miR-505 inhibits proliferation of osteosarcoma via HMGB1.

Osteosarcoma is a malignant bone tumor, and clinically detectable metastases can be detected in ~ 15-20% of patients when they seek medical advice; patients with metastatic disease have extremely poor prognosis. Here, we examined the involvement of the microRNA miR-505 in osteosarcoma. Eighty-four patients seeking treatment for osteosarcoma were included in the study group (SG), and 63 healthy subjects were allocated to the control group (CG). Normal human bone cells MG-63 and U20S cells were transfected with miR-505 mimics, miR-NC, HMGB1 RNA for targeted inhibition (si-HMGB1), and si-NC to examine the effects on HMGB1 expression. Cell proliferation, invasion, and apoptosis were measured using CCK-8, scratch assays, and flow cytometry (FCM), respectively, and the relationship between miR-505 and HMGB1 was determined using the dual-luciferase reporter assay. In patient tissues and serum, miR-505 was expressed at a low level, and HMGB1 was expressed at a high level, with an area under curve of > 0.9. Furthermore, the expression of miR-505 and HMGB1 in tissues had a positive association with that in the serum, whereas the expression of miR-505 had a negative association with that of HMGB1 in tissues only. Overexpression of miR-505 and silencing of HMGB1 suppressed the proliferation, migration, and invasion of osteosarcoma cells and increased the rate of apoptosis, whereas the co-transfected miR-505 mimics + si-HMGB1 demonstrated a more significant inhibitory effect on the proliferation and invasion of osteosarcoma cells and a higher apoptosis rate. miR-505 may inhibit the proliferation and invasion and promote apoptosis of osteosarcoma cells by targeting and suppressing HMGB1.