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

Epimedium-Curculigo herb pair enhances bone repair with infected bone defects and regulates osteoblasts through LncRNA MALAT1/miR-34a-5p/SMAD2 axis

Infected bone defects (IBDs) are the common condition in the clinical practice of orthopaedics. Although surgery and anti-infective medicine are the firstly chosen treatments, in many cases, patients experience a prolonged bone union process after anti-infective treatment. Epimedium-Curculigo herb pair (ECP) has been proved to be effective for bone repair. However, the mechanisms of ECP in IBDs are insufficiency. In this study, Effect of ECP in IBDs was verified by micro-CT and histological examination. Qualitative and quantitative analysis of the main components in ECP containing medicated serum (ECP-CS) were performed. The network pharmacological approaches were then applied to predict potential pathways for ECP associated with bone repair. In addition, the mechanism of ECP regulating LncRNA MALAT1/miRNA-34a-5p/SMAD2 signalling axis was evaluated by molecular biology experiments. In vivo experiments indicated that ECP could significantly promote bone repair. The results of the chemical components analysis and the pathway identification revealed that TGF-β signalling pathway was related to ECP. The results of in vitro experiments indicated that ECP-CS could reverse the damage caused by LPS through inhibiting the expressions of LncRNA MALAT1 and SMAD2, and improving the expressions of miR-34a-5p, ALP, RUNX2 and Collagen type І in osteoblasts significantly. This research showed that ECP could regulate the TGF-β/SMADs signalling pathway to promote bone repair. Meanwhile, ECP could alleviate LPS-induced bone loss by modulating the signalling axis of LncRNA MALAT1/miRNA-34a-5p/ SMAD2 in IBDs.

LncRNA KCNQ1OT1/miR-496/HMGB1 Signaling Axis Promotes Invasion and Migration of Non-small Cell Lung Cancer Cells

Enhanced invasion and migration of non-small cell lung cancer (NSCLC) cells is the major cause of metastasis and poor prognosis in NSCLC. This study was conducted to investigate the role and mechanism of lncRNA KCNQ1OT1 in the proliferation, invasion, and migration of NSCLC cells. The expression of KCNQ1OT1 in NSCLC was analyzed in the StarBase database, and the target miRNA of KCNQ1OT1 as well as the target genes of the miRNA was predicted. Then, the mRNA expression levels of KCNQ1OT1, miR-496, and HMGB1 were detected in clinical tissue samples and cells by qRT-PCR assay. Besides, the protein levels of HMGB1 were detected by Western blot. MTT assay, transwell assay, and scratch assay were used to determine the proliferation, invasion, and migration ability of NSCLC cells, respectively. Correlation analysis was performed to assess the correlation between the expression of KCNQ1OT1, miR-496, and HMGB1 in clinical NSCLC samples. Dual-luciferase reporter gene assay was conducted to analyze the interaction between KCNQ1OT1 and miR-496 and between miR-496 and HMGB1. The database results showed that KCNQ1OT1 was highly expressed in NSCLC. Similarly, we found that the expression level of KCNQ1OT1 was significantly higher in NSCLC tissues and cells than that in the corresponding normal tissues and cells. The results of MTT assay, transwell assay, and scratch assay demonstrated that KCNQ1OT1 significantly enhanced the proliferation, invasion, and migration of NSCLC cells. Further mechanism exploration revealed that KCNQ1OT1 could sponge miR-496, and miR-496 directly targeted and regulated the expression of HMGB1. The expression of miR-496 and either KCNQ1OT1 or HMGB1 were negatively correlated in NSCLC, while the expression of KCNQ1OT1 and HMGB1 were positively correlated. Compared with normal paracancer tissues, miR-496 was much lower and HMGB1 was much higher expressed in NSCLC tissues. The results of cotransfection also further demonstrated that miR-496 inhibitor or sh-HMGB1 cotransfected with sh-KCNQ1OT1 could significantly decrease or increase the ability of sh-KCNQ1OT1 to inhibit the proliferation, invasion, and migration of H1299 cells, respectively. In conclusion, lncRNA KCNQ1OT1 promotes the invasion and migration of NSCLC cells through miR-496/HMGB1 signaling axis.

High expression of SRSF1 facilitates osteosarcoma progression and unveils its potential mechanisms

BACKGROUND

SRSF1, a member of Serine/Arginine-Rich Splicing Factors (SRSFs), has been observed to significantly influence cancer progression. However, the precise role of SRSF1 in osteosarcoma (OS) remains unclear. This study aims to investigate the functions of SRSF1 and its underlying mechanism in OS.

METHODS

SRSF1 expression level in OS was evaluated on the TCGA dataset, TAGET-OS database. qRT-PCR and Western blotting were employed to assess SRSF1 expression in human OS cell lines as well as the interfered ectopic expression states. The effect of SRSF1 on cell migration, invasion, proliferation, and apoptosis of OS cells were measured by transwell assay and flow cytometry. RNA sequence and bioinformatic analyses were conducted to elucidate the targeted genes, relevant biological pathways, and alternative splicing (AS) events regulated by SRSF1.

RESULTS

SRSF1 expression was consistently upregulated in both OS samples and OS cell lines. Diminishing SRSF1 resulted in reduced proliferation, migration, and invasion and increased apoptosis in OS cells while overexpressing SRSF1 led to enhanced growth, migration, invasion, and decreased apoptosis. Mechanistically, Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and Gene Set Enrichment Analysis (GSEA) revealed that the biological functions of SRSF1 were closely associated with the dysregulation of the protein targeting processes, location of the cytosolic ribosome, extracellular matrix (ECM), and proteinaceous extracellular matrix, along with the PI3K-AKT pathway, Wnt pathway, and HIPPO pathway. Transcriptome analysis identified AS events modulated by SRSF1, especially (Skipped Exon) SE events and (Mutually exclusive Exons) MXE events, revealing potential roles of targeted molecules in mRNA surveillance, RNA degradation, and RNA transport during OS development. qRT-PCR confirmed that SRSF1 knockdown resulted in the occurrence of alternative splicing of SRRM2, DMKN, and SCAT1 in OS.

CONCLUSIONS

Our results highlight the oncogenic role of high SRSF1 expression in promoting OS progression, and further explore the potential mechanisms of action. The significant involvement of SRSF1 in OS development suggests its potential utility as a therapeutic target in OS.

MALAT1-regulated gene expression profiling in lung cancer cell lines

BACKGROUND

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and has a poor prognosis. Identifying biomarkers based on molecular mechanisms is critical for early diagnosis, timely treatment, and improved prognosis of lung cancer. MALAT1 has been reported to have overexpressed and tumor-promoting functions in NSCLC. It has been proposed as a potential biomarker for the diagnosis and prognosis of cancer. Therefore, this study was conducted to profile the changes in gene expression according to the regulation of expression of MALAT1 in NSCLC cell lines and to investigate the correlation through bioinformatic analysis of differentially expressed genes (DEGs).

METHODS

MALAT1 expression levels were measured using RT-qPCR. The biological functions of MALAT1 in NSCLC were analyzed by cell counting, colony forming, wound-healing, and Transwell invasion assays. In addition, gene expression profiling in response to the knockdown of MALAT1 was analyzed by transcriptome sequencing, and differentially expressed genes regulated by MALAT1 were performed by GO and KEGG pathway enrichment analyses. Bioinformatic databases were used for gene expression analysis and overall survival analysis.

RESULTS

Comparative analysis versus MALAT1 expression in MRC5 cells (a normal lung cell line) and the three NSCLC cell lines showed that MALAT1 expression was significantly higher in the NSCLC cells. MALAT1 knockdown decreased cell survival, proliferation, migration, and invasion in all three NSCLC cell lines. RNA-seq analysis of DEGs in NSCLC cells showed 198 DEGs were upregulated and 266 DEGs downregulated by MALAT1 knockdown in all three NSCLC cell lines. Survival analysis on these common DEGs performed using the OncoLnc database resulted in the selection of five DEGs, phosphoglycerate mutase 1 (PGAM1), phosphoglycerate mutase 4 (PGAM4), nucleolar protein 6 (NOL6), nucleosome assembly protein 1 like 5 (NAP1L5), and sestrin1 (SESN1). The gene expression levels of these selected DEGs were proved to gene expression analysis using the TNMplot database.

CONCLUSION

MALAT1 might function as an oncogene that enhances NSCLC cell survival, proliferation, colony formation, and invasion. RNA-seq and bioinformatic analyses resulted in the selection of five DEGs, PGAM1, PGAM4, NOL6, NAP1L5, and SESN1, which were found to be closely related to patient survival and tumorigenesis. We believe that further investigation of these five DEGs will provide valuable information on the oncogenic role of MALAT1 in NSCLC.

miR-222-3p-containing macrophage-derived extracellular vesicles confer gemcitabine resistance via TSC1-mediated mTOR/AKT/PI3K pathway in pancreatic cancer

Gemcitabine resistance limits the efficacy of chemotherapy and maintains a challenge for treatment outcomes. Therefore, we aimed to clarify the downstream mechanisms underlying the role of miR-222-3p delivered by M2 macrophage-derived extracellular vesicles (M2 MDEs) in the chemoresistance of pancreatic cancer (PCa). We separated the mouse macrophages and polarized them to M2 phenotypes, from which the EVs were derived. miR-222-3p was highly expressed in M2 MDEs. M2 MDEs were internalized by PCa cells. miR-222-3p overexpressing M2 MDEs were treated with gemcitabine and co-cultured with PCa cells for in vitro experiments. Co-culture with M2 MDEs enriched with miR-222-3p suppressed the sensitivity to gemcitabine, accompanied by diminished apoptosis and promoted proliferation. Furthermore, the M2 MDEs and PCa cells were injected to mice with gemcitabine exposure for in vivo substantiation. The delivery of miR-222-3p inhibitor by M2 MDEs suppressed tumor growth and elevated sensitivity of cancer cells to gemcitabine. Moreover, miR-222-3p was indicated to target and suppress TSC1 expression, while miR-222-3p activated the PI3K/AKT/mTOR pathway. Together, miR-222-3p-containing M2 MDEs enhance chemoresistance in PCa through TSC1 inhibition and activation of the PI3K/AKT/mTOR pathway.

IncRNA MALAT1 Regulates the Proliferation, Apoptosis, Migration, and Invasion of Osteosarcoma Cells by Targeting miR-873-5p/ROCK1

The malignant bone tumor osteosarcoma (OS) was one of the most aggressive tumors. Despite breakthroughs in treatment options for OS recently, the survival rate of patients with metastasis or reoccurring disease has remained unchanged over the last 25 years, at around 20%. lncRNA expression dysregulation is linked to carcinogenesis, advancement, and metastasis. Additionally, the fundamental mechanism of lncRNAs in regulating OS cell biological activity and progression is still being investigated. The expression of miR-873-5p and MALAT1 were detected by quantitative real-time polymerase chain reaction (qRT-PCR) in OS. The relationship between the expression level of MALAT1 and the survival rate of OS individuals was evaluated by the Kaplan-Meier plotter. The tumor cell's capability of proliferation was determined using the CCK-8. Transwell was used to test the migratory and invasive properties of tumor cells. ROCK1 protein expression was analyzed by western blot, while qRT-PCR was used to detect ROCK1 mRNA expression. Targeted genes of MALAT1 or miR-873-5p were predicted by StarBase2.0. The target association among miR-873-5p and MALAT1 or ROCK1 was confirmed using the luciferase assay. The relationship between ROCK1 and MALAT1 or miR-873-5p expression in OS was investigated using Spearman's correlation analysis. MALAT1 was up-regulated and was linked to a lower survival rate of patients in OS. The malignant behaviors of cells were inhibited by down-regulated MALAT1 in vitro. Dual-luciferase gene experiments confirmed the presence of MALAT1/miR-873-5p/ROCK1 axis. The up-regulated miR-873-5p blocked the promoted effects of MALAT1 on cell behaviors. Over-expressed MALAT1 promoted the malignant behaviors of cells by miR-873-5p/ROCK1 axis in OS.

LncRNAs could play a vital role in osteosarcoma treatment: Inhibiting osteosarcoma progression and improving chemotherapy resistance

Osteosarcoma (OS) is one of the most common primary solid malignant tumors in orthopedics, and its main clinical treatments are surgery and chemotherapy. However, a wide surgical resection range, functional reconstruction of postoperative limbs, and chemotherapy resistance remain as challenges for patients and orthopedists. To address these problems, the discovery of new effective conservative treatments is important. Long non-coding RNAs (lncRNAs) are RNAs longer than 200 nucleotides in length that do not encode proteins. Researchers have recently found that long non-coding RNAs are closely associated with the development of OS, indicating their potentially vital role in new treatment methods for OS. This review presents new findings regarding the association of lncRNAs with OS and summarizes potential clinical applications of OS with lncRNAs, including the downregulation of oncogenic lncRNAs, upregulation of tumor suppressive lncRNAs, and lncRNAs-based treatment to improve chemotherapy resistance. We hope these potential methods will be translated into clinical applications and greatly reduce patient suffering.

Regulation of the Inflammatory Response, Proliferation, Migration, and Epithelial-Mesenchymal Transition of Human Lens Epithelial Cells by the lncRNA-MALAT1/miR-26a-5p/TET1 Signaling Axis

Background

The ocular inflammatory microenvironment has been reported to be closely associated with the occurrence and progression of highly myopic cataract (HMC). Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) could alter the biological properties of mammalian cells by modulating the expression of inflammatory mediators; therefore, it may contribute to the development of HMC.

Objective

To investigate the function of MALAT1 in the inflammatory response, proliferation, migration, and epithelial-mesenchymal transition (EMT) of inflammatory and injured human lens epithelial cells (HLECs) and to reveal the underlying molecular signals.

Methods

Patients with HMC and age-related cataract (ARC) with an axial length of more than 26 mm were selected, and the anterior capsular tissue was obtained during cataract surgery. TNF-α (20 ng/mL) was chosen to induce inflammatory damage in HLECs to simulate the inflammatory microenvironment in HMC eyes. Specific siRNAs, inhibitors, and mimics were used to suppress or enhance the functions of MALAT1 and miR-26a-5p. RT-qPCR and Western blot analysis were performed to measure gene and protein expression, respectively.

Results

The expression of MALAT1 and the inflammatory mediators IL-6, MMP-2, and MMP-9 were significantly higher in HMC anterior capsule tissues than in ARC. TNF-α treatment increased the expression of MALAT1, while it also promoted the proliferation, migration, and EMT of HLECs. MALAT1 interference decreased the expression of IL-6 and MMP-2 and inhibited the aforementioned processes. Furthermore, MALAT1 negatively regulated the expression of miR-26a-5p and then promoted TET1 expression. TET1 was identified as a direct target of miR-26a-5p, and the promoting effect of MALAT1 on TET1 expression could be reversed by miR-26a-5p mimics.

Conclusion

The inflammatory environment and MALAT1 expression could be reciprocally induced in HLECs. MALAT1 may act as a ceRNA via the "sponge" miR-26a-5p and target TET1 to regulate the inflammatory response, proliferation, migration, and EMT processes in HLECs.

ST8SIA6-AS1 contributes to hepatocellular carcinoma progression by targeting miR-142-3p/HMGA1 axis

Hepatocellular carcinoma (LIHC) accounts for 90% of all liver cancers and is a serious health concern worldwide. Long noncoding RNAs (lncRNAs) have been observed to sponge microRNAs (miRNAs) and participate in the biological processes of LIHC. This study aimed to evaluate the role of the ST8SIA6-AS1-miR-142-3p-HMGA1 axis in regulating LIHC progression. RT-qPCR and western blotting were performed to determine the levels of ST8SIA6-AS1, miR-142-3p, and HMGA1 in LIHC. The relationship between ST8SIA6-AS1, miR-142-3p, and HMGA1 was assessed using luciferase assay. The role of the ST8SIA6-AS1-miR-142-3p-HMGA1 axis was evaluated in vitro using LIHC cells. Expression of ST8SIA6-AS1 and HMGA1 was significantly upregulated, whereas that of miR-142-3p was markedly lowered in LIHC specimens and cells. ST8SIA6-AS1 accelerated cell growth, invasion, and migration and suppressed apoptosis in LIHC. Notably, ST8SIA6-AS1 inhibited HMGA1 expression by sponging miR-142-3p in LIHC cells. In conclusion, sponging of miR-142-3p by ST8SIA6-AS1 accelerated the growth of cells while preventing cell apoptosis in LIHC cells, and the inhibitory effect of miR-142-3p was abrogated by elevating HMGA1 expression. The ST8SIA6-AS1-miR-142-3p-HMGA1 axis represents a potential target for the treatment of patients with LIHC.

LncRNA MALAT1-related signaling pathways in osteosarcoma

Osteosarcoma (OS) is a common and malignant form of bone cancer, which affects children and young adults. OS is identified by osteogenic differentiation and metastasis. However, the exact molecular mechanism of OS development and progression is still unclear. Recently, long non-coding RNAs (lncRNA) have been proven to regulate OS proliferation and drug resistance. LncRNAs are longer than 200 nucleotides that represent the extensive applications in the processing of pre-mRNA and the pathogenesis of human diseases. Metastasis-associated lung adenocarcinoma transcript-1 (MALAT1) is a well-known lncRNA known as a transcriptional and translational regulator. The aberrant expression of MALAT1 has been shown in several human cancers. The high level of MALAT1 is involved in OS cell growth and tumorigenicity by targeting several signaling pathways and miRNAs. Hence, MALAT1 might be a suitable approach for OS diagnosis and treatment. In this review, we will summarize the role of lncRNA MALAT1 in the pathophysiology of OS.

Modulation of immunosuppressive cells and noncoding RNAs as immunotherapy in osteosarcoma

The most common bone cancer is osteosarcoma (OS), which mostly affects children and teenagers. Early surgical resection combined with chemotherapy significantly improves the prognosis of patients with OS. Existing chemotherapies have poor efficacy in individuals with distant metastases or inoperable resection, and these patients may respond better to novel immunotherapies. Immune escape, which is mediated by immunosuppressive cells in the tumour microenvironment (TME), is a major cause of poor OS prognosis and a primary target of immunotherapy. Myeloid-derived suppressor cells, regulatory T cells, and tumour-associated macrophages are the main immunosuppressor cells, which can regulate tumorigenesis and growth on a variety of levels through the interaction in the TME. The proliferation, migration, invasion, and epithelial-mesenchymal transition of OS cells can all be impacted by the expression of non-coding RNAs (ncRNAs), which can also influence how immunosuppressive cells work and support immune suppression in TME. Interferon, checkpoint inhibitors, cancer vaccines, and engineered chimeric antigen receptor (CAR-T) T cells for OS have all been developed using information from studies on the metabolic properties of immunosuppressive cells in TME and ncRNAs in OS cells. This review summarizes the regulatory effect of ncRNAs on OS cells as well as the metabolic heterogeneity of immunosuppressive cells in the context of OS immunotherapies.

rAAV-based and intraprostatically delivered miR-34a therapeutics for efficient inhibition of prostate cancer progression

At present, there is no effective treatment for prostate cancer (PCa). Previous studies have reported that miR-34a is significantly downregulated in PCa cells; therefore, modulation of miR-34a expression might be a promising therapeutic approach for PCa treatment. To this end, we first verified the downregulation of miR-34a in prostate tumors from a transgenic adenocarcinoma mouse prostate (TRAMP) model. We found that miR-34a overexpression significantly inhibited the cell cycle, viability, and migration of PCa cells by targeting its downstream genes. Next, we tested the concept of intraprostatic injection of rAAV9·pri-miR-34a into 8-week-old TRAMP mice to inhibit PCa progression. We observed that the treatment lowered body weights significantly compared to the control treatment starting at 30 weeks after injection. rAAV9·pri-miR-34a treatment also obviously extended the lifespan of TRAMP mice. Moreover, we confirmed that the neoplasia in the treated prostates was significantly diminished compared to that in the control group. In addition, overexpressed miR-34a downregulated the expression of its target genes. Taken together, our results demonstrated, for the first time, the potential of rAAV-mediated efficient modulation of miR-34a expression in the prostate to inhibit PCa progression by regulating its downstream gene expression.

Long Non-coding RNA MALAT1 Is Depleted With Age in Skeletal Muscle in vivo and MALAT1 Silencing Increases Expression of TGF-β1 in vitro

Long non-coding RNAs (lncRNAs) are thought to function as “sponges” for microRNAs, but a role for such competing endogenous RNAs (ceRNAs) in muscle aging is not well understood. We therefore examined in skeletal muscles of young (4–6 months) and aged (22–24) male and female mice the expression of lncRNA MALAT1, which is predicted in silico to bind the senescence-associated microRNA miR-34a-5p. Results indicate a significant decrease in lncRNA MALAT1 expression in mouse skeletal muscle with age that coincides with an age-related increase in miR-34a-5p expression. In vitro studies using mouse C2C12 myoblasts demonstrate that MALAT1 silencing using siRNA increases miR-34a expression, consistent with a role for MALAT1 as an inhibitor of miR-34a-5p activity. Levels of reactive oxygen species (ROS) are known to increase in muscle with age, and so we treated C2C12 cells with hydrogen peroxide (10 and 100 μM) to examine changes in MALAT1 expression. MALAT1 expression decreased significantly with H2O2 treatment, but this effect was attenuated with p53 siRNA. Finally, miR-34a-5p is implicated in tissue fibrosis, and so we assessed the expression of TGF-β1 after MALAT1 silencing. MALAT1 siRNA significantly increased the expression of TGF-β1 in C2C12 cells. These findings suggest that age-related fibrosis and muscle atrophy mediated by ROS may result at least in part from an increase in miR-34a bioavailability resulting from a decline in miR-34a “sponging” due to ceRNA MALAT1 depletion. Crosstalk between MALAT1 and miR-34a may therefore represent a therapeutic target for improving muscle function with aging.

Hyaluronic Acid-Modified Nanoparticles Self-Assembled from Linoleic Acid-Conjugated Chitosan for the Codelivery of miR34a and Doxorubicin in Resistant Breast Cancer

In this study, a chitosan-based, self-assembled nanosystem that codelivered microRNA34a (miR34a) and doxorubicin (Dox) with hyaluronic acid (HA) modification (named CCmDH NPs) was developed to reverse the resistance of breast cancer (BCa) cells to Dox. The CCmDH NPs had a diameter of 180 ± 8.3 nm and a ζ potential of 16.5 mV with a slow-release effect for 96 h. The codelivery system could protect miR34a from nuclease and serum degradation and transport miR34a and Dox into drug-resistant MCF-7/A cells. In addition, the CCmDH NPs could inhibit proliferation and promote apoptosis by regulating the protein expression of B-cell lymphoma-2 (Bcl-2) and poly(ADP-ribose) polymerase (PARP) and inhibit invasion, metastasis, and adhesion by regulating E-cadherin, N-cadherin, MMP2, CD44, and Snail molecules. The CCmDH NPs induced a 73.7% tumor reduction in xenograft tumor growth in nude mice in vivo. This study provides evidence for the anticancer activity of CCmDH NPs carrying Dox and miR34a in BCa, especially metastatic Dox-resistant BCa models.

Osteosarcoma and Metastasis

Osteosarcoma is the most common primary bone malignancy in adolescents. Its high propensity to metastasize is the leading cause for treatment failure and poor prognosis. Although the research of osteosarcoma has greatly expanded in the past decades, the knowledge and new therapy strategies targeting metastatic progression remain sparse. The prognosis of patients with metastasis is still unsatisfactory. There is resonating urgency for a thorough and deeper understanding of molecular mechanisms underlying osteosarcoma to develop innovative therapies targeting metastasis. Toward the goal of elaborating the characteristics and biological behavior of metastatic osteosarcoma, it is essential to combine the diverse investigations that are performed at molecular, cellular, and animal levels from basic research to clinical translation spanning chemical, physical sciences, and biology. This review focuses on the metastatic process, regulatory networks involving key molecules and signaling pathways, the role of microenvironment, osteoclast, angiogenesis, metabolism, immunity, and noncoding RNAs in osteosarcoma metastasis. The aim of this review is to provide an overview of current research advances, with the hope to discovery druggable targets and promising therapy strategies for osteosarcoma metastasis and thus to overcome this clinical impasse.

MALAT-1 is Associated with the Doxorubicin Resistance in U-2OS Osteosarcoma Cells

Purpose

Our study aimed to investigate the relationship between MALAT-1 (metastasis-associated lung adenocarcinoma transcript 1) expression and the chemotherapy drug resistance in osteosarcoma.

Methods

The U-2OS osteosarcoma cell line was selected for the experiment. The cells were treated with methotrexate, doxorubicin, cisplatin, and ifosfamide, respectively. RT-PCR was applied to detect the MALAT-1 expression in cells. The doxorubicin-resistant cell line was constructed. The cells were divided into doxorubicin-sensitivity group (DS/shCtrl), doxorubicin-resistance group (DR/shCtrl) and shMALAT1-doxorubicin-resistance group (DR/shMALAT1). The colony formation assay and 5-ethynyl-2ʹ-deoxyuridine (EdU) assay were used to detect cell proliferation. PI staining was used to detect the cell cycle. Transwell assay and wound healing assay were used to observe the migration and invasion ability. Annexin V-FITC assay was used to detect cell apoptosis. Western blot was used to detect the protein expression and potential mechanism. The impacts of MALAT-1 expression were verified in vivo.

Results

The MALAT-1 was upregulated in the doxorubicin-resistant U-2OS osteosarcoma cells. Downregulating MALAT-1 in the doxorubicin-resistant cells inhibited the proliferation, migration, and invasiveness, increased the ratio of cells in the G0/G1 phase, promoted apoptosis. In the doxorubicin-resistant U-2OS cells, the extracellular regulated protein kinases (ERK) phosphorylation was declined, which could be reversed by downregulating MALAT-1. In vivo assay indicated that the growth of doxorubicin-resistant solid osteosarcoma could be suppressed by downregulating MALAT-1.

Conclusion

Our study provides evidence that doxorubicin may upregulate MALAT-1 in osteosarcoma. Downregulating MALAT-1 in the doxorubicin resistance U-2OS cells could reverse the resistance and may improve chemotherapeutic efficiency. Some conclusions in previous literature may be one-sided.

Circ_0081001 down-regulates miR-494-3p to enhance BACH1 expression and promotes osteosarcoma progression

The study was aimed at deciphering the function and mechanism of circ_0081001 in osteosarcoma (OS). In this study, quantitative real-time polymerase chain reaction (qRT-PCR) was utilized for quantifying circ_0081001, miR-494-3p, and BTB domain and CNC homolog 1 (BACH1) mRNA expressions in OS tissues and cells. Cell counting kit-8 (CCK-8) assay, together with 5-Ethynyl-2'-deoxyuridine (EdU) assay, was performed for evaluating cell proliferation; the alterations in apoptosis were analyzed utilizing flow cytometry; Transwell assay was conducted for examining cell migration and invasion; moreover, Western blot was utilized for the quantification of BACH1 protein expression; bioinformatics, dual-luciferase reporter gene, and RNA-binding protein immunoprecipitation assays were executed for validating the binding relationships between circ_0081001 and miR-494-3p, and between miR-494-3p and BACH1. As shown, circ_0081001, whose expression was elevated in OS tissues, had a negative association with miR-494-3p expression and a positive correlation with BACH1 expression. After circ_0081001 was overexpressed, the proliferation, migration, and invasion of OS cells were boosted but the apoptosis was reduced, whereas miR-494-3p exhibited opposite effects. The binding sites between circ_0081001 and miR-494-3p, and between miR-494-3p and the 3’UTR of BACH1 were experimentally verified. In conclusion, circ_0081001/miR-494-3p/BACH1 axis promoted the malignant biological behaviors of OS cells.

Long non-coding RNA FGD5-AS1 enhances osteosarcoma cell proliferation and migration by targeting miR-506-3p/RAB3D axis

Osteosarcoma (OSA), the malignant bone tumor, predominantly affecting children and adolescents, threatens the life and life quality of the patients. An increasing number of studies have indicated the role of long non-coding RNA (lncRNA) dysregulation in cancer biology. Herein, the study was aimed to explore the role of FGD5 antisense RNA 1 (FGD5-AS1), a lncRNA, in OSA. Expression levels of FGD5-AS1, miR-506-3p and RAB3D mRNA were quantified utilizing qRT-PCR. The expression of RAB3D protein was examined employing Western blot. A series of functional experiments including CCK-8 assay, BrdU assay, wound healing assay, Transwell assay were performed for studying the effects of FGD5-AS1 on the malignancy of OSA cell lines 143B and HOS. The binding site between miR-506-3p and FGD5-AS1 was identified and validated by luciferase reporter assay and RNA immunoprecipitation assay. It was demonstrated that the expression of FGD5-AS1 was up-regulated in OSA tissues and cell lines, and its high expression is associated with higher Enneking stage and poorer histological differentiation. Gain-of-function and loss-of-function studies suggested that FGD5-AS1 facilitated OSA cells proliferation and migration. The promoting effects of FGD5-AS1 overexpression on OSA cell proliferation and migration could be counteracted by miR-506-3p. Moreover, FGD5-AS1 competitively adsorbed miR-506-3p to repress its expression so as to up-regulate the expression of RAB3D. These results indicate that FGD5-AS1 is capable of expediting OSA cell proliferation and migration via sponging miR-506-3p to up-regulate RAB3D.

The Involvement of Long Non-Coding RNAs in Bone

A harmonious balance between osteoblast and osteoclast activity guarantees optimal bone formation and resorption, pathological conditions affecting the bone may arise. In recent years, emerging evidence has shown that epigenetic mechanisms play an important role during osteoblastogenesis and osteoclastogenesis processes, including long non-coding RNAs (lncRNAs). These molecules are a class of ncRNAs with lengths exceeding 200 nucleotides not translated into protein, that have attracted the attention of the scientific community as potential biomarkers to use for the future development of novel diagnostic and therapeutic approaches for several pathologies, including bone diseases. This review aims to provide an overview of the lncRNAs and their possible molecular mechanisms in the osteoblastogenesis and osteoclastogenesis processes. The deregulation of their expression profiles in common diseases associated with an altered bone turnover is also described. In perspective, lncRNAs could be considered potential innovative molecular biomarkers to help with earlier diagnosis of bone metabolism-related disorders and for the development of new therapeutic strategies.

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 RNAs in Gammaherpesvirus Infections: Their Roles in Tumorigenic Mechanisms

Long non-coding RNAs (lncRNAs) regulate gene expression at the epigenetic, transcriptional, or posttranscriptional level by interacting with protein, DNA, and RNA. Emerging evidence suggests that various lncRNAs are abnormally expressed and play indispensable roles in virus-triggered cancers. Besides, a growing number of studies have shown that virus-encoded lncRNAs participate in tumorigenesis. However, the functions of most lncRNAs in tumors caused by oncogenic viruses and their underlying mechanisms remain largely unknown. In this review, we summarize current findings regarding lncRNAs involved in cancers caused by Epstein–Barr virus (EBV) and Kaposi’s sarcoma herpesvirus (KSHV). Additionally, we discuss the contribution of lncRNAs to tumor occurrence, development, invasion, and metastasis; the roles of lncRNAs in key signaling pathways and their potential as biomarkers and therapeutic targets for tumor diagnostics and treatment.

Long Non-coding RNA LINC00115 Contributes to the Progression of Colorectal Cancer by Targeting miR-489-3p via the PI3K/AKT/mTOR Pathway

Long non-coding RNAs (lncRNAs) are tumor-related regulators and have been found to be involved in the underlying molecular mechanisms of colorectal cancer (CRC). However, the role of lncRNA LINC00115 during CRC progression is not entirely elucidated. In this study, we discovered that LINC00115 was significantly overexpressed in CRC, and its overexpression predicted poor patient outcomes. Downregulation of LINC00115 markedly inhibited CRC cell proliferation, increased cell apoptosis, and suppressed cell migration and invasion. Moreover, downregulation of LINC00115 led to the inactivation of PI3K/AKT/mTOR signaling. Bioinformatics analysis identified miR-489-3p as a candidate target of LINC00115. Furthermore, we revealed an inverse correlation between LINC00115 and miR-489-3p in CRC tissues. Importantly, by luciferase reporter assay, we found that miR-489-3p might directly target LINC00115, and downregulation of miR-489-3p could rescue the biological effects induced by the absence of LINC0015. In conclusion, our findings demonstrated that LINC00115 serves as an oncogene in CRC metastasis. Deeper understanding of the LINC00115/miR-489-3p axis might provide potential therapeutic targets against CRC metastasis.

LncRNA MALAT1 facilitates lung metastasis of osteosarcomas through miR-202 sponging

Lungs are the primary metastatic sites for osteosarcomas responsible for associated mortality. Recent data has documented role of long non-coding RNAs (lncRNAs) in proliferation and growth of osteosarcoma cells. We evaluated a role of lncRNAs in the lung metastasis of osteosarcoma with the goal of identifying a unique signature. Comparison of different lncRNAs in tumor samples from osteosarcoma with and without lung metastasis led to identification of MALAT1 as the most differentially upregulated lncRNA in the osteosarcoma patients with lung metastasis. MALAT1 was also high in osteosarcoma cells KRIB and MALAT1’s targeted downregulation in these cells led to decreased invasive potential and identification of miR-202 as the miRNA that is sponged by MALAT1. In the lung metastasis in vivo model, parental KRIB cells metastasized to lungs and such metastasis was significantly inhibited in KRIB cells with downregulated MALAT1. Ectopic miR-202 expression attenuated KRIB downregulation-mediated effects on lung metastasis. In yet another in vivo model involving parental SAOS-2 and lung-metastatic derivatives SAOS-2-LM, MALAT1 expression was found to be elevated in lung metastatic cells, which also correlated with reduced miR-202. In conclusion, MALAT1-miR-202 represents a potential lncRNA-miRNA signature that affects lung metastasis of osteosarcomas and could potentially be targeted for therapy.

Long Non-Coding RNA FEZF1-AS1 Modulates CXCR4 to Promote Cell Proliferation, Warburg Effect and Suppress Cell Apoptosis in Osteosarcoma by Sponging miR-144

BACKGROUND

Osteosarcoma (OS) is a common bone tumor among children, adolescents, and young adults. Long non-coding RNA (lncRNA) FEZF1 antisense RNA 1 (FEZF1-AS1) has been reported as an oncogene in diverse tumors including colorectal cancer, pancreatic cancer and hepatocellular carcinoma, as well as in osteosarcoma. This study focused on the functions and mechanism of lncRNA FEZF1-AS1 in osteosarcoma.

METHODS

The levels of FEZF1-AS1, microRNA miR-144 and CXC motif chemokine receptor 4 (CXCR4) in OS tissues and cells (Saos-2 and HOS) were measured by quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot assay. The interactions between miR-144 and FEZF1-AS1 or CXCR4 were predicted by DIANA tools online database. Then, the dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were conducted to validate the interactions. Moreover, the cell viability and apoptotic rate in transferred Saos-2 and HOS cells were assessed via 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometry, respectively. The levels of glucose and lactate productions were measured by glucose uptake and lactate production assay. In addition, the protein levels of Warburg-effect-related protein hexokinase 2 (HK2) and apoptosis-related proteins Bcl-2 or Bax in transferred Saos-2 and HOS cells were detected via Western blot assay.

RESULTS

The levels of FEZF1-AS1 and CXCR4 were strikingly up-regulated, and miR-144 was notably down-regulated in OS tissues and cells. DIANA tools online database exhibited that miR-144 was a direct target of FEZF1-AS1 and CXCR4 was a direct target of miR-144. Then the interactions were validated by dual-luciferase reporter assay and RIP assay. Functionally, FEZF1-AS1 silencing or miR-144 overexpression inhibited cell viability, the glucose and lactate productions and promoted cell apoptosis in Saos-2 and HOS cells. Furthermore, miR-144 inhibitor mitigated the inhibitory effects on cell viability, the glucose and lactate productions and the promoted effect on cell apoptosis rate in Saos-2 and HOS cells induced by FEZF1-AS1 depletion. Mechanistically, FEZF1-AS1 regulated CXCR4 in Saos-2 and HOS cells by sponging miR-144.

CONCLUSION

We verified that FEZF1-AS1, CXCR4 were up-regulated, and miR-144 was downregulated in OS tissues and cells. Furthermore, FEZF1-AS1 promoted cell proliferation, Warburg effect and suppressed cell apoptosis in osteosarcoma via miR-144/CXCR4 axis, this novel pathway may provide a basis for the further study of osteosarcoma.

Suppression of long noncoding RNA MALAT1 inhibits the development of uveal melanoma via microRNA-608-mediated inhibition of HOXC4

This study explored the effects of the metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) on the development of uveal melanoma. Moreover, the role of the MALAT1/microRNA-608 (miR-608)/homeobox C4 (HOXC4) axis was assessed by evaluating the proliferation, invasion, and migration, as well as the cell cycle distribution of uveal melanoma in vitro after knocking down MALAT1 or HOXC4 and/or overexpression of miR-608 in uveal melanoma cells (MUM-2B and C918). Moreover, the effects of the MALAT1/miR-608/HOXC4 axis in uveal melanoma in vivo were further evaluated by injecting the C918 cells into the NOD/SCID mice. HOXC4 was found to be a gene upregulated in uveal melanoma, while knockdown of its expression resulted in suppression of uveal melanoma cell migration, proliferation, and invasion, as well as cell cycle progression. In addition, the upregulation of miR-608 reduced the expression of HOXC4 in the uveal melanoma cells, which was rescued by overexpression of MALAT1. Hence, MALAT1 could upregulate the HOXC4 by binding to miR-608. The suppressed progression of uveal melanoma in vitro by miR-608 was rescued by overexpression of MALAT1. Additionally, in vivo assays demonstrated that downregulation of MALAT1 could suppress tumor growth through downregulation of HOXC4 expression via increasing miR-608 in uveal melanoma. In summary, MALAT1 downregulation functions to restrain the development of uveal melanoma via miR-608-mediated inhibition of HOXC4.

Growth hormone receptor promotes osteosarcoma cell growth and metastases

Osteosarcoma (OS) is the primary bone malignancy in children and adolescents, with a high incidence of lung metastasis and poor prognosis. Here, we report that growth hormone receptor (GHR) is overexpressed in OS samples compared with osteofibrous dysplasia. We subsequently demonstrated that GHR knockdown inhibited colony formation, promoted cell apoptosis and decreased the number of cells at G2/M phase in 143B and U2OS cells. Furthermore, knockdown of GHR inhibited tumor growth in vivo. Together, these findings indicate that GHR modulates cell proliferation and metastasis through the phosphoinositide 3‐kinase/AKT signaling pathway and may be suitable for use as a putative biomarker of OS.

Long noncoding RNA MALAT1 knockdown inhibits progression of anaplastic thyroid carcinoma by regulating miR-200a-3p/FOXA1

Long noncoding RNAs (lncRNAs) have been reported to play essential roles in progression of thyroid carcinoma. However, the roles of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in anaplastic thyroid carcinoma (ATC) process and its mechanism remain not been fully established. In this study, we focused on the effect of MALAT1 on cell proliferation, apoptosis, migration, invasion, and autophagy formation in ATC and explored the interaction between miR-200a-3p and MALAT1 or FOXA1. Moreover, murine xenograft model was established to investigate the roles and mechanism of MALAT1 in ATC progression in vivo. Results showed that MALAT1 expression was enhanced and miR-200a-3p was reduced in ATC tissues and cells. Knockdown of MALAT1 or overexpression of miR-200a-3p inhibited cell proliferation, migration and invasion but increased apoptosis and autophagy formation in ATC cells. Moreover, miR-200a-3p was directly bound to MALAT1 and its inhibition reversed the inhibitory effect of MALAT1 knockdown on progression of ATC. In addition, FOXA1 was indicated as a target of miR-200a-3p and its restoration attenuated the anti-cancer role of miR-200a-3p in ATC cells. Furthermore, MALAT1 functioned as a competing endogenous RNA (ceRNA) via sponging miR-200a-3p to derepress FOXA1 expression. Besides, interference of MALAT1 decreased tumor growth by upregulating miR-200a-3p and downregulating FOXA1. Collectively, MALAT1 knockdown suppressed ATC progression by regulating miR-200a-3p/FOXA1, providing a novel avenue for treatment of ATC.

Long noncoding RNA MALAT1 promotes the stemness of esophageal squamous cell carcinoma by enhancing YAP transcriptional activity

The tumor promoting roles of long noncoding RNA (lncRNA) MALAT1 have been revealed in various cancers; however, its roles in esophageal squamous cell carcinoma (ESCC) have not previously been disclosed. In this study, we found that MALAT1 expression was remarkably increased in ESCC cells compared to normal human esophageal epithelial cells. In addition, knockdown of MALAT1 attenuated the stemness of ESCC cells, as evidenced by a decrease in spheroid formation capacity, stemness marker expression and aldehyde dehydrogenase 1 activity. Moreover, MALAT1 knockdown decreased the migration ability of ESCC cells. Notably, knockdown of MALAT1 enhanced the radiosensitivity and chemosensitivity of ESCC cells. We also established that MALAT1 binds directly to Yes-associated protein (YAP), thereby enhancing YAP protein expression and increasing YAP transcriptional activity. Overexpression of YAP partially rescued the effect of MALAT1 knockdown on stemness and radiosensitivity of ESCC cells. Overall, this study has identified that a novel MALAT1-YAP axis promotes the stemness of ESCC cells, and thus could be a potential target for treatment of ESCC.

LncRNA MALAT1 increases the stemness of gastric cancer cells via enhancing SOX2 mRNA stability

Gastric cancer is one of the most common malignancies globally; cancer stem cells (CSCs) are regarded as being at the root of tumor progression, and there is thus a need to identify potential drugs to target CSCs. The long non-coding RNA MALAT1 promotes epithelial-mesenchymal transition and angiogenesis in colorectal cancer, but it is unknown whether it affects the stemness of gastric cancer cells. Here, we found that knockdown (KD) of MALAT1 attenuated the stemness of non-adherent gastric cancer cell spheroids, as evidenced by a decrease in primary and secondary spheroid formation capacity and expression of stemness markers. In contrast, overexpression (OE) of MALAT1 enhanced the stemness of adherent gastric cancer cells. Notably, KD of MALAT1 enhanced radiosensitivity and chemosensitivity of gastric cancer cell spheroids. We report that MALAT1 directly binds to sox2 mRNA (which encodes a critical master pluripotency factor), enhances the mRNA stability and increases its expression; KD of sox2 partially reversed the effect of MALAT1 OE on the stemness of gastric cancer cells. Importantly, expression of MALAT1 and sox2 exhibited a positive correlation in clinical samples. Therefore, our results indicate the existence of a novel MALAT1-sox2 axis which promotes the stemness of gastric cancer cells and may be a potential target for gastric cancer.

Long Noncoding RNA MALAT1 Acts as a Competing Endogenous RNA to Regulate TGF-β2 Induced Epithelial-Mesenchymal Transition of Lens Epithelial Cells by a MicroRNA-26a-Dependent Mechanism

The aim of the present study was to characterize whether the long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1)/miR-26a/Smad4 axis is involved in epithelial–mesenchymal transition (EMT) of lens epithelial cells (LECs). Primary human LECs were separated and cultured. Microarray analysis showed that a total of 568 lncRNAs are differentially expressed in primary HLECs in the presence of TGF-β2 and MALAT1 is mostly significantly dysregulated lncRNAs, which is increased by nearly 17-fold. In addition, upregulation of MALAT1 and downregulation of miR-26a were detected in human posterior capsule opacification (PCO) attached LECs and the LECs obtained from patients with anterior polar cataracts by quantitative RT-PCR (qRT-PCR). Next, our results showed that TGF-β2 induces overexpression of EMT markers in primary HLECs via a MALAT1-dependent mechanism. The mechanism is that MALAT1 negatively regulates miR-26a and miR-26a directly targets Smad4 by luciferase reporter assays and RNA-binding protein immunoprecipitation assay. In summary, TGF-β2 induces MALAT1 overexpression, which in turn MALAT1 acts as a ceRNA targeting Smad4 by binding miR-26a and promotes the progression of EMT of LECs.