Therefore, circ_ORC2 binds with miR-19a and enhances its expression, thereby inhibiting downstream PTEN expression and activating Akt pathway to promote osteosarcoma cell growth and invasion.
Taken together, overexpression of miR-19a-3p was observed in OS cell lines and that downregulation of miR-19a-3p enhanced the chemosensitivity of OS cells to Cisplatin, by elevating the expression of the tumor suppressor, PTEN.
Additionally, kaplan-Meier analysis showed that both overall and disease-free survivals of osteosarcoma patients with high miR-19a expression were shorter than those with low miR-19a expression (both P<0.001).
We showed that knockdown of miR-19a by its antisense oligonucleotide (anti-miR-19a) significantly decreased the population of cancer stem cells in osteosarcoma cell lines.
K7M2 murine OS cells were transfected with miR-19a and cultured with nontransfected K7M2 cells in low-serum, hyperglycemic medium for up to 72 hours to induce TnT formation. miRNA transfer via TnTs was detected by time-lapse microscopic imaging. miR-19a was also transported via TnTs connecting transfected K7M2 cells and nontransfected stromal MC3T3 murine osteoblast cells.