In vitro and in vivo studies of antiosteosarcoma activities of formononetin

Osteogenic sarcoma (OGS) is a primary bone cancer, characterized by aggressive neoplasm from mesenchymal oncogenesis. However, the clinical therapeutic regimen against OGS is limited. Therefore, potential medication warrants to be further developed. Our previous study indicates that formononetin (FN) exerts effective pharmacological activity against OGS. This study aimed to further decipher the molecular mechanism behind this benefit. Patients with OGS were recruited for clinical data assay and immunoassay. Human OGS cell line (U2OS) and tumor-bearing nude mice were subjected to a battery of biochemical analyses and immunoassays for integrative evaluation of FN-exerted anti-OGS effects. In human data, OGS samples showed increased expressions of ER alpha, p-PI3KCA(Tyr317), and p-AKT (Ser473) proteins, followed by notably upregulated miR-375 content in comparison with that in OGS-free. In addition, FN-treated U2OS cells showed inhibited cell proliferation, elevated lactic dehydrogenase production and lowered endogenous miR-375 level in cells. Further, reduced immunopositive cells of Ki-67, p-PI3KCA (Tyr317), and p-AKT (Ser473) were observed by the treatments of FN, while the intracellular Bax- and Apaf-1-positive cells were increased dose-dependently. Beneficially, FN-treated tumor-bearing mice exhibited reduced tumor mass and intercellular miR-375 expression. Meanwhile, immuno-labeled cells and proteins of Bax, Caspase-3, and Apaf-1 in FN-treated mice were increased dose-dependently, whereas ER alpha, p-PI3KCA (Tyr317), and p-AKT (Ser473) positive cells and proteins were downregulated, respectively. Collectively, our current results elucidate that FN exerts effective therapeutic benefits against OGS, and the pharmacological mechanism may be related to promoting cell apoptosis by inactivating intracellular miR-375/ER alpha-PI3K/AKT cascaded pathway.