Effect of lncRNA LET on proliferation and invasion of osteosarcoma cells

LncRNA CBR3-AS1 promotes osteosarcoma progression through the network of miR-140-5p/DDX54-NUCKS1-mTOR signaling pathway

Long noncoding RNA (lncRNA) CBR3-AS1 (termed as CBR3-AS1) has been reported to be upregulated in several cancers including osteosarcoma. Its positive impact on the proliferation, migration, and invasion of osteosarcoma cells has been unveiled; nevertheless, whether it also affects the stemness and epithelial-mesenchymal transition (EMT) of osteosarcoma cells is unclear. The purpose for this study was to explore the effects of CBR3-AS1 on the stemness and EMT of osteosarcoma cells as well as its underlying mechanism. qRT-PCR and western blot were applied to detect target gene expression. Function assays were conducted to evaluate the effect of genes on the stemness and EMT of osteosarcoma cells. Mechanism assays were done to verify the association among different genes. In vivo assays were also performed. The obtained data showed that CBR3-AS1 demonstrated a high expression in osteosarcoma cells. CBR3-AS1 could promote stemness and EMT of osteosarcoma cells as well as osteosarcoma tumor growth. Mechanically, CBR3-AS1 sponged miR-140-5p and recruited DDX54 to upregulate NUCKS1, thus activating the mTOR signaling pathway. Furthermore, NUCKS1 could facilitate stemness and EMT of osteosarcoma cells. In summary, this study reveals that CBR3-AS1 exerts an oncogenic role in osteosarcoma through modulating the network of the miR-140-5p/DDX54-NUCKS1-mTOR signaling pathway.

Bone Marrow Mesenchymal Stem Cells-Derived Extracellular Vesicles Promote Proliferation, Invasion and Migration of Osteosarcoma Cells via the lncRNA MALAT1/miR-143/NRSN2/Wnt/β-Catenin Axis

Introduction

Osteosarcoma is a malignant primary bone tumor. Bone marrow-derived mesenchymal stem cells-derived extracellular vesicles (BMSC-EVs) bear repair function for bone and cartilage. This study investigated the mechanism of BMSC-EVs in osteosarcoma cell proliferation, migration and invasion.

Methods

BMSC-EVs were isolated and identified. The effects of different concentrations of EVs on osteosarcoma cell proliferation, migration and invasion were evaluated. LncRNA MALAT1 expression in osteosarcoma cells was detected. BMSCs were transfected with si-MALAT1 or si-NC. The binding relationships between MALAT1 and miR-143, and miR-143 and NRSN2 were verified. Levels of NRSN2 and Wnt/β-catenin pathway key proteins were detected. miR-143 mimic was transfected into EVs-treated osteosarcoma cells. Nude mice were injected with MG63 cells to verify the effect of EVs on osteosarcoma growth in vivo.

Results

BMSC-EVs facilitated proliferation, invasion and migration of osteosarcoma cells. BMSC-EVs carried MALAT1 into osteosarcoma cells. BMSC-EVs-treated osteosarcoma cells showed increased MALAT1 and NRSN2 expressions, decreased miR-143 expression, and activated Wnt/β-catenin pathway. miR-143 mimic or si-MALAT1 reversed the effects of BMSC-EVs on osteosarcoma cells. In vivo experiment confirmed that BMSC-EVs promoted tumor growth in nude mice.

Discussion

BMSC-EVs promoted proliferation, invasion and migration of osteosarcoma cells via the MALAT1/miR-143/NRSN2/Wnt/β-catenin axis. This study might offer new insights into osteosarcoma management.

Long non‑coding RNA PCAT6 promotes the development of osteosarcoma by increasing MDM2 expression

Osteosarcoma is a severe malignant tumor. Several studies indicated that lncRNA prostate cancer-associated transcript 6 (PCAT6) promoted the development of multiple types of cancers. Studies have also revealed that MDM2 could aggravate tumor symptoms inhibiting P53 expression. However, whether lncRNA PCAT6 could affect the proliferation and metastasis of osteosarcoma cells by regulating P53 expression is unclear. The present study established lncRNA PCAT6-overexpressing osteosarcoma cells. Cell Counting Kit-8, wound healing and Transwell assays were performed to detect the change in proliferation, migration and invasion of these cells, respectively. Subsequently, E3 ubiquitin-protein ligase Mdm2 (MDM2), P53 and P21 expression were determined using western blotting. Finally, MDM2 expression was inhibited and the proliferation, migration and invasion of these cells was determined again. The present study found that the proliferation, migration and invasion of osteosarcoma cells increased following overexpression of lncRNA PCAT6. MDM2 expression was upregulated while the levels of P53 and P21 decreased following overexpression of lncRNA PCAT6. However, the proliferation, migration and invasion of osteosarcoma cells were inhibited following MDM2 knockdown. Additionally, P53 and P21 was rescued following MDM2 knockdown. To conclude, lncRNA PCAT6 promoted the proliferation, migration and invasion of osteosarcoma cells by promoting the expression of MDM2 and suppressing the expression of P53 and P21.