The Subcellular Localization of IncRNA FAM230B in Osteosarcoma and Its Interaction with Early miR-203

Previous studies have revealed the role of lncRNA FAM230B in promoting papillary thyroid cancer and gastric cancer. We predicted that FAM230B may interact with miR-203 and studied the crosstalk between FAM230B and miR-203 in osteosarcoma (OS). Paired OS and nontumor tissues donated by 60 patients with OS were subjected to RNA isolations and quantitative real-time PCR (RT-qPCR) to analyze the expression of both FAM230B and miR-203 (mature and premature levels). Subcellular location of FAM230B in OS cells was detected using subcellular fractionation assay. RNA pull-down assay was performed to investigate the direct interaction between FAM230B and miR-203. Overexpression assays followed by RT-qPCR were performed to analyze the role of FAM230B in miR-203 maturation. Cell proliferation was studied with 5-Bromo-2-deoxyUridine (BrdU) assay. FAM230B and premature miR-203 were upregulated in OS, whereas mature miR-203 was downregulated in OS cells. FAM230B was detected in the cytoplasm and directly interacted with premature miR-203. FAM230B overexpression in OS cells increased premature miR-203 level and decreased mature miR-203 level. FAM230B increased cell proliferation and suppressed the role of miR-203 in inhibiting cell proliferation. FAM230B in the cytoplasm may sponge premature miR-203, thereby inhibiting miR-203 maturation to increase OS cell proliferation.