LncRNA ODRUL Contributes to Osteosarcoma Progression through the miR-3182/MMP2 Axis

Exploring the roles of non-coding RNAs in liver regeneration

Liver regeneration (LR) is a complex process encompassing three distinct phases: priming, proliferation phase and restoration, all influenced by various regulatory factors. After liver damage or partial resection, the liver tissue demonstrates remarkable restorative capacity, driven by cellular proliferation and repair mechanisms. The essential roles of non-coding RNAs (ncRNAs), predominantly microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNA (circRNA), in regulating LR have been vastly studied. Additionally, the impact of ncRNAs on LR and their abnormal expression profiles during this process have been extensively documented. Mechanistic investigations have revealed that ncRNAs interact with genes involved in proliferation to regulate hepatocyte proliferation, apoptosis and differentiation, along with liver progenitor cell proliferation and migration. Given the significant role of ncRNAs in LR, an in-depth exploration of their involvement in the liver's self-repair capacity can reveal promising therapeutic strategies for LR and liver-related diseases. Moreover, understanding the unique regenerative potential of the adult liver and the mechanisms and regulatory factors of ncRNAs in LR are crucial for improving current treatment strategies and exploring new therapeutic approaches for various liver-related diseases. This review provides a brief overview of the LR process and the ncRNA expression profiles during this process. Furthermore, we also elaborate on the specific molecular mechanisms through which multiple key ncRNAs regulate the LR process. Finally, based on the expression characteristics of ncRNAs and their interactions with proliferation-associated genes, we explore their potential clinical application, such as developing predictive indicators reflecting liver regenerative activity and manipulating LR processes for therapeutic purposes.

Osteosarcoma in a ceRNET perspective

Osteosarcoma (OS) is the most prevalent and fatal type of bone tumor. It is characterized by great heterogeneity of genomic aberrations, mutated genes, and cell types contribution, making therapy and patients management particularly challenging. A unifying picture of molecular mechanisms underlying the disease could help to transform those challenges into opportunities.This review deeply explores the occurrence in OS of large-scale RNA regulatory networks, denominated "competing endogenous RNA network" (ceRNET), wherein different RNA biotypes, such as long non-coding RNAs, circular RNAs and mRNAs can functionally interact each other by competitively binding to shared microRNAs. Here, we discuss how the unbalancing of any network component can derail the entire circuit, driving OS onset and progression by impacting on cell proliferation, migration, invasion, tumor growth and metastasis, and even chemotherapeutic resistance, as distilled from many studies. Intriguingly, the aberrant expression of the networks components in OS cells can be triggered also by the surroundings, through cytokines and vesicles, with their bioactive cargo of proteins and non-coding RNAs, highlighting the relevance of tumor microenvironment. A comprehensive picture of RNA regulatory networks underlying OS could pave the way for the development of innovative RNA-targeted and RNA-based therapies and new diagnostic tools, also in the perspective of precision oncology.

Tumor-derived exosomal linc00881 induces lung fibroblast activation and promotes osteosarcoma lung migration

Osteosarcoma (OS) commonly metastasizes to the lung, yet the underlying molecular mechanisms remain poorly understood. Exosomes play a crucial role in tumor migration, including OS lung migration. However, the underlying mechanism by which exosome-derived long non-coding RNAs (lncRNAs) contribute to lung migration in osteosarcoma (OS) remains unclear. This study presents a newly discovered lncRNA, linc00881, derived from OS exosomes. Our study shows that linc00881 promotes the migration of OS cells to the lung and induces the conversion of normal lung fibroblasts into cancer-associated fibroblasts (CAFs). Subsequently, we found that exosomal linc00881 secreted by OS cells can regulate the expression of matrix metalloproteinase 2 (MMP2) in HFL-1 cells by sponging miR-29c-3p, thereby activating the NF-κB signaling in lung fibroblasts. Finally, we discovered that pro-inflammatory cytokines, namely IL-1β, IL-6, and IL-8, were secreted through the linc00881/miR-29c-3p/MMP2 axis. These results suggest that OS-derived exosomes can mediate the intercellular crosstalk between OS cells and lung fibroblasts, ultimately impacting OS lung migration. Our study provides a potential target for the treatment of OS lung migration.

Hierarchically Structured Hydroxyapatite Particles Facilitate the Enhanced Integration and Selective Anti-Tumor Effects of Amphiphilic Prodrug for Osteosarcoma Therapy

Efficient delivery of cargo into target cells is a formidable challenge in modern medicine. Despite the great promise of biomimetic hydroxyapatite (HA) particles in tissue engineering, their potential applications in bone tumor therapy, particularly their structure-function relationships in cargo delivery to target cells, have not yet been well explored. In this study, biomimetic multifunctional composite microparticles (Bm-cMPs) are developed by integrating an amphiphilic prodrug of curcumin with hierarchically structured HA microspheres (Hs-hMPs). Then, the effects of the hierarchical structure of vehicles on the integration and delivery of cargo as well as the anti-osteosarcoma (OS) effect of the composite are determined. Different hierarchical structures of the vehicles strongly influence the self-assembly behavior of the prodrug. The flake-like crystals of Hs-hMPs enable the highest loading capacity and enhance the stability of the cargo. Compared to the normal cells, OS cells exhibit 3.56-times better uptake of flake-like Hs-hMPs, facilitating the selective anti-tumor effect of the prodrug. Moreover, Bm-cMPs suppress tumor growth and metastasis by promoting apoptosis and inhibiting cell proliferation and tumor vascularization. The findings shed light on the potential application of Bm-cMPs and suggest a feasible strategy for developing an effective targeted therapy platform using hierarchically structured minerals for OS treatment.

Combination of hsa_circ_0004674 and lncRNA OIP5‑AS1 as a novel clinical biomarker used to predict prognosis in patients with osteosarcoma

Osteosarcoma is a malignant tumor that predominantly occurs in children or adolescents under the age of 20 years old. Metastasis and chemotherapy resistance are two problems in the treatment of osteosarcoma, and the lack of definite biomarkers impairs the course of treatment. In recent years, non-coding RNA, as a biomarker of osteosarcoma, has become an area of research focus. The role of long non-coding RNAs (lncRNAs), such as lncRNA OIP5-AS1, and circular RNAs, such as hsa_circ_0004674, in osteosarcoma have previously been revealed, and the present study investigated their clinical significance. A total of 20 samples were collected from patients with osteosarcoma. The expression levels of lncRNA OIP5-AS1 and hsa_circ_0004674 were analyzed in tumor tissues and patient serum, and their associations with chemotherapy sensitivity, lung metastasis and prognosis were assessed. The results revealed that these two non-coding RNAs were significantly upregulated in the osteosarcoma tissues of patients compared with those in the adjacent tumor tissues. In addition, the expression levels of the two non-coding RNAs were increased in the serum of patients with osteosarcoma compared with those in patients with bone fractures (P<0.01). In patients with lung metastasis or chemotherapy resistance (tumor necrosis rate <90%), the expression levels of the two non-coding RNAs were similarly increased. By plotting the receiver operating characteristic curve, it was revealed that the combination of hsa_circ_0004674 and lncRNA OIP5-AS1 was better than ALP or either non-coding RNA alone in predicting chemotherapy sensitivity and metastasis. Kaplan-Meier survival analysis showed that, in patients with osteosarcoma, higher expression of both non-coding RNAs was associated with worse survival time (log-rank test P=0.006). In conclusion, the combination of hsa_circ_0004674 and lncRNA OIP5-AS1 may be used as a better biomarker than traditional biomarkers, such as ALP, in a clinical setting.

Identification of miR-3182 and miR-3143 target genes involved in the cell cycle as a novel approach in TNBC treatment: A systems biology approach

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with a poor prognosis, lacking therapeutic targets. miRNAs play crucial roles in TNBC through regulating various mechanisms, including cellular growth and proliferation. This study aims to identify critical target genes of two novel miRNAs (miR-3143 and miR-3182) involved in the cell cycle of TNBC as possible therapeutic targets and investigates their regulatory and therapeutic roles through a systems biology approach and in vitro experiment. Datasets related to the TNBC cell line (MDA-MB-231) were screened and retrieved, and Gene regulatory networks were constructed. Significant regulatory motifs were detected and analyzed using the FANMOD and Cytoscape analyzer, and the clusters and seeds were identified using the MCODE. Functional enrichment analysis was also performed using DAVID and STRING. The most critical genes were determined using the analysis of GRN motifs and PPI clusters. The essential genes involved in the cell cycle were selected and verified using the bc-GenExMiner v4.7. We overexpressed miR-3143 and miR-3182 in the MDA-MB-231 cell line using human umbilical cord mesenchymal stem cell (HUCMSC)-miRNA loaded exosomes, and the expression of the critical target genes was investigated using RT-qPCR. We identified eight critical genes as potential therapeutic targets. Their expression decreased by overexpression of miR-3143 and miR-3182 in RT-qPCR. The identified critical genes have probably significant roles in the pathogenesis of TNBC through the cell cycle. We suggest that the overexpression of miR-3143 and miR-3182 could be a new therapeutic candidate in TNBC and is worth more investigation.

LncRNA LBX2-AS1 impacts osteosarcoma sensitivity to JQ-1 by sequestering miR-597-3p away from BRD4

Objective

Recent knowledge concerning the significance of long non-coding RNA (lncRNA)-mediated ceRNA networks provides new insight into their possible roles as specific biomarkers for the treatment of osteosarcoma (OS). Thus, this study aims to clarify the functional relevance and mechanistic actions of lncRNA LBX2-AS1 in OS.

Methods

Differential analysis was performed by integrating the TCGA and GTEx databases. Cox regression analysis was then employed to assess the prognostic value of the model. The expression of lncRNA LBX2-AS1 and miR-597-3p was quantified in OS cell lines by qRT-PCR. The proliferation, migration, invasion, and apoptosis of OS cell lines in response to manipulated lncRNA LBX2-AS1 were evaluated by MTT, colony formation, transwell, Western blot, and flow cytometry assays. Luciferase activity was assayed to validate the reciprocal regulation between lncRNA LBX2-AS1 and miR-597-3p. The protein levels of BRD4 and EMT-related factors were examined by Western blot assay. Finally, tumor growth in response to LBX2-AS1 knockdown was evaluated in xenograft-bearing nude mice.

Results

By integrating the GTEx and TCGA databases, we identified 153 differentially expressed lncRNAs. Among them, 5 lncRNAs, RP11-535M15.1, AC002398.12, RP3-355L5.4, LBX2-AS1, and RP11.47A8.5, were selected to establish a model, which predicted the prognosis of OS. Higher lncRNA LBX2-AS1 expression was noted in OS tissues relative to that in normal tissues. Silencing lncRNA LBX2-AS1 facilitated apoptosis and curtailed proliferative, migratory, and invasive capacities of OS cells. Mechanistically, lncRNA LBX2-AS1 could elevate the expression of BRD4, an oncogene, by competitively binding to miR-597-3p. More importantly, knockdown of lncRNA LBX2-AS1 increased the sensitivity of OS cells to the BRD4 inhibitor JQ-1. Finally, the tumor growth of OS cell xenografts was constrained in vivo in the presence of lncRNA LBX2-AS1 knockdown.

Conclusion

In conclusion, lncRNA LBX2-AS1 promotes the growth of OS and represses the sensitivity to JQ-1 by sponging miR-597-3p to elevate the expression of BRD4.

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.

Long non-coding RNA DUXAP10 exerts oncogenic properties in osteosarcoma by recruiting HuR to enhance SOX18 mRNA stability

Recent studies have demonstrated that several long non-coding RNAs (lncRNAs) play an important role in the occurrence and development of osteosarcoma (OS). However, more lncRNAs and their mechanisms in regulating growth and migration of OS cells remain to be investigated. In this study, we identified an lncRNA called DUXAP10 by analysis of GEO data, which was significantly up-regulated in OS tissues and cell lines. Experiments in vitro revealed that lncRNA DUXAP10 promoted proliferation, migration, and invasion of OS cells and inhibited their apoptosis. We also demonstrated that DUXAP10 promoted the formation and growth of OS by tumor formation assay. Furthermore, SOX18 was identified as a critical downstream target of DUXAP10 by transcriptome RNA-seq. Mechanistically, DUXAP10 mainly localized in cytoplasm and could specifically bind to HuR to increase the stability of SOX18 mRNA. Meanwhile, SOX18 knockdown largely reversed increased proliferation of OS cells induced by DUXAP10 overexpression. Findings from this study indicate that lncRNA DUXAP10 can act as an oncogene in osteosarcoma by binding HuR to up-regulate the expression of SOX18 at a post-transcriptional level, which may provide a new target for OS clinical diagnosis and treatment.

LINC01128 facilitates the progression of pancreatic cancer through up-regulation of LDHA by targeting miR-561-5p

Background

Long non-coding RNAs (lncRNAs) regulate tumor development and metastasis in several types of cancers through various molecular mechanisms. However, the biological role of most lncRNAs in pancreatic cancer (PC) remains unclear. Here, we explored the expression, biological functions, and molecular mechanism of LINC01128 in PC.

Methods

Quantitive reverse transcription PCR was used to detect the expression level of LINC01128 in PC tissues and different PC cell lines. A loss-of-function and gain-of-function experiment was used to explore the biological effects of LINC01128 on PC carcinogenesis in vitro and in vivo. Western blot analysis, subcellular fractionation experiment, luciferase reporter gene assay, and MS2-RNA immunoprecipitation experiment were used to study the potential molecular mechanism of LINC01128 during carcinogenesis.

Results

The expression of LINC01128 was upregulated in PC tissues and cell lines, and overexpression of LINC01128 was significantly related to the poor prognosis of patients with PC. Furthermore, silencing LINC01128 significantly inhibited the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of PC cells in vitro and tumor growth in vivo, while LINC01128 overexpression promoted these processes. Further research showed that LINC01128 acted as a sponge for microRNA miR-561-5p, and lactate dehydrogenase A (LDHA) was the downstream target gene of miR-561-5p. It was also revealed that the expression of miR-561-5p in PC was decreased, and a negative correlation between miR-561-5p and LINC01128 was revealed. Based on rescue experiments, LDHA overexpression partially restored the inhibitory effect of LINC01128 knockdown on proliferation, migration, and invasion of PC cells.

Conclusions

LINC01128 promotes the proliferation, migration, invasion, and EMT of PC by regulating the miR-561-5p/LDHA axis, suggesting LINC01128 may be a new prognostic marker and therapeutic target in PC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02490-5.

Polygonum cuspidatum inhibits the growth of osteosarcoma cells via impeding Akt/ERK/EGFR signaling pathways

ABBREVIATIONS

CC: Closeness centrality; OS: Osteosarcoma; TCM: Traditional Chinese medicine; NSCLC: Non-small cell lung cancer; DC: Degree centrality; CHM: Chinese herb medicine; BC: Betweenness centrality.

Blood-Derived Extracellular Vesicle-Associated miR-3182 Detects Non-Small Cell Lung Cancer Patients

Simple Summary

Lung cancer is the leading cause of cancer-related death worldwide as patients are burdened with incredibly poor prognosis. Low survival rates are primarily attributed to lack of early detection and, therefore, timely therapeutic interventions. Late diagnosis is essentially caused by absent and non-specific symptoms, and compounded by inadequate diagnostic tools. We show here that a lung cancer biomarker, based on a simple blood test, might provide promising advantages for diagnostic assessment. Small extracellular vesicles (sEVs) are miniscule messengers that carry cancer biomarkers and are easily detected in the blood. We identify that the abundance of a specific micro-RNA, miR-3182, in these sEVs can be detected in the blood of lung cancer patients but not in controls with benign lung conditions. This demonstrates the potential use of miR-3182 as a biomarker for lung cancer diagnosis.

Abstract

With five-year survival rates as low as 3%, lung cancer is the most common cause of cancer-related mortality worldwide. The severity of the disease at presentation is accredited to the lack of early detection capacities, resulting in the reliance on low-throughput diagnostic measures, such as tissue biopsy and imaging. Interest in the development and use of liquid biopsies has risen, due to non-invasive sample collection, and the depth of information it can provide on a disease. Small extracellular vesicles (sEVs) as viable liquid biopsies are of particular interest due to their potential as cancer biomarkers. To validate the use of sEVs as cancer biomarkers, we characterised cancer sEVs using miRNA sequencing analysis. We found that miRNA-3182 was highly enriched in sEVs derived from the blood of patients with invasive breast carcinoma and NSCLC. The enrichment of sEV miR-3182 was confirmed in oncogenic, transformed lung cells in comparison to isogenic, untransformed lung cells. Most importantly, miR-3182 can successfully distinguish early-stage NSCLC patients from those with benign lung conditions. Therefore, miR-3182 provides potential to be used for the detection of NSCLC in blood samples, which could result in earlier therapy and thus improved outcomes and survival for patients.

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.

Long non-coding RNA HCG11 enhances osteosarcoma phenotypes by sponging miR-1245b-5p that directly inhibits plakophilin 2

Long non-coding RNA (lncRNA) HCG11 can regulate various cancers through the ceRNA network. However, its role in osteosarcoma (OS) remains unknown. The HOS and Saos-2 cell lines were used for in vitro analyses. HCG11 and plakophilin 2 (PKP2) silencers, a miR-1245b-5p mimic, and a miR-1245b-5p inhibitor were utilized for the regulation analysis of lncRNA HCG11, miR-1245b-5p, and PKP2. Cell Counting Kit-8, wound healing, and transwell assays were used for cell proliferation, migration, and invasion analyses, and caspase-3 activity assay was used to measure cell apoptosis. The expression levels of lncRNA HCG11, miR-1245b-5p, and PKP2 were evaluated by quantitative real-time PCR and Western blotting. The distribution of lncRNA HCG11 was assessed using the RNA-FISH assay. The sponging and targeting roles of HCG11 and PKP2 on miR-1245b-5p were confirmed by dual-luciferase reporter analysis. An RNA immunoprecipitation assay was used to assess the binding between lncRNA HCG11 and miRNA-1245b-5p. We found that the lncRNA HCG11 was significantly upregulated in OS. LncRNA HCG11 silencing inhibits OS progression by repressing cell proliferation, migration, and invasion, and promoting cell apoptosis. RNA-FISH analysis indicated that lncRNA HCG11 was located in the cytoplasm. Mechanistic experiments showed that lncRNA HCG11 sponges miR-1245b-5p and negatively regulates miR-1245b-5p expression. Upregulated lncRNA HCG11 promotes proliferation, migration, and invasion, and inhibits apoptosis by inhibiting miR-1245b-5p in OS cells. PKP2 was verified as a target gene of miR-1245b-5p. Upregulated PKP2 promotes proliferation, migration, and invasion, and inhibits apoptosis by inhibiting miR-1245b-5p in OS. In conclusion, the HCG11/miR-1245b-5p/PKP2 axis promotes OS expression by promoting cell proliferation, migration, and invasion, and inhibiting apoptosis.

lncRNA MELTF-AS1 facilitates osteosarcoma metastasis by modulating MMP14 expression

Osteosarcoma is a highly aggressive cancer common in children and adolescents. There is still a lack of effective treatments for metastatic or recurrent osteosarcoma. The role of long non-coding RNAs (lncRNAs) in osteosarcoma has gradually attracted attention. Here, we identified lncRNAs that were abnormally expressed in metastatic osteosarcoma through analyzing the sequencing data of osteosarcoma tissues and selected upregulated lncRNA MELTF-AS1 for detailed study. The qRT-PCR analysis showed that the expression of MELTF-AS1 was increased in osteosarcoma tissues and cells, and the high expression of MELTF-AS1 indicated a poor prognosis of osteosarcoma patients. The high expression of MELTF-AS1 in osteosarcoma was partly due to the transcriptional activation of RREB1. The results of transwell assays, scratch wound healing assays, and the tail vein injection lung metastasis model demonstrated that knocking down MELTF-AS1 inhibited metastasis ability of osteosarcoma cells. Furthermore, the results of RNA pull-down assays, luciferase reporter assays, and RNA immunoprecipitation (RIP) assays revealed that MELTF-AS1 could regulate MMP14 expression through interaction with miR-485-5p. Our study suggested that MELTF-AS1 functioned as a pro-metastasis gene in osteosarcoma by upregulating MMP14 and that it could be a potential therapeutic and diagnostic target for osteosarcoma.

Evaluating the influence of Human Umbilical Cord Mesenchymal Stem Cells-derived exosomes loaded with miR-3182 on metastatic performance of Triple Negative Breast Cancer cells

AIMS

Deregulation of microRNA (miRNA) function has been linked to numerous human cancers, such as Triple Negative Breast Cancer (TNBC). Exosomes, a subgroup of extracellular vehicles (EVs), can efficiently deliver many different cargo types to the target cell and have an extensive role in delivering therapeutic cargo for treatment. The present study intended to interrogate the effects of exosomal delivery of miR-3182 on TNBC cellular processes.

MAIN METHODS

Human Umbilical Cord Mesenchymal Stem Cells (HUCMSCs) were cultured and exosomes were isolated and characterized using TEM, SEM, DLS, and Western blot. Exosomes were transfected with miR-3182 and added to the treatment groups. The expression level of miR-3182 and their target genes including mTOR and S6KB1 were evaluated using RT-qPCR. The effects of miR-3182 loaded HUCMSC-exosomes treatment on the cellular aspect of MDA-MB-231 cells including their viability, migration potency, cell cycle status and apoptosis were investigated.

KEY FINDINGS

According to the results, exosomal miR-3182 significantly abolished cell proliferation and migration (P < 0.05). miR-3182 loaded exosomes also induced apoptosis in TNBC cells by down-regulating mTOR and S6KB1 genes (P < 0.05).

SIGNIFICANCE

In nutshell, miR-3182-loaded HUCMSC-exosomes can suppress TNBC invasion, suggesting that exosomes containing miR-3182 could be a reliable therapeutic paradigm in TNBC therapy.

Noncoding RNAs in tumor metastasis: molecular and clinical perspectives

Metastasis is the main culprit of cancer-associated mortality and involves a complex and multistage process termed the metastatic cascade, which requires tumor cells to detach from the primary site, intravasate, disseminate in the circulation, extravasate, adapt to the foreign microenvironment, and form organ-specific colonization. Each of these processes has been already studied extensively for molecular mechanisms focused mainly on protein-coding genes. Recently, increasing evidence is pointing towards RNAs without coding potential for proteins, referred to as non-coding RNAs, as regulators in shaping cellular activity. Since those first reports, the detection and characterization of non-coding RNA have explosively thrived and greatly enriched the understanding of the molecular regulatory networks in metastasis. Moreover, a comprehensive description of ncRNA dysregulation will provide new insights into novel tools for the early detection and treatment of metastatic cancer. In this review, we focus on discussion of the emerging role of ncRNAs in governing cancer metastasis and describe step by step how ncRNAs impinge on cancer metastasis. In particular, we highlight the diagnostic and therapeutic applications of ncRNAs in metastatic cancer.

The Vital Roles of LINC00662 in Human Cancers

Long non-coding RNAs (lncRNAs) play crucial roles in many human diseases, particularly in tumorigenicity and progression. Although lncRNA research studies are increasing rapidly, our understanding of lncRNA mechanisms is still incomplete. The long intergenic non-protein coding RNA 662 (LINC00662) is a novel lncRNA, and accumulating evidence suggests that it is related to a variety of tumors in multiple systems, including the respiratory, reproductive, nervous, and digestive systems. LINC00662 has been shown to be upregulated in malignant tumors and has been confirmed to promote the development of malignant tumors. LINC00662 has also been reported to facilitate a variety of cellular events, such as tumor-cell proliferation, invasion, and migration, and its expression has been correlated to clinicopathological characteristics in patients with tumors. In terms of mechanisms, LINC00662 regulates gene expression by interacting with both proteins and with RNAs, so it may be a potential biomarker for cancer diagnosis, prognosis, and treatment. This article reviews the expression patterns, biological functions, and underlying molecular mechanisms of LINC00662 in tumors.

DUXAP8 knockdown inhibits the development of melanoma by regulating the miR-3182/NUPR1 pathway

Double homeobox A pseudogene 8 (DUXAP8) has been reported to regulate the growth of several types of cancers, such as breast cancer and ovarian cancer. However, its role in melanoma remains unclear. In the present study, the mechanism through which DUXAP8 regulates melanoma progression was explored. The expression levels of DUXAP8 were determined in 43 samples from patients with melanoma in different stages, as well as human epidermal melanocytes cells and malignant melanoma cell lines using reverse transcription-quantitative PCR (RT-qPCR). The prognosis of patients was analyzed using the Kaplan-Meier method. The relationship between lncRNA DUXAP8 expression and microRNA (miR)-3182 or nuclear protein 1 transcriptional regulator (NUPR1) levels was analyzed using Pearson's correlation. Luciferase reporter and RNA pull-down were used to examine the interactions between these molecules. Proliferation was assessed using Cell Counting-Kit-8. Transwell assays were used to examine cell migration and invasion. lncRNA DUXAP8 was upregulated in melanoma tissue and cells compared with normal tissues and cells. The levels of DUXAP8 inversely correlated with survival time of patients with melanoma. Knockdown of lncRNA DUXAP8 inhibited proliferation, migration and invasion of melanoma cells. lncRNA DUXAP8 targeted miR-3182, while miR-3182 targeted NUPR1. The overexpression of NUPR1 reversed the effects of DUXAP8 knockdown or miR-3182 mimic on melanoma progression. In conclusion, lncRNA DUXAP8 downregulation inhibits the development of melanoma by regulating the miR-3182/NUPR1 axis.

LncRNA RUSC1-AS1 promotes osteosarcoma progression through regulating the miR-340-5p and PI3K/AKT pathway

Dysregulation of long noncoding RNA (lncRNA) is frequently involved in the progression and development of osteosarcoma. LncRNA RUSC1-AS1 is reported to be upregulated and acts as an oncogene in hepatocellular carcinoma, cervical cancer and breast cancer. However, its role in osteosarcoma has not been studied yet. In the present study, we investigated the role of RUSC1-AS1 in osteosarcoma both in vitro and in vivo. The results showed that the expression of RUSC1-AS1 was significantly upregulated in osteosarcoma cell line U2OS and HOS compared to that in human osteoblast cell line hFOB1.19. Similar results were found in human samples. Silencing RUSC1-AS1 by siRNA significantly inhibited U2OS and HOS cell proliferation and invasion, measured by CCK-8 and transwell assay. Besides, knockdown of RUSC1-AS1 increased cell apoptosis in osteosarcoma cell lines. In addition, RUSC1-AS1 promoted the epithelial-mesenchymal transition (EMT) process of osteosarcoma cells. In vivo experiments confirmed that RUSC1-AS1 knockdown had an inhibitory effect on osteosarcoma tumor growth. Mechanically, we showed that RUSC1-AS1 directly binds to and inhibits miR-340-5p and activates the PI3K/AKT signaling pathway. In conclusion, our study demonstrated that RUSC1-AS1 promoted osteosarcoma development both in vitro and in vivo through sponging to miR-340-5p and activating the PI3K/AKT signaling pathway. Therefore, RUSC1-AS1 becomes a potential therapeutic target for osteosarcoma.

LncRNA SNHG16 contributes to osteosarcoma progression by acting as a ceRNA of miR-1285-3p

Background

The long non-coding (lnc) RNA activated by small nucleolar RNA host gene 16 (SNHG16), which has been reported to play a vital role in a number of different types of cancer, is a novel lncRNA. However, following an osteosarcoma (OS) study, the expression pattern, biological roles, clinical values and potential molecular mechanism of SNHG16 remain unclear. In the current study, we aimed to examine its expression and possible function in osteosarcoma (OS).

Method

Cell proliferation was measured by colony formation assay and Cell Counting Kit-8 (CCK-8) in vitro, and xenograft transplantation assay in vivo. Meanwhile, we used transwell chambers to test cell migration and invasion was evaluated. Cell cycle and apoptosis was evaluated by flow cytometry assay. Immunoblotting and qPCR analysis was carried out to detect protein and gene expression, respectively. Luciferase reporter assay was used to predict the potential downstream genes.

Results

The present study demonstrated that SNHG16 is highly expressed in both the tissues of patients with OS, as well as OS cell lines, and its expression level was positively correlated with clinical stage and poor overall survival. Functional assays revealed that the depletion of SNHG16 inhibits OS growth, OS cell progression and promotes apoptosis both in vivo and in vitro. In addition, the present study revealed that microRNA-1285-3p expression levels can be decreased by SNHG16 acting as a ‘sponge’, and that this pathway takes part in OS tumor growth in vivo, and OS cell proliferation, invasion, migration and apoptosis in vitro.

Conclusions

The results from the present study demonstrate the role of lncRNA SNHG16 in OS progression, which is SNHG16 might exert oncogenic role in osteosarcoma (OS) by acting as a ceRNA of miR-1285-3p, and it may become a novel target in OS therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07933-2.

New Therapeutic Options for Advanced Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), one of the most common lethal diseases in the world, has a 5-year survival rate of only 7%. Hepatocellular carcinoma has no symptoms in the early stage but obvious symptoms in the late stage, leading to delayed diagnosis and reduced treatment efficacy. In recent years, as the scope of HCC research has increased in depth, the clinical development and application of molecular targeted drugs and immunotherapy drugs have brought new breakthroughs in HCC treatment. Targeted therapy drugs for HCC have high specificity, allowing them to selectively kill tumor cells and minimize damage to normal tissues. At present, these targeted drugs are mainly classified into 3 categories: small molecule targeted drugs, HCC antigen-specific targeted drugs, and immune checkpoint targeted drugs. This article reviews the latest research progress on the targeted drugs for HCC.

LINC01116 Promotes Doxorubicin Resistance in Osteosarcoma by Epigenetically Silencing miR-424-5p and Inducing Epithelial-Mesenchymal Transition

Background: Development of resistance to doxorubicin-based chemotherapy limits its curative effect in osteosarcoma. In the current study, we focused on investigating the mechanisms underlying the development of doxorubicin resistance in osteosarcoma.

Methods: The human osteosarcoma cell line MG-63 and doxorubicin-resistant MG-63/Dox cells were used in this study. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of the long non-coding RNA LINC01116 in the two cell lines. Then, the specific shRNA for LINC01116 was employed to suppress LINC01116 expression in MG-63/Dox cells. Cell viability was assessed by the CCK-8 and colony formation assays. Cell migration and invasion were evaluated by the transwell assay. Moreover, the epithelial-mesenchymal transition (EMT)-related proteins, E-cadherin, vimentin, and N-cadherin were evaluated by Western blotting. The regulation of LINC01116 on miR-424-5p expression was examined using methylation-specific PCR, RNA immunoprecipitation, and Western blotting assay. The potential targeting of HMGA2 by miR-424-5p was predicted using the bioinformatics databases TargetScan and miRanda and verified by a dual-luciferase reporter assay.

Results: LINC01116 was more highly expressed in MG-63/Dox cells than in MG-63 cells. Inhibition of LINC01116 suppressed cell viability, migration, and invasion, along with upregulating the expression of E-cadherin, downregulating vimentin, and attenuating doxorubicin resistance in MG-63/Dox cells. Further mechanism-related investigations indicated that LINC01116 regulated HMGA2 expression via the EZH2-associated silencing of miR-424-5p.

Conclusion: LINC01116 exerts regulatory effects on doxorubicin resistance through the miR-424-5p axis, providing a potential approach to overcoming chemoresistance in osteosarcoma.

The value of lncRNAs as prognostic biomarkers on clinical outcomes in osteosarcoma: a meta-analysis

Background

In recent years, emerging studies have demonstrated critical functions and potential clinical applications of long non-coding RNA (lncRNA) in osteosarcoma. To further validate the prognostic value of multiple lncRNAs, we have conducted this updated meta-analysis.

Methods

Literature retrieval was conducted by searching PubMed, Web of Science and the Cochrane Library (last update by October 2, 2019). A meta-analysis was performed to explore association between lncRNAs expression and overall survival (OS) of osteosarcoma patients. Relationships between lncRNAs expression and other clinicopathological features were also analyzed respectively.

Results

Overall, 4351 patients from 62 studies were included in this meta-analysis and 25 lncRNAs were identified. Pooled analyses showed that high expression of 14 lncRNAs connoted worse OS, while two lncRNAs were associated with positive outcome. Further, analysis toward osteosarcoma clinicopathologic features demonstrated that overexpression of TUG1 and XIST indicated poor clinical parameters of patients.

Conclusions

This meta-analysis has elucidated the prognostic potential of 16 lncRNAs in human osteosarcoma. Evidently, desperate expression and functional targets of these lncRNAs offer new approaches for prognosis and therapy of osteosarcoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07882-w.

Role of long non-coding RNAs on the regulation of Nrf2 in chronic diseases

Studies have identified dysregulated long non-coding RNA (lncRNA) in several diseases at transcriptional, translational, and post-translational levels. Although our mechanistic knowledge on the regulation of lncRNAs is still limited, one of the mechanisms of action attributed is binding and regulating transcription factors, thus controlling gene expression and protein function. One such transcription factor is nuclear factor erythroid 2-related factor 2 (Nrf2), which plays a critical biological role in maintaining cellular homeostasis at multiple levels in physiological and pathophysiological conditions. The levels of Nrf2 were found to be down-regulated in many chronic diseases, signifying that Nrf2 can be a key therapeutic target. Few lncRNAs like lncRNA ROR, ENSMUST00000125413, lncRNA ODRUL, Nrf2-lncRNA have been associated with the Nrf2 signaling pathway in response to various stimuli, including stress. This review discusses the regulation of Nrf2 in different responses and the potential role of specific lncRNA in modulating its transcriptional activities. This review further helps to enhance our knowledge on the regulatory role of the critical antioxidant transcription factor, Nrf2.

lncRNA TUSC7 inhibits osteosarcoma progression through the miR‑181a/RASSF6 axis

Osteosarcoma (OS) is one of the most aggressive malignancies, accompanied by an elevated incidence and a decreased rate of healing. Recently, several long non-coding RNAs (lncRNAs) have been reported to be involved in OS progression. Although tumor suppressor candidate 7 (TUSC7) was reported as a novel lncRNA, little is known about its biological functions in OS. The present study was designed to explore whether TUSC7 was involved in the pathological development of OS using various methods, including hematoxylin and eosin staining, Cell Counting Kit-8 assay, colony formation assay and Transwell assay. The present study revealed that TUSC7 expression was downregulated in OS tissues and cell lines compared with in normal tissues and cell lines. Functionally, the current results revealed that overexpression of TUSC7 inhibited OS cell proliferation, migration and invasion, while promoting apoptosis in vitro and in vivo. Next, the subcellular distribution of TUSC7 was examined by nuclear/cytoplasmic RNA fractionation and reverse transcription-quantitative PCR. Mechanistic studies revealed that TUSC7 exerted its role by sponging microRNA (miR)-181a in OS cell lines. Ras association domain family member 6 (RASSF6) was confirmed as a target gene of miR-181a, and the expression levels of RASSF6 were negatively regulated by miR-181a. Additionally, the results of rescue experiments suggested that overexpression of miR-181a neutralized the inhibitory effects of TUSC7 overexpression on OS cells. Overall, the present study demonstrated that the tumor suppressor role of TUSC7 in OS progression was mediated through the miR-181a/RASSF6 axis, which may represent a new therapeutic target for OS.

LncRNA SOX21-AS1 Promotes the Growth and Invasiveness of Osteosarcoma Cells Through miR-7-5p/IRS2 Regulatory Network

BACKGROUND

Osteosarcoma (OS) is commonly known as a bone malignancy, causing a mass of lethality worldwide. Long coding RNAs (lncRNAs) have been widely reported by documents that they exert important functions in the development of cancers. However, the relative mechanism of lncRNA SOX21-AS1 needs to be fully discovered in OS, as it has never been studied in the past.

AIM OF THE STUDY

To find out how SOX21-AS1 materializes its function in OS.

METHODS

qRT-PCR detected RNA expression, and western blot tested the protein level. CCK8 and TUNEL assays were performed to assess cell viability and apoptosis. Next, Transwell analyses were applied to identify OS cell migration and invasion. Luciferase reporter, RIP and RNA pull-down experiments were employed for investigating the relationships among RNAs.

RESULTS

SOX21-AS1 had high expression in OS, and its presence accelerated OS cell proliferation, migration and invasion. Interestingly, we evidenced that SOX21-AS1 sponged miR-7-5p, which then targeted IRS2 in OS cells. SOX21-AS1 competed with IRS2 in binding to miR-7-5p, which formulated the ceRNA signaling in OS. SOX21-AS1 could negatively regulate miR-7-5p expression. Rescue experiments certified that the enhancement of IRS2 would neutralize the inhibition of SOX21-AS1 depletion on OS cell proliferation and metastasis.

CONCLUSIONS

SOX21-AS1 enhances IRS2 level by absorbing miR-7-5p, so as to boost the progression of OS.

Role of microRNAs in the crosstalk between osteosarcoma cells and the tumour microenvironment

Osteosarcoma (OS) is the most common primary bone tumour, with a peak incidence in adolescents, and the five-year survival rate of patients with metastasis or recurrence is much lower than that of patients without metastasis and recurrence. OS is initiated and develops in a complex tumour microenvironment (TME) that contains many different components, such as osteoblasts, osteoclasts, mesenchymal stem cells, fibroblasts, immune cells, extracellular matrix (ECM), extracellular vesicles, and cytokines. The extensive interaction between OS and the TME underlies OS progression. Therefore, rather than targeting OS cells, targeting the key factors in the TME may yield novel therapeutic approaches. MicroRNAs (miRNAs) play multiple roles in the biological behaviours of OS, and recent studies have implied that miRNAs are involved in mediating the communication between OS cells and the surrounding TME. Here, we review the TME landscape and the miRNA dysregulation of OS, describe the role of the altered TME in OS development and highlight the role of miRNA in the crosstalk between OS cells and the TME.

TNK2-AS1 upregulated by YY1 boosts the course of osteosarcoma through targeting miR-4319/WDR1

Mounting research papers have suggested that long non-coding RNAs (lncRNAs) elicit important functions in the progression of osteosarcoma (OS). This study focused on the role of TNK2-AS1 in OS. TNK2-AS1 was powerfully expressed in OS tissues and cell lines. In addition, TNK2-AS1 downregulation inhibited proliferative, migratory, and invasive capacities while promoting apoptosis in OS cells. miR-4319 was removed by TNK2-AS1 and therefore TNK2-AS1 elevated WDR1 expression in OS cells. miR-4319 had an inhibitory influence on OS progression, while WDR1 was a contributor to OS progression. Rescue assays certified that TNK2-AS1 promoted malignant phenotypes in vitro and the growth in vivo of OS cells by upregulating WDR1. In depth, we found that YY1 accelerated the transcription of TNK2-AS1 in OS cells, and that its role in OS also depended on TNK2-AS1-regulated WDR1. In conclusion, TNK2-AS1 was positively modulated by YY1 and aggravated the development of OS by 'sponging' miR-4319 to elevate WDR1. The findings highlighted that TNK2-AS1 might be a promising target for the treatment of OS.

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.

Characterization of LncRNA SNHG22 as a protector of NKIRAS2 through miR-4492 binding in osteosarcoma

Many studies have revealed the function of long noncoding RNA (LncRNA) in regulating tumorigenesis of osteosarcoma (OS). As a subgroup of LncRNA, small nucleolar RNA host genes (SNHGs) have emerged as potentially important in OS. According to our recent findings, small nucleolar RNA host gene 22 (SNHG22) plays an important role in inhibiting the growth and metastasis of OS. However, the underlying mechanism of SNHG22 in regulating OS progression remains unknown. In this study, we confirmed that SNHG22 was downregulated in OS, and the overexpression of SNHG22 significantly inhibited OS progression in vivo and in vitro. Meanwhile, overexpression of SNHG22 also inhibited the migration and proliferation of human umbilical vein endothelial cells (HUVECs) and prevented the epithelial-to-mesenchymal transition (EMT) in OS. Furthermore, the interaction between miR-4492 and SNHG22 we previously predicted was validated by RNA pull-down assays and RNA immunoprecipitation assays. Dual-luciferase reporter assays showed that SNHG22 could directly interact with miR-4492 and upregulate the expression of NK-κB inhibitor-interacting Ras-like 2 (NKIRAS2) by its competing endogenous RNA (ceRNA) activity on miR-4492. In conclusion, our study has clarified the function of SNHG22 in OS progression and suggests a novel therapeutic target for OS.

miR-199b-5p promoted chondrogenic differentiation of C3H10T1/2 cells by regulating JAG1

Mesenchymal stem cells (MSCs) are considered a promising candidate for use in cell-based therapy for cartilage repair. To promote understanding of the molecular control of chondrogenesis differentiation in MSCs, we compared the changes in microRNAs during in vitro chondrogenesis process of human bone-marrow mesenchymal stem cells (hBMSCs). MiR-199b-5p was up-regulated significantly during this process. The aim of the study was to investigate the effects of miR-199b-5p on chondrogenic differentiation of C3H10T1/2 MSC cells and explore the underlying mechanisms. MiR-199b-5p mimics or inhibitor were transfected into C3H10T1/2 cells, respectively, and then, the effects of miR-199b-5p on chondrogenic differentiation of C3H10T1/2 cells were detected. The results indicated that miR-199b-5p overexpression inhibited the growth of C3H10T1/2 cells but promoted transforming growth factor-β3 (TGF-β3)-induced C3H10T1/2 cells of chondrogenic differentiation, as supported by enhancing the gene and protein expression of chondrocyte specific markers of SOX9, aggrecan, and collagen type II (Col2a1). In contrast, inhibiting miR-199b-5p notably promoted the proliferation of C3H10T1/2 cells but decreased chondrogenic differentiation. Furthermore, mechanism studies revealed that JAG1 was a direct target of miR-199b-5p by dual luciferase reporter assays. While silencing of JAG1 by isRNA resulted an increase of chondrogenic differentiation. Further, JAG1 knockdown was demonstrated to block the effect of miR-199b-5p inhibition. In conclusion, the present study revealed for the first time that miR-199b-5p was the positive regulators to modulate chondrogenic differentiation of C3H10T1/2 cells by targeting JAG1. These findings may provide a novel insight on miRNA-mediated MSC therapy for cartilage related disorders.

The role and clinical significance of long noncoding RNA zinc finger E-box-binding homeobox two antisense RNA 1 in promoting osteosarcoma cancer cell proliferation, inhibiting apoptosis and increasing migration by regulating miR-145

We aimed to investigate the expression level of long noncoding RNA (lncRNA) zinc finger E-box-binding homeobox two antisense RNA 1 (ZEB2-AS1) in osteosarcoma and explore its possible regulatory mechanisms. Expression of lncRNA ZEB2-AS1 was detected by quantitative real-time PCR in 63 cancerous tissues and 25 adjacent normal mucosal tissues from patients with osteosarcoma. The correlation between the lncRNA ZEB2-AS1 level and clinicopathological characteristics of the osteosarcoma patients were evaluated, and 5-year overall survival (5OS) was also analyzed according to lncRNA ZEB2-AS1 expression. The ZEB2-AS1 and miR-145 recombinant expression vector was used to analyze their relationship in an in vitro cell system. Luciferase reporter gene assays and RNA immunoprecipitation assays were used to verify the interaction between ZEB2-AS1 and miR-145. The proliferation, apoptosis and migration of osteosarcoma cells were determined by Cell counting kit-8 assays, Annexin V-PI assays and transwell assays, respectively. A significantly increased level of lncRNA ZEB2-AS1 with a fold change of 3.86 was found in osteosarcoma tissues compared with control tissues (P < 0.001). The Chi-square test revealed that lncRNA ZEB2-AS1 expression in osteosarcoma was significantly different according to radiology classification (P = 0.018), TNM stage (P = 0.000) and survival status (P = 0.005). The 5OS was 18.4% and 52% in osteosarcoma patients with higher and lower lncRNA ZEB2-AS1 expression, respectively. Significantly increased ZEB2-AS1 expression was found in osteosarcoma cells, while decreased levels of miR-145 were confirmed in osteosarcoma tissues and cell lines compared to controls. Moreover, a negative correlation was found between the expression level of ZEB2-AS1 and miR-145 in osteosarcoma tissues (R2 = 0.71, P < 0.01). ZEB2-AS1 knockdown resulted in decreased osteosarcoma cell proliferation, increased apoptosis and reduced migration. In addition, negative regulation of miR-145 by ZEB2-AS1 in osteosarcoma cells was also observed, and the effects of ZEB2-AS1 on osteosarcoma cells were found to be regulated by miR-145. Significantly upregulated lncRNA ZEB2-AS1 expression in osteosarcoma patients influences the prognosis of patients, and ZEB2-AS1 accelerates tumorigenesis and osteosarcoma development by downregulating miR-145.

Long non-coding RNA PGM5-AS1 promotes epithelial-mesenchymal transition, invasion and metastasis of osteosarcoma cells by impairing miR-140-5p-mediated FBN1 inhibition

Osteosarcoma is an uncommon tumor occurring in bone, accompanied by elevated incidence and reduced rate of healing. Epithelial‐to‐mesenchymal transition (EMT) serves as a conceptual paradigm to explain the invasion and metastasis of osteosarcoma and other cancers. Hence, developing effective therapeutic strategy to treat the EMT of osteosarcoma is essential. Here, we identified the molecular mechanism of long noncoding RNA (lncRNA) PGM5‐AS1 in EMT and progression of osteosarcoma. Microarray‐based analysis was employed to screen the osteosarcoma‐related differentially expressed lncRNAs. The levels of PGM5‐AS1 as well as microRNA‐140‐5p (miR‐140‐5p) and fibrillin‐1 (FBN1) in osteosarcoma tissues and cells were determined. Dual‐luciferase reporter gene assay, RNA pull‐down assay, and RNA immunoprecipitation assay were conducted to validate the relationship among PGM5‐AS1, miR‐140‐5p, and FBN1. Expression of PGM5‐AS1, miR‐140‐5p, and FBN1 was altered by overexpression, shRNA, mimic, or inhibitors in order to investigate how they regulated migration, invasion, and EMT of osteosarcoma cells in vitro. Loss‐ and gain‐of‐function approaches were employed in nude mice to detect their roles in tumorigenesis in vivo. Osteosarcoma tissues and cells exhibited low expression of miR‐140‐5p, but high expression of PGM5‐AS1 and FBN1. PGM5‐AS1 competitively bound to miR‐140‐5p to upregulate FBN1. Furthermore, hindering PGM5‐AS1 and FBN1 or overexpressing miR‐140‐5p dampened migration, invasion, and EMT of osteosarcoma cells in vitro. Furthermore, silencing PGM5‐AS1 or FBN1, or overexpressing miR‐140‐5p markedly inhibited tumorigenesis in nude mice in vivo. Taken together, PGM5‐AS1 depletion causes FBN1 reduction to retard osteosarcoma processes by negatively modulating miR‐140‐5p.

LINC00662 Long Non-Coding RNA Knockdown Attenuates the Proliferation, Migration, and Invasion of Osteosarcoma Cells by Regulating the microRNA-15a-5p/Notch2 Axis

Purpose

Osteosarcoma (OS) is a frequently occurring malignancy in children and adolescents. In this study, we aimed to investigate the effects of the long non-coding RNA (lncRNA) LINC00662 (LINC00662) in OS and the underlying molecular mechanism.

Methods

The expression of LINC00662, microRNA-15a-5p (miR-15a-5p), and Notch2 in OS was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The proliferation, migration, and invasion of OS cells were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), wound-healing, and transwell assay. The interactions among LINC00662, miR-15a-5p, and Notch2 were determined by dual-luciferase reporter assays. A tumor xenograft model was established in mice for evaluating tumor growth in vivo.

Results

The expression of LINC00662 and Notch2 was found to be upregulated in OS, but the expression of miR-15a-5p was downregulated. The results demonstrated that LINC00662 knockdown attenuated the proliferation, migration, and invasion of OS cells and suppressed tumor growth in mice. The study further demonstrated that LINC00662 directly interacted with miR-15a-5p, and that Notch2 was a target of miR-15a-5p. The inhibition of miR-15a-5p or Notch2 overexpression markedly reversed the suppressive effect of sh-LINC00662 on the proliferation, migration, and invasion of OS cells.

Conclusion

The study demonstrated that LINC00662 could be a potential biomarker for OS therapy, and LINC00662 knockdown suppressed the proliferation, migration, and invasion of OS cells by regulating the miR-15a-5p/Notch2 axis.

SPAG5 promotes osteosarcoma metastasis via activation of FOXM1/MMP2 axis

Osteosarcoma (OS) is a primary malignancy of bone with a tendency to metastasize early. An understanding of the pathways that regulate OS metastasis is required for the design of novel treatment approaches. Sperm-associated antigen 5 (SPAG5) is upregulated and functions as a potential tumor promoter in diverse human cancers, but has yet to be investigated in the OS. In the present study, results showed that SPAG5 expression is upregulated in OS tissues, and SPAG5 overexpression is obviously associated with the malignant phenotype and poor survival in patients with OS. Multivariate analyses also revealed that SPAG5 overexpression is an independent prognostic factor for poor outcome of patients with OS. The functional assay indicated that SPAG5 silencing significantly inhibits the invasion and migration of OS cells in vitro. Additionally, knockdown of SPAG5 in OS cells suppresses lung metastasis in vivo. Further, we also found that SPAG5 silencing inhibits the epithelial-mesenchymal transition (EMT) process of OS cells. Moreover, our results indicated that SPAG5 promotes OS metastasis by increasing matrix metalloproteinase-2 (MMP2) expression, and demonstrated that MMP2 is crucial for the pro-metastasis role of SPAG5 in OS cells. Mechanistically, we identified that SPAG5 regulates MMP2 expression by modulating FOXM1 (Forkhead box M1) degradation to enhance the protein stability of FOXM1. Collectively, these findings describe the effects of SPAG5-FOXM1-MMP2 axis in the regulation of OS cell migration and metastasis formation. We provide a novel evidence that SPAG5 may serve as a prognostic indicator and potential therapeutic target for patients with osteosarcoma.

Targeting Long Non-coding RNA to Therapeutically Regulate Gene Expression in Cancer

Long-chain non-coding RNAs (lncRNAs) are RNA molecules with a length greater than 200 nt and no function of encoding proteins. lncRNAs play a precise regulatory function at different levels of transcription and post-transcription, and they interact with various regulatory factors to regulate gene expression, and then participate in cell growth, differentiation, apoptosis, and other life processes. In recent years, studies have shown that the abnormal expression of lncRNAs is closely related to the occurrence and development of tumors, which is expected to become an effective biomarker in tumor diagnosis. The sequencing analysis of mutations in the whole tumor genome suggests that mutations in non-coding regions may play an important role in the occurrence and development of tumors. Therefore, in-depth study of lncRNAs is helpful to clarify the molecular mechanism of tumor occurrence and development and to provide new targets for tumor diagnosis and treatment. This review introduces the molecular mechanism and clinical application prospect of lncRNAs affecting tumor development from the perspective of gene expression and regulation.

Research progress regarding the role of long non-coding RNAs in osteosarcoma

Osteosarcoma is a malignant tumor that occurs in children and adolescents. Although treatments for osteosarcoma have improved, the likelihood of survival remains low for most patients with metastasis and recurrence. Elucidating the mechanism underlying the development of osteosarcoma and chemotherapy resistance will be important to improve diagnosis and treatment. Long non-coding RNAs (lncRNAs), which are longer than 200 nucleotides in length and do not encode for proteins, have been shown to play a regulatory role in the occurrence and development of osteosarcoma, and are expected to serve as biomarkers and molecular targets. This review discusses the progress in the study of the role of lncRNAs in osteosarcoma, and highlights the recent developments in this field.

Enoxacin inhibits proliferation and invasion of human osteosarcoma cells and reduces bone tumour volume in a murine xenograft model

Osteosarcoma is the most prevalent primary bone malignancy in children and adolescents. Neoadjuvant chemotherapy combined with surgical resection, the current standard treatment of osteosarcoma, is associated with a 5-year survival rate of only ~70%. Therefore, it is necessary to identify new, more effective treatment strategies for patients with this lethal disease. Enoxacin is a highly effective broad-spectrum fluoroquinolone antibiotic with low toxicity. The drug inhibits the growth and metastasis of numerous tumour types, but its efficacy has not been studied in osteosarcoma. This study assessed the antitumour effects of enoxacin in osteosarcoma 143B cells and in a murine tumour xenograft model. Enoxacin inhibited the proliferation, invasion and migration of 143B cells, as well as inducing their apoptosis. These effects were thought to be mediated by downregulation of Bcl-xL, Bxl-2, matrix metalloproteinase (MMP)2 and MMP9 expression. Enoxacin also significantly impaired the growth of bone tumours in nude mice without affecting their liver or kidney function, or blood cell count. Collectively, these results indicate that enoxacin is a promising new drug for osteosarcoma that warrants further evaluation in clinical studies.

Mechanisms of Long Non-Coding RNAs in Cancers and Their Dynamic Regulations

Long non-coding RNA (lncRNA), which is a kind of noncoding RNA, is generally characterized as being more than 200 nucleotide transcripts in length. LncRNAs exhibit many biological activities, including, but not limited to, cancer development. In this review, a search of the PubMed database was performed to identify relevant studies published in English. The term "lncRNA or long non-coding RNA" was combined with a range of search terms related to the core focus of the review: mechanism, structure, regulation, and cancer. The eligibility of the retrieved studies was mainly based on the abstract. The decision as to whether or not the study was included in this review was made after a careful assessment of its content. The reference lists were also checked to identify any other study that could be relevant to this review. We first summarized the molecular mechanisms of lncRNAs in tumorigenesis, including competing endogenous RNA (ceRNA) mechanisms, epigenetic regulation, decoy and scaffold mechanisms, mRNA and protein stability regulation, transcriptional and translational regulation, miRNA processing regulation, and the architectural role of lncRNAs, which will help a broad audience better understand how lncRNAs work in cancer. Second, we introduced recent studies to elucidate the structure of lncRNAs, as there is a link between lncRNA structure and function and visualizing the architectural domains of lncRNAs is vital to understanding their function. Third, we explored emerging evidence for regulators of lncRNA expression, lncRNA turnover, and lncRNA modifications (including 5-methylcytidine, N6-methyladenosine, and adenosine to inosine editing), highlighting the dynamics of lncRNAs. Finally, we used autophagy in cancer as an example to interpret the diverse mechanisms of lncRNAs and introduced clinical trials of lncRNA-based cancer therapies.

Exosome-transmitted circ_MMP2 promotes hepatocellular carcinoma metastasis by upregulating MMP2

Exosomes released by tumor cells have been recently identified as important determinants of tumor progression. They often carry circular RNAs that are differentially expressed in tumors and may regulate tumorigenesis and metastasis. Here, we showed that supernatant of 97H hepatocellular carcinoma (HCC) cell line could promote metastasis in L02 human liver cells and HCC cell lines. Moreover, we determined that circ_MMP2 (has_circ_0039411) could be delivered by 97H‐ or LM3 cell‐derived exosomes to L02 and HepG2 cell cultures. High expression of circ_MMP2 led to the upregulation of its host gene matrix metallopeptidase 2 (MMP2) via the sponging of miR‐136‐5p. Rescue assays demonstrated that miR‐136‐5p and MMP2 were two essential participants in HCC metastasis. Finally, high level of circ_MMP2 or MMP2, as well as low level of miR‐136‐5p, was correlated with low overall survival of HCC patients. Our study highlights a novel molecular pathway in HCC cell‐derived exosomes.

Long noncoding RNA HIF1A-AS2 facilitates cell survival and migration by sponging miR-33b-5p to modulate SIRT6 expression in osteosarcoma

Long noncoding RNAs (lncRNAs) are emerging as vital regulators in various physiological and pathological processes. It was recently found that lncRNA HIF1A-AS2 could play oncogenic roles in several cancers. However, the function and regulatory mechanism of lncRNA HIF1A-AS2 in osteosarcoma (OS) remain largely unclear. In this study, we demonstrated that HIF1A-AS2 was overexpressed in OS tissues and cells. Downregulation of HIF1A-AS2 significantly affects multiple biological functions in OS cells, including cell proliferation, cell cycle progression, cell apoptosis, cell migration, and cell invasiveness. Mechanistic investigations demonstrated that HIF1A-AS2 can interact with miR-33b-5p and negatively regulate its expression, thereby upregulating the protein expression of miR-33b-5p’s target SIRT6. Additionally, in vivo experiments using a xenograft tumor mouse model revealed that downregulation of HIF1A-AS2 suppresses tumor growth in OS. Taken together, a newly identified regulatory mechanism for the lncRNA HIF1A-AS2–miR-33b-5p–SIRT6 axis was systematically studied in OS, which could be a promising target for the treatment of OS.

LncRNA MAGI2-AS3 Is Regulated by BRD4 and Promotes Gastric Cancer Progression via Maintaining ZEB1 Overexpression by Sponging miR-141/200a

Long non-coding RNAs (lncRNAs) play critical roles in tumorigenesis and tumor progression. However, the biological function of most lncRNAs remains unknown in human gastric cancer. This study here aims to explore the unknown function of lncRNA MAGI2-AS3 in gastric cancer. First, bioinformatics analysis showed that lncRNA MAGI2-AS3 was overexpressed in gastric cancer tissues, and the overexpression of MAGI2-AS3 has been shown to be associated with poor prognosis in all three independent gastric cancer cohorts (The Cancer Genome Atlas stomach cancer [TCGA_STAD], GEO: GSE62254 and GSE15459). The multivariate analysis indicated that lncRNA MAGI2-AS3 was an independent prognostic factor for both overall survival and disease-free survival of gastric cancer patients. Moreover, MAGI2-AS3 was identified to be an epithelial-mesenchymal transition (EMT)-related lncRNA and was highly co-expressed with ZEB1/2 in both gastric cancer tissues and normal stomach tissues. Loss-of-function and gain-of-function studies showed that lncRNA MAGI2-AS3 could positively regulate ZEB1 expression and the process of cell migration and invasion in gastric cancer. Subcellular location assay showed that lncRNA MAGI2-AS3 was mainly located in the cytoplasm of gastric cancer cells. Bioinformatics analysis and functional experiments revealed that lncRNA MAGI2-AS3 was negatively correlated with miR-141/200a expression and negatively regulated miR-141/200a-3p expression in gastric cancer. Therefore, we speculate that lncRNA MAGI2-AS3 promotes tumor progression through sponging miR-141/200a and maintaining overexpression of ZEB1 in gastric cancer. Nevertheless, we identified that BRD4 is a transcriptional regulator of lncRNA MAGI2-AS3 in gastric cancer. Additionally, our findings highlight that lncRNA MAGI2-AS3 is an ideal biomarker and could be a potential therapeutic target for gastric cancer.

LINC00858 promotes retinoblastoma cell proliferation, migration and invasion by inhibiting miR-3182

The aim of the present study was to determine the role of long intergenic non-protein coding RNA 858 (LINC00858) in retinoblastoma (RB) and investigate the underlying molecular mechanisms. RB tissues and paracancerous tissues of 27 RB cases were obtained. RB cell lines (SO-RB50, Y79, HXO-RB44 and WERI-Rb1) and a normal retinal epithelial cell line (ARPE-19) were cultured for in vitro experiments. Batches of SO-RB50 and Y79 cells were assigned to groups transfected with small interfering RNA targeting LINC00858 (si-LINC00858 group), microRNA (miR)-3182 mimics or inhibitor, or the respective controls. A Cell Counting Kit-8 and Transwell assays were performed to assess the effect of the transfections on the proliferation, migration and invasion of SO-RB50 and Y79 cells. A luciferase reporter assay was performed using SO-RB50 cells to demonstrate the direct binding of LINC00858 and miR-3182. Reverse transcription-quantitative PCR was employed to detect LINC00858 and miR-3182 expression. Pearson correlation analysis was used to assess the correlation between the expression of LINC00858 and miR-3182. The results indicated that RB tissues and cells exhibited aberrantly elevated LINC00858 expression (P<0.05). Compared with those in the control-transfected group, SO-RB50 and Y79 cells of the si-LINC00858 group had a lower cell proliferation, as well as a lower number of migrated and invaded cells (all P<0.05). miR-3182 was proven to be a target gene of LINC00858, to be abnormally downregulated in RB tissues and cells (P<0.05) and to be negatively correlated with LINC00858 expression. Compared with those in the si-LINC00858 + inhibitor-negative control group, SO-RB50 and Y79 cells of the si-LINC00858 + miR-3182 inhibitor group exhibited a significantly higher relative proliferation, migration and invasion (all P<0.05). In conclusion, LINC00858 promoted RB cell proliferation, migration and invasion, at least partially by inhibiting miR-3182.

miRNA signatures in childhood sarcomas and their clinical implications

Progresses in multimodal treatments have significantly improved the outcomes for childhood cancer. Nonetheless, for about one-third of patients with Ewing sarcoma, rhabdomyosarcoma, or osteosarcoma steady remission has remained intangible. Thus, new biomarkers to improve early diagnosis and the development of precision-targeted medicine remain imperative. Over the last decade, remarkable progress has been made in the basic understanding of miRNAs function and in interpreting the contribution of their dysregulation to cancer development and progression. On this basis, this review focuses on what has been learned about the pivotal roles of miRNAs in the regulation of key genes implicated in childhood sarcomas.

Proscillaridin A induces apoptosis and inhibits the metastasis of osteosarcoma in vitro and in vivo

The side effects of chemotherapy, drug resistance, and tumor metastasis hinder the development of treatment for osteosarcoma, leading to poor prognosis of patients with the disease. Proscillaridin A, a kind of cardiac glycoside, has been proven to have anti-proliferative properties in many malignant tumors, but the efficacy of the drug in treating osteosarcoma is unclear. In the present study, we assessed the effects of Proscillaridin A on osteosarcoma and investigated its underlying action mechanism. The cell cytotoxicity assay showed that Proscillaridin A significantly inhibited the proliferation of 143B cells in a dose- and time-dependent manner. Also, flow cytometry and invasion assay revealed that Proscillaridin A induced apoptosis and reduced 143B cell motility. Western blotting and PCR were used to detect the expressions of Bcl-xl and MMP2 and showed that mRNA/protein expression levels decreased significantly in Proscillaridin A-treated osteosarcoma cells. Using a mouse xenograft model, we found that Proscillaridin A treatment significantly inhibited tumor growth and lung metastasis in vivo and decreased the expression levels of Bcl-xl and MMP2. No noticeable side effect was observed in the liver, kidney, and hematological functions. Conclusively, Proscillaridin A suppressed proliferation, induced apoptosis, and inhibited 143B cell metastasis in vitro and in vivo, and these effects could be mediated by downregulating the expressions of Bcl-xl and MMP2.