Two novel splice variants of SOX2OT, SOX2OT-S1, and SOX2OT-S2 are coupregulated with SOX2 and OCT4 in esophageal squamous cell carcinoma

Neospora caninum infection specifically suppresses the expression of a host lncRNA XR_001919077.1 to facilitate parasite propagation by modulating host cell mitochondrial function and autophagy

Neospora caninum is one of the most common pathogens causing reproductive failure in ruminants (e.g., cattle and goats) worldwide. However, due to a poor understanding of the pathogenic mechanisms of N. caninum infection, no effective drugs and vaccines are currently available. Long non-coding RNAs (lncRNAs) have been reported to be important regulators involved in a great number of physiological and pathological processes. Our previous study found that N. caninum infection induced significantly aberrant expression of lncRNA profiles in caprine endometrial epithelial cells (EECs). In the present study, we found that N. caninum infection specifically suppressed the expression of a novel lncRNA, XR_001919077.1, and knockdown of XR_001919077.1 with small interfering RNA significantly promoted the propagation of N. caninum in caprine EECs. Rapid amplification of cDNA ends analysis generated six splice variants of XR_001919077.1, with lengths ranging from 592 to 694 nt. Transfection of the full length of each variant markedly inhibited the propagation of N. caninum in caprine EECs. Further study suggested that XR_001919077.1 acted as a sponge of Chi-miR-93-5p to promote the expression of sirt1, and the XR_001919077.1/Chi-miR-93-5p/sirt1 axis significantly delayed the in vitro growth of N. caninum in caprine EECs by regulating host cell mitochondrial function and autophagy. Our findings provide a novel insight to understand the interactions between N. caninum and host cells.IMPORTANCEThe uterus is an indispensable reproductive organ for embryo implantation and fetal growth. The endometrium is more vulnerable to infection by pathogenic microorganisms resulting in an increased risk of miscarriage. Neospora caninum is one of the most common pathogens causing miscarriage in ruminants and is able to naturally inhabit the uterus, with N. caninum tissue cysts found in the endometrium. Recent advances in N. caninum research have revealed aberrant expression of long non-coding RNA (lncRNA) profiles in infected caprine endometrial epithelial cells. In the present study, N. caninum, but not Toxoplasma gondii, which has similar morphological and biological features to N. caninum, specifically suppresses the expression of a host lncRNA, XR_ 001919077.1, to impair host's defense through the competitive endogenous RNA mechanism to modulate the host cell mitochondrial function and autophagy to facilitate parasite propagation. The findings suggest a novel immune evasion strategy of N. caninum to facilitate intracellular propagation and provide an alternative path to develop control strategies against neosporosis.

The emerging role of long non-coding RNA SOX2-OT in cancers and non-malignant diseases

SOX2 overlapping transcript (SOX2-OT) is a long non-coding RNA located at chromosome 3q26.33 in humans. Convincing data confirm that SOX2-OT is evolutionarily conserved and plays a significant role in various malignant and non-malignant diseases. In most cancers, the upregulation of SOX2-OT acts as an oncogenic factor, strongly correlating with tumor risk, adverse clinicopathological features, and poor prognosis. Mechanistically, SOX2-OT is regulated by seven transcription factors and influences cellular behavior by modulating SOX2 expression, competitively binding 20 types of miRNAs, stabilizing protein expression, or promoting protein ubiquitination. It also participates in epigenetic modifications and activates multiple signaling pathways to regulate cancer cell proliferation, apoptosis, migration, invasion, autophagy, immune evasion, and resistance to chemotherapy/targeted therapies. Additionally, SOX2-OT triggers apoptosis, oxidative stress, and inflammatory responses, contributing to neurodevelopmental disorders, cardiovascular diseases, and diabetes-related conditions. Genetic polymorphisms of SOX2-OT have also been linked to breast cancer, gastric cancer, recurrent miscarriage, sepsis, and eating disorders in patients with bipolar disorder. This review provides an overview of recent research progress on SOX2-OT in human diseases, highlights its substantial potential as a prognostic and diagnostic biomarker, and explores its future clinical applications.

Ezrin, a novel marker of ependymal cells, can be used to demonstrate their proliferation regulation after spinal cord injury in mice

Ependymal cells (EpCs), as a potential stem cell niche, have gained interest for their potential in vivo stem cell therapy for spinal cord injury (SCI). Heterogeneity of spinal EpCs may contribute to differences in the ability of spinal EpCs to proliferate, differentiate and transition after injury, while there is limited understanding of the regulation of these events. Our research found that ezrin (Ezr) was expressed highly in EpCs of the spinal cord, and its upregulation rapidly occurred after injury (6 h). It remained consistently highly expressed in proliferating EpCs, this occurs before pathological accumulation of it occurs in other glial and immune-related cells. Differential expression of Ezr, Arg3, Pvalb, Ccnd1, and Gmpr characterized distinct responses of EpCs to injury activity. Also, we uncovered the dynamic regulatory behavior of immature EpCs after injury. In contrast to constitutive expression in parenchymal tissues, injury factors upregulated guanosine monophosphate reductase (Gmpr) in arrested EpCs, unveiling a distinctive mechanism to regulate proliferation in EpCs following spinal cord injury.

Competing endogenous RNAs regulatory crosstalk networks: The messages from the RNA world to signaling pathways directing cancer stem cell development

Cancer stem cells (CSCs) are one of the cell types that account for cancer heterogeneity. The cancer cells arrest in G0 and generate non-CSC progeny through self-renewal and pluripotency, resulting in tumor recurrence, metastasis, and resistance to chemotherapy. They can stimulate tumor relapse and re-grow a metastatic tumor. So, CSCs is a promising target for eradicating tumors, and developing an anti-CSCs therapy has been considered. In recent years competing endogenous RNA (ceRNA) has emerged as a significant class of post-transcriptional regulators that affect gene expression via competition for microRNA (miRNA) binding. Furthermore, aberrant ceRNA expression is associated with tumor progression. Recent findings show that ceRNA network can cause tumor progression through the effect on CSCs. To overcome therapeutic resistance due to CSCs, we need to improve our current understanding of the mechanisms by which ceRNAs are implicated in CSC-related relapse. Thus, this review was designed to discuss the role of ceRNAs in CSCs' function. Targeting ceRNAs may open the path for new cancer therapeutic targets and can be used in clinical research.

The Potential Links between lncRNAs and Drug Tolerance in Lung Adenocarcinoma

Lung cancer patients treated with targeted therapies frequently respond well but invariably relapse due to the development of drug resistance. Drug resistance is in part mediated by a subset of cancer cells termed "drug-tolerant persisters" (DTPs), which enter a dormant, slow-cycling state that enables them to survive drug exposure. DTPs also exhibit stem cell-like characteristics, broad epigenetic reprogramming, altered metabolism, and a mutagenic phenotype mediated by adaptive mutability. While several studies have characterised the transcriptional changes that lead to the altered phenotypes exhibited in DTPs, these studies have focused predominantly on protein coding changes. As long non-coding RNAs (lncRNAs) are also implicated in the phenotypes altered in DTPs, it is likely that they play a role in the biology of drug tolerance. In this review, we outline how lncRNAs may contribute to the key characteristics of DTPs, their potential roles in tolerance to targeted therapies, and the emergence of genetic resistance in lung adenocarcinoma.

Discovery of putative long non-coding RNAs expressed in the eyes of Astyanax mexicanus (Actinopterygii: Characidae)

Astyanax mexicanus is a well-known model species, that has two morphotypes, cavefish, from subterranean rivers and surface fish, from surface rivers. They are morphologically distinct due to many troglomorphic traits in the cavefish, such as the absence of eyes. Most studies on A. mexicanus are focused on eye development and protein-coding genes involved in the process. However, lncRNAs did not get the same attention and very little is known about them. This study aimed to fill this knowledge gap, identifying, describing, classifying, and annotating lncRNAs expressed in the embryo's eye tissue of cavefish and surface fish. To do so, we constructed a concise workflow to assemble and evaluate transcriptomes, annotate protein-coding genes, ncRNAs families, predict the coding potential, identify putative lncRNAs, map them and predict interactions. This approach resulted in the identification of 33,069 and 19,493 putative lncRNAs respectively mapped in cavefish and surface fish. Thousands of these lncRNAs were annotated and identified as conserved in human and several species of fish. Hundreds of them were validated in silico, through ESTs. We identified lncRNAs associated with genes related to eye development. This is the case of a few lncRNAs associated with sox2, which we suggest being isomorphs of the SOX2-OT, a lncRNA that can regulate the expression of sox2. This work is one of the first studies to focus on the description of lncRNAs in A. mexicanus, highlighting several lncRNA targets and opening an important precedent for future studies focusing on lncRNAs expressed in A. mexicanus.

Towards Understanding the Key Signature Pathways Associated from Differentially Expressed Gene Analysis in an Indian Prostate Cancer Cohort

Prostate cancer (PCa) is one of the most prevalent cancers among men in India. Although studies on PCa have dealt with genetics, genomics, and the environmental influence in the causality of PCa, not many studies employing the Next Generation Sequencing (NGS) approaches of PCa have been carried out. In our previous study, we identified some causal genes and mutations specific to Indian PCa using Whole Exome Sequencing (WES). In the recent past, with the help of different cancer consortiums such as The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC), along with differentially expressed genes (DEGs), many cancer-associated novel non-coding RNAs have been identified as biomarkers. In this work, we attempt to identify differentially expressed genes (DEGs) including long non-coding RNAs (lncRNAs) associated with signature pathways from an Indian PCa cohort using the RNA-sequencing (RNA-seq) approach. From a cohort of 60, we screened six patients who underwent prostatectomy; we performed whole transcriptome shotgun sequencing (WTSS)/RNA-sequencing to decipher the DEGs. We further normalized the read counts using fragments per kilobase of transcript per million mapped reads (FPKM) and analyzed the DEGs using a cohort of downstream regulatory tools, viz., GeneMANIA, Stringdb, Cytoscape-Cytohubba, and cbioportal, to map the inherent signatures associated with PCa. By comparing the RNA-seq data obtained from the pairs of normal and PCa tissue samples using our benchmarked in-house cuffdiff pipeline, we observed some important genes specific to PCa, such as STEAP2, APP, PMEPA1, PABPC1, NFE2L2, and HN1L, and some other important genes known to be involved in different cancer pathways, such as COL6A1, DOK5, STX6, BCAS1, BACE1, BACE2, LMOD1, SNX9, CTNND1, etc. We also identified a few novel lncRNAs such as LINC01440, SOX2OT, ENSG00000232855, ENSG00000287903, and ENST00000647843.1 that need to be characterized further. In comparison with publicly available datasets, we have identified characteristic DEGs and novel lncRNAs implicated in signature PCa pathways in an Indian PCa cohort which perhaps have not been reported. This has set a precedent for us to validate candidates further experimentally, and we firmly believe this will pave a way toward the discovery of biomarkers and the development of novel therapies.

Crosstalk between SOX Genes and Long Non-Coding RNAs in Glioblastoma

Glioblastoma (GBM) continues to be the most devastating primary brain malignancy. Despite significant advancements in understanding basic GBM biology and enormous efforts in developing new therapeutic approaches, the prognosis for most GBM patients remains poor with a median survival time of 15 months. Recently, the interplay between the SOX (SRY-related HMG-box) genes and lncRNAs (long non-coding RNAs) has become the focus of GBM research. Both classes of molecules have an aberrant expression in GBM and play essential roles in tumor initiation, progression, therapy resistance, and recurrence. In GBM, SOX and lncRNAs crosstalk through numerous functional axes, some of which are part of the complex transcriptional and epigenetic regulatory mechanisms. This review provides a systematic summary of current literature data on the complex interplay between SOX genes and lncRNAs and represents an effort to underscore the effects of SOX/lncRNA crosstalk on the malignant properties of GBM cells. Furthermore, we highlight the significance of this crosstalk in searching for new biomarkers and therapeutic approaches in GBM treatment.

SOX2OT lncRNA Inhibition Suppresses the Stemness Characteristics of Esophageal Tumorspheres

BACKGROUND

SOX2OT is a novel cancer associated long non-coding RNA (LncRNA) with higher expression in variable tumor tissues, including esophageal squamous cell carcinoma (ESCC). It also plays an important function in embryonic neuronal development. Regarding its function in both stemness and carcinogenesis, here, we aimed to investigate its expression and function in tumorspheres of the esophagus using the RNAi method.

MATERIAL & METHODS

Two esophageal squamous cancer cells (ESCC): KYSE30 and YM1 cells were used for sphere enrichment. Cells were transfected with SOX2OT targeting and control siRNA. The size and the number of spheres were measured using light microscopy. Gene expression of the pluripotency genes was measured by qRT-PCR and docetaxel chemoresistance was assessed by MTS viability assay.

RESULTS

Our findings showed that ESCC tumorspheres overexpress SOX2OT gene along with other stemness genes (SOX2, OCT4A, and Nanog) compared to their original cancer cells. RNAi experiments indicated that SOX2OT knockdown can suppress the stemness-related gene expression, sphere formation ability (both size and number), and docetaxel resistance as three of the main cancer stem cell characteristics of tumorspheres.

CONCLUSION

Altogether our results showed the regulatory role of SOX2OT in pluripotency and stemness in ESCC tumorspheres. Our results suggest a potential application of SOX2OT inhibition in combination with docetaxel for ESCC inhibition in vitro.

iPSCs derived from esophageal atresia patients reveal SOX2 dysregulation at the anterior foregut stage

A series of well-regulated cellular and molecular events result in the compartmentalization of the anterior foregut into the esophagus and trachea. Disruption of the compartmentalization process leads to esophageal atresia/tracheoesophageal fistula (EA/TEF). The cause of EA/TEF remains largely unknown. Therefore, to mimic the early development of the esophagus and trachea, we differentiated induced pluripotent stem cells (iPSCs) from EA/TEF patients, and iPSCs and embryonic stem cells from healthy individuals into mature three-dimensional esophageal organoids. CXCR4, SOX17 and GATA4 expression was similar in both patient-derived and healthy endodermal cells. The expression of the key transcription factor SOX2 was significantly lower in the patient-derived anterior foregut. We also observed an abnormal expression of NKX2.1 (or NKX2-1) in the patient-derived mature esophageal organoids. At the anterior foregut stage, RNA sequencing revealed the critical genes GSTM1 and RAB37 to be significantly lower in the patient-derived anterior foregut. We therefore hypothesize that a transient dysregulation of SOX2 and the abnormal expression of NKX2.1 in patient-derived cells could be responsible for the abnormal foregut compartmentalization.

The functions of lncRNAs in the HPV-negative cervical cancer compared with HPV-positive cervical cancer

Cervical cancer is one of the most common female malignancies. Human papillomaviruses (HPV) are the main causative agents of virtually all cervical carcinomas. Nevertheless, emerging evidence has demonstrated that a small proportion of cervical cancer patients are HPV negative. Long noncoding RNAs (lncRNAs) have been identified to play a crucial role in cervical cancer development. Here, this review describes the incidence and development of HPV-negative cervical cancer. Moreover, HPV-negative cervical cancers are more likely diagnosed at non-squamous type, older ages, more advanced stage and metastases, and associated with poorer prognosis as compared to HPV-positive cervical cancer. Furthermore, the significant role and functions of lncRNAs underlying HPV-negative cervical cancer is clarified.

Long Non-Coding RNAs in Pancreatic Cancer: Biologic Functions, Mechanisms, and Clinical Significance

Despite tremendous efforts devoted to research in pancreatic cancer (PC), the mechanism underlying the tumorigenesis and progression of PC is still not completely clear. Additionally, ideal biomarkers and satisfactory therapeutic strategies for clinical application in PC are still lacking. Accumulating evidence suggests that long non-coding RNAs (lncRNAs) might participate in the pathogenesis of diverse cancers, including PC. The abnormal expression of lncRNAs in PC is considered a vital factor during tumorigenesis that affects tumor cell proliferation, migration, invasion, apoptosis, angiogenesis, and drug resistance. With this review of relevant articles published in recent years, we aimed to summarize the biogenesis mechanism, classifications, and modes of action of lncRNAs and to review the functions and mechanisms of lncRNAs in PC. Additionally, the clinical significance of lncRNAs in PC was discussed. Finally, we pointed out the questions remaining from recent studies and anticipated that further investigations would address these gaps in knowledge in this field.

Zooming in on Long Non-Coding RNAs in Ewing Sarcoma Pathogenesis

Ewing sarcoma (ES) is a rare aggressive cancer of bone and soft tissue that is mainly characterized by a reciprocal chromosomal translocation. As a result, about 90% of cases express the EWS-FLI1 fusion protein that has been shown to function as an aberrant transcription factor driving sarcomagenesis. ES is the second most common malignant bone tumor in children and young adults. Current treatment modalities include dose-intensified chemo- and radiotherapy, as well as surgery. Despite these strategies, patients who present with metastasis or relapse still have dismal prognosis, warranting a better understanding of treatment resistant-disease biology in order to generate better prognostic and therapeutic tools. Since the genomes of ES tumors are relatively quiet and stable, exploring the contributions of epigenetic mechanisms in the initiation and progression of the disease becomes inevitable. The search for novel biomarkers and potential therapeutic targets of cancer metastasis and chemotherapeutic drug resistance is increasingly focusing on long non-coding RNAs (lncRNAs). Recent advances in genome analysis by high throughput sequencing have immensely expanded and advanced our knowledge of lncRNAs. They are non-protein coding RNA species with multiple biological functions that have been shown to be dysregulated in many diseases and are emerging as crucial players in cancer development. Understanding the various roles of lncRNAs in tumorigenesis and metastasis would determine eclectic avenues to establish therapeutic and diagnostic targets. In ES, some lncRNAs have been implicated in cell proliferation, migration and invasion, features that make them suitable as relevant biomarkers and therapeutic targets. In this review, we comprehensively discuss known lncRNAs implicated in ES that could serve as potential biomarkers and therapeutic targets of the disease. Though some current reviews have discussed non-coding RNAs in ES, to our knowledge, this is the first review focusing exclusively on ES-associated lncRNAs.

A Pleiotropic Role of Long Non-Coding RNAs in the Modulation of Wnt/β-Catenin and PI3K/Akt/mTOR Signaling Pathways in Esophageal Squamous Cell Carcinoma: Implication in Chemotherapeutic Drug Response

Despite the availability of modern techniques for the treatment of esophageal squamous cell carcinoma (ESCC), tumor recurrence and metastasis are significant challenges in clinical management. Thus, ESCC possesses a poor prognosis and low five-year overall survival rate. Notably, the origin and recurrence of the cancer phenotype are under the control of complex cancer-related signaling pathways. In this review, we provide comprehensive knowledge about long non-coding RNAs (lncRNAs) related to Wnt/β-catenin and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway in ESCC and its implications in hindering the efficacy of chemotherapeutic drugs. We observed that a pool of lncRNAs, such as HERES, TUG1, and UCA1, associated with ESCC, directly or indirectly targets various molecules of the Wnt/β-catenin pathway and facilitates the manifestation of multiple cancer phenotypes, including proliferation, metastasis, relapse, and resistance to anticancer treatment. Additionally, several lncRNAs, such as HCP5 and PTCSC1, modulate PI3K/Akt/mTOR pathways during the ESCC pathogenesis. Furthermore, a few lncRNAs, such as AFAP1-AS1 and LINC01014, block the efficiency of chemotherapeutic drugs, including cisplatin, 5-fluorouracil, paclitaxel, and gefitinib, used for ESCC treatment. Therefore, this review may help in designing a better therapeutic strategy for ESCC patients.

Long noncoding RNA SOX2OT promotes pancreatic cancer cell migration and invasion through destabilizing FUS protein via ubiquitination

Pancreatic cancer is a highly aggressive and lethal digestive system malignancy. Our previous studies revealed the correlation of high levels of lncRNA SOX2OT expression with patients’ poor survival outcomes, the promoting role of SOX2OT in proliferation and cycle progression of pancreatic cancer cells, and the in vivo binding of SOX2OT to RNA binding protein FUS, which destabilized the protein expression of FUS. However, the mechanism of SOX2OT binding and inhibiting FUS protein stability remains unclear. In this study, we performed RNA pull-down, cycloheximide-chase, and ubiquitination assays to determine the effect of SOX2OT on FUS ubiquitination, and explored the specific regulatory mechanism of SOX2OT–FUS axis in pancreatic cancer cell migration, invasion, in vivo tumor growth, and metastasis through RNA sequencing. We found that SOX2OT binds to FUS through its 5′ and 3′ regions, resulting in FUS ubiquitination and degradation. The SOX2OT–FUS regulatory axis promotes migration, invasion, tumor growth, and metastasis ability of pancreatic cancer cells. The in-depth elaboration of the SOX2OT–FUS regulatory axis in pancreatic cancer may clarify the mechanism of action of SOX2OT and provide new ideas for pancreatic cancer treatment.

Increasing Gene Editing Efficiency for CRISPR-Cas9 by Small RNAs in Pluripotent Stem Cells

Gene manipulations of human induced pluripotent stem cells (iPSCs) by CRISPR-Cas9 genome engineering are widely used for disease modeling and regenerative medicine applications. There are two competing pathways, non-homologous end joining (NHEJ) and homology directed repair (HDR) that correct the double-strand break generated by CRISPR-Cas9. Here, we improved gene editing efficiency of gene knock-in (KI) in iPSCs with minimum components by manipulating the Cas9 expression vector. Either we inserted short hairpin RNA expression cassettes to downregulate DNAPK and XRCC4, two main players of the NHEJ pathway, or we increased cell survival by inserting an anti-apoptotic expression cassette of miRNA-21 into the Cas9 vector. For an easy readout, the pluripotency gene SOX2 was targeted with a T2A-tdTomato reporter construct. In vitro downregulating DNAPK and XRCC4 increased the targeting efficiency of SOX2 KI by around twofold. Furthermore, co-expression of miRNA-21 and Cas9 improved the efficiency of SOX2 KI by around threefold. Altogether, our strategies provide a simple and valuable approach for efficient CRISPR-Cas9 gene editing in iPSCs.

Correlations between Overexpression of SOX2OT Long Non-coding RNA and Susceptibility to Breast Cancer

BACKGROUND AND OBJECTIVE

The SOX2OT lcnRNA has been recognized as a positive regulator in the transcription regulation of the SOX2 gene. Recent studies have approved the dysregulation of SOX2OT lncRNA expression patterns in some common cancer types, including esophageal, lung, and breast cancer. The objective of the present study was to investigate the correlation between overexpression of SOX2OT lcnRNA and susceptibility to breast cancer.

METHODS

SOX2OT lncRNA expression profiling in 15 breast cancer and normal tumour-adjacent breast tissue samples was performed by using qRT-PCR. To evaluate the diagnostic potential of the SOX2OT lncRNA, we performed ROC curve analyses.

RESULTS

The expression of SOX2OT lncRNA in patients suffering from breast cancer revealed a significant overexpression in comparison with the healthy group (P<0.001). Significantly, the elevated circulating SOX2OT lncRNA was found specific to breast cancer and could differentiate breast cancer from controls with 100% of both sensitivity and specificity. Based on the Kaplan- Meier analysis, there was no significant correlation between SOX2OT lcnRNA expression and overall survival.

CONCLUSION

The results confirmed the association between breast cancer and higher SOX2OT lncRNA expression. According to the ROC curve results, SOX2OT lcnRNA could be a new measurable indicator of the breast cancer and a potential therapeutic target for breast cancer patients.

Identifying SOX2-OT transcript that is responsible for regulating SOX2 in cancer cells and embryonic stem cells

SOX2 overlapping transcript (SOX2-OT) is an evolutionarily conserved long non-coding RNA (lncRNA) whose intronic region contains the transcript of pluripotency gene SRY-box transcription factor 2 (SOX2). It has been suggested that SOX2-OT can regulate its overlapping gene, SOX2. Studies demonstrated that elevated SOX2-OT promotes SOX2 expression in cancer cells, whereas levels of SOX2-OT are inversely correlated with levels of SOX2 in embryonic stem cells. It is not clear why there is a tremendous discrepancy in the regulation of SOX2 by SOX2-OT in cancer cells and embryonic stem cells. Due to the diversified transcription of the SOX2-OT gene, we hypothesize that differential expression of transcripts of the SOX2-OT gene in cancer cells and embryonic stem cells may contribute to the divergence in the regulatory relationship of SOX2-OT and SOX2. A CRISPR screening platform can be leveraged to systemic evaluate which transcript of the SOX2-OT gene may be responsible for upregulation or downregulation of SOX2 in cancer cells and embryonic stem cells, respectively.

SOX2OT Long Noncoding RNA Is Regulated by the UPR in Oestrogen Receptor-Positive Breast Cancer

Endoplasmic reticulum (ENR) stress perturbs cell homeostasis and induces the unfolded protein response (UPR). In breast cancer, this process is activated by oestrogen deprivation and is associated with tamoxifen resistance. We present evidence that the transcription factor SOX2 and the long noncoding RNA SOX2 overlapping transcript (SOX2OT) are upregulated in oestrogen receptor-positive (ER+) breast cancer and in response to oestrogen deprivation. We examined the effect of the UPR on SOX2 and SOX2OT expression and the effect of SOX2OT on UPR pathways in breast cancer cell lines. The induction of the UPR by thapsigargin or glucose deprivation upregulates SOX2OT expression. This upregulation is also shown with the anti-oestrogen 4OH-tamoxifen and mTOR inhibitor everolimus in ER + breast cancer cells that are sensitive to oestrogen deprivation or everolimus treatment. SOX2OT overexpression decreased BiP and PERK expression. This effect of SOX2OT overexpression was confirmed on BiP and PERK pathway by q-PCR. Our results show that a long noncoding RNA regulates the UPR and evince a new function of SOX2OT as a participant of ENR stress reprogramming of breast cancer cells.

The emerging role of long noncoding RNAs in esophageal carcinoma: from underlying mechanisms to clinical implications

Long noncoding RNAs (lncRNAs), a type of transcriptional product more than 200 nucleotides in length, have emerged as crucial regulators in human cancers. Accumulating data have recently indicated relationships between lncRNAs and esophageal carcinoma (EC). Of note, lncRNAs act as decoys/sponges, scaffolds, guides, and signals to regulate the expression of oncogenes or tumor suppressors at epigenetic, post-transcriptional, and protein levels, through which they exert their unique EC-driving or EC-suppressive functions. Moreover, the features of EC-related lncRNAs have been gradually exploited for developing novel diagnostic and therapeutic strategies in clinical scenarios. LncRNAs have the potential to be used as diagnostic and prognostic indicators individually or in combination with other clinical variables. Beyond these, although the time is not yet ripe, therapeutically targeting EC-related lncRNAs via gene editing, antisense oligonucleotides, RNA interference, and small molecules is likely one of the most promising therapeutic strategies for the next generation of cancer treatment. Herein, we focus on summarizing EC-driving/suppressive lncRNAs, as well as discussing their different features regarding expression profiles, modes of action, and oncological effects. Moreover, we further discuss current challenges and future developing possibilities of capitalizing on lncRNAs for EC early diagnosis and treatment.

LncRNA SOX2-OT regulates AKT/ERK and SOX2/GLI-1 expression, hinders therapy, and worsens clinical prognosis in malignant lung diseases

The involvement of LncRNA SOX2-overlapping transcript (SOX2-OT), SOX2, and GLI-1 transcription factors in cancer has been well documented. Nonetheless, it is still unknown whether co-expressed SOX2-OT/SOX2 or SOX2-OT/SOX2/GLI-1 axes are epigenetically/transcriptionally involved in terms of resistance to oncology therapy and in poorer clinical outcomes for patients with lung cancer. We evaluated the role of SOX2-OT/SOX2 and SOX2-OT/SOX2/GLI-1 axes using RT-qPCR, western blot, immunofluorescence analyses, gene silencing, cellular cytotoxic, and ChIP-qPCR assays on human cell lines, solid lung malignant tumors, and normal lung tissue. We detected that the SOX2-OT/SOX2/GLI-1 axis promotes resistance to tyrosine kinase inhibitor (TKI)-erlotinib and cisplatin-based therapy. Evidence from this study show that SOX2-OT modulates the expression/activation of EGFR-pathway members AKT/ERK. Further, both SOX2-OT and GLI-1 genes are epigenetically regulated at their promoter sequences, in an LncRNA SOX2-OT-dependent manner, mainly through modifying the enrichment of the activation histone mark H3K4me3/H3K27Ac, versus the repressive histone mark H3K9me3/H3K27me3. In addition, we identified that inhibition of SOX2-OT and reduced expression of SOX2/GLI-1 sensitizes lung cancer cells to EGFR/TKI-erlotinib or cisplatin-based treatment. Finally, we show that high co-expression of SOX2-OT/SOX2 transcripts and SOX2/GLI-1 proteins appears to correlate with a poor clinical prognosis and lung malignant phenotype. Collectively, these results present evidence that LncRNA SOX2-OT modulates an orchestrated resistance mechanism, promoting poor prognosis and human lung malignancy through genetic, epigenetic, and post-translational mechanisms.

Potential of long non-coding RNAs as a therapeutic target and molecular markers in glioblastoma pathogenesis

Glioblastoma (GB) is by far the most hostile type of malignant tumor that primarily affects the brain and spine, derived from star-shaped glial cells that are astrocytes and oligodendrocytes. Despite of significant efforts in recent years in glioblastoma research, the clinical efficacy of existing medical intervention is still limited and very few potential diagnostic markers are available. Long non-coding RNAs (lncRNAs) that lacks protein-coding capabilities were previously thought to be "junk sequences" in mammalian genomes are quite indispensible epigenetic regulators that can positively or negatively regulate gene expression and nuclear architecture, with significant roles in the initiation and development of tumors. Nevertheless, the precise mechanism of these distortedly expressed lncRNAs in glioblastoma pathogenesis is not yet fully understood. Since the advent of high-throughput sequencing technologies, more and more research have elucidated that lncRNAs are one of the most promising prognostic biomarkers and therapeutic targets for glioblastoma. In this paper, I briefly outlined the existing findings of lncRNAs. And also summarizes the profiles of different lncRNAs that have been broadly classified in glioblastoma research, with emphasis on both their prognostic and therapeutic values.

Long Noncoding RNA SOX2-OT: Regulations, Functions, and Roles on Mental Illnesses, Cancers, and Diabetic Complications

SRY-box transcription factor 2 (SOX2) overlapping transcript (SOX2-OT) is an evolutionarily conserved long noncoding RNA. Its intronic region contains the SOX2 gene, the major regulator of the pluripotency of embryonic stem cells. The human SOX2-OT gene comprises multiple exons and has multiple transcription start sites and generates hundreds of transcripts. Transcription factors (IRF4, AR, and SOX3), transcriptional inhibitors (NSPc1, MTA3, and YY1), and miRNAs (miR-211 and miR-375) have been demonstrated to control certain SOX2-OT transcript level at the transcriptional or posttranscriptional levels. Accumulated evidence indicates its crucial roles in the regulation of the SOX2 gene, miRNAs, and transcriptional process. Restricted expression of SOX2-OT transcripts in the brain results in the association between SOX2-OT single nucleotide polymorphisms and mental illnesses such as schizophrenia and anorexia nervosa. SOX2-OT is notably elevated in tumor tissues, and a high level of SOX2-OT is well correlated with poor clinical outcomes in cancer patients, leading to the establishment of its role as an oncogene and a prognostic or diagnostic biomarker for cancers. The emerging evidence supports that SOX2-OT mediates diabetic complications. In summary, SOX2-OT has diversified functions and could be a therapeutic target for various diseases.

Long non-coding RNAs in lung cancer: implications for lineage plasticity-mediated TKI resistance

The efficacy of targeted therapy in non-small-cell lung cancer (NSCLC) has been impeded by various mechanisms of resistance. Besides the mutations in targeted oncogenes, reversible lineage plasticity has recently considered to play a role in the development of tyrosine kinase inhibitors (TKI) resistance in NSCLC. Lineage plasticity enables cells to transfer from one committed developmental pathway to another, and has been a trigger of tumor adaptation to adverse microenvironment conditions including exposure to various therapies. More importantly, besides somatic mutation, lineage plasticity has also been proposed as another source of intratumoural heterogeneity. Lineage plasticity can drive NSCLC cells to a new cell identity which no longer depends on the drug-targeted pathway. Histological transformation and epithelial–mesenchymal transition are two well-known pathways of lineage plasticity-mediated TKI resistance in NSCLC. In the last decade, increased re-biopsy practice upon disease recurrence has increased the recognition of lineage plasticity induced resistance in NSCLC and has improved our understanding of the underlying biology. Long non-coding RNAs (lncRNAs), the dark matter of the genome, are capable of regulating variant malignant processes of NSCLC like the invisible hands. Recent evidence suggests that lncRNAs are involved in TKI resistance in NSCLC, particularly in lineage plasticity-mediated resistance. In this review, we summarize the mechanisms of lncRNAs in regulating lineage plasticity and TKI resistance in NSCLC. We also discuss how understanding these themes can alter therapeutic strategies, including combination therapy approaches to overcome TKI resistance.

Emerging roles of long noncoding RNAs in cholangiocarcinoma: Advances and challenges

Cholangiocarcinoma (CCA), a cancer with a relatively low incidence rate, is usually associated with poor prognosis. Current modalities for the diagnosis and treatment of CCA patients are still far from satisfactory. In recent years, numerous long noncoding RNAs (lncRNAs) have been identified as crucial players in the development of various cancers, including CCA. Abnormally expressed lncRNAs in CCA, regulated by some upstream molecules, significantly influence the biological behavior of tumor cells and are involved in tumor development through various mechanisms, including interactions with functional proteins, participation in competing for endogenous RNA (ceRNA) regulatory networks, activation of cancer‐related signaling pathways and epigenetic modification of gene expression. Furthermore, several lncRNAs are closely associated with the clinicopathological features of CCA patients, and are promising biomarkers for diagnosing and prognostication of CCA. Some of these lncRNAs play an important role in chemotherapy drug resistance. In addition, lncRNAs have also been shown to be involved in the inflammation microenvironment of CCA and malignant outcome of CCA risk factors, such as cholestatic liver diseases. In view of the difficulty of diagnosing CCA, more attention should be paid to detectable lncRNAs in the serum or bile. This review summarizes the recent knowledge on lncRNAs in CCA and provides a new outlook on the molecular mechanisms of CCA development from the perspective of lncRNAs. Moreover, we also discussed the limitations of the current studies and differential expression of lncRNAs in different types of CCA.

Evaluating the effect of siRNA on SOX2OT expression in the human neuron-committed teratocarcinoma NT2 cell line

Non-coding RNA elongated (lncRNAs) have recently attracted as molecules that regulate gene expression of the pluripotent properties (pluripotency) of stem cells. Recently our colleagues examined the role of one of these RNAs called SOX2OT in esophageal squamous cell carcinoma, and found a concomitant increase in its expression with some regulatory genes of cell proliferation. In the present study, using the design of suitable primers from SOX2OT gene, we investigated the effect of siRNA on expression of SOX2OT.

A prognostic index based on a fourteen long non-coding RNA signature to predict the recurrence-free survival for muscle-invasive bladder cancer patients

Background

Bladder cancer (BC) is regarded as one of the most fatal cancer around the world. Nevertheless, there still lack of sufficient markers to predict the prognosis of BC patients. Herein, we aim to establish a prognosis predicting signature based on long-noncoding RNA (lncRNA) for the invasive BC patients.

Methods

The lncRNA expression profile was downloaded from The Cancer Genome Atlas (TCGA) database, along with the correlated clinicopathological information. The univariate Cox regression test was employed to screen out the recurrence-free survival (RFS)-related lncRNAs. Then, the LASSO method was conducted to construct the signature based on these RFS-related lncRNA candidates. Genes correlated with these fourteen lncRNAs were extracted from the mRNA expression profile, with the Pearson correlation coefficient > 0.60 or < − 0.40. Subsequently, the Proteomap pathway enrichment analyses were conducted to classify the function of these correlated genes. Furthermore, the multivariate analyses were executed to reveal the independent role of the proposed signature with the clinicopathological features.

Results

We established an lncRNA-based RFS predicting signature by the LASSO Cox regression test, and proved its usage and stability on both the training and validation cohorts by the Kaplan-Meier and receiver operating characteristic (ROC) curves. Notably, the multivariate Cox regression analysis found that our classifier was an independent indicator for muscle-invasive BC patients rather than sex, age and tumor grade, with higher predictive value than the existing ones. Besides, we did the pathway analyses for these genes that highly correlated with the proposed fourteen lncRNAs, as well as the differentially expressed genes (DEGs) derived from the high-risk vs. low-risk groups, and the recurrence vs. non-recurrence groups, respectively. Notably, these results were consistent, and these genes were mostly enriched in the transcription factors, G protein-coupled receptors, MAPK signaling pathways, which were proved significantly associated with tumor progression and drug resistance.

Conclusions

Our results suggested that the fourteen-lncRNA-based RFS predicting signature is an independent indicator for BC patients. Further prospective studies with more samples are needed to verify our findings.

Long Noncoding RNA SOX2-OT Knockdown Inhibits Proliferation and Metastasis of Prostate Cancer Cells Through Modulating the miR-452-5p/HMGB3 Axis and Inactivating Wnt/β-Catenin Pathway

Background: Recent studies have proven that abnormal expression of long noncoding RNAs (lncRNAs) often contributes to growth and invasion of cancer cells. The purpose of this study was to investigate the biological function and regulatory mechanism of lncRNA SOX2 overlapping transcript (SOX2-OT) in prostate cancer (PCa) progression. Materials and Methods: The expression of SOX2-OT, microRNA-452-5p (miR-452-5p), and high mobility group box 3 (HMGB3) was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Flow cytometry was performed to determine the cell cycle distribution. Western blot assay was conducted to measure the protein levels of cyclin D1, p21, p27, E-cadherin, vimentin, and N-cadherin. The interaction between miR-452-5p and SOX2-OT or HMGB3 was predicted by bioinformatics analysis and verified by dual-luciferase reporter assay and RNA immunoprecipitation assay. The mice xenograft model was established to investigate the role of SOX2-OT in vivo. Results: SOX2-OT and HMGB3 were upregulated, whereas miR-452-5p was downregulated in PCa tissues and cells. Knockdown of SOX2-OT inhibited PCa cell growth and metastasis. MiR-452-5p could directly bind to SOX2-OT and its knockdown reversed the inhibitory effects of SOX2-OT interference on growth and metastasis of PCa cells. HMGB3 was a direct target of miR-452-5p and its knockdown weakened the promotive effects of miR-452-5p silence on growth and metastasis of PCa cells. Moreover, HMGB3 expression was inversely regulated by miR-452-5p and positively modulated by SOX2-OT. Furthermore, SOX2-OT activated the Wnt/β-catenin signaling pathway through increasing HMGB3 expression. Finally, SOX2-OT knockdown hindered tumor growth in vivo by regulating miR-452-5p/HMGB3 axis. Conclusions: SOX2-OT downregulation limited PCa cell growth and metastasis by regulating miR-452-5p/HMGB3 axis and inactivating Wnt/β-catenin signaling pathway, which might offer lncRNA-directed diagnosis and therapy for PCa.

Long non-coding RNA Sox2 overlapping transcript (SOX2OT) promotes multiple myeloma progression via microRNA-143-3p/c-MET axis

Long non-coding RNA Sox2 overlapping transcript (SOX2OT) was reported to be involved in progression of multiple cancers. However, the role and mechanism of SOX2OT in multiple myeloma (MM) has yet to be unravelled. In the present study, elevated SOX2OT levels are reported in MM cell lines and patient samples as compared to normal plasma cells (nPCs) and healthy donors, respectively. Knock-down of SOX2OT led to a significant inhibition of cell proliferation, arrested cells at G0/G1 phase and induced cell apoptosis in MM samples in vitro, as well as slowed the growth of tumours in vivo. Additionally, our data indicated that SOX2OT functioned as a competing endogenous RNA (ceRNA) in MM cells that regulated miR-144-3p expression. Repression of miR-144-3p reversed the inhibition of MM development due to SOX2OT knock-down. Our data also revealed that SOX2OT regulated the expression of the cellular-mesenchymal to epithelial transition factor (c-MET, a known target of miR-143-3p) by functioning as a sponge of miR-144-3p in MM samples. These data support that SOX2OT promotes MM progression through regulating the miR-144-3p/c-MET axis, suggesting that SOX2OT might be as a potential therapeutic target for MM.

LncRNA SOX2OT affects cervical cancer cell growth, migration and invasion by regulating SOX2

Long non-coding RNA (lncRNA) SOX2 overlapping transcript (SOX2OT) has been shown to play an oncogenic role in diverse cancers, generating eight transcript variants. SOX2 is located in the third intron of SOX2OT. However, the biological function of SOX2OT in cervical cancer and implication with SOX2 remain to be further explored. In this study, we screened the expression pattern of different SOX2OT transcript variants in cervical cancer cells. Interestingly, both high-expression levels of SOX2OT transcript 7 (SOX2OT-7) and SOX2 were detected in C-33A (HPV^-) and SiHa (HPV16⁺) cells. Thus, C-33A and SiHa cells were conducted to investigate the effects of SOX2OT on cell growth, migration and invasion. Finally, rescue experiments were performed to confirm the role of SOX2 in SOX2OT-mediated regulation of cervical cancer progression. The results showed that knockdown of SOX2OT suppressed cell viability, arrested cell cycle and ameliorated migration and invasion ability of C-33A and SiHa cells. Ectopic expression of SOX2OT-7 exacerbated cervical cancer cell proliferation, migration and invasion. In addition, we found that the expression levels and protein stability of SOX2 were positively regulated by SOX2OT. Inhibition of SOX2 could block the malignant phenotypes of C-33A and SiHa cells by SOX2OT-7. In conclusion, these findings indicate that lncRNA SOX2OT contributes to the growth, migration and invasion of cervical cancer cells by modulating SOX2. Importantly, we demonstrate that the transcript SOX2OT-7 may be a novel and promising biomarker for both HPV^- and HPV16⁺ cervical cancer.

SOX2OT Long Noncoding RNA Is Regulated by the UPR in Oestrogen Receptor-Positive Breast Cancer

Endoplasmic reticulum (ER) stress perturbs cell homeostasis and induces the unfolded protein response (UPR). In breast cancer, this process is activated by oestrogen deprivation and is associated with tamoxifen resistance. We present evidence that the transcription factor SOX2 and the long noncoding RNA SOX2 overlapping transcript (SOX2OT) are up-regulated in oestrogen receptor-positive (ER+) breast cancer and in response to oestrogen deprivation. We examined the effect of the UPR on SOX2 and SOX2OT expression, and the effect of SOX2OT on UPR pathways in breast cancer cell lines. The induction of the UPR by thapsigargin or glucose deprivation up-regulates SOX2OT expression. This up-regulation is also shown with the anti-oestrogen 4OH-tamoxifen and mTOR inhibitor everolimus in ER + breast cancer cells that are sensitive to oestrogen deprivation or everolimus treatment. SOX2OT overexpression decreased BiP and PERK expression. This effect of SOX2OT overexpression was confirmed on BiP and PERK pathway by q-PCR. Our results show that a long noncoding RNA regulates the UPR and evince a new function of SOX2OT as a participant of ER stress reprogramming of breast cancer cells.

Long non-coding RNA SOX2OT promotes the stemness phenotype of bladder cancer cells by modulating SOX2

BACKGROUND

Accumulating evidence indicates that long non-coding RNAs (lncRNAs) are potential biomarkers and key regulators of tumour development and progression. SOX2 overlapping transcript (SOX2OT) is a novel lncRNA that acts as a potential biomarker and is involved in the development of cancer and cancer stem cells. However, the clinical significance and molecular mechanism of SOX2OT in bladder cancer are still unknown.

METHODS

The expression level of SOX2OT was determined by RT-qPCR in a total of 106 patients with urothelial bladder cancer and in different bladder cancer cell (BCC) lines. Bladder cancer stem cells (BCSCs) were isolated from BCCs using flow cytometry based on the stem cell markers CD44 and ALDH1. Loss-of-function experiments were performed to investigate the biological roles of SOX2OT in the stemness phenotype of BCSCs. Comprehensive transcriptional analysis, RNA FISH, dual-luciferase reporter assays and western blots were performed to explore the molecular mechanisms underlying the functions of SOX2OT.

RESULTS

SOX2OT was highly expressed in bladder cancer, and increased SOX2OT expression was positively correlated with a high histological grade, advanced TNM stage and poor prognosis. Further experiments demonstrated that knockdown of SOX2OT inhibited the stemness phenotype of BCSCs. Moreover, inhibition of SOX2OT delayed xenograft tumour growth and decreased metastases in vivo. Mechanistically, we found that SOX2OT was mainly distributed in the cytoplasm and positively regulated SOX2 expression by sponging miR-200c. Furthermore, SOX2 overexpression reversed the SOX2OT silencing-induced inhibition of the BCSC stemness phenotype.

CONCLUSION

This study is the first to demonstrate that SOX2OT plays an important regulatory role in BCSCs and that SOX2OT may serve as a potential diagnostic biomarker and therapeutic target in bladder cancer.

Clinicopathological Implication of Long Non-Coding RNAs SOX2 Overlapping Transcript and Its Potential Target Gene Network in Various Cancers

Background

SOX2 overlapping transcript (SOX2-OT) produces alternatively spliced long non-coding RNAs (lncRNA). Previous studies of the prognostic role of SOX2-OT expression met with conflicting results. The aim of this study was to properly consider the prognostic role of SOX2-OT expression in several cancers. In addition, the regulative mechanism of SOX2-OT is explored.

Methods

PubMed, EMBASE, and Cochrane Library and The Cancer Genome Atlas (TCGA) database were comprehensively explored to recover pertinent studies. We conducted an extensive inquiry to verify the implication of SOX2-OT expression in cancer patients by conducting a meta-analysis of 13 selected studies. Thirty-two TCGA databases were used to analyze the connection between SOX2-OT expression and both the overall survival (OS) and clinicopathological characteristics of cancer patients using R and STATA 13.0. Trial sequential analysis (TSA) was adopted in order to compute the studies' power.

Results

Thirteen studies involving 1172 cancer patients and 32 TCGA cancer types involving 9676 cancer patients were eventually selected. Elevated SOX2-OT expression was significantly related to shorter OS (HR = 2.026, 95% CI: 1.691-2.428, P < 0.0001) and disease-free survival (DFS) (HR = 2.554, 95% CI: 1.261-5.174, P = 0.0092) in cancer patients. Meanwhile, TSA substantiated adequate power to demonstrate the relationship between SOX2-OT expression and OS. The cancer patients with elevated SOX2-OT expression were more likely to have advanced clinical stage (RR = 1.468, 95% CI: 1.106-1.949, P = 0.0079), earlier lymphatic metastasis (P = 0.0005), earlier distant metastasis (P < 0.0001), greater tumor size (P < 0.0001), and more extreme tumor invasion (P < 0.0001) compared to those with low SOX2-OT expression. Meta-regression and subgroup analysis revealed that follow-up time, sample type, and tumor type could significantly contribute to heterogeneity for survival outcomes. The follow-up time could significantly explain heterogeneity for tumor, node, metastasis (TNM) stage. Furthermore, up to 500 validated target genes were distinguished, and the gene oncology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses demonstrated that the validated targets of SOX2-OT were substantially enriched in cell adhesion, mRNA binding, and mRNA surveillance pathways.

Conclusions

Elevated expression of SOX2-OT predicted a poor OS and DFS. Overexpression of SOX2-OT was correlated with more advanced tumor stage, earlier lymphatic metastasis, earlier distant metastasis, larger tumor size, and deeper tumor invasion. SOX2-OT-mediated cell adhesion, mRNA binding, or mRNA surveillance could be intrinsic mechanisms for invasion and metastasis.

Long non-coding RNAs as the critical factors during tumor progressions among Iranian population: an overview

BACKGROUND

Cancer is associated with various genetic and environmental risk factors. Beside the mutations or aberrant expression of protein-coding genes, the genetic deregulation of non-coding RNAs has also an important role during tumor progression and metastasis. Long non-coding RNAs (lncRNAs) are a class of ncRNAs larger than 200 nucleotides that may function as tumor-suppressor or oncogene.

MAIN BODY

There is a raising trend of cancer incidence among Iranian population during the last decades. Therefore, it is required to prepare a general population specific panel of genetic markers for the early detection of cancer in this population. The tissue-specific expression characteristics and high stability in body fluids highlight the lncRNAs as efficient diagnostic and prognostic noninvasive biomarkers in cancer. In present review we summarized all of the lncRNAs which have been reported until now in different tumors among Iranian patients.

CONCLUSIONS

This review paves the way of introducing a population based noninvasive diagnostic panel of lncRNAs for the early detection of tumor cells among Iranian population.

Long noncoding RNA SOX2OT promotes the proliferation of pancreatic cancer by binding to FUS

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors has one of the worst prognoses, and the role of long noncoding RNAs (lncRNAs) in the biological and pathological processes of pancreatic cancer, including tumor cell proliferation, is a popular topic in tumor research. Our previous study revealed the correlation between high levels of the lncRNA-SOX2OT (SOX2OT) with poor survival outcomes. Cell Counting Kit-8, EdU, Flow cytometry and Colony formation assays as well as Xenograft growth of PDAC cells in mice were used for the detection of PDAC cells proliferation progression. Fluorescence in situ hybridization, RNA-binding protein pulldown and RNA immunoprecipitation assays were also used to identify the putative mechanisms of SOX2OT participating in the tumor progression. SOX2OT and its potential downstream targets were verified by Western blot and quantitative real-time polymerase chain reaction (qRT-PCR). SOX2OT was confirmed to promote the proliferation of PDAC cells. It was found to directly physically bind to FUS and we also demonstrated that FUS protein stability was affected by binding with SOX2OT and FUS could suppressed PDAC tumor by regulating cell cycle-associated factors CCND1 and p27. Our findings suggest that SOX2OT may act as a tumor promoter in PDAC through physically binding FUS and regulating its downstream cell cycle-associated factors CCND1 and p27. It may serve as an effective target for antitumor treatment for pancreatic cancer.

SOX2OT, a novel tumor-related long non-coding RNA

SOX2OT is a long non-coding RNA that is highly expressed in embryonic stem cells. The SOX2OT gene is comprised of 10 exons and more than two transcription start sites. Dysregulation of SOX2OT is observed in various tumors, including lung cancer, gastric cancer, esophageal cancer, breast cancer, hepatocellular carcinoma, ovarian cancer, pancreatic ductal adenocarcinoma, laryngeal squamous cell carcinoma, cholangiocarcinoma, osteosarcoma, nasopharyngeal carcinoma, and glioblastoma, wherein it typically functions as an oncogene and possibly as a tumor suppressor gene. The mechanisms underlying the effects of SOX2OT are complex and involve multiple factors and signaling pathways. In this review, we describe the current evidence regarding the role and potential clinical utility of SOX2OT in human cancers.

MTA3 Represses Cancer Stemness by Targeting the SOX2OT/SOX2 Axis

Cancer cell stemness (CCS) plays critical roles in both malignancy maintenance and metastasis, yet the underlying molecular mechanisms are far from complete. Although the importance of SOX2 in cancer development and CCS are well recognized, the role of MTA3 in these processes is unknown. In this study, we used esophageal squamous cell carcinoma (ESCC) as a model system to demonstrate that MTA3 can repress both CCS and metastasis in vitro and in vivo. Mechanistically, by forming a repressive complex with GATA3, MTA3 downregulates SOX2OT, subsequently suppresses the SOX2OT/SOX2 axis, and ultimately represses CCS and metastasis. More importantly, MTA3^low/SOX2^high is associated with poor prognosis and could serve as an independent prognostic factor. These findings altogether indicate that MTA3/SOX2OT/SOX2 axis plays an indispensable role in CCS. Therefore, this axis could be potentially used in cancer stratification and serves as a therapeutic target.

Invited Review: Long non-coding RNAs: important regulators in the development, function and disorders of the central nervous system

Genome-wide transcriptional studies have demonstrated that tens of thousands of long non-coding RNAs (lncRNA) genes are expressed in the central nervous system (CNS) and that they exhibit tissue- and cell-type specificity. Their regulated and dynamic expression and their co-expression with protein-coding gene neighbours have led to the study of the functions of lncRNAs in CNS development and disorders. In this review, we describe the general characteristics, localization and classification of lncRNAs. We also elucidate the examples of the molecular mechanisms of nuclear and cytoplasmic lncRNA actions in the CNS and discuss common experimental approaches used to identify and unveil the functions of lncRNAs. Additionally, we provide examples of lncRNA studies of cell differentiation and CNS disorders including CNS injuries and neurodegenerative diseases. Finally, we review novel lncRNA-based therapies. Overall, this review highlights the important biological roles of lncRNAs in CNS functions and disorders.

Genetic and molecular bases of esophageal Cancer among Iranians: an update

Abstract

Background

Esophageal cancer is one of the leading causes of cancer related deaths among the Iranians. There is still a high ratio of mortality and low 5 years survival which are related to the late onset and diagnosis. Majority of patients refer for the treatment in advanced stages of tumor progression.

Main body

It is required to define an efficient local panel of diagnostic and prognostic markers for the Iranians. Indeed such efficient specific panel of markers will pave the way to decrease the mortality rate and increase the 5 years survival among the Iranian patients via the early diagnosis and targeted therapy.

Conclusion

in present review we have reported all of the molecular markers in different signaling pathways and cellular processes which have been assessed among the Iranian esophageal cancer patients until now.

Identification of an Exosomal Long Noncoding RNA SOX2-OT in Plasma as a Promising Biomarker for Lung Squamous Cell Carcinoma

AIMS

Evaluation of nucleic acids in plasma exosomes is a noninvasive method that can be used to detect different types of cancer. The aim of this study was to determine the value of exosomal long noncoding RNAs (lncRNAs) in detecting lung squamous cell carcinoma (LSCC).

MATERIALS AND METHODS

A total of 75 LSCC patients and 79 negative control subjects were enrolled in the study. Twenty differentially expressed lncRNAs were evaluated as potential candidates. Exosomes were isolated by ultracentrifugation, and lncRNA levels in exosomes were determined using real-time polymerase chain reaction. Receiver Operating Characteristic (ROC) curves were used to determine specificity and sensitivity.

RESULTS

Exosomal SOX2-OT was significantly upregulated in LSCC patients and showed the strongest power in detecting LSCC. The area under the ROC curve was 0.815, and the sensitivity and specificity were 76% and 73.17%, respectively. Moreover, exosomal SOX2-OT levels were significantly correlated with tumor size, TNM stage, and lymph node metastasis. Exosomal SOX2-OT levels were significantly decreased in the postoperative plasma of LSCC patients.

CONCLUSION

SOX2-OT may serve as a promising noninvasive plasma-based tumor biomarker for LSCC.

Genome-wide analyses of long non-coding RNA expression profiles and functional network analysis in esophageal squamous cell carcinoma

Esophageal cancer (EC) is a serious malignancy and that is the fifth leading cause of cancer-related death worldwide. Esophageal squamous cell carcinoma (ESCC) is the main subtype of EC in China. In recent years, long non-coding RNAs (lncRNAs) have demonstrated to be novel tumor-associated regulatory factors. However, the functions and mechanisms of lncRNAs in ESCC have not been fully understood. In this study, we attempted to construct Genome-wide expression profiles of lncRNAs and their potential functions in ESCC. By using microarray, we found a total of 2,366 lncRNAs (1,032 upregulated and 1,334 downregulated) and 3,052 mRNAs (1,477 upregulated and 1,575 downregulated) were differentially expressed between the paired five ESCC tumor tissues and adjacent normal esophageal tissues (fold change, FC ≥2.0 or ≤0.5, p ≤ 0.05). Eight lncRNAs were detected by qRT-PCR to verify the results of the microarray, and the clinicopathological parameters were analyzed in 53 patients with ESCC. GO analysis and KEGG pathway analysis showed that the main biological functions of these abnormal lncRNAs were related to immune response, extracellular vesicular exosome, and protein binding. At the same time, the cis and trans models were used to analyze the potential synergistic regulatory relationship between lncRNAs and their potential target genes. Related genes were the processes that affect cell growth, differentiation, and migration. Then we mapped the lncRNAs-mRNAs co-expression pattern by calculating the PCCs of each lncRNA and mRNA expression value. Furthermore, we investigated the function and potential mechanism of a novel highly expressed lncRNA, lnc-KIAA1244-2, and found that its expression is associated with tumor size, N classification and clinical stage. Knockdown of lnc-KIAA1244-2 inhibited the cell proliferation and inhibited the TNFAIP3 expression in Eca-109 cells. Taken together, the expression patterns of lncRNAs and mRNAs in ESCC tumor tissues are different from those in normal adjacent tissues, and some abnormal expressed lncRNAs may play important roles in the development and progression of ESCC. Lnc-KIAA1244-2 could promote the cell proliferation of ESCC cells and might be a potent therapeutic target for ESCC.

lncRNAs combine and crosstalk with NSPc1 in ATRA-induced differentiation of U87 glioma cells

Nervous system polycomb 1 (NSPc1) is a member of the polycomb group (PcG) family of proteins and has been demonstrated to maintain the differentiation and pluripotency of stem cells. Long non-coding RNAs (lncRNAs) have been demonstrated to be involved in the control of pluripotency and differentiation in embryonic and pluripotent cells. In the present study, the expression levels of NSPc1 were associated with the malignant potential of various glioma cell lines. Additionally, lncRNAs were differentially expressed in glioblastoma cell lines. Following induced differentiation of U87 glioblastoma cells with all-trans retinoic acid, the expression levels of NSPc1 decreased initially, reaching its lowest point on day 6, but then subsequently increased until day 10. The expression of lncRNA candidates decreased in the cell differentiation stage. Additionally, the expression of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), sex-determining region of the Y chromosome-box 2 overlapping transcript (SOX2OT) and antisense non-coding RNA in the INK4 locus (ANRIL) was significantly altered relative to the expression levels of NSPc1. RNA immunoprecipitation (RIP) assays demonstrated that MALAT1, SOX2OT and ANRIL bind to NSPc1 in U87 glioblastoma cells and the enrichment of ANRIL in anti-NSPc1 antibody group was associated with the expression levels of NSPc1 during U87 cell differentiation. Small interfering RNA mediated downregulation of NSPc1 expression with MALAT1, SOX2OT and ANRIL, inhibited the proliferation, and promoted apoptosis in U87 cells. The results of the present study demonstrate that MALAT1, SOX2OT and ANRIL combine and crosstalk with NSPc1 in U87 cells to affect proliferation and apoptosis.

Plasma lncRNA expression profile as a prognostic tool in BRAF-mutant metastatic melanoma patients treated with BRAF inhibitor

Long non-coding RNAs (lncRNA) are dysregulated in many cancer types. Abnormal baseline levels of these lncRNAs display diagnostic and prognostic potential in cancer patients. The aim of this study was to evaluate the prognostic value of plasma lncRNAs in BRAF-mutant advanced melanoma patients treated with a BRAF inhibitor. Total RNA was isolated from plasma samples collected from 58 advanced BRAF-mutant melanoma patients and 15 healthy donors. The expression levels of 90 lncRNAs were estimated using the LncProfiler qPCR Array Kit (SBI) and LightCycler 96 (Roche). LncRNA expression levels correlated with responses to the BRAF inhibitor (vemurafenib) treatment. The patients were stratified into three groups based on their lncRNA levels with various lncRNA expressions (low, medium, and high). A Cox proportional hazards regression model was used to determine the lncRNAs that were significantly associated with both progression-free and overall survivals (PFS and OS, respectively) in patients receiving vemurafenib. The expression level of 12 lncRNAs was down-regulated, while five lncRNAs were up-regulated in melanoma patients compared to healthy donors. Kaplan-Meier analysis showed that upregulation or downregulation of 11 and 16 different lncRNAs were associated with longer median PFS and OS, respectively. Further analysis demonstrated that the baseline lncRNAs for IGF2AS, anti-Peg11, MEG3, Zeb2NAT are independent prognostic factors in BRAF-mutant advanced melanoma patients treated with vemurafenib. Evaluation of plasma lncRNAs expression level for advanced melanoma diagnosis and prognosis evaluation appears to be a safe and valuable method; however, this method requires further validation in larger cohorts and randomized trials.

Circulating long non-coding RNA GAS5 and SOX2OT as potential biomarkers for diagnosis and prognosis of non-small cell lung cancer

Early diagnosis of non-small cell lung cancer (NSCLC) is essential for patient treatment and prognosis. Long noncoding RNA (lncRNA) have potential roles in tumor initiation and differentiation. The objective of this study was to investigate whether the circulating lncRNA, growth arrest-specific transcript 5 (GAS5) and SOX2 overlapping transcript (SOX2OT), could be used as noninvasive biomarkers for NSCLC diagnosis. Moreover, we aimed at evaluating the association between lncRNA and the clinicopathological features of NSCLC in order to predict the cancer prognosis. The results showed significant downregulation of GAS5 expression and upregulation of SOX2OT in NSCLC patients compared with controls (P < 0.001). Furthermore, the expression level of GAS5 was declined in stage IV of NSCLC, but SOX2OT expression was increased sharply in stages III and IV. The expression levels of lncRNAs were used to distinguish NSCLC patients from control with an area under curve of 0.81 (sensitivity 82.5% and specificity 80%) for GAS5 and 0.73 (sensitivity 76.3% and specificity 78.6%) for SOX2OT. The combination of GAS5 and SOX2OT showed differentiation NSCLC patients from controls with increased sensitivity (83.8) and specificity (81.4). In conclusion, the newly developed diagnostic panel involving of circulating GAS5 and SOX2OT could be perfect biomarker for diagnosis and prognosis of NSCLC.

Comprehensive analysis of dysregulated lncRNAs, miRNAs and mRNAs with associated ceRNA network in esophageal squamous cell carcinoma

Mounting evidence suggests that long noncoding RNAs (lncRNAs) play an important role in tumor biology. To date, some lncRNAs have been found to be involved in competitive binding of miRNAs, a major group of competitive endogenous RNAs (ceRNAs), through participation in a regulatory network of protein-coding gene expression. However, the functional roles of lncRNA-mediated ceRNAs in esophageal squamous cell carcinoma (ESCC) have rarely been reported. Here, we construct a hypothetical ceRNA network by analyzing differential expression of lncRNAs, miRNAs and mRNAs obtained from 96 ESCC tissues and 13 normal tissues in the Cancer Genome Atlas. Ultimately, 95 lncRNAs, 9 miRNAs, and 40 mRNAs were identified (fold change >1.5, P < .05) and included in the ceRNA network for ESCC. Moreover, three lncRNAs (IGF2-AS, MUC2 and SOX2-OT) were found to be significantly associated with overall survival (log-rank test, P < .05), and further experiments revealed that lncRNA DLX6-AS1 knockdown inhibited the proliferation and invasion of esophageal cancer cells by enhancing the endogenous function of mTOR. We believe that the identified ceRNA network can facilitate a better understanding of lncRNA-related mechanisms in ESCC.

Differential expression of long non-coding RNA SOX2OT in gastric adenocarcinoma

BACKGROUND

Gastric cancer (GC) is the third leading cause of cancer-related death in the world. Dysfunction of long noncoding RNAs (lncRNAs) in cancers, especially those with role in pluripotency, are approved by increasing evidence.

OBJECTIVE

SOX2 overlapping transcript (SOX2OT) lncRNA, is aberrantly expressed in different cancers; however its role in gastric cancer is still controversial.

MATERIALS AND METHODS

In this study, the expression of SOX2OT was evaluated in 33 matched pair tumor and non-tumor gastric samples and AGS and MKN45 gastric and NTERA2 embryonic carcinoma cell lines by real time PCR.

RESULTS

Our finding revealed a significant decrease in the expression of SOX2OT in gastric tumor samples compared to their matched non-tumor samples (P= 0.05) and also a lower expression in high grade compared to low grade of gastric malignancy. As we expected SOX2OT expression showed higher expression in NT2 compared to AGS and MKN45 cell lines.

CONCLUSION

Simultaneous expression of SOX2 and SOX2OT was reported in some cancers. Regarding to the decreased expression of SOX2OT in the present study in concurrent with downregulation of SOX2 in our previous study, it seems that SOX2OT plays a tumor suppressor role in GC and may be useful biomarker for diagnosis of GC.