Long non-coding RNA ASBEL promotes osteosarcoma cell proliferation, migration, and invasion by regulating microRNA-21.

Osteosarcoma is the most common malignant bone tumor in children and adolescents with high rate of incidence, high frequency of recurrence, and high degree of metastasis. This study aimed to investigate the effects of long noncoding RNA antisense ncRNA in the abundant in neuroepithelium area (ANA)/B-cell translocation gene 3 (BTG3) locus (lncRNA ASBEL) on the pathogenesis of osteosarcoma. The expression levels of ASBEL in human osteoblast cells and human osteosarcoma cells were evaluated using qRT-PCR. Effects of ASBEL knockdown on cell viability, migration, and invasion were detected using trypan blue exclusion assay, cell migration, and cell invasion assay, respectively. The regulatory effects of ASBEL on microRNA-21 (miR-21) were analyzed using qRT-PCR. The roles of miR-21 and protein phosphatase 2A (PP2A), the possible downstream factor of miR-21, in osteosarcoma cell proliferation, migration, and invasion were also explored. The results showed that ASBEL was highly expressed in osteosarcoma cells. Knockdown of ASBEL inhibited osteosarcoma cell viability, migration, and invasion, as well as the expression level of miR-21. PP2A was a direct target of miR-21, which participated in the effects of ASBEL and miR-21 on the activation of phosphatidylinositol 3-kinase/protein kinase 3/glycogen synthase kinase-3β (PI3K/AKT/GSK3β) and mitogen-activated protein kinase/extracellular regulated protein kinase (MEK/ERK) signaling pathways as well as the enhancement of osteosarcoma cell proliferation, migration, and invasion. In conclusion, we verified that ASBEL-miR-21-PP2A pathway might play critical regulatory effects on the pathogenesis of osteosarcoma and could be as the potential therapeutic target and biomarker for osteosarcoma treatment.

Zhao J ，Zhang C ，Gao Z ，Wu H ，Gu R ，Jiang R ... -  《-》

Long Non-Coding RNA Urothelial Carcinoma Associated 1 Promotes Proliferation, Migration and Invasion of Osteosarcoma Cells by Regulating microRNA-182.

Previous studies demonstrated the oncogenic roles of lncRNA UCA1 in osteosarcoma. This study aimed to explore the internal molecular mechanism of UCA1 on promoting osteosarcoma cell proliferation, migration and invasion. qRT-PCR was conducted to measure the expression levels of UCA1, miR-182 and TIMP2. Cell transfection was used to change the expression levels of UCA1, miR-182 and TIMP2. Cell viability, migration, invasion and apoptosis were measured using CCK-8 assay, two-chamber migration (invasion) assay and Guava Nexin assay, respectively. The associations between UCA1, miR-182 and iASPP were analyzed by dual luciferase activity assay. The protein expression levels of key factors involved in cell apoptosis, PI3K/AKT/GSK3β pathway and NF-κB pathway, as well as p53, Rb, RECQ family and iASPP were evaluated by western blotting. UCA1 was highly expressed in osteosarcoma MG63 and OS-732 cells. Knockdown of UCA1 inhibited OS-732 cell viability, migration and invasion, but promoted cell apoptosis. miR-182 was up-regulated in OS-732 cells after UCA1 knockdown and participated in the effects of UCA1 on OS-732 cells. TIMP2 was downstream factor of miR-182 and involved in the regulatory roles of miR-182 on OS-732 cell viability, migration, invasion, apoptosis, as well as PI3K/AKT/GSK3β and NF-κB pathways. UCA1 knockdown up-regulated p53, Rb and RECQL5 levels in OS-732 cells, while down-regulated the expression of iASPP. TGF-β or TNF-α treatment could enhance the expression of UCA1 in OS-732 cells. Our research verified that UCA1 exerted oncogenic roles in osteosarcoma cells by regulating miR-182 and TIMP2, as well as PI3K/AKT/GSK3β and NF-κB pathways.

Li Q ，Xing W ，Gong X ，Wang Y ... -  《-》

LncRNA FER1L4 induces apoptosis and suppresses EMT and the activation of PI3K/AKT pathway in osteosarcoma cells via inhibiting miR-18a-5p to promote SOCS5.

Previous studies have determined that long non-coding RNA (lncRNA) Fer-1-like protein 4 (FER1L4) is suppressed in osteosarcoma (OS) and inhibits the tumorigenesis in a variety of cancer. However, the precise biological of FER1L4 in OS has not been cleared. The aim of this study is to investigate the roles and potential mechanisms of FER1L4 in apoptosis and epithelial-mesenchymal transition (EMT) in OS. In the present study, the levels of FER1L4 were decreased significantly in OS tissues and cell lines compared with non-tumorous tissues or hFOB1.19. Knockdown of FER1L4 in OS cells decreased the apoptosis rate, but increased the OS cell proliferation, upregulated the expression levels of CD133 and Nanog, as well as promoted Twist1 expression, increased the N-cadherin and Vimentin expression. In turn, the opposite trends were observed upon overexpression of FER1L4. In addition, the expression of PI3K, p-AKT (Ser470) and p-AKT (Thr308) was upregulated by siFER1L4, while decreased upon overexpression of FER1L4. MicroRNA (miRNA) -18a-5p, an osteosarcoma-promoting miRNA which was suggested a target of FER1L4 in osteosarcoma, was identified to be a functional target of FER1L4 on the regulating of cell apoptosis and EMT, presently. The effects of FER1L4 overexpression on the markers of cell apoptosis, proliferation, EMT, and stemness and PI3K/AKT signaling were all reversed by miR-18a-5p upregulation. Furthermore, the suppressor of cytokine signaling 5 (SOCS5) was confirmed a target gene of miR-18a-5p by luciferase gene reporter assay and SOCS5 suppression by miR-18a-5p attenuated the effects of FER1L4 overexpression on the OS cells apoptosis and the expressed levels of PI3K, AKT, Twist1, N-cadherin and Vimentin. In conclusion, our data indicated thatthe overexpression of FER1L4 promoted apoptosis and inhibited the EMT markers expression and PI3K/AKT signaling pathway activation in OS cells via downregulating miR-18a-5p to promote SOCS5.

Ye F ，Tian L ，Zhou Q ，Feng D ... -  《-》

Long Noncoding RNA GAS5 Suppresses Cell Growth and Epithelial-Mesenchymal Transition in Osteosarcoma by Regulating the miR-221/ARHI Pathway.

Dysregulated long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) play key roles in the development of human cancers. The lncRNA growth arrest-specific 5 (GAS5) is reported to be a tumor suppressor in multiple cancers. However, the roles of GAS5 and its related miRNAs in osteosarcoma are poorly understood. This study explored the potential functions and mechanisms of GAS5 in the tumorigenesis of osteosarcoma. Here, the expression of GAS5, miR-221 and aplasia Ras homologue member I (ARHI) was determined in osteosarcoma tissues and cells by Real-time PCR (RT-qPCR). The underlying mechanism of GAS5 in osteosarcoma growth was analyzed via MTT, Transwell, RT-qPCR, Western blot, dual-luciferase reporter assay, RNA immunoprecipitation, and xenograft models after GAS5 overexpression. GAS5 and ARHI levels were significantly reduced, while miR-221 increased, both in osteosarcoma tissues and cells. Overexpression of GAS5 suppressed the proliferation, migration, and epithelial-mesenchymal transition (EMT) of osteosarcoma cells. GAS5 could directly bind to miR-221 to decrease miR-221 expression and enhance ARHI expression. The effect of GAS5 overexpression on the proliferation, migration and EMT was reversed by miR-221 mimics or ARHI siRNA in osteosarcoma cells. Additionally, GAS5 suppressed tumor volume, Ki-67 and PCNA staining, and EMT process in the development of osteosarcoma in vivo. Taken together, lncRNA GAS5 functions as a competing endogenous RNA for miR-221 to suppress cell growth and EMT in osteosarcoma by regulating the miR-221/ARHI pathway. J. Cell. Biochem. 118: 4772-4781, 2017. © 2017 Wiley Periodicals, Inc.

Ye K ，Wang S ，Zhang H ，Han H ，Ma B ，Nan W ... -  《-》

Long non-coding RNA PVT1 promotes osteosarcoma development by acting as a molecular sponge to regulate miR-195.

Zhou Q ，Chen F ，Zhao J ，Li B ，Liang Y ，Pan W ，Zhang S ，Wang X ，Zheng D ... -  《Oncotarget》