Fibronectin-1 modulated by the long noncoding RNA OIP5-AS1/miR-200b-3p axis contributes to doxorubicin resistance of osteosarcoma cells

Research progress on the role of lncRNA, circular RNA, and microRNA networks in regulating ferroptosis in osteosarcoma

Noncoding RNAs (ncRNAs) do not participate in protein-coding. Ferroptosis is a newly discovered form of cell death mediated by reactive oxygen species and lipid peroxidation. Recent studies have shown that ncRNAs such as microRNAs, long noncoding RNAs, circular RNAs, and ferroptosis are involved in the occurrence and development of osteosarcoma (OS). Studies have confirmed that ncRNAs participate in the development of OS by regulating the ferroptosis. However, systematic summary on this topic are still lacking. This review summarises the potential role of ncRNAs in the diagnosis, treatment, drug resistance, and prognosis of OS and the basis for diagnosing, preventing, and treating clinical OS and developing effective drugs. This review summarises the latest research progress on ncRNAs that regulate ferroptosis in OS, attempts to clarify the molecular mechanisms by which ncRNAs regulate ferroptosis in the pathogenesis of OS, and elaborates on the involvement of ferroptosis in OS from the perspective of ncRNAs.

miR-1-3p Inhibits Osteosarcoma Cell Proliferation and Cell Cycle Progression While Promoting Cell Apoptosis by Targeting CDK14 to Inactivate Wnt/Beta-Catenin Signaling

Osteosarcoma (OS) is a common bone malignancy and is diagnosed frequently in children and young adults. According to previous RNA sequencing, miR-1-3p is downregulated in OS clinical samples. Nevertheless, the functions of miR-1-3p in OS cell process and the related mechanism have not been revealed yet. In the current study, miR-1-3p expression in OS tissues and cells were evaluated using quantitative polymerase chain reaction. CCK-8 assays were conducted to measure OS cell viability in response to miR-1-3p overexpression. Colony forming assays and EdU staining were conducted for measurement of cell proliferation, and flow cytometry analysis was performed to determine cell apoptosis and cell cycle progression. Protein levels of apoptotic markers, beta-catenin, and Wnt downstream targets were quantified using western blotting. The binding relation between miR-1-3p and cyclin dependent kinase 14 (CDK14) was validated utilizing luciferase reporter assays. Experimental results revealed that miR-1-3p expression was decreased in OS tissues and cells. Additionally, miR-1-3p inhibited cell proliferation and cell cycle progression while enhancing OS cell apoptosis. Moreover, miR-1-3p directly targeted CDK14 and inversely regulated CDK14 expression in OS cells. Furthermore, miR-1-3p inactivated the Wnt/beta-catenin signaling. CDK14 overexpression partially rescued the inhibitory impact of miR-1-3p on OS cell growth. Overall, miR-1-3p inhibits OS cell proliferation and cell cycle progression while promoting cell apoptosis by targeting CDK14 and inactivating the Wnt/beta-catenin signaling.

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.

Exploring the diversity of cancer-associated fibroblasts: insights into mechanisms of drug resistance

Introduction: Among the various stromal cell types within the tumor microenvironment, cancer-associated fibroblasts (CAFs) emerge as the predominant constituent, exhibiting a diverse array of oncogenic functions not intrinsic to normal fibroblasts. Their involvement spans across all stages of tumorigenesis, encompassing initiation, progression, and metastasis. Current understanding posits the coexistence of distinct subpopulations of CAFs within the tumor microenvironment across a spectrum of solid tumors, showcasing both pro- and antitumor activities. Recent advancements in single-cell transcriptomics have revolutionized our ability to meticulously dissect the heterogeneity inherent to CAF populations. Furthermore, accumulating evidence underscores the pivotal role of CAFs in conferring therapeutic resistance to tumors against various drug modalities. Consequently, efforts are underway to develop pharmacological agents specifically targeting CAFs. Methods: This review embarks on a comprehensive analysis, consolidating data from 36 independent single-cell RNA sequencing investigations spanning 17 distinct human malignant tumor types. Results: Our exploration centers on elucidating CAF population markers, discerning their prognostic relevance, delineating their functional contributions, and elucidating the underlying mechanisms orchestrating chemoresistance. Discussion: Finally, we deliberate on the therapeutic potential of harnessing CAFs as promising targets for intervention strategies in clinical oncology.

Deciphering chemoresistance in osteosarcoma: Unveiling regulatory mechanisms and function through the lens of noncoding RNA

Osteosarcoma (OS) is a primary malignant bone tumor and is prevalent in children, adolescents, and elderly individuals. It has the characteristics of high invasion and metastasis. Neoadjuvant chemotherapy combined with surgical resection is the most commonly used treatment for OS. However, the efficacy of OS is considerably diminished by chemotherapy resistance. In recent years, noncoding RNAs (ncRNAs), including microRNAs, long noncoding RNAs, and circular RNAs, are hot topics in the field of chemotherapy resistance research. Several studies have demonstrated that ncRNAs are substantially associated with chemoresistance in OS. Thus, the present study overviews the abnormally expressed ncRNAs in OS and the molecular mechanisms involved in chemoresistance, with an emphasis on their function in promoting or inhibiting chemoresistance. ncRNAs are expected to become potential therapeutic targets for overcoming drug resistance and predictive biomarkers in OS, which are of great significance for enhancing the therapeutic effect and improving the prognosis.

Emerging roles of long non-coding RNAs in osteosarcoma

Osteosarcoma (OS) is a highly aggressive and lethal malignant bone tumor that primarily afflicts children, adolescents, and young adults. However, the molecular mechanisms underlying OS pathogenesis remain obscure. Mounting evidence implicates dysregulated long non-coding RNAs (lncRNAs) in tumorigenesis and progression. These lncRNAs play a pivotal role in modulating gene expression at diverse epigenetic, transcriptional, and post-transcriptional levels. Uncovering the roles of aberrant lncRNAs would provide new insights into OS pathogenesis and novel tools for its early diagnosis and treatment. In this review, we summarize the significance of lncRNAs in controlling signaling pathways implicated in OS development, including the Wnt/β-catenin, PI3K/AKT/mTOR, NF-κB, Notch, Hippo, and HIF-1α. Moreover, we discuss the multifaceted contributions of lncRNAs to drug resistance in OS, as well as their potential to serve as biomarkers and therapeutic targets. This review aims to encourage further research into lncRNA field and the development of more effective therapeutic strategies for patients with OS.

Unravelling the role of immune cells and FN1 in the recurrence and therapeutic process of skull base chordoma

BACKGROUND

Skull base chordoma is a rare and aggressive tumour of the bone that has a high likelihood of recurrence. The fundamental differences in single cells between primary and recurrent lesions remain poorly understood, impeding development of effective treatment approaches.

METHODS

To obtain an understanding of the differences in single cells between primary and recurrent chordomas, we performed single-cell RNA sequencing and T-cell/B-cell receptor (BCR) sequencing. This allowed us to delineate the differences between the two types of tumour cells, tumour-infiltrating lymphocytes, myeloid cells, fibroblasts and B cells. Copy number variants (CNVs) were detected and compared between the tumour types to assess heterogeneity. Selected samples were subjected to immunohistochemistry to validate protein expression. Fluorescence in situ hybridisation experiments, Transwell assays and xenograft mouse models helped verify the role of fibronectin 1 (FN1) in chordoma.

RESULTS

Promoting natural killer (NK) cell and CD8_GZMK T-cell function or inhibiting the transformation of CD8_GZMK T cells to CD8_ZNF683 T cells and promoting the transformation of natural killer T (NKT) cells to NK cells are promising strategies for preventing chordoma recurrence. Additionally, inhibiting the M2-like activity of tumour-associated macrophages (TAMs) could be an effective approach. Antigen-presenting cancer-associated fibroblasts (apCAFs) and dendritic cells (DCs) with high enrichment of the antigen-presenting signature were enriched in primary chordomas. There were fewer plasma cells and BCR clonotypes in recurrent chordomas. Remarkably, FN1 was upregulated, had more CNVs, and was more highly secreted by tumours, macrophages, CD4 T cells, CD8 T cells and fibroblasts in recurrent chordoma than in primary chordoma. Finally, FN1 enhanced the invasion and proliferation of chordomas in vivo and in vitro.

CONCLUSION

Our comprehensive picture of the microenvironment of primary and recurrent chordomas provides deep insights into the mechanisms of chordoma recurrence. FN1 is an important target for chordoma therapy.

Insights into the involvement of long non-coding RNAs in doxorubicin resistance of cancer

Doxorubicin is one of the most classical chemotherapeutic drugs for the treatment of cancer. However, resistance to the cytotoxic effects of doxorubicin in tumor cells remains a major obstacle. Aberrant expression of long non-coding RNAs (lncRNAs) has been associated with tumorigenesis and development via regulation of chromatin remodeling, transcription, and post-transcriptional processing. Emerging studies have also revealed that dysregulation of lncRNAs mediates the development of drug resistance through multiple molecules and pathways. In this review, we focus on the role and mechanism of lncRNAs in the progress of doxorubicin resistance in various cancers, which mainly include cellular drug transport, cell cycle disorder, anti-apoptosis, epithelial-mesenchymal transition, cancer stem cells, autophagy, tumor microenvironment, metabolic reprogramming and signaling pathways. This review is aimed to provide potential therapeutic targets for future cancer therapy, especially for the reversal of chemoresistance.

Shielding and nurturing: Fibronectin as a modulator of cancer drug resistance

Resistance to chemotherapy and targeted therapies constitute a common hallmark of most cancers and represent a dominant factor fostering tumor relapse and metastasis. Fibronectin, an abundant extracellular matrix glycoprotein, has long been proposed to play an important role in the pathobiology of cancer. Recent research has unraveled the role of Fibronectin in the onset of chemoresistance against a variety of antineoplastic drugs including DNA-damaging agents, hormone receptor antagonists, tyrosine kinase inhibitors, microtubule destabilizing agents, etc. The current review summarizes the role played by Fibronectin in mediating drug resistance against diverse anticancer drugs. We have also discussed how the aberrant expression of Fibronectin drives the oncogenic signaling pathways ultimately leading to drug resistance through the inhibition of apoptosis, promotion of cancer cell growth and proliferation.

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.

Integrative Analysis and Experimental Validation of Competing Endogenous RNAs in Obstructive Sleep Apnea

Background: Obstructive sleep apnea (OSA) is highly prevalent yet underdiagnosed. This study aimed to develop a predictive signature, as well as investigate competing endogenous RNAs (ceRNAs) and their potential functions in OSA. Methods: The GSE135917, GSE38792, and GSE75097 datasets were collected from the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database. Weighted gene correlation network analysis (WGCNA) and differential expression analysis were used to identify OSA-specific mRNAs. Machine learning methods were applied to establish a prediction signature for OSA. Furthermore, several online tools were used to establish the lncRNA-mediated ceRNAs in OSA. The hub ceRNAs were screened using the cytoHubba and validated by real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Correlations between ceRNAs and the immune microenvironment of OSA were also investigated. Results: Two gene co-expression modules closely related to OSA and 30 OSA-specific mRNAs were obtained. They were significantly enriched in the antigen presentation and lipoprotein metabolic process categories. A signature that consisted of five mRNAs was established, which showed a good diagnostic performance in both independent datasets. A total of twelve lncRNA-mediated ceRNA regulatory pathways in OSA were proposed and validated, including three mRNAs, five miRNAs, and three lncRNAs. Of note, we found that upregulation of lncRNAs in ceRNAs could lead to activation of the nuclear factor kappa B (NF-κB) pathway. In addition, mRNAs in the ceRNAs were closely correlated to the increased infiltration level of effector memory of CD4 T cells and CD56bright natural killer cells in OSA. Conclusions: In conclusion, our research opens new possibilities for diagnosis of OSA. The newly discovered lncRNA-mediated ceRNA networks and their links to inflammation and immunity may provide potential research spots for future studies.

Endogenous Extracellular Matrix Regulates the Response of Osteosarcoma 3D Spheroids to Doxorubicin

The extracellular matrix (ECM) modulates cell behavior, shape, and viability as well as mechanical properties. In recent years, ECM disregulation and aberrant remodeling has gained considerable attention in cancer targeting and prevention since it may stimulate tumorigenesis and metastasis. Here, we developed an in vitro model that aims at mimicking the in vivo tumor microenvironment by recapitulating the interactions between osteosarcoma (OS) cells and ECM with respect to cancer progression. We long-term cultured 3D OS spheroids made of metastatic or non-metastatic OS cells mixed with mesenchymal stromal cells (MSCs); confirmed the deposition of ECM proteins such as Type I collagen, Type III collagen, and fibronectin by the stromal component at the interface between tumor cells and MSCs; and found that ECM secretion is inhibited by a neutralizing anti-IL-6 antibody, suggesting a new role of this cytokine in OS ECM deposition. Most importantly, we showed that the cytotoxic effect of doxorubicin is reduced by the presence of Type I collagen. We thus conclude that ECM protein deposition is crucial for modelling and studying drug response. Our results also suggest that targeting ECM proteins might improve the outcome of a subset of chemoresistant tumors.

The strategy and clinical relevance of in vitro models of MAP resistance in osteosarcoma: a systematic review

Over the last 40 years osteosarcoma (OS) survival has stagnated with patients commonly resistant to neoadjuvant MAP chemotherapy involving high dose methotrexate, adriamycin (doxorubicin) and platinum (cisplatin). Due to the rarity of OS, the generation of relevant cell models as tools for drug discovery is paramount to tackling this issue. Four literature databases were systematically searched using pre-determined search terms to identify MAP resistant OS cell lines and patients. Drug exposure strategies used to develop cell models of resistance and the impact of these on the differential expression of resistance associated genes, proteins and non-coding RNAs are reported. A comparison to clinical studies in relation to chemotherapy response, relapse and metastasis was then made. The search retrieved 1891 papers of which 52 were relevant. Commonly, cell lines were derived from Caucasian patients with epithelial or fibroblastic subtypes. The strategy for model development varied with most opting for continuous over pulsed chemotherapy exposure. A diverse resistance level was observed between models (2.2-338 fold) with 63% of models exceeding clinically reported resistance levels which may affect the expression of chemoresistance factors. In vitro p-glycoprotein overexpression is a key resistance mechanism; however, from the available literature to date this does not translate to innate resistance in patients. The selection of models with a lower fold resistance may better reflect the clinical situation. A comparison of standardised strategies in models and variants should be performed to determine their impact on resistance markers. Clinical studies are required to determine the impact of resistance markers identified in vitro in poor responders to MAP treatment, specifically with respect to innate and acquired resistance. A shift from seeking disputed and undruggable mechanisms to clinically relevant resistance mechanisms may identify key resistance markers that can be targeted for patient benefit after a 40-year wait.

The Involvement of Long Non-Coding RNAs in Glutamine-Metabolic Reprogramming and Therapeutic Resistance in Cancer

Metabolic alterations that support the supply of biosynthetic molecules necessary for rapid and sustained proliferation are characteristic of cancer. Some cancer cells rely on glutamine to maintain their energy requirements for growth. Glutamine is an important metabolite in cells because it not only links to the tricarboxylic acid cycle by producing α-ketoglutarate by glutaminase and glutamate dehydrogenase but also supplies other non-essential amino acids, fatty acids, and components of nucleotide synthesis. Altered glutamine metabolism is associated with cancer cell survival, proliferation, metastasis, and aggression. Furthermore, altered glutamine metabolism is known to be involved in therapeutic resistance. In recent studies, lncRNAs were shown to act on amino acid transporters and glutamine-metabolic enzymes, resulting in the regulation of glutamine metabolism. The lncRNAs involved in the expression of the transporters include the abhydrolase domain containing 11 antisense RNA 1, LINC00857, plasmacytoma variant translocation 1, Myc-induced long non-coding RNA, and opa interacting protein 5 antisense RNA 1, all of which play oncogenic roles. When it comes to the regulation of glutamine-metabolic enzymes, several lncRNAs, including nuclear paraspeckle assembly transcript 1, XLOC_006390, urothelial cancer associated 1, and thymopoietin antisense RNA 1, show oncogenic activities, and others such as antisense lncRNA of glutaminase, lincRNA-p21, and ataxin 8 opposite strand serve as tumor suppressors. In addition, glutamine-dependent cancer cells with lncRNA dysregulation promote cell survival, proliferation, and metastasis by increasing chemo- and radio-resistance. Therefore, understanding the roles of lncRNAs in glutamine metabolism will be helpful for the establishment of therapeutic strategies for glutamine-dependent cancer patients.

Identification of Common Oncogenic Genes and Pathways Both in Osteosarcoma and Ewing’s Sarcoma Using Bioinformatics Analysis

This study was aimed at exploring common oncogenic genes and pathways both in osteosarcoma and Ewing's sarcoma. Microarray data were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified using the limma package. Then, protein-protein interaction (PPI) networks were constructed and hub genes were identified. Furthermore, functional enrichment analysis was analyzed. The expression of common oncogenic genes was validated in 38 osteosarcoma and 17 Ewing's sarcoma tissues by RT-qPCR and western blot compared to normal tissues. 201 genes were differentially expressed. There were 121 nodes and 232 edges of the PPI network. Among 12 hub genes, hub genes FN1, COL1A1, and COL1A2 may involve in the development of osteosarcoma and Ewing's sarcoma. And they were reduced to expression both in osteosarcoma and Ewing's sarcoma tissues at mRNA and protein levels compared to normal tissues. Knockdown of FN1, COL1A1, and COL1A2 enhanced the cell proliferation and migration of U2OS under the restriction of cisplatin. Our findings revealed the common oncogenic genes such as FN1, COL1A1, and COL1A2, which may act as antioncogene by enhancing cisplatin sensitivity in osteosarcoma cells, and pathways were both in osteosarcoma and Ewing's sarcoma.

Regulatory functions of miR‑200b‑3p in tumor development (Review)

MicroRNAs (miRNAs/miRs), non‑coding single‑stranded RNAs of length 18‑24 nucleotides, can modulate gene expression through post‑transcriptional control. As such, they can influence tumor proliferation, apoptosis, invasion, metastasis as well as chemotherapy resistance by regulating certain downstream genes. In this context, miR‑200b‑3p, one particular member of the miR‑200 family, possesses the ability to suppress tumor progression. However, many studies have suggested that, in certain cases, this miRNA may also promote the development of some tumors due to differences in the microenvironments and molecular backgrounds of different cancers. This review summarizes previous studies on the involvement of miR‑200b‑3p in tumors, including the underlying mechanism.

The role of lncRNA OIP5-AS1 in cancer development and progression

OIP5-AS1, a conserved lncRNA, has been reported to be involved in several biological and pathological processes, including oncogenesis. OIP5-AS1 exerts its oncogenic or antitumor functions via regulation of different miRNAs in various cancer types. In this review, we describe the dysregulation of OIP5-AS1 expression in a variety of human cancers. Moreover, we discuss the multiple functions of OIP5-AS1 in cancer, including in proliferation, apoptosis, autophagy, ferroptosis, cell cycle, migration, metastasis, invasion, epithelial to mesenchymal transition, angiogenesis, cancer stem cells and drug resistance. Furthermore, we provide a future perspective for OIP5-AS1 research. We conclude that targeting OIP5-AS1 might be a promising cancer therapy approach.

Butorphanol Suppresses the Proliferation and Migration of Osteosarcoma by Promoting the Expression of piRNA hsa_piR_006613

Butorphanol, a partial agonist of opioid receptor κ 1 receptor, can and is widely used as an analgesic drug to relieve moderate and severe pain in clinic. Osteosarcoma is one of the most common malignant bone tumor in adolescents under the age of 20. To our knowledge no study has investigated the effect of butorphanol on the proliferation of osteosarcoma cells. In this study, The proliferation of osteosarcoma cells was measured by CCK-8 and colony formation assays, and the migration of osteosarcoma cells were detected by scratch and transwell assays. The expression of piRNA was detected by RNA sequencing and real-time PCR. PiRNA mimics or inhibitors have been used to upregulate or inhibit piRNA expression in osteosarcoma cells, respectively. We found that butorphanol, at the concentration of 10ug/ml or higher, could significantly inhibit the proliferation and migration of osteosarcoma cells. Our resuslts indicated that butorphanol promoted the expression of piRNA hsa_piR_006613 and overexpression of piRNA hsa_piR_006613 inhibited the proliferation and migration of osteosarcoma cells. our study also showed that inhibition of the expression of piRNA hsa_piR_006613 could promote the proliferation and migration of osteosarcoma cells. Butorphanol played the regulatory role on osteosarcoma cells in dependent of piRNA hsa_piR_006613. Butorphanol was found to inhibit the proliferation and migration of osteosarcoma cells by promoting piRNA hsa_piR_006613 expression. Bioinformatics analysis showed that hsa_piR_006613 downregulated FN1 protein expression by binding with 3’-UTR of FN1 mRNA. In all, the present research indicated that butorphanol suppresses the proliferation of osteosarcoma by promoting the expression of piRNA hsa_piR_006613, which downregulated the expression of FN1. Has_piR_006613 may become a new therapeutic target for osteosarcoma.

LncRNA Opa interacting protein 5-antisense RNA 1 (OIP5-AS1) promotes the migration, invasion and epithelial-mesenchymal transition (EMT) through targeting miR-147a/insulin-like growth factor 1 receptor (IGF1R) pathway in cervical cancer tissues and cell model

BACKGROUND

Two factors involved in regulation, long noncoding RNA Opa interacting protein 5-antisense RNA 1 (lncRNA OIP5-AS1) and microRNA-147a, were found in cervical cancer. Therefore, the investigation of the specific regulation of miR-147a by OIP5-AS1 was performed in cervical cancer.

METHOD

The cervical cancer tissues were collected from patients with cervical cancer (n = 50). The expression of OIP5-AS1, miR-147a, proteins in epithelial-mesenchymal transition (EMT) process and insulin-like growth factor 1 receptor (IGF1R) were measured by quantitative real-time polymerase chain reaction (qRT-PCT) or western blotting. Cell motility and the relationship between OIP5-AS1 and miR-147a were detected or analyzed by wound healing test, Transwell assay, dual-luciferase reporter assay, RNA binding protein immunoprecipitation assay or Pearson correlation in OIP5-AS1, or miR-147a over-expressed and/or suppressed cervical cancer cells.

RESULTS

OIP5-AS1 showed the high-expression and miR-147a showed the low-expression in tumor tissues collected from patients with cervical cancer and cell lines Hela, CaSki, Siha, and ME-180. The low-expression of OIP5-AS1 suppressed the motility of Caski cells, as well as up-regulated the level of E-cadherin, which a key protein in EMT. There were targeting sites between miR-147a and OIP5-AS1. OIP5-AS1 induced the down-regulation of miR-147a, so miR-147a was inversely correlated with OIP5-AS1. The down-regulation of miR-147a increased IGF1R and E-cadherin, and these increases were alleviated by OIP5-AS1 knockdown.

CONCLUSION

LncRNA OIP5-AS1 promotes the migration, invasion and EMT of cervical cancer cells via targeting miR-147a/IGF1R pathway.

Long non-coding RNA OIP5-AS1 (Cyrano): A context-specific regulator of normal and disease processes

Long non-coding (lnc) RNAs have been implicated in a plethora of normal biological functions, and have also emerged as key molecules in various disease processes. OIP5-AS1, also commonly known by the alias Cyrano, is a lncRNA that displays broad expression across multiple tissues, with significant enrichment in particular contexts including within the nervous system and skeletal muscle. Thus far, this multifaceted lncRNA has been found to have regulatory functions in normal cellular processes including cell proliferation and survival, as well as in the development and progression of a myriad disease states. These widespread effects on normal and disease states have been found to be mediated through context-specific intermolecular interactions with dozens of miRNAs and proteins identified to date. This review explores recent studies to highlight OIP5-AS1's contextual yet pleiotropic roles in normal homeostatic functions as well as disease oetiology and progression, which may influence its utility in the generation of future theranostics.

Metastatic EMT Phenotype Is Governed by MicroRNA-200-Mediated Competing Endogenous RNA Networks

Epithelial–mesenchymal transition (EMT) is a fundamental physiologically relevant process that occurs during morphogenesis and organ development. In a pathological setting, the transition from epithelial toward mesenchymal cell phenotype is hijacked by cancer cells, allowing uncontrolled metastatic dissemination. The competing endogenous RNA (ceRNA) hypothesis proposes a competitive environment resembling a large-scale regulatory network of gene expression circuits where alterations in the expression of both protein-coding and non-coding genes can make relevant contributions to EMT progression in cancer. The complex regulatory diversity is exerted through an array of diverse epigenetic factors, reaching beyond the transcriptional control that was previously thought to single-handedly govern metastatic dissemination. The present review aims to unravel the competitive relationships between naturally occurring ceRNA transcripts for the shared pool of the miRNA-200 family, which play a pivotal role in EMT related to cancer dissemination. Upon acquiring more knowledge and clinical evidence on non-genetic factors affecting neoplasia, modulation of the expression levels of diverse ceRNAs may allow for the development of novel prognostic/diagnostic markers and reveal potential targets for the disruption of cancer-related EMT.

The P2RX7B splice variant modulates osteosarcoma cell behaviour and metastatic properties

•

P2RX7B expression confers a survival advantage in TE85+P2RX7B and MNNG-HOS+P2RX7B OS cell lines.

•

P2RX7B expression reduced cell adhesion and activation promoted invasion and migration in vitro.

•

MNNG-HOS+P2RX7B tumours in vivo exhibited ectopic bone formation that A740003 reduced.

•

Expression of P2RX7B in primary tumour cells increased the propensity to metastasise to the lungs.

•

A novel gene axis, FN1/LOX/PDGFB/IGFBP3/BMP4 was downregulated in response to A740003.

Background

Osteosarcoma (OS) is the most common type of primary bone cancer affecting children and adolescents. OS has a high propensity to spread meaning the disease is often incurable and fatal. There have been no improvements in survival rates for decades. This highlights an urgent need for the development of novel therapeutic strategies. Here, we report in vitro and in vivo data that demonstrates the role of purinergic signalling, specifically, the B isoform of the purinergic receptor P2RX7 (P2RX7B), in OS progression and metastasis.

Methods

TE85 and MNNG-HOS OS cells were transfected with P2RX7B. These cell lines were then characterised and assessed for proliferation, cell adhesion, migration and invasion in vitro. We used these cells to perform both paratibial and tail vein injected mouse studies where the primary tumour, bone and lungs were analysed. We used RNA-seq to identify responsive pathways relating to P2RX7B.

Results

Our data shows that P2RX7B expression confers a survival advantage in TE85 + P2RX7B and MNNG-HOS + P2RX7B human OS cell lines in vitro that is minimised following treatment with A740003, a specific P2RX7 antagonist. P2RX7B expression reduced cell adhesion and P2RX7B activation promoted invasion and migration in vitro, demonstrating a metastatic phenotype. Using an in vivo OS xenograft model, MNNG-HOS + P2RX7B tumours exhibited cancer-associated ectopic bone formation that was abrogated with A740003 treatment. A pro-metastatic phenotype was further demonstrated in vivo as expression of P2RX7B in primary tumour cells increased the propensity of tumour cells to metastasise to the lungs. RNA-seq identified a novel gene axis, FN1/LOX/PDGFB/IGFBP3/BMP4, downregulated in response to A740003 treatment.

Conclusion

Our data illustrates a role for P2RX7B in OS tumour growth, progression and metastasis. We show that P2RX7B is a future therapeutic target in human OS.

LncRNA OIP5-AS1 Promotes the Autophagy-Related Imatinib Resistance in Chronic Myeloid Leukemia Cells by Regulating miR-30e-5p/ATG12 Axis

Background: Resistance to tyrosine kinase inhibitors (TKIs) in patients with chronic myeloid leukemia (CML) remains a problem in clinical treatment, and the mechanism has not been fully clarified. Autophagy can protect cancer cells under chemotherapeutic stimulation. Long noncoding RNAs (lncRNAs) are critical in drug resistance of CML. The role of lncRNAs in autophagy and drug resistance of CML needs to be further explored. Methods: Western blot and immunofluorescence were used to evaluate the autophagy activity in the drug-resistant CML cell line K562/G01 and its parental cell line K562. Then the sensitivity of K562/G01 cells to the first generation TKI imatinib (IM) after autophagy inhibition was determined by CCK-8 assays. The lncRNA OIP5-AS1 related to the drug resistance of CML cells was determined by Gene Expression Omnibus database analysis. Western blot and drug-sensitivity assays were used to detect changes in autophagy and sensitivity to the IM in resistant CML cells after OIP5-AS1 knockdown. The interactions of OIP5-AS1, miR-30e-5p, and ATG12 were explored by RNA immunoprecipitation and dual-luciferase reporter assays. Results: In this study, we found that autophagy was associated with drug resistance in CML cells. Moreover, the upregulation of OIP5-AS1 in K562/G01 cells was related to the enhancement of autophagy. Knockdown of OIP5-AS1 suppressed autophagy and enhanced the sensitivity of K562/G01 cells to IM. Furthermore, OIP5-AS1 regulated ATG12 by competitively binding miR-30e-5p, thereby affecting autophagy-related drug resistance. Conclusion: Our study reveals that OIP5-AS1 promotes the autophagy-related IM resistance in CML cells by regulating miR-30e-5p/ATG12 axis, providing new insights into the drug resistance mechanism of CML.

The Integrative Analysis of Competitive Endogenous RNA Regulatory Networks in Coronary Artery Disease

Background: Coronary artery disease (CAD) is the leading cause of cardiovascular death. The competitive endogenous RNAs (ceRNAs) hypothesis is a new theory that explains the relationship between lncRNAs and miRNAs. The mechanism of ceRNAs in the pathological process of CAD has not been fully elucidated. The objective of this study was to explore the ceRNA mechanism in CAD using the integrative bioinformatics analysis and provide new research ideas for the occurrence and development of CAD.

Methods: The GSE113079 dataset was downloaded, and differentially expressed lncRNAs (DElncRNAs) and genes (DEGs) were identified using the limma package in the R language. Weighted gene correlation network analysis (WGCNA) was performed on DElncRNAs and DEGs to explore lncRNAs and genes associated with CAD. Functional enrichment analysis was performed on hub genes in the significant module identified via WGCNA. Four online databases, including TargetScan, miRDB, miRTarBase, and Starbase, combined with an online tool, miRWalk, were used to construct ceRNA regulatory networks.

Results: DEGs were clustered into ten co-expression modules with different colors using WGCNA. The brown module was identified as the key module with the highest correlation coefficient. 188 hub genes were identified in the brown module for functional enrichment analysis. DElncRNAs were clustered into sixteen modules, including seven modules related to CAD with the correlation coefficient more than 0.5. Three ceRNA networks were identified, including OIP5-AS1-miR-204-5p/miR-211-5p-SMOC1, OIP5-AS1-miR-92b-3p-DKK3, and OIP5-AS1-miR-25-3p-TMEM184B.

Conclusion: Three ceRNA regulatory networks identified in this study may play crucial roles in the occurrence and development of CAD, which provide novel insights into the ceRNA mechanism in CAD.

Long non-coding RNAs as the critical regulators of doxorubicin resistance in tumor cells

Resistance against conventional chemotherapeutic agents is one of the main reasons for tumor relapse and poor clinical outcomes in cancer patients. Various mechanisms are associated with drug resistance, including drug efflux, cell cycle, DNA repair and apoptosis. Doxorubicin (DOX) is a widely used first-line anti-cancer drug that functions as a DNA topoisomerase II inhibitor. However, DOX resistance has emerged as a large hurdle in efficient tumor therapy. Furthermore, despite its wide clinical application, DOX is a double-edged sword: it can damage normal tissues and affect the quality of patients’ lives during and after treatment. It is essential to clarify the molecular basis of DOX resistance to support the development of novel therapeutic modalities with fewer and/or lower-impact side effects in cancer patients. Long non-coding RNAs (lncRNAs) have critical roles in the drug resistance of various tumors. In this review, we summarize the state of knowledge on all the lncRNAs associated with DOX resistance. The majority are involved in promoting DOX resistance. This review paves the way to introducing an lncRNA panel marker for the prediction of the DOX response and clinical outcomes for cancer patients.

Down-regulation of circITCH promotes osteosarcoma development and resistance to doxorubicin via the miR-524/RASSF6 axis

BACKGROUND

Osteosarcoma (OS) is a malignant bone cancer, in which circular RNAs (circRNAs) act as important modulators. The present study aimed to explore the functional role of circRNA itchy E3 ubiquitin protein ligase (circITCH) in the development and doxorubicin (DXR) resistance of OS and the possible mechanistic pathway.

METHODS

A quantitative real-time polymerase chain reaction or western blot assays were exploited to analyze the expression of circITCH, miR-524 and Ras association domain family member 6 (RASSF6). Cell viability and half-maximal inhibitory concentration (IC₅₀ ) value of DXR were monitored using a cell counting kit-8 assay. Cell migration, invasion and apoptosis were determined via a transwell assay and flow cytometry. The target interaction among circITCH, miR-524 and RASSF6 was validated by dual-luciferase reporter and RNA immunoprecipitation assays. A xenograft model of MG-63/DXR cells stably expressing circITCH in nude mice was established for assessing the role of circITCH in vivo.

RESULTS

Down-regulation of circITCH and RASSF6, as well as the up-regulation of miR-524, was revealed in OS by investigating 40 paired OS tissue and normal tissue samples. Overexpression of circITCH lowered the cell viability, IC₅₀ value of DXR, migration and invasion, whereas it facilitated apoptosis of OS cells. circITCH sponged miR-524 to up-regulate RASSF6, causing OS progression inhibition and DXR resistance reduction. Additionally, circITCH up-regulation reduced tumor growth in vivo.

CONCLUSIONS

Transduction with circITCH represses OS progression and promotes DXR sensitivity by the miR-524/RASSF6 axis, providing a new perspective for therapeutic intervention.

Emerging Role of MicroRNA-200 Family in Dentistry

MicroRNAs (miRNAs) are endogenous non-coding RNAs ~22 nucleotides in length, which have been shown to participate in various biological processes. As one of the most researched miRNAs, the miR-200 family has been found to regulate several factors that are associated with the epithelial to mesenchymal transition (EMT) and cancer stem cells (CSCs) behavior. In this review, we briefly summarize the background of the miR-200 family and their implication in various dental diseases. We focus on the expression changes, biological functions, and clinical significance of the miR-200 family in oral cancer; periodontitis; oral potentially malignant disorder; gingival overgrowth; and other periodontal diseases. Additionally, we discuss the use of the miR-200 family as molecular biomarkers for diagnosis, prognostic, and therapeutic application.

The role of miRNAs and lncRNAs in conferring resistance to doxorubicin

Doxorubicin is a chemotherapeutic agent that inhibits topoisomerase II, intercalates within DNA base pairs and results in oxidative DNA damage, thus inducing cell apoptosis. Although it is effective in the treatment of a wide range of human cancers, the emergence of resistance to this drug can increase tumour growth and impact patients' survival. Numerous molecular mechanisms and signalling pathways have been identified that induce resistance to doxorubicin via stimulation of cell proliferation, cell cycle switch and preclusion of apoptosis. A number of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) have also been identified that alter sensitivity to doxorubicin. Understanding the particular impact of these non-coding RNAs in conferring resistance to doxorubicin has considerable potential to improve selection of chemotherapeutic regimens for cancer patients. Moreover, modulation of expression of these transcripts is a putative strategy for combating resistance. In the current paper, the influence of miRNAs and lncRNAs in the modification of resistance to doxorubicin is discussed.

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.

A review on the role of oncogenic lncRNA OIP5-AS1 in human malignancies

OIP5-AS1 is a long non-coding transcript with high expression in nervous system, but crucial functions in the neoplastic transformation. This lncRNA partake in the regulation of cell cycle transition at different points. Moreover, it acts a competing endogenous RNA for tens of microRNAs among them are miR-338-3p, miR-204-5p, miR-641, miR-422a, miR-367-3p, miR-153-3p, miR-186, miR-369-3p, miR-137, miR-342-3p, miR‑429, miR-3163, miR-363-3p, miR-186a-5p, hsa-miR-26a-3p, miR‑300, miR-217, miR-378a-3p and miR-448. OIP5-AS1 influence the carcinogenesis via different routes among them is modulation of epithelial-mesenchymal transition. Expression of OIP5-AS1 has been elevated in nearly all kinds of neoplastic tissues except for multiple myeloma. Moreover, in bladder, gastric cancer and lung cancers, assessment of its expression in clinical samples has led to conflicting results. In the current paper, we have provided a comprehensive collection of research papers that evaluated function of OIP5-AS1 in diverse cancer types.

Noncoding RNAs in osteosarcoma: Implications for drug resistance

Osteosarcoma is the most frequent bone malignancy in children and adolescents. Despite advances of surgery and chemotherapy in osteosarcoma over the past decades, overall survival rates of osteosarcoma have reached a plateau. The development of multi-drug resistance (MDR) has become the main obstacle in improving chemotherapeutic effects in osteosarcoma treatment. Therefore, understanding detailed mechanisms of chemoresistance and developing novel therapeutic targets to overcome chemoresistance are crucial to improve the prognosis of osteosarcoma patients. Accumulating evidence has proved that multiple noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) play pivotal roles in osteosarcoma progression. Notably, a great number of ncRNAs are abnormally expressed and can regulate chemosensitivity through various mechanisms in osteosarcoma. In this review, we systematically summarize the roles of ncRNAs as well as the molecular mechanisms in modulating drug resistance of osteosarcoma and discuss the potential roles of ncRNAs as biomarkers and novel therapeutic targets for osteosarcoma.

Recent Insights into Therapy Resistance in Osteosarcoma

Osteosarcoma, the most common bone malignancy of childhood, has been a challenge to treat and cure. Standard chemotherapy regimens work well for many patients, but there remain minimal options for patients with progressive or resistant disease, as clinical trials over recent decades have failed to significantly improve survival. A better understanding of therapy resistance is necessary to improve current treatments and design new strategies for future treatment options. In this review, we discuss known mechanisms and recent scientific advancements regarding osteosarcoma and its patterns of resistance against chemotherapy, radiation, and other newly-introduced therapeutics.

Expression of Extracellular Matrix-Related Genes and Their Regulatory microRNAs in Problematic Colorectal Polyps

Colorectal carcinoma usually evolves gradually, forming a spectrum of lesions, due to accumulation of genetic mutations and epigenetic alterations. Many early lesions are detected since the introduction of screening programs. The greatest challenge is to distinguish between adenomas with epithelial misplacement (AEM) and adenomas with early carcinoma (AEC), considering the diagnosis affects prognosis and treatment. We analyzed the expression of selected extracellular matrix (ECM)-related genes and proteins, and their regulatory microRNAs using RT-qPCR and immunohistochemistry in biopsies from 44 patients. Differences were observed in AEM in comparison to AEC for DCN, EPHA4, FN1, SPON2, and SPP1, reflecting inflammatory stromal reaction to traumatisation and misplacement of dysplastic glands in the submucosa in the former, and desmoplastic stromal reaction to true invasion of dysplastic glands in the submucosa in the latter. Expression of regulatory microRNAs hsa-miR-200c and hsa-miR-146a significantly negatively correlated with the expression of their regulated genes, while significant difference between AEM and AEC was observed only for hsa-miR-29c. The described expression patterns are too complex to be used in diagnostic work, but might contribute to better understanding ECM changes in colorectal carcinoma development, helping to find new markers in the future.

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.

Prognostic and clinicopathologic significance of long non-coding RNA opa-interacting protein 5-antisense RNA 1 in multiple human cancers

Background: OIP5-AS1 has been reported to be aberrantly expressed in multiple cancers and associated with clinical outcomes. We conducted this study to assess the generalized prognostic value of OIP5-AS1 in cancers.Methods: PubMed, Web of science, and Cochrane Library were searched for eligible studies. Hazards ratios (HRs) or odd ratios (ORs) with 95% confidence intervals (CIs) were pooled to estimate the prognostic value of OIP5-AS1 in cancers, including overall survival (OS), age, gender, tumor size, clinical stage, and lymph node metastasis (LNM). Publication bias was measured by Begg's test and funnel plot. Sensitivity analysis were used to detect the stability of pooled results.Results: Overall, eleven studies containing 713 patients were eventually enrolled. The pooled results showed that high OIP5-AS1 expression was correlated with shorter OS (HR = 0.48, 95%CI: 0.35-0.64), regardless of the sample size, tumor type and follow-up time. Furthermore, elevated expression of OIP5-AS1 indicated advanced clinical stage (OR = 2.12, 95% CI: 1.06-4.23), but not associated with age, gender, tumor size and LNM. No publication bias was detected.Conclusion: High expression of lncRNA OIP5-AS1 may predict a poor OS and advanced clinical stage, implicating that OIP5-AS1 may be a possible prognostic factor in cancers.

The role of extracelluar matrix in osteosarcoma progression and metastasis

Osteosarcoma (OS) is the most common primary bone malignancy and responsible for considerable morbidity and mortality due to its high rates of pulmonary metastasis. Although neoadjuvant chemotherapy has improved 5-year survival rates for patients with localized OS from 20% to over 65%, outcomes for those with metastasis remain dismal. In addition, therapeutic regimens have not significantly improved patient outcomes over the past four decades, and metastases remains a primary cause of death and obstacle in curative therapy. These limitations in care have given rise to numerous works focused on mechanisms and novel targets of OS pathogenesis, including tumor niche factors. OS is notable for its hallmark production of rich extracellular matrix (ECM) of osteoid that goes beyond simple physiological growth support. The aberrant signaling and structural components of the ECM are rich promoters of OS development, and very recent works have shown the specific pathogenic phenotypes induced by these macromolecules. Here we summarize the current developments outlining how the ECM contributes to OS progression and metastasis with supporting mechanisms. We also illustrate the potential of tumorigenic ECM elements as prognostic biomarkers and therapeutic targets in the evolving clinical management of OS.

Long non-coding RNA LINC00426 contributes to doxorubicin resistance by sponging miR-4319 in osteosarcoma

Background

LINC00426 is a newly identified long non-coding RNA (lncRNA) with unacknowledged biological roles. Here we set out to characterize the expression status of LINC00426 in osteosarcoma and understand its mechanistic involvement in incidence of doxorubicin (Dox) resistance.

Methods

The relative expression of LINC00426 and miR-4319 was determined by real-time PCR. Cell viability and proliferation in response to LINC00426 silencing or miR-4319 over-expression was measured with CCK-8 kit and colony formation assay, respectively. The direct association between LINC00426 and miR-4319 was analyzed by pulldown assay with biotin-labelled probes.

Results

LINC00426 was significantly up-regulated in Dox-resistant osteosarcoma (OS) both in vitro and in vivo, which intimately associated with unfavorable prognosis. SiRNA-mediated knockdown of LINC00426 remarkably compromised cell viability and proliferation in Dox-resistant OS cells, which accompanied with decrease of IC50 and activation of caspase-3. We further predicted and validated the regulatory effects of miR-4319 on LINC00426 expression. Simultaneously, we provided evidences in support of direct binding between LINC00426 and miR-4319 by pulldown assay. Reciprocally negative regulation was observed between LINC00426 and miR-4319 each other.

Conclusion

Ectopic introduction of miR-4319 significantly surmounted the Dox resistance in OS cells, while miR-4319 inhibition in LINC00426-deficient cells greatly restore this phenotype. We uncovered the important contribution of LINC00426/miR-4319 to Dox resistance in osteosarcoma.

Reviewers

This article was reviewed by Bo Liang and Sinan Zhu.

Long noncoding RNA OIP5-AS1 mediates resistance to doxorubicin by regulating miR-137-3p/PTN axis in osteosarcoma

Opa-interacting protein 5 antisense RNA1 (OIP5-AS1) has been demonstrated to facilitate proliferation, metastasis and resistance to treatments in various types of cancers. Nevertheless, the exact mechanisms underlying the roles of OIP5-AS1 in osteosarcoma(OS) drug resistance have not yet been clearly elucidated. Therefore, we sought to investigate the functional involvement of OIP5-AS1 in osteosarcoma. Our results indicated that OIP5-AS1 was dramatically up-regulated in osteosarcoma drug-resistant tissues and cells in comparison with drug-sensitive tissues and cells. Also, the knockdown of OIP5-AS1 was found to have decreased doxorubicin resistance of OS cells. Further analyses revealed that OIP5-AS1 operated as a competitor for endogenous RNA of miR-137-3p as well as regulated pleiotrophin(PTN) expression, which has been reported to be an oncogene in OS in previous research. Furthermore, the loss of miR-137-3p or alternatively, the gain of PTN, both resulted in the abolishment of the inhibitory role of OIP5-AS1 silencing the proliferative activity. Our analyses indicated and helped to determine the role of OIP5-AS1 in contributing to tumorigenesis of osteosarcoma via the miR-137-3p/PTN axis and, therefore outlining its potential for use as a therapeutic target against this cancer.

Long Non-Coding RNA OIP5-AS1 Knockdown Enhances CDDP Sensitivity in Osteosarcoma via miR-377-3p/FOSL2 Axis

Background

Drug resistance is one of big obstacles for the treatment of tumor. Long non-coding RNA Opa-interacting protein 5-antisense RNA 1 (OIP5-AS1) was identified to involve in drug resistance. In this research, the effects of OIP5-AS1 on cisplatin (CDDP) resistance in osteosarcoma (OS) were mainly investigated.

Methods

The levels of OIP5-AS1, microRNA-377-3p (miR-377-3p), and FOS like 2 (FOSL2) were measured by quantitative real-time polymerase chain reaction. The inhibitory concentration 50 (IC₅₀) value of CDDP, cell viability and apoptotic rate was evaluated through Cell Counting Kit-8 and flow cytometry assays, respectively. The levels of multidrug resistance-associated protein 1 (MRP1), P-glycoprotein, B-cell lymphoma 2, Bcl2-associated X, cleaved-caspase-3, and FOSL2 were detected by Western blot assay. The interaction between miR-377-3p and OIP5-AS1 or FOSL2 was verified by Dual-Luciferase Reporter and RNA Immunoprecipitation assays. The function of OIP5-AS1 was detected by a xenograft tumor model in vivo.

Results

OIP5-AS1 and FOSL2 were up-regulated, while miR-377-3p was down-regulated in CDDP-resistant OS tissues and cells. OIP5-AS1 silencing inhibited cell viability and the IC₅₀ value of CDDP, and promoted apoptotic rate in CDDP-resistant OS cells. Mechanically, OIP5-AS1 was verified as a sponge to miR-377-3p and FOSL2 was a target of miR-377-3p. Moreover, OIP5-AS1 knockdown repressed OS tumor growth and enhanced CDDP sensitivity of OS in vivo.

Conclusion

OIP5-AS1 positively modulated FOSL2 expression to decrease CDDP sensitivity in OS by sponging miR-377-3p.

Identification of potential key genes in gastric cancer using bioinformatics analysis

Gastric cancer (GC) is one of the most common types of cancer worldwide. Patients must be identified at an early stage of tumor progression for treatment to be effective. The aim of the present study was to identify potential biomarkers with diagnostic value in patients with GC. To examine potential therapeutic targets for GC, four Gene Expression Omnibus (GEO) datasets were downloaded and screened for differentially expressed genes (DEGs). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were subsequently performed to study the function and pathway enrichment of the identified DEGs. A protein-protein interaction (PPI) network was constructed. The CytoHubba plugin of Cytoscape was used to calculate the degree of connectivity of proteins in the PPI network, and the two genes with the highest degree of connectivity were selected for further analysis. Additionally, the two DEGs with the largest and smallest log Fold Change values were selected. These six key genes were further examined using Oncomine and the Kaplan-Meier plotter platform. A total of 99 upregulated and 172 downregulated genes common to all four GEO datasets were screened. The DEGs were primarily enriched in the Biological Process terms: ‘extracellular matrix organization’, ‘collagen catabolic process’ and ‘cell adhesion’. These three KEGG pathways were significantly enriched in the categories: ‘ECM-receptor interaction’, ‘protein digestion and absorption’, and ‘focal adhesion’. Based on Oncomine, expression of ATP4A and ATP4B were downregulated in GC, whereas expression of the other genes were all upregulated. The Kaplan-Meier plotter platform confirmed that upregulated expression of the identified key genes was significantly associated with worse overall survival of patients with GC. The results of the present study suggest that FN1, COL1A1, INHBA and CST1 may be potential biomarkers and therapeutic targets for GC. Additional studies are required to explore the potential value of ATP4A and ATP4B in the treatment of GC.

Proteomic profiling and identification of significant markers from high-grade osteosarcoma after cryotherapy and irradiation

Biological reconstruction of allografts and recycled autografts have been widely implemented in high-grade osteogenic sarcoma. For treating tumor-bearing autografts, extracorporeal irradiation (ECIR) and liquid nitrogen (LN) freezing techniques are being used worldwide as a gold standard treatment procedure. Both the methods aim to eradicate the tumor cells from the local recurrence and restore the limb function. Therefore, it is essential and crucial to find, and compare the alterations at molecular and physiological levels of the treated and untreated OGS recycled autografts to obtain valuable clinical information for better clinical practice. Thus, we aimed to investigate the significantly expressed altered proteins from ECIR-and cryotherapy/freezing- treated OGS (n = 12) were compared to untreated OGS (n = 12) samples using LC-ESI-MS/MS analysis, and the selected proteins from this protein panel were verified using immunoblot analysis. From our comparative proteomic analysis identified a total of 131 differentially expressed proteins (DEPs) from OGS. Among these, 91 proteins were up-regulated (2.5 to 3.5-folds), and 40 proteins were down-regulated (0.2 to 0.5 folds) (p < 0.01 and 0.05). The functional enrichment analysis revealed that the identified DEPs have belonged to more than 10 different protein categories include cytoskeletal, extracellular matrix, immune, enzyme modulators, and cell signaling molecules. Among these, we have confirmed two potential candidates’ expressions levels such as Fibronectin and Protein S100 A4 using western blot analysis. Our proteomic study revealed that LN-freezing and ECIR treatments are effectively eradicating tumor cells, and reducing the higher expressions of DEPs at molecular levels which may help in restoring the limb functions of OGS autografts effectively. To the best of our knowledge, this is the first proteomic study that compared proteomic profiles among freezing, ECIR treated with untreated OGS in recycled autografts. Moreover, the verified proteins could be used as prognostic or diagnostic markers that reveal valuable scientific information which may open various therapeutic avenues in clinical practice to improve patient outcomes.

Fibronectin in Cancer: Friend or Foe

The role of fibronectin (FN) in tumorigenesis and malignant progression has been highly controversial. Cancerous FN plays a tumor-suppressive role, whereas it is pro-metastatic and associated with poor prognosis. Interestingly, FN matrix deposited in the tumor microenvironments (TMEs) promotes tumor progression but is paradoxically related to a better prognosis. Here, we justify how FN impacts tumor transformation and subsequently metastatic progression. Next, we try to reconcile and rationalize the seemingly conflicting roles of FN in cancer and TMEs. Finally, we propose future perspectives for potential FN-based therapeutic strategies.

Combining laser microdissection and microRNA expression profiling to unmask microRNA signatures in complex tissues

Neglecting tissue heterogeneity during the analysis of microRNA (miRNA) levels results in average signals from an unknown mixture of different cell types that are difficult to interpret. Here we demonstrate the technical requirements needed to obtain high-quality, quantitative miRNA expression information from tumor tissue compartments obtained by laser microdissection (LMD). Furthermore, we show the significance of disentangling tumor tissue heterogeneity by applying the newly developed protocols for combining LMD of tumor tissue compartments with RT-qPCR analysis to reveal compartment-specific miRNA expression signatures. An important advantage of this strategy is that the miRNA signature can be directly linked to histopathology. In summary, combining LMD and RT-qPCR is a powerful approach for spatial miRNA expression analysis in complex tissues, enabling discovery of disease mechanisms, biomarkers and drug candidates.

Long noncoding RNA lnc-ABCA12-3 promotes cell migration, invasion, and proliferation by regulating fibronectin 1 in esophageal squamous cell carcinoma

Long noncoding RNAs (lncRNAs) have been shown to play important roles in human cancers, including esophageal squamous cell carcinoma (ESCC). We previously demonstrated that a novel lncRNA, lnc-ABCA12-3, was overexpressed in ESCC tissues. However, the exact function of lnc-ABCA12-3 is unknown. In the current study, we aimed to evaluate the expression of lnc-ABCA12-3 in ESCC and to explore the potential mechanism of lnc-ABCA12-3 in cell migration, invasion, and proliferation. We showed that lnc-ABCA12-3 was upregulated in ESCC tumor tissues and cell lines. The increased expression of lnc-ABCA12-3 was positively associated with advanced tumor-node-metastasis stages and poor prognosis. The knockdown of lnc-ABCA12-3 inhibited the cell migration, invasion, and proliferation abilities of KYSE-510 and Eca-109 cells. We also found that fibronectin 1 (FN1) was upregulated in ESCC tumor tissues. The expression of FN1 messenger RNA was positively correlated with the expression of lnc-ABCA12-3 in ESCC tumor tissues. After lnc-ABCA12-3 knockdown, the expression of FN1 was downregulated. In addition, the overexpression of FN1 restored the abilities of cell migration, invasion and proliferation in Eca-109 cells. Further studies indicated that lnc-ABCA12-3 acted as a competing endogenous RNA for miR-200b-3p to regulate FN1 expression. In conclusion, these results suggest that lnc-ABCA12-3 is a novel oncogene in tumorigenesis and that its high expression is related to a poor prognosis for patients with ESCC. lnc-ABCA12-3 promotes cell migration, invasion, and proliferation via the regulation of FN1 in ESCC. Our data suggest that lnc-ABCA12-3 might serve as a potential prognostic biomarker and therapeutic target for ESCC.

Long noncoding RNA OIP5-AS1 in cancer

Long noncoding RNAs (lncRNAs) can be over two hundred nucleotides in length and lack an obvious open reading frame (ORF). Interestingly, these RNAs form a group of nucleic acids involved in a variety of diverse cellular mechanisms involving proliferation, differentiation, apoptosis,and senescence. Given these characteristics, it is not unexpected that the aberrant expression of certain lncRNAs is strongly linked to oncogenesis and tumor advancement. OIP5-AS1, a prominent tumor-associated lncRNA, contributes to intricate cellular mechanisms during the evolution of malignant tumors. For example, it not only represses cyclin G-associated kinase (GAK) expression thus impacting mitosis, but also regulates cell proliferation and apoptosis in many cancers, including lung adenocarcinoma, breast, glioma and hepatoblastoma. In this paper, we review our current understanding of OIP5-AS1 in carcinogenesis and its potential application as a clinical biomarker or therapeutic target in malignancy.

Long noncoding RNA OIP5-AS1 promotes the progression of oral squamous cell carcinoma via regulating miR-338-3p/NRP1 axis

Opa-interacting protein 5 antisense RNA 1 (OIP5-AS1), a novel identified long noncoding RNA (lncRNA), has been suggested to serve as oncogene in multiple cancers. However, the functional involvement of OIP5-AS1 in oral squamous cell carcinoma (OSCC) was still unknown. The aims of this study were to investigate the functional role of OIP5-AS1 in OSCC and explore its potential mechanism. We found that OIP5-AS1 was up-regulated in OSCC tissues compared with adjacent non-tumor tissues. Loss-of-function experiments revealed that OIP5-AS1 knockdown significantly inhibited OSCC cell proliferation, migration and invasion in vitro, and retarded tumor growth in vivo. Mechanistically, OIP5-AS1 serves as a competing endogenous RNA of miR-338-3p and modulates the expression of neuropilin1 (NRP1), which has been identified as a downstream target gene of miR-338-3p in OSCC. Moreover, downregulation of miR-338-3p or overexpression of NRP1 partly reversed the inhibitory effect of OIP5-AS1 depletion on cell proliferation, migration and invasion. The current results provide evidences for the role of OIP5-AS1 in promoting OSCC progression by regulating miR-338-3p/NRP1 axis and suggest OIP5-AS1 as a potential therapy target for OSCC.

Ilex hainanensis Merr targets ITGAV to suppress the proliferation and metastasis of osteosarcoma cells

Background: Osteosarcoma (OS) is the most common primary malignant bone tumor. Hence, there is an urgent need to identify effective and safe therapeutic agents against OS. It has been reported that Ilex hainanensis Merr (IME) possesses antitumor properties. Integrin subunit alpha V (ITGAV) is important for the diagnosis, treatment, and prognosis of tumors.

Purpose: The objective of this study was to whether IME can play a role in the treatment of osteosarcoma by regulating ITGAV.

Methods: Western blot and real-time PCR were used to detect the expression of ITGAV in non-tumorous tissues, osteosarcoma tissues, and metastatic tumors. The expression of ITGAV in MG63, U2OS, and hFOB1. A total of 19 cells was determined through Western blotting and real-time PCR. The expression of ITGAV in OS cells treated with different concentrations of DDP was determined through Western blotting. Agter transfecting with control or si-ITGAV, and subsequently treated with control or 5 μmol/L DDP, MTT assay and transwell assay were used to detect the proliferaion and migration of cells. Western blot was used to detect the expression of ITGAV in cells treated with different concentrations of IME and MTT assay and transwell assay were used to detect the proliferaion and migration of cells. MG63 and U2OS cells were treated with control, 5 μmol/L DDP, 25 μmol/L IME, or 5 μmol/L DDP combined with 25 μmol/L IME, the expression of ITGAV was determined through Western blotting and real-time PCR. MTT assay and transwell assay were used to detect the proliferation and migration of cells. Inhibitory effect of IME on lung metastasis of osteosarcoma in vivo.

Results: ITGAV was highly expressed in tumors, with the highest expression found in metastatic tumors and higher in OS cells. A low concentration of DDP (5 μmol/L) inhibited the expression of ITGAV. However, ITGAV may be related to the development of resistance to DDP. Silencing of ITGAV downregulates the proliferation and migration of OS cells as the effect of low-concentration DDP (5 μmol/L). IME inhibited the proliferation and migration of MG63 and U2OS cells in a concentration-dependent manner and decreased the expression of ITGAV. MTT and Transwell assays showed that 25 μmol/L IME and 5 μmol/L DDP exhibited similar inhibitory effects on the proliferation and migration of OS cells. The combination of IME with DDP resulted in the amplification of these inhibitory effects. Both DDP and IME downregulated the expression of ITGAV, and the inhibition of ITGAV was amplified by the combination of IME with DDP. In-vivo studies have shown that IME and DDP, independently or in combination, may significantly inhibit the metastasis of OS to the lungs.

Conclusion: IME may reduce the resistance of OS cells to DDP to some extent.

The LncRNA LINC00963 facilitates osteosarcoma proliferation and invasion by suppressing miR-204-3p/FN1 axis

Purpose: It remains unclear that long noncoding RNAs' role in cancer initiation and progression, including osteosarcoma. Long noncoding RNA LINC00963 was found to be participated in carcinogenesis and progression of osteosarcoma. However, the molecular mechanisms of LINC00963 engaged in osteosarcoma (OS) still needs to be explored. Methods: LINC00963 and miR-204-3p RNA expression levels were quantified by PCR in OS tissues and cells. CCK 8 assay, wound healing assay and transwell migration and invasion assay were chosen to assess cell growth, viability, migration, and invasion. Luciferase reporter assays were performed to verify direct interaction between LINC00963 and miR-204-3p and miR-204-3p and Fibronectin-1. Western blot was conducted to evaluate Fibronectin-1 expression in OS cells. Results: LINC00963 was verified to be highly expressed in OS samples and cells. Specifically, elevated expression of LINC00963 was correlated with poor prognosis in patients. Furthermore, LINC00963 overexpression was found to promote proliferation, migration, and invasion in vitro. The luciferase reporter assay showed that LINC00963 can suppress miR-204-3p by directly binding miR-204-3p. Rescue experiment results indicated that function of LINC00963 in osteosarcoma was miR-204-3p dependant. Besides, we initially explored Fibronectin-1 (FN1) as the target of LINC00963/miR-204-3p axis in osteosarcoma. Conclusions: Our findings implied that LINC00963/miR-204-3p/FN1 can play an important role in proliferation and progression in osteosarcoma. LINC00963 has the potential to be a therapeutic target for osteosarcoma treatment.