LINC00511 knockdown enhances paclitaxel cytotoxicity in breast cancer via regulating miR-29c/CDK6 axis

The role of long non-coding RNAs in developing paclitaxel-resistant triple negative breast cancer: a systematic review

INTRODUCTION

Recent evidence supports the idea that long non-coding RNAs (lncRNAs) are significantly involved in chemoresistance of breast cancer. This study aimed to systematically review the emerging role of lncRNAs in paclitaxel (PTX) resistance in triple-negative breast cancer (TNBC). Furthermore, the review summarized potential targets and the underlying mechanisms of lncRNAs to induce or reverse the resistance of TNBC cells to PTX.

METHODS

The PubMed, Scopus, and Web of Science databases were searched for studies on lncRNAs involved in the resistance of TNBC cells to PTX using specific terms related to TNBC, lncRNAs, resistance, and paclitaxel. Relevant English articles published until November 2023, were systematically reviewed based on inclusion and exclusion criteria. Quality of the included studies was assessed using the Würzburg Methodological Quality Score (W-MeQS) by two independent authors.

RESULTS

A total of 95 publications were initially identified, and after applying the inclusion and exclusion criteria, 19 articles were included in this systematic review. These studies investigated the role of critical lncRNAs in PTX-resistant TNBC. Regulating the cell cycle and apoptosis, epithelial-to-mesenchymal transition, autophagy, and angiogenesis are the main mechanisms through which lncRNAs affect the resistance to PTX in TNBC.

CONCLUSION

This systematic review highlights the significant role of lncRNAs in promoting or inhibiting the resistance of TNBC cells to PTX. The lncRNAs with upregulated or downregulated expression in PTX-resistant TNBC may provide promising therapeutic targets to enhance the efficacy of chemotherapy.

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.

The Intergenic Type LncRNA (LINC RNA) Faces in Cancer with In Silico Scope and a Directed Lens to LINC00511: A Step toward ncRNA Precision

BACKGROUND

Long intergenic non-coding RNA, is one type of lncRNA, exerting various cellular activities, as does ncRNA, including the regulation of gene expression and chromatin remodeling. The abnormal expression of lincRNAs can induce or suppress carcinogenesis.

MAIN BODY

LincRNAs can regulate cancer progression through different mechanisms and are considered as potential drug targets. Genetic variations such as single nucleotide polymorphisms (SNPs) in lincRNAs may affect gene expression and messenger ribonucleic acid (mRNA) stability. SNPs in lincRNAs have been found to be associated with different types of cancer, as well. Specifically, LINC00511 has been known to promote the progression of multiple malignancies such as breast cancer, colorectal cancer, lung cancer, hepatocellular carcinoma, and others, making it a promising cancer prognostic molecular marker.

CONCLUSION

LincRNAs have been proved to be associated with different cancer types through various pathways. Herein, we performed a comprehensive literature and in silico databases search listing lncRNAs, lincRNAs including LINC00511, lncRNAs' SNPs, as well as LINC00511 SNPs in different cancer types, focusing on their role in various cancer types and mechanism(s) of action.

Long Noncoding RNAs in Taxane Resistance of Breast Cancer

Breast cancer is a common cancer in women and a leading cause of mortality. With the early diagnosis and development of therapeutic drugs, the prognosis of breast cancer has markedly improved. Chemotherapy is one of the predominant strategies for the treatment of breast cancer. Taxanes, including paclitaxel and docetaxel, are widely used in the treatment of breast cancer and remarkably decrease the risk of death and recurrence. However, taxane resistance caused by multiple factors significantly impacts the effect of the drug and leads to poor prognosis. Long noncoding RNAs (lncRNAs) have been shown to play a significant role in critical cellular processes, and a number of studies have illustrated that lncRNAs play vital roles in taxane resistance. In this review, we systematically summarize the mechanisms of taxane resistance in breast cancer and the functions of lncRNAs in taxane resistance in breast cancer. The findings provide insight into the role of lncRNAs in taxane resistance and suggest that lncRNAs may be used to develop therapeutic targets to prevent or reverse taxane resistance in patients with breast cancer.

Regulatory miRNAs, circRNAs and lncRNAs in cell cycle progression of breast cancer

Breast cancer is a complex and heterogeneous disease that poses a significant public health concern worldwide, and it remains a major challenge despite advances in treatment options. One of the main properties of cancer cells is the increased proliferative activity that has lost regulation. Dysregulation of various positive and negative modulators in the cell cycle has been identified as one of the driving factors of breast cancer. In recent years, non-coding RNAs have garnered much attention in the regulation of cell cycle progression, with microRNAs (miRNAs), circular RNAs (circRNAs), and long non-coding RNAs (lncRNAs) being of particular interest. MiRNAs are a class of highly conserved and regulatory small non-coding RNAs that play a crucial role in the modulation of various cellular and biological processes, including cell cycle regulation. CircRNAs are a novel form of non-coding RNAs that are highly stable and capable of modulating gene expression at posttranscriptional and transcriptional levels. LncRNAs have also attracted considerable attention because of their prominent roles in tumor development, including cell cycle progression. Emerging evidence suggests that miRNAs, circRNAs and lncRNAs play important roles in the regulation of cell cycle progression in breast cancer. Herein, we summarized the latest related literatures in breast cancer that emphasize the regulatory roles of miRNAs, circRNAs and lncRNAs in cell cycle progress of breast cancer. Further understanding of the precise roles and mechanisms of non-coding RNAs in breast cancer cell cycle regulation could lead to the development of new diagnostic and therapeutic strategies for breast cancer.

Long Non-Coding RNAs, Cell Cycle, and Human Breast Cancer

The long non-coding RNAs (lncRNAs) constitute an important class of the human transcriptome. The discovery of lncRNAs provided one of many unexpected results of the post-genomic era and uncovered a huge number of previously ignored transcriptional events. In recent years, lncRNAs are known to be linked with human diseases, with particular focus on cancer. Growing evidence has indicated that dysregulation of lncRNAs in breast cancer (BC) is strongly associated with the occurrence, development, and progress. Increasing numbers of lncRNAs have been found to interact with cell cycle progression and tumorigenesis in BC. The lncRNAs can exert their effect as a tumor suppressor or oncogene and regulate tumor development through direct or indirect regulation of cancer-related modulators and signaling pathways. What is more, lncRNAs are excellent candidates for promising therapeutic targets in BC due to the features of high tissue and cell-type specific expression. However, the underlying mechanisms of lncRNAs in BC still remain largely undefined. Here, we concisely summarize and sort out the current understanding of research progress in relationships of the roles for lncRNA in regulating the cell cycle. We also summarize the evidence for aberrant lncRNA expression in BC, and the potential for lncRNA to improve BC therapy is also discussed. Together, lncRNAs can be considered as exciting therapeutic candidates whose expression can be altered to impede BC progression.

Interplay between LncRNAs and microRNAs in Breast Cancer

(1) Although long noncoding RNAs (lncRNAs) are known to be precursors of microRNAs (miRNAs), they frequently act as competing endogoneous RNAs (ceRNAs), yet still their interplay with miRNA is not well known. However, their interaction with miRNAs may result in the modulation of miRNA action. (2) To determine the contribution of these RNA molecules in tumor resistance to chemotherapeutic drugs, it is essential to consider not only the oncogenic and tumor suppressive function of miRNAs but also the impact of lncRNAs on miRNAs. Therefore, we performed an extensive search in different databases including PubMed. (3) The present study concerns the interplay between lncRNAs and miRNAs in the regulatory post-transcriptional network and their impact on drugs used in the treatment of breast cancer. (4) Consideration of this interplay may improve the search for new drugs to circumvent chemoresistance.

CoNet: Efficient Network Regression for Survival Analysis in Transcriptome-Wide Association Studies—With Applications to Studies of Breast Cancer

Transcriptome-wide association studies (TWASs) aim to detect associations between genetically predicted gene expression and complex diseases or traits through integrating genome-wide association studies (GWASs) and expression quantitative trait loci (eQTL) mapping studies. Most current TWAS methods analyze one gene at a time, ignoring the correlations between multiple genes. Few of the existing TWAS methods focus on survival outcomes. Here, we propose a novel method, namely a COx proportional hazards model for NEtwork regression in TWAS (CoNet), that is applicable for identifying the association between one given network and the survival time. CoNet considers the general relationship among the predicted gene expression as edges of the network and quantifies it through pointwise mutual information (PMI), which is under a two-stage TWAS. Extensive simulation studies illustrate that CoNet can not only achieve type I error calibration control in testing both the node effect and edge effect, but it can also gain more power compared with currently available methods. In addition, it demonstrates superior performance in real data application, namely utilizing the breast cancer survival data of UK Biobank. CoNet effectively accounts for network structure and can simultaneously identify the potential effecting nodes and edges that are related to survival outcomes in TWAS.

linc00511 Knockdown Inhibits Lung Cancer Progression by Regulating miR-16-5p/MMP11

Lung cancer (LC) is a malignant tumor that extremely impairs people. According to numerous studies, long non-coding RNA (lncRNA) was inextricably involved in the advancement of LC. The work aspired to identify linc00511 expression in LC and to dig for the underlying mechanisms linc00511 regulated LC progression. Experimental outcomes revealed that linc00511 was obviously upregulated in LC, and linc00511 knockdown significantly impaired the malignant phenotype of LC cells in vitro. For an in-depth study on the contribution of linc00511 to LC advancement, it was disclosed that miR-16-5p had binding sites to the sequence of linc00511, which also inversely affected linc00511 expression in LC. Further experimental data demonstrated that miR-16-5p directly and negatively targeted matrix metallopeptidase 11 (MMP11). Also, rescue experiments displayed that miR-16-5p inhibition or MMP11 overexpressing offset the suppressive impacts of linc00511 silencing on LC progression. To sum up, our findings indicated that linc00511 performed a crucial role in facilitating LC progression, and mechanistic studies demonstrated that linc00511 aggravated LC progression via targeting the miR-16-5p/MMP11 axis.

The Mechanisms of lncRNA-Mediated Multidrug Resistance and the Clinical Application Prospects of lncRNAs in Breast Cancer

Simple Summary

Multidrug resistance (MDR) is a major cause of breast cancer (BC) chemotherapy failure. Long noncoding RNAs (lncRNAs) have been shown closely related to the chemoresistance of BC. In this work, the mechanisms of lncRNA-mediated MDR in BC were elaborated from eight sections, including apoptosis, autophagy, DNA repair, cell cycle, drug efflux, epithelial-mesenchymal transition, epigenetic modification and the tumor microenvironment. Additionally, we also discuss the clinical significance of lncRNAs, which may be biomarkers for diagnosis, therapy and prognosis.

Abstract

Breast cancer (BC) is a highly heterogeneous disease and presents a great threat to female health worldwide. Chemotherapy is one of the predominant strategies for the treatment of BC; however, multidrug resistance (MDR) has seriously affected or hindered the effect of chemotherapy. Recently, a growing number of studies have indicated that lncRNAs play vital and varied roles in BC chemoresistance, including apoptosis, autophagy, DNA repair, cell cycle, drug efflux, epithelial-mesenchymal transition (EMT), epigenetic modification and the tumor microenvironment (TME). Although thousands of lncRNAs have been implicated in the chemoresistance of BC, a systematic review of their regulatory mechanisms remains to be performed. In this review, we systematically summarized the mechanisms of MDR and the functions of lncRNAs mediated in the chemoresistance of BC from the latest literature. These findings significantly enhance the current understanding of lncRNAs and suggest that they may be promising prognostic biomarkers for BC patients receiving chemotherapy, as well as therapeutic targets to prevent or reverse chemoresistance.

Noncoding RNAs and their therapeutics in paclitaxel chemotherapy: Mechanisms of initiation, progression, and drug sensitivity

The identification of agents that can reverse drug resistance in cancer chemotherapy, and enhance the overall efficacy is of great interest. Paclitaxel (PTX) belongs to taxane family that exerts an antitumor effect by stabilizing microtubules and inhibiting cell cycle progression. However, PTX resistance often develops in tumors due to the overexpression of drug transporters and tumor-promoting pathways. Noncoding RNAs (ncRNAs) are modulators of many processes in cancer cells, such as apoptosis, migration, differentiation, and angiogenesis. In the present study, we summarize the effects of ncRNAs on PTX chemotherapy. MicroRNAs (miRNAs) can have opposite effects on PTX resistance (stimulation or inhibition) via influencing YES1, SK2, MRP1, and STAT3. Moreover, miRNAs modulate the growth and migration rates of tumor cells in regulating PTX efficacy. PIWI-interacting RNAs, small interfering RNAs, and short-hairpin RNAs are other members of ncRNAs regulating PTX sensitivity of cancer cells. Long noncoding RNAs (LncRNAs) are similar to miRNAs and can modulate PTX resistance/sensitivity by their influence on miRNAs and drug efflux transport. The cytotoxicity of PTX against tumor cells can also be affected by circular RNAs (circRNAs) and limitation is that oncogenic circRNAs have been emphasized and experiments should also focus on onco-suppressor circRNAs.

LncRNA polymorphisms and breast cancer risk

Breast cancer (BC) is the most prevalent cancer in females and the second reason of cancer-related mortality in females in the world. It is thought to be a complex interaction of variables like personal lifestyle, climate, genetics, and reproductive factors. Many polymorphisms have been linked to cancer in genome-wide association experiments, and they are linked to long non-coding RNAs (lncRNAs). LncRNAs, which have > 200 nucleotides in their transcripts, affect many biological processes, including differentiation, migration, apoptosis, cell cycle, and cell proliferation. Different lncRNAs with tumor suppressor and oncogenic roles have been shown to have elevated expression levels in the development of BC. Single-nucleotide polymorphisms (SNPs) in lncRNAs can affect the expression level, structure, and function of lncRNAs. LncRNA polymorphisms are predictive of cancer incidence, making them useful for early detection and customized therapy control. SNPs may affect genetic susceptibility to BC. This study was set to see whether there was a link between lncRNA polymorphisms and the risk of BC. Accordingly, the individual and combined genotypes of lncRNA-related variants could predict BC and clinical and care outcomes. However, further large-scale trials of diverse ethnic groups and comprehensive health records should be performed to validate the results. Furthermore, adequate functional assessments should be carried out to shed light on the etiology of BC. DATA AVAILABILITY: Not applicable.

Overexpression of miR-138-5p Sensitizes Taxol-Resistant Epithelial Ovarian Cancer Cells through Targeting Cyclin-Dependent Kinase 6

BACKGROUND

Ovarian cancer, one of the most malignant diseases in female, is associated with poor diagnosis and low 5-year survival rate. Taxol is a widely used chemotherapeutic drug for the treatment of ovarian cancer by targeting the microtubules of the mitotic spindle to induce cancer cell death. However, with the widespread clinical applications of Taxol, a large fraction of ovarian cancer patients developed drug resistance.

RESULTS

Here, we report miR-138-5p is significantly downregulated in epithelial ovarian cancer tissues compared with their matched normal ovarian tissues. Overexpression of miR-138-5p effectively sensitized ovarian cancer cells to Taxol. By establishing Taxol-resistant cell line from the epithelial ovarian cancer cell line, HO-8910, we found miR-138-5p was significantly downregulated in Taxol-resistant cells. Furthermore, overexpression of miR-138-5p dramatically overcame the chemoresistance of Taxol-resistant cells. Intriguingly, bioinformatic analysis indicated miR-138-5p had putative binding sites for cyclin-dependent kinase 6 (CDK6). This negative regulation was further verified from epithelial ovarian cancer tissues. Luciferase assay demonstrated miR-138-5p could directly bind to 3'UTR of CDK6. Importantly, silencing CDK6 expression by siRNA successfully increased the sensitivity of both parental and Taxol-resistant ovarian cancer cells. Finally, rescue experiments clearly elucidated restoration of CDK6 in miR-138-5p-overexpressing ovarian cancer cells successfully recovered the Taxol resistance.

CONCLUSION

In summary, these findings suggest important molecular mechanisms for the miR-138-5p-mediated Taxol sensitivity of ovarian cancer via directly targeting CDK6, suggesting miR-138-5p is an effective therapeutic target for the noncoding RNA-based anti-chemoresistance treatment.

MicroRNAs as a clue to overcome breast cancer treatment resistance

Breast cancer is the most frequent cancer in women worldwide. Despite the improvement in diagnosis and treatments, the rates of cancer relapse and resistance to therapies remain higher than desirable. Alterations in microRNAs have been linked to changes in critical processes related to cancer development and progression. Their involvement in resistance or sensitivity to breast cancer treatments has been documented by different in vivo and in vitro experiments. The most significant microRNAs implicated in modulating resistance to breast cancer therapies are summarized in this review. Resistance to therapy has been linked to cellular processes such as cell cycle, apoptosis, epithelial-to-mesenchymal transition, stemness phenotype, or receptor signaling pathways, and the role of microRNAs in their regulation has already been described. The modulation of specific microRNAs may modify treatment response and improve survival rates and cancer patients' quality of life. As a result, a greater understanding of microRNAs, their targets, and the signaling pathways through which they act is needed. This information could be useful to design new therapeutic strategies, to reduce resistance to the available treatments, and to open the door to possible new clinical approaches.

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.

LINC00511 facilitates Temozolomide resistance of glioblastoma cells via sponging miR-126-5p and activating Wnt/β-catenin signaling

Temozolomide (TMZ) is the first-line chemotherapy drug for glioblastoma (GBM) but acquired TMZ resistance is frequently observed. Thus, a TMZ resistant GBM cell line U87-R was established to search for potential long noncoding RNAs (lncRNAs) used in TMZ resistance. In our study, LINC00511 was identified as a TMZ resistance-associated lncRNA in U87-R cells by transcriptome RNA sequencing. The potential functions of LINC00511 were evaluated by quantitative real-time polymerase chain reaction, cell viability assay, colony formation assay, western blot, soft agar assay, flow cytometry, tumor xenograft model, immunofluorescence, sphere formation assay, fluorescent in situ hybridization, luciferase reporter assay, and RNA pull-down assay. We found that LINC00511 was upregulated in U87-R cells and GBM samples, and correlated with poor prognosis of GBM patients. Silencing LINC00511 impaired TMZ tolerance of U87-R cells, while LINC00511 overexpression increased TMZ resistance of sensitive GBM cells. Wnt/β-catenin signaling was activated in U87-R cells, and inhibiting Wnt/β-catenin signaling enhanced TMZ sensitivity. Furthermore, LINC00511 was mainly distributed in the cytoplasm of GBM cells and regulated Wnt/β-catenin activation by acting as a molecular sponge for miR-126-5p. Multiple genes of Wnt/β-catenin signaling such as DVL3, WISP1, and WISP2 were targeted by miR-126-5p. MiR-126-5p restoration impaired TMZ resistance of GBM cells. In conclusion, our results provided a novel insight into acquired TMZ resistance of GBM cells and suggested LINC00511 as a potential biomarker or therapeutic target for GBM patients.

Identification and Roles of miR-29b-1-3p and miR29a-3p-Regulated and Non-Regulated lncRNAs in Endocrine-Sensitive and Resistant Breast Cancer Cells

Despite improvements in the treatment of endocrine-resistant metastatic disease using combination therapies in patients with estrogen receptor α (ERα) primary tumors, the mechanisms underlying endocrine resistance remain to be elucidated. Non-coding RNAs (ncRNAs), including microRNAs (miRNA) and long non-coding RNAs (lncRNA), are targets and regulators of cell signaling pathways and their exosomal transport may contribute to metastasis. Previous studies have shown that a low expression of miR-29a-3p and miR-29b-3p is associated with lower overall breast cancer survival before 150 mos. Transient, modest overexpression of miR-29b1-3p or miR-29a-3p inhibited MCF-7 tamoxifen-sensitive and LCC9 tamoxifen-resistant cell proliferation. Here, we identify miR-29b-1/a-regulated and non-regulated differentially expressed lncRNAs in MCF-7 and LCC9 cells using next-generation RNA seq. More lncRNAs were miR-29b-1/a-regulated in LCC9 cells than in MCF-7 cells, including DANCR, GAS5, DSCAM-AS1, SNHG5, and CRND. We examined the roles of miR-29-regulated and differentially expressed lncRNAs in endocrine-resistant breast cancer, including putative and proven targets and expression patterns in survival analysis using the KM Plotter and TCGA databases. This study provides new insights into lncRNAs in endocrine-resistant breast cancer.

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

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

The role of long intergenic noncoding RNA 00511 in malignant tumors: a meta-analysis, database validation and review

Increasing studies suggested that long intergenic noncoding RNA 00511 (LINC00511) could facilitate the progression of various malignancies and correlates with prognosis of patients with malignant tumors. However, its clinical significance is still not completely clarified. Therefore, we performed a meta-analysis and bioinformatics analysis to further evaluate the correlation of LINC00511 expression level with prognosis and metastasis in patients with tumors. The pooled hazard ratio (HR) with 95% confidence interval (CI) was used to evaluate the prognostic significance of LINC00511 expression level. The pooled odds ratio (OR) with 95% CI was applied to assess the association between LINC00511 expression level and tumor metastasis. A total of 12 studies involving 1040 tumor patients were included in this meta-analysis. The pooled analyses suggested that higher LINC00511 expression level correlated with worse overall survival (OS) (HR = 1.93, 95% CI 1.49–2.49, P < 0.001) and higher incidence of lymph node metastasis (OR = 3.07, 95% CI 2.23–4.23, P < 0.001). Additionally, bioinformatics analysis based on TCGA datasets also showed that increased LINC00511 expression level may predict poor OS and disease-free survival (DFS) in patients with malignant tumors. Taken together, our finding suggested that high LINC00511 expression level may be correlated with poor prognosis and high incidence of metastasis. Nevertheless, further large-scale and high-quality studies are needed to validate our findings.

Regulation of Long Non-Coding RNAs by Plant Secondary Metabolites: A Novel Anticancer Therapeutic Approach

Simple Summary

Cancer is caused by the rapid and uncontrolled growth of cells that eventually lead to tumor formation. Genetic and epigenetic alterations are among the most critical factors in the onset of carcinoma. Phytochemicals are a group of natural compounds that play an essential role in cancer prevention and treatment. Long non-coding RNAs (lncRNAs) are potential therapeutic targets of bioactive phytochemicals, and these compounds could regulate the expression of lncRNAs directly and indirectly. Here, we critically evaluate in vitro and in vivo anticancer effects of phytochemicals in numerous human cancers via regulation of lncRNA expression and their downstream target genes.

Abstract

Long non-coding RNAs (lncRNAs) are a class of non-coding RNAs that play an essential role in various cellular activities, such as differentiation, proliferation, and apoptosis. Dysregulation of lncRNAs serves a fundamental role in the progression and initiation of various diseases, including cancer. Precision medicine is a suitable and optimal treatment method for cancer so that based on each patient’s genetic content, a specific treatment or drug is prescribed. The rapid advancement of science and technology in recent years has led to many successes in this particular treatment. Phytochemicals are a group of natural compounds extracted from fruits, vegetables, and plants. Through the downregulation of oncogenic lncRNAs or upregulation of tumor suppressor lncRNAs, these bioactive compounds can inhibit metastasis, proliferation, invasion, migration, and cancer cells. These natural products can be a novel and alternative strategy for cancer treatment and improve tumor cells’ sensitivity to standard adjuvant therapies. This review will discuss the antineoplastic effects of bioactive plant secondary metabolites (phytochemicals) via regulation of expression of lncRNAs in various human cancers and their potential for the treatment and prevention of human cancers.

C-Myc Signaling Pathway in Treatment and Prevention of Brain Tumors

Brain tumors are responsible for high morbidity and mortality worldwide. Several factors such as the presence of blood-brain barrier (BBB), sensitive location in the brain, and unique biological features challenge the treatment of brain tumors. The conventional drugs are no longer effective in the treatment of brain tumors, and scientists are trying to find novel therapeutics for brain tumors. In this way, identification of molecular pathways can facilitate finding an effective treatment. c-Myc is an oncogene signaling pathway capable of regulation of biological processes such as apoptotic cell death, proliferation, survival, differentiation, and so on. These pleiotropic effects of c-Myc have resulted in much fascination with its role in different cancers, particularly brain tumors. In the present review, we aim to demonstrate the upstream and down-stream mediators of c-Myc in brain tumors such as glioma, glioblastoma, astrocytoma, and medulloblastoma. The capacity of c-Myc as a prognostic factor in brain tumors will be investigated. Our goal is to define an axis in which the c-Myc signaling pathway plays a crucial role and to provide direction for therapeutic targeting in these signaling networks in brain tumors.

Role of non-coding RNAs in modulating the response of cancer cells to paclitaxel treatment

Paclitaxel is a chemotherapeutic substance that is administered for treatment of an extensive spectrum of human malignancies. In spite of its potent short-term effects against tumor cells, resistance to paclitaxel occurs in a number of patients precluding its long-term application in these patients. Non-coding RNAs have been shown to influence response of cancer cells to this chemotherapeutic agent via different mechanisms. Mechanistically, these transcripts regulate expression of several genes particularly those being involved in the apoptotic processes. Lots of in vivo and in vitro assays have demonstrated the efficacy of oligonucleotide-mediated microRNAs (miRNA)/ long non-coding RNAs (lncRNA) silencing in enhancement of response of cancer cells to paclitaxel. Therefore, targeted therapies against non-coding RNAs have been suggested as applicable modalities for combatting resistance to this agent. In the present review, we provide a summary of studies which assessed the role of miRNAs and lncRNAs in conferring resistance to paclitaxel.

Prognostic significance of long intergenic non-protein-coding RNA 511expression in malignant tumors: A systematic review and meta-analysis

BACKGROUND

A growing number of studies have suggested that the Long intergenic noncoding RNA 00511 (LINC00511) is aberrantly expressed in multiple malignancies and is related to patient survival. Herein, we conducted a systematic review and meta-analysis to comprehensively evaluate the prognostic significance of LINC00511 in human malignancies.

METHODS

Eligible studies published by March 11, 2020 were identified in 4 electronic databases including PubMed, EMBASE, Web of Science, and the Chinese National Knowledge Infrastructure. Hazard ratios and 95% confidence intervals (CIs) were used to evaluate the prognostic significance of LINC00511 expression in malignant tumors. The association between LINC00511 expression and cancer clinicopathologic features were assessed using Odds ratios (ORs) and CIs.

RESULTS

A total of 13 studies, comprising 1,053 patients, were included in the meta-analysis. The calculated hazard ratio was 2.00 (95% CI: 1.59-2.52, P < .000), suggesting that higher LINC00511 expression could predict poorer overall survival in patients with malignancies. Additionally, our statistical analysis indicated that elevated LINC00511 expression closely associated with bigger tumors (OR = 2.92, 95% CI 1.65-5.18, P < .000), higher incidence of lymph node metastasis (OR = 3.46, 95% CI 2.11-5.66, P < .000) and distant metastasis (OR = 2.40, 95% CI 1.14-5.05, P = .02), poorer differentiation (OR = 1.55, 95% CI 1.11-2.16, P = .01), as well as more advanced TNM stage (OR = 3.90, 95% CI 2.70-5.63, P < .000).

CONCLUSIONS

High LINC00511 expression may predict unfavorable prognosis in patients with malignancies. It should be further explored as a potential prognostic and therapeutic biomarker for human cancer.

HAND2-AS1 Works as a ceRNA of miR-3118 to Suppress Proliferation and Migration in Breast Cancer by Upregulating PHLPP2

Large quantities of long noncoding RNAs (lncRNAs) have been verified to exert vital functions in the process of breast cancer (BC). lncRNA heart and neural crest derivatives expressed 2-antisense RNA 1 (HAND2-AS1) was reported to suppress the development of several cancers. However, its detailed function in BC remained unclear. In the current study, HAND2-AS1 was discovered to be low expressed in BC cell lines, and overexpression of HAND2-AS1 could repress proliferation, migration, and invasion but facilitate apoptosis in BC cells. Moreover, HAND2-AS1 was found to act as a sponge of miR-3118 which was detected to be upregulated in BC cell lines. miR-3118 depletion could constrict the progression of BC. HAND-AS1 hindered the course of BC by reducing the expression of miR-3118. Besides, PHLPP2 was treated as a downstream target of miR-3118 under the selection of RNA pull-down assays. HAND2-AS1 inhibited the process of BC by enhancing expression of PHLPP2. In summary, our study testified that HAND2-AS1 suppressed BC growth by targeting the miR-3118/PHLPP2 axis, indicating that HAND2-AS1 could be regarded as a potential target for BC treatment.

Long non-coding RNA FAM133B-2 represses the radio-resistance of nasopharyngeal cancer cells by targeting miR-34a-5p/CDK6 axis

Long non-coding RNAs (lncRNAs) were found to play roles in various cancers, including nasopharyngeal carcinoma. In this study, we focused on the biological function of the lncRNA FAM133B-2 in the radio-resistance of nasopharyngeal carcinoma. The RNA-seq and qRT-PCR analysis showed that FAM133B-2 is highly expressed in the radio-resistant nasopharyngeal carcinoma cells. The following biochemical assays showed that FAM133B-2 represses the nasopharyngeal carcinoma radio-resistance and also affects the apoptosis and proliferation of nasopharyngeal carcinoma cells. Further investigations suggested that miR-34a-5p targets FAM133B-2 and also regulates the cyclin-dependent kinase 6 (CDK6). All these results suggested that the lncRNA FAM133B-2 might function as a competitive endogenous RNA (ceRNA) for miR-34a-5p in nasopharyngeal carcinoma radio-resistance, thus it may be regarded as a novel prognostic biomarker and therapeutic target in nasopharyngeal carcinoma diagnosis and treatment.

Highly penetrating nanobubble polymer enhances LINC00511-siRNA delivery for improving the chemosensitivity of triple-negative breast cancer

Ultrasound-mediated nanobubble destruction (UMND), which can utilize the physical energy of ultrasound irradiation to improve the transfer efficiency to target cells is becoming one of the most promising carriers for gene delivery. The purpose of this study was to establish cell-penetrating peptide (CPP)-loaded nanobubbles (CNBs) connected with long intergenic nonprotein coding RNA 00511-small interfering RNA (LINC00511-siRNA) and evaluate its feasibility for improving the chemosensitivity of triple-negative breast cancer in vitro. First, fluorescence imaging confirmed the loading of siLINC00511 on CNBs, and the CNBs-siLINC00511 were characterized by the Zetasizer Nano ZS90 analyzer and transmission electron microscopy. Next, cell counting kit 8 assay was used to detect the inhibitory activity of cisplatin on the proliferation of MDA-MB-231 cells, and the 50% inhibition concentration value before and after transfer was calculated. Finally, the silencing effect of siLINC00511 was evaluated in vitro using an apoptosis assay, transwell assay, real time-PCR and western blotting. UMND combined with CNBs could effectively transfer the siRNA to MDA-MB-231 cells, thus evidently reducing the expression of LINC00511. Furthermore, inhibitory activity of cisplatin on MDA-MB-231 cells was enhanced after downregulation of LINC00511 expression. Downregulation of LINC00511 alters expression of cell cycle-related (CDK 6) and apoptosis-related (Bcl-2 and Bax) proteins in MDA-MB-231 cells. These results suggested that siRNA-CNBs may be an ideal vector for the treatment of tumors, with high efficiency RNA interference under the combined action of UMND. It may provide a new therapeutic method for triple negative breast cancer.

LINC00511 as a prognostic biomarker for human cancers: a systematic review and meta-analysis

BACKGROUND

Long intergenic non-coding RNA 00511 (LINC00511) is highly expressed in diverse cancers and has a correlation with poor clinical outcomes for cancer patients. In view of contradictory data among published data, we aim to evaluate the prognostic role of LINC00511 for cancer patients.

METHODS

In the present study, a meta-analysis of related studies has been performed to investigate the prognostic significance of LINC00511 in cancer patients. Relevant studies published before December 22, 2019 were systematically searched online in PubMed, EMBASE, Web of Science, and the Cochrane Library databases. The relationship between LINC00511 expression and cancer patients' survival, including overall survival (OS), disease-free survival (DFS)/relapse-free survival (RFS) and progression-free survival (PFS), was evaluated using pooled hazard ratios (HRs) with their corresponding 95% confidence intervals (CIs). The association between LINC00511 expression and clinicopathological features was assessed using odd ratios (ORs) and their corresponding 95% CIs.

RESULTS

A total of 14 eligible studies with 1883 patients were enrolled in the present meta-analysis. The results demonstrated that elevated expression of LINC00511 was significantly associated with poor OS (HR = 2.62; 95% CI: 2.00-3.45; p <  0.001), PFS (HR = 1.80; 95% CI: 1.29-2.51; p = 0.001) and DFS/RFS (HR = 2.90; 95% CI: 1.04-8.12; p = 0.04). Additionally, High LINC00511 expression was associated with large tumor size (OR = 3.10; 95% CI: 1.97-4.86; p <  0.00001), lymph node metastasis (OR = 3.11; 95% CI: 2.30-4.21; p <  0.00001), advanced clinical stage (OR = 3.95; 95% CI: 2.68-5.81; p <  0.00001), distant metastasis (OR = 2.39; 95% CI: 1.16-4.93; p = 0.02), and disease recurrence (OR = 4.62; 95% CI: 2.47-8.65; p <  0.00001). Meanwhile, no correlation was found between LINC00511 expression and age, gender, and histological grade. These findings were consolidated by the results of bioinformatics analysis.

CONCLUSIONS

Based on our findings, LINC00511 may serve as a novel prognostic biomarker for cancer patients.

Long Non-Coding RNAs in Drug Resistance of Breast Cancer

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

Long Non-coding RNA RP11-480I12.5 Promotes the Proliferation, Migration, and Invasion of Breast Cancer Cells Through the miR-490-3p-AURKA-Wnt/β-Catenin Axis

Background: RP11-480I12. 5 is a newly identified long non-coding RNA (lncRNA) that has never been studied in breast cancer (BC). The biological function of RP11-480I12.5 in breast carcinoma and its underlying mechanism are still unknown.

Methods: We scanned The Cancer Genome Atlas (TCGA) database and identified RP11-480I12.5 as one of the most dysregulated lncRNAs. The level of RP11-480I12.5 was assessed in BC tissue samples and BC cell lines. The prognostic value of RP11-480I12.5 expression was assessed using the Kaplan–Meier method. The biological influence of RP11-480I12.5 on BC cell lines was studied using proliferation and Transwell migration and invasion assays.

Results: RP11-480I12.5 expression was upregulated in data from both the TCGA database and our own database. Moreover, Kaplan–Meier and Cox proportional hazard analyses indicated that high RP11-480I12.5 expression was related to poor overall survival. Moreover, RP11-480I12.5 promoted the proliferation, migration, and invasion of BC. RP11-480I12.5 promoted the expression of AURKA and the activation of the downstream Wnt/β-catenin pathway by sponging the microRNA (miRNA) miR-490-3p.

Conclusion: Taken together, our results indicate that RP11-480I12.5 is associated with tumor progression in BCs. Our findings indicate that the lncRNA RP11-480I12.5 promotes the proliferation, migration, and invasion of BC cells through the miR-490-3p-AURKA-Wnt/β-catenin axis, which may serve as a therapeutic target in the future.

Long Intergenic Non-protein Coding RNA 511 in Cancers

Background: Long intergenic non-protein coding RNA 511 (LINC00511) is upregulated in diverse cancers and involved in prognosis. This study aimed to evaluate the prognostic profile of LINC00511 in cancer patients. Methods: Published studies evaluating the prognosis of LINC00511 in patients with different cancers were identified from Medline, Embase, and Web of Science. Analysis of the association between LINC00511 and clinicopathological characteristics was conducted. GEPIA was used to validation and functional analysis and LnCeVar was used to get genomic variations. Results: We eventually included 9 studies, and the combined results showed LINC00511 was significantly associated with decreased OS (HR = 3.18, 95% CI = 2.29 ~ 4.42, P < 0.001) albeit with mild heterogeneity (I 2 = 58.1%, P h = 0.014), similarly in cancer type subgroups: breast cancer, digestive system cancer, and cervical cancer (all P < 0.001). There is no publication bias and meta-regression indicated follow-up time maybe heterogeneity of the results (P = 0.008). Additionally, LINC00511 appeared to be correlated with age, clinical stage, tumor size, and lymph node metastasis. Those findings were confirmed in GEPIA. Through LnCeVars, gene ontology and functional pathways were enriched, and dysregulated hallmarks and related ceRNA network of LINC00511 were disturbed. Conclusions: LINC00511 could be predictive of poor OS and lymph node metastasis in multiple cancers, in another word, LINC00511 serves as an unfavorable prognostic factor, and its mechanism is related to ceRNA.

Identification of a Novel Eight-lncRNA Prognostic Signature for HBV-HCC and Analysis of Their Functions Based on Coexpression and ceRNA Networks

Studies have demonstrated the prognosis potential of long noncoding RNAs (lncRNAs) for hepatocellular carcinoma (HCC), but specific lncRNAs for hepatitis B virus- (HBV-) related HCC have rarely been reported. This study was aimed at identifying a lncRNA prognostic signature for HBV-HCC and exploring their underlying functions. The sequencing dataset was collected from The Cancer Genome Atlas database as the training set, while the microarray dataset was obtained from the European Bioinformatics Institute database (E-TABM-36) as the validation set. Univariate and multivariate Cox regression analyses identified that eight lncRNAs (TSPEAR-AS1, LINC00511, LINC01136, MKLN1-AS, LINC00506, KRTAP5-AS1, ZNF252P-AS1, and THUMPD3-AS1) were significantly associated with overall survival (OS). These eight lncRNAs were used to construct a risk score model. The Kaplan-Meier survival curve results showed that this risk score can significantly differentiate the OS between the high-risk group and the low-risk group. Receiver operating characteristic curve analysis demonstrated that this risk score exhibited good prediction effectiveness (area under the curve (AUC) = 0.990 for the training set; AUC = 0.903 for the validation set). Furthermore, this lncRNA risk score was identified as an independent prognostic factor in the multivariate analysis after adjusting other clinical characteristics. The crucial coexpression (LINC00511-CABYR, THUMPD3-AS1-TRIP13, LINC01136-SFN, LINC00506-ANLN, and KRTAP5-AS1/TSPEAR-AS1/MKLN1-AS/ZNF252P-AS1-MC1R) or competing endogenous RNA (THUMPD3-AS1-hsa-miR-450a-TRIP13) interaction axes were identified to reveal the possible functions of lncRNAs. These genes were enriched into cell cycle-related biological processes or pathways. In conclusion, our study identified a novel eight-lncRNA prognosis signature for HBV-HCC patients and these lncRNAs may be potential therapeutic targets.

The Roles of Cyclin-Dependent Kinases in Cell-Cycle Progression and Therapeutic Strategies in Human Breast Cancer

Cyclin-dependent kinases (CDKs) are serine/threonine kinases whose catalytic activities are regulated by interactions with cyclins and CDK inhibitors (CKIs). CDKs are key regulatory enzymes involved in cell proliferation through regulating cell-cycle checkpoints and transcriptional events in response to extracellular and intracellular signals. Not surprisingly, the dysregulation of CDKs is a hallmark of cancers, and inhibition of specific members is considered an attractive target in cancer therapy. In breast cancer (BC), dual CDK4/6 inhibitors, palbociclib, ribociclib, and abemaciclib, combined with other agents, were approved by the Food and Drug Administration (FDA) recently for the treatment of hormone receptor positive (HR+) advanced or metastatic breast cancer (A/MBC), as well as other sub-types of breast cancer. Furthermore, ongoing studies identified more selective CDK inhibitors as promising clinical targets. In this review, we focus on the roles of CDKs in driving cell-cycle progression, cell-cycle checkpoints, and transcriptional regulation, a highlight of dysregulated CDK activation in BC. We also discuss the most relevant CDK inhibitors currently in clinical BC trials, with special emphasis on CDK4/6 inhibitors used for the treatment of estrogen receptor-positive (ER+)/human epidermal growth factor 2-negative (HER2−) M/ABC patients, as well as more emerging precise therapeutic strategies, such as combination therapies and microRNA (miRNA) therapy.

Linc00511 Indicates A Poor Prognosis Of Liver Hepatocellular Carcinoma

Objective

To uncover the specific function of linc00511 in the progression of liver hepatocellular carcinoma (LIHC) and the underlying mechanism.

Patients and methods

GEPIA dataset containing 9736 LIHC samples and 857 normal samples were downloaded from TCGA. Expression pattern and prognostic potential of linc00511 in LIHC were analyzed. Subsequently, expression level of linc00511 in LIHC tissues collected in our hospital and cell lines were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Differential expressions of linc00511 in LIHC with different tumor grades and metastatic status were compared. After transfection of si-linc00511, proliferative and migratory changes in Huh7 and Hep3B cells were assessed by cell counting kit-8 (CCK-8), 5-ethynyl-2ʹ-deoxyuridine (EdU) and Transwell assay. Lastly, Pearson correlation analysis and qRT-PCR were conducted to investigate the interaction between linc00511 and miR-29c.

Results

Linc00511 was upregulated in LIHC tissues and cell lines. Its level was positively correlated to TNM staging, lymphatic metastasis and poor prognosis in LIHC patients. Knockdown of linc00511 attenuated proliferative and migratory abilities in Huh7 and Hep3B cells. In addition, miR-29c was downregulated in LIHC and negatively linked to linc00511 level. A negative interaction between linc00511 and miR-29c could be a regulatory feedback influencing the progression of LIHC.

Conclusion

Linc00511 accelerates the proliferation and migration in LIHC, thus aggravating tumor progression. Meanwhile, linc00511 could be utilized as a hallmark predicting poor prognosis in LIHC patients.

LINC00511 promotes the malignant phenotype of clear cell renal cell carcinoma by sponging microRNA-625 and thereby increasing cyclin D1 expression

The expression pattern and detailed roles of long noncoding RNA LINC00511 in clear cell renal cell carcinoma (ccRCC) remain unknown. We measured LINC00511 expression in ccRCC. We clarified the clinical characteristics associated with LINC00511 in ccRCC. We examined the biological roles of LINC00511 in the progression of ccRCC, and we identified the potential mechanisms involved. LINC00511 was upregulated in ccRCC tissues and cell lines. High LINC00511 expression significantly correlated with TNM classification, lymph node metastasis, and short overall survival among patients with ccRCC. Additionally, LINC00511 knockdown restricted ccRCC cell proliferation, colony formation, and metastasis in vitro; accelerated cell cycle arrest at G0–G1 and apoptosis in vitro; and decreased tumor growth in vivo. Investigation of the mechanism revealed that LINC00511 directly interacted with microRNA-625 (miR-625), and the inhibitory effects of the LINC00511 knockdown on malignant characteristics were neutralized by miR-625 silencing. Furthermore, cyclin D1 (CCND1) was identified as a direct target of miR-625 in ccRCC cells. The tumor-suppressive activity of miR-625 upregulation on ccRCC cells was reversed by CCND1 reintroduction. In conclusion, LINC00511 serves as a competing endogenous RNA that regulates CCND1 expression by sponging miR-625 in ccRCC. Hence, the LINC00511/miR-625/CCND1 pathway might be a promising therapeutic target in ccRCC.