signaling pathway, and inhibit the expression of CaSR / PTHrP signaling pathway related proteins. In vivo experiments confirmed that APS inhibited bone metastasis of lung adenocarcinoma.Conclusions: APS can inhibit the proliferation and invasion of lung adenocarcinoma cells by inhibiting the CaSR / PTHrP pathway, and then affect the balance of OCs and OBs in the bone microenvironment, so as to protect the bone metastasis of lung adenocarcinoma.