Long non-coding RNAs in metastasis

Emerging roles of long noncoding RNAs in enzymes related intracellular metabolic pathways in cancer biology

Metabolic reprogramming plays critical roles in the development and progression of tumor by providing cancer cells with a sufficient supply of nutrients and other factors needed for fast-proliferating. Emerging evidence indicates that long noncoding RNAs (lncRNAs) are involved in the initiation of metastasis via regulating the metabolic reprogramming in various cancers. In this paper, we aim to summarize that lncRNAs could participate in intracellular nutrient metabolism including glucose, amino acid, lipid, and nucleotide, regardless of whether lncRNAs have tumor-promoting or tumor-suppressor function. Meanwhile, modulation of lncRNAs in glucose metabolic enzymes in glycolysis, pentose phosphate pathway and tricarboxylic acid cycle (TCA) in cancer is reviewed. We also discuss therapeutic strategies targeted at interfering with enzyme activity to decrease the utilization of glucoses, amino acid, nucleotide acid and lipid in tumor cells. This review focuses on our current understanding of lncRNAs participating in cancer cell metabolic reprogramming, paving the way for further investigation into the combination of such approaches with existing anti-cancer therapies.

Long non-coding RNA TINCR suppresses growth and epithelial-mesenchymal transition by inhibiting Wnt/β-catenin signaling pathway in human pancreatic cancer PANC-1 cells: Insights from in vitro and in vivo studies

There is increasing evidence that long non-coding RNAs (lncRNAs) play a crucial role in the development and progression of malignant tumors, particularly pancreatic cancer. In this study, the influence of the lncRNA TINCR on the behavior of human pancreatic cancer cells was investigated with the aim of deciphering its role in growth, migration, and invasion. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to investigate TINCR expression in pancreatic cancer cells. Ectopic expression of TINCR in PANC-1 cells was induced to evaluate the effects on cell viability and apoptosis, examining the apoptotic genes Bax and Bcl-2. Migration and invasion assays were used to measure the impact of TINCR on these cellular processes. In vivo studies using a xenograft mouse model examined the effects of TINCR on tumor growth, epithelial-to-mesenchymal transition (EMT) markers, and the Wnt/β-catenin signaling pathway. PANC-1 cells showed strikingly low TINCR expression compared to other pancreatic cancer cell lines. Ectopic TINCR expression reduced the viability of PANC-1 cells primarily by inducing apoptosis, as evidenced by increased Bax and decreased Bcl-2 expression. Overexpression of TINCR significantly increased the percentage of apoptotic cells. It also decreased the migration and invasion ability of PANC-1 cells, as demonstrated in wound healing and transwell assays. In addition, overexpression of TINCR-suppressed proteins is associated with the Wnt/β-catenin signaling pathway in PANC-1 cells. In the xenograft mouse model, overexpression of TINCR inhibited tumor growth, EMT markers, and proteins associated with the Wnt/β-catenin pathway. This study sheds light on the tumour-suppressive role of TINCR in PANC-1 cells and suggests its potential as a therapeutic target. These results shed light on the molecular mechanisms underlying the impact of TINCR on pancreatic cancer and offer promising opportunities for innovative therapeutic strategies to improve outcomes in this serious malignancy.

Comprehensive analysis of cuproptosis-related lncRNAs signature to predict prognosis in bladder urothelial carcinoma

BACKGROUND

Cuproptosis-related genes (CRGs) have been recently discovered to regulate the occurrence and development of various tumors by controlling cuproptosis, a novel type of copper ion-dependent cell death. Although cuproptosis is mediated by lipoylated tricarboxylic acid cycle proteins, the relationship between cuproptosis-related long noncoding RNAs (crlncRNAs) in bladder urothelial carcinoma (BLCA) and clinical outcomes, tumor microenvironment (TME) modification, and immunotherapy remains unknown. In this paper, we tried to discover the importance of lncRNAs for BLCA.

METHODS

The BLCA-related lncRNAs and clinical data were first obtained from The Cancer Genome Atlas (TCGA). CRGs were obtained through Coexpression, Cox regression and Lasso regression. Besides, a prognosis model was established for verification. Meanwhile, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, gene ontology (GO) analysis, principal component analysis (PCA), half-maximal inhibitory concentration prediction (IC50), immune status and drug susceptibility analysis were carried out.

RESULTS

We identified 277 crlncRNAs and 16 survival-related lncRNAs. According to the 8-crlncRNA risk model, patients could be divided into high-risk group and low-risk group. Progression-Free-Survival (PFS), independent prognostic analysis, concordance index (C-index), receiver operating characteristic (ROC) curve and nomogram all confirmed the excellent predictive capability of the 8-lncRNA risk model for BLCA. During gene mutation burden survival analysis, noticeable differences were observed in high- and low-risk patients. We also found that the two groups of patients might respond differently to immune targets and anti-tumor drugs.

CONCLUSION

The nomogram with 8-lncRNA may help guide treatment of BLCA. More clinical studies are necessary to verify the nomogram.

Identification and validation of long noncoding RNA AC083900.1 and RP11-283C24.1 for prediction of progression of osteosarcoma

BACKGROUND

The role of cuproptosis, an emerging cell death pathway that makes a remarkable contribution to tumor progression, remains elusive in osteosarcoma (OS), in addition to its regulator, including long-no-coding RNAs (lncRNAs) that are also a critical factor for fueling OS.

METHODS

Transcriptome and clinical data from 70 normal human bone tissue samples and 84 frozen clinical osteosarcoma samples were included in this study. Cuproptosis-associated lncRNAs (CRlncs) were identified through differential expression and co-expression analyses. Univariate Cox regression was performed to screen for prognostic lncRNAs, then we used least absolute shrinkage and selection operator regression to distinguish prognosis-related CRlncs (AC083900.1 and RP11-283C24.1) for modeling the CRlncs prognostic signature (CLPS) by multivariate Cox regression using the stepwise method. CLPS performance was tested by independent prognostic analyses, survival curve and receiver operating characteristic (ROC) curve. In addition, the molecular and immune mechanisms that underlie the unfavorable prognosis of CLPS-identified high-risk group were elucidated.

RESULT

AC083900.1 and RP11-283C24.1 have been identified as the most important CRlncs for OS progression (hazard ratio: 3.498 and 2.724, respectively), and the derived CLPS demonstrated outstanding performance for the prediction of OS prognosis (AUC of 0.799 and 0.778 in the training and test sets, both adj-p < 0.05 in survival curve). As was anticipated, CLPS also outperformed a recent clinical prognostic approach that only achieved an AUC of 0.682 [metastasis]. It is notable that AC083900.1 progressed OS metastasis, evidenced by its high expression in metastatic OS, its high correlation to metastasis-related genes, and its high AUC of 0.683 for the prediction of metastasis. Mechanistically, AC083900.1 and RP11-283C24.1 dysregulated many critical biological processes regarding humoral immune response, immunoglobulin complex, etc.; while reducing the infiltration of many cytotoxic immune cells (B-cells, TIL, neutrophils, etc.). It is encouraging that BMS-509744 and KIN001-135 demonstrated high therapeutic implications for CLPS-identified high-risk OS, and the low-risk counterpart was sensitive to SB-216763. Quantitative RT-PCR analysis showed that both AC083900.1 and RP11-283C24.1 were significantly upregulated in different osteosarcoma cell lines.

CONCLUSION

This study elucidated the roles and mechanisms of AC083900.1 and RP11-283C24.1 in the development of OS, fostering a reliable prognostic approach and treatment for OS patients.

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.

The role of lncRNA CERS6-AS1 in cancer and its molecular mechanisms: A systematic review and meta-analysis

BACKGROUND

LncRNAs have the potential to play a regulatory role in different processes of cancer development and progression. We conducted a systematic review and meta-analysis of evidence on the clinical significance and prognostic value of lncRNA CERS6-AS1 in cancer.

METHODS

This systematic review was conducted following PRISMA guidelines. Medline and Embase databases were searched using the relevant key terms covering lncRNA CERS6-AS1 and cancer. We pooled the estimated effect sizes and their 95 % confidence interval (CI) using random-effects models in STATA 16.0 (StataCorp, College Station, TX, USA).

RESULTS

Eleven articles on pancreatic, colorectal, gastric, papillary thyroid, breast, and hepatocellular cancers fulfilled our eligibility criteria. Studies consistently found that lncRNA CERS6-AS1 expression is upregulated in all assessed cancers. Based on our meta-analysis, its aberrant expression was directly associated with unfavorable clinical outcomes, including higher stage (pooled Odds ratios (95 % CI): 3.15 (2.01-4.93; I² = 0.0 %), tumor size (1.97 (1.27-3.05; I² = 37.8 %), lymph node metastasis (6.48 (4.01-10.45; I² = 0.40 %), and poor survival (Pooled log-rank test P-value < 0.001) in patients. Regarding potential mechanisms, functional studies revealed that LncRNA CERS6-AS1 is involved in cancer growth mainly by sponging miRNAs and regulating their downstream targets.

CONCLUSION

Available evidence suggests that LncRNA CERS6-AS1 is upregulated in different cancers and has an oncogenic role. LncRNA CERS6-AS1 expression level might predict cancer prognosis, highlighting its potential application as a prognostic biomarker for cancer.

Comprehensive analysis of cuproptosis-related long noncoding RNA immune infiltration and prediction of prognosis in patients with bladder cancer

Background: Bladder cancer (BCa), among the world’s most common malignant tumors in the urinary system, has a high morbidity and mortality. Though cuproptosis is a new type of cell death mediated by lipoylated tricarboxylic acid (TCA) cycle proteins, the role of cuproptosis-related long noncoding RNAs (crlncRNAs) in bladder tumors awaits further elucidation. In this paper, we tried to explore how important crlncRNAs are for BCa.

Methods: The crlncRNAs were first obtained through Pearson correlation analysis of the RNA-seq data and corresponding clinical data downloaded from The Cancer Genome Atlas (TCGA). Then, three lncRNAs were acquired by Cox regression and Lasso regression to build a prognostic model of crlncRNAs for verification. In the meantime, clinicopathological correlation analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, principal component analysis (PCA), immunoassay, and half-maximal inhibitory concentration prediction (IC50) were carried out. Then, an entire tumor was classified into two clusters by crlncRNA expression to further discuss the differences in prognosis, immune status and drug susceptibility among different subgroups.

Results: We obtained a total of 152 crlncRNAs and built a risk model for screened crlncRNAs. We validated the model and found that calibration charts feature a high consistency in verifying nomogram prediction. Receiver operating characteristic (ROC) curve and univariate and multivariate Cox regression suggested that this model can be applied as an independent prognostic factor of bladder cancer due to its high accuracy. According to KEGG analysis, high-risk groups were enriched in cancer and immune-related pathways. During tumor immunoassay, noticeable differences were observed in both immune infiltration and checkpoints between high- and low-risk patients. Of the two subgroups divided among patients by consensus clustering, cluster 2 had a better prognosis, whereas cluster 1 had higher immunoreactivity scores, more immune cell infiltrations and immune checkpoint expressions, and different sensitivities to drugs.

Conclusion: The research findings demonstrate that crlncRNAs can be used to predict the prognosis and immune microenvironment of patients suffering from BCa, and differentiate between BCa subgroups to improve the individual therapy of BCa.

Construction and validation of a cuproptosis-related lncRNA signature as a novel and robust prognostic model for colon adenocarcinoma

Background

Cuproptosis, a newly identified form of programmed cell death, is thought to play a role in tumorigenesis. Long non-coding RNAs (lncRNAs) are reported to be associated with tumor progression and prognosis in colon adenocarcinoma (COAD). However, the role and prognostic value of cuproptosis-related lncRNAs in COAD remains unknown. This study is devoted to constructing and validating a cuproptosis-related lncRNA signature that can predict COAD patient outcomes using bioinformatics methods.

Methods

The COAD mRNA and lncRNA expression profiles and corresponding clinical data were downloaded from The Cancer Genome Atlas (TCGA) database and 2,567 cuproptosis-related lncRNAs were obtained. A 10 cuproptosis-related-lncRNA prognostic signature was then constructed using the least absolute shrinkage and selection operator (LASSO) algorithm and Cox regression model and patients were divided into high- and low-risk groups. Kaplan-Meier analysis, receiver operating characteristic (ROC) curve, and a nomogram were employed to evaluate the predictive power of the signature. The immune characteristics and drug sensitivity were also investigated based on the signature. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to verify the risk model. In vitro experiments were conducted to validate the expression of the ten lncRNAs during cuproptosis.

Results

The high-risk group was associated with shorter overall survival (OS) time in COAD patients (p&lt;0.001). Multivariate Cox regression indicated that a high-risk score was an independent risk factor for poor prognosis (p&lt;0.001). ROC curve analysis was performed to confirm the validity of the signature (area under the curve (AUC) at 3 years: 0.879). Gene Ontology (GO) enrichment analysis revealed that the signature was highly correlated with the immune response in biological processes. The immune function, the score of the immune cells, and the expression of immune checkpoints were significantly different between the two risk groups. Three drugs, LAQ824, FH535, YM155, were found to be more sensitive in the high-risk group. Finally, the expression levels of the ten lncRNAs comprising the signature were tested by qRT-PCR.

Conclusion

A ten-cuproptosis-related lncRNA signature was constructed that provided promising insights into personalized prognosis and drug selection among COAD patients.

Linc00883 affects colorectal cancer through miR-577/FKBP14 axis: a novel mechanism for regulating colorectal cancer cell proliferation, invasion, and migration

Long non-coding RNAs (lncRNAs) are relevant to the development of human cancers. Here, we aimed to investigate the role and mechanism of Linc00883 in the proliferation, invasion, and migration of colorectal cancer (CRC) cells. CRC cell lines SW480 and LoVo were applied as in vitro models in this study. Quantitative real-time PCR was applied to measure Linc00883, miR-577, and FKBP14 expressions. Cell Counting Kit-8, transwell, and wound-healing assays were carried out to confirm the function of Linc00883. Western blot was applied to detect the protein levels of the epithelial-mesenchymal transition-related proteins E-cadherin, vimentin, fibronectin, and α-SMA. RNA immunoprecipitation (RIP) and RNA pull-down experiments were performed to confirm the relationship between Linc00883 and miR-577. Linc00883 expression was elevated in CRC tissues and cells, and the patients with high expression of Linc00883 were related to a low survival rate and prone to distant metastasis. Moreover, we corroborated that Linc00883 and miR-577, miR-577 and FKBP14 are bound to each other. Linc00883 was negatively correlated with miR-577, and miR-577 was also negatively correlated with FKBP14. Furthermore, interference with Linc00883 restrained the proliferation, invasion, and migration of CRC cells through the miR-577/FKBP14 axis. In vivo studies also clarified that Linc00883 facilitated the growth of CRC tumors and the epithelial-mesenchymal transition (EMT) of CRC. Our results demonstrated that Linc00883 facilitated the proliferation, invasion, and migration of CRC cells by regulating the miR-577/FKBP14 axis.

The Emerging role of EMT-related lncRNAs in therapy resistance and their application as biomarkers

Cancer is the world's second largest cause of death. The most common cancer treatments are surgery, radiation therapy, and chemotherapy. Drug resistance, epithelial-to-mesenchymal transition (EMT), and metastasis are all pressing issues in cancer therapy today. Increasing evidence showed that drug-resistant and EMT are co-related with each other. Indeed, drug-resistant cancer cells possess enhanced EMT and invasive ability. Recent researches have demonstrated lncRNAs (long noncoding RNAs) are noncoding transcripts, which play an important role in the regulation of EMT, metastasis, and drug resistance in different cancers. However, the relationships among lncRNAs, EMT, and drug resistance are still unclear. These effects could be exerted via several signaling pathways such as TGF-β, PI3K-AKT, and Wnt/β-catenin. Identifying the crucial regulatory roles of lncRNAs in these pathways and processes leads to the development of novel targeted therapies. We review the key aspects of lncRNAs associated with EMT and therapy resistance. We focus on the crosstalk between lncRNAs and molecular signaling pathways affecting EMT and drug resistance. Moreover, each of the mentioned lncRNAs could be used as a potential diagnostic, prognostic, and therapeutic biomarker for cancer. Although, there are still many challenges to investigate lncRNAs for clinical applications.

A Novel Ferroptosis-Related lncRNAs Signature Predicts Clinical Prognosis and Is Associated With Immune Landscape in Pancreatic Cancer

Pancreatic cancer is one of the most lethal malignancies and currently therapies are severely lacking. In this study, we aimed to establish a novel ferroptosis-related lncRNAs signature to predict the prognosis of patients with pancreatic cancer and evaluate the predictive abilities of candidate lncRNAs. According to The Cancer Genome Atlas (TCGA) database, a total of 182 patients with pancreatic cancer were included in our study. Ferroptosis-related lncRNAs were screened by Pearson correlation analysis with 60 reported ferroptosis-related genes. Through univariate, least absolute shrinkage and selection operator (LASSO) regression and multivariate regression analyses, a novel signature based on five ferroptosis-related lncRNAs(ZNF236-DT, CASC8, PAN3-AS1, SH3PXD2A-AS1, LINP1) was constructed. Risk-related differentially expressed genes (DEGs) were subjected to enrichment analyses for Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The results revealed that immune cell infiltration, immune-related functions and checkpoints were factors to affect prognoisis of pancreatic cancer. In summary, we identified the prognostic ferroptosis-related lncRNAs(ZNF236-DT, CASC8, PAN3-AS1, SH3PXD2A-AS1, LINP1) in pancreatic cancer and these lncRNAs may serve as therapeutic targets for pancreatic cancer.

Expression analysis and function of mitochondrial genome-encoded microRNAs

MicroRNAs play a significant role in nuclear and mitochondrial anterograde and retrograde signaling. Most of the miRNAs found inside mitochondria are nuclear genome encoded, with few mitochondrial genome encoded non-coding RNAs have been reported. In this study, we have identified 13 mitochondrial genome-encoded microRNAs (mitomiRs), which were differentially expressed in breast cancer cell lines (MCF-7, MDA-MB-468, and MDA-MB-231), non-malignant breast epithelial cell line (MCF-10A), and normal and breast cancer tissue specimens. We found that mitochondrial DNA depletion and inhibition of mitochondrial transcription leads to reduced expression of mitomiRs in breast cancer cells. MitomiRs physically interact with Ago2, an RNA-induced silencing complex (RISC) protein, in the cytoplasm and inside mitochondria. MitomiRs regulate the expression of both nuclear and mitochondrial transcripts in breast cancer cells. We showed that mitomiR-5 targets PPARGC1A and regulates mtDNA copy number in breast cancer cells. MitomiRs identified in the present study may be a promising tool for expression and functional analysis in patients with a defective mitochondrial phenotype, including cancer and metabolic syndromes.

KRAS-related long noncoding RNAs in human cancers

KRAS is one of the most widely prevalent proto-oncogenes in human cancers. The constitutively active KRAS oncoprotein contributes to both tumor onset and cancer development by promoting cell proliferation and anchorage-independent growth in a MAPK pathway-dependent manner. The expression of microRNAs (miRNAs) and the KRAS oncogene are known to be dysregulated in various cancers, while long noncoding RNAs (lncRNAs) can act as regulators of the miRNAs targeting KRAS oncogene in different cancers and have gradually become a focus of research in recent years. In this review article, we summarize recent advances in the research on lncRNAs that have sponging effects on KRAS-targeting miRNAs as crucial mediators of KRAS expression in different cell types and organs. A deeper understanding of lncRNA function in KRAS-driven cancers is of major fundamental importance and will provide a valuable clinical tool for the diagnosis, prognosis, and eventual treatment of cancers.

Analysis of the prognostic significance and potential mechanisms of lncRNAs associated with m6A methylation in papillary thyroid carcinoma

BACKGROUND

m6A methylation-related long non-coding RNAs (lncRNAs) play a significant role in the progression of various tumors and can be used as prognostic markers. However, whether m6A-related lncRNAs also play the same function as prognostic markers in papillary thyroid carcinoma (PTC) remains unclear.

METHODS

Consensus cluster analysis was performed to divide PTC samples obtained from The Cancer Genome Atlas database into two clusters according to the expression of m6A-related lncRNAs. Then, the least absolute shrinkage and selection operator (LASSO) regression analysis was performed to create and verify a prognostic model. Furthermore, the relationship among risk scores, clusters, programmed death-ligand 1 (PD-L1), tumor microenvironment (TME), clinicopathological characteristics, immune infiltration, immune checkpoint, and tumor mutation burden (TMB) was analyzed. In addition, a nomogram was created, and subsequently, the drug sensitivity of lncRNAs in the prognostic model was analyzed. Finally, the relationship between these lncRNAs and prognosis in pan-cancer was investigated.

RESULTS

The prognosis, RAS, BRAF, M, and TME were found to be different in two clusters. The prognostic model included three lncRNAs: PSMG3-AS1, BHLHE40-AS1, and AC016747.3. The risk score was associated with clusters, PD-L1, tumor microenvironment, clinicopathological characteristics, immune cell infiltration, immune checkpoint, and TMB, and thus, risk score was confirmed as useful prognostic indicator. Differentially expressed lncRNAs are involved in many malignancies and can be identified as cancer prognostic makers.

CONCLUSION

According to our research, we can regard m6A-related lncRNAs involved in the procession of PTC as a biomarker of progression-free survival for PTC patients, and pan-cancer.

Natural products: Potential targets of TME related long non-coding RNAs in lung cancer

BACKGROUND

Lung cancer is a significant health concern worldwide due to high mortality and morbidity, despite the advances in diagnosis, treatment, and management. Recent experimental evidence from different models suggested long non-coding RNAs (lncRNAs) as major modulators of cancer stem cells (CSCs) in the tumor microenvironment (TME) to support metastasis and drug resistance in lung cancer. Evidence-based studies demonstrated that natural products interfere with TME functions.

PURPOSE OF STUDY

To establish lncRNAs of TME as novel targets of natural compounds for lung cancer management.

STUDY DESIGN

Current study used a combination of TME and lung CSCs, lncRNAs and enrichment and stemness maintenance, natural products and stem cell management, natural products and lncRNAs, natural products and targeted delivery as keywords to retrieve the literature from Scopus, Web of Science, PubMed, and Google Scholar. This study critically reviewed the current literature and presented cancer stem cells' ability in reprogramming lung TME.

RESULTS

This review found that TME related oncogenic and tumor suppressor lncRNAs and their signaling pathways control the maintenance of stemness in lung TME. This review explored natural phenolic compounds and found that curcumin, genistein, quercetin epigallocatechin gallate and ginsenoside Rh2 are efficient in managing lung CSCs. They modulate lncRNAs and their upstream mediators by targeting signaling and epigenetic pathways. This review also identified relevant nanotechnology-based phytochemical delivery approaches for targeting lung cancer.

CONCLUSION

By critical literature analysis, TME related lncRNAs were identified as potential therapeutic targets, aiming to develop natural product-based therapeutics to treat metastatic and drug-resistant lung cancers.

Identification of Tumor Microenvironment-Related Prognostic lncRNAs in Lung Adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is the most common type of lung cancer and is a severe threat to human health. Although many therapies have been applied to LUAD, the long-term survival rate of patients remains unsatisfactory. We aim to find reliable immune microenvironment-related lncRNA biomarkers to improve LUAD prognosis.

Methods

ESTIMATE analysis was performed to evaluate the degree of immune infiltration of each patient in TAGA LUAD cohort. Correlation analysis was used to identify the immune microenvironment-related lncRNAs. Univariate cox regression analysis, LASSO analysis, and Kaplan Meier analysis were used to construct and validate the prognostic model based on microenvironment-related lncRNAs.

Results

We obtained 1,178 immune microenvironment-related lncRNAs after correlation analysis. One hundred and eighty of them are independent prognostic lncRNAs. Sixteen key lncRNAs were selected by LASSO method. This lncRNA-based model successfully predicted patients’ prognosis in validation cohort, and the risk score was related to pathological stage. Besides, we also found that TP53 had the highest frequency mutation in LUAD, and the mutation of TP53 in the high-risk group, which was identified by our survival model, has a poor prognosis. lncRNA-mRNA co-expression network further suggested that these lncRNAs play a vital role in the prognosis of LUAD.

Conclusion

Here, we filtered 16 key lncRNAs, which could predict the survival of LUAD and may be potential biomarkers and therapeutic targets.

Long noncoding RNAs in cancer metastasis

Metastasis is a major contributor to cancer-associated deaths. It is characterized by a multistep process that occurs through the acquisition of molecular and phenotypic changes enabling cancer cells from a primary tumour to disseminate and colonize at distant organ sites. Over the past decade, the discovery and characterization of long noncoding RNAs (lncRNAs) have revealed the diversity of their regulatory roles, including key contributions throughout the metastatic cascade. Here, we review how lncRNAs promote metastasis by functioning in discrete pro-metastatic steps including the epithelial-mesenchymal transition, invasion and migration and organotrophic colonization, and by influencing the metastatic tumour microenvironment, often by interacting within ribonucleoprotein complexes or directly with other nucleic acid entities. We discuss well-characterized lncRNAs with in vivo phenotypes and highlight mechanistic commonalities such as convergence with the TGFβ-ZEB1/ZEB2 axis or the nuclear factor-κB pathway, in addition to lncRNAs with controversial mechanisms and the influence of methodologies on mechanistic interpretation. Furthermore, some lncRNAs can help identify tumours with increased metastatic risk and spur novel therapeutic strategies, with several lncRNAs having shown potential as novel targets for antisense oligonucleotide therapy in animal models. In addition to well-characterized examples of lncRNAs functioning in metastasis, we discuss controversies and ongoing challenges in lncRNA biology. Finally, we present areas for future study for this rapidly evolving field.

Deciphering the Long Non-Coding RNAs and MicroRNAs Coregulation Networks in Ovarian Cancer Development: An Overview

Non-coding RNAs are emergent elements from the genome, which do not encode for proteins but have relevant cellular functions impacting almost all the physiological processes occurring in eukaryotic cells. In particular, microRNAs and long non-coding RNAs (lncRNAs) are a new class of small RNAs transcribed from the genome, which modulate the expression of specific genes at transcriptional and posttranscriptional levels, thus adding a new regulatory layer in the flux of genetic information. In cancer cells, the miRNAs and lncRNAs interactions with its target genes and functional pathways are deregulated as a consequence of epigenetic and genetic alterations occurring during tumorigenesis. In this review, we summarize the actual knowledge on the interplay of lncRNAs with its cognate miRNAs and mRNAs pairs, which interact in coregulatory networks with a particular emphasis on the mechanisms underlying its oncogenic behavior in ovarian cancer. Specifically, we reviewed here the evidences unraveling the relevant roles of lncRNAs/miRNAs pairs in altered regulation of cell migration, angiogenesis, therapy resistance, and Warburg effect. Finally, we also discussed its potential clinical implications in ovarian cancer and related endocrine disease therapies.

Identification and Validation of Immune-Related lncRNA Signature as a Prognostic Model for Skin Cutaneous Melanoma

Purpose

Skin cutaneous melanoma (SKCM) is the most aggressive skin cancer that results in high morbidity and mortality rate worldwide. Immune-related long non-coding RNAs (IRlncRs) play an important role in regulating gene expression in tumors. Therefore, in this study, we aimed to identify IRlncRs signature that could predict prognosis and therapeutic targets for melanoma irrespective of the gene expression levels.

Methods

RNA-sequencing data were obtained from The Cancer Genome Atlas (TCGA). IRlncRs were identified using co-expression analysis and recognized using univariate analysis. The impact of IRlncRs on survival was analyzed using a modified least absolute shrinkage and selection operator (Lasso) regression model. A 1-year survival receiver operating characteristic curve was constructed, and the area under the curve was calculated to identify the optimal cut-off point to distinguish between high and low-risk groups in patients with SKCM. Furthermore, integrative analysis was performed to identify the impact of clinicopathological features, chemotherapeutic treatment, tumor-infiltrating immune cells, and mutant genes on survival.

Results

A total of 28 IRlncRs significantly associated with survival were identified. Seventeen IRlncRs pairs were used to build a survival risk model that could be used to distinguish between low and high-risk groups. The high-risk group was negatively associated with tumor-infiltrating immune cells and had a higher half inhibitory centration for chemotherapeutic agents such as cisplatin and vinblastine. Additionally, the high-risk group had a positive correlation with the expression of specific mutant genes such as BRAF and KIT.

Conclusion

Our findings demonstrate that some IRlncRs have a significant correlation with survival and therapeutic targets for SKCM patients and may provide new insight into the clinical diagnosis and treatment strategies for SKCM patients.

Long noncoding RNA LMO7DN inhibits cell proliferation by regulating the cell cycle in lung adenocarcinoma

In our previous study, we reported that the long noncoding RNA, LMO7 downstream neighbor (LMO7DN), has a strong prognostic value in lung adenocarcinoma (LUAD). In this study, we further investigated the role of LMO7DN in LUAD progression. LMO7DN was found to be expressed at low levels in LUAD tissues, and its high expression predicted good prognosis. Bioinformatics analysis indicated that LMO7DN was closely associated with the cell cycle. Furthermore, we found that cell proliferation was significantly enhanced following knockdown of LMO7DN, and the number of cells in the G2/M phase was markedly decreased, whereas there was no change in apoptosis. Thus, LMO7DN inhibits cell proliferation by affecting the cell cycle and is of significant prognostic value in LUAD.

m6A-Related lncRNAs Are Potential Biomarkers for the Prognosis of Metastatic Skin Cutaneous Melanoma

Background: The incidence of skin cutaneous melanoma (SKCM) has risen more rapidly than any other solid tumor in the past few decades. The median survival for metastatic melanoma is only six to nine months and the 5°years survival rate of patients with conventional therapy is less than 5%. Our aim was to reveal the potential molecular mechanism in m6A modification of lncRNA and provide candidate prognostic biomarkers for metastatic SKCM.

Methods: lncRNAs expression level was obtained by re-annotation in TCGA and CCLE datasets. m6A-related lncRNAs were selected though correlation analysis. Univariate cox regression analysis was used to screen out independent prognostic factors. LASSO Cox regression was performed to construct an m6A-related lncRNA model (m6A-LncM). Univariate survival analysis and ROC curve were used to assess the prognostic efficacy of this model and candidate lncRNAs. Enrichment analysis was used to explore the candidate genes’ functions.

Results: We obtained 1,086 common m6A-related lncRNAs after Pearson correlation analysis in both two datasets. 130 out of the 1,086 lncRNAs are independent prognostic factors. 24 crucial lncRNAs were filtered after LASSO Cox regression analysis. All the m6A-LncM and the 24 lncRNAs were related to overall survival. Stratified survival analysis of m6A-LncM showed that the model retains its prognostic efficacy in recurrence, radiation therapy and other subgroups. Enrichment analysis also found that these lncRNAs were immune associated.

Conclusion: Here, we obtained 24 crucial lncRNAs that may be potential biomarkers to predict survival of metastatic SKCM and may provide a new insight to improve the prognosis of it.

Roles of Non-Coding RNAs in Cervical Cancer Metastasis

Metastasis remains to be a huge challenge in cancer therapy. The mechanism underlying cervical cancer metastasis is not well understood and needs to be elucidated. Recent studies have highlighted the diverse roles of non-coding RNAs in cancer progression and metastasis. Increasing numbers of miRNAs, lncRNAs and circRNAs are found to be dysregulated in cervical cancer, associated with metastasis. They have been shown to regulate metastasis through regulating metastasis-related genes, epithelial-mesenchymal transition, signaling pathways and interactions with tumor microenvironment. Moreover, miRNAs can interact with lncRNAs and circRNAs respectively during this complex process. Herein, we review literatures up to date involving non-coding RNAs in cervical cancer metastasis, mainly focus on the underlying mechanisms and highlight the interaction network between miRNAs and lncRNAs, as well as circRNAs. Finally, we discuss the therapeutic prospects.

RNA-biology ruling cancer progression? Focus on 3'UTRs and splicing

The protein-coding regions of mRNAs have the information to make proteins and hence have been at the center of attention for understanding altered protein functions in disease states, including cancer. Indeed, the discovery of genomic alterations and driver mutations that change protein levels and/or activity has been pivotal in our understanding of cancer biology. However, to better understand complex molecular mechanisms that are deregulated in cancers, we also need to look at non-coding parts of mRNAs, including 3'UTRs (untranslated regions), which control mRNA stability, localization, and translation efficiency. Recently, these rather overlooked regions of mRNAs are gaining attention as mounting evidence provides functional links between 3'UTRs, protein functions, and cancer-related molecular mechanisms. Here, roles of 3'UTRs in cancer biology and mechanisms that result in cancer-specific 3'-end isoform variants will be reviewed. An increased appreciation of 3'UTRs may help the discovery of new ways to explain as of yet unknown oncogene activation and tumor suppressor inactivation cases in cancers, and provide new avenues for diagnostic and therapeutic applications.

Long Non-Coding RNA PCAT6 Induces M2 Polarization of Macrophages in Cholangiocarcinoma via Modulating miR-326 and RhoA-ROCK Signaling Pathway

LncRNAs can act crucial roles in multiple tumors including cholangiocarcinoma (CCA). M2 polarization of macrophages is crucial for their biological roles in immunologic tolerance, which is able to induce tumorigenesis. Given that increasing evidence have suggested that lncRNAs could participate in modulating immune cell differentiation and function. Our current study was aimed to identify the underlying mechanism of lncRNA prostate cancer-associated transcript 6 (PCAT6) in CCA progression via regulating M2 macrophage polarization. PCAT6 has been reported as an oncogene in many cancers. In our work, we observed increased expression of PCAT6 in CCA patients. PCAT6 expression in various types of immune cells derived from CCA patients was tested by quantitative real-time PCR (qRT-PCR). It was revealed that PCAT6 was highly expressed in macrophages, which indicated that PCAT6 might regulate the function of macrophages to promote CCA progression. Then, via establishing CCA xenograft mouse model, we found loss of PCAT6 obviously triggered the immune response and reduced the in vivo tumor growth. In addition, overexpression of PCAT6 led to the M2 polarization of THP-1-differentiated macrophages. Moreover, miR-326 was predicted and proved as a target for PCAT6. In addition, down-regulation of PCAT6 repressed M2 polarization of macrophages, which was reversed by miR-326 inhibitors. The increase of PCAT6 induced the accumulation of ROS, mitochondrial and metabolic dysfunction in macrophages and mimics of miR-326 exhibited an opposite process. RohA has been recognized as a significant regulator of immune cell function. In our current work, we observed that RohA function as a downstream target for miR-326. In conclusion, our study highlighted a significant role of PCAT6/miR-326/RohA in immune response of macrophages in CCA and indicated PCAT6 as a potential target of immunotherapy in CCA.

miRNA landscape in primary tumors and matched metastases in gastrointestinal stromal tumors

Aim: Gastrointestinal stromal tumor management is extremely challenging, particularly the metastatic disease. The underlying mechanism in metastasis spread remains largely unknown. We aimed to characterize miRNAs involved in the metastatic process in gastrointestinal stromal tumor. Material & methods: Eight primary tumors and 18 synchronous metastases were analyzed through miRNA Taqman arrays or assays. Results: miRNAs profiles revealed similar expression in primary site and metastases. Pair-wise correlation coefficient between primary tumor and metastases was significant for each patient (p < 0.0001 for all profiled patients). Conclusion: Our study, the largest including primary tumors and metastases so far performed, highlighted perpetuation of miRNAs features in metastatic lesions and that the primary origin appears to be the main determinant of the metastases miRNA profile.

Identification of lncRNA-mRNA Regulatory Module to Explore the Pathogenesis and Prognosis of Melanoma

Skin cutaneous melanoma (SKCM) is an aggressive form of skin cancer that results in high mortality rate worldwide. It is vital to discover effective prognostic biomarkers and therapeutic targets for the treatment of melanoma. Long non-coding RNA (lncRNA) has been verified to play an essential role in the regulation of gene expression in diseases and tumors. Therefore, it is significant to explore the function of lncRNAs in the development and progression of SKCM. In this paper, a set of differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) were first screened out using 471 cutaneous melanoma samples and 813 normal skin samples. Gene Ontology and KEGG pathway enrichment analysis were performed to obtain the significant function annotations and pathways of DEmRNAs. We also ran survival analysis on both DElncRNAs and DEmRNAs to identify prognostic-related lncRNAs and mRNAs. Next, a set of hub genes derived from protein-protein interaction (PPI) network analysis and lncRNA target genes screened from starbase-ENCORI database were integrated to construct a lncRNA-mRNA regulatory module, which includes 6 lncRNAs 4 target mRNAs. We further checked the capacity of these lncRNA and mRNA in the diagnosis of melanoma, and found that single lncRNA can effectively distinguish tumor and normal tissue. Moreover, we ran CMap analysis to select a list of small molecule drugs for SKCM, such as EGFR inhibitor AG-490, growth factor receptor inhibitor GW-441756 and apoptosis stimulant betulinic-acid, which have shown therapeutic effect in the treatment of melanoma.

Silencing long non-coding RNA H19 combined with paclitaxel inhibits nasopharyngeal carcinoma progression

PURPOSE

This study aimed to study the effect of long non-coding RNA (lncRNA) H19 on proliferation, apoptosis and chemosensitivity of nasopharyngeal carcinoma (NPC) cells.

METHODS

NP69 and HNE3, C666-1, SUNE1, 6-10B and 5-8F cell lines were selected to detect the expression of lncRNA H19 via RT-qPCR. LncRNA H19 was overexpressed or silenced for exploring the regulatory effect of lncRNA H19 in cell proliferation, clone formation, apoptosis and drug resistance through CCK-8, clone formation experiment and flow cytometry respectively. The tumorigenic effect of lncRNA H19 silencing was verified by xenograft tumor in nude mice. LncRNA H19 was significantly up-regulated in NPC cells.

RESULTS

Silencing lncRNA H19 inhibited the proliferation of NPC C666-1 cells and promoted apoptosis, while overexpression of lncRNA H19 promoted the proliferation of NPC C666-1 cells and inhibited apoptosis. Knockdown of lncRNA H19 in drug-resistant cells remarkably reduced their drug resistance, and overexpression of lncRNA H19 in parental cells significantly reduced their drug sensitivity. Silencing lncRNA H19 inhibits tumor growth in vivo, and silencing lncRNA H19 combined with paclitaxel can enhance tumor inhibition in vivo.

CONCLUSIONS

In NPC cells, lncRNA H19 was up-regulated, lncRNA H19 inhibited the proliferation and chemosensitivity of NPC cells, promoted apoptosis, and silencing lncRNA H19 combined with paclitaxel could enhance tumor inhibition in vivo.

Long Noncoding RNA LINC00460 Facilitates Colorectal Cancer Progression by Negatively Regulating miR-613

Background

Long-noncoding RNAs (lncRNAs) could exert a crucial effect on the development of human cancers, including CRC. However, the biological function and underlying mechanism of LINCRNA00460 in the development of CRC still need deeper exploration.

Materials and Methods

The expression of LINC00460 in CRC tissues and cell lines was assessed by qRT-PCR. Cell proliferation, migration, and invasion were measured by the respective cell counting Kit-8 (CCK-8), wound healing assay and transwell invasion assay. Cell apoptosis and caspase-3 activity were detected by flow cytometry and caspase-3 activity assay. The relationship between LINC00460 and miR-613 expression was explored by Dual-luciferase reporter assay. Protein expression was measured by Western blotting. In vivo tumour growth was evaluated using a xenograft model of nude mice.

Results

LINC00460 was markedly up-regulated in CRC tissues and cell lines compared to their corresponding controls, which was closely correlated with clinical stage, TNM (T) classification, nodal (N) classification, metastasis (M) classification, liver metastasis and pathological differentiation, and survival rate of CRC patients. Functionally, LINC00460 knockdown decreased the proliferative, migrative and invasive abilities, and enhanced apoptosis rates and caspase-3 activity in HT29 and LOVO cells. Mechanistic studies indicated that miR-613 was targeted by LINC00460, and SphK1 was targeted and inversely regulated by miR-613 in HT29 and LOVO cells. In vivo studies, LINC00460 knockdown attenuated tumour growth. MiR-613 downregulation and SphK1 upregulation in the CRC tissues, and LINC00460 expression levels were inversely correlated with miR-613 expression and positively correlated with the SphK1 mRNA expression. Overall, LINC00460 modulated cell proliferation, migration, invasion and sphingosine kinase 1 (SphK1) expression in HT29 and LOVO cells, at least in most part, by regulating miR‐613.

Conclusion

LINC00460 functions as a competing endogenous RNA to regulate SphK1 expression by sponging miR‐613 in CRC and provides a valuable therapeutic strategy for CRC patients.

A nuclear lncRNA Linc00839 as a Myc target to promote breast cancer chemoresistance via PI3K/AKT signaling pathway

Chemoresistance has become a leading cause of mortality in breast cancer patients and is one of the major obstacles for improving the clinical outcome. Long noncoding RNAs play important roles in breast cancer tumorigenesis and chemoresistance. However, the involvement and regulation of lncRNAs in breast cancer chemoresistance are not completely understood. Here, we reported that Linc00839 was localized in the nucleus and upregulated in chemoresistant breast cancer cells and tissues, and high level of Linc00839 was associated with a poor prognosis. Knockdown of Linc00839 significantly suppressed proliferation, invasion, and migration, sensitized cells to paclitaxel in vitro and inhibited transplant tumor development in vivo. Mechanistically, we found that Myc could directly bind to the promoter region of Linc00839 and activate its transcription. Furthermore, Linc00839 overexpression increased the expression of Myc and the RNA‐binding protein Lin28B and activated the PI3K/AKT signaling pathway. We also discovered that Lin28B positively interacted with Linc00839 and was upregulated in breast cancer tissues. Taken together, for the first time, we showed that Linc00839 was activated by Myc and promoted proliferation and chemoresistance in breast cancer through binding with Lin28B. These findings provide new insight into the regulatory mechanism of Linc00839 and propose a Myc/Linc00839/Lin28B feedback loop that could be used as a novel therapeutic target for breast cancer.

lncRNA PCBP1-AS1 Aggravates the Progression of Hepatocellular Carcinoma via Regulating PCBP1/PRL-3/AKT Pathway

Background

Hepatocellular carcinoma (HCC) is a very belligerent primary liver tumor with high metastatic potential. Aberrant expression of lncRNAs drives tumorous invasion and metastasis. Whether lncRNAs engage mechanisms of liver cancer metastasis remains largely unexplored.

Patients and Methods

We collected HCC tissues from the tumors and their adjacent normal samples in the Chinese population and analyzed the levels of lncRNAs by microarray analysis. The gain- and loss-of-function analysis demonstrated that PCBP1-AS1 accelerated tumorous growth and metastasis in vivo and in vitro. Moreover, we used RNA-pulldown assay to show that PCBP1-AS1 physically interacted with polyC-RNA-binding protein 1 (PCBP1); meanwhile, PCBP1-AS1 was indeed detected in RIP with the PCBP1 antibody. Mechanistically, we first explored the relationship between PCBP1‐AS1 and PCBP1 in HCC cell lines.

Results

Here we show that PCBP1-AS1, identified by microarray analysis on pre- and post-operative HCC plasma specimens, was highly expressed in human HCC, clinically verified as a prometastatic factor and markedly associated with poor prognosis in patients with hepatocellular carcinoma. PCBP1‐AS1 was negatively related with PCBP1 at the messenger RNA and protein expression levels. PCBP1-AS1 triggered PRL-3 and AKT in HCC tumor cells. Additionally, the double knockout of PCBP1 and PCBP1-AS1 abolished the PCBP1-AS1-induced PRL-3-AKT signalling pathway activation.

Conclusion

The upregulation of PCBP1-AS1 enhances proliferation and metastasis in HCC, thus regulating the PCBP1-PRL-3-AKT signalling pathway.

Long noncoding RNA KTN1-AS1 promotes head and neck squamous cell carcinoma cell epithelial-mesenchymal transition by targeting miR-153-3p

Aim: To explore the biological functions and clinicopathologic significance of the long noncoding RNA KTN1-AS1 in head and neck squamous cell carcinoma (HNSCC). Materials & methods: We assessed the effects of KTN1-AS1 and identified the target miRNA by bioinformatics analysis, luciferase reporter, RNA pull-down and RNA immunoprecipitation assays. The clinicopathologic features of KTN1-AS1 and its target miRNA were analyzed in HNSCC. Results:KTN1-AS1, a competing endogenous RNA, promoted cell proliferation, migration, invasion and epithelial-mesenchymal transition by sponging miR-153-3p in HNSCC. Dysregulation of SNAI1 and ZEB2 mediated the effect of KTN1-AS1 due to miR-153-3p exhaustion. The KTN1-AS1 and miR-153-3p combination can accurately diagnose HNSCC. Conclusion: The KTN1-AS1 and miR-153-3p combination could be a valuable diagnostic and prognostic predictor for HNSCC.

The long noncoding RNA LINC00341 suppresses colorectal carcinoma by preventing cell migration and apoptosis

Long noncoding RNAs (lncRNAs) are ubiquitous transcripts that play key roles in regulating gene expression at the levels of transcription, RNA processing, and translation. Aberrant expression and mutations of lncRNAs represent a driving force behind oncogenesis and development of tumours. However, most of the lncRNAs are still being undiscovered, and conclusive experimental evidence for their functional relevance continues to be lacking for most malignancies. We have found that lncRNA long intergenic non–protein‐coding RNA 341 (LINC00341) is aberrantly downregulated by microarray‐based screenings on nonmetastatic and metastatic colorectal carcinoma (CRC) specimens; LINC00341 is a novel long intergenic non–protein‐coding RNA with unknown functions. LINC00341 overexpression restricts tumour growth and promotes its apoptosis. Instead, LINC00341 silencing accelerates CRC cell proliferation and migration. RNA‐pulldown assay identifies LINC00341 physically binds to HMGB2 and stabilizes the localization of HMGB2 in the cytoplasm. Notably, LINC00341 knockdown leads to the shift of HMGB2 into nuclear, in which it triggers epithelial to mesenchymal transition (EMT) programming. Moreover, LINC00341 can also promote apoptosis.

Significance of the study

LncRNAs are ubiquitous transcripts that play key roles in regulating gene expression at the levels of transcription, RNA processing, and translation. Aberrant expression and mutations of lncRNAs represent a driving force behind oncogenesis and development of tumours. However, the function of lncRNA still needs further exploration. Our study has revealed a new noncoding RNA‐mediated regulatory network that highly likely protects colorectal carcinoma by preventing migration and apoptosis. The results will help further explore the molecular details about the progression of colorectal carcinoma and stimulate efforts to develop effective therapies.

Long non-coding RNA in bladder cancer

Bladder cancer (BC) is the ninth most common malignant disease and ranks fourteenth in cancer mortality worldwide. Moreover, among cancers, the incidence and mortality of BC in males increased to the 6th and 9th place, respectively. The overall survival (OS) declines dramatically as the cancer progresses, especially when urothelial cells transition from noninvasive to invasive. It is well known that epithelial cells can acquire invasive properties and a propensity to metastasize through the epithelial-to-mesenchymal transition (EMT) process in tumourigenesis and progression. However, the potential molecular mechanisms and key pathways are still unclear. As the sequencing technology advances, long non-coding RNAs (lncRNAs) have been proven to play an important role in regulating biological processes and cellular pathways. Here, we reviewed important lncRNAs, such as H19, UCA1 and MALAT1, that participate in the malignant phenotype of BC and regulate EMT signalling networks in the invasion-metastasis cascade during BC development. We further discuss MALAT1, PCAT-1 and SPRY4-IT1, and also urine and blood exosomal H19 and PTENP as potential noninvasive biomarkers. Moreover, antisense oligonucleotides (ASOs) and a double-stranded DNA plasmid (BC-819) have been designed for use in preclinical cancer models and clinical trials in patients. Therefore, the results of investigations have gradually prompted the utility of lncRNAs.

RETRACTED: lncRNA RMST Enhances DNMT3 Expression through Interaction with HuR

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the editors and the corresponding author (Yin-Yuan Mo). Concerns regarding potentially duplicated western blots in Figures 2I and 3I were raised by readers on PubPeer (https://pubpeer.com/publications/64075911BAD21941D78C27FD3B8DB3#16), and the authors contacted the editorial office with the original blots to issue a correction. Following the correction of the article, the authors provided additional raw data to address further concerns raised by a reader. Given multiple inconsistencies in file labeling and post-acquisition processing, the editors have lost faith in the findings presented in the article. The retraction notice email was undeliverable to the following authors: Chao Ni, Pratirodh Koirala, Wei Zhang, and Wan-Xin Peng.

Mutant p53 on the Path to Metastasis

Metastasis contributes to the vast majority of cancer-related mortality. Regulatory mechanisms of the multistep invasion-metastasis cascade are being unraveled. TP53 is the most frequently mutated gene across human cancers. Accumulating evidence has shown that mutations of TP53 not only lead to loss of function or dominant negative effects, but also promotes a gain of function. Specifically, gain of function mutant p53 promotes cancer cell motility, invasion, and metastasis. Here, we summarize the mechanisms and functions of mutant p53 that foster metastasis in different types of cancers. We also discuss the prognostic value of mutant p53 and current status of therapeutic strategies targeting mutant p53. Future studies will shed light on discovering novel mechanisms of mutant p53-driven cancer metastasis and developing innovative therapeutics to improve clinical outcomes in patients harboring p53 mutations.

LncRNA RPPH1 promotes colorectal cancer metastasis by interacting with TUBB3 and by promoting exosomes-mediated macrophage M2 polarization

Metastasis is a well-known poor prognostic factor in cancer. However, the mechanisms how long non-coding RNAs (lncRNAs) regulate metastasis in colorectal cancer (CRC) remain largely unknown. Besides, tumor-associated macrophages (TAMs) play an important role in tumor progression, yet the contribution of lncRNA-mediated crosstalk between TAMs and CRC cells to tumor progression is not well understood. In this study, we report that lncRNA RPPH1 was significantly upregulated in CRC tissues, and the RPPH1 overexpression was associated with advanced TNM stages and poor prognosis. RPPH1 was found to promote CRC metastasis in vitro and in vivo. Mechanistically, RPPH1 induced epithelial–mesenchymal transition (EMT) of CRC cells via interacting with β-III tubulin (TUBB3) to prevent its ubiquitination. Furthermore, CRC cell-derived exosomes transported RPPH1 into macrophages which mediate macrophage M2 polarization, thereby in turn promoting metastasis and proliferation of CRC cells. In addition, exosomal RPPH1 levels in blood plasma turned out to be higher in treatment-naive CRC patients but lower after tumor resection. Compared to CEA and CA199, exosomal RPPH1 in CRC plasma displayed a better diagnostic value (AUC = 0.86). Collectively, RPPH1 serves as a potential therapeutic and diagnostic target in CRC.

Overexpression of long non-coding RNA LINC00982 suppresses cell proliferation and tumor growth of papillary thyroid carcinoma through PI3K-ATK signaling pathway

Long non-coding RNAs (lncRNAs) have been widely reported that involved in human cancers, including papillary thyroid carcinoma (PTC). The present study aims to investigate the biological role of LINC00982 in PTC. The mRNA expression of LINC00982 in human PTC tissues was detected using qPCR. Moreover, Kaplan-Meier method was performed to analyze the internal relevance between LINC00982 expression and overall survival (OS) rate of patients with PTC. In addition, gain- and loss-of-functions assays were performed to detect the effects of LINC00982 on the cell proliferation and migration in PTC cells. Furthermore, western blot assay was used to measure the alteration expression levels of apoptosis relative proteins and the relative protein involved phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway. Finally, a xenograft model was used to analyze the antitumor role of LINC00982 in vivo Here, we found that LINC00982 was decreased in human PTC tissues. Patients with decreased LINC00982 expression levels had a reduced OS (P=0.0019) compared with those with high LINC00982 expression levels. Overexpression of LINC00982 suppressed the proliferation and migration of BHT101 and B-CPAP cells and promoted cell apoptosis. Knockdown of LINC00982 promoted the proliferation and migration of BHT101 and B-CPAP cells and induced cell apoptosis. Moreover, in vivo assay showed that overexpression of LINC00982 could suppress the growth of PTC. Finally, LINC00982 could regulate the activity of PI3K/AKT signaling pathway in vitro and in vivo Taken together, our findings demonstrated that overexpression of LINC00982 could suppress cell proliferation and induce cell apoptosis by regulating PI3K/AKT signaling pathway in PTC.

Long Non-coding RNA CASC2 Enhances the Antitumor Activity of Cisplatin Through Suppressing the Akt Pathway by Inhibition of miR-181a in Esophageal Squamous Cell Carcinoma Cells

Background: Long non-coding RNA CASC2 (lncRNA CASC2) has been found to be down-regulated in esophageal squamous cell carcinoma (ESCC). However, the effect of CASC2 on cisplatin-treated ESCC was unclear. The present study aimed to evaluate the role of CASC2 in cisplatin-treated ESCC cells. Methods: The expression levels of CASC2 and miR-181a were detected by qRT-PCR. Cell viability was measured by MTT assay. The cytotoxicity effect was detected by lactate dehydrogenase (LDH) release assay. Cell apoptosis was tested by flow cytometry. The protein levels of protein kinase B (Akt) and p-Akt were detected by western blotting. Results: The results showed that CASC2 was low-expressed in ESCC cell lines. Overexpression of CASC2 enhanced the inhibitory effect of cisplatin on cell viability and promoted cisplatin-induced LDH release and apoptosis. We also found that miR-181a expression levels were increased in ESCC cell lines. MiR-181a inhibitor enhanced the antitumor activity of cisplatin, which was similar with the effect of CASC2. CASC2 directly interacted with miR-181a and inhibited the miR-181a expression. MiR-181a reversed the effects of CASC2 on antitumor activity of cisplatin. In addition, we also found that CASC2 suppressed the Akt pathway by inhibiting miR-181a. Conclusions: CASC2 promoted the antitumor activity of cisplatin through inhibiting Akt pathway via negatively regulating miR-181a in ESCC cells. The results provide a new insight for ESCC therapy.

Long noncoding RNA CRCMSL suppresses tumor invasive and metastasis in colorectal carcinoma through nucleocytoplasmic shuttling of HMGB2

Long noncoding RNAs (lncRNAs) are pervasive transcripts that play pivotal roles in regulating chromatin dynamics, gene and protein expression. Aberrant expression and mutations of lncRNAs represent a driving force behind tumor invasion and metastasis, making them attractive cancer targets. However, most of the lncRNAs are still being discovered and conclusive experimental evidence for their functional relevance is still lacking for most malignancies. In this study, a differentially expressed lncRNA, designated as lnc-CRCMSL, is identified by microarray-based screenings on non-metastatic and metastatic CRC specimens. Lnc-CRCMSL is verified as an anti-metastatic gene and negatively correlated with the poor prognosis of CRC patients. Lnc-CRCMSL overexpression restricts tumor growth and metastasis in vivo and in vitro. Instead, lnc-CRCMSL silencing accelerates CRC cell proliferation and migration. RNA-pulldown assay identifies high mobility group box 2 (HMGB2) as a downstream protein of lnc-CRCMSL. Mechanically, lnc-CRCMSL physically binds to HMGB2 and stabilizes the localization of HMGB2 in the cytoplasm. Notably, lnc-CRCMSL knockdown lead to the shift of HMGB2 into nuclear, in which it triggers epithelial to mesenchymal transition (EMT) programming. Importantly, lnc-CRCMSL controls the cytoplasmic retention of HMGB2 and attenuates the interaction between HMGB2 and OCT4 to suppress EMT. Treatment of leptomycin B (LMB), a potent and specific nuclear export inhibitor, counteracts lnc-CRCMSL-mediated suppression of aggressive phenotypes and EMT process by accumulating the nuclear HMGB2. CONCLUSION: Our data highlight the anti-metastatic role of lnc-CRCMSL in stabilizing HMGB2 through lncRNA-protein interactions in the cytoplasm, and suggest that targeting lnc-CRCMSL may represent a therapeutic opportunity for managing metastatic CRC.