Linc-RoR promotes MAPK/ERK signaling and confers estrogen-independent growth of breast cancer

Time-Resolved Profiling Reveals ATF3 as a Novel Mediator of Endocrine Resistance in Breast Cancer

Breast cancer is one of the leading causes of death for women worldwide. Patients whose tumors express Estrogen Receptor α account for around 70% of cases and are mostly treated with targeted endocrine therapy. However, depending on the degree of severity of the disease at diagnosis, 10 to 40% of these tumors eventually relapse due to resistance development. Even though recent novel approaches as the combination with CDK4/6 inhibitors increased the overall survival of relapsing patients, this remains relatively short and there is a urgent need to find alternative targetable pathways. In this study we profiled the early phases of the resistance development process to uncover drivers of this phenomenon. Time-resolved analysis revealed that ATF3, a member of the ATF/CREB family of transcription factors, acts as a novel regulator of the response to therapy via rewiring of central signaling processes towards the adaptation to endocrine treatment. ATF3 was found to be essential in controlling crucial processes such as proliferation, cell cycle, and apoptosis during the early response to treatment through the regulation of MAPK/AKT signaling pathways. Its essential role was confirmed in vivo in a mouse model, and elevated expression of ATF3 was verified in patient datasets, adding clinical relevance to our findings. This study proposes ATF3 as a novel mediator of endocrine resistance development in breast cancer and elucidates its role in the regulation of downstream pathways activities.

LncRNA regulation: New frontiers in epigenetic solutions to drug chemoresistance

Long-noncoding RNAs (lncRNAs) have been shown to participate in sensitizing or de-sensitizing cancer cells to chemical drugs during cancer therapeutics. Notably, a plethora of lncRNAs have been confirmed to be associated with epigenetic controllers and regulate histone protein modification or DNA methylation states in the process of gene transcription. This correlation between lncRNAs and epigenetic regulators can induce the expression of core genes to trigger drug resistance. In addition, epigenetic signatures are considered to be effective and attractive biomarkers for monitoring drug therapeutic effects because they are inheritable, dynamic, and reversible. Therefore, the regulatory mechanism between lncRNAs and epigenetic machinery can serve as a novel indicator and target to overcome or reverse drug resistance in cancer therapy. In this review, we also presented a curated selection of computational tools (including online databases and network analysis) in the area of epigenetics. A classic workflow for lncRNA expression network analysis is presented, providing guidance for non-bioinformaticians to identify significant correlation between lncRNAs and other biomolecules.

Connecting the Missing Dots: ncRNAs as Critical Regulators of Therapeutic Susceptibility in Breast Cancer

Whether acquired or de novo, drug resistance remains a significant hurdle in achieving therapeutic success in breast cancer (BC). Thus, there is an urge to find reliable biomarkers that will help in predicting the therapeutic response. Stable and easily accessible molecules such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are regarded as valuable prognostic biomarkers and therapeutic targets since they act as crucial regulators of the various mechanisms involved in BC drug resistance. Here, we reviewed the current literature on ncRNAs as mediators of resistance to systemic therapies in BC. Interestingly, upon integrating data results from individual studies, we concluded that miR-221, miR-222, miR-451, Urothelial Carcinoma Associated 1 (UCA1), and Growth arrest-specific 5 (GAS5) are strong candidates as prognostic biomarkers and therapeutic targets since they are regulating multiple drug resistance phenotypes in BC. However, further research around their clinical implications is needed to validate and integrate them into therapeutic applications. Therefore, we believe that our review may provide relevant evidence for the selection of novel therapeutic targets and prognostic biomarkers for BC and will serve as a foundation for future translational research in the field.

The implication of long non-coding RNAs in the diagnosis, pathogenesis and drug resistance of pancreatic ductal adenocarcinoma and their possible therapeutic potential

Pancreatic ductal adenocarcinoma (PDAC) is one of the lethal malignancies with the lowest median and overall survival rate among all human malignancies. The major problems with the PDAC are the late diagnosis, metastasis, and acquired resistance to chemotherapeutic agents in the clinic. Over the last decade, the long non-coding RNAs (lncRNAs) have been discovered and occupies a significantly large proportion of the human genome. Recent studies have proved that lncRNAs can play a crucial role in the majority of key cellular processes involved in the maintenance of cellular homeostasis by regulating various molecular mechanisms. The deregulation of lncRNAs has been associated with various chronic diseases including human malignancies. Several lncRNAs have tumor-specific expression making them an ideal and excellent target for designing the novel therapeutic strategies against human malignancies. We have discussed how lncRNA expression can be used for the diagnosis and prognosis of PDAC. The current review discusses the potential role and molecular mechanism of lncRNA in regulating the prominent hallmarks of cancer including abnormal growth, survival, metastasis, and drug-resistance in PDAC. Importantly, we also highlight the possible application of various therapeutic strategies including small interfering RNA, CRISPR-Cas9, antisense oligonucleotides, locked nucleic acid Gapmers, small molecules, aptamers, lncRNA promoter to target the lncRNA as a novel and viable options for treatment of PDAC.

Managing therapeutic resistance in breast cancer: from the lncRNAs perspective

Breast cancer (BC) is the most common female malignancy and the second leading cause of cancer-related death worldwide. In spite of significant advances in clinical management, the mortality of BC continues to increase due to the frequent occurrence of treatment resistance. Intensive studies have been conducted to elucidate the molecular mechanisms underlying BC therapeutic resistance, including increased drug efflux, altered drug targets, activated bypass signaling pathways, maintenance of cancer stemness, and deregulated immune response. Emerging evidence suggests that long noncoding RNAs (lncRNAs) are intimately involved in BC therapy resistance through multiple modes of action. Therefore, an in-depth understanding of the implication of lncRNAs in resistance to clinical therapies may improve the clinical outcome of BC patients. Here, we highlight the role and underlying mechanisms of lncRNAs in regulating BC treatment resistance with an emphasis on lncRNAs-mediated resistance in different clinical scenarios, and discuss the potential of lncRNAs as novel biomarkers or therapeutic targets to improve BC therapy response.

Relevance Function of Linc-ROR in the Pathogenesis of Cancer

Long non-coding RNAs (lncRNAs) are the key components of non-coding RNAs (ncRNAs) with a length of 200 nucleotides. They are transcribed from the so-called “dark matter” of the genome. Increasing evidence have shown that lncRNAs play an important role in the pathophysiology of human diseases, particularly in the development and progression of tumors. Linc-ROR, as a new intergenic non-protein coding RNA, has been considered to be a pivotal regulatory factor that affects the occurrence and development of human tumors, including breast cancer (BC), colorectal cancer (CRC), pancreatic cancer (PC), hepatocellular carcinoma (HCC), and so on. Dysregulation of Linc-ROR has been closely related to advanced clinicopathological factors predicting a poor prognosis. Because linc-ROR can regulate cell proliferation, apoptosis, migration, and invasion, it can thus be used as a potential biomarker for patients with tumors and has potential clinical significance as a therapeutic target. This article reviewed the role of linc-ROR in the development of tumors, its related molecular mechanisms, and clinical values.

Perspectives on the Role of Non-Coding RNAs in the Regulation of Expression and Function of the Estrogen Receptor

Estrogen receptors (ERs) comprise several nuclear and membrane-bound receptors with different tissue-specific functions. ERα and ERβ are two nuclear members of this family, whereas G protein-coupled estrogen receptor (GPER), ER-X, and Gq-coupled membrane estrogen receptor (Gq-mER) are membrane-bound G protein-coupled proteins. ERα participates in the development and function of several body organs such as the reproductive system, brain, heart and musculoskeletal systems. ERβ has a highly tissue-specific expression pattern, particularly in the female reproductive system, and exerts tumor-suppressive roles in some tissues. Recent studies have revealed functional links between both nuclear and membrane-bound ERs and non-coding RNAs. Several oncogenic lncRNAs and miRNAs have been shown to exert their effects through the modulation of the expression of ERs. Moreover, treatment with estradiol has been shown to alter the malignant behavior of cancer cells through functional axes composed of non-coding RNAs and ERs. The interaction between ERs and non-coding RNAs has functional relevance in several human pathologies associated with estrogen regulation, such as cancers, intervertebral disc degeneration, coronary heart disease and diabetes. In the current review, we summarize scientific literature on the role of miRNAs and lncRNAs on ER-associated signaling and related disorders.

Emerging Roles of Long Noncoding RNA Regulator of Reprogramming in Cancer Treatment

Despite numerous advances in cancer treatment, the global prevalence and cancer-related mortality remain high. Understanding tumor initiation and progression mechanisms are critical as it will lead to the development of interventions for improving the prognosis of cancer patients. The roles of long noncoding RNAs (lncRNAs) in cancer have attracted immense research interest. Growing evidence indicates that lncRNA regulator of reprogramming (linc-ROR), a well-studied RNA, regulates the progression of various cancers, such as lung cancer (LC), hepatocellular carcinoma (HCC), breast cancer (BC), colorectal cancer (CRC), pancreatic cancer (PC), papillary thyroid carcinoma (PTC), or esophageal squamous cell carcinoma (ESCC). linc-ROR promotes the proliferation, invasion, migration and chemoresistance of cancer cells. Herein, we reviewed current literature on the modulatory functions and mechanisms of linc-ROR in cancer development. We highlight new linc-ROR-related therapeutic strategies in cancer treatment.

Long Non-Coding RNAs in Drug Resistance of Breast Cancer

Breast cancer (BC) is the most common cancer and the leading cause of death in women. Advances in early diagnosis and therapeutic strategies have decreased the mortality of BC and improved the prognosis of patients to some extent. However, the development of drug resistance has limited the success rate of systemic therapies. Long non-coding RNAs (lncRNAs) are involved in drug resistance in BC via various mechanisms, which contribute to a complex regulatory network. In this review, we summarize the latest findings on the mechanisms underlying drug resistance modulated by lncRNAs in BC. In addition, we discuss the potential clinical applications of lncRNAs as targeted molecular therapy against drug resistance in BC.

Non-coding RNAs in cancer: platforms and strategies for investigating the genomic "dark matter"

The discovery of the role of non-coding RNAs (ncRNAs) in the onset and progression of malignancies is a promising frontier of cancer genetics. It is clear that ncRNAs are candidates for therapeutic intervention, since they may act as biomarkers or key regulators of cancer gene network. Recently, profiling and sequencing of ncRNAs disclosed deep deregulation in human cancers mostly due to aberrant mechanisms of ncRNAs biogenesis, such as amplification, deletion, abnormal epigenetic or transcriptional regulation. Although dysregulated ncRNAs may promote hallmarks of cancer as oncogenes or antagonize them as tumor suppressors, the mechanisms behind these events remain to be clarified. The development of new bioinformatic tools as well as novel molecular technologies is a challenging opportunity to disclose the role of the "dark matter" of the genome. In this review, we focus on currently available platforms, computational analyses and experimental strategies to investigate ncRNAs in cancer. We highlight the differences among experimental approaches aimed to dissect miRNAs and lncRNAs, which are the most studied ncRNAs. These two classes indeed need different investigation taking into account their intrinsic characteristics, such as length, structures and also the interacting molecules. Finally, we discuss the relevance of ncRNAs in clinical practice by considering promises and challenges behind the bench to bedside translation.

lncRNA- RP11-156p1.3, novel diagnostic and therapeutic targeting via CRISPR/Cas9 editing in hepatocellular carcinoma

We aim to characterize the expression of RNA panel in HCC. We assessed the expression of HCC-associated mRNA, miRNA and lncRNA network by real time PCR in sera and tissue samples. In a proof-of-principle approach, CRISPR cas9 mediated knock out for lncRNA- RP11-156p1.3 was performed in HEPG2 cell line to validate the role of the chosen RNA in HCC pathogenesis. The differential expression of RFTN1 mRNA, lncRNA- RP11-156p1.3 and miRNA-4764-5p was statistically different among the studied groups. After CRISPR cas9 mediated knockout of lncRNA- RP11-156p1.3 in HEPG2 cells, there was significant decrease in cell count and viability with reversal of the expression of the chosen RNAs. The chosen RNAs play a significant role in HCC pathogenesis and may be potential diagnostic and therapeutic targets.

CRISPR/Cas9 for overcoming drug resistance in solid tumors

OBJECTIVES

In this review, we focus on the application of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated nuclease 9 (Cas9), as a powerful genome editing system, in the identification of resistance mechanisms and in overcoming drug resistance in the most frequent solid tumors.

DATA ACQUISITION

Data were collected by conducting systematic searching of scientific English literature using specific keywords such as "cancer", "CRISPR" and related combinations.

RESULTS

The review findings revealed the importance of CRISPR/Cas9 system in understanding drug resistance mechanisms and identification of resistance-related genes such as PBRM1, SLFN11 and ATPE1 in different cancers. We also provided an overview of genes, including RSF1, CDK5, and SGOL1, whose disruption can synergize with the currently available drugs such as paclitaxel and sorafenib.

CONCLUSION

The data suggest CRISPR/Cas9 system as a useful tool in elucidating the molecular basis of drug resistance and improving clinical outcomes. Graphical abstract The mechanisms of CRISPR/Cas9-mediated genome editing and double-strand breaks (DSBs) repair.

Long Noncoding RNAs Involved in the Endocrine Therapy Resistance of Breast Cancer

Long noncoding RNAs (lncRNAs) are defined as RNAs longer than 200 nucleotides that do not encode proteins. Recent studies have demonstrated that numerous lncRNAs are expressed in humans and play key roles in the development of various types of cancers. Intriguingly, some lncRNAs have been demonstrated to be involved in endocrine therapy resistance for breast cancer through their own mechanisms, suggesting that lncRNAs could be promising new biomarkers and therapeutic targets of breast cancer. Here, we summarize the functions and mechanisms of lncRNAs related to the endocrine therapy resistance of breast cancer.

Emerging Roles of Estrogen-Regulated Enhancer and Long Non-Coding RNAs

Genome-wide RNA sequencing has shown that only a small fraction of the human genome is transcribed into protein-coding mRNAs. While once thought to be “junk” DNA, recent findings indicate that the rest of the genome encodes many types of non-coding RNA molecules with a myriad of functions still being determined. Among the non-coding RNAs, long non-coding RNAs (lncRNA) and enhancer RNAs (eRNA) are found to be most copious. While their exact biological functions and mechanisms of action are currently unknown, technologies such as next-generation RNA sequencing (RNA-seq) and global nuclear run-on sequencing (GRO-seq) have begun deciphering their expression patterns and biological significance. In addition to their identification, it has been shown that the expression of long non-coding RNAs and enhancer RNAs can vary due to spatial, temporal, developmental, or hormonal variations. In this review, we explore newly reported information on estrogen-regulated eRNAs and lncRNAs and their associated biological functions to help outline their markedly prominent roles in estrogen-dependent signaling.

Linc-ROR promotes the progression of breast cancer and decreases the sensitivity to rapamycin through miR-194-3p targeting MECP2

linc‐ROR is reported to be a potential biomarker of breast cancer, but the detailed mechanism of linc‐ROR‐mediated breast cancer regulation has not been fully studied. We aimed to explore how linc‐ROR affects proliferation, metastasis, and drug sensitivity in breast cancer. Cell lines in which linc‐ROR was overexpressed or knocked down were constructed, and the cell proliferation, colony formation, cell migration, and invasion abilities of these lines were explored. A CCK‐8 assay was performed to determine the sensitivity of the breast cancer cells to rapamycin. Next‐generation sequencing was conducted to explore the detailed regulatory mechanism of linc‐ROR; differentially expressed RNAs in the linc‐ROR‐overexpressing cell line compared with the negative control were screened out, and their target genes were chosen to perform Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes analysis, protein–protein interaction network analysis, and competing endogenous RNA (ceRNA) network analysis. The ceRNA mechanism of linc‐ROR for miR‐194‐3p, which targets MECP2, was determined through dual‐luciferase reporter assay, RT–qPCR, western blot, and rescue experiments. Finally, we found that linc‐ROR was upregulated in breast tumor tissues. linc‐ROR promoted the cell proliferation, colony formation, cell migration, and invasion of breast cancer and decreased the sensitivity of breast cancer cells to rapamycin. The overexpression of linc‐ROR triggered changes in the whole transcriptome of breast cancer cells, and a total of 85 lncRNAs, 414 microRNAs, 490 mRNAs, and 92 circRNAs were differentially expressed in the linc‐ROR‐overexpressing cell line compared with the negative control. Through a series of bioinformatic analyses, the ‘linc‐ROR/miR‐194‐3p/MECP2’ ceRNA regulatory axis was confirmed to be involved in the linc‐ROR‐mediated progression and drug sensitivity of breast cancer. In conclusion, linc‐ROR serves as an onco‐lncRNA in breast cancer and promotes the survival of breast cancer cells during rapamycin treatment by functioning as a ceRNA sponge for miR‐194‐3p, which targets MECP2.

Inferring LncRNA-disease associations based on graph autoencoder matrix completion

Accumulating studies have indicated that long non-coding RNAs (lncRNAs) play crucial roles in large amount of biological processes. Predicting lncRNA-disease associations can help biologist to understand the molecular mechanism of human disease and benefit for disease diagnosis, treatment and prevention. In this paper, we introduce a computational framework based on graph autoencoder matrix completion (GAMCLDA) to identify lncRNA-disease associations. In our method, the graph convolutional network is utilized to encode local graph structure and features of nodes for learning latent factor vectors of lncRNA and disease. Further, the inner product of lncRNA factor vector and disease factor vector is used as decoder to reconstruct the lncRNA-disease association matrix. In addition, the cost-sensitive neural network is utilized to deal with the imbalance between positive and negative samples. The experimental results show GAMLDA outperforms other state-of-the-art methods in prediction performance which is evaluated by AUC value, AUPR value, PPV and F1-score. Moreover, the case study shows our method is the effectively tool for potential lncRNA-disease prediction.

Identification of SOCS family members with prognostic values in human ovarian cancer

BACKGROUND

Suppressor of cytokine signaling (SOCS) family proteins regulate cytokine responses through inhibition of multiple signaling pathways. The expression profiles and prognostic significance of SOCS members in ovarian cancer (OC) patients still remains unclear. Here, we aimed to provide a comprehensive understanding of the prognostic values of SOCS family members in OC and to discover promising therapeutic targets for OC.

METHODS

We firstly analyzed the KEGG pathway enrichment to reveal the possible pathways associated with SOCS family. Next, we used public databases including cBioPortal, Human Protein Atlas and Oncomine to investigate genetic alterations and mRNA expression of SOCS family in OC patients. More importantly, we explored the prognostic value of each individual SOCS members in OC patients using Kaplan Meier plotter database.

RESULTS

SOCS family was markedly enriched in JAK-STAT signaling pathway. A high mutation rate in SOCSs was observed in patients with ovarian serous cancer (OSC). An increased mRNA expression of SOCS1 indicated a favorable overall survival (OS) in both OC and OSC patients, while increased SOCS5 and SOCS7 expressions were significantly associated with poorer OS. We also explored the diverse roles of SOCS members in OC patients with different clinicopathological features including grades, stages and therapies employed.

CONCLUSION

SOCS1, SOCS5 and SOCS7 may serve as prognostic biomarkers for OC patients. SOCS5 and SOCS7 may be potential therapeutic targets for OC treatment. Our results render novel insights into the association between SOCS family genes and OC development, and may highlight promising molecular targets for therapeutic interventions in OC patients.

The Role of Long Noncoding RNAs in Antiestrogen Resistance in Breast Cancer: An Overview and Update

As a standard treatment, endocrine therapy has dramatically enhanced the prognosis of patients with estrogen receptor (ER)-positive breast cancer, which accounts for nearly 70% of all breast cancers. Antiestrogen drugs such as tamoxifen and aromatase inhibitors are the standard treatment options for ERα-positive breast cancer. However, acquired antiestrogen resistance is still the leading cause of disease recurrence and progression. Evidence has shown that long noncoding RNAs (lncRNAs) play an essential role in the development of antiestrogen resistance in ER-positive breast cancer and can serve as biomarkers or potential therapeutic targets. This review highlights the role of lncRNAs in the development of antiestrogen resistance in breast cancer.

The network of non-coding RNAs and their molecular targets in breast cancer

Background

Non-coding RNAs are now recognized as fundamental components of the cellular processes. Non-coding RNAs are composed of different classes, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). Their detailed roles in breast cancer are still under scrutiny.

Main body

We systematically reviewed from recent literature the many functional and physical interactions of non-coding RNAs in breast cancer. We used a data driven approach to establish the network of direct, and indirect, interactions. Human curation was essential to de-convolute and critically assess the experimental approaches in the reviewed articles. To enrol the scientific papers in our article cohort, due to the short time span (shorter than 5 years) we considered the journal impact factor rather than the citation number.

The outcome of our work is the formal establishment of different sub-networks composed by non-coding RNAs and coding genes with validated relations in human breast cancer. This review describes in a concise and unbiased fashion the core of our current knowledge on the role of lncRNAs, miRNAs and other non-coding RNAs in breast cancer.

Conclusions

A number of coding/non-coding gene interactions have been investigated in breast cancer during recent years and their full extent is still being established. Here, we have unveiled some of the most important networks embracing those interactions, and described their involvement in cancer development and in its malignant progression.

Down-regulation of lncRNA LINC00152 Suppresses Gastric Cancer Cell Migration and Invasion Through Inhibition of the ERK/MAPK Signaling Pathway

Purpose

The aim of this study was to explore the regulatory role and mechanism of long noncoding RNA LINC00152 in gastric cancer (GC) cells.

Methods

LINC00152 expression in GC tissues and cells was detected by reverse transcription-polymerase chain reaction (qRT-PCR). MKN45 and MGC-803 cells were selected and assigned into different groups after transfection with si-LINC00152, activated ERK/MAPK signaling pathway (SA), or negative control. Cell proliferation, apoptosis, cycle, migration and invasion were assessed by CCK-8, flow cytometry, Transwell assay and Scratch test, respectively. Western blot analysis was conducted to detect the expression of E-cadherin, N-cadherin and ERK/MAPK signaling pathway protein.

Results

Compared with the normal tissues, higher expression of LINC00152 was found in GC tissues and LINC00152 was remarkably correlative with clinical stage and lymphatic metastasis. LINC00152 expression in GC cells was higher than that in GES-1 cells. Compared with the NC group, the cell proliferation rate, cells in G2/M phase, migration and invasion abilities as well as the expression of N-cadherin and p-ERK-1/2 were significantly decreased, and the expression of E-cadherin, cells in G0/G1 phase and cell apoptosis rate were significantly increased in the si-LINC00152-1 group. ERK/MAPK signaling pathway activator SA could reverse the biological role of LINC00152 in GC cells.

Conclusion

These results demonstrated that the interference of LINC00152 expression may inhibit the invasion and migration of GC cells by inhibiting the ERK/MAPK signaling pathway.

LncRNA LINP1 confers tamoxifen resistance and negatively regulated by ER signaling in breast cancer

Tamoxifen (TAM) is frequently used to treat patients with estrogen receptor-positive (ER+) breast cancer; however, the development of endocrine resistance represents a major impediment for successful treatment. Recent studies have demonstrated that long non-coding RNAs (lncRNAs) may serve critical roles in regulating endocrine resistance in breast cancer. In the present study, it was determined that the expression of lncRNA in nonhomologous end joining pathway 1 (LINP1) was increased in tamoxifen-resistant breast cancer cells, and that LINP1 knockdown significantly attenuated the tamoxifen resistance and viability of tamoxifen-resistant breast cancer cells in vitro and in vivo. LINP1 knockdown increased apoptosis in cells following treatment with tamoxifen. Furthermore, LINP1 overexpression resulted in increased cell mobility by regulating the EMT process. Mechanistically, LINP1 is a direct target of ER-mediated transcriptional repression, and both tamoxifen treatment and hormone deprivation increased the expression of LINP1. LINP1 overexpression was associated with downregulation of the levels of ER protein and attenuated the estrogen response, which is a pivotal contributing factor to anti-estrogen resistance. Taken together, the present study highlights the pivotal role of LINP1 in tamoxifen resistance, which may serve as a potential target to improve the effectiveness and efficacy of tamoxifen treatment in breast cancer.

Long Non-Coding RNA and Breast Cancer

Breast cancer, one of the most common diseases among women, is regarded as a heterogeneous and complicated disease that remains a major public health concern. Recently, owing to the development of next-generation sequencing technologies, long non-coding RNAs have received extensive attention. Numerous studies reveal that long non-coding RNAs are playing important roles in tumor development. Although the biological function and molecular mechanisms of long non-coding RNAs remain enigmatic, recent researchers have demonstrated that an array of long non-coding RNAs express abnormally in cancers, including breast cancer. Herein, we summarized the latest literature about long non-coding RNAs in breast cancer, with a particular focus on the multiple molecular roles of regulatory long non-coding RNAs that regulate cell proliferation, invasion, metastasis, and apoptosis.

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.

ERK1 indicates good prognosis and inhibits breast cancer progression by suppressing YAP1 signaling

The mitogen-activated protein kinase/extracellular signal-regulated (MAPK/ERK) pathway is a well-characterized signaling pathway during the development of various cancer types. ERK1 and ERK2, the two kinase effectors of MAPK cascade, exhibit high similarity. However, it is still unknown whether these two kinases are functionally different or in contrast functionally redundant during the development of breast cancer. We found that ERK1 expression levels were significantly lower in basal breast cancer compared with luminal breast cancer and normal breast tissues. RNA sequencing data suggested that ERK1 was associated with Hippo signaling pathway and cell proliferation in breast cancer cells. The gene set enrichment analysis (GSEA) further showed enrichment for YAP1 signaling pathway in breast cancer cell lines and tumors with low expression of ERK1. Silencing of ERK1 elevated YAP1 expression and TEAD activity in breast cancer cells. Additionally, ERK1 inhibited breast cancer cell proliferation via regulation of YAP1. The Kaplan-Meier analysis of data in patients with breast cancer suggested that, higher expression of ERK1 was associated with better prognosis, whereas, higher expression of ERK2 predicted poorer prognosis. These findings unveiled the role of ERK1 on regulation of YAP1 signaling pathway, indicating ERK1 as a negative regulator of breast cancer progression.

The molecular mechanisms of LncRNA-correlated PKM2 in cancer metabolism

Reprogrammed metabolism is an important hallmark of cancer cells. Pyruvate kinase (PK) is one of the major rate-limiting enzymes in glucose metabolism. The M2 isoform of PK (PKM2), is considered to be an important marker of metabolic reprogramming and one of the key enzymes. Recently, through the continuous development of genome-wide analysis and functional studies, accumulating evidence has demonstrated that long non-coding RNAs (LncRNAs) play vital regulatory roles in cancer progression by acting as either potential oncogenes or tumor suppressors. Furthermore, several studies have shown that up-regulation of PKM2 in cancer tissues is associated with LncRNAs expression and patient survival. Thus, scientists have begun to unveil the mechanism of LncRNA-associated PKM2 in cancer metabolic progression. Based on these novel findings, in this mini-review, we summarize the detailed molecular mechanisms of LncRNA related to PKM2 in cancer metabolism. We expect that this work will promote a better understanding of the molecular mechanisms of PKM2, and provide a profound potential for targeting PKM2 to treat tumors.

A Comprehensive Review on MAPK: A Promising Therapeutic Target in Cancer

The mitogen-activated protein kinase (MAPK) pathway is an important bridge in the switch from extracellular signals to intracellular responses. Alterations of signaling cascades are found in various diseases, including cancer, as a result of genetic and epigenetic changes. Numerous studies focused on both the homeostatic and the pathologic conduct of MAPK signaling; however, there is still much to be deciphered in terms of regulation and action models in both preclinical and clinical research. MAPK has implications in the response to cancer therapy, particularly the activation of the compensatory pathways in response to experimental MAPK inhibition. The present paper discusses new insights into MAPK as a complex cell signaling pathway with roles in the sustenance of cellular normal conduit, response to cancer therapy, and activation of compensatory pathways. Unfortunately, most MAPK inhibitors trigger resistance due to the activation of compensatory feed-back loops in tumor cells and tumor microenvironment components. Therefore, novel combinatorial therapies have to be implemented for cancer management in order to restrict the possibility of alternative pathway activation, as a perspective for developing novel therapies based on integration in translational studies.

LINC01133 inhibits breast cancer invasion and metastasis by negatively regulating SOX4 expression through EZH2

Mounting evidence highlights long non-coding RNAs (lncRNAs) as crucial regulators in multiple types of biological processes and contributing to tumourigenesis. LINC01133, located in chromosome 1q23.2, was a recently identified novel lncRNA with a length of 1154nt. It was involved in the development of colorectal cancer and non-small cell lung cancer. However, its clinical relevance, biological functions and potential molecular mechanism in breast cancer are still unclear. In this study, we found that the LINC01133 expression was significantly down-regulated in breast cancer samples and was associated with progression and poor prognosis of breast cancer. Further experiments demonstrated that overexpression of LINC01133 inhibited invasion and metastasis in breast cancer both in vitro and in vivo. Mechanistic investigations revealed that LINC01133 repressed SOX4 expression by recruiting EZH2 to SOX4 promoter. Moreover, rescue experiments further confirmed that LINC01133 functional acted as an anti-oncogene, at least partly, via repressing SOX4 in breast cancer. Taken together, these findings imply that LINC01133 could serve as a novel prognostic biomarker and potential therapeutic target for breast cancer.

LINC00346 promotes pancreatic cancer progression through the CTCF-mediated Myc transcription

Although multiple factors are known to contribute to pancreatic ductal adenocarcinoma (PDAC) progression, the role of long non-coding RNAs (lncRNAs) in PDAC remains largely unknown. In this study, we present data that long intergenic non-coding RNA 346 (LINC00346) functions as a promoting factor for PDAC development. We first show that LINC00346 is highly expressed in pancreatic tumor specimens as compared to normal pancreatic tissue based on interrogation of The Cancer Genome Atlas (TCGA) pancreatic adenocarcinoma dataset. Of significance, this upregulation of LINC00346 is associated with overall survival (OS) and disease-free survival (DFS), respectively. We further show that knockout (KO) of LINC00346 impairs pancreatic cancer cell proliferation, tumorigenesis, migration, and invasion ability. Importantly, these phenotypes can be restored by LINC00346 re-expression in KO cells (i.e., rescue experiment). RNA precipitation assays combined with mass spectrometry analysis indicate that LINC00346 interacts with CCCTC-binding factor (CTCF), a known transcriptional repressor of c-Myc. This interaction between LINC00346 and CTCF prevents the binding of CTCF to c-Myc promoter, relieving the CTCF-mediated repression of c-Myc. Thus, LINC00346 functions as a positive transcriptional regulator of c-Myc. Together, these results suggest that LINC00346 contributes to PDAC pathogenesis by activating c-Myc, and as such, LINC00346 may serve as a potential biomarker and therapeutic target for PDAC.

Chinese yam extract and adenosine attenuated LPS-induced cardiac dysfunction by inhibiting RAS and apoptosis via the ER-mediated activation of SHC/Ras/Raf1 pathway

PURPOSE

This study aimed to examine the effects of the Chinese yam extract and adenosine on lipopolysaccharide (LPS)-induced cardiac anomalies and the underlying mechanisms involved.

METHODS

Chinese yam extract [1630 mg/kg, intragastric (i.g.), 2 times/day] and adenosine (50 mg/kg, i.g., 2 times/day) were administered for 3 days, followed by the induction of sepsis by injecting LPS intraperitoneally [10 mg/kg, 2 h prior, intraperitoneally (i.p.)]. Also, estrogen receptor (ER)-unspecific antagonist Faslodex (ICI182,780, 0.5 mg/kg, i.p.) was administered 30 min before the treatments of Chinese yam extract or adenosine to evaluate whether the observed effects elicited by yam and adenosine were mediated via ERs. The heart function and the levels of pro-inflammatory cytokines, reversed mitogen-activated protein kinases (MAPKs), renin-angiotensin system (RAS), apoptosis markers, ER, and SHC/Ras/Raf1 were examined. The antagonistic effect of ICI182,780 (1 μM) and FTS (1 μM) against the Chinese yam extract (0.1 mg/ml) and adenosine (5 μM) in LPS (20 μg/ml, 24 h)-induced H9c2 cells was also investigated.

RESULTS

The Chinese yam extract and adenosine improved heart function, downregulated pro-inflammatory cytokines, reversed MAPK and RAS, transformed the apoptosis markers, and increased the expression of ER and SHC/Ras/Raf1 following LPS challenge. These effects could be blocked by ICI182,780. FTS could not block the expression of ER on the Chinese yam extract and adenosine interposed on LPS-induced H9c2 cells, demonstrating that ER might be the upstream signaling regulator of SHC/Ras/Raf1.

CONCLUSION

The Chinese yam extract and adenosine ameliorated LPS-induced cardiac contractility through the inhibition of RAS and apoptosis possibly via an ER-SHC/Ras/Raf1-dependent mechanism.

Parallels between artificial reprogramming and the biogenesis of cancer stem cells: Involvement of lncRNAs

Cellular identity is established and maintained by the interplay of cell type-specific transcription factors and epigenetic regulation of the genome. During development in vivo and differentiation in vitro, transitions from one cell type to the next are triggered by cell signaling events culminating in modifications of chromatin that render genes accessible or inaccessible to the transcriptional apparatus. In recent years it has become apparent that cellular identity is plastic, and technological reprogramming methods such as somatic cell nuclear transfer and induced pluripotency can yield reprogrammed cells that have been restored to a state of developmental potency. Long noncoding RNAs (lncRNAs) are untranslated functional RNA molecules that are intimately involved in the regulation of the chromatin of protein-coding genes. In fact, recent evidence shows that there are more lncRNA species in the cell than mRNA species and that most protein-coding genes are likely to be under epigenetic regulation mediated by lncRNAs. This review examines lncRNA function in reprogrammed pluripotent cells and cancer stem cells. Because cancer stem cells arise from normal cells, their biogenesis can be viewed as a reprogramming process that occurs in vivo, and parallels between artificial reprogramming and cancer stem cell biogenesis are discussed.

Application of CRISPR/Cas9 gene editing technique in the study of cancer treatment

In recent years, gene editing, especially that using clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9, has made great progress in the field of gene function. Rapid development of gene editing techniques has contributed to their significance in the field of medicine. Because the CRISPR/Cas9 gene editing tool is not only powerful but also has features such as strong specificity and high efficiency, it can accurately and rapidly screen the whole genome, facilitating the administration of gene therapy for specific diseases. In the field of tumor research, CRISPR/Cas9 can be used to edit genomes to explore the mechanisms of tumor occurrence, development, and metastasis. In these years, this system has been increasingly applied in tumor treatment research. CRISPR/Cas9 can be used to treat tumors by repairing mutations or knocking out specific genes. To date, numerous preliminary studies have been conducted on tumor treatment in related fields. CRISPR/Cas9 holds great promise for gene-level tumor treatment. Personalized and targeted therapy based on CRISPR/Cas9 will possibly shape the development of tumor therapy in the future. In this study, we review the findings of CRISPR/Cas9 for tumor treatment research to provide references for related future studies on the pathogenesis and clinical treatment of tumors.

Targeting the circBMPR2/miR-553/USP4 Axis as a Potent Therapeutic Approach for Breast Cancer

Emerging evidence suggests that circular RNAs (circRNAs) have crucial roles in various processes, including cancer development and progression. However, the functional roles of circRNAs in breast cancer remain to be elucidated. In this study, we identified a novel circRNA (named circBMPR2) whose expression was lower in breast cancer tissues with metastasis. Moreover, circBMPR2 expression was negatively associated with the motility of breast cancer cells and significantly downregulated in human breast cancer tissues. Functionally, we found that circBMPR2 knockdown effectively enhanced cell proliferation, migration, and invasion. Moreover, circBMPR2 knockdown promoted tamoxifen resistance of breast cancer cells through inhibiting tamoxifen-induced apoptosis, whereas circBMPR2 overexpression led to decreased tamoxifen resistance. Mechanistically, we demonstrated that circBMPR2 could abundantly sponge miR-553 and that miR-553 overexpression could attenuate the inhibitory effects caused by circBMPR2 overexpression. We also found that ubiquitin-specific protease 4 (USP4) was a direct target of miR-553, which functions as a tumor suppressor in breast cancer. Our findings demonstrated that circBMPR2 might function as a miR-553 sponge and then relieve the suppression of USP4 to inhibit the progression and tamoxifen resistance of breast cancer. Targeting this newly identified circRNA may help us to develop potential novel therapies for breast cancer patients.

FOXM1-Mediated LINC-ROR Regulates the Proliferation and Sensitivity to Sorafenib in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-associated death worldwide. Indeed, despite the benefit of sorafenib in the treatment of some patients with HCC, the majority of these patients have a poor response to or intolerance of sorafenib, resulting in further tumor progression. Exploring the mechanisms underlying sorafenib resistance is essential to the treatment of HCC. Long noncoding RNAs (lncRNAs) are known as participants in tumorigenesis. In this study, we identified that long intergenic non-protein coding RNA, regulator of reprogramming (LINC-ROR), was upregulated in HCC cell lines, which was transcriptionally activated by FOXM1. Furthermore, the sponging of miR-876-5p by LINC-ROR released FOXM1, thereby forming a positive-feedback loop. Additionally, we demonstrated that upregulation of both FOXM1 and LINC-ROR impaired the sensitivity to sorafenib in HCC cells. The role of this feedback loop was demonstrated by rescue assays. These results revealed a novel molecular feedback loop between LINC-ROR and FOXM1 and elucidated their functions in sorafenib sensitivity of HCC cell lines.

Time resolved gene expression analysis during tamoxifen adaption of MCF-7 cells identifies long non-coding RNAs with prognostic impact

Acquired tamoxifen resistance is a persistent problem for the treatment of estrogen receptor positive, premenopausal breast cancer patients and predictive biomarkers are still elusive. We here analyzed gene expression changes in a cellular model to identify early and late changes upon tamoxifen exposure and thereby novel prognostic biomarkers. Estrogen receptor positive MCF-7 cells were incubated with 4OH-tamoxifen (10 nM) and gene expression analyzed by array hybridization during 12 weeks. Array results were confirmed by nCounter- and qRT-PCR technique. Pathway enrichment analysis revealed that early responses concerned mainly amine synthesis and NRF2-related signaling and evolved into a stable gene expression pattern within 4 weeks characterized by changes in glucuronidation-, estrogen metabolism-, nuclear receptor- and interferon signaling pathways. As a large number of long non coding RNAs was subject to regulation, we investigated 5 of these (linc01213, linc00632 linc0992, LOC101929547 and XR_133213) in more detail. From these, only linc01213 was upregulated but all were less abundant in estrogen-receptor negative cell lines (MDA-MB 231, SKBR-3 and UACC3199). In a web-based survival analysis linc01213 and linc00632 turned out to have prognostic impact. Linc01213 was investigated further by plasmid-mediated over-expression as well as siRNA down-regulation in MCF-7 cells. Nevertheless, this had no effect on proliferation or expression of tamoxifen regulated genes, but migration was increased. In conclusion, the cellular model identified a set of lincRNAs with prognostic relevance for breast cancer. One of these, linc01213 although regulated by 4OH-tamoxifen, is not a central regulator of tamoxifen adaption, but interferes with the regulation of migration.

Autophagy-Modulating Long Non-coding RNAs (LncRNAs) and Their Molecular Events in Cancer

Cancer is a global threat of health. Cancer incidence and death is also increasing continuously because of poor understanding of diseases. Although, traditional treatments (surgery, radiotherapy, and chemotherapy) are effective against primary tumors, death rate is increasing because of metastasis development where traditional treatments have failed. Autophagy is a conserved regulatory process of eliminating proteins and damaged organelles. Numerous research revealed that autophagy has dual sword mechanisms including cancer progressions and suppressions. In most of the cases, it maintains homeostasis of cancer microenvironment by providing nutritional supplement under starvation and hypoxic conditions. Over the past few decades, stunning research evidence disclosed significant roles of long non-coding RNAs (lncRNAs) in the regulation of autophagy. LncRNAs are RNA containing more than 200 nucleotides, which have no protein-coding ability but they are found to be expressed in most of the cancers. It is also proved that, autophagy-modulating lncRNAs have significant impacts on pro-survival or pro-death roles in cancers. In this review, we highlighted the recently identified autophagy-modulating lncRNAs, their signaling transduction in cancer and mechanism in cancer. This review will explore newly emerging knowledge of cancer genetics and it may provide novel targets for cancer therapy.

Adipocyte-derived IL-6 and leptin promote breast Cancer metastasis via upregulation of Lysyl Hydroxylase-2 expression

BACKGROUND

Adipocytes make up the major component of breast tissue, accounting for 90% of stromal tissue. Thus, the crosstalk between adipocytes and breast cancer cells may play a critical role in cancer progression. Adipocyte-breast cancer interactions have been considered important for the promotion of breast cancer metastasis. However, the specific mechanisms underlying these interactions are unclear. In this study, we investigated the mechanisms of adipocyte-mediated breast cancer metastasis.

METHODS

Breast cancer cells were cocultured with mature adipocytes for migration and 3D matrix invasion assays. Next, lentivirus-mediated loss-of-function experiments were used to explore the function of lysyl hydroxylase (PLOD2) in breast cancer migration and adipocyte-dependent migration of breast cancer cells. The role of PLOD2 in breast cancer metastasis was further confirmed using orthotopic mammary fat pad xenografts in vivo. Clinical samples were used to confirm that PLOD2 expression is increased in tumor tissue and is associated with poor prognosis of breast cancer patients. Cells were treated with cytokines and pharmacological inhibitors in order to verify which adipokines were responsible for activation of PLOD2 expression and which signaling pathways were activated in vitro.

RESULTS

Gene expression profiling and Western blotting analyses revealed that PLOD2 was upregulated in breast cancer cells following coculture with adipocytes; this process was accompanied by enhanced breast cancer cell migration and invasion. Loss-of-function studies indicated that PLOD2 knockdown suppressed cell migration and disrupted the formation of actin stress fibers in breast cancer cells and abrogated the migration induced by following coculture with adipocytes. Moreover, experiments performed in orthotopic mammary fat pad xenografts showed that PLOD2 knockdown could reduce metastasis to the lung and liver. Further, high PLOD2 expression correlated with poor prognosis of breast cancer patients. Mechanistically, adipocyte-derived interleukin-6 (IL-6) and leptin may facilitate PLOD2 upregulation in breast cancer cells and promote breast cancer metastasis in tail vein metastasis assays. Further investigation revealed that adipocyte-derived IL-6 and leptin promoted PLOD2 expression through activation of the JAK/STAT3 and PI3K/AKT signaling pathways.

CONCLUSIONS

Our study reveals that adipocyte-derived IL-6 and leptin promote PLOD2 expression by activating the JAK/STAT3 and PI3K/AKT signaling pathways, thus promoting breast cancer metastasis.

Estrogen receptor β upregulated by lncRNA-H19 to promote cancer stem-like properties in papillary thyroid carcinoma

Estrogen receptor β (ERβ) plays critical roles in thyroid cancer progression. However, its role in thyroid cancer stem cell maintenance remains elusive. Here, we report that ERβ is overexpressed in papillary thyroid cancer stem cells (PTCSCs), whereas ablation of ERβ decreases stemness-related factors expression, diminishes ALDH⁺ cell populations, and suppresses sphere formation ability and tumor growth. Screening estrogen-responsive lncRNAs in PTC spheroid cells, we find that lncRNA-H19 is highly expressed in PTCSCs and PTC tissue specimens, which is correlated with poor overall survival. Mechanistically, estradiol (E2) significantly promotes H19 transcription via ERβ and elevates H19 expression. Silencing of H19 inhibits E2-induced sphere formation ability. Furthermore, H19 acting as a competitive endogenous RNA sequesters miRNA-3126-5p to reciprocally release ERβ expression. ERβ depletion reverses H19-induced stem-like properties upon E2 treatment. Appropriately, ERβ is upregulated in PTC tissue specimens. Notably, aspirin attenuates E2-induced cancer stem-like traits through decreasing both H19 and ERβ expression. Collectively, our findings reveal that ERβ-H19 positive feedback loop has a compelling role in PTCSC maintenance under E2 treatment and provides a potential therapeutic targeting strategy for PTC.

Long noncoding RNA ROR as a novel biomarker for progress and prognosis outcome in human cancer: a meta-analysis in the Asian population

Background

Long intergenic non-protein coding RNA, a regulator of reprogramming (ROR), has been found to play an oncogene role in various human malignant tumors. This meta-analysis aimed to synthesize available data to verify the association between clinical prognosis value and ROR expression level.

Materials and methods

We performed a systematic search by using PubMed (Medline), Embase, Cochrane Library, ScienceDirect, Springer, and ISI Web of Knowledge from inception to November 15, 2017. Eleven studies with 903 patients were included in this meta-analysis according to the exclusion and inclusion criteria, and the quality of the publications was assessed by using the Newcastle-Ottawa Scale. Pooled odds ratios (OR) and hazard ratios (HR) with 95% CI were used to describe the effect.

Results

The results showed that overexpression of ROR is positively associated with lymph node metastasis (OR=4.472, 95% CI: 3.212–6.225, Z=8.87, P=0.000), tumor invasion depth (OR=9.93, 95% CI: 5.33–18.47, Z=7.24, P<0.001), TNM stage (III/IV vs I/II, OR=2.96, 95% CI: 2.18–4.02, Z=6.95, P<0.001), distant metastasis (OR=3.142, 95% CI: 2.187–4.513, Z=6.20, P<0.001) respectively. Additionally, high expression of ROR was significantly correlated with unfavorable disease-free survival (DFS) (HR=2.74, 95% CI: 1.65–3.82, Z=4.93, P=0.000) and overall survival (OS) (HR=2.09, 95% CI: 1.64–2.54, Z=9.07, P<0.001). Subgroup analysis demonstrated that neither cancer type (digestive or respiratory system) nor sample size (more or less than 100) did not alter the prognostic value of ROR. Furthermore, we performed publication bias and sensitivity analysis in order to examine the stability of meta-analysis of ROR along with OS, which showed that the shape of the funnel plot was nearly symmetrical and the resulting pattern was not significantly influenced while disconnecting each suitable study.

Conclusion

In accordance with these results, we suggested that the overexpression of long noncoding RNA ROR could act as a novel biomarker for predicting poor prognosis in different human cancers.

Interaction of long-chain non-coding RNAs and important signaling pathways on human cancers (Review)

Long non-coding RNAs (lncRNAs) usually refer to non-coding RNA transcripts >200 nucleotides in length. In terms of the full genomic transcript, the proportion of lncRNAs far exceeds that of coding RNA. Initially, lncRNAs were considered to be the transcriptional noise of genes, but it has since been demonstrated that lncRNAs serve an important role in the regulation of cellular activities through interaction with DNA, RNA and protein. Numerous studies have demonstrated that various intricate signaling pathways are closely related to lncRNAs. Here, we focus on a large number of studies regarding the interaction of lncRNAs with important signaling pathways. It is comprehensively illustrated that lncRNAs regulate key metabolic components and regulatory factors of signaling pathways to affect the biological activities of tumor cells. Evidence suggests that the abnormal expression or mutation of lncRNAs in human tumor cells, and their interaction with signaling pathways, may provide a basis and potential target for the diagnosis and treatment of human cancers.

Long noncoding RNA ROR promotes breast cancer by regulating the TGF-β pathway

Background

Breast cancer is the leading cause of oncological mortality among women. Efficient detection of cancer cells in an early stage and potent therapeutic agents targeting metastatic tumors are highly needed to improve survival rates. Emerging evidence indicates that lncRNAs (long noncoding RNAs) are critical regulators of fundamental cellular processes in a variety of tumors including breast cancer. The functional details of these regulatory elements, however, remain largely unexplored.

Methods

In this study, lncRNA ROR (linc-ROR) was examined by real-time PCR in different breast cancer cell lines and breast tumor tissues/non-tumor tissues were collected from both breast cancer patients and healthy controls. Linc-ROR was knockdown in breast cancer cell lines and the effects on cell proliferation, migration and invasion were tested both in vitro and in vivo tumor model. Effects of linc-ROR knockdown on TGF-β signaling pathway were investigated by Western blot.

Results

Our studies have suggested that linc-ROR, a critical factor for embryonic stem cell maintenance, probably acts as an oncogenic factor in breast cancer cells, causing poor prognostic outcomes. Overexpression of linc-ROR seems to be responsible for promoting proliferation and invasion of cancer cells as well as tumor growth in nude mice. The regulatory action of linc-ROR can affect the activity of the TGF-β signaling pathway, which has been proven critical for mammary development and breast cancer.

Conclusions

The results have highlighted the potential importance of linc-ROR in the progression of advanced breast cancer, and thus will stimulate efforts in the development of novel diagnostic and therapeutic strategies.

Long noncoding RNA signature in predicting metastasis following tamoxifen treatment for ER-positive breast cancer

AIM

We aimed to develop a long noncoding RNA (lncRNA) expression signature that can predict response to tamoxifen.

MATERIALS & METHODS

LncRNA expression profiling was mined in two cohorts from Gene Expression Omnibus (GSE6532, GSE9195, n = 412).

RESULTS

A set of lncRNAs (LINC01191, RP4-639F20.1 and CTC-429P9.3) associated with distant metastasis-free survival was established. Estrogen receptor-positive breast cancer patients in the training series could be classified into high- and low-risk groups with significantly different distant metastasis-free survival values based on this signature (hazard ratio [HR]: 5.11; p = 7.28 × 10-8). The prognostic ability of this signature was confirmed in validation sets 1 (HR: 2.58; p = 1.54 × 10-2) and 2 (HR: 10.06; p = 6.85 × 10-3).

CONCLUSION

The lncRNA signature may have possible clinical implications in the selection of high-risk patients for tamoxifen therapy.

Prognostic values of the mRNA expression of natural killer receptor ligands and their association with clinicopathological features in breast cancer patients

BACKGROUND

Natural killer (NK) cells are lymphocytes of the innate immune system that have potent cytotoxic activity against tumor cells. NK cell recognition and activity towards cancer cells are regulated by an integrated interplay between numerous inhibitory and activating receptors acting in concert to eliminate tumor cells expressing cognate ligands. Despite strong evidence supporting the role of NK cells in breast cancer (BC) control, BC still develops and progresses to form large tumors and metastases. A major mechanism of BC escape from NK immunity is the alteration of the expression of NK receptor ligands. The aim of this study was to determine whether NK receptor ligands' mRNA expression might influence prognosis in BC patients and whether these effects differ by molecular subtypes and clinicopathological features.

METHODS

We used the KM plotter platform to analyze the correlation between mRNA expression of 32 NK receptor ligands and relapse-free survival (RFS) and overall survival (OS) in 3951 and 1402 BC patients, respectively. The association with tumor subtypes and clinicopathological features was determined. BC samples were split into high and low expression groups according to the best cutoff value and the two patient cohorts were compared by Kaplan-Meier survival plots. The hazard ratios with 95% confidence intervals and log rank P values were calculated and FDR-adjusted for multiple testing correction. The data was considered to be statistically significant when FDR-adjusted P value < 0.05.

RESULTS

High mRNA expression of around 80% of ligands for NK activating and inhibitory receptors associated with better RFS, which correlated with longer OS for only about half of the NK-activating ligands but for most NK-inhibitory ligands. Also, five NK-activating ligands correlated with worse prognosis. These prognostic values were differentially associated with the BC clinical criteria. In addition, the favorable prognostic influence of NK-activating ligands' upregulation, as a whole, was mainly significantly associated with HER2-positive and basal-like subtypes, lymph node positive phenotype, and high-grade tumors.

CONCLUSIONS

NK receptor ligands appear to play an important role in defining BC patient prognosis. Identification of a group of patients with worse prognosis expressing high levels of NK-activating ligands and low levels of NK-inhibitory ligands makes them ideal potential candidates for NK-based immunotherapy to eliminate residual tumor cells, prevent relapse and improve patient survival.

Crosstalk mechanisms between the WNT signaling pathway and long non-coding RNAs

The WNT/β-catenin signaling pathway controls a plethora of biological processes throughout animal development and adult life. Because of its fundamental role during animal lifespan, the WNT pathway is subject to strict positive and negative multi-layered regulation, while its aberrant activity causes a wide range of pathologies, including cancer. At present, despite the inroads into the molecules involved in WNT-mediated transcriptional responses, the fine-tuning of WNT pathway activity and the totality of its target genes have not been fully elucidated. Over the past few years, long non-coding RNAs (lncRNAs), RNA transcripts longer that 200nt that do not code for proteins, have emerged as significant transcriptional regulators. Recent studies show that lncRNAs can modulate WNT pathway outcome by affecting gene expression through diversified mechanisms, from the transcriptional to post-translational level. In this review, we selectively discuss those lncRNA-mediated mechanisms we believe the most important to WNT pathway modulation.

Functional Variants in Linc-ROR are Associated with mRNA Expression of Linc-ROR and Breast Cancer Susceptibility

Functional polymorphisms in Linc-ROR may change its ability of regulation by regulating Linc-ROR expression. However, these functional polymorphisms in Linc-ROR and their associations with breast cancer (BC) susceptibility were scarcely reported. In this molecular epidemiological study, four SNPs (rs6420545, rs4801078, rs1942348 and rs9636089) were selected in Linc-ROR by bioinformatics method. Unconditional logistic regression model was performed to analyze the associations between four SNPs and BC susceptibility adjusted for reproductive factors. Quantitative real-time (qRT) PCR was used to evaluate relative expression of Linc-ROR in plasma. The interactions of gene reproductive factors were assessed by Multifactor Dimensionality Reduction (MDR) method. A novel finding showed TT (OR: 1.79; 95%CI: 1.20-2.68) genotype of rs4801078 in Linc-ROR had a significant association with the higher risk of BC and the expression of Linc-ROR mRNA was closely related with the alleles of rs4801078. In addition, we found the interaction of rs4801078, number of pregnancy and menopausal status might increase BC risk (OR: 2.78; 95%CI: 2.74-3.61). Our results suggest that interactions of SNPs in Linc-ROR and reproductive factors might contribute to BC risk, and alleles of rs4801078 might affect Linc-ROR expression level.