MicroRNA-708-5p affects proliferation and invasion of osteosarcoma cells by targeting URGCP

The Double Face of miR-708: A Pan-Cancer Player with Dissociative Identity Disorder

Over the last decades, accumulating evidence has shown tumor-dependent profiles of miR-708, being either up- or downregulated, and thus, acting as a "Janus" regulator of oncogenic pathways. Herein, its functional duality was assessed through a thorough review of the literature and further validation in silico using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. In the literature, miR-708 was found with an oncogenic role in eight tumor types, while a suppressor tumor role was described in seven cancers. This double profile was also found in TCGA and GEO databases, with some tumor types having a high expression of miR-708 and others with low expression compared with non-tumor counterparts. The investigation of validated targets using miRBase, miRTarBase, and miRecords platforms, identified a total of 572 genes that appeared enriched for PI3K-Akt signaling, followed by cell cycle control, p53, Apellin and Hippo signaling, endocrine resistance, focal adhesion, and cell senescence regulations, which are all recognized contributors of tumoral phenotypes. Among these targets, a set of 15 genes shared by at least two platforms was identified, most of which have important roles in cancer cells that influence either tumor suppression or progression. In a clinical scenario, miR-708 has shown to be a good diagnostic and prognosis marker. However, its multitarget nature and opposing roles in diverse human tumors, aligned with insufficient experimental data and the lack of proper delivery strategies, hamper its potential as a sequence-directed therapeutic.

Role and Involvement of TENM4 and miR-708 in Breast Cancer Development and Therapy

Teneurin 4 (TENM4) is a transmembrane protein that is codified by the ODZ4 gene and is involved in nervous system development, neurite outgrowth, and neuronal differentiation. In line with its involvement in the nervous system, TENM4 has also been implicated in several mental disorders such as bipolar disorder, schizophrenia, and autism. TENM4 mutations and rearrangements have recently been identified in a number of tumors. This, combined with impaired expression in tumors, suggests that it may potentially be involved in tumorigenesis. Most of the TENM4 mutations that are observed in tumors occur in breast cancer, in which TENM4 plays a role in cells’ migration and stemness. However, the functional role that TENM4 plays in breast cancer still needs to be better evaluated, and further studies are required to better understand the involvement of TENM4 in breast cancer progression. Herein, we review the currently available data for TENM4′s role in breast cancer and propose its use as both a novel target with which to ameliorate patient prognosis and as a potential biomarker. Moreover, we also report data on the tumorigenic role of miR-708 deregulation and the possible use of this miRNA as a novel therapeutic molecule, as miR-708 is spliced out from TENM4 mRNA.

Anlotinib inhibits the proliferation, migration and invasion, and induces apoptosis of breast cancer cells by downregulating TFAP2C

The vascular endothelial growth factor receptor (VEGFR) network contributes to breast cancer pathogenesis and progression. Anlotinib is a highly potent multi-target tyrosine kinase inhibitor that has been previously shown to exert antitumor effects in various types of cancer. The aim of the present study is to investigate the effect of Anlotinib against breast cancer cells in vitro and uncover the possible underlying mechanisms. The human breast cancer cell line MCF-7 was treated with different concentrations of Anlotinib, before cell proliferation, migration, invasion and apoptosis were assessed using colony formation, wound healing, Transwell and TUNEL staining assays. In addition, the expression of transcription factor AP-2γ (TFAP2C) following Anlotinib stimulation was measured using reverse transcription-quantitative PCR and western blot analysis. TFAP2C was overexpressed in MCF-7 using transfection with a pcDNA3.1 vector, before the aforementioned experiments were repeated. The results revealed that Anlotinib impaired cell viability and colony formation, reduced proliferating cell nuclear antigen, Ki-67, MMP2, MMP9 and Bcl-2 expression levels, and inhibited cell migration and invasion. By contrast, the expression levels of tissue inhibitor of metalloproteinase 1, the frequency of apoptotic cells, the expression of Bax and the cleaved caspase-3/caspase-3 ratio increased in a concentration-dependent manner. Additionally, the expression of TFAP2C decreased after Anlotinib treatment. However, TFAP2C overexpression partially blocked the effects of Anlotinib on the proliferation, migration, invasion and apoptosis of MCF-7 cells. To conclude, Anlotinib suppressed proliferation, migration and invasion, whilst inducing apoptosis of MCF-7 cells, which may be partially dependent on the inhibition of TFAP2C expression.

LINC00665 Facilitates the Malignant Processes of Osteosarcoma by Increasing the RAP1B Expression via Sponging miR-708 and miR-142-5p

Osteosarcoma (OS) is a kind of fatal primary bone tumors in adolescents and young adults. Long noncoding RNAs (lncRNAs) are a group of noncoding RNAs which occupy a part of the latest hot topics. We aimed to investigate the roles of lncRNA LINC00665 in OS in this study. In this study, we found that LINC00665 was highly expressed in OS tissues and cell lines, and its high expression was associated with malignant feature and poor prognosis of OS. In OS cells, LINC00665 could facilitate the proliferation, migration, and invasion to play an oncogenic role. Mechanistically, LINC00665 served as a sponge for miR-708 and miR-142-5p and positively mediated the expression of their target RAP1B. Finally, we confirmed that LINC00665 exercised its biological functions by mediating RAP1B. In conclusion, LINC00665 is overexpressed in OS and facilitates the malignant processes of OS cells by increasing the RAP1B expression via sponging miR-708 and miR-142-5p.

Schisandrin B Inhibits Cell Viability and Migration, and Induces Cell Apoptosis by circ_0009112/miR-708-5p Axis Through PI3K/AKT Pathway in Osteosarcoma

Osteosarcoma is a primary tumor of bone and its incidence is increasing. Schisandrin B (Sch B), a generally used lignan in Chinese medicine, has been found to repress cancer progression. This study aims to reveal the effects and regulatory mechanism of Sch B in the viability, apoptosis and migration of osteosarcoma cells. In this study, we found circ_0009112 expression was higher and miR-708-5p expression was lower in SaOS2 and U2OS cells than in hFOB1.19 cells. Circ_0009112 expression was downregulated, but miR-708-5p was upregulated by Sch B treatment in a dose-dependent manner in SaOS2 and U2OS cells. Sch B exposure inhibited osteosarcoma development in vitro and in vivo; however, these effects were restored by circ_0009112. Furthermore, circ_0009112 acted as a sponge of miR-708-5p. Circ_0009112 regulated PI3K/AKT pathway after Sch B treatment by associating with miR-708-5p. Sch B exposure inhibited cell viability and migration, whereas promoted cell apoptosis by regulating circ_0009112/miR-708-5p axis through PI3K/AKT pathway in osteosarcoma cells. This study provided a theoretical basis for further studying osteosarcoma therapy with Sch B.

MiR-708 inhibits MC3T3-E1 cells against H2O2-induced apoptosis through targeting PTEN

Background

The dysregulation of proliferation and apoptosis plays a significant role in the pathogenesis of postmenopausal osteoporosis (PO). MicroRNAs play an important role in regulating apoptosis of MC3T3-E1 cells. However, the role and potential mechanism of miR-708 for regulating H₂O₂-induced apoptosis is unknown. This study aimed to investigate the protective function of miR-708 in H₂O₂-induced apoptosis of MC3T3-E1 osteoblasts.

Methods

MC3T3-E1 was co-cultured with H₂O₂ for 8 h, then, flow cytometry, malondialdehyde (MDA), and glutathione peroxidase (Gpx) levels were measured to establish the oxidative model. MiRNA microarray was performed to assess differentially expressed miRNAs between control and H₂O₂-treated MC3T3-E1 cells. We then performed RT-PCR to identify the relative expression of miR-708 and PTEN. After transfected MC3T3-E1 with miR-708 mimics, flow cytometry, MDA, and Gpx level were performed to identify the apoptosis rate and oxidative stress in these groups. Furthermore, we small interfering RNA of PTEN to identify the role of PTEN in H₂O₂-induced apoptosis of MC3T3-E1 cells.

Results

H₂O₂ (100 nM) could significantly induce the apoptosis of MC3T3-E1 cells. Moreover, H₂O₂ could significantly increase the MDA level and downregulated Gpx level. RT-PCR found that H₂O₂ significantly decrease the level of miR-708. Compared with H₂O₂ group, H₂O₂ + miR-708 mimic significantly decreased the apoptosis rate.

Conclusions

miR-708 plays a protective role in H₂O₂-induced MC3T3-E1 osteoblasts apoptosis and its protective effect is proceeded by regulating ROS level and PTEN expression level.

URG4 mediates cell proliferation and cell cycle in osteosarcoma via GSK3β/β-catenin/cyclin D1 signaling pathway

BACKGROUND

Osteosarcoma is one of the most common malignant bone tumors with the annual global incidence of approximately four per million. Upregulated gene 4 (URG4) expression in the osteosarcoma tissue is closely associated with recurrence, metastasis, and poor prognosis of osteosarcoma. However, the biological function and underlying mechanisms of URG4 in osteosarcoma have not been elucidated. This study aimed to explore the expression and underlying mechanism of URG4 in osteosarcoma.

METHODS

The expression level of URG4 in osteosarcoma and normal tissues was compared using immunohistochemistry (IHC). PCR and western blotting (WB) techniques are used to detect URG4 mRNA and protein levels. Wound healing and Transwell analysis to assess the effect of URG4 on osteosarcoma cell migration and invasion. Cell Counting Kit-8 assay and colony proliferation assay were performed to evaluate the effects of silencing URG4 on the inhibition of cell proliferation. The cell cycle distribution was detected by flow cytometry, and a xenograft mouse model was used to verify the function of URG4 in vivo.

RESULTS

URG4 was found to be highly expressed in osteosarcoma tissues and cells, and its high expression was correlated with advanced Enneking stage, large tumor size, and tumor metastasis in osteosarcoma patients. The proliferation in osteosarcoma cell lines and cell cycle in the S phase was suppressed when siRNA was used to downregulate URG4. URG4 promoted cell proliferation and tumorigenesis in vitro and in vivo. WB verified that URG4 promotes cell proliferation in osteosarcoma via pGSK3β/β-catenin/cyclinD1 signaling.

CONCLUSION

URG4, which is high-expressed in osteosarcoma, promotes cell cycle progression via GSK3β/β-catenin/cyclin D1 signaling pathway and may be a novel biomarker and potential target for the treatment of osteosarcoma.

SP1-Induced Upregulation of lncRNA LINC00514 Promotes Tumor Proliferation and Metastasis in Osteosarcoma by Regulating miR-708

Background

Growing studies have suggested the dysregulation of long non-coding RNAs (lncRNAs) in several tumors, including osteosarcoma (OS). However, limited studies report metastasis-associated lncRNAs in OS. Our present study aimed to explore the roles of lncRNA LINC00514 (LINC00514) in OS.

Materials and Methods

The LINC00514 expression was measured using qPCR assays in OS tissues and cell lines. The clinical significance of LINC00514 expression in OS patients was analyzed using chi-square test, Kaplan–Meier assays and multivariate analysis. The possible effects of LINC00514 in tumor cellular progression were determined using a series of functional assays. The mechanisms of LINC00514 action were explored through bioinformatics, luciferase reporter assays and RT-PCR assays. The mechanisms involved the upregulation of LINC00514 expression in OS were determined using luciferase reporter and chromatin immunoprecipitation (ChIP) assays.

Results

We showed that LINC00514 expressions were distinctly upregulated in both OS tissues and cell lines, especially in advanced cases. High levels of LINC0051 were positively correlated with advanced tumor stages, distant metastasis, and reduced survival of patients with OS. Functional experiments indicated that silencing of LINC00514 suppressed the ability of cell growth, colony formation and metastasis, whereas promoted cell apoptosis in vitro. Mechanistic investigation revealed that LINC00514 could directly bind to miR-708 and effectively serve as a ceRNA for miR-708. In addition, LINC00514 was upregulated by the transcription factor SP1.

Conclusion

Our findings revealed SP1-induced upregulation of LINC00514 as an oncogene in OS through competitively binding to miR-708, suggesting that there are potential diagnostic and treatment values of LINC00514 in OS.

LINC00514 drives osteosarcoma progression through sponging microRNA-708 and consequently increases URGCP expression

Long intergenic nonprotein-coding RNA 00514 (LINC00514) is upregulated in papillary thyroid cancer and contributes to its aggressiveness. In this study, we thoroughly explored the expression profile, specific functions, and relevant molecular mechanism of LINC00514 in osteosarcoma (OS). Herein, LINC00514 was significantly upregulated in OS tissues and cells, and increased LINC00514 expression was closely correlated with tumor size, TNM stage, and distant metastasis. OS patients with high LINC00514 expression had shorter overall survival than those with low LINC00514 expression. LINC00514 interference inhibited OS cell proliferation, colony formation, migration, and invasion in vitro but promoted cell apoptosis and G0/G1 cell cycle arrest. LINC00514 downregulation hindered OS tumor growth in vivo. Mechanistically, LINC00514 functioned as a competing endogenous RNA by directly interacting with microRNA-708-5p (miR-708) and consequently increasing the expression of upregulator of cell proliferation (URGCP). Both miR-708 knockdown and URGCP restoration partially neutralized anticancer activities of LINC00514 silencing in OS cells. LINC00514 increases URGCP expression by acting as a competing endogenous RNA for miR-708, thus exerting oncogenic roles in OS progression. In conclusion, the LINC00514/miR-708/URGCP pathway may be a promising target for drug discovery in the future.

The microRNA‑708‑5p/ZEB1/EMT axis mediates the metastatic potential of osteosarcoma

MicroRNA‑708‑5p (miR‑708‑5p) and epithelial‑​to‑mesenchymal transition (EMT) have been widely identified to contribute to the pathogenesis and progression of multiple cancers. However, the connection between miR‑708‑5p and EMT has not been sufficiently clarified. Therefore, our research aimed to investigate the impact of miR‑708‑5p on EMT and the metastasis of osteosarcoma (OS). We first analyzed the differentially expressed microRNAs (DEmiRNAs) from the GSE70367 dataset. We found that the expression of miR‑708‑5p was lower in OS cells. Overexpression of miR‑708‑5p was able to impair the migration and invasion of OS cells. Moreover, miR‑708‑5p inhibited EMT of OS cells MG63 and SaOS‑2, wherein E‑cadherin was increased, and N‑cadherin, vimentin, and Snail were decreased. Semaphorin 4C (SEMA4C), mitogen‑activated protein kinase kinase kinase 3 (MAP3K3), and zinc finger E‑box‑binding homeobox 1 (ZEB1) were predicted as target genes of miR‑708‑5p by bioinformatics method. Only ZEB1, one of the EMT‑inducing transcription factors, was validated as the direct target gene of miR‑708‑5p in OS cells through dual‑luciferase reporter assay and Western blot analysis. Knockdown of ZEB1 was found to inhibit the metastasis of MG63 and SaOS‑2 cells, whereas ZEB1 over-expression promoted their metastasis. In summary, miR‑708‑5p impaired the metastasis and EMT of OS, which was found to be mediated by inhibition of ZEB1.