miR-485-3p regulated by MALAT1 inhibits osteosarcoma glycolysis and metastasis by directly suppressing c-MET and AKT3/mTOR signalling.

Osteosarcoma (OS) is an extremely malignant bone cancer with high incidence and rapid progression. This study aims to investigate the role and underlying mechanisms of MALAT1 and miR-485-3p in OS. qRT-PCR and Western blotting were utilized to measure the levels of miR-485-3p, MALAT1, c-MET, AKT3, p-mTOR, mTOR, glycolysis-related proteins or migration-related proteins. Colony formation and transwell assay were used to test the roles of miR-485-3p, MALAT1, c-MET and AKT3 in cancer cell proliferation, migration and invasion. Dual luciferase assay was used to validate the interactions of miR-485-3p/c-MET, miR-485-3p/AKT3, and MALAT1/miR-485-3p. Glucose uptake assay and measurement of lactate production were employed to determine the glycolysis process. Mouse tumour xenograft model was used to determine the effect of shMALAT1 and miR-485-3p mimics on tumour growth and metastasis in vivo. miR-485-3p was decreased while c-MET, AKT3, and MALAT1 were increased in human OS tissues and cells. miR-485-3p bound directly to c-MET and AKT3 mRNAs and repressed OS cell glycolysis, proliferation, migration, and invasion through decreasing glycolysis-related proteins and migration-related proteins via inhibiting c-MET and AKT3/mTOR pathway. In addition, MALAT1 interacted with miR-485-3p and disinhibited c-MET and AKT3/mTOR signalling. Knockdown MALAT1 or overexpression of miR-485-3p restrained OS tumour growth and lung metastasis in vivo. miR-485-3p suppresses OS glycolysis, proliferation, and metastasis via inhibiting c-MET and AKT3/mTOR signalling and MALAT1 acts as a sponge of miR-485-3p. MALAT1 and miR-485-3p may be the key regulators in OS progression, and potential molecular targets for future OS therapy.

Wang Q ，Liu MJ ，Bu J ，Deng JL ，Jiang BY ，Jiang LD ，He XJ ... -  《-》

LncRNA MALAT1 Promotes Cancer Metastasis in Osteosarcoma via Activation of the PI3K-Akt Signaling Pathway.

LncRNAs have been reported to be vital regulators of the progression of osteosarcoma, although the underlying mechanisms are not completely understood. The levels of MALAT1 and miR-129-5p expression were measured using qRT-PCR. Cell growth was determined using the CCK-8 and colony formation assays. Cell migration and invasion were detected using the wound healing and Transwell invasion assays, respectively. Tumor growth was determined with a xenograft model. MALAT1 was significantly up-regulated in osteosarcoma tissues compared with adjacent non-tumor soft tissues. Overexpression of MALAT1 promoted osteosarcoma cell proliferation, migration, and invasion in vitro and enhanced tumor growth in a tumor xenograft mouse model. MALAT1 promoted osteosarcoma progression by modulating stem cell-like properties. Moreover, rescue experiment and luciferase reporter assay results indicated that MALAT1 modulates RET expression by sponging miR-129-5p in osteosarcomas. Furthermore, MALAT1 augmented the expression of downstream proteins of the RET-Akt pathway. MALAT1 was consistently significantly increased in osteosarcoma tissues and MALAT1 expression was positively correlated with tumor size and metastasis. High expression of MALAT1 was significantly associated with poor outcomes in patients with osteosarcomas. MALAT1 expression was positively related to RET and negatively related to miR-129-5p in osteosarcoma samples and xenograft tumors. MALAT1 functioned as an oncogenic lncRNA in osteosarcomas and was as an independent prognostic indicator. Our data revealed for the first time that MALAT1 increases stem cell-like properties by up-regulating RET via sponging miR-129-5p, and thus activates the PI3K-Akt signaling pathway and provides potential therapeutic targets for osteosarcoma treatment.

Chen Y ，Huang W ，Sun W ，Zheng B ，Wang C ，Luo Z ，Wang J ，Yan W ... -  《-》

Knockdown of MALAT1 inhibits osteosarcoma progression via regulating the miR‑34a/cyclin D1 axis.

Duan G ，Zhang C ，Xu C ，Xu C ，Zhang L ，Zhang Y ... -  《-》

circPVT1 promotes osteosarcoma glycolysis and metastasis by sponging miR-423-5p to activate Wnt5a/Ror2 signaling.

Osteosarcoma (OS) is the most prevalent form of bone cancer. It has a high metastatic potential and progresses rapidly. The molecular mechanisms of OS remain unclear and this study aims to examine the functional role of circPVT1 and miR-423-5p in OS. Quantitative RT-PCR (qRT-PCR) and western blotting were used to examine levels of miR-423-5p, circPVT1, Wnt5a, Ror2, and glycolysis-related proteins, including HK2, PKM2, GLUT1, and LDHA. Colony formation and transwell assays were used to test the roles of miR-423-5p, circPVT1, and Wnt5a/Ror2 in OS cell proliferation, migration, and invasion. Dual luciferase assay and Ago2-RIP were used to validate the interactions of miR-423-5p/Wnt5a, miR-423-5p/Ror2, and circPVT1/miR-423-5p. Glucose uptake assay and measurement of lactate production were performed to assess the glycolysis process. A nude mouse xenograft model was used to evaluate the effects of sh-circPVT1 and miR-423-5p mimics on tumor growth and metastasis in vivo. miR-423-5p was reduced in both OS tissues and OS cell lines, while Wnt5a/Ror2 and circPVT1 were elevated. miR-423-5p bound to 3'-UTR of Wnt5a and Ror2 mRNA, and inhibited glycolysis and OS cell proliferation, migration, and invasion by targeting Wnt5a and Ror2. circPVT1 interacted with miR-423-5p and activated Wnt5a/Ror2 signaling by sponging miR-423-5p. Knockdown of circPVT1 or overexpression of miR-423-5p suppressed OS tumor growth and metastasis in vivo. miR-423-5p inhibited OS glycolysis, proliferation, migration, and metastasis by targeting and suppressing Wnt5a/Ror2 signaling pathway, while circPVT1 promoted those processes by acting as a sponge of miR-423-5p.

Wan J ，Liu Y ，Long F ，Tian J ，Zhang C ... -  《-》

LINC01128 regulates the development of osteosarcoma by sponging miR-299-3p to mediate MMP2 expression and activating Wnt/β-catenin signalling pathway.

Osteosarcoma (OS) is one of the most common metastatic bone cancers, which results in significant morbidity and mortality. The important role of long non-coding RNAs (lncRNAs) in the biological processes of OS has been demonstrated through several studies. In the current study, we evaluated the role of the lncRNA, LINC01128, in OS. We analysed the expression of LINC01128 in three OS gene expression omnibus (GEO) data sets GSE21257, GSE36001 and GSE42352. The expression of LINC01128 in OS tissues and matched non-tumour tissues obtained from 50 OS patients was detected using qRT-PCR. The association between LINC01128 expression and overall survival of OS patients was evaluated using the Kaplan-Meier method. The effects of LINC01128 knockdown and overexpression were evaluated through in vitro and in vivo assays. The LINC01128/miR-299-3p/ MMP2 axis was verified using dual-luciferase reporter assay and qRT-PCR assays. GEO data sets analysis revealed that the expression of LINC01128 was increased in OS. Elevated LINC01128 expression was accompanied by shorter overall survival in OS patients. Functional studies revealed that LINC01128 knockdown reduced the proliferation, migration and invasion of OS cells both in vitro and in vivo. Mechanistically, LINC01128 sponged miR-299-3p to increase MMP2 expression. Rescue assays determined the role of the LINC01128/miR-299-3p/MMP2 axis in the proliferation, migration and invasion of OS cells. Additionally, the Wnt/β-catenin signalling pathway was activated by LINC01128 and MMP2 in OS cell lines. In summary, this study demonstrates that LINC01128 facilitates OS by functioning as a sponge of miR-299-3p, thus promoting MMP2 expression and activating the Wnt/β-catenin signalling pathway.

Yao Q ，Chen T 《-》