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

miR-194-3p regulates epithelial-mesenchymal transition in embryonic epicardial cells via p120/β-catenin signaling

The epicardium is integral to cardiac development and facilitates endogenous heart regeneration and repair. While miR-194-3p is associated with cellular migration and invasion, its impact on epicardial cells remains uncharted. In this work we use gain-of-function and loss-of-function methodologies to investigate the function of miR-194-3p in cardiac development. We culture embryonic epicardial cells in vitro and subject them to transforming growth factor β (TGF-β) treatment to induce epithelial-mesenchymal transition (EMT) and monitor miR-194-3p expression. In addition, the effects of miR-194-3p mimics and inhibitors on epicardial cell development and changes in EMT are investigated. To validate the binding targets of miR-194-3p and its ability to recover the target gene-phenotype, we produce a mutant vector p120-catenin-3'UTR-MUT. In epicardial cells, TGF-β-induced EMT results in a notable overexpression of miR-194-3p. The administration of miR-194-3p mimics promotes EMT, which is correlated with elevated levels of mesenchymal markers. Conversely, miR-194-3p inhibitor attenuates EMT. Further investigations reveal a negative correlation between miR-194-3p and p120-catenin, which influences β-catenin level in the cell adhesion pathway. The suppression of EMT caused by the miR-194-3p inhibitor is balanced by silencing of p120-catenin. In conclusion, miR-194-3p directly targets p120-catenin and modulates its expression, which in turn alters β-catenin expression, critically influencing the EMT process in the embryonic epicardial cells via the cell adhesion mechanism.

Linc-ROR inhibits NK cell-killing activity by promoting RXRA ubiquitination and reducing MICB expression in gastric cancer patients

Linc-ROR plays an important role in gastric cancer (GC) development and progression. This study sought to determine how the aberrant expression of Linc-ROR impacts GC progression and immune evasion, and to identify new targets for GC therapy. GC cells overexpressing Linc-ROR and GSAGS cells were cocultured with NK-92 cells, respectively, and Linc-ROR expression was determined using reverse transcription polymerase chain reaction. Linc-ROR overexpression experiments were used to measure the expression of MICB, a tumor protein that is recognized by natural killer (NK) cells. Bioinformatics analysis identified retinoid X receptor α (RXRA) and YY1 as MICB-specific transcription factors. Cotransfection and ubiquitinated drug experiments found that Linc-ROR promoted the ubiquitination and degradation of RXRA. Linc-ROR was upregulated in GC tissue and high expression was associated with tumor escape from NK-92 cell-mediated immunity. Linc-ROR overexpression inhibited the expression of MICB on the cell surface by degrading RXRA. These findings indicate that Linc-ROR promotes the binding of RXRA and E3 ligase UBE4B, reducing RXRA and MICB expression, and limiting NK cell-killing activity. Linc-ROR is a critical long noncoding RNA with a tumor-promoting function in GC and thus may serve as a potential therapeutic target.

Long non-coding RNA LINC00565 regulates ADAM19 expression through sponging microRNA-532-3p, thereby facilitating clear cell renal cell carcinoma progression

Proven by publications, long non-coding RNAs (lncRNAs) play critical roles in the development of clear cell renal cell carcinoma (ccRCC). Although lncRNA LINC00565 has been implicated in the progression of various cancers, its biological effects on ccRCC remain unknown. This study aimed to investigate the biological functions of LINC00565, as well as its potential mechanism in ccRCC. Here, the expression data of mature microRNAs (miRNAs) (normal: 71, tumor: 545), messenger RNAs (mRNAs), and lncRNAs (normal: 72, tumor: 539) of ccRCC were acquired from The Cancer Genome Atlas (TCGA) database and subjected to differential expression analysis. Quantitative reverse transcriptase polymerase chain reaction analyzed the expression levels of LINC00565, miR-532-3p, and ADAM19 mRNA. TCGA database, dual-luciferase report detection, and Argonaute 2 RNA immunoprecipitation were utilized to confirm the relationships between LINC00565 and miR-532-3p and between miR-532-3p and ADAM19, respectively. The progression of ccRCC cells was determined via CCK-8, colony formation, scratch healing, and transwell assays. Western blot was applied to detect the protein levels of epithelial-mesenchymal transition markers and ADAM19. We herein suggested that LINC00565 was prominently upregulated in ccRCC tissues and cells. Knockdown of LINC00565 repressed cell progression. We further predicted and validated miR-532-3p as a target of LINC00565, and miR-532-3p could target ADAM19. Knockdown of LINC00565 resulted in ADAM19 level downregulation in ccRCC cells and suppressed miR-532-3p could restore ADAM19 level. Thus, the three RNAs constructed a ceRNA network. Overexpressed ADAM19 could eliminate the anticancer effects caused by knocking down LINC00565 on ccRCC cells. In conclusion, LINC00565 upregulated ADAM19 via absorbing miR-532-3p, thereby facilitating the progression of ccRCC cells.

Investigation of LGALS2 expression in the TCGA database reveals its clinical relevance in breast cancer immunotherapy and drug resistance

Breast cancer (BRCA) is known as the leading cause of death in women worldwide and has a poor prognosis. Traditional therapeutic strategies such as surgical resection, radiotherapy and chemotherapy can cause adverse reactions such as drug resistance. Immunotherapy, a new treatment approach with fewer side effects and stronger universality, can prolong the survival of BRCA patients and even achieve clinical cure. However, due to population heterogeneity and other reasons, there are still certain factors that limit the efficacy of immunotherapy. Therefore, the importance of finding new tumor immune biomarker cannot be emphasized enough. Studies have reported that LGALS2 was closely related to immunotherapy efficacy, however, it is unclear whether it can act as an immune checkpoint for BRCA immunotherapy. In the current study, changes in LGALS2 expression were analyzed in public datasets such as TCGA-BRCA. We found that LGALS2 expression was associated with immune infiltration, drug resistance and other characteristics of BRCA. Moreover, high LGALS2 expression was closely related to immunotherapy response, and was associated with methylation modifications and clinical resistance for the first time. These findings may help to elucidate the role of LGALS2 in BRCA for the development and clinical application of future immunotherapy strategies against BRCA.

MicroRNA-194-3p impacts autophagy and represses rotavirus replication via targeting silent information regulator 1

BACKGROUND

Rotavirus (RV) is the main cause of serious diarrhea in infants and young children worldwide. Numerous studies have demonstrated that RV use host cell mechanisms to motivate their own stabilization and multiplication by degrading, enhancing, or hijacking microRNAs (miRNAs). Therefore, exploring the molecular mechanisms by which miRNAs motivate or restrain RV replication by controlling different biological processes, including autophagy, will help to better understand the pathogenesis of RV development. This study mainly explored the effect of miR-194-3p on autophagy after RV infection and its underlying mechanism of the regulation of RV replication.

METHODS

Caco-2 cells were infected with RV and used to measure the expression levels of miR-194-3p and silent information regulator 1 (SIRT1). After transfection with plasmids and RV infection, viral structural proteins, RV titer, cell viability, and autophagy-linked proteins were tested. The degree of acetylation of p53 was further investigated. A RV-infected neonatal mouse model was constructed in vivo and was evaluated for diarrhea symptoms and lipid droplet formation.

RESULTS

The results showed that miR-194-3p was reduced but SIRT1 was elevated after RV infection. Elevation of miR-194-3p or repression of SIRT1 inhibited RV replication through the regulation of autophagy. The overexpression of SIRT1 reversed the effects of miR-194-3p on RV replication. The upregulation of miR-194-3p or the downregulation of SIRT1 repressed RV replication in vivo. MiR-194-3p targeted SIRT1 to decrease p53 acetylation.

CONCLUSION

These results were used to determine the mechanism of miR-194-3p in RV replication, and identified a novel therapeutic small RNA molecule that can be used against RV.

The Epigenetic Reader Methyl-CpG-Binding Protein 2 (MeCP2) Is an Emerging Oncogene in Cancer Biology

Epigenetic mechanisms are gene regulatory processes that control gene expression and cellular identity. Epigenetic factors include the "writers", "readers", and "erasers" of epigenetic modifications such as DNA methylation. Accordingly, the nuclear protein Methyl-CpG-Binding Protein 2 (MeCP2) is a reader of DNA methylation with key roles in cellular identity and function. Research studies have linked altered DNA methylation, deregulation of MeCP2 levels, or MECP2 gene mutations to different types of human disease. Due to the high expression level of MeCP2 in the brain, many studies have focused on its role in neurological and neurodevelopmental disorders. However, it is becoming increasingly apparent that MeCP2 also participates in the tumorigenesis of different types of human cancer, with potential oncogenic properties. It is well documented that aberrant epigenetic regulation such as altered DNA methylation may lead to cancer and the process of tumorigenesis. However, direct involvement of MeCP2 with that of human cancer was not fully investigated until lately. In recent years, a multitude of research studies from independent groups have explored the molecular mechanisms involving MeCP2 in a vast array of human cancers that focus on the oncogenic characteristics of MeCP2. Here, we provide an overview of the proposed role of MeCP2 as an emerging oncogene in different types of human cancer.

Role of MAGI2-AS3 in malignant and non-malignant disorders

MAGI2 Antisense RNA 3 (MAGI2-AS3) is a long non-coding RNA (lncRNA) transcribed from a locus on 7q21.11. This lncRNA has been described to be abnormally expressed in a variety of malignancies in correlation with many clinical characteristics. Moreover, it might participate in the pathogenesis of congenital diaphragmatic hernia, Alzheimer's disease and intervertebral disc degeneration. Mechanistically, MAGI2-AS3 can serve as a molecular sponge for miR-142-3p, miR-424-5p, miR-15b, miR-233, miR-452-5p, miR-629-5p, miR-25, miR-155, miR-23a-3p, miR-519c-3p, miR-374b-5p, miR-374a, miR-31-5p, miR-3163, miR-525-5p, miR-15-5p, miR-374a-5p, miR-374b-5p, miR-218-5p, miR-141-3p and miR-200a-3p to regulate expression of their mRNA targets. The current review summarizes the role of MAGI2-AS3 in different disorders to highlight its importance in their pathophysiology.

Loss of TTC17 promotes breast cancer metastasis through RAP1/CDC42 signaling and sensitizes it to rapamycin and paclitaxel

BACKGROUND

Breast cancer (BC) metastasis is the leading cause of poor prognosis and therapeutic failure. However, the mechanisms underlying cancer metastasis are far from clear.

METHODS

We screened candidate genes related to metastasis through genome-wide CRISPR screening and high-throughput sequencing of patients with metastatic BC, followed by a panel of metastatic model assays. The effects of tetratricopeptide repeat domain 17 (TTC17) on migration, invasion, and colony formation ability together with the responses to anticancer drugs were investigated in vitro and in vivo. The mechanism mediated by TTC17 was determined by RNA sequencing, Western blotting, immunohistochemistry, and immunofluorescence. The clinical significance of TTC17 was evaluated using BC tissue samples combined with clinicopathological data.

RESULTS

We identified the loss of TTC17 as a metastasis driver in BC, and its expression was negatively correlated with malignancy and positively correlated with patient prognosis. TTC17 loss in BC cells promoted their migration, invasion, and colony formation capacity in vitro and lung metastasis in vivo. Conversely, overexpressing TTC17 suppressed these aggressive phenotypes. Mechanistically, TTC17 knockdown in BC cells resulted in the activation of the RAP1/CDC42 pathway along with a disordered cytoskeleton in BC cells, and pharmacological blockade of CDC42 abolished the potentiation of motility and invasiveness caused by TTC17 silencing. Research on BC specimens demonstrated reduced TTC17 and increased CDC42 in metastatic tumors and lymph nodes, and low TTC17 expression was linked to more aggressive clinicopathologic characteristics. Through screening the anticancer drug library, the CDC42 inhibitor rapamycin and the microtubule-stabilizing drug paclitaxel showed stronger inhibition of TTC17-silenced BC cells, which was confirmed by more favorable efficacy in BC patients and tumor-bearing mice receiving rapamycin or paclitaxel in the TTC17^Low arm.

CONCLUSIONS

TTC17 loss is a novel factor promoting BC metastasis, that enhances migration and invasion by activating RAP1/CDC42 signaling and sensitizes BC to rapamycin and paclitaxel, which may improve stratified treatment strategies under the concept of molecular phenotyping-based precision therapy of BC.

Epi-miRNAs: Modern mediators of methylation status in human cancers

Methylation of the fundamental macromolecules, DNA/RNA, and proteins, is remarkably abundant, evolutionarily conserved, and functionally significant in cellular homeostasis and normal tissue/organism development. Disrupted methylation imprinting is strongly linked to loss of the physiological equilibrium and numerous human pathologies, and most importantly to carcinogenesis, tumor heterogeneity, and cancer progression. Mounting recent evidence has documented the active implication of miRNAs in the orchestration of the multicomponent cellular methylation machineries and the deregulation of methylation profile in the epigenetic, epitranscriptomic, and epiproteomic levels during cancer onset and progression. The elucidation of such regulatory networks between the miRNome and the cellular methylation machineries has led to the emergence of a novel subclass of miRNAs, namely "epi-miRNAs" or "epi-miRs." Herein, we have summarized the existing knowledge on the functional role of epi-miRs in the methylation dynamic landscape of human cancers and their clinical utility in modern cancer diagnostics and tailored therapeutics. This article is categorized under: RNA in Disease and Development > RNA in Disease.

A review on the importance of LINC-ROR in human disorders

Long Intergenic Non-Protein Coding RNA, Regulator Of Reprogramming (LINC-ROR) is a long non-coding RNA with diverse physiological functions. The gene encoding this transcript resides on 18q21.31. Expression levels of LINC-ROR have been reported to be dysregulated in patients with diverse disorders, including cancer, autoimmune disorders and neurodegenerative and neurodevelopmental disorders. Moreover, polymorphisms within this lncRNA have been shown to be associated with a variety of disorders, such as some kinds of cancer and some aspects of systemic lupus erythematous. Abnormal expression of LINC-ROR in some other human disorders is not yet understood. Emerging evidence suggests that LINC-ROR exerts pivotal roles in most types of human disorders as an oncogene. Differentially expressed LINC-ROR contributes in the development of diseases by changing the expression of genes that control the cell cycle. It can also exert its role by affecting the activity of some cancer-related signaling pathways and sponging tumor suppressor miRNAs. Expanding our understanding of LINC-ROR functions will pave the way for developing efficient therapeutic strategies against cancer and related disorders. The current review aims at providing a concise overview of the role of LINC-ROR in diverse human disorders through providing a summary of association studies and expression assays.

Mechanisms of Long Non-Coding RNA in Breast Cancer

The landscape of pervasive transcription in eukaryotic genomes has made space for the identification of thousands of transcripts that are difficult to frame in a specific functional category. A new class has been broadly named as long non-coding RNAs (lncRNAs) and shortly defined as transcripts that are longer than 200 nucleotides with no or limited coding potential. So far, about 19,000 lncRNAs genes have been annotated in the human genome (Gencode 41), nearly matching the number of protein-coding genes. A key scientific priority is the functional characterization of lncRNAs, a major challenge in molecular biology that has encouraged many high-throughput efforts. LncRNA studies have been stimulated by the enormous clinical potential that these molecules promise and have been based on the characterization of their expression and functional mechanisms. In this review, we illustrate some of these mechanisms as they have been pictured in the context of breast cancer.

Functional Relevance of the Long Intergenic Non-Coding RNA Regulator of Reprogramming (Linc-ROR) in Cancer Proliferation, Metastasis, and Drug Resistance

Cancer is responsible for more than 10 million deaths every year. Metastasis and drug resistance lead to a poor survival rate and are a major therapeutic challenge. Substantial evidence demonstrates that an increasing number of long non-coding RNAs are dysregulated in cancer, including the long intergenic non-coding RNA, regulator of reprogramming (linc-ROR), which mostly exerts its role as an onco-lncRNA acting as a competing endogenous RNA that sequesters micro RNAs. Although the properties of linc-ROR in relation to some cancers have been reviewed in the past, active research appends evidence constantly to a better comprehension of the role of linc-ROR in different stages of cancer. Moreover, the molecular details and some recent papers have been omitted or partially reported, thus the importance of this review aimed to contribute to the up-to-date understanding of linc-ROR and its implication in cancer tumorigenesis, progression, metastasis, and chemoresistance. As the involvement of linc-ROR in cancer is elucidated, an improvement in diagnostic and prognostic tools could promote and advance in targeted and specific therapies in precision oncology.

The upregulation of CLGN in hepatocellular carcinoma is potentially regulated by hsa-miR-194-3p and associated with patient progression

Background

Patients with hepatocellular carcinoma (HCC) have poor prognosis, especially in advanced stages. Targeted therapy is the main treatment for advanced HCC patients, but the optimal targets for HCC remain poorly understood. The main purpose of this study was to identify potential novel prognostic markers and therapeutic targets.

Methods

Firstly, differentially expressed genes (DEGs) in HCC were identified from the Gene Expression Omnibus (GEO) database. The expression, significance in prognosis, and potential mechanisms of DEGs were analyzed using GEPIA, TIMER, HPA, Kaplan Meier Plotter, CBioPortal, miRWalk, TargetScan, and ENCORI databases. Immunohistochemical staining was used to determine the protein expression levels of potential candidate genes.

Results

The mRNA levels of MND1, STXBP6, and CLGN were significantly increased in HCC (p< 0.01). HCC patients with elevated CLGN mRNA levels had poorer overall survival (OS), disease-free survival (DFS), progression-free survival (PFS), and disease-specific survival (DSS) (p < 0.05). Higher MND1 mRNA levels significantly correlated with poorer DFS in HCC patients (p< 0.05). However, there was no significant correlation between STXBP6 expression and prognosis of HCC (p> 0.05). Further analysis revealed that patients with elevated CLGN mRNA expression in advanced pathology stages had poorer prognosis (p< 0.01). In addition, CLGN protein levels were elevated in HCC compared to their levels in normal tissues. The mRNA levels of CLGN had no significant correlation with the abundance of six common tumor infiltrating lymphocytes in HCC (COR < 0.5). Moreover, the mutation rate of CLGN was less than 1% in HCC patients (10/1089). Finally, the expression level of hsa-miR-194-3p in HCC was significantly lower than that in normal tissues (p < 0.05), and prognosis of HCC with low expression of hsa-miR-194 was poor (p < 0.05).

Conclusion

The upregulation of CLGN in HCC is significantly associated with poor patient prognosis, especially in the advanced stages, and may be regulated by hsa-miR-194-3p. These findings suggest that CLGN may be closely related to the progression of HCC, and is a potential therapeutic target and prognostic indicator for patients with advanced HCC.

Functional interplay between long non-coding RNAs and Breast CSCs

Breast cancer (BC) represents aggressive cancer affecting most women’s lives globally. Metastasis and recurrence are the two most common factors in a breast cancer patient's poor prognosis. Cancer stem cells (CSCs) are tumor cells that are able to self-renew and differentiate, which is a significant factor in metastasis and recurrence of cancer. Long non-coding RNAs (lncRNAs) describe a group of RNAs that are longer than 200 nucleotides and do not have the ability to code for proteins. Some of these lncRNAs can be mainly produced in various tissues and tumor forms. In the development and spread of malignancies, lncRNAs have a significant role in influencing multiple signaling pathways positively or negatively, making them promise useful diagnostic and prognostic markers in treating the disease and guiding clinical therapy. However, it is not well known how the interaction of lncRNAs with CSCs will affect cancer development and progression.

Here, in this review, we attempt to summarize recent findings that focus on lncRNAs affect cancer stem cell self-renewal and differentiation in breast cancer development and progression, as well as the strategies and challenges for overcoming lncRNA's therapeutic resistance.

Introduction of long non-coding RNAs to regulate autophagy-associated therapy resistance in cancer

Autophagy is a lysosomal degradation pathway that depends on various evolutionarily conserved autophagy-related genes (ATGs). Dysregulation of autophagy plays an important role in the occurrence and development of cancer. Chemotherapy, targeted therapy, radiotherapy, and immunotherapy are important treatment options for cancer, which can significantly improve the survival rate of cancer patients. However, the occurrence of therapy resistance results in therapeutic failure and poor prognosis of cancer. Accumulating studies have found that long non-coding RNAs (lncRNAs) are well known as crucial regulators to control autophagy through regulating ATGs and autophagy-associated signaling pathways, including the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, ultimately mediating chemoresistance and radioresistance. Taken together, this review systematically summarizes and elucidates the pivotal role of lncRNAs in cancer chemoresistance and radioresistance via regulating autophagy. Understanding the specific mechanism of which may provide autophagy-related therapeutic targets for cancer in the future.

A robust immune-related lncRNA signature for the prognosis of human colorectal cancer

Background: Colorectal cancer (CRC) is one of the most prevalent malignant cancers worldwide. Immune-related long non-coding RNAs (IRlncRNAs) are proved to be essential in the development and progression of carcinoma. The purpose of the present study was to develop and validate a prognostic IRlncRNA signature for CRC patients.

Methods: Gene expression profiles of CRC samples were downloaded from The Cancer Genome Atlas (TCGA) database. Immune-related genes were obtained from the ImmPort database and were used to identify IRlncRNA by correlation analysis. Through LASSO Cox regression analyses, a prognostic signature was constructed. Functional enrichment analysis was performed by gene set enrichment analysis (GSEA). TIMER2.0 web server and tumor immune dysfunction and exclusion (TIDE) algorithm were employed to analyze the association between our model and tumor-infiltrating immune cells and immunotherapy response. The expression levels of IRlncRNAs in cell lines were detected by quantitative real-time PCR (qPCR).

Results: A 9-IRlncRNA signature was developed by a LASSO Cox proportional regression model. Based on the signature, CRC patients were divided into high- and low-risk groups with different prognoses. GSEA results indicated that patients in high-risk group were associated with cancer-related pathways. In addition, patients in low-risk group were found to have more infiltration of anti-tumor immune cells and might show a favorable response to immunotherapy. Finally, the result of qPCR revealed that most IRlncRNAs were differently expressed between normal and tumor cell lines.

Conclusion: The constructed 9-IRlncRNA signature has potential to predict the prognosis of CRC patients and may be helpful to guide personalized immunotherapy.

LINC-DUBR Suppresses Malignant Progression of Ovarian Cancer by Downregulating miR-107 to Induce SMAC Expression

Background

LINC-DUBR may be a potential therapeutic target in ovarian cancer (OC). The purpose of this research was to explore the impact of miR-107 on the tumorigenicity of OC and its underlying molecular mechanisms.

Methods

RT-qPCR was adopted to measure the expression of LINC-DUBR and miR-107 in ovarian cancer tissues and cells. CCK-8 assays and transwell chamber assays were conducted to evaluate the impacts of LINC-DUBR and miR-107 on the proliferation and invasion of human ovarian cancer cells (SKOV3). In addition, we determined the relationship between LINC-DUBR, miR-107, and SMAC using TargetScan and luciferase reporter assay. The protein expression of SMAC was determined by western blot.

Results

Compared with normal tissues and cells, LINC-DUBR was downregulated and miR-107 was highly expressed in ovarian cancer tissues and cell lines. Overexpression of LINC-DUBR inhibited the cell proliferation and invasive ability in OC cells SKOV3. The luciferase reporter assay proved overexpression of LINC-DUBR repressed cells proliferation and invasion via binding to miR-107 in ovarian cancer. In addition, we found that SMAC was downregulated directly by miR-107 in ovarian cancer. miR-107 mimic significantly increased cell proliferation and invasiveness of SKOV3, while overexpressed SMAC eliminated this effect. Furthermore, miR-107 could regulate the XIAP/caspase-3 signaling pathway in ovarian cancer by targeting SMAC.

Conclusion

LINC-DUBR suppressed malignant progression of ovarian cancer by downregulating miR-107 to induce SMAC expression and involving in the XIAP/caspase-3 signaling pathway.

Linc-ROR facilitates progression and angiogenesis of hepatocellular carcinoma by modulating DEPDC1 expression

Linc-ROR have been well-demonstrated to play important roles in cancer progression and angiogenesis. However, the underlying oncogenic mechanism of Linc-ROR in hepatocellular carcinoma is poorly understood. In this study, we demonstrate that Linc-ROR plays an oncogenic role in part through its positive regulation of DEPDC1 expression. Mechanistically, Linc-ROR acts as competing endogenous RNA to stabilize DEPDC1 mRNA and regulates DEPDC1 mRNA stability by binding HNRNPK. Thus, these findings suggest that function of Linc-ROR-mediated DEPDC1 could predispose hepatocellular carcinoma patients to progression and angiogenesis, and may serve as a potential target for anticancer therapies.

lncRNA and breast cancer: Progress from identifying mechanisms to challenges and opportunities of clinical treatment

Breast cancer is a malignant tumor that has a high mortality rate and mostly occurs in women. Although significant progress has been made in the implementation of personalized treatment strategies for molecular subtypes in breast cancer, the therapeutic response is often not satisfactory. Studies have reported that long non-coding RNAs (lncRNAs) are abnormally expressed in breast cancer and closely related to the occurrence and development of breast cancer. In addition, the high tissue and cell-type specificity makes lncRNAs particularly attractive as diagnostic biomarkers, prognostic factors, and specific therapeutic targets. Therefore, an in-depth understanding of the regulatory mechanisms of lncRNAs in breast cancer is essential for developing new treatment strategies. In this review, we systematically elucidate the general characteristics, potential mechanisms, and targeted therapy of lncRNAs and discuss the emerging functions of lncRNAs in breast cancer. Additionally, we also highlight the advantages and challenges of using lncRNAs as biomarkers for diagnosis or therapeutic targets for drug resistance in breast cancer and present future perspectives in clinical practice.

Long Non-Coding RNAs as Potential Diagnostic and Prognostic Biomarkers in Breast Cancer: Progress and Prospects

Breast cancer is the most common malignancy among women worldwide, excluding non-melanoma skin cancer. It is now well understood that breast cancer is a heterogeneous entity that exhibits distinctive histological and biological features, treatment responses and prognostic patterns. Therefore, the identification of novel ideal diagnostic and prognostic biomarkers is of utmost importance. Long non-coding RNAs (lncRNAs) are commonly defined as transcripts longer than 200 nucleotides that lack coding potential. Extensive research has shown that lncRNAs are involved in multiple human cancers, including breast cancer. LncRNAs with dysregulated expression can act as oncogenes or tumor-suppressor genes to regulate malignant transformation processes, such as proliferation, invasion, migration and drug resistance. Intriguingly, the expression profiles of lncRNAs tend to be highly cell-type-specific, tissue-specific, disease-specific or developmental stage-specific, which makes them suitable biomarkers for breast cancer diagnosis and prognosis.

Establishing a three-miRNA signature as a prognostic model for colorectal cancer through bioinformatics analysis

Background: Identification of more promising microRNAs (miRNAs) are being extensively studied with respect to colorectal cancer (CRC), since CRC is the leading cause of cancer deaths and most common malignant tumors worldwide. A series of colon cancer (CCa) samples from The Cancer Genome Atlas (TCGA) were analyzed to provide a new perspective into this field.

Methods: The expression of miRNAs, mRNAs and the clinical data of 437 CRC patients were downloaded from the TCGA database. The survival-related differentially expressed miRNAs (sDMIRs) and mRNAs were detected by COX regression analysis. The high-risk group and low-risk group were separated by the median risk score of the risk score model. The potential clinical characteristics of these sDMIRs were analyzed by R software. The potential molecular mechanisms of these sDMIRs were explored by computational biology. The expression levels of three sDMIRs were explored by qPCR in CRC samples.

Results: Three DMIRs (hsa-miR-21-3p, hsa-miR-194-3p and hsa-miR-891a-5p) correlated with the most remarkable prognostic values of CRC patients were selected to establish the risk score model (RSM) by univariate and multivariate COX regression analysis and the survival probability of the low-risk group was longer than that in the high-risk group. We detected the target genes of three sDMIRs and the potential molecular mechanisms of these sDMIRs. We further verified the high expression levels of hsa-miR-21-3p and hsa-miR-194-3p were associated with the early T-stages, while hsa-miR-891a-5p illustrated the reversed result.

Conclusion: Our study demonstrated three sDMIRs with significantly clinical values illustrated the potential predicting values in the prognosis of CRC patients. Our results may provide a new perspective for the diagnostic methods and treatment strategies in CRC patients.

CircUBAP2 Promotes MMP9-Mediated Oncogenic Effect via Sponging miR-194-3p in Hepatocellular Carcinoma

BACKGROUND

The physiological regulatory functions of circRNAs have become a topic of intensive research in recent years. Increasing evidence supports a significant role of circRNAs during cancer initiation and progression, including hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

A bioinformatics analysis from three independent Gene Expression Omnibus (GEO) databases was performed to profile and screen the dysregulated circRNAs in HCC. RT-qPCR was used to examine the expression level of circUBAP2 in HCC and adjacent non-tumor tissues. Then, proliferation assays (CCK8 and colony formation) and migration assays (transwell and wound healing) were performed to examine effect of circUBAP2 in vitro. Immunoprecipitation, RNA pulldown, FISH, and dual-luciferase reporter assay was conducted to explore the circUBAP2-related mechanism for regulating HCC progression. Moreover, a mouse xenograft model and a mouse lung metastasis model confirmed the effect of circUBAP2 in vivo.

RESULTS

In this study, we found a novel circRNA: circUBAP2, which was identified by bioinformatics analysis. Among 91 HCC patients, circUBAP2 was significantly upregulated in HCC tissues, and negatively correlated with aggressive clinical characteristics and prognosis. Functional assays demonstrated that circUBAP2 promoted cell proliferation, colony formation, migration, and invasion in vitro. Moreover, circUBAP2 enhanced tumor growth and pulmonary metastasis in vivo. Mechanistically, circUBAP2 acts as a competing endogenous RNA (ceRNA) for miR-194-3p, a tumor suppressor in HCC. We confirmed that MMP9 was direct target for miR-194-3p, which was regulated by circUBAP2.

CONCLUSION

CircUBAP2 plays a significant role in promoting HCC via the miR-194-3p/MMP9 pathway and could serve as a promising prognostic biomarker and novel therapeutic target for HCC patients.

Non-coding RNA in cancer

Majority of the human genome is transcribed to RNAs that do not encode proteins. These non-coding RNAs (ncRNAs) play crucial roles in regulating the initiation and progression of various cancers. Given the importance of the ncRNAs, the roles of ncRNAs in cancers have been reviewed elsewhere. Thus, in this review, we mainly focus on the recent studies of the function, regulatory mechanism and therapeutic potential of the ncRNAs including microRNA (miRNA), long ncRNA (lncRNA), circular RNA (circRNA) and PIWI interacting RNA (piRNA), in different type of cancers.

LncRNA-miRNA axes in breast cancer: Novel points of interaction for strategic attack

Therapeutic effectiveness in breast cancer can be limited by the underlying mechanisms of pathogenesis, including epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs) and drug resistance. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are master regulators of gene expression and are functionally important mediators in these mechanisms of pathogenesis. Intricate crosstalks between these non-coding RNAs form complex regulatory networks of post-transcriptional gene regulation. Depending on the specific lncRNA/miRNA interaction, the lncRNA-miRNA axis can have tumor suppressor or oncogenic effects, thus defining the lncRNA-miRNA axis is important for determining targetability. Herein, we summarize the current literature describing lncRNA-miRNA interactions that are critical in the molecular mechanisms that regulate EMT, CSCs and drug resistance in breast cancer. Further, we review both the well-studied and potential novel mechanisms of lncRNA-miRNA interactions in breast cancer.

LINC00518 Promotes Cell Proliferation by Regulating the Cell Cycle of Lung Adenocarcinoma Through miR-185-3p Targeting MECP2

Previous studies have shown that long intergenic non-protein coding RNA 00518 (LINC00518) are essential for the cell growth and metastasis of human cancer. However, the role of LINC00518 in lung adenocarcinoma (LUAD) is still unknown. This research put emphasis on the function of LINC00518 on the cell growth of LUAD. The lncRNA, miRNA and mRNA expression were measured by using qRT-PCR. Protein levels were measured by using Western blotting. CCK-8, colony formation assays and transwell assay were performed to evaluate the cell proliferation ability and invasion. Bioinformatic analysis and luciferase reporter assays were chosen to confirm the mechanism of LINC00518 in LUAD. We found that LINC00518 was highly expressed in LUAD specimens and the high-expression was negatively correlated with the overall survival rates. This finding was also proved in the LUAD cell lines. Through a series of in vitro and in vivo experiments, we proved that LICN00518 promoted the cell growth of LUAD by regulating the cell cycle. Moreover, LICN00518 upregulated the expression of MECP2 by mutagenesis of miR-185-3p. The results suggested that LICN00518 could be used as a survival indicator and potential therapeutic target for LUAD patients.

STAT3-induced HLA-F-AS1 promotes cell proliferation and stemness characteristics in triple negative breast cancer cells by upregulating TRABD

Breast cancer (BC) is one of the most common malignances and is a leading cause of cancer-related deaths in women globally. Triple negative breast cancer (TNBC) is a common subtype of BC. Emerging evidence has indicated the crucial roles of long noncoding RNAs (lncRNAs) in the tumorigenesis of TNBC. Our aim was to explore the role and regulatory mechanism of lncRNA HLA-F antisense RNA 1 (HLA-F-AS1) in TNBC cells. Cell counting kit-8 (CCK-8) assay, colony formation assay, flow cytometry analysis and western blot analysis were used to measure HLA-F-AS1-mediated cellular behaviors in TNBC. Xenograft tumor assay was applied to assess biological function of HLA-F-AS1 in vivo. Luciferase reporter assay and RNA pull down assay were used to verify the binding ability between molecules. Our findings demonstrated that HLA-F-AS1 expression was significantly upregulated in TNBC tissues and cells, and high level of HLA-F-AS1 indicated the poor prognosis of patients with TNBC. HLA-F-AS1 promoted TNBC progression by facilitating cell proliferation and stemness maintenance and inhibiting cell cycle arrest at G0/G1 stage and apoptosis in vitro as well as inducing tumor growth in vivo. HLA-F-AS1. In addition, signal transducer and activator of transcription 3 (STAT3) transcriptionally induced HLA-F-AS1 upregulation in TNBC cells via interacting with HLA-F-AS1 promoter. Moreover, HLA-F-AS1 acted as the molecular sponge of microRNA 541-3p (miR-541-3p) to elevate TRABD (TraB domain containing) expression in TNBC cells. Rescue experiments confirmed that the decrease of cell proliferation and stemness characteristics under silenced HLA-F-AS1 was rescued by TRABD overexpression in TNBC cells. In conclusion, STAT3-induced HLA-F-AS1 facilitates cell proliferation and stemness characteristics in TNBC by miR-541-3p-dependent upregulation of TRABD, which might provide a potential novel direction for the treatment of TNBC.

Identification of chemoresistance-associated microRNAs and hub genes in breast cancer using bioinformatics analysis

Breast cancer threatens women's health. Although there are a lot of methods to treat breast cancer, chemotherapy resistance still hinders the effectiveness of treatment. This study attempts to explore the mechanism of chemotherapy resistance from the perspective of miRNA and look for several new targets for developing new drugs. Three datasets (GSE73736, GSE71142 and GSE6434) from Gene Expression Omnibus (GEO) were used for the bioinformatics analysis. Differentially expressed miRNAs (DE-miRNAs) and differentially expressed genes (DE-genes) were obtained by using R package "limma". DAVID tool was used to perform gene ontology annotation analysis (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis for the overlapping genes. Protein-protein interaction (PPI) network was established by STRING database and visualized by software Cytoscape. Hub genes were identified by software Cytoscape. The prognostic value of hub genes was assessed through Kaplan-Meier plotter website. In total, 22 DE-miRNAs, 1932 DE-genes and top 10 hub genes were obtained. The genes were mainly enriched in cell signaling pathways like ErbB signaling pathway and PI3K / AKT/mTOR pathway. These pathways have a significant impact on the proliferation, invasion and drug resistance in cancer. MiRNA-Gene interaction may provide new insight for exploring the mechanism of chemotherapy resistance in breast cancer. Our study ultimately identified effective biomarkers and potential drug targets, which may enhance the effect of chemotherapy in patients with breast cancer.

A Novel Long Non-Coding RNA lnc030 Maintains Breast Cancer Stem Cell Stemness by Stabilizing SQLE mRNA and Increasing Cholesterol Synthesis

Cancer stem cells (CSCs) are considered the roots of cancer metastasis and recurrence (CSCs), due in part to their self-renewal and therapy resistance properties. However, the underlying mechanisms for the regulation of CSC stemness are poorly understood. Recently, increasing evidence shows that long non-coding RNAs (lncRNAs) are critical regulators for cancer cell function in various malignancies including breast cancer, but how lncRNAs regulate the function of breast cancer stem cells (BCSCs) remains to be determined. Herein, using lncRNA/mRNA microarray assays, a novel lncRNA (named lnc030) is identified, which is highly expressed in BCSCs in vitro and in vivo, as a pivotal regulator in maintaining BCSC stemness and promoting tumorigenesis. Mechanistically, lnc030 cooperates with poly(rC) binding protein 2(PCBP2) to stabilize squalene epoxidase (SQLE) mRNA, resulting in an increase of cholesterol synthesis. The increased cholesterol in turn actives PI3K/Akt signaling, which governs BCSC stemness. In summary, these findings demonstrate that a new, lnc030-based mechanism for regulating cholesterol synthesis and stemness properties of BCSCs. The lnc030-SQLE-cholesterol synthesis pathway may serve as an effective therapeutic target for BCSC elimination and breast cancer treatment.

LncRNA SPINT1-AS1 promotes breast cancer proliferation and metastasis by sponging let-7 a/b/i-5p

BACKGROUND

A growing number of studies have shown that long non-coding RNAs (lncRNAs) play an important role in the occurrence and development of tumors. In this study, we explored the function and molecular mechanism of lncRNA SPINT1-AS1 in breast cancer progression.

METHODS

A total of 30 patients and 25 healthy controls were enrolled to detect the expression of SPINT1-AS1 in the serum by RT-qPCR. CCK-8 assay, clone formation assay, EdU assay, Transwell assay, Flow cytometry for apoptosis assay and wound healing assays were used to explore the effects of SPINT1-AS1 on the proliferation and migration of breast cancer cells. Bioinformatics analysis were used to enrich the downstream target genes and related pathways of miRNAs interacting with SPINT1-AS1, construct a competitive endogenous RNA (ceRNA) network diagram.

RESULTS

SPINT1-AS1 is up-regulated in the serum of breast cancer patients and breast cancer cell lines. The proliferation and migration ability of breast cancer cells were decreased significantly after SPINT1-AS1 knockdown, and it may inhibit its expression by sponging miR-let-7a/b/i-5p, thereby promoting breast cancer progression.

CONCLUSIONS

SPINT1-AS1 can promote the proliferation and migration of breast cancer cells by regulating miR-let-7a/b/i-5p, suggesting that it may be an important regulator of breast cancer progression.

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.