LncRNA TPT1-AS1 promotes tumorigenesis and metastasis in epithelial ovarian cancer by inducing TPT1 expression

Long non-coding RNA TPT1-AS1 inhibits ferroptosis in ovarian cancer by regulating GPX4 via CREB1 regulation

BACKGROUND

Long non-coding RNAs (lncRNAs) play crucial roles in cellular processes, with dysregulation implicated in various diseases, including cancers. The lncRNA TPT1-AS1 (TPT1 Antisense RNA 1) promotes tumor progression in several cancers, including ovarian cancer (OC), but its influence on ferroptosis and interaction with other proteins remains underexplored.

METHODS

In this study, we employed a multi-faceted approach to investigate the functional significance of TPT1-AS1 in OC. We assessed TPT1-AS1 expression in OC specimens and cell lines using RT-qPCR, in situ hybridization (ISH), and fluorescence in situ hybridization (FISH) assays. Functional assays included evaluating the impact of TPT1-AS1 knockdown on OC cell proliferation, migration, invasiveness, and cell cycle progression. Further, we explored and validated the interaction of TPT1-AS1 with other proteins using bioinformatics. Finally, we investigated TPT1-AS1 involvement in erastin-induced ferroptosis using Iron Assay, Malondialdehyde (MDA) assay, and reactive oxygen species (ROS) detection.

RESULTS

Our findings revealed that TPT1-AS1 overexpression in OC correlated with an unfavorable prognosis. TPT1-AS1 knockdown suppressed cell proliferation, migration, and invasiveness. Additionally, TPT1-AS1 inhibited erastin-induced ferroptosis, and in vivo experiments confirmed its oncogenic impact on tumor development. Mechanistically, TPT1-AS1 was found to regulate Glutathione Peroxidase 4 (GPX4) transcription via CREB1 (cAMP response element-binding protein 1) and interact with RNA-binding protein (RBP) KHDRBS3 (KH RNA Binding Domain Containing, Signal Transduction Associated 3) to regulate CREB1.

CONCLUSION

TPT1-AS1 promotes OC progression by inhibiting ferroptosis and upregulating CREB1, forming a regulatory axis with KHDRBS3. These findings highlight the regulatory network involving lncRNAs, RBPs, and transcription factors in cancer progression.

RAD51B-AS1 promotes the malignant biological behavior of ovarian cancer through upregulation of RAD51B

Long non-coding RNAs (lncRNAs) play an indispensable role in the occurrence and development of ovarian cancer (OC). However, the potential involvement of lncRNAs in the progression of OC is largely unknown. To investigate the detailed roles and mechanisms ofRAD51 homolog B-antisense 1 (RAD51B-AS1), a novel lncRNA in OC, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to verify the expression of RAD51B-AS1. Cellular proliferation, metastasis, and apoptosis were detected using the cell counting kit-8 (CCK-8), colony-formation, transwell, and flow cytometry assays. Mouse xenograft models were established for the detection of tumorigenesis. The results revealed that RAD51B-AS1 was significantly upregulated in a highly metastatic human OC cell line and OC tissues. RAD51B-AS1 significantly increased the proliferation and metastasis of OC cells and enhanced their resistance to anoikis. Biogenetics prediction analysis revealed that the only target gene of RAD51B-AS1 was RAD51B. Subsequent gene function experiments revealed that RAD51B exerts the same biological effects as RAD51B-AS1. Rescue experiments demonstrated that the malignant biological behaviors promoted by RAD51B-AS1 overexpression were partially or completely reversed by RAD51B silencing in vitro and in vivo. Thus, RAD51B-AS1 promotes the malignant biological behaviors of OC and activates the protein kinase B (Akt)/B cell lymphoma protein-2 (Bcl-2) signaling pathway, and these effects may be associated with the positive regulation of RAD51B expression. RAD51B-AS1 is expected to serve as a novel molecular biomarker for the diagnosis and prediction of poor prognosis in OC, and as a potential therapeutic target for disease management.

lncRNAs and cyclin-dependent kinases: Unveiling their critical roles in cancer progression

Long non-coding RNAs (lncRNAs) are a diverse class of RNA molecules that do not code for proteins but play critical roles in gene regulation. One such role involves the modulation of cell cycle progression and proliferation through interactions with cyclin-dependent kinases (CDKs), key regulators of cell division. Dysregulation of CDK activity is a hallmark of cancer, contributing to uncontrolled cell growth and tumor formation. These lncRNA-CDK interactions are part of a complex network of molecular mechanisms underlying cancer pathogenesis, involving various signaling pathways and regulatory circuits. Understanding the interplay between lncRNAs, CDKs, and cancer biology holds promise for developing novel therapeutic strategies targeting these molecular targets for more effective cancer treatment. Furthermore, targeting CDKs, key cell cycle progression and proliferation regulators, offers another avenue for disrupting cancer pathways and overcoming drug resistance. This can open new possibilities for individualized treatment plans and focused therapeutic interventions.

The lncRNA TPT1-AS1 promotes the survival of neuroendocrine prostate cancer cells by facilitating autophagy

The lncRNA tumor protein translationally controlled 1-antisense RNA 1 (TPT1-AS1) is known for its oncogenic role in various cancers, but its impact on the pathological progression of prostate cancer remains unclear. Our previous study demonstrated that the RE1-silencing transcription factor (REST) regulates neuroendocrine differentiation (NED) in prostate cancer (PCA) by derepressing specific long non-coding RNAs (lncRNAs), including TPT1-AS1. In this study, we revealed that TPT1-AS1 is overexpressed in LNCaP and C4-2B cells after IL-6 and enzalutamide treatment. By analyzing The Cancer Genome Atlas (TCGA) prostate adenocarcinoma dataset, we detected upregulated TPT1-AS1 expression in neuroendocrine-associated PCA but not in prostate adenocarcinoma. Single-cell RNA sequencing data further confirmed the increased TPT1-AS1 levels in neuroendocrine prostate cancer (NEPC) cells. Surprisingly, functional experiments indicated that TPT1-AS1 overexpression had no stimulatory effect on NED in LNCaP cells and that TPT1-AS1 knockdown did not inhibit IL-6-induced NED. Transcriptomic analysis revealed the essential role of TPT1-AS1 in synaptogenesis and autophagy activation in neuroendocrine differentiated PCA cells induced by IL-6 and enzalutamide treatment. TPT1-AS1 was found to regulate the expression of autophagy-related genes that maintain neuroendocrine cell survival through autophagy activation. In conclusion, our data expand the current knowledge of REST-repressed lncRNAs in NED in PCA and highlight the contribution of TPT1-AS1 to protect neuroendocrine cells from cell death rather than inducing NED. Our study suggested that TPT1-AS1 plays a cytoprotective role in NEPC cells; thus, targeting TPT1-AS1 is a potential therapeutic strategy.

The roles of long non-coding RNAs in ovarian cancer: from functions to therapeutic implications

Long non-coding RNAs (lncRNAs) are multifunctional and participate in a variety of biological processes and gene regulatory networks. The deregulation of lncRNAs has been extensively implicated in diverse human diseases, especially in cancers. Overwhelming evidence demonstrates that lncRNAs are essential to the pathophysiological processes of ovarian cancer (OC), acting as regulators involved in metastasis, cell death, chemoresistance, and tumor immunity. In this review, we illustrate the expanded functions of lncRNAs in the initiation and progression of OC and elaborate on the signaling pathways in which they pitch. Additionally, the potential clinical applications of lncRNAs as biomarkers in the diagnosis and treatment of OC were emphasized, cementing the bridge of communication between clinical practice and basic research.

IGF2 is upregulated by its antisense RNA to potentiate pancreatic cancer progression

Pancreatic cancer is a deadly cancer. More and more long noncoding RNAs (lncRNAs) have received confirmation to be dysregulated in tumors and exert the regulatory function. Studies have suggested that lncRNA insulin-like growth factor 2 antisense RNA (IGF2-AS) participates in the development of some cancers. Thus, we attempted to clarify its function in pancreatic cancer. Reverse-transcription quantitative polymerase chain reaction was applied for testing IGF2-AS expression in pancreatic cancer cells. Colony formation and Transwell wound experiments were applied for determining cell proliferative, migratory, and invasive capabilities. The alteration of epithelial-mesenchymal transition (EMT)-related gene level was tested via western blot. The mice model was established for measuring the tumor growth and metastasis. RIP validated the interaction of RNAs. IGF2-AS displays high expression in pancreatic cancer cells. IGF2-AS depletion repressed PC cell proliferative, migratory, invasive capabilities, and EMT process. Furthermore, pancreatic cancer tumor growth and metastasis were also inhibited by IGF2-AS depletion. Additionally, IGF2-AS positively regulated IGF2 level via recruiting HNRNPC. IGF2 overexpression counteracted the functions of IGF2-AS deficiency on pancreatic cancer cell behaviors. Moreover, IGF2R deletion was found to inhibit the positive effect of IGF2 on pancreatic cancer progression. IGF2-AS potentiates pancreatic cancer cell proliferation, tumor growth, and metastasis by recruiting HNRNPC via the IGF2-IGF2R regulatory pathway. These discoveries might offer a novel insight for treatment of PC, which may facilitate targeted therapies of PC in clinical practice.

Harnessing the value of TCTP in breast cancer treatment resistance: an opportunity for personalized therapy

Early identification of breast cancer (BC) patients at a high risk of progression may aid in therapeutic and prognostic aims. This is especially true for metastatic disease, which is responsible for most cancer-related deaths. Growing evidence indicates that the translationally controlled tumor protein (TCTP) may be a clinically relevant marker for identifying poorly differentiated aggressive BC tumors. TCTP is an intriguing protein with pleiotropic functions, which is involved in multiple signaling pathways. TCTP may also be involved in stress response, cell growth and proliferation-related processes, underlying its potential role in the initiation of metastatic growth. Thus, TCTP marks specific cancer cell sub-populations with pronounced stress adaptation, stem-like and immune-evasive properties. Therefore, we have shown that in vivo phospho-TCTP levels correlate with the response of BC cells to anti-HER2 agents. In this review, we discuss the clinical relevance of TCTP for personalized therapy, specific TCTP-targeting strategies, and currently available therapeutic agents. We propose TCTP as an actionable clinically relevant target that could potentially improve patient outcomes.

Identification of lncRNAs Deregulated in Epithelial Ovarian Cancer Based on a Gene Expression Profiling Meta-Analysis

Epithelial ovarian cancer (EOC) is one of the deadliest gynecological cancers worldwide, mainly because of its initially asymptomatic nature and consequently late diagnosis. Long non-coding RNAs (lncRNA) are non-coding transcripts of more than 200 nucleotides, whose deregulation is involved in pathologies such as EOC, and are therefore envisaged as future biomarkers. We present a meta-analysis of available gene expression profiling (microarray and RNA sequencing) studies from EOC patients to identify lncRNA genes with diagnostic and prognostic value. In this meta-analysis, we include 46 independent cohorts, along with available expression profiling data from EOC cell lines. Differential expression analyses were conducted to identify those lncRNAs that are deregulated in (i) EOC versus healthy ovary tissue, (ii) unfavorable versus more favorable prognosis, (iii) metastatic versus primary tumors, (iv) chemoresistant versus chemosensitive EOC, and (v) correlation to specific histological subtypes of EOC. From the results of this meta-analysis, we established a panel of lncRNAs that are highly correlated with EOC. The panel includes several lncRNAs that are already known and even functionally characterized in EOC, but also lncRNAs that have not been previously correlated with this cancer, and which are discussed in relation to their putative role in EOC and their potential use as clinically relevant tools.

The Roles of Antisense Long Noncoding RNAs in Tumorigenesis and Development through Cis-Regulation of Neighbouring Genes

Antisense long noncoding RNA (as-lncRNA) is a lncRNA transcribed in reverse orientation that is partially or completely complementary to the corresponding sense protein-coding or noncoding genes. As-lncRNAs, one of the natural antisense transcripts (NATs), can regulate the expression of their adjacent sense genes through a variety of mechanisms, affect the biological activities of cells, and further participate in the occurrence and development of a variety of tumours. This study explores the functional roles of as-lncRNAs, which can cis-regulate protein-coding sense genes, in tumour aetiology to understand the occurrence and development of malignant tumours in depth and provide a better theoretical basis for tumour therapy targeting lncRNAs.

Clinicopathological and prognostic value of lncRNA TPT1-AS1 in cancer: a systematic review study and meta-analysis

INTRODUCTION

Aberrant expression of lncRNAs in cancer cells can impact their key phenotypes. We aimed to summarize available evidence on clinicopathological and prognostic value of lncRNA TPT1-AS1 in cancer.

METHODS

A systematic search was performed on Medline and Embase databases using relevant key terms covering lncRNA TPT1-AS1, cancer, and clinical outcomes. The effect size estimates and their 95 % confidence interval (CI) were pooled using random-effects models. Meta- analyses were conducted using STATA 16.0 software.

RESULTS

Seventeen articles met our eligibility criteria. Tumor tissue compared to normal tissue showed increased level of lncRNA TPT1-AS1 expression (pooled standardized mean difference (95 % CI): 0.65 (0.52-0.79)). Overexpression of this lncRNA was a significant predictor for poor prognosis (Pooled log-rank test P-value < 0.001); in patients with high-level of lncRNA TPT1-AS1, the risk of death at five years was 1.40 times greater than their counterparts. The pooled Odds ratios for association lncRNA TPT1-AS1 with tumor stage, tumor size, and lymph node metastasis were 1.94 (95 % CI: 0.90-4.19, 8 studies, I² = 79.6 %), 2.33 (95 % CI: 1.31-4.14, 5 studies, I² = 40.0 %), and 1.89 (95 % CI: 1.08-3.36, 5 studies, I² = 61.7 %), respectively. Regarding the identified potential mechanisms, lncRNA TPT1-AS1 plays a role in cancer growth mainly by sponging miRNAs and regulating their downstream targets or controlling the expression of key cell cycle regulators.

CONCLUSION

In cancer patients, elevated expression of lncRNA TPT1-AS1 might be associated with a shorter Overall Survival, advanced stages, larger tumor size, and lymph node metastasis.

lncRNA TPT1-AS1 promotes cell migration and invasion in esophageal squamous-cell carcinomas by regulating the miR-26a/HMGA1 axis

lncRNA TPT1-AS1 plays an oncogenic role in ovarian and cervical cancers. However, its involvement in the pathological progress of esophageal squamous-cell carcinomas (ESCCs) is unclear. lncRNA TPT1-AS1 was mainly localized in the cytoplasm of ESCC cells and interacted with miR-26a. In ESCC tissues, lncRNA TPT1-AS1 level was obviously increased, while miR-26a level was decreased. Interestingly, lncRNA TPT1-AS1 level was not significantly correlated with miR-26a level but was positively correlated with HMGA1 mRNA, a target of miR-26a. In ESCC cell lines KYSE510 and KYSE-30, lncRNA TPT1-AS1 overexpression enhanced HMGA1 expression, while it had no effect on miR-26a expression. Cell migration and proliferation assays indicated that lncRNA TPT1-AS1 and HMGA1 overexpression promoted ESCC cell migration and invasion, while their effects were alleviated by miR-26a overexpression. The migration and invasion of ESCC cells were suppressed by lncRNA TPT1-AS1 knockdown. In conclusion, lncRNA TPT1-AS1 plays an oncogenic role in ESCC and might function by upregulating HMGA1 via sponging miR-26a.

A review of literature: role of long noncoding RNA TPT1-AS1 in human diseases

Human diseases are multifactorial processes mainly driven by the intricate interactions of genetic and environmental factors. Long noncoding RNAs (lncRNAs) represent a type of non-coding RNAs with more than 200 nucleotides. Multiple studies have demonstrated that the dysregulation of lncRNAs is associated with complex biological as well as pathological processes through various mechanism, especially the regulation of gene transcription and related signal transduction pathways. Moreover, an increasing number of studies have explored lncRNA-based clinical applications in different diseases. For instance, the lncRNA Tumor Protein Translationally Controlled 1 (TPT1) Antisense RNA 1 (TPT1-AS1) was found to be dysregulated in several types of disease and strongly associated with patient prognosis and diverse clinical features. Recent studies have also documented that TPT1-AS1 modulates numerous biological processes through multiple mechanisms, including cell proliferation, apoptosis, autophagy, invasion, migration, radiosensitivity, chemosensitivity, stemness, and extracellular matrix (ECM) synthesis. Furthermore, TPT1-AS1 was regarded as a promising biomarker for the diagnosis, prognosis and treatment of several human diseases. In this review, we summarize the role of TPT1-AS1 in human diseases with the aspects of its expression, relevant clinical characteristics, molecular mechanisms, biological functions, and subsequent clinical applications.

LINC02535/miR-30a-5p/GALNT3 axis contributes to lung adenocarcinoma progression via the NF- κ B signaling pathway

Long non-coding RNAs (LncRNA) play important roles in multiple types of cancers. We addressed the role of LINC02535 by regulating the miR-30a-5p /GalNAc Transferase 3 (GALNT3) axis to promote the proliferation, migration, and invasion in lung adenocarcinoma (LUAD) cells. The Cancer Genome Atlas (TCGA) database screened differentially expressed lncRNAs. Quantitative real-time PCR analysis (qRT-PCR) confirmed that LINC02535 is highly expressed in LUAD tissues and cells. In vitro experiments showed that LINC02535 promotes the proliferation, migration, and invasion of LUAD cells. A xenograft mouse model was used to show that LINC02535 promotes tumor growth in vivo. RNA immunoprecipitation (RIP) and Dual-luciferase reporter assay results confirmed that LINC02535 targets miR-30a-5p. The Vicia villosa lectin (VVA) pull-down assay indicated that MUC1 is the glycosylation target of GALNT3, and western blot verified that NF-κB is the downstream signaling pathway of MUC1. We found that LINC02535 was increased in LUAD tissues and cells, and LINC02535 was correlated with the poor prognosis of LUAD patients. miR-30a-5p acts as a tumor suppressor in LUAD by targeting GALNT3. We also demonstrated that LINC02535 might function as the sponge of miR-30a-5p to up-regulate GALNT3, and consequently promote the proliferation and metastasis of LUAD. LINC02535 acts as a competing endogenous RNA (ceRNA) to interact with miR-30a-5p, thereby upregulating the expression of GALNT3, enhancing the function of MUC1, and activating the NF-κB signaling pathway, promoting the malignant progression of LUAD cells.Abbreviations: LncRNA:long non-coding RNA; LUAD: lung adenocarcinoma; TCGA: The Cancer Genome Atlas; GALNT3: GalNAc Transferase 3; qRT-PCR: quantitative real-time PCR analysis; RIP: RNA immunoprecipitation; SPF: specific pathogen-free; VVA: Vicia villosa lectin; ceRNA: competing endogenous RNA; MiRNAs: microRNAs; FBS: fetal bovine serum; PBS: Phosphate buffered saline; CCK-8: Cell Counting Kit-8; NSCLC: non-small cell lung cancer; OC: ovarian cancer; HCC: hepatocellular carcinoma.

LncRNA IGF2-AS promotes endometriosis progression through targeting miR-370-3p/IGF2 axis and activating PI3K/AKT/mTOR signaling pathway

PURPOSE

Endometriosis, a gynecological disease, is difficult to be cured. Currently, to identify more potential biomarkers for the early diagnosis of endometriosis is urgently needed. Insulin like growth factor 2 (IGF2) has been revealed to correlate with endometriosis. This research aimed to further explore the role of IGF2 and its up-stream mechanism in endometriosis.

METHODS

Primary ectopic endometrial stromal cells (EESCs) were extracted from ectopic endometrial tissues which were pathological endometrial tissues resected from three patients with II-III endometriosis. Primary normal endometrial stromal cells (NESCs) were extracted from normal endometrial tissues of two patients with grade III cervical dysplasia and one patient with uterine leiomyoma III. Four endometriotic cell lines (EEC145T, hEM15A, hEM5B2, and 12Z) and normal human endometrial epithelial cells (hEECs) were purchased. Cell proliferation, migration, and invasion were evaluated through functional assays. The molecular interaction between RNAs was investigated through mechanistic analyses.

RESULTS

We discovered that IGF2 was upregulated in purchased endometriotic cells and primary EESC. Suppression of IGF2 hampered cell proliferation, migration, and invasion. Furthermore, insulin-like growth factor 2 antisense RNA (IGF2-AS) was uncovered to positively regulate IGF2 expression and enhanced proliferative, migratory, and invasive abilities of endometriotic cells. Mechanistically, miR-370-3p was found to bind with IGF2-AS and IGF2. IGF2-AS competitively bind with miR-370-3p to upregulate IGF2. Furthermore, IGF2-AS was revealed to activate the PI3K/AKT/mTOR signaling pathway through targeting miR-370-3p/IGF2 axis.

CONCLUSION

IGF2-AS promotes endometriotic cell growth via regulating IGF2/miR-370-3p axis and further activating PI3K/AKT/mTOR signaling pathway.

LncRNA NORAD accelerates the progression of non-small cell lung cancer via targeting miRNA-455/CDK14 axis

BACKGROUND

To explore the potential involvement of long non-coding RNA (lncRNA) NORAD in regulating the progression of Non-small cell lung cancer (NSCLC), and its possible mechanism.

METHODS

Relative level of NORAD in NSCLC tissues and cell lines was determined. Its level in NSCLC patients with different tumor staging (T1-T2, T3-T4) and either with lymphatic metastasis or not was examined as well. Kaplan-Meier curves were depicted for assessing the prognostic value of NORAD in NSCLC. Regulatory effects of NORAD on the proliferative ability of NCI-H1650 and HCC827 cells were evaluated. Dual-luciferase reporter gene assay was conducted to identify the binding between NORAD and miRNA-455, as well as between miRNA-455 and CDK14. At last, the role of NORAD/miRNA-455/CDK14 regulatory loop in influencing the progression of NSCLC was determined.

RESULTS

NORAD was upregulated in NSCLC tissues and cells. Its level was higher in NSCLC patients with advanced stage or accompanied with lymphatic metastasis. Worse prognosis was observed in NSCLC patients presenting high level of NORAD. Silence of NORAD attenuated the proliferative ability of NCI-H1650 and HCC827 cells. MiRNA-455 was the downstream target binding to NORAD. Its level was negatively regulated by NORAD. Knockdown of miRNA-455 could reverse the role of NORAD in regulating the proliferative ability of NSCLC. Moreover, CDK14 was the target gene of miRNA-455. CDK14 level was negatively regulated by miRNA-455.

CONCLUSIONS

LncRNA NORAD is upregulated in NSCLC, which enhances the proliferative ability of tumor cells by targeting miRNA-455/CDK14 axis and thereby accelerates the progression of NSCLC.

Unveiling caspase-2 regulation by non-coding RNAs

Non-coding RNAs (ncRNAs) are a group of RNA molecules, such as small nucleolar RNAs, circular RNAs (circRNAs), microRNAs (miRNAs) and long-noncoding RNAs (ncRNAs), that do not encode proteins. Although their biofunctions are not well-understood, many regulatory ncRNAs appear to be highly involved in regulating the transcription and translation of several genes that have essential biological roles including cell differentiation, cell death, metabolism, tumorigenesis and so on. A growing number of studies have revealed the associations between dysregulated ncRNAs and caspases involved in cell death in numerous human diseases. As one of the initiator and executor caspases, caspase-2 is the most evolutionally conserved caspase in mammals, exerting both apoptotic and non-apoptotic functions. A great deal of studies has shown the involvement of caspase-2 as a tumor suppressor in multiple oncogene-driven cancers, and yet a comprehensive understanding of its biological roles remains largely unknown. In this review, we highlight a compilation of studies focused on the interaction between caspase-2 and miRNAs/lncRNAs in the context of different diseases in order to deepen our knowledge on the regulatory biofunctions of caspase-2 and, furthermore, provide more insight into understanding the role that ncRNAs/caspase-2 axis plays in the development of human diseases.

Positive feedback regulation of lncRNA TPT1-AS1 and ITGB3 promotes cell growth and metastasis in pancreatic cancer

Emerging evidence has indicated that long noncoding RNAs (lncRNAs) are potential biomarkers and play crucial roles in cancer development. However, the functions and underlying mechanisms of lncRNA TPT1-AS1 in pancreatic ductal adenocarcinoma (PDAC) remain elusive. RNAseq data of PDAC tissues and normal tissues were analyzed, and lncRNAs which were associated with PDAC prognosis were identified. The clinical relevance of TPT1-AS1 for PDAC patients was explored, and the effects of TPT1-AS1 in PDAC progression were investigated in vitro and in vivo. LncRNA TPT1-AS1 was highly expressed in PDAC, and high TPT1-AS1 levels predicted a poor prognosis. Moreover, functional experiments revealed that TPT1-AS1 promoted pancreatic cancer cell proliferation, migration, invasion, and epithelial-to-mesenchymal transition (EMT) process in vitro and in vivo. Mechanistically, TPT1-AS1 functioned as an endogenous sponge for miR-30a-5p, which increased integrin β3 (ITGB3) level in pancreatic cancer cells. Conversely, our data revealed that ITGB3 could activate the transcription factor signal transducer and activator of transcription 3 (STAT3), which in turn bound directly to the TPT1-AS1 promoter and affected the expression of TPT1-AS1, thus forming a positive feedback loop with TPT1-AS1. Taken together, our results uncovered a reciprocal loop of TPT1-AS1 and ITGB3 which contributed to pancreatic cancer growth and development, and indicated that TPT1-AS1 might serve as a novel potential diagnostic biomarker and therapeutic target for PDAC patients.

Emerging Roles and Mechanisms of lncRNA FOXD3-AS1 in Human Diseases

Numerous long noncoding RNAs (lncRNAs) have been identified as powerful regulators of human diseases. The lncRNA FOXD3-AS1 is a novel lncRNA that was recently shown to exert imperative roles in the initialization and progression of several diseases. Emerging studies have shown aberrant expression of FOXD3-AS1 and close correlation with pathophysiological traits of numerous diseases, particularly cancers. More importantly, FOXD3-AS1 was also found to ubiquitously impact a range of biological functions. This study aims to summarize the expression, associated clinicopathological features, major functions and molecular mechanisms of FOXD3-AS1 in human diseases and to explore its possible clinical applications.

Long Non-coding RNA TPT1-AS1 Suppresses APC Transcription in a STAT1-Dependent Manner to Increase the Stemness of Colorectal Cancer Stem Cells

Cancer stem cells (CSCs) are the major culprits leading to a new level of complexity and the consequential therapy resistance and disease recurrence in colorectal cancer (CRC). This study focuses on the effect of long non-coding RNA (lncRNA) TPT1-AS1 and its associated molecules on the stemness maintenance of CRC stem cells. TPT1-AS1 was identified as a significantly upregulated gene in CRC using the GSE146587 dataset. Stem cells from CRC HCT116 and CACO2 cells were isolated. TPT1-AS1 was significantly highly expressed in the CSCs compared to non-stem cells. Downregulation of TPT1-AS1 reduced the stemness of the CRC stem cells. TPT1-AS1 recruited STAT1 to the promoter region of APC to suppress APC transcription. Further upregulation of STAT1 or downregulation of APC blocked the role of TPT1-AS1 silencing and restored the malignant behaviors of CSC stem cells. APC inactivated the Wnt/β-catenin pathway. Overexpression of STAT1 restored the levels of cyclin D1 and β-catenin in cells suppressed by TPT1-AS1 silencing. In summary, this work demonstrates that TPT1-AS1 recruits STAT1 to suppress APC transcription and increase the stemness of colorectal CSCs via Wnt/β-catenin activation.

LINC00974 sponges miR-33a to facilitate cell proliferation, invasion, and EMT of ovarian cancer through HMGB2 upregulation

The function and mechanism of long intergenic non-protein coding RNA 974 (LINC00974) are rarely reported in ovarian cancer (OC). The study aimed to investigate how LINC00974 affects the progression of OC. The expression levels of LINC00974, microRNA-33a (miR-33a), and high mobility group box 2 (HMGB2) mRNA were detected by qRT-PCR. The LINC00974/miR-33a/HMGB2 axis was confirmed by dual-luciferase reporter, RNA-binding protein immunoprecipitation (RIP), and biotinylated RNA pull-down assays. A series of in vitro experiments were employed to assess the effects of LINC00974/miR-33a/HMGB2 axis on the proliferation, invasion and epithelial mesenchymal transition (EMT) of OC cells. Results showed that LINC00974 and HMGB2 mRNA expression were upregulated in OC cells, while miR-33a expression was downregulated. HMGB2 was a direct target gene of miR-33a. LINC00974 act as a competing endogenous RNA (ceRNA) to directly bind with miR-33a, thereby upregulated HMGB2 expression. Notably, silencing of LINC00974 suppressed cell proliferation, invasion and EMT of OC cells, whereas miR-33a knockdown partially reversed the phenotypes of LINC00974 on OC cells. Overall, our study demonstrated that LINC00974 sponges miR-33a to promote cell proliferation, invasion, and EMT of OC through HMGB2 upregulation. LINC00974/miR-33a/HMGB2 axis may be an important signaling pathway in the progression of OC.

Identification and validation of a five-lncRNA signature for predicting survival with targeted drug candidates in ovarian cancer

The dysregulation of long non-coding RNAs (lncRNAs) plays a crucial role in ovarian cancer (OC). In this study, we screened out five differentially expressed lncRNAs (AC092718.4, AC138035.1, BMPR1B-DT, RNF157-AS1, and TPT1-AS1) between OC and normal ovarian based on TCGA and GTEx RNA-seq databases by using Kaplan-Meier analysis and univariate Cox, LASSO, and multivariate Cox regression. Then, a risk signature was constructed, with 1, 3, 5-year survival prediction accuracy confirmed by ROC curves, and an online survival calculator for easier clinical use. With lncRNA-microRNA-mRNA regulatory networks established, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed, suggesting the involvement of a variety of cancer-related functions and pathways. Finally, five candidate small-molecule drugs (thioridazine, trifluoperazine, loperamide, LY294002, and puromycin) were predicted by Connectivity Map. In conclusion, we identified a 5-lncRNA signature of prognostic value with its ceRNA networks, and five candidate drugs against OC.[Figure: see text].

(In)Distinctive Role of Long Non-Coding RNAs in Common and Rare Ovarian Cancers

Rare ovarian cancers (ROCs) are OCs with an annual incidence of fewer than 6 cases per 100,000 women. They affect women of all ages, but due to their low incidence and the potential clinical inexperience in management, there can be a delay in diagnosis, leading to a poor prognosis. The underlying causes for these tumors are varied, but generally, the tumors arise due to alterations in gene/protein expression in cellular processes that regulate normal proliferation and its checkpoints. Dysregulation of the cellular processes that lead to cancer includes gene mutations, epimutations, non-coding RNA (ncRNA) regulation, posttranscriptional and posttranslational modifications. Long non-coding RNA (lncRNA) are defined as transcribed RNA molecules, more than 200 nucleotides in length which are not translated into proteins. They regulate gene expression through several mechanisms and therefore add another level of complexity to the regulatory mechanisms affecting tumor development. Since few studies have been performed on ROCs, in this review we summarize the mechanisms of action of lncRNA in OC, with an emphasis on ROCs.

Transcriptional alterations of protein coding and noncoding RNAs in triple negative breast cancer in response to DNA methyltransferases inhibition

Background

DNA methylation plays a crucial role in multiple cellular processes such as gene regulation, chromatin stability, and genetic imprinting. In mammals, DNA methylation is achieved by DNA methyltransferases (DNMTs). A number of studies have associated alterations in DNMT activity to tumorigenesis; however, the exact role of DNMTs in shaping the genome in triple negative breast cancer (TNBC) is still being unraveled.

Methods

In the current study, we employed two DNMT inhibitors (Decitabine and 5-Azacytidine), two TNBC models (MDA-MB-231 and BT-549) and whole transcriptome RNA-Seq and characterized the transcriptional alterations associated with DNMT inhibition. Colony forming unit (CFU), flow cytometry, and fluorescent microscopy were used to assess cell proliferation, cell cycle distribution, and cell death, respectively. Ingenuity pathway analysis (IPA) was used for network and pathway analyses.

Results

Remarkably, DNMT inhibition induced the expression of genes involved in endoplasmic reticulum response to stress, response to unfolder protein, as well as cobalamin metabolic processes. In contrast, suppression of cellular processes related to cell cycle and mitosis were hallmarks of DNMT inhibition. Concordantly, DNMT inhibition led to significant inhibition of TNBC cell proliferation, G2-M cell cycle arrest and induction of cell death. Mechanistically, DNMT inhibition activated TP53, NUPR1, and NFkB (complex) networks, while RARA, RABL6, ESR1, FOXM1, and ERBB2 networks were suppressed. Our data also identified the long noncoding RNA (lncRNA) transcriptional portrait associated with DNMT inhibition and identified 25 commonly upregulated and 60 commonly downregulated lncRNAs in response to Decitabine and 5-Azacytidinec treatment in both TNBC models. TPT1-AS1 was the most highly induced (6.3 FC), while MALAT1 was the most highly suppressed (− 7.0 FC) lncRNA in response to DNMT inhibition.

Conclusions

Taken together, our data provides a comprehensive view of transcriptome alterations in the coding and noncoding transcriptome in TNBC in response to DNMT inhibition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02213-2.

lncRNA TPT1‑AS1 knockdown inhibits liver cancer cell proliferation, migration and invasion

Long non-coding RNA (lncRNA) tumor protein translationally controlled 1 antisense RNA 1 (TPT1-AS1) serves as an oncogene in several tumors, including ovarian and cervical cancer. However, the functional role of TPT1-AS1 in liver cancer (LC) is not completely understood. The present study aimed to explore the role of TPT1-AS1 in LC. In this study, the reverse transcription-quantitative PCR results demonstrated that TPT1-AS1 expression was significantly upregulated in LC tissues and cell lines compared with adjacent paracancerous tissues and THLE-3 cells, respectively. Elevated TPT1-AS1 expression was significantly associated with TNM stage lymph node metastasis and poor prognosis in patients with LC, as determined via χ² and Kaplan-Meier survival analyses. By constructing TPT1-AS1 knockdown LC cell lines (HepG2 and SNU-182), loss-of-function experiments, including Cell Counting Kit-8, colony formation, flow cytometry, wound healing and Transwell assays, were performed to explore the function role of TPT1-AS1 in LC in vitro. The results demonstrated that TPT1-AS1 knockdown inhibited LC cell proliferation, G₁/S transition, migration and invasion compared with the small interfering RNA (si)-negative control (NC) group. Mechanistically, TPT1-AS1 knockdown markedly decreased CDK4, N-cadherin and Vimentin expression levels, but notably increased p21 and E-cadherin expression levels compared with the si-NC group. Therefore, the results of the present study suggested that TPT1-AS1 might serve as a promising therapeutic target for LC treatment.

LINC00852 promotes the proliferation and invasion of ovarian cancer cells by competitively binding with miR-140-3p to regulate AGTR1 expression

Background

Dysregulation of long non-coding RNAs (lncRNAs) has been identified in ovarian cancer. However, the expression and biological functions of LINC00852 in ovarian cancer are not understood.

Methods

The expressions of LINC00852, miR-140-3p and AGTR1 mRNA in ovarian cancer tissues and cells were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay. Gain- and loss-of-function assays were performed to explore the biological functions of LINC00852 and miR-140-3p in the progression of ovarian cancer in vitro. The bindings between LINC00852 and miR-140-3p were confirmed by luciferase reporter gene assay, RNA immunoprecipitation (RIP) assay and RNA pull-down assay.

Results

We found that LINC00852 expression was significantly up-regulated in ovarian cancer tissues and cells, whereas miR-140-3p expression was significantly down-regulated in ovarian cancer tissues. Functionally, LINC00852 knockdown inhibited the viability, proliferation and invasion of ovarian cancer cells, and promoted the apoptosis of ovarian cancer cells. Further investigation showed that LINC00852 interacted with miR-140-3p, and miR-140-3p overexpression suppressed the viability, proliferation and invasion of ovarian cancer cells. In addition, miR-140-3p interacted with AGTR1 and negatively regulated its level in ovarian cancer cells. Mechanistically, we found that LINC00852 acted as a ceRNA of miR-140-3p to promote AGTR1 expression and activate MEK/ERK/STAT3 pathway. Finally, LINC00852 knockdown inhibited the growth and invasion ovarian cancer in vivo.

Conclusion

LINC00852/miR-140-3p/AGTR1 is an important pathway to promote the proliferation and invasion of ovarian cancer.

Keep your eyes peeled for long noncoding RNAs: Explaining their boundless role in cancer metastasis, drug resistance, and clinical application

Cancer metastasis and drug resistance are two major obstacles in the treatment of cancer and therefore, the leading cause of cancer-associated mortalities worldwide. Hence, an in-depth understanding of these processes and identification of the underlying key players could help design a better therapeutic regimen to treat cancer. Earlier thought to be merely transcriptional junk and having passive or secondary function, recent advances in the genomic research have unravelled that long noncoding RNAs (lncRNAs) play pivotal roles in diverse physiological as well as pathological processes including cancer metastasis and drug resistance. LncRNAs can regulate various steps of the complex metastatic cascade such as epithelial-mesenchymal transition (EMT), invasion, migration and metastatic colonization, and also affect the sensitivity of cancer cells to various chemotherapeutic drugs. A substantial body of literature for more than a decade of research evince that lncRNAs can regulate gene expression at different levels such as epigenetic, transcriptional, posttranscriptional, translational and posttranslational levels, depending on their subcellular localization and through their ability to interact with DNA, RNA and proteins. In this review, we mainly focus on how lncRNAs affect cancer metastasis by modulating expression of key metastasis-associated genes at various levels of gene regulation. We also discuss how lncRNAs confer cancer cells either sensitivity or resistance to various chemo-therapeutic drugs via different mechanisms. Finally, we highlight the immense potential of lncRNAs as prognostic and diagnostic biomarkers as well as therapeutic targets in cancer.

Silencing of the long noncoding RNA LINC01132 alleviates the oncogenicity of epithelial ovarian cancer by regulating the microRNA‑431‑5p/SOX9 axis

To date, the role of lncRNA long intergenic non‑protein‑coding RNA 1132 (LINC01132) expression in epithelial ovarian cancer (EOC) has not been explored. Thus, LINC01132 expression in EOC was assessed and the regulatory activity of LINC01132 on the malignant behaviours of EOC cells was investigated. Additionally, the molecular events that occurred downstream of LINC01132 in EOC cells were also revealed. In the present study, LINC01132 expression in EOC was verified by employing RT‑qPCR. The effects of LINC01132 on the aggressive behaviours of EOC cells were revealed utilizing multiple functional experiments. The targeting interaction among LINC01132, microRNA‑431‑5p (miR‑431‑5p) and SRY‑box 9 (SOX9) was demonstrated by RNA immunoprecipitation and luciferase reporter assay. Herein, LINC01132 was overexpressed in EOC and was significantly associated with poor patient prognosis. Functionally, cell experiments revealed that LINC01132 depletion produced cancer‑suppressive effects in EOC cells and regulated cell proliferation, migration, invasion and apoptosis in vitro. Additionally, the loss of LINC01132 attenuated tumour growth in vivo. Mechanistically, LINC01132 acted as a competing endogenous RNA by sequestering miR‑431‑5p and consequently overexpressing SOX9 in EOC cells, forming a LINC01132/miR‑431‑5p/SOX9 axis. In rescue experiments, miR‑431‑5p inhibition or SOX9 reintroduction eliminated the anti‑tumour effects of LINC01132 silencing on the pathological behaviours of EOC cells. Generally, LINC01132 exhibited oncogenic activities in EOC cells by regulating the outcome of the miR‑431‑5p/SOX9 axis, providing an effective target for EOC diagnosis, therapy and prognosis evaluation.

Long non-coding RNA TPT1-AS1 sensitizes breast cancer cell to paclitaxel and inhibits cell proliferation by miR-3156-5p/caspase 2 axis

Long non-coding RNAs (lncRNAs) are key modulators during cancer progression. Application of using lncRNA expression to evaluate patient prognosis and sensitivity to treatment is highly anticipated, yet the expression and mechanism of many lncRNAs remain unknown. Herein, we projected for the investigation of TPT1-AS1 function in breast cancer. TPT1-AS1 was assessed by bioinformatic analysis of publicly available datasets and quantitative real-time PCR (qRT-PCR). Cell sensitivity to paclitaxel and cell proliferation was measured by flow cytometry and CCK-8. Interaction among TPT1-AS1, microRNA (miRNA, miR)-3156-5p and Caspase 2 (CASP2) was studied by bioinformatic analysis, qRT-PCR, western blot as well as dual luciferase reporter assay. Herein, TPT1-AS1 was significantly diminished in breast cancer from publicly available datasets and our collected samples. In breast cancer cells, TPT1-AS1 overexpression repressed cell proliferation and sensitized breast cancer cells to paclitaxel. RegRNA 2.0 predicted a potential interaction between TPT1-AS1 and miR-3156-5p which was confirmed by qRT-PCR as well as dual luciferase reporter assay. CASP2, a proapoptotic gene, was corroborated to be targeted by miR-3156-5p. Meanwhile, TPT1-AS1 upregulated CASP2 in breast cancer cells, and its biological function was reversed by CASP2 knockdown. Collectively, TPT1-AS1 diminished cell proliferation and sensitized cells to chemotherapy by sponging miR-3156-5p and upregulating CASP2, acting as a biomarker for patients with breast cancer.

Non-Coding RNAs as Biomarkers of Tumor Progression and Metastatic Spread in Epithelial Ovarian Cancer

Simple Summary

Despite advances in cancer research in recent years, efficient predictive biomarkers of tumor progression and metastatic spread for ovarian cancer are still missing. Therefore, we critically address recent findings in the field of non-coding RNAs (microRNAs and long non-coding RNAs) and DNA methylation in ovarian cancer patients as promising novel biomarkers of ovarian cancer progression.

Abstract

Ovarian cancer is one of the most common causes of death among gynecological malignancies. Molecular changes occurring in the primary tumor lead to metastatic spread into the peritoneum and the formation of distant metastases. Identification of these changes helps to reveal the nature of metastases development and decipher early biomarkers of prognosis and disease progression. Comparing differences in gene expression profiles between primary tumors and metastases, together with disclosing their epigenetic regulation, provides interesting associations with progression and metastasizing. Regulatory elements from the non-coding RNA families such as microRNAs and long non-coding RNAs seem to participate in these processes and represent potential molecular biomarkers of patient prognosis. Progress in therapy individualization and its proper targeting also rely upon a better understanding of interactions among the above-listed factors. This review aims to summarize currently available findings of microRNAs and long non-coding RNAs linked with tumor progression and metastatic process in ovarian cancer. These biomolecules provide promising tools for monitoring the patient’s response to treatment, and further they serve as potential therapeutic targets of this deadly disease.

Knockdown of long non-coding RNA TPT1-AS1 inhibits invasion and migration of hepatocarcinoma cells

BACKGROUND

The long non-coding RNA (lncRNA) TPT1-AS1 has been proved to affect the migration and invasion of tumor cells by different means, but its specific role and related mechanisms in hepatic carcinoma still need further research.

AIM

To investigate the expression of TPT1-AS1 in hepatocarcinoma tissues and cell lines and explore its biological role in the invasion and migration of hepatocarcinoma cells.

METHODS

Real-time quantitative PCR was used to measure lncRNA TPT1-AS1 expression in hepatocarcinoma tissue and cell lines (Huh7, SMMC-7721, HCCLM3, and HepG2). After being transfected with small interfering RNA (siRNA-TPT1-AS1), the invasion and migration of HepG2 cells were detected by transwell assay and wound healing assay. Western blot was used to measure the epithelial-mesenchymal transition (EMT) process and the activity of the PI3K/AKT pathway.

RESULTS

TPT1-AS1 was up-regulated in hepatopcarcinoma tissues and cell lines Huh7, SMMC-7721, HCCLM3, and HepG2. Transfection with siRNA-TPT1-AS1 noticeably restrained HepG2 cell invasion and migration, and suppressed the EMT process. Furthermore, TPT1-AS1 knockdown reduced MMP-9 expression and inhibited the activation of the PI3K/AKT pathway.

CONCLUSION

TPT1-AS1 is up-n regulated in hepatic carcinoma. Knockdown of TPT1-AS1 inhibits the invasion and migration of HepG2 cells via mechanisms that may be associated with reducing the activity of PI3K/AKT pathway and the expression of its downstream gene MMP-9, and inhibiting the EMT process.

Development and analysis of long non-coding RNA-associated competing endogenous RNA network for osteosarcoma metastasis

Background

Osteosarcoma is the primary bone malignant neoplasm that often develops metastasis. Increasing evidences have shown that non-coding RNAs (ncRNAs) relate to the progression of osteosarcoma. However, the ncRNAs’ roles in osteosarcoma metastasis are still unknown.

Methods

Differentially expressed (DE) RNAs were identified from Gene Expression Omnibus (GEO) database. Protein-protein interaction (PPI) of DE messenger RNAs (DEmRNAs) was built through STRING database. The target mRNAs and long ncRNAs (lncRNAs) of microRNAs (miRNA) were predicted through miRDB, Targetscan and Genecode databases, which then cross-checked with previously obtained DERNAs to construct competing endogenous RNA (ceRNA) network. All networks were visualized via Cytoscape and the hub RNAs were screened out through Cytoscape plug-in Cytohubba. The gene functional and pathway analyses were performed through DAVID and MirPath databases. The survival analyses of hub RNAs were obtained through Kaplan-Meier (KM) survival curves.

Results

Five hundred sixty-four DEmRNAs, 16 DElncRNAs and 22 DEmiRNAs were screened out. GO functional and KEGG pathway analyses showed that DERNAs were significantly associated with tumor metastasis. The ceRNA network including 6 lncRNAs, 55 mRNAs and 20 miRNAs were constructed and the top 10 hub RNAs were obtained. Above all, PI3K/AKT signaling pathway was identified as the most important osteosarcoma metastasis-associated pathway and its hub ceRNA module was constructed. The survival analyses showed that the RNAs in hub ceRNA module closely related to osteosarcoma patients’ prognosis.

Conclusions

The current study provided a new perspective on osteosarcoma metastasis. More importantly, the RNAs in hub ceRNA module might act as the novel therapeutic targets and prognostic factors for osteosarcoma patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41065-021-00174-0.

Knockdown of TPT1-AS1 inhibits cell proliferation, cell cycle G1/S transition, and epithelial-mesenchymal transition in gastric cancer

Long non-coding RNAs are considered to be critical regulators of tumor progression. Tumor protein translationally controlled 1 antisense RNA 1 (TPT1-AS1) was shown to have an oncogenic role in cervical and ovarian cancer. The clinical significance and biological function of TPT1-AS1 in gastric cancer (GC) are not clear. In this study, we analyzed the expression of TPT1-AS1 in GC tissues and cell lines and performed functional and mechanistic analysis of TPT1-AS1 effects on GC cell proliferation, migration, and invasion. TPT1-AS1 expression was determined in 76 pairs of GC tissues vs. matched adjacent normal tissues and in four GC cell lines (SGC-7901, AGS, BGC-823, and MGC-803) vs. GES-1 cell line by quantitative reverse transcription PCR. SGC-7901 and MGC-803 cells were transfected with small interfering RNA or scrambled negative control, and cell proliferation, colony formation, migration, invasion and cell cycle assays were performed. The expression of proteins involved in cell cycle progression and epithelial-mesenchymal transition was analyzed by Western blot. TPT1-AS1 expression was significantly higher in GC tissues and cell lines compared to controls. The overexpression of TPT1-AS1 was significantly correlated with TNM stage and lymph node metastasis, and it was associated with worse prognosis of GC patients according to the Kaplan-Meier survival analysis and Cox proportional hazard regression analysis. The knockdown of TPT1-AS1 significantly inhibited proliferation, cell cycle G1/S transition, migration, and invasion of SGC-7901 and MGC-803 cells. Moreover, TPT1-AS1 knockdown downregulated the expression of cyclin-dependent kinase (CDK) 4, cyclin D1, and vimentin and upregulated the expression of p21 and E-cadherin. Our findings suggest that TPT1-AS1 may be a promising therapeutic target in GC.

EZH2-mediated lncRNA ABHD11-AS1 promoter regulates the progression of ovarian cancer by targeting miR-133a-3p

Long-chain noncoding RNAs (lncRNAs) are involved in a wide range of biological and pathological processes in ovarian cancer. The purpose of this study was to investigate the effects of EZH2-mediated ABHD11-AS1 promoter on the pathogenesis of ovarian cancer. The expression levels of EZH2, ABHD11-AS1 and miR-133a-3p were examined in ovarian cancer tissues using reverse transcription-quantitative PCR. Cell proliferation was evaluated using cell counting kit 8 assay, and cell invasion/migration was determined using a Transwell assay. Cell apoptosis was evaluated using flow cytometry. Dual luciferase assay was performed to confirm the interaction between ABHD11-AS1 and miR-133a-3p. The binding site of H3K27me3 on ABHD11-AS1 promoter was confirmed by ChIP. The expression of ABHD11-AS1 was significantly upregulated in ovarian cancer samples, and its levels were closely associated with lymph node metastasis, tumor stage and 3-year survival rate. Furthermore, interference of ABHD11-AS1 suppressed the proliferation, migration and invasion of ovarian cancer cells, while cell apoptosis was promoted. Additionally, miR-133a-3p could be a novel target of ABHD11-AS1, and EZH2-mediated H3K27me3 protein might bind to ABHD11-AS1 promoter directly. Moreover, rescue experiments indicated that the effects caused by ABHD11-AS1 knockdown on the malignant characteristics of ovarian cancer cells were notably enhanced by miR-133a-3p mimics, whereas the influences on cell growth and metastasis induced by overexpressed ABHD11-AS1 were abrogated by the restoration of miR-133a-3p expression. In summary, EZH2-mediated enrichment of H3K27me3 on ABHD11-AS1 promoter could regulate the progression of ovarian cancer via miR-133a-3p. Therefore, EZH2/ABHD11-AS1/miR-133a-3p axis might be a putative candidate for targeted treatment of ovarian cancer.

Long noncoding RNA TPT1-AS1 promotes the progression and metastasis of colorectal cancer by upregulating the TPT1-mediated FAK and JAK-STAT3 signalling pathways

Tumour protein translationally controlled 1 (TPT1) antisense RNA 1 (TPT1-AS1) is known to be involved in the development and metastasis of cervical and ovarian cancers; however, its biological role in colorectal cancer (CRC) remains unknown. This study aimed to determine the function and mechanism of action of TPT1-AS1 in the progression and metastasis of CRC. Elevated TPT1-AS1 levels were observed in CRC tissues. Furthermore, the high expression levels were found to be correlated with unfavourable clinicopathological characteristics in CRC. Cell function experiments demonstrated that TPT1-AS1 depletion impeded cell proliferation, migration and invasion and enhanced cell adhesion; it also attenuated tumorigenesis and metastasis in vivo. Additionally, TPT1-AS1 was predominately located in the nuclei of the cells and could upregulate the expression of TPT1 by recruiting mixed lineage leukaemia protein-1 (MLL1), which increased the trimethylation of H3K4 me3 in the TPT1 promoter region and subsequently activated FAK and JAK-STAT3 signalling cascades. The inhibition of FAK activation by PF573228 significantly attenuated the oncogenic effect of TPT1-AS1. These findings indicated that TPT1-AS1 promoted tumour progression and metastasis in CRC by upregulating TPT1 levels and activating the FAK and JAK-STAT3 signalling pathways. Thus, TPT1-AS1 may be considered as a potential therapeutic target for CRC.

Gynecologic cancers and non-coding RNAs: Epigenetic regulators with emerging roles

Gynecologic cancers involve the female genital organs, such as the vulva, vagina, cervix, endometrium, ovaries, and fallopian tubes. The occurrence and frequency of gynecologic cancer depends on personal lifestyle, history of exposure to viruses or carcinogens, genetics, body shape, and geographical habitat. For a long time, research into the molecular biology of cancer was broadly restricted to protein-coding genes. Recently it has been realized that non-coding RNAs (ncRNA), including long noncoding RNAs (LncRNAs), microRNAs, circular RNAs and piRNAs (PIWI-interacting RNAs), can all play a role in the regulation of cellular function within gynecological cancer. It is now known that ncRNAs are able to play dual roles, i.e. can exert both oncogenic or tumor suppressive functions in gynecological cancer. Moreover, several clinical trials are underway looking at the biomarker and therapeutic roles of ncRNAs. These efforts may provide a new horizon for the diagnosis and treatment of gynecological cancer. Herein, we summarize some of the ncRNAs that have been shown to be important in gynecological cancers.

Dyregulation of the lncRNA TPT1-AS1 positively regulates QKI expression and predicts a poor prognosis for patients with breast cancer

The long noncoding RNA (lncRNA) TPT1-AS1 has been reported to be involved in the development of multiple cancers. However, its clinical value, biological function, and underlying molecular mechanism in breast cancer (BC) remain unclear. In the present study, TPT1-AS1 expression was decreased in BC tissues, based on RNA-seq data download from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases and the qRT-PCR results confirmed the above findings. Otherwise, low TPT1-AS1 expression was significantly associated with some clinical features of malignancy, such as high TNM stage, lymph node metastasis, a Her-2-negative status, and shorter overall survival. More importantly, univariate and multivariate Cox regression analyses indicated that TPT1-AS1 is an independent prognostic factor for patients with BC. Overexpression and knockdown of TPT1-AS1 in BC cell lines altered their proliferation, metastasis and invasion, as measured using the cell counting kit-8 (CCK-8) assay, wound-healing assay and transwell assay, respectively. In addition, a dual luciferase activity reporter assay validated that TPT1-AS1 and QKI shared a binding site in miR-330-3p. Based on these findings, TPT1-AS1 potentially represents a prognostic biomarker for patients with BC and participates in the development of BC through the TPT1-AS1/miR-330-3p/QKI axis.

Long non‑coding RNA PCAT6 promotes the development of osteosarcoma by increasing MDM2 expression

Osteosarcoma is a severe malignant tumor. Several studies indicated that lncRNA prostate cancer-associated transcript 6 (PCAT6) promoted the development of multiple types of cancers. Studies have also revealed that MDM2 could aggravate tumor symptoms inhibiting P53 expression. However, whether lncRNA PCAT6 could affect the proliferation and metastasis of osteosarcoma cells by regulating P53 expression is unclear. The present study established lncRNA PCAT6-overexpressing osteosarcoma cells. Cell Counting Kit-8, wound healing and Transwell assays were performed to detect the change in proliferation, migration and invasion of these cells, respectively. Subsequently, E3 ubiquitin-protein ligase Mdm2 (MDM2), P53 and P21 expression were determined using western blotting. Finally, MDM2 expression was inhibited and the proliferation, migration and invasion of these cells was determined again. The present study found that the proliferation, migration and invasion of osteosarcoma cells increased following overexpression of lncRNA PCAT6. MDM2 expression was upregulated while the levels of P53 and P21 decreased following overexpression of lncRNA PCAT6. However, the proliferation, migration and invasion of osteosarcoma cells were inhibited following MDM2 knockdown. Additionally, P53 and P21 was rescued following MDM2 knockdown. To conclude, lncRNA PCAT6 promoted the proliferation, migration and invasion of osteosarcoma cells by promoting the expression of MDM2 and suppressing the expression of P53 and P21.

LncRNA GAS8-AS1 Inhibits Ovarian Cancer Progression Through Activating Beclin1-Mediated Autophagy

Background

Early detection and diagnosis of ovarian cancer (OC) is complicated due to the concealment of the ovarian anatomical position and the lack of clinical manifestations and specific indicators of early OC. Therefore, it is urgent to study the pathogenesis of OC, especially the molecular mechanism.

Results

LncRNA GAS8-AS1 was decreased in OC tissues and cell lines, and high expression of GAS8-AS1 indicated a higher 5-year survival rate of OC patients. Overexpression of GAS8-AS1 suppressed growth of OC cells, while deletion of GAS8-AS1 promoted the progression of OC cells. Further data indicated GAS8-AS1 activated autophagy in OC cells. Functional experiments showed that 3-MA removed the inhibitory effect of GAS8-AS1 in OC cells. On the contrary, Rapamycin reversed the promoting effect of GAS8-AS1 in OC cells. Furthermore, GAS8-AS1 bound with Beclin1 and promoted its expression, and silencing of Beclin1 reversed the inhibitory role of GAS8-AS1 in OC progression. In vivo tumorigenesis assay showed GAS8-AS1 suppressed OC progression and activated Beclin1 mediated autophagy.

Conclusion

Our study suggested GAS8-AS1 inhibited OC progression by activating autophagy via binding with Beclin1, and GAS8-AS1 might be a potential therapeutic target for OC clinical treatment.

LncRNA TPT1-AS1 Sponges miR-23a-5p in Glioblastoma to Promote Cancer Cell Proliferation

Background: Long noncoding RNA (LncRNA) TPT1-AS1 is an oncogene in ovarian cancer and cervical cancer, while its role in glioblastoma (GBM) is unknown. The bioinformatics analysis in this study showed that miR-23a-5p may bind to TPT1-AS1. This study was performed to investigate the interactions between miR-23a-5p and TPT1-AS1 in GBM. Materials and Methods: A total of 60 GBM patients (40 males and 20 females, 24 to 60 years old, mean age 41.7 ± 7.8 years old) were enrolled at the First Hospital of Jilin University between April 2016 and April 2018. Gene expression levels were determined by qPCR and Western blot. Cell transfections were performed to analyze the interactions between TPT1-AS1, miR-23a-5p, and extracellular matrix protein 1 (ECM1). Cell proliferation was detected by cell proliferation assay. Results: The authors found miR-23a-5p was downregulated in GBM and TPT1-AS1 was upregulated in GBM, whereas the expression of these two was not significantly correlated. In GBM cells, overexpression of TPT1-AS1 did not affect the expression of miR-23a-5p, but upregulated ECM1. In cell proliferation assay, overexpression of TPT1-AS1 and ECM1 resulted in increased proliferation rate of GBM cells. Overexpression of miR-23a-5p attenuated the effects of overexpressing TPT1-AS1. Conclusions: TPT1-AS1 may sponge miR-23a-5p in GBM to promote cancer cell proliferation by upregulating ECM1.

MiR-216a-5p inhibits tumorigenesis in Pancreatic Cancer by targeting TPT1/mTORC1 and is mediated by LINC01133

MiR-216a-5p has opposite effects on tumorigenesis and progression in the context of different tumors, acting as either a tumor suppressor or an oncogene. However, the expression and function of miR-216a-5p in pancreatic cancer (PC) is not well characterized. In this study, we found miR-216a-5p was significantly downregulated in PC tissues and cell lines, which showed a negative correlation with peripancreatic lymph, perineural invasion and TNM stage of PCs patients. We made use of functional assays to reveal that miR-216a-5p inhibited growth and migration of PC cells in vitro and in vivo. Then, by employing the bioinformatics analysis and luciferase reporter assay, we demonstrated TPT1 was a potential target of miR-216a-5p, which contributes to tumor malignance by mediating mTORC1 pathway-associated autophagy. Furthermore, bioinformatics analysis and RNA pulldown confirmed that miR-216a-5p was mediated by LINC01133, which sponge miR-216a-5p, as a competing endogenous RNA (ceRNA). Collectively, our study revealed an important role of LINC01133/miR-216a-5p/TPT1 axis in the genesis and progression of PCs, which provides potential biomarkers for clinical diagnosis and therapy of PCs.

TMPO-AS1 promotes cell proliferation of thyroid cancer via sponging miR-498 to modulate TMPO

Background

Thyroid cancer (TC) is the most frequent endocrine malignancy. Long noncoding RNAs (lncRNAs) have been confirmed to act as significant roles in tumor development. The role of lncRNA TMPO-AS1 in TC is still unclear, so it remains to be explored. The aim of the research is to investigate the role and regulatory mechanism of TMPO-AS1 in TC.

Methods

TMPO-AS1 and TMPO expression in TC tumors and cells was detected by TCGA database and QRT-PCR assay respectively. CCK-8, EDU, TUNEL and western blot assays were conducted to identify the biological functions of TMPO-AS1 in TC. Luciferase reporter and RNA pull down assays were conducted to measure the interaction among TMPO-AS1, TMPO and miR-498.

Results

TMPO-AS1 was overexpressed in TC tissues and cell lines. Knockdown of TMPO-AS1 suppressed cell growth and accelerated cell apoptosis in TC. Furthermore, downregulation of TMPO-AS1 suppressed TMPO expression in TC. The data suggested that TMPO expression was upregulated in TC tissues and cell lines and was positively correlated with TMPO-AS1 expression in TC. Furthermore, the expression of miR-498 presented low expression in TC cells. And miR-498 expression was negatively regulated by TMPO-AS1, meanwhile, TMPO expression was negatively regulated by miR-498 in TC cells. Besides, it was confirmed that TMPO-AS1 could bind with miR-498 and TMPO in TC cells. In addition, it was validated that TMPO-AS1 elevated the levels of TMPO via sponging miR-498 in TC cells.

Conclusions

TMPO-AS1 promotes cell proliferation in TC via sponging miR-498 to modulate TMPO.

miR-744-5p inhibits cellular proliferation and invasion via targeting ARF1 in epithelial ovarian cancer

miR-744-5p has been demonstrated to play an important role in cancer progression. However, the functions of miR-744-5p in epithelial ovarian cancer (EOC) are not well clarified. In this study, our aim was to investigate the role of miR-744-5p and its underlying molecular mechanism in cell progression of EOC. EOC clinical tissues and matched adjacent ovarian epithelial tissues were collected from 18 patients. Tissues and cell lines were analyzed by qPCR or Western blot to investigate the expression of miR-744-5p and ARF1 in EOC. Cell proliferative capacity was assessed by CCK8 and colony formation assays. Wound healing and transwell assays were performed to evaluate cell migration and invasion. The potential binding relation between miR-744-5p and IRF1 was demonstrated by dual luciferase report assay. The results showed that expression of miR-744-5p was low in EOC clinical tissues and cells. Overexpression of miR-744-5p inhibited proliferation, migration, and invasion of EOC cells. Further mechanistic study identified that ARF1 is a target of miR-744-5p, which is negatively correlated with the expression of miR-744-5p, and overexpression of ARF1 could reverse the inhibition of miR-744-5p on the proliferation, migration, and invasion of EOC cells. Taken together, our results indicated that miR-744-5p attenuated EOC progression via targeting IRF1, providing potential guidance for the clinical treatment of ovarian cancer.

DARS-AS1 promotes clear cell renal cell carcinoma by sequestering miR-194-5p to up-regulate DARS

Clear cell renal cell carcinoma (ccRCC), the most frequent subtype of renal cell carcinoma (RCC), is characterized by high relapse rate and mortality. Long non-coding RNAs (lncRNAs) are critical participants during cancer development. LncRNA DARS antisense RNA 1 (DARS-AS1), a newly-found lncRNA, is not specifically reported in ccRCC. However, Gene Expression Profiling Interactive Analysis (GEPIA) and starBase databases revealed the up-regulation of DARS-AS1 in ccRCC. Current study investigated the function and mechanism of DARS-AS1 in ccRCC. Functional assays including colony formation assay, EdU assay, caspase-3 activity detection, flow cytometry analysis and JC-1 assay were implemented to identify the role of DARS-AS1 in ccRCC. As a result, silencing of DARS-AS1 retarded proliferation and facilitated apoptosis in ccRCC cells. Moreover, mainly a cytoplasmic localization of lncRNA DARS-AS1 was verified in ccRCC cells. Then, we demonstrated that DARS-AS1 positively regulated its nearby gene, aspartyl-tRNA synthetase (DARS), by sequestering miR-194-5p. Moreover, DARS was testified as the oncogene in ccRCC and DARS-AS1 worked as a tumor-facilitator in ccRCC through miR-194-5p/DARS signaling. In a summary, this study firstly uncovered that DARS-AS1 boosted DARS expression via absorbing miR-194-5p, therefore contributing to malignancy in ccRCC. Our findings may be helpful for opening new strategies for ccRCC treatment.

lncRNA PVT1 Promotes Tumorigenesis of Colorectal Cancer by Stabilizing miR-16-5p and Interacting with the VEGFA/VEGFR1/AKT Axis

Recently, the long noncoding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) was reported to be involved in the pathogenesis of several cancers, including human colorectal cancer (CRC). However, the molecular basis for cancer initiation, development, and progression remains unclear. In this study, we observe that upregulated PVT1 is associated with poor prognosis and bad clinicopathological features of CRC patients. In vitro means of PVT1 loss in a CRC cell line inhibit cell proliferation, migration, and invasion. Furthermore, dual-luciferase reporter and RNA pull-down assays indicated that PVT1 binds to miR-16-5p, which has been shown to play strong tumor suppressive roles in CRC. Targeted loss of miR-16-5p partially rescues the suppressive effect induced by PVT1 knockdown. Vascular endothelial growth factor A (VEGFA), a direct downstream target of miR-16-5p, was suppressed by PVT1 knockdown in CRC cells. Overexpression of VEGFA is known to modulate the AKT signaling cascade by activating vascular endothelial growth factor receptor 1 (VEGFR1). We, therefore, show that PVT1 loss combined with miR-16-5p overexpression reduces tumor volume maximally when propagated within a mouse xenograft model. We conclude that the PVT1-miR-16-5p/VEGFA/VEGFR1/AKT axis directly coordinates the response in CRC pathogenesis and suggest PVT1 as a novel target for potential CRC therapy.

The Challenges and Opportunities of LncRNAs in Ovarian Cancer Research and Clinical Use

Ovarian cancer is one of the most lethal gynecological malignancies worldwide because it tends to be detected late, when the disease has already spread, and prognosis is poor. In this review we aim to highlight the importance of long non-coding RNAs (lncRNAs) in diagnosis, prognosis and treatment choice, to make progress towards increasingly personalized medicine in this malignancy. We review the effects of lncRNAs associated with ovarian cancer in the context of cancer hallmarks. We also discuss the molecular mechanisms by which lncRNAs become involved in cellular physiology; the onset, development and progression of ovarian cancer; and lncRNAs' regulatory mechanisms at the transcriptional, post-transcriptional and post-translational stages of gene expression. Finally, we compile a series of online resources useful for the study of lncRNAs, especially in the context of ovarian cancer. Future work required in the field is also discussed along with some concluding remarks.

Long non-coding RNA TPT1-AS1 promotes angiogenesis and metastasis of colorectal cancer through TPT1-AS1/NF90/VEGFA signaling pathway

LncRNAs have been proven closely correlated to tumor progression. A recent study identified LncRNA TPT1-AS1 (TPT1-AS1) as one of the liver-metastasis associated LncRNAs in colorectal cancer (CRC). In this study, we report that TPT1-AS1 is upregulated in CRC tissues, which is associated with poor prognosis. Functional assays unravel a pro-angiogenesis and metastasis role of TPT1-AS1. Mechanistically, Flexmap 3D assays reveal that TPT1-AS1 upregulates the VEGFA secretion in CRC cells. RNA immunoprecipitation and mRNA stability assays further show that TPT1-AS1 interacts with nuclear factor 90 (NF90) and subsequently promotes the association between NF90 and VEGFA mRNA, which leads to the upregulation of VEGFA mRNA stability. Therefore, we elucidate a new regulatory mechanism of TPT1-AS1 in CRC angiogenesis and targeting the TPT1-AS1/NF90/VEGFA axis may provide a useful strategy for diagnosis and treatment for colorectal cancer patients.

Identification of prognostic long noncoding RNAs associated with spontaneous regression of neuroblastoma

Background

The association between long noncoding RNAs (lncRNAs) and spontaneous regression of neuroblastoma (NB) has rarely been investigated and remains unknown.

Objective

To identify prognostic lncRNAs involved in the spontaneous regression of NB.

Methods

Differential expression analyses were performed between those samples with an outcome of death in stage 4 NB group and those samples with an outcome of survival in stage 4S NB group in two independent public datasets, respectively. Univariate Cox proportional hazard regression survival analysis was performed in each of the entire cohort to identify those lncRNAs significantly associated with overall survival (OS). Those lncRNAs independently associated with OS were then identified by multivariate Cox survival analysis and used to construct an lncRNA risk score.

Results

A total of 20 differentially expressed and survival‐related lncRNAs were identified sharing between the two independent cohorts. The expression of each of these 20 lncRNAs was significantly correlated with the expression of NTRK1, which is a well‐known factor involved in NB spontaneous regression. Four lncRNAs (LNC00839, FIRRE, LOC283177, and LOC101928100) were identified to be significantly associated with survival independent with each other and a four‐lncRNA signature risk score was constructed. Patients with high lncRNA signature risk score had a significantly poorer OS and event‐free survival than those with low lncRNA signature risk score. The four‐lncRNA signature has a good performance in predicting survival independent with MYCN amplification (nonamplified vs amplified), age status (<18 months vs ≥18 months), risk status (low risk vs high risk), and International Neuroblastoma Staging System (INSS) stage (INSS 1/2/3/4S vs INSS 4).

Conclusions

We identified 20 survival‐related lncRNAs that might be associated with the spontaneous regression of NB and developed a four‐lncRNA signature risk score. The four‐lncRNA signature is an independent prognostic factor for survival of NB patients.

Construction and Investigation of an LINC00284-Associated Regulatory Network in Serous Ovarian Carcinoma

The low survival rate associated with serous ovarian carcinoma (SOC) is largely due to the lack of relevant molecular markers for early detection and therapy. Increasing experimental evidence has demonstrated that long noncoding RNAs (lncRNAs) are involved in cancer initiation and development, and a competitive endogenous RNA (ceRNA) hypothesis has been formulated. Therefore, the characterization of new lncRNA and lncRNA-related networks is crucial for early diagnosis and targeted therapy of SOC. Data on lncRNAs, mRNAs, and miRNAs with differential expression in SOC, compared to normal ovarian tissue, were obtained from the Gene Expression Omnibus (GEO) database. Data on lncRNA expression and clinical data in SOC were obtained from The Cancer Genome Atlas (TCGA). lncRNA-miRNA interactions were predicted by the miRBase database. Different online tools, i.e., TargetScan, RNA22, miRmap, microT, miRanda, StarBase, and PicTar, were cooperatively utilized to predict the mRNAs targeted by miRNAs. The plugin of BiNGO in Cytoscape and KOBAS 3.0 were used to conduct the functional and pathway enrichment analyses. The lncRNA, miRNAs, and mRNAs identified to be expressed at statistically significant and different levels between SOC and healthy fallopian tube tissues were further validated using qRT-PCR. A total of 4 lncRNAs (LINC00284, HAGLR, HCAT158, and BLACAT1) and 111 mRNAs were found to be upregulated in SOC tissues compared to normal tissues, based on the GEO database. LINC00284 was found to be highly expressed in SOC, in association with the upregulation of the transcription factor SOX9. The high LINC00284 expression was associated with poor prognosis and proved to be an independent risk factor in patients with SOC, based on TCGA database. The qRT-PCR validation results closely recapitulated the expression profiles and prognostic scores of the aforementioned bioinformatic analyses. The LINC00284-related ceRNA network was found to be associated with SOC carcinogenesis by biofunctional analysis. In conclusion, the LINC00284-related ceRNA network may provide valuable information on the mechanisms of SOC initiation and progression. Importantly, LINC00284 proved to be a new potential prognostic biomarker for SOC.