LncRNAs in breast cancer: a link to future approaches

Long non-coding RNAs and their role in breast cancer pathogenesis and drug resistance: Navigating the non-coding landscape review

Despite the progress made in the development of targeted therapies, breast cancer (BC) continues to pose a significant threat to the health of women. Transcriptomics has emerged due to the advancements in high-throughput sequencing technology. This provides crucial information about the role of non-coding RNAs (ncRNAs) in human cells, particularly long ncRNAs (lncRNAs), in disease development and function. When the control of these ncRNAs is disrupted, various illnesses emerge, including cancer. Numerous studies have produced empirical data on the function of lncRNAs in tumorigenesis and disease development. However, the roles and mechanisms of numerous lncRNAs remain unidentified at the molecular level because their regulatory role and the functional implications of abnormalities in cancer biology have yet to be thoroughly defined. The review gives an itemized summary of the most current developments in the role of lncRNA in BC, focusing on three main pathways, PI3K, MAPK, NF-kB, and hypoxia, and their resistance mechanisms.

A Comprehensive Bioinformatic Analysis Identifies a Tumor Suppressor Landscape of the MEG3 lncRNA in Breast Cancer

Breast cancer (BC) is the leading cause of cancer mortality in women and a major risk to world health. Therefore, effective strategies are required for prompt diagnosis and treatment. Nowadays, non-coding RNAs (ncRNAs), particularly long ncRNAs (lncRNAs), have assumed a significant role in the prognosis and diagnosis of diseases, including cancer. In the present study, surveying the bioinformatic tools, including the lncRNADisease v2.0, OncoDB, InteractiVenn, GEPIA, RAID, COXPRESdb, DAVID v6.8, GEO2R, and LncSEA, we proposed the Maternally Expressed Gene (MEG3) as a potential biomarker in BC. This lncRNA significantly downregulates in BC and is associated with tumor size, metastasis, and pathological stage. MEG3 expression is downregulated in several types of primary human cancers and tumor cell lines, which raises the possibility that it could act as a tumor suppressor. The results suggest that MEG3 may play a crucial role in fundamental pathways, including apoptosis, and interact with essential genes and proteins such as P53. It may also be associated with the prognosis, proliferation, migration, invasion, and metastasis of BC.

The Role of lncRNAs in the Protective Action of Tamoxifen on the Ovaries of Tumor-Bearing Rats Receiving Cyclophosphamide

Infertility due to ovarian toxicity is a common side effect of cancer treatment in premenopausal women. Tamoxifen (TAM) is a selective estrogen receptor modulator that prevented radiation- and chemotherapy-induced ovarian failure in preclinical studies. In the current study, we examined the potential regulatory role of long noncoding RNAs (lncRNAs) in the mechanism of action of TAM in the ovaries of tumor-bearing rats receiving cyclophosphamide (CPA) as cancer therapy. We identified 166 lncRNAs, among which 49 were demonstrated to be differentially expressed (DELs) in the ovaries of rats receiving TAM and CPA compared to those receiving only CPA. A total of 24 DELs were upregulated and 25 downregulated by tamoxifen. The identified DELs shared the characteristics of noncoding RNAs described in other reproductive tissues. Eleven of the identified DELs displayed divergent modes of action, regulating target transcripts via both cis- and trans-acting pathways. Functional enrichment analysis revealed that, among target genes ascribed to the identified DELs, the majority were involved in apoptosis, cell adhesion, immune response, and ovarian aging. The presented data suggest that the molecular mechanisms behind tamoxifen's protective effects in the ovaries may involve lncRNA-dependent regulation of critical signaling pathways related to inhibition of follicular transition and ovarian aging, along with the suppression of apoptosis and regulation of cell adhesion. Employing a tumor-bearing animal model undergoing chemotherapy, which accurately reflects the conditions of mammary cancer, reinforces the obtained results. Given that tamoxifen remains a key player in the management and prevention of breast cancer, understanding its ovarian-specific actions in cancer patients is crucial and requires detailed functional studies to clarify the underlying molecular mechanisms.

The Tumour Microenvironment and Epigenetic Regulation in BRCA1 Pathogenic Variant-Associated Breast Cancers

Background/Objectives: BRCA1 pathogenic variant (PV)-associated breast cancers are most commonly seen in hereditary genetic conditions such as the autosomal-dominant Hereditary Breast and Ovarian Cancer (HBOC) syndrome, and rarely in sporadic breast cancer. Such breast cancers tend to exhibit greater aggressiveness and poorer prognoses due to the influence of BRCA1 pathogenic variants (PVs) on the tumour microenvironment. Additionally, while the genetic basis of BRCA1 PV breast cancer is well-studied, the role of epigenetic mediators in the tumourigenesis of these hereditary breast cancers is also worth exploring. Results: PVs in the BRCA1 gene interact with stromal cells and immune cells, promoting epithelial-mesenchymal transition, angiogenesis, and affecting oestrogen levels. Additionally, BRCA1 PVs contribute to breast cancer development through epigenetic effects on cells, including DNA methylation and histone acetylation, leading to the suppression of proto-oncogenes and dysregulation of cytokines. In terms of epigenetics, lysine-specific demethylase 1 (LSD-1) is considered a master epigenetic regulator, governing both transcriptional repression and activation. It exerts epigenetic control over BRCA1 and, to a lesser extent, BRCA2 genes. The upregulation of LSD-1 is generally associated with a poorer prognosis in cancer patients. In the context of breast cancer in BRCA1/2 PV carriers, LSD-1 contributes to tumour development through various mechanisms. These include the maintenance of a hypoxic environment and direct suppression of BRCA1 gene expression. Conclusions: While LSD-1 itself does not directly cause mutations in BRCA1 or BRCA2 genes, its epigenetic influence sheds light on the potential role of LSD-1 inhibitors as a therapeutic approach in managing breast cancer, particularly in individuals with BRCA1/2 PVs. Targeting LSD-1 may help counteract its detrimental effects and provide a promising avenue for therapy in this specific subgroup of breast cancer.

LUCAT1-Mediated Competing Endogenous RNA (ceRNA) Network in Triple-Negative Breast Cancer

Breast cancer is a heterogeneous disease comprising multiple molecularly distinct subtypes with varied prevalence, prognostics, and treatment strategies. Among them, triple-negative breast cancer, though the least prevalent, is the most aggressive subtype, with limited therapeutic options. Recent emergence of competing endogenous RNA (ceRNA) networks has highlighted how long noncoding RNAs (lncRNAs), microRNAs (miRs), and mRNA orchestrate a complex interplay meticulously modulating mRNA functionality. Focusing on TNBC, this study aimed to construct a ceRNA network using differentially expressed lncRNAs, miRs, and mRNAs. We queried the differentially expressed lncRNAs (DElncRNAs) between TNBC and luminal samples and found 389 upregulated and 386 downregulated lncRNAs, including novel transcripts in TNBC. DElncRNAs were further evaluated for their clinical, functional, and mechanistic relevance to TNBCs using the lnc2cancer 3.0 database, which presented LUCAT1 (lung cancer-associated transcript 1) as a putative node. Next, the ceRNA network (lncRNA-miRNA-mRNA) of LUCAT1 was established. Several miRNA-mRNA connections of LUCAT1 implicated in regulating stemness (LUCAT1-miR-375-Yap1, LUCAT1-miR181-5p-Wnt, LUCAT1-miR-199a-5p-ZEB1), apoptosis (LUCAT1-miR-181c-5p-Bcl2), drug efflux (LUCAT1-miR-200c-ABCB1, LRP1, MRP5, MDR1), and sheddase activities (LUCAT1-miR-493-5p-ADAM10) were identified, indicating an intricate regulatory mechanism of LUCAT1 in TNBC. Indeed, LUCAT1 silencing led to mitigated cell growth, migration, and stem-like features in TNBC. This work sheds light on the LUCAT1 ceRNA network in TNBC and implies its involvement in TNBC growth and progression.

Therapeutic Potential of lncRNAs in Regulating Disulfidptosis for Cancer Treatment

Non-coding RNAs (lncRNAs) play critical roles in various cellular processes, including a novel form of regulated cell death known as disulfidptosis, characterized by accumulating protein disulfide bonds and severe endoplasmic reticulum stress. This review highlights the therapeutic potential of lncRNAs in regulating disulfidptosis for cancer treatment, emphasizing their influence on key pathway components such as GPX4, SLC7A11, and PDIA family members. Recent studies have demonstrated that targeting specific lncRNAs can sensitize cancer cells to disulfidptosis, offering a promising approach to cancer therapy. The regulation of disulfidptosis by lncRNAs involves various signaling pathways, including oxidative stress, ER stress, and calcium signaling. This review also discusses the molecular mechanisms underlying lncRNA regulation of disulfidptosis, the challenges of developing lncRNA-based therapies, and the future potential of this rapidly advancing field in cancer research.

Expression of HOTAIR and PTGS2 as potential biomarkers in chronic myeloid leukemia patients in Brazil

Chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasm in which all the patients has the translocation (9;22) that generates de BCR::ABL1 tyrosine kinase. Despite this disease possessing a good biomarker (BCR::ABL1 transcripts level) for diagnosis and prognosis, many studies has been performed to investigate other molecules, such as the long noncoding RNAs (lncRNAs) and mRNAs, as potential biomarkers with the aim of predicting a change in BCR::ABL1 levels and as an associated biomarker. A RNAseq was performed comparing 6 CML patients with high BCR::ABL1 expression with 6 healthy control individuals, comprising the investigation cohort to investigate these molecules. To validate the results obtained by RNAseq, samples of 87 CML patients and 42 healthy controls were used in the validation cohort by RT-qPCR assays. The results showed lower expression of HOTAIR and PTGS2 in CML patients. The HOTAIR expression is inversely associated with BCR::ABL1 expression in imatinib-treated CML patients, and to PTGS2 showing that CML patients with high BCR::ABL1 expression showed reduced PTGS2 expression.

Longitudinal multiomics analysis of aggressive pituitary neuroendocrine tumors: comparing primary and recurrent tumors from the same patient, reveals genomic stability and heterogeneous transcriptomic profiles with alterations in metabolic pathways

Pituitary neuroendocrine tumors (PitNET) represent the vast majority of sellar masses. Some behave aggressively, growing rapidly and invading surrounding tissues, with high rates of recurrence and resistance to therapy. Our aim was to establish patterns of genomic, transcriptomic and methylomic evolution throughout time in primary and recurrent tumors from the same patient. Therefore, we performed transcriptome- and exome-sequencing and methylome microarrays of aggressive, primary, and recurrent PitNET from the same patient. Primary and recurrent tumors showed a similar exome profile, potentially indicating a stable genome over time. In contrast, the transcriptome of primary and recurrent PitNET was dissimilar. Gonadotroph, silent corticotroph, as well as metastatic corticotroph and a somatotroph PitNET expressed genes related to fatty acid biosynthesis and metabolism, phosphatidylinositol signaling, glycerophospholipid and phospholipase D signaling, respectively. Diacylglycerol kinase gamma (DGKG), a key enzyme in glycerophospholipid metabolism and phosphatidylinositol signaling pathways, was differentially expressed between primary and recurrent PitNET. These alterations did not seem to be regulated by DNA methylation, but rather by several transcription factors. Molecular docking showed that dasatinib, a small molecule tyrosine kinase inhibitor used in the treatment of chronic lymphocytic and acute lymphoblastic leukemia, could target DGKG. Dasatinib induced apoptosis and decreased proliferation in GH3 cells. Our data indicate that pituitary tumorigenesis could be driven by transcriptomically heterogeneous clones, and we describe alternative pharmacological therapies for aggressive and recurrent PitNET.

The emerging roles of LINC00511 in breast cancer development and therapy

Breast cancer (BC) is associated with malignant tumors in women worldwide with persistently high incidence and mortality rates. The traditional therapies including surgery, chemotherapy, radiotherapy and targeted therapy have certain therapeutic effects on BC patients, but acquired drug resistance can lead to tumor recurrence and metastasis. This remains a clinical challenge that is difficult to solve during treatment. Therefore, continued research is needed to identify effective targets and treatment methods, to ultimately implement personalized treatment strategies. Several studies have implicated that the long non-coding RNA LINC00511 is closely linked to the occurrence, development and drug resistance of BC. Here we will review the structure and the mechanisms of action of lnc RNA LINC00511 in various cancers, and then explore its expression and its related regulatory mechanisms during BC. In addition, we will discuss the biological functions and the potential clinical applications of LINC00511 in BC.

LncRNA OIP5-AS1 Upregulates the Cyclin D2 Levels to Promote Metastasis of Breast Cancer by Targeting miR-150-5p

OBJECTIVE

Breast cancer (BC) is a cancer that seriously affects women's health. BC cell migration increases the mortality of BC patients. Current studies have shown that long noncoding RNAs (LncRNAs) are related to the metastasis mechanism of BC. This study aimed to explore the function and role of LncRNA OIP5-AS1 in BC. And we analyzed its regulatory mechanism and related modification process.

METHODS

Our study analyzed the expression pattern of OIP5-AS1 in BC tissues and cell lines by qRT-PCR. The effects of OIP5-AS1 on the function of BC cells were detected by CCK-8 and transwell experiments. Bioinformatics analysis and double luciferase reporter gene detection were used to confirm the correlation between OIP5-AS1 and miR-150-5p and between miR-150-5p and Cyclin D2 (CCND2). The rescue test analyzed the effect of miR-150-5p regulating OIP5-AS1. In addition, the N6-methyladenosine (m6A) modification process of OIP5-AS1 was analyzed by RNA m6A dot blot, RIP assay, and double luciferase report experiment.

RESULTS

OIP5-AS1 was significantly upregulated in BC tissues and cell lines. OIP5-AS1 knockdown inhibited BC cell viability, migration and invasion. OIP5-AS1 upregulated CCND2 by binding with miR-150-5p. This process affected the metastasis of BC. Higher degree of m6A methylation was confirmed in BC cell lines. There were some binding sites between methyltransferase like 3 (METTL3) and OIP5-AS1. Moreover, the silencing of METTL3 inhibited the OIP5-AS1 expression through decreasing the m6A methylation levels.

CONCLUSIONS

LncRNA OIP5-AS1 promoted cell viability and metastasis of BC cells by targeting miR-150-5p/CCND2 axis. This process was modified by m6A methylation of METTL3.

LINC01806 Promotes Breast Cancer Growth and Metastasis via Sponging miR-1286 to Disinhibit ZEB1 Expression

Breast cancer (BC) is the most abundant and aggressive cancer that impacts millions of women with poorly understood mechanisms. Here, we aimed to investigate the function of LINC01806 in BC development. Human BC tissues and nearby normal specimens were taken from diagnosed BC patients. The expression levels of LINC01806, miR-1286, ZEB1, and EMT-related markers were evaluated by qRT-PCR and western blotting. FISH was used to visualize the subcellular localization of LINC01806. The viability, proliferation, migration and invasion capacities of BC cells were assessed by MTT, colony formation, and transwell assays. Interactions among LINC01806, miR-1286 and ZEB1 were validated by dual luciferase assay. The unpaired Student t-test (for two groups) or one-way ANOVA following with Tukey post-hoc test (for more than three groups) was employed for statistical analysis. LINC01806 level was elevated in BC tissues. Knockdown of LINC01806 suppressed EMT process and BC cell proliferation, migration, and invasion. LINC01806 co-localized and directly bound with miR-1286 in the cytoplasm. MiR-1286 inhibitor blocked the effects of LINC01806 knockdown on BC cell EMT, proliferation and migration. MiR-1286 targeted ZEB1 and overexpression of ZEB1 blocked the regulatory functions of miR-1286 mimics in BC. LINC01806 facilitates EMT and accelerates BC cell proliferation, migration, and invasion via acting as miR-1286 sponge to disinhibit ZEB1 expression.

LPI-SKMSC: Predicting LncRNA-Protein Interactions with Segmented k-mer Frequencies and Multi-space Clustering

 Long noncoding RNAs (lncRNAs) have significant regulatory roles in gene expression. Interactions with proteins are one of the ways lncRNAs play their roles. Since experiments to determine lncRNA-protein interactions (LPIs) are expensive and time-consuming, many computational methods for predicting LPIs have been proposed as alternatives. In the LPIs prediction problem, there commonly exists the imbalance in the distribution of positive and negative samples. However, there are few existing methods that give specific consideration to this problem. In this paper, we proposed a new clustering-based LPIs prediction method using segmented k-mer frequencies and multi-space clustering (LPI-SKMSC). It was dedicated to handling the imbalance of positive and negative samples. We constructed segmented k-mer frequencies to obtain global and local features of lncRNA and protein sequences. Then, the multi-space clustering was applied to LPI-SKMSC. The convolutional neural network (CNN)-based encoders were used to map different features of a sample to different spaces. It used multiple spaces to jointly constrain the classification of samples. Finally, the distances between the output features of the encoder and the cluster center in each space were calculated. The sum of distances in all spaces was compared with the cluster radius to predict the LPIs. We performed cross-validation on 3 public datasets and LPI-SKMSC showed the best performance compared to other existing methods. Experimental results showed that LPI-SKMSC could predict LPIs more effectively when faced with imbalanced positive and negative samples. In addition, we illustrated that our model was better at uncovering potential lncRNA-protein interaction pairs.

An extensive overview of the role of lncRNAs generated from immune cells in the etiology of cancer

Long non-coding RNAs (lncRNAs) are involved in the control of critical tumor-suppressor and oncogenic pathways in cancer. These types of non-coding RNAs could affect both immune and cancer cells. The thorough analysis of lncRNAs derived from immune cells and the incorporation of new findings significantly advance our understanding of the complex role of lncRNAs in the context of cancer. This work highlights the promise of lncRNAs for translational therapeutic approaches while also establishing a solid foundation for comprehending the complex link between lncRNAs and cancer through a coherent narrative. The main findings of this article are that types of lncRNAs derived from immune cells, such as MM2P and MALAT1, can affect the behaviors of cancer cells, like invasion, angiogenesis, and proliferation. As research in this area grows, the therapeutic potential of targeting these lncRNAs offers promising opportunities for expanding our understanding of cancer biology and developing cutting-edge, precision-based therapies for cancer therapy.

Identification of modules and key genes associated with breast cancer subtypes through network analysis

Breast cancer is the most common malignancy in women around the world. Intratumor and intertumoral heterogeneity persist in mammary tumors. Therefore, the identification of biomarkers is essential for the treatment of this malignancy. This study analyzed 28,143 genes expressed in 49 breast cancer cell lines using a Weighted Gene Co-expression Network Analysis to determine specific target proteins for Basal A, Basal B, Luminal A, Luminal B, and HER2 ampl breast cancer subtypes. Sixty-five modules were identified, of which five were characterized as having a high correlation with breast cancer subtypes. Genes overexpressed in the tumor were found to participate in the following mechanisms: regulation of the apoptotic process, transcriptional regulation, angiogenesis, signaling, and cellular survival. In particular, we identified the following genes, considered as hubs: IFIT3, an inhibitor of viral and cellular processes; ETS1, a transcription factor involved in cell death and tumorigenesis; ENSG00000259723 lncRNA, expressed in cancers; AL033519.3, a hypothetical gene; and TMEM86A, important for regulating keratinocyte membrane properties, considered as a key in Basal A, Basal B, Luminal A, Luminal B, and HER2 ampl breast cancer subtypes, respectively. The modules and genes identified in this work can be used to identify possible biomarkers or therapeutic targets in different breast cancer subtypes.

Advancing drug-response prediction using multi-modal and -omics machine learning integration (MOMLIN): a case study on breast cancer clinical data

The inherent heterogeneity of cancer contributes to highly variable responses to any anticancer treatments. This underscores the need to first identify precise biomarkers through complex multi-omics datasets that are now available. Although much research has focused on this aspect, identifying biomarkers associated with distinct drug responders still remains a major challenge. Here, we develop MOMLIN, a multi-modal and -omics machine learning integration framework, to enhance drug-response prediction. MOMLIN jointly utilizes sparse correlation algorithms and class-specific feature selection algorithms, which identifies multi-modal and -omics-associated interpretable components. MOMLIN was applied to 147 patients' breast cancer datasets (clinical, mutation, gene expression, tumor microenvironment cells and molecular pathways) to analyze drug-response class predictions for non-responders and variable responders. Notably, MOMLIN achieves an average AUC of 0.989, which is at least 10% greater when compared with current state-of-the-art (data integration analysis for biomarker discovery using latent components, multi-omics factor analysis, sparse canonical correlation analysis). Moreover, MOMLIN not only detects known individual biomarkers such as genes at mutation/expression level, most importantly, it correlates multi-modal and -omics network biomarkers for each response class. For example, an interaction between ER-negative-HMCN1-COL5A1 mutations-FBXO2-CSF3R expression-CD8 emerge as a multimodal biomarker for responders, potentially affecting antimicrobial peptides and FLT3 signaling pathways. In contrast, for resistance cases, a distinct combination of lymph node-TP53 mutation-PON3-ENSG00000261116 lncRNA expression-HLA-E-T-cell exclusions emerged as multimodal biomarkers, possibly impacting neurotransmitter release cycle pathway. MOMLIN, therefore, is expected advance precision medicine, such as to detect context-specific multi-omics network biomarkers and better predict drug-response classifications.

lncRNA Biomarkers of Glioblastoma Multiforme

Long noncoding RNAs (lncRNAs) are RNA molecules of 200 nucleotides or more in length that are not translated into proteins. Their expression is tissue-specific, with the vast majority involved in the regulation of cellular processes and functions. Many human diseases, including cancer, have been shown to be associated with deregulated lncRNAs, rendering them potential therapeutic targets and biomarkers for differential diagnosis. The expression of lncRNAs in the nervous system varies in different cell types, implicated in mechanisms of neurons and glia, with effects on the development and functioning of the brain. Reports have also shown a link between changes in lncRNA molecules and the etiopathogenesis of brain neoplasia, including glioblastoma multiforme (GBM). GBM is an aggressive variant of brain cancer with an unfavourable prognosis and a median survival of 14-16 months. It is considered a brain-specific disease with the highly invasive malignant cells spreading throughout the neural tissue, impeding the complete resection, and leading to post-surgery recurrences, which are the prime cause of mortality. The early diagnosis of GBM could improve the treatment and extend survival, with the lncRNA profiling of biological fluids promising the detection of neoplastic changes at their initial stages and more effective therapeutic interventions. This review presents a systematic overview of GBM-associated deregulation of lncRNAs with a focus on lncRNA fingerprints in patients' blood.

Nanomaterials-Based Targeting of Long Non-Coding RNAs in Cancer: A Cutting-Edge Review of Current Trends

This review article spotlights the burgeoning potential of using nanotherapeutic strategies to target long non-coding RNAs (lncRNAs) in cancer cells. This updated discourse underlines the prominent role of lncRNAs in instigating cancer, facilitating its progression, and metastasis, validating lncRNAs' potential for being effective diagnostic biomarkers and therapeutic targets. The manuscript offers an in-depth examination of different strategies presently employed to modulate lncRNA expression and function for therapeutic purposes. Among these strategies, Antisense Oligonucleotides (ASOs), RNA interference (RNAi) technologies, and the innovative clustered regularly interspaced short palindromic repeats (CRISPR)-based gene editing tools garner noteworthy mention. A significant section of the review is dedicated to nanocarriers and their crucial role in drug delivery. These nanocarriers' efficiency in targeting lncRNAs in varied types of cancers is elaborated upon, validating the importance of targeted therapy. The manuscript culminates by reaffirming the promising prospects of targeting lncRNAs to enhance the accuracy of cancer diagnosis and improve treatment efficacy. Consequently, new paths are opened to more research and innovation in employing nanotherapeutic approaches against lncRNAs in cancer cells. Thus, this comprehensive manuscript serves as a valuable resource that underscores the vital role of lncRNAs and the various nano-strategies for targeting them in cancer treatment. Future research should also focus on unraveling the complex regulatory networks involving lncRNAs and identifying fundamental functional interactions to refine therapeutic strategies targeting lncRNAs in cancer.

LncRNAs exhibit subtype-specific expression, survival associations, and cancer-promoting effects in breast cancer

Long non-coding RNAs (lncRNAs) play important roles in cancer progression, influencing processes such as invasion, metastasis, and drug resistance. Their reported cell type-dependent expression patterns suggest the potential for specialized functions in specific contexts. In breast cancer, lncRNA expression has been associated with different subtypes, highlighting their relevance in disease heterogeneity. However, our understanding of lncRNA function within breast cancer subtypes remains limited, warranting further investigation. We conducted a comprehensive analysis using the TANRIC dataset derived from the TCGA-BRCA cohort, profiling the expression, patient survival associations and immune cell type correlations of 12,727 lncRNAs across subtypes. Our findings revealed subtype-specific associations of lncRNAs with patient survival, tumor infiltrating lymphocytes and other immune cells. Targeting of lncRNAs exhibiting subtype-specific survival associations and expression in a panel of breast cancer cells demonstrated a selective reduction in cell proliferation within their associated subtype, supporting subtype-specific functions of certain lncRNAs. Characterization of HER2 + -specific lncRNA LINC01269 and TNBC-specific lncRNA AL078604.2 showed nuclear localization and altered expression of hundreds of genes enriched in cancer-promoting processes, including apoptosis, cell proliferation and immune cell regulation. This work emphasizes the importance of considering the heterogeneity of breast cancer subtypes and the need for subtype-specific analyses to fully uncover the relevance and potential impact of lncRNAs. Collectively, these findings demonstrate the contribution of lncRNAs to the distinct molecular, prognostic, and cellular composition of breast cancer subtypes.

Therapeutic significance of long noncoding RNAs in estrogen receptor-positive breast cancer

About 70% of cases of breast cancer are compromised by Estrogen-positive breast cancer. Through its regulation of several processes, including cell proliferation, cell cycle progression, and apoptosis, Estrogen signaling plays a pivotal role in the genesis and progression of this particular kind of breast cancer. One of the best treatment strategies for treating Estrogen-positive breast cancer is blocking Estrogen signaling. However, patients' treatment failure is mainly caused by the emergence of resistance and metastases, necessitating the development of novel therapeutic targets. Numerous studies have shown long noncoding RNAs (lncRNAs) to play a role in Estrogen-mediated carcinogenesis. These lncRNAs interact with co-regulators and the Estrogen signaling cascade components, primarily due to Estrogen activation. Vimentin and E-cadherin are examples of epithelial-to-mesenchymal transition markers, and they regulate genes involved in cell cycle progression, such as Cyclins, to affect the growth, proliferation, and metastasis of Estrogen-positive breast cancer. Furthermore, a few of these lncRNAs contribute to developing resistance to chemotherapy, making them more desirable targets for enhancing results. Thus, to shed light on the creation of fresh approaches for treating this cancer, this review attempts to compile recently conducted studies on the relationship between lncRNAs and the advancement of Estrogen-positive breast cancer.

Unboxing the network among long non-coding RNAs and TGF-β signaling in cancer

Deeper analysis of molecular mechanisms arising in tumor cells is an unmet need to provide new diagnostic and therapeutic strategies to prevent and treat tumors. The transforming growth factor β (TGF-β) signaling has been steadily featured in tumor biology and linked to poor prognosis of cancer patients. One pro-tumorigenic mechanism induced by TGF-β is the epithelial-to-mesenchymal transition (EMT), which can initiate cancer dissemination, enrich the tumor stem cell population, and increase chemoresistance. TGF-β signals via SMAD proteins, ubiquitin ligases, and protein kinases and modulates the expression of protein-coding and non-coding RNA genes, including those encoding larger than 500 nt transcripts, defined as long non-coding RNAs (lncRNAs). Several reports have shown lncRNAs regulating malignant phenotypes by directly affecting epigenetic processes, transcription, and post-transcriptional regulation. Thus, this review aims to update and summarize the impact of TGF-β signaling on the expression of lncRNAs and the function of such lncRNAs as regulators of TGF-β signaling, and how these networks might impact specific hallmarks of cancer.

Harnessing the potential of long non-coding RNAs in breast cancer: from etiology to treatment resistance and clinical applications

Breast cancer (BC) is the most common malignancy among women and a leading cause of cancer-related deaths of females worldwide. It is a complex and molecularly heterogeneous disease, with various subtypes that require different treatment strategies. Despite advances in high-resolution single-cell and multinomial technologies, distant metastasis and therapeutic resistance remain major challenges for BC treatment. Long non-coding RNAs (lncRNAs) are non-coding RNAs with more than 200 nucleotides in length. They act as competing endogenous RNAs (ceRNAs) to regulate post-transcriptional gene stability and modulate protein-protein, protein-DNA, and protein-RNA interactions to regulate various biological processes. Emerging evidence suggests that lncRNAs play essential roles in human cancers, including BC. In this review, we focus on the roles and mechanisms of lncRNAs in BC progression, metastasis, and treatment resistance, and discuss their potential value as therapeutic targets. Specifically, we summarize how lncRNAs are involved in the initiation and progression of BC, as well as their roles in metastasis and the development of therapeutic resistance. We also recapitulate the potential of lncRNAs as diagnostic biomarkers and discuss their potential use in personalized medicine. Finally, we provide lncRNA-based strategies to promote the prognosis of breast cancer patients in clinical settings, including the development of novel lncRNA-targeted therapies.

Plasma Cell-Free Tumor Methylome as a Biomarker in Solid Tumors: Biology and Applications

DNA methylation is a fundamental mechanism of epigenetic control in cells and its dysregulation is strongly implicated in cancer development. Cancers possess an extensively hypomethylated genome with focal regions of hypermethylation at CPG islands. Due to the highly conserved nature of cancer-specific methylation, its detection in cell-free DNA in plasma using liquid biopsies constitutes an area of interest in biomarker research. The advent of next-generation sequencing and newer computational technologies have allowed for the development of diagnostic and prognostic biomarkers that utilize methylation profiling to diagnose disease and stratify risk. Methylome-based predictive biomarkers can determine the response to anti-cancer therapy. An additional emerging application of these biomarkers is in minimal residual disease monitoring. Several key challenges need to be addressed before cfDNA-based methylation biomarkers become fully integrated into practice. The first relates to the biology and stability of cfDNA. The second concerns the clinical validity and generalizability of methylation-based assays, many of which are cancer type-specific. The third involves their practicability, which is a stumbling block for translating technologies from bench to clinic. Future work on developing pan-cancer assays with their respective validities confirmed using well-designed, prospective clinical trials is crucial in pushing for the greater use of these tools in oncology.

LINC02086 promotes cell viability and inhibits cell apoptosis in breast cancer by sponging miR-6757-5p and up-regulating EPHA2

BACKGROUND

Long non-coding RNAs (lncRNAs) are critical regulators in the initiation and progression of breast cancer. Our study aims to characterize the functions of LINC02086 which few published in breast cancer and decipher the downstream molecular mechanisms.

METHODS

LINC02086 expression is tested in RNA-seq data from GEPIA database, tumor tissue samples from hospital patients and breast cancer cell lines. LINC02086 was silenced or overexpressed by lenti-virus-mediated shRNAs, or pLVX-Puro plasmids. Luciferase reporter assay and RNA pull-down assay were applied to study interactions between LINC02086, miR-6757-5p and ephrin type-A receptor 2 (EPHA2). LINC02086-silencing MCF-7 cells were injected into mice to establish xenograft animal models.

RESULTS

Using RNA-seq data, tumor tissue samples and breast cancer cells, LINC02086 was consistently found to be up-regulated in breast cancer, and correlated with poorer prognosis. LINC02086 knockdown decreased cell viability, promoted cell apoptosis and suppressed tumor growth. LINC02086 interacted with miR-6757-5p that interacted with EPHA2.LINC02086 expression was negatively correlated with miR-6757-5p expression (r = -0.5698, P < 0.001) but was positively correlated with EPHA2 expression (r = 0.5061, P < 0.001). miR-6757-5p expression was negatively correlated with EPHA2 expression (r = -0.5919, P < 0.001). LINC02086 regulated EPHA2 via miR-6757-5p. miR-6757-5p/EPHA2 axis was a mediator of the effect of LINC02086 on cell viability and apoptosis.

CONCLUSION

LINC02086 increases cell viability and decreases apoptotic cells in breast cancer by sponging miR-6757-5p to upregulate EPHA2. This study presents LINC02086/miR-6757-5p/EPHA2 axis as promising therapeutic targets for breast cancer intervention.

HOXC Cluster Antisense RNA 3, a Novel Long Non-Coding RNA as an Oncological Biomarker and Therapeutic Target in Human Malignancies

HOXC cluster antisense RNA 3 (HOXC-AS3) is a novel long noncoding RNA (lncRNA) that exhibits aberrant expression patterns in various cancer types. Its expression is closely related to clinicopathological features, demonstrating significant clinical relevance across multiple tumors. And HOXC-AS3 plays multifaceted roles in tumor progression, impacting cell proliferation, apoptosis, migration, invasion, epithelial-mesenchymal transition (EMT), autophagy, senescence, tumor growth, and metastasis. In this review, we summarized and comprehensively analyzed the expression and clinical significance of HOXC-AS3 as a diagnostic and prognostic biomarker for malignancies. Additionally, we presented an in-depth update on HOXC-AS3's functions and regulatory mechanisms in cancer pathogenesis. This narrative review underscores the importance of HOXC-AS3 as a promising lncRNA candidate in cancer research and its potential as a predictive biomarker and therapeutic target in clinical applications.

The role of long non-coding RNAs in breast cancer microenvironment

The tumor microenvironment (TME), which includes tumor cells, fibroblasts, endothelial cells, immune cells, and blood vessels, can affect tumor growth and metastasis. Studies have shown that tumor cells, fibroblasts, and macrophages can promote the development of tumors, while T and B cells can inhibit tumor progression. The crosstalk among different cells within the TME needs further study. Long non-coding RNAs (lncRNAs) are involved in biological processes, including cell proliferation, migration, and differentiation. The abnormal expression of certain lncRNAs is correlated with the progression of breast cancer and has been proven as diagnostic markers in various cancers, including breast cancer. In breast cancer, recent studies have shown that tumor cell- and non-tumor cell-derived lncRNAs can affect various facets of tumor progression, including growth, proliferation, and migration of tumor cells. Interestingly, in addition to being regulated by lncRNAs derived from tumor and non-tumor cells, the TME can regulate the expression of lncRNAs in tumor cells, fibroblasts, and macrophages, influencing their phenotype and function. However, the detailed molecular mechanisms of these phenomena remain unclear in the breast cancer microenvironment. Currently, many studies have shown that TME-associated lncRNAs are potential diagnostic and therapeutic targets for breast cancer. Considering that TME and lncRNAs can regulate each other, we summarize the role of lncRNAs in the breast cancer microenvironment and the potential of lncRNAs as valuable diagnostic markers.

Underexplored reciprocity between genome-wide methylation status and long non-coding RNA expression reflected in breast cancer research: potential impacts for the disease management in the framework of 3P medicine

Breast cancer (BC) is the most common female malignancy reaching a pandemic scale worldwide. A comprehensive interplay between genetic alterations and shifted epigenetic regions synergistically leads to disease development and progression into metastatic BC. DNA and histones methylations, as the most studied epigenetic modifications, represent frequent and early events in the process of carcinogenesis. To this end, long non-coding RNAs (lncRNAs) are recognized as potent epigenetic modulators in pathomechanisms of BC by contributing to the regulation of DNA, RNA, and histones' methylation. In turn, the methylation status of DNA, RNA, and histones can affect the level of lncRNAs expression demonstrating the reciprocity of mechanisms involved. Furthermore, lncRNAs might undergo methylation in response to actual medical conditions such as tumor development and treated malignancies. The reciprocity between genome-wide methylation status and long non-coding RNA expression levels in BC remains largely unexplored. Since the bio/medical research in the area is, per evidence, strongly fragmented, the relevance of this reciprocity for BC development and progression has not yet been systematically analyzed. Contextually, the article aims at:consolidating the accumulated knowledge on both-the genome-wide methylation status and corresponding lncRNA expression patterns in BC andhighlighting the potential benefits of this consolidated multi-professional approach for advanced BC management. Based on a big data analysis and machine learning for individualized data interpretation, the proposed approach demonstrates a great potential to promote predictive diagnostics and targeted prevention in the cost-effective primary healthcare (sub-optimal health conditions and protection against the health-to-disease transition) as well as advanced treatment algorithms tailored to the individualized patient profiles in secondary BC care (effective protection against metastatic disease). Clinically relevant examples are provided, including mitochondrial health control and epigenetic regulatory mechanisms involved.

m6A Modification Mediates Exosomal LINC00657 to Trigger Breast Cancer Progression Via Inducing Macrophage M2 Polarization

BACKGROUND

Exosome-mediated transfer of long noncoding RNAs (lncRNAs) is critical for the cell-cell crosstalk in the tumor microenvironment. Nevertheless, the role of breast cancer (BC) cell-derived exosomal lncRNA in macrophage polarization during the development of BC remains unclear.

METHODS

The key lncRNAs carried by BC cell-derived exosomes were identified by RNA-seq. CCK-8, flow cytometry, and transwell assay were conducted to analyze the role of LINC00657 in BC cells. In addition, immunofluorescence, qRT-PCR, western blot, and MeRIP-PCR were used to evaluate the function and underlying mechanism of exosomal LINC00657 in macrophage polarization.

RESULTS

LINC00657 was distinctly upregulated in BC-derived exosomes and it was associated with increased m6A methylation modification levels. In addition, the depletion of LINC00657 significantly diminished the proliferative activity, migration and invasion potential of BC cells, and it also accelerated cell apoptosis. Exosomal LINC00657 from MDA-MB-231 cells could facilitate macrophage M2 activation, thus stimulating BC development in turn. Furthermore, LINC00657 activated the TGF-β signaling pathway by sequestering miR-92b-3p in macrophages.

CONCLUSION

Exosomal LINC00657 secreted by BC cells could induce macrophage M2 activation, and these macrophages preferentially contributed to the malignant phenotype of BC cells. These results improve our understanding of BC and suggest a new therapeutic strategy for patients with BC.

A comprehensive review of the role of LINC00462 in human disorders

LINC00462; a long intergenic non-coding RNA located on chromosome chr13:48,576,973-48,590,587 is a member of long non-coding RNA (lncRNA) that is participated in different human disorders such as pancreatic cancer and hepatocellular carcinoma. LINC00462 can act as competing endogenous RNAs (ceRNAs), to sponge different MicroRNAs (miRNAs) such as miR-665. Dysregulation of LINC00462 can promote cancer development, progression, and metastasis. LINC00462 can also bind directly with genes and proteins to regulate different pathways, including STAT2/3 and PI3K/AKT pathways to affected tumor progression. In addition, aberrant LINC00462 levels can be important cancer-specific prognostic and diagnostic markers. In this review, we summarize the most recent studies on the role of LINC00462 in different disorders and demonstrated the role of LINC00462 in tumorigenesis.

Investigation of miR-133a, miR-637 and miR-944 genes expression and their relationship with PI3K/AKT signaling in women with breast cancer

PURPOSE

MicroRNAs (miRNAs) are regulatory molecules capable of positively or negatively regulating signaling pathways, and are involved in tumorigenesis as well as various aspects of cancer. The purpose of this study was to investigate the expression levels of miR-133a, miR-637, and miR-944 in serum and tumor tissues as well as their relationship with the expression level of phosphatidylinositol-3-kinase (PI3K) and protein kinase-B (AKT) genes and proteins along with their clinical significance in breast cancer.

METHODS

The expressions of miR-133a, miR-637, miR-944, PI3K, and AKT genes were examined in the tumor and tumor margin tissues of 40 patients with breast cancer, as well as the serum levels of miR-133a, miR-637, and miR-944 in these patients and 40 healthy groups by quantitative real-time PCR (qRT-PCR). PI3K and AKT proteins expression in tumor and tumor margin tissues were detected using immunohistochemistry (IHC).

RESULTS

The expression levels of miR-133a and miR-637 in the tumor tissue and serum of patients were lower than those in the tumor margin tissue and serum of the healthy group, respectively. In addition, the expression level of miR-944 in the tumor tissue was lower than that in the tumor margin tissue, but its expression increased in the serum of cancer patients compared to that in the healthy group. The expression of miR-637 was correlated with tumor location and Her2 receptors, and the expression of miR-944 was correlated with tumor location and family history. PI3K and AKT mRNA and protein levels were higher in the tumor tissues than in the tumor margin tissues (p < 0.05).

CONCLUSION

The results of our study revealed that miR-637 has a better diagnostic value in breast cancer than miR-133a and miR-944.

FLVCR1-AS1 and FBXL19-AS1: Two Putative lncRNA Candidates in Multiple Human Cancers

(1) Background: Mounting evidence supports the idea that one of the most critical agents in controlling gene expression could be long non-coding RNAs (lncRNAs). Upregulation of lncRNA is observed in the different processes related to pathologies, such as tumor occurrence and development. Among the crescent number of lncRNAs discovered, FLVCR1-AS1 and FBXL19-AS1 have been identified as oncogenes in many cancer progression and prognosis types, including cholangiocarcinoma, gastric cancer, glioma and glioblastoma, hepatocellular carcinoma, lung cancer, ovarian cancer, breast cancer, colorectal cancer, and osteosarcoma. Therefore, abnormal FBXL19-AS1 and FLVCR1-AS1 expression affect a variety of cellular activities, including metastasis, aggressiveness, and proliferation; (2) Methods: This study was searched via PubMed and Google Scholar databases until May 2022; (3) Results: FLVCR1-AS1 and FBXL19-AS1 participate in tumorigenesis and have an active role in impacting several signaling pathways that regulate cell proliferation, migration, invasion, metastasis, and EMT; (4) Conclusions: Our review focuses on the possible molecular mechanisms in a variety of cancers regulated by FLVCR1-AS1 and FBXL19-AS1. It is not surprising that there has been significant interest in the possibility that these lncRNAs might be used as biomarkers for diagnosis or as a target to improve a broader range of cancers in the future.

Migration/Differentiation-Associated LncRNA SENCR rs12420823*C/T: A Novel Gene Variant Can Predict Survival and Recurrence in Patients with Breast Cancer

Long non-coding RNAs (lncRNAs) have key roles in tumor development and the progress of many cancers, including breast cancer (BC). This study aimed to explore for the first time the association of the migration/differentiation-associated lncRNA SENCR rs12420823C/T variant with BC risk and prognosis. Genotyping was carried out for 203 participants (110 patients and 93 controls) using the TaqMan allelic discrimination technique. The corresponding clinicopathological data, including the recurrence/survival times, were analyzed with the different genotypes. After adjustment by age and risk factors, the T/T genotype carrier patients were more likely to develop BC under homozygote comparison (T/T vs. C/C: OR = 8.33, 95% CI = 2.44-25.0, p = 0.001), dominant (T/T-C/T vs. C/C: OR = 3.70, 95% CI = 1.72-8.33, p = 0.027), and recessive (T/T vs. C/T-C/C: OR = 2.17, 95% CI = 1.08-4.55, p < 0.001) models. Multivariate logistic regression analysis showed that the T/T genotype carriers were more likely to be triple-negative sub-type (OR = 2.66, 95% CI = 1.02-6.95, p = 0.046), at a higher risk of recurrence (OR = 3.57, 95% CI = 1.33-9.59, p = 0.012), and had short survival times (OR = 3.9, 95% CI = 1.52-10.05, p = 0.005). Moreover, Cox regression analysis supported their twofold increased risk of recurrence (HR = 2.14, 95% CI = 1.27-3.59, p = 0.004). Furthermore, the predictive nomogram confirmed the high weight for SENCR rs12420823*T/T and C/T genotypes in predicting recurrence within the first year. The Kaplan-Meier survival curve demonstrated low disease-free survival (T/T: 12.5 ± 1.16 months and C/T: 15.9 ± 0.86 months versus C/C: 22.3 ± 0.61 months, p < 0.001). In conclusion, the LncRNA SENCR rs12420823*C/T may be associated with an increased risk of BC in women and could be a promising genetic variant for predicting recurrence and survival.