Long non‐coding RNA FEZF1‐AS1 promotes breast cancer stemness and tumorigenesis via targeting miR‐30a/Nanog axis

The Role of lncRNA FEZF1-AS1 in Colorectal Cancer Progression Via the P53 Signaling Pathway

Long noncoding RNAs (lncRNAs) have emerged as critical regulators in the development of colorectal cancer (CRC). Previous studies indicate that lncRNA FEZF1-AS1 is highly expressed in CRC, but its role in modulating CRC via the P53 signaling pathway remains unclear. In this study, we found that FEZF1-AS1 promotes the growth of the CRC cell line (HCT116) and drives epithelial-mesenchymal transition (EMT) through the P53 signaling pathway. Our data showed that FEZF1-AS1 expression is significantly upregulated in HCT116, and elevated levels of FEZF1-AS1 are associated with poor prognosis in patients with CRC. In addition, the knockdown of FEZF1-AS1 markedly inhibited the proliferation of HCT116 by inducing cell cycle arrest. Knockdown of FEZF1-AS1 depletion also led to apoptosis in CRC cells by suppressing the P53 signaling pathway and EMT, thereby reducing their viability, proliferation, migration, and invasion. In summary, this study confirmed that FEZF1-AS1 regulates the growth of junction HCT116 through P53 signaling pathway and inhibiting EMT, providing new insights for the potential therapeutic strategies against CRC.

LncRNA FEZF1-AS1 promotes pulmonary fibrosis via up-regulating EZH2 and targeting miR-200c-3p to regulate the ZEB1 pathway

The role and detailed mechanisms of lncRNAs in idiopathic pulmonary fibrosis (IPF) are not fully understood. qPCR was conducted to verify lncRNA FEZF1-AS1 expression in the transforming growth factor-beta 1 (TGF-β1)-stimulated human lung fibroblasts (HLF) and A549. The EMT-related proteins were performed by western blotting. Cell proliferation, migration, and transition were detected by CCK-8, colony formation, wound-healing and transwell assays. A dual-luciferase reporter assay was conducted to validate the target relationship of FEZF1-AS1 and miR-200c-3p. FEZF1-AS1 is highly expressed in the fibrotic A549 and HLF. in vitro experiments revealed that FEZF1-AS1 facilitates cell proliferation, migration and invasion. Knockdown of FEZF1-AS1 attenuated TGF-b1-induced fibrogenesis both in vitro. Moreover, silencing FEZF1-AS1 inhibited fibrogenesis through modulation of miR-200c-3p. In addition, inhibition of miR-200c-3p promoted fibrogenesis by regulation of Zinc finger E-box binding homeobox 1 (ZEB1). Mechanistically, FEZF1-AS1 promoted lung fibrosis by acting as a competing endogenous RNA (ceRNA) for miR-200c-3p. FEZF1-AS1 silencing increased the expression and activity of miR-200c-3p to inhibit ZEB1 and alleviate lung fibrogenesis in A549 and HLF. In addition, our study showed that FEZF1-AS1 can regulate enhancer of zeste homolog2 (EZH2) to upregulate fibrosis-related proteins and promote lung fibrosis. In summary, the results of our study revealed the pulmonary fibrogenic effect of FEZF1-AS1 in cellular experiments, demonstrating the potential roles and mechanisms of the FEZF1-AS1/miR-200c-3p/ZEB1 and FEZF1-AS1/EZH2 pathways, which provides a novel and potential therapeutic target to lung fibrosis.

Competing endogenous RNAs regulatory crosstalk networks: The messages from the RNA world to signaling pathways directing cancer stem cell development

Cancer stem cells (CSCs) are one of the cell types that account for cancer heterogeneity. The cancer cells arrest in G0 and generate non-CSC progeny through self-renewal and pluripotency, resulting in tumor recurrence, metastasis, and resistance to chemotherapy. They can stimulate tumor relapse and re-grow a metastatic tumor. So, CSCs is a promising target for eradicating tumors, and developing an anti-CSCs therapy has been considered. In recent years competing endogenous RNA (ceRNA) has emerged as a significant class of post-transcriptional regulators that affect gene expression via competition for microRNA (miRNA) binding. Furthermore, aberrant ceRNA expression is associated with tumor progression. Recent findings show that ceRNA network can cause tumor progression through the effect on CSCs. To overcome therapeutic resistance due to CSCs, we need to improve our current understanding of the mechanisms by which ceRNAs are implicated in CSC-related relapse. Thus, this review was designed to discuss the role of ceRNAs in CSCs' function. Targeting ceRNAs may open the path for new cancer therapeutic targets and can be used in clinical research.

New insights into the interaction between m6A modification and lncRNA in cancer drug resistance

Drug resistance is perhaps the greatest obstacle in improving outcomes for cancer patients, leading to recurrence, progression and metastasis of various cancers. Exploring the underlying mechanism worth further study. N6-methyladenosine (m6A) is the most common RNA modification found in eukaryotes, playing a vital role in RNA translation, transportation, stability, degradation, splicing and processing. Long noncoding RNA (lncRNA) refers to a group of transcripts that are longer than 200 nucleotides (nt) and typically lack the ability to code for proteins. LncRNA has been identified to play a significant role in regulating multiple aspects of tumour development and progression, including proliferation, metastasis, metabolism, and resistance to treatment. In recent years, a growing body of evidence has emerged, highlighting the crucial role of the interplay between m6A modification and lncRNA in determining the sensitivity of cancer cells to chemotherapeutic agents. In this review, we focus on the recent advancements in the interaction between m6A modification and lncRNA in the modulation of cancer drug resistance. Additionally, we aim to explore the underlying mechanisms involved in this process. The objective of this review is to provide valuable insights and suggest potential future directions for the reversal of chemoresistance in cancer.

LncRNA WAC-AS1 promotes osteosarcoma Metastasis and stemness by sponging miR-5047 to upregulate SOX2

Cancer stemness and osteosarcoma (OS) malignant progression are closely associated. However, the molecular mechanisms underlying this association have not been fully demonstrated. Long noncoding RNAs (lncRNAs) are an intriguing class of widely prevalent endogenous RNAs involved in OS progression, the vast majority of which have not been characterized functionally. Here, we identified tumor promoter lncRNA WAC-AS1 to be highly expressed in OS tumors and associated with worse survival. Further analysis revealed that WAC-AS1 increased tumorsphere formation of OS cells and promoted metastasis, as confirmed by cell proliferation, transwell and wound healing assays. MiR-5047 was identified as a downstream target of WAC-AS1. Subsequently, based on bioinformatics analysis, RIP assay and luciferase reporter assay, SOX2 mRNA was verified as a target of miR-5047. WAC-AS1 enhanced OS cell proliferation and stemness via acting as a ceRNA by binding to miR-5047, thereby increasing SOX2 expression. In addition, SOX2 bound to the promoter region of WAC-AS1 and promoted its transcription, thereby forming a positive feedback loop to regulate OS malignancy. Taken together, our findings show WAC-AS1 is a tumor promoter and a key regulator of OS cell stemness and metastasis via a miR-5047/SOX2 axis.

Crosstalk between long noncoding RNA and microRNA in Cancer

miRNAs and lncRNAs play a central role in cancer-associated gene regulations. The dysregulated expression of lncRNAs has been reported as a hallmark of cancer progression, acting as an independent prediction marker for an individual cancer patient. The interplay of miRNA and lncRNA decides the variation of tumorigenesis that could be mediated by acting as sponges for endogenous RNAs, regulating miRNA decay, mediating intra-chromosomal interactions, and modulating epigenetic components. This paper focuses on the influence of crosstalk between lncRNA and miRNA on cancer hallmarks such as epithelial-mesenchymal transition, hijacking cell death, metastasis, and invasion. Other cellular roles of crosstalks, such as neovascularization, vascular mimicry, and angiogenesis were also discussed. Additionally, we reviewed crosstalk mechanism with specific host immune responses and targeting interplay (between lncRNA and miRNA) in cancer diagnosis and management.

Up-regulation of BOK-AS1, FAM215A and FEZF1-AS1 lncRNAs and their potency as moderate diagnostic biomarkers in gastric cancer

BACKGROUND

Gastric cancer is the fifth most frequent cancer worldwide and the fourth leading cause of death from cancer, a complex multifactorial neoplasm. LncRNAs are regulatory RNA molecules larger than 200 nucleotides, which can have profound effects on the oncogenic process of various types of cancer. Therefore, these molecules can be used as diagnostic and therapeutic biomarkers. This study aimed to determine the differences in BOK-AS1, FAM215A, and FEZF1-AS1 gene expression between tumor tissue and adjacent healthy non-tumor tissue of gastric cancer (GC) patients.

METHODS

In this study one hundred pairs of cancerous and non-cancerous marginal tissues were gathered. Next, RNA extraction and cDNA synthesis were achieved for all of the samples. Then, the qRT-PCR was performed to measure the expression of BOK-AS1, FAM215A and FEZF1-AS1 genes.

RESULTS

All BOK-AS1, FAM215A and FEZF1-AS1 genes showed significantly increased expression in tumor tissues compared with non-tumor tissues. The outcome of the ROC analysis demonstrated that BOK-AS1, FAM215A, and FEZF1-AS1 may act as mean biomarkers with AUC of 0.7368, 0.7163 and 0.7115, specificity of 64%, 61% and 59%, and sensitivity of 74%, 70%, and 74% respectively.

CONCLUSION

Based on the increased expression of the BOK-AS1, FAM215A and FEZF1-AS1 genes in GC patients, this study suggests that these genes may function as oncogenic factors. Furthermore, the mentioned genes can be considered as intermediate biomarkers for diagnosis and treatment of gastric cancer. In addition, no association between these genes and clinicopathological features was observed.

Long non-coding RNAs in breast cancer stem cells

Breast cancer, one of the most commonly diagnosed cancers worldwide, is a heterogeneous disease with high rates of recurrence and metastasis that contribute to its high mortality rate. Breast cancer stem cells (BCSCs) are a small but significant subset of heterogeneous breast cancer cells that possess stem cell characteristics such as self-renewal and differentiation abilities that may drive metastasis and recurrence. Long non-coding RNAs (lncRNAs) are a class of RNAs that are longer than 200 nucleotides in length and do not possess protein-coding properties. An increasing number of studies have shown that some lncRNAs are abnormally expressed in BCSCs, and have great biological significance in the occurrence, progression, invasion, and metastasis of various cancers. However, the importance of lncRNAs, as well as the molecular mechanisms that regulate and promote the stemness of BCSCs, are still poorly understood. In the current review, we aim to summarize recent studies that highlight the role of lncRNAs in tumor occurrence and progression through BCSCs. In addition, the utility of lncRNAs as biomarkers of breast cancer progression, and their potential use as therapeutic targets for treatment of breast cancer, will be discussed.

HMGA2 regulation by miRNAs in cancer: affecting cancer hallmarks and therapy response

High mobility group A 2 (HMGA2) is a protein that modulates the structure of chromatin in the nucleus. Importantly, aberrant expression of HMGA2 occurs during carcinogenesis, and this protein is an upstream mediator of cancer hallmarks including evasion of apoptosis, proliferation, invasion, metastasis, and therapy resistance. HMGA2 targets critical signaling pathways such as Wnt/β-catenin and mTOR in cancer cells. Therefore, suppression of HMGA2 function notably decreases cancer progression and improves outcome in patients. As HMGA2 is mainly oncogenic, targeting expression by non-coding RNAs (ncRNAs) is crucial to take into consideration since it affects HMGA2 function. MicroRNAs (miRNAs) belong to ncRNAs and are master regulators of vital cell processes, which affect all aspects of cancer hallmarks. Long ncRNAs (lncRNAs) and circular RNAs (circRNAs), other members of ncRNAs, are upstream mediators of miRNAs. The current review intends to discuss the importance of the miRNA/HMGA2 axis in modulation of various types of cancer, and mentions lncRNAs and circRNAs, which regulate this axis as upstream mediators. Finally, we discuss the effect of miRNAs and HMGA2 interactions on the response of cancer cells to therapy. Regarding the critical role of HMGA2 in regulation of critical signaling pathways in cancer cells, and considering the confirmed interaction between HMGA2 and one of the master regulators of cancer, miRNAs, targeting miRNA/HMGA2 axis in cancer therapy is promising and this could be the subject of future clinical trial experiments.

Metformin and long non-coding RNAs in breast cancer

Breast cancer (BC) is the second most common cancer and cause of death in women. In recent years many studies investigated the association of long non-coding RNAs (lncRNAs), as novel genetic factors, on BC risk, survival, clinical and pathological features. Recent studies also investigated the roles of metformin treatment as the firstline treatment for type 2 diabetes (T2D) played in lncRNAs expression/regulation or BC incidence, outcome, mortality and survival, separately. This comprehensive study aimed to review lncRNAs associated with BC features and identify metformin-regulated lncRNAs and their mechanisms of action on BC or other types of cancers. Finally, metformin affects BC by regulating five BC-associated lncRNAs including GAS5, HOTAIR, MALAT1, and H19, by several molecular mechanisms have been described in this review. In addition, metformin action on other types of cancers by regulating ten lncRNAs including AC006160.1, Loc100506691, lncRNA-AF085935, SNHG7, HULC, UCA1, H19, MALAT1, AFAP1-AS1, AC026904.1 is described.

Coding roles of long non-coding RNAs in breast cancer: Emerging molecular diagnostic biomarkers and potential therapeutic targets with special reference to chemotherapy resistance

Dysregulation of epigenetic mechanisms have been depicted in several pathological consequence such as cancer. Different modes of epigenetic regulation (DNA methylation (hypomethylation or hypermethylation of promotor), histone modifications, abnormal expression of microRNAs (miRNAs), long non-coding RNAs, and small nucleolar RNAs), are discovered. Particularly, lncRNAs are known to exert pivot roles in different types of cancer including breast cancer. LncRNAs with oncogenic and tumour suppressive potential are reported. Differentially expressed lncRNAs contribute a remarkable role in the development of primary and acquired resistance for radiotherapy, endocrine therapy, immunotherapy, and targeted therapy. A wide range of molecular subtype specific lncRNAs have been assessed in breast cancer research. A number of studies have also shown that lncRNAs may be clinically used as non-invasive diagnostic biomarkers for early detection of breast cancer. Such molecular biomarkers have also been found in cancer stem cells of breast tumours. The objectives of the present review are to summarize the important roles of oncogenic and tumour suppressive lncRNAs for the early diagnosis of breast cancer, metastatic potential, and chemotherapy resistance across the molecular subtypes.

NOX4 has the potential to be a biomarker associated with colon cancer ferroptosis and immune infiltration based on bioinformatics analysis

Background

Colon cancer (CC) is a common tumor, but its pathogenesis is still not well understood. Competitive endogenous RNA (ceRNA) theory, ferroptosis and tumor immune infiltration may be the mechanisms of the development of cancer. The purpose of the study is to seek genes connected with both immunity and ferroptosis, and provide important molecular basis for early noninvasive diagnosis and immunotherapy of CC.

Methods

We extracted messenger RNA (mRNA), microRNA (miRNA), and long noncoding RNA (lncRNA) data of CC from The Cancer Genome Atlas database (TCGA), identified the differentially expressed mRNA (DEmRNA), miRNA (DEmiRNA) and lncRNA (DElncRNA), then constructed a ceRNA network. Venn overlap analysis was used to identify genes associated with immunity and ferroptosis in ceRNA network. The expression and prognosis of target genes were analyzed via Gene Expression Profiling Interactive Analysis (GEPIA) and PrognoScan database, and we analysed the related functions and signaling pathways of target genes by enrichment analysis. The correlation between target genes and tumor immune infiltrating was explored by CIBERSORT and spearman correlation analysis. Finally, the expression of target genes was detected via quantitative reverse transcription-PCR (qRT-PCR) in CC and normal colon tissues.

Results

Results showed that there were 4 DElncRNA, 4 DEmiRNA and 126 DEmRNA in ceRNA network. NADPH oxidase 4 protein (NOX4) was a DEmRNA associated with immunity and ferroptosis in ceRNA network. NOX4 was highly expressed in CC and connected with unfavourable prognosis. NOX4 was obviously enriched in pathways connected with carcinogenesis and significantly correlated with six kinds of immune cells. Immune checkpoints and NOX4 spearman correlation analysis showed that the expression of NOX4 was positively related to programmed cell death protein 1 (PD-1)-PDCD1, programmed cell death-Ligand 1 (PD-L1)-CD274 and cytotoxic T-lymphocyte-associated protein 4 (CTLA4).

Conclusions

To conclude, our study suggests that NOX4 is associated with both ferroptosis and tumor immunity, and might be a biomarker associated with the carcinogenesis, prognosis of CC and a potential target of CC immunotherapy.

Advances in Biomarkers and Endogenous Regulation of Breast Cancer Stem Cells

Breast cancer is one of the most common cancers. Even if breast cancer patients initially respond to treatment, developed resistance can lead to a poor prognosis. Cancer stem cells (CSCs) are a group of undifferentiated cells with self-renewal and multipotent differentiation characteristics. Existing evidence has shown that CSCs are one of the determinants that contribute to the heterogeneity of primary tumors. The emergence of CSCs causes tumor recurrence, metastasis, and therapeutic resistance. Previous studies indicated that different stemness-associated surface markers can identify other breast cancer stem cell (BCSC) subpopulations. Deciphering the critical signaling networks that are involved in the induction and maintenance of stemness is essential to develop novel BCSC-targeting strategies. In this review, we reviewed the biomarkers of BCSCs, critical regulators of BCSCs, and the signaling networks that regulate the stemness of BCSCs.

Regulation of the Cancer Stem Phenotype by Long Non-Coding RNAs

Cancer stem cells are a cell population within malignant tumors that are characterized by the ability to self-renew, the presence of specific molecules that define their identity, the ability to form malignant tumors in vivo, resistance to drugs, and the ability to invade and migrate to other regions of the body. These characteristics are regulated by various molecules, such as lncRNAs, which are transcripts that generally do not code for proteins but regulate multiple biological processes through various mechanisms of action. LncRNAs, such as HOTAIR, H19, LncTCF7, LUCAT1, MALAT1, LINC00511, and FMR1-AS1, have been described as key regulators of stemness in cancer, allowing cancer cells to acquire this phenotype. It has been proposed that cancer stem cells are clinically responsible for the high recurrence rates after treatment and the high frequency of metastasis in malignant tumors, so understanding the mechanisms that regulate the stem phenotype could have an impact on the improvement of cancer treatments.

Functional interplay between long non-coding RNAs and Breast CSCs

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

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

Nanog, as a key cancer stem cell marker in tumor progression

Cancer stem cells (CSCs) are a small population of malignant cells that induce tumor onset and development. CSCs share similar features with normal stem cells in the case of self-renewal and differentiation. They also contribute to chemoresistance and metastasis of cancer cells, leading to therapeutic failure. To identify CSCs, multiple cell surface markers have been characterized, including Nanog, which is found at high levels in different cancers. Recent studies have revealed that Nanog upregulation has a substantial association with the advanced stages and poor prognosis of malignancies, playing a pivotal role through tumorigenesis of multiple human cancers, including leukemia, liver, colorectal, prostate, ovarian, lung, head and neck, brain, pancreatic, gastric and breast cancers. Nanog through different signaling pathways, like JAK/STAT and Wnt/β-catenin pathways, induces stemness, self-renewal, metastasis, invasiveness, and chemoresistance of cancer cells. Some of these signaling pathways are common in various types of cancers, but some have been found in one or two cancers. Therefore, this review aimed to focus on the function of Nanog in multiple cancers based on recent studies surveying the suitable approaches to target Nanog and inhibit CSCs residing in tumors to gain favorable results from cancer treatments.

Identification of Immune-Related lncRNA Pairs and Construction and Validation of a New Prognostic Signature of Colon Cancer

BACKGROUND

More and more evidence has shown that immune-related long noncoding ribonucleic acid (irlncRNAs) is a potential prognostic factor for colon cancer. The relevant gene pair pattern can improve the sensitivity of the prognostic model. Therefore, our present study aimed to identify irlncRNA Pairs and construct and validate a new prognostic signature in colon cancer.

METHODS

We downloaded the expression matrix of mRNA and lncRNA of patients with colon cancer and their clinical information from the public TCGA database. We obtained immune genes from the ImmPort database. Coexpression analysis was performed to identify irlncRNAs. We built an irlncRNA pair matrix by comparing the expression levels of each lncRNA pair in a cycle. Univariate Cox regression analysis, LASSO penalized regression analysis, and multivariate Cox regression analysis were performed to determine the final variables to construct the prognostic risk score model (a new signature). We draw the receiver operating characteristic (ROC) curves of the signature and clinical characteristics and determine the optimal cutoff value by the optimal Akaike Information Criterion (AIC) value. Based on the optimal cutoff value of the ROC curve of the signature, colon cancer patients were divided into the high- and low-risk groups. Then, the signature was evaluated by clinicopathological features, tumor-infiltrating immune cells, checkpoint-related biomarkers, targeted therapy, and chemotherapy.

RESULTS

We identified 8 lncRNA pairs including AC103740.1|LEF1-AS1, LINC02391|AC053503.5, WWC2-AS2|AL355916.2, AC104090.1|NEURL1-AS1, AC099524.1|AL161908.1, AC074011.1|AL078601.2, AL355916.2|LINC01723, and AP003392.4|LINC00598 from 71 differently expressed irlncRNAs. We constructed a prognostic risk score model (a new signature) using these optimal eight irlncRNA pairs. ROC curve analysis revealed that the highest AUC value of the signature was 0.776 at 1 year, with the optimal cutoff value of 1.283. Our present study also showed that the constructed signature could accurately identify adverse survival outcomes, prognostic clinicopathological features, and specify tumor invasion status. The expression of immune checkpoint-related genes and chemical drug sensitivity were related to different risk groups.

CONCLUSION

In our present study, we constructed a new irlncRNA signature of colon cancer based on the irlncRNA pairs instead of the special expression level of lncRNA. We found this signature had not only good prognostic value but also certain clinical value, which might provide a new insight into the treatment and prognosis of colon cancer.

Long non-coding RNA FEZF1-AS1 promotes rectal cancer progression by competitively binding miR-632 with FAM83A

The long non-coding RNA (lncRNA) forebrain embryonic zinc finger protein 1 antisense RNA1 (FEZF1-AS1) was recently identified as an oncogenic gene in several types of tumors. The biological function of FEZF1-AS1 in rectal cancer progression, however, remains unknown. In the present study, we discover that FEZF1-AS1 is significantly upregulated in rectal cancer tissues and cells. Knocking down of FEZF1-AS1 suppresses cell proliferation, migration, and invasion , and tumorigenesis . Furthermore, FEZF1-AS1 functions as a competing endogenous RNA (ceRNA) for miR-632, resulting in the suppression of family with sequence similarity 83, member A (FAM83A). Overall, our findings reveal that FEZF1-AS1/miR-632/FAM83A axis plays an oncogenic role in rectal cancer progression, suggesting that it may be a novel therapeutic target for rectal cancer.

LINC02381 aggravates breast cancer through the miR-1271-5p/FN1 axis to activate PI3K/AKT pathway

Emerging investigations have demonstrated that lncRNAs are key crucial modulators in cancer. In this study, we investigated the role of LINC02381 in breast cancer (BC). Reverse transcriptase quantitative polymerase chain reaction measured the LINC02381 level in BC tissues and cells. Colony formation, EdU staining, wound healing and Transwell experiments examined the impact of LINC02381 depletion on BC cell phenotypes. Relationship among miR-1271-5p, LINC02381, and FN1 was tested through applying RIP, luciferase reporter, and RNA pull-down assays. We found that LINC02381 expression was elevated in BC. Functionally, LINC02381 knockdown hampered BC cell proliferation, migration, and invasion. LINC02381 overexpression accelerated tumor formation in vivo. Mechanistically, LINC02381 acted as a ceRNA to increase FN1 via decoying miR-1271-5p. Additionally, LINC02381 activated PI3K/AKT pathway by upregulating FN1. Rescue assays indicated that FN1 upregulation or PI3K/AKT activation rescued the LINC02381 knockdown-mediated inhibition on malignant phenotypes of BC cells. Overall, LINC02381 exerts carcinogenic effects in BC by the miR-1271-5p/FN1 axis to activate PI3K/AKT pathway.

Molecular and cellular functions of long non-coding RNAs in prostate and breast cancer

Long noncoding RNAs (lncRNAs) are defined as noncoding RNA transcripts with a length greater than 200 nucleotides. Research over the last decade has made great strides in our understanding of lncRNAs, especially in the biology of their role in cancer. In this article, we will briefly discuss the biogenesis and characteristics of lncRNAs, then review their molecular and cellular functions in cancer by using prostate and breast cancer as examples. LncRNAs are abundant, diverse, and evolutionarily, less conserved than protein-coding genes. They are often expressed in a tumor and cell-specific manner. As a key epigenetic factor, lncRNAs can use a wide variety of molecular mechanisms to regulate gene expression at each step of the genetic information flow pathway. LncRNAs display widespread effects on cell behavior, tumor growth, and metastasis. They act intracellularly and extracellularly in an autocrine, paracrine and endocrine fashion. Increased understanding of lncRNA's role in cancer has facilitated the development of novel biomarkers for cancer diagnosis, led to greater understanding of cancer prognosis, enabled better prediction of therapeutic responses, and promoted identification of potential targets for cancer therapy.

MicroRNAs regulating SOX2 in cancer progression and therapy response

The proliferation, metastasis and therapy response of tumour cells are tightly regulated by interaction among various signalling networks. The microRNAs (miRNAs) can bind to 3'-UTR of mRNA and down-regulate expression of target gene. The miRNAs target various molecular pathways in regulating biological events such as apoptosis, differentiation, angiogenesis and migration. The aberrant expression of miRNAs occurs in cancers and they have both tumour-suppressor and tumour-promoting functions. On the contrary, SOX proteins are capable of binding to DNA and regulating gene expression. SOX2 is a well-known member of SOX family that its overexpression in different cancers to ensure progression and stemness. The present review focuses on modulatory impact of miRNAs on SOX2 in affecting growth, migration and therapy response of cancers. The lncRNAs and circRNAs can function as upstream mediators of miRNA/SOX2 axis in cancers. In addition, NF-κB, TNF-α and SOX17 are among other molecular pathways regulating miRNA/SOX2 axis in cancer. Noteworthy, anti-cancer compounds including bufalin and ovatodiolide are suggested to regulate miRNA/SOX2 axis in cancers. The translation of current findings to clinical course can pave the way to effective treatment of cancer patients and improve their prognosis.

lncRNA FEZF1-AS1 regulates biological behaviors of cervical cancer by targeting miRNA-1254

AIM

The purpose of this research was to evaluate lncRNA FEZF1-AS1 in cervical cancer development and clinical significance.

MATERIALS AND METHODS

Collecting cervical cancer tissues, measuring FEZF1-AS1 expression, and analysis correlation between FEZF1-AS1 and prognosis. In cell vitro study, using MTT assay to measure cell proliferation, evaluating cell apoptosis by flow cytometry, measuring cell invasion and migration by Transwell and wound healing assay; lncRNA FEZF1-AS1 and miR-1254 gene expressions were evaluated by RT-qPCR assay; relative protein (Smurf1, E-cadherin, Vimentin, N-cadherin, AKT, p-AKT, c-Myc, and ZEB1) expressions were measured by Western blot assay. The correlation among FEZF1-AS1, miR-1254, and Smurf1 were analysis by dual luciferase reporter gene assay.

RESULTS

By clinical analysis, lncRNA FEZF1-AS1 was high expression in cervical cancer tissues and high expression was closely correlated with poor prognosis in cervical cancer patients. In vitro study, the SiHa and HeLa cell biologically including cell proliferation, migration, and invasion of si-FEZF1-AS1 group which knockdown lncRNA FEZF1-AS1 were significantly depressed (p < .001, respectively). However, with miR-1254 expression inhibiting, the cell biological activities were significantly increased in si-FEZF1-AS1+miRNA inhibitor groups (p < .001, respectively).

CONCLUSION

lncRNA FEZF1-AS1 might be an oncological role in cervical cancer; lncRNA FEZF1-AS1 knockdown had antitumor effects with miR-1254 activating in cervical cancer by in vitro study.

Epigenetic Regulation of Breast Cancer Stem Cells Contributing to Carcinogenesis and Therapeutic Implications

Globally, breast cancer has remained the most commonly diagnosed cancer and the leading cause of cancer death among women. Breast cancer is a highly heterogeneous and phenotypically diverse group of diseases, which require different selection of treatments. Breast cancer stem cells (BCSCs), a small subset of cancer cells with stem cell-like properties, play essential roles in breast cancer progression, recurrence, metastasis, chemoresistance and treatments. Epigenetics is defined as inheritable changes in gene expression without alteration in DNA sequence. Epigenetic regulation includes DNA methylation and demethylation, as well as histone modifications. Aberrant epigenetic regulation results in carcinogenesis. In this review, the mechanism of epigenetic regulation involved in carcinogenesis, therapeutic resistance and metastasis of BCSCs will be discussed, and finally, the therapies targeting these biomarkers will be presented.

LINC00115 promotes stemness and inhibits apoptosis of ovarian cancer stem cells by upregulating SOX9 and inhibiting the Wnt/β-catenin pathway through competitively binding to microRNA-30a

OBJECTIVE

Long non-coding RNAs (lncRNAs) and microRNAs (miRs) are differentially expressed in ovarian cancer (OC) cells and influence OC progression. This study intended to explore the underlying roles of LINC00115 and miR-30a in OC.

METHODS

Gene Expression Omnibus database was used to find OC microarray datasets and bioinformatics analysis predicted the potential molecular mechanism of OC. OC stem cells (OCSCs) surface marker was isolated from human OC cell line and identified. CD133+ OCSCs were transfected with LINC00115, miR-30a and SOX9 alone or together to detect sphere-forming ability and apoptosis of OCSCs. Caspase-3 activity and DNA damage in cell supernatant were detected. The levels of CD44, NANOG, POU5F1, LINC00115, CD133, miR-30a and SOX9 were measured. Then sh-LNC00115-treated OCSCs were added with Wnt/β-catenin activator SKL2001 to observe the changes of cell stemness and activity. Finally, animal models were established to evaluate the effect of LINC00115 on OCSC in vivo.

RESULTS

LINC00115 and SOX9 were highly expressed in OC, while miR-30a was lowly expressed. After silencing LINC00115 or overexpressing miR-30a, the sphere-forming rate of CD133+ OCSC and levels of CD133, CD44, NANOG and POU5F1 decreased, while apoptotic rate, Caspase-3 activity and histone-related DNA damage increased. SOX9 reversed these trends. Additionally, LINC00115 could bind to miR-30a and miR-30a could target SOX9. SKL2001 partially reversed cell stemness and activity in sh-LNC00115-treated OCSCs. Finally, silencing LINC00115 could inhibit OCSCs growth in vivo.

CONCLUSION

LINC00115 promoted stemness and inhibited apoptosis of OCSCs by upregulating SOX9 and in activating the Wnt/β-catenin pathway through competitively binding to miR-30a.

The interplay between m6A modification and non-coding RNA in cancer stemness modulation: mechanisms, signaling pathways, and clinical implications

Cancer stemness, mainly consisting of chemo-resistance, radio-resistance, tumorigenesis, metastasis, tumor self-renewal, cancer metabolism reprogramming, and tumor immuno-microenvironment remodeling, play crucial roles in the cancer progression process and has become the hotspot of cancer research field in recent years. Nowadays, the exact molecular mechanisms of cancer stemness have not been fully understood. Extensive studies have recently implicated that non-coding RNA (ncRNA) plays vital roles in modulating cancer stemness. Notably, N6-methyladenosine (m6A) modification is of crucial importance for RNAs to exert their biological functions, including RNA splicing, stability, translation, degradation, and export. Emerging evidence has revealed that m6A modification can govern the expressions and functions of ncRNAs, consequently controlling cancer stemness properties. However, the interaction mechanisms between ncRNAs and m6A modification in cancer stemness modulation are rarely investigated. In this review, we elucidate the recent findings on the relationships of m6A modification, ncRNAs, and cancer stemness. We also focus on some key signaling pathways such as Wnt/β-catenin signaling, MAPK signaling, Hippo signaling, and JAK/STAT3 signaling to illustrate the underlying interplay mechanisms between m6A modification and ncRNAs in cancer stemness. In particular, we briefly highlight the clinical potential of ncRNAs and m6A modifiers as promising biomarkers and therapeutic targets for indicating cancer stemness properties and improving the diagnostic precision for a wide variety of cancers.

miR-30a/SOX4 Double Negative Feedback Loop is modulated by Disulfiram and regulates EMT and Stem Cell-like properties in Breast Cancer

Background: Both epithelial-to-mesenchymal transition (EMT) and cancer stem cells play important roles in development and progression of breast cancer. MicroRNA (miR)-30 family members have been reported to be associated with the regulation of EMT and stem cell phenotypes, however, the underlying molecular mechanisms are not well understood.

Methods: miR-30a stable transfectants of breast cancer cell lines were created using a lentiviral system. Bioinformatics analysis was performed to explore miR-30a target genes and SOX4 was selected and identified by dual luciferase reporter assay. The effects of miR-30a and target gene SOX4 on EMT and CSC phenotypes in breast cancer were explored in vitro and in vivo.

Results: Overexpression of miR-30a in breast cancer cells inhibited EMT and CSC phenotypes by targeting SOX4. Luciferase reporter assay confirmed that miR-30a directly targeted 3'UTR of SOX4, and formed a double-negative feedback loop with SOX4. Functional experiments demonstrated that knockdown of SOX4 suppressed EMT and CSC phenotypes of breast cancer cells through TGF-β/SMAD pathway, which was consistent with the inhibitory effects by overexpression of miR-30a. Additionally, we found disulfiram can upregulate miR-30a expression, and high miR-30a expression was associated with a good prognosis in breast cancer patients through TCGA database.

Conclusion: Our findings suggest a novel double-negative loop between miR-30a and SOX4 mediated regulation of EMT and CSC features in breast cancer through TGF-β/SMAD pathway, highlighting a novel therapeutic target for breast cancer.

Novel molecular regulators of breast cancer stem cell plasticity and heterogeneity

Tumors consist of heterogeneous cell populations, and tumor heterogeneity plays key roles in regulating tumorigenesis, metastasis, recurrence and resistance to anti-tumor therapies. More and more studies suggest that cancer stem cells (CSCs) promote tumorigenesis, metastasis, recurrence and drug resistance as well as are the major source for heterogeneity of cancer cells. CD24^-CD44⁺ and ALDH⁺ are the most common markers for breast cancer stem cells (BCSCs). Previous studies showed that different BCSC markers label different BCSC populations, indicating the heterogeneity of BCSCs. Therefore, defining the regulation mechanisms of heterogeneous BCSCs is essential for precisely targeting BCSCs and treating breast cancer. In this review, we summarized the novel regulators existed in BCSCs and their niches for BCSC heterogeneity which has been discovered in recent years, and discussed their regulation mechanisms and the latest corresponding cancer treatments, which will extend our understanding on BCSC heterogeneity and plasticity, and provide better prognosis prediction and more efficient novel therapeutic strategies for breast cancer.

Nanog maintains stemness of Lkb1-deficient lung adenocarcinoma and prevents gastric differentiation

Growing evidence supports that LKB1-deficient KRAS-driven lung tumors represent a unique therapeutic challenge, displaying strong cancer plasticity that promotes lineage conversion and drug resistance. Here we find that murine lung tumors from the KrasLSL-G12D/+ ; Lkb1flox/flox (KL) model show strong plasticity, which associates with up-regulation of stem cell pluripotency genes such as Nanog. Deletion of Nanog in KL model initiates a gastric differentiation program and promotes mucinous lung tumor growth. We find that NANOG is not expressed at a meaningful level in human lung adenocarcinoma (ADC), as well as in human lung invasive mucinous adenocarcinoma (IMA). Gastric differentiation involves activation of Notch signaling, and perturbation of Notch pathway by the γ-secretase inhibitor LY-411575 remarkably impairs mucinous tumor formation. In contrast to non-mucinous tumors, mucinous tumors are resistant to phenformin treatment. Such therapeutic resistance could be overcome through combined treatments with LY-411575 and phenformin. Overall, we uncover a previously unappreciated plasticity of LKB1-deficient tumors and identify the Nanog-Notch axis in regulating gastric differentiation, which holds important therapeutic implication for the treatment of mucinous lung cancer.

LncRNAs and microRNAs as Essential Regulators of Stemness in Breast Cancer Stem Cells

Breast cancer is an aggressive disease with a high incidence in women worldwide. Two decades ago, a controversial hypothesis was proposed that cancer arises from a subpopulation of "tumor initiating cells" or "cancer stem cells-like" (CSC). Today, CSC are defined as small subset of somatic cancer cells within a tumor with self-renewal properties driven by the aberrant expression of genes involved in the maintenance of a stemness-like phenotype. The understanding of the underlying cellular and molecular mechanisms involved in the maintenance of CSC subpopulation are fundamental in the development and persistence of breast cancer. Nowadays, the hypothesis suggests that genetic and epigenetic alterations give rise to breast cancer stem cells (bCSC), which are responsible for self-renewal, tumor growth, chemoresistance, poor prognosis and low survival in patients. However, the prominence of bCSC, as well as the molecular mechanisms that regulates and promotes the malignant phenotypes, are still poorly understood. The role of non-coding RNAs (ncRNAs), such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) acting as oncogenes or tumor suppressor genes has been recently highlighted by a plethora of studies in breast cancer. These ncRNAs positively or negatively impact on different signaling pathways that govern the cancer hallmarks associated with bCSC, making them attractive targets for therapy. In this review, we present a current summary of the studies on the pivotal roles of lncRNAs and microRNAs in the regulation of genes associated to stemness of bCSC.

circRNA hsa_circ_0018414 inhibits the progression of LUAD by sponging miR-6807-3p and upregulating DKK1

Lung adenocarcinoma (LUAD) is a subtype of lung cancer with a high incidence and mortality all over the world. In recent years, circular RNAs (circRNAs) have been verified to be a novel subtype of noncoding RNAs that exert vital functions in various cancers. Our research was designed to investigate the role of circ_0018414 in LUAD. We first observed that circ_0018414 was downregulated in LUAD tissues and cells. Also, low expression of circ_0018414 predicted unfavorable prognosis of LUAD patients. Then, upregulation of circ_0018414 repressed cell proliferation and stemness, while promoting cell apoptosis, in LUAD. Moreover, circ_0018414 overexpression enhanced the expression of its host gene, dickkopf WNT signaling pathway inhibitor 1 (DKK1), therefore inactivating the Wnt/β-catenin pathway. Additionally, circ_0018414 could sponge miR-6807-3p to protect DKK1 mRNA from miR-6807-3p-induced silencing, leading to DKK1 upregulation in LUAD cells. Finally, rescue assays proved that circ_0018414 inhibited the progression of LUAD via the miR-6807-3p/DKK1 axis-inactivated Wnt/β-catenin pathway. The findings in our work indicated circ_0018414 as a tumor inhibitor in LUAD, which might provide a new perspective for LUAD treatment.

Long non-coding RNA LSINCT5 inactivates Wnt/β-catenin pathway to regulate MCF-7 cell proliferation and motility through targeting the miR-30a

Background

Breast cancer (BC) is the most common malignant tumor among women. Earlier studies showed that long stress-induced non-coding transcript 5 (LSINCT5) was implicated in BC. However, the potential mechanisms of LSINCT5 in BC is still elusive.

Methods

Relative expression of LSINCT5 in BC tissues and cells were quantified by quantitative real-time reverse transcription PCR (qRT-PCR). shRNA was employed to specifically knockdown endogenous LSINCT5 in BC cells. Cell growth and invasion activity of BC cells was assessed by colony formation and transwell migration assay, respectively. The association between LSINCT5 and miR-30a was conducted by luciferase reporter assay. Subcutaneous injection of sh-LSINCT5 transfected MCF-7 cells into the ventral regions of mice to form tumors. Mice were divided into three groups (n=10): control group, sh-NC group, sh-LSINCT5 group (sh-NC or sh-LSINCT5 transfected MCF-7 cells injected into mice). Tumor weight was checked after 30 days post-injection.

Results

LSINCT5 was significantly up-regulated in BC tissues and cells. LSINCT5 knockdown suppressed proliferation, invasion, and epithelial-mesenchymal transition (EMT) in vitro and in vivo. LSINCT5 acted as a sponge molecule and targeted miR-30a in BC cells. Further mechanistic study exhibited that overexpression of LSINCT5 promoted the expression of Wnt/β-catenin-related proteins (β-catenin, TCF4, and c-Myc). In vivo, xenograft nude mice experiment indicated sh-LSINCT5 inhibited tumor growth and motility by targeting miR-30a through modulating Wnt/β-catenin pathway.

Conclusions

The present results uncovered that LSINCT5 knockdown suppressed BC growth and metastasis via the miR-30a/Wnt/β-catenin axis, and it served as a potential therapeutic target for early diagnosis and treatment of BC patients..

Long non‑coding RNA FEZF1‑AS1 facilitates non‑small cell lung cancer progression via the ITGA11/miR‑516b‑5p axis

Long non-coding RNAs (lncRNAs) have emerged as key players in the development and progression of cancer. FEZ family zinc finger 1 antisense RNA 1 (FEZF1-AS1) is a novel lncRNA that is involved in the development of cancer and acts as a potential biomarker for cancer. However, the clinical significance and molecular mechanism of FEZF1-AS1 in non-small cell lung cancer (NSCLC) remains uncertain. In the present study, FEZF1-AS1 was selected using Arraystar Human lncRNA microarray and was identified to be upregulated in NSCLC tissues and negatively associated with the overall survival of patients with NSCLC. Loss-of-function assays revealed that FEZF1-AS1 inhibition decreased cell proliferation and migration, and arrested cells at the G₂/M cell cycle phase. Mechanistically, FEZF1-AS1 expression was influenced by N6-methyladenosine (m⁶A) modification. Since FEZF1-AS1 was mainly located in the cytoplasmic fraction of NSCLC cells, it was hypothesized that it may be involved in competing endogenous RNA regulatory network to impact the prognosis of NSCLC. Via integrating Arraystar Human mRNA microarray data and miRNA bioinformatics analysis, it was revealed that ITGA11 expression was decreased with loss of FEZF1-AS1 and increased with gain of FEZF1-AS1 expression, and microRNA (miR)-516b-5p inhibited the expression levels of both FEZF1-AS and ITGA11. RNA-binding protein immunoprecipitation and RNA pulldown assays further demonstrated that FEZF1-AS1 could bind to miR-516b-5p and that ITGA11 was a direct target of miR-516b-5p by luciferase reporter assay. Overall, the present findings demonstrated that FEZF1-AS1 was upregulated and acted as an oncogene in NSCLC by regulating the ITGA11/miR-516b-5p axis, suggesting that FEZF1-AS1 may be a potential prognostic biomarker and therapeutic target for NSCLC.

The oncogenic potential of NANOG: An important cancer induction mediator

Cancer stem cells (CSCs) are a unique population in the tumor, but they only comprise 2%-5% of the tumor bulk. Although CSCs share several features with embryonic stem cells, CSCs can give rise to the tumor cells. CSCs overexpress embryonic transcription factor NANOG, which is downregulated in differentiated tissues. This transcription factor confers CSC's stemness, unlimited self-renewal, metastasis, invasiveness, angiogenesis, and drug-resistance with the assistance of WNT, OCT4, SOX2, Hedgehog, BMI-1, and other complexes. NANOG facilitates CSCs development via multiple pathways, like angiogenesis and lessening E-cadherin expression levels, which paves the road for metastasis. Moreover, NANOG represses apoptosis and leads to drug-resistance. This review aims to highlight the pivotal role of NANOG and the pertained pathways in CSCs. Also, this current study intends to demonstrate that targeting NANOG can dimmish the CSCs, sensitize the tumor to chemotherapy, and eradicate the cancer cells.

lncRNA FEZF1‑AS1 promotes migration, invasion and epithelial‑mesenchymal transition of retinoblastoma cells by targeting miR‑1236‑3p

Long non-coding RNAs (lncRNAs) and microRNAs (miRs) have been reported to regulate disease progression in numerous types of disease, including retinoblastoma (Rb). Therefore, the present study aimed to investigate the effects of the lncRNA FEZ family zinc finger 1 antisense RNA 1 (FEZF1-AS1) on Rb and to determine its possible mechanism of action. Reverse transcription-quantitative PCR and western blot analysis were conducted to detect the gene or protein expression. Cell Counting Kit-8, wound healing and transwell invasion assays were performed to estimate the capabilities of cell viability, invasion and migration. The potential association between FEZF1-AS1 and miR-1236-3p in Y79 cells was measured via dual-luciferase reporter assay. The results of the present study revealed that the levels of FEZF1-AS1 were significantly upregulated in different Rb cell lines, with the most prominent upregulation observed in Y79 cells. In addition, the cell viability, invasive and migratory abilities, and the ability to undergo epithelial-mesenchymal transition (EMT), were significantly inhibited following the transfection of short hairpin RNA (shRNA)-FEZF1-AS1 into Y79 cells. Further experimental validation confirmed that miR-1236-3p may be a direct target of FEZF1-AS1. Notably, the miR-1236-3p inhibitor was discovered to reverse the inhibitory effects of shRNA-FEZF1-AS1 on cell viability, invasion, migration and EMT. In conclusion, the findings of the present study suggested that lncRNA-FEZF1-AS1 may promote the viability, migration, invasion and EMT of Rb cells by modulating miR-1236-3p.

Identification and validation of stemness-related lncRNA prognostic signature for breast cancer

BACKGROUND

Long noncoding RNAs (lncRNAs) are emerging as crucial contributors to the development of breast cancer and are involved in the stemness regulation of breast cancer stem cells (BCSCs). LncRNAs are closely associated with the prognosis of breast cancer patients. It is critical to identify BCSC-related lncRNAs with prognostic value in breast cancer.

METHODS

A co-expression network of BCSC-related mRNAs-lncRNAs from The Cancer Genome Atlas (TCGA) was constructed. Univariate and multivariate Cox proportional hazards analyses were used to identify a stemness risk model with prognostic value. Kaplan-Meier analysis, univariate and multivariate Cox regression analyses and receiver operating characteristic (ROC) curve analysis were performed to validate the risk model. Principal component analysis (PCA) and Gene Set Enrichment Analysis (GSEA) functional annotation were conducted to analyze the risk model.

RESULTS

In this study, BCSC-related lncRNAs in breast cancer were identified. We evaluated the prognostic value of these BCSC-related lncRNAs and eventually obtained a prognostic risk model consisting of 12 BCSC-related lncRNAs (Z68871.1, LINC00578, AC097639.1, AP003119.3, AP001207.3, LINC00668, AL122010.1, AC245297.3, LINC01871, AP000851.2, AC022509.2 and SEMA3B-AS1). The risk model was further verified as a novel independent prognostic factor for breast cancer patients based on the calculated risk score. Moreover, based on the risk model, the low- risk and high-risk groups displayed different stemness statuses.

CONCLUSIONS

These findings suggested that the 12 BCSC-related lncRNA signature might be a promising prognostic factor for breast cancer and can promote the management of BCSC-related therapy in clinical practice.

Signaling pathways and microRNAs, the orchestrators of NANOG activity during cancer induction

Cancer stem cells (CSCs) are a small part of cancer cells inside the tumor that have similar characteristics to normal stem cells. CSCs stimulate tumor initiation and progression in a variety of cancers. Several transcription factors such as NANOG, SOX2, and OCT4 maintain the characteristics of CSCs and their upregulation is seen in many malignancies resulting in increased metastasis, invasion, and recurrence. Among these factors, NANOG plays an important role in regulating the self-renewal and pluripotency of CSCs and the clinical significance of NANOG has been suggested as a marker of CSCs in many cancers. The up and down-regulation of NANOG is associated with several important signaling pathways, including JAK/STAT, Wnt/β-catenin, Notch, TGF-β, Hedgehog, and several microRNAs (miRNAs). In this review, we will investigate the function of NANOG in CSCs and the molecular mechanism of its regulation by signaling pathways and miRNAs. We will also investigate targeting NANOG with different techniques, which is a promising treatment strategy for cancer treatment.

Noncoding RNAs: the shot callers in tumor immune escape

Immunotherapy, designed to exploit the functions of the host immune system against tumors, has shown considerable potential against several malignancies. However, the utility of immunotherapy is heavily limited due to the low response rate and various side effects in the clinical setting. Immune escape of tumor cells may be a critical reason for such low response rates. Noncoding RNAs (ncRNAs) have been identified as key regulatory factors in tumors and the immune system. Consequently, ncRNAs show promise as targets to improve the efficacy of immunotherapy in tumors. However, the relationship between ncRNAs and tumor immune escape (TIE) has not yet been comprehensively summarized. In this review, we provide a detailed account of the current knowledge on ncRNAs associated with TIE and their potential roles in tumor growth and survival mechanisms. This review bridges the gap between ncRNAs and TIE and broadens our understanding of their relationship, providing new insights and strategies to improve immunotherapy response rates by specifically targeting the ncRNAs involved in TIE.

ZGRF1 Is Associated with Poor Prognosis in Triple-Negative Breast Cancer and Promotes Cancer Stemness Based on Bioinformatics

Background

Recently, long non-coding RNAs (lncRNAs) are important populations of non-coding RNAs with defined key roles in normal breast development as well as breast tumorigenesis. Triple-negative breast cancer (TNBC) is a particular breast cancer subtype with poor prognosis because of highly invasive and no specific drug treatment yet. Breast cancer stems cells (BCSCs) cause a high risk of invasion, metastasis and drug resistance for breast cancer patients.

Methods

Two microarrays of BCSCs and no-BCSCs were isolated from mammosphere-3D-cultured MCF-7 cells, differentially expressed lncRNAs (DELs) were screened out by Gene Expression Omnibus (GEO). Gene ontology enrichment analysis and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were also performed to analyze DELs features. Using the STRING database to analyze DELs interaction network module to further screen the hub lncRNAs related to tumor stemness and make functional annotations. The expressions of hub DELs were validated using data from The Cancer Genome Atlas database. In addition, the expression analysis and survival analysis were conducted using GEO was utilized to analyze DELs in TNBC using GEPIA database.

Results

A total of 143 aberrantly expressed lncRNAs in BCSCs were identified, and 25 lncRNAs were downregulated and 118 lncRNAs were upregulated compared to non-BCSCs. Up- and downregulated top 3 lncRNAs were selected and verified by RT-PCR. Notably, GO enrichment analysis and KEGG pathway analysis indicated that RNA transport, spliceosome, oxidative phosphorylation, NOD-like receptor signaling pathway, PI3K-Akt signaling pathway, and metabolic pathways may serve important roles in BCSCs. Additionally, the function loss assay indicated that ZGRF1 positively upregulated phenotype and biological functions of BCSCs in vitro. Collectively, our work establishes the lncRNAs signature in BCSCs and these findings assess us with evidence to explore further functionalities of lncRNAs in BCSCs and provide a novel therapeutic strategy for breast cancer.

Conclusion

Our work establishes the lncRNAs signature in BCSCs and these findings assess us with evidence to explore further functionalities of lncRNAs in BCSCs and provide a novel therapeutic strategy for breast cancer. ZGRF1 expression is upregulated in TNBC patients and has a poor prognosis, which can be promising biomarkers.

[Progress in Role of FEZF1-AS1 in Non-small Cell Lung Cancer]

Nowadays, accumulating evidence indicates that long non-coding RNA (lncRNA) play vital roles in tumorigenesis. As a newly discovered lncRNA, FEZ family zinc finger 1-antisense RNA 1 (FEZF1-AS1) is markedly upregulated in various malignant tumors including non-small cell lung cancer (NSCLC). Aberrant expression of FEZF1-AS1 is related to clinical characteristics of patients with NSCLC and suggests poor prognosis. Moreover, FEZF1-AS1 can regulate numerous biological processes, such as cell proliferation, migration and invasion through different mechanisms. In this article, we systematically summarize the recent research progress of FEZF1-AS1 in NSCLC, which might be a novel target for clinical therapy.

The Missing Lnc: The Potential of Targeting Triple-Negative Breast Cancer and Cancer Stem Cells by Inhibiting Long Non-Coding RNAs

Treatment decisions for breast cancer are based on staging and hormone receptor expression and include chemotherapies and endocrine therapy. While effective in many cases, some breast cancers are resistant to therapy, metastasize and recur, leading to eventual death. Higher percentages of tumor-initiating cancer stem cells (CSCs) may contribute to the increased aggressiveness, chemoresistance, and worse outcomes among breast cancer. This may be particularly true in triple-negative breast cancers (TNBCs) which have higher percentages of CSCs and are associated with worse outcomes. In recent years, increasing numbers of long non-coding RNAs (lncRNAs) have been identified as playing an important role in breast cancer progression and some of these have been specifically associated within the CSC populations of breast cancers. LncRNAs are non-protein-coding transcripts greater than 200 nucleotides which can have critical functions in gene expression regulation. The preclinical evidence regarding lncRNA antagonists for the treatment of cancer is promising and therefore, presents a potential novel approach for treating breast cancer and targeting therapy-resistant CSCs within these tumors. Herein, we summarize the lncRNAs that have been identified as functionally relevant in breast CSCs. Furthermore, our review of the literature and analysis of patient datasets has revealed that many of these breast CSC-associated lncRNAs are also enriched in TNBC. Together, this suggests that these lncRNAs may be playing a particularly important role in TNBC. Thus, certain breast cancer-promoting/CSC-associated lncRNAs could be targeted in the treatment of TNBCs and the CSCs within these tumors should be susceptible to anti-lncRNA therapy.

LncRNA FEZF1-AS1 Sponges miR-34a to Upregulate Notch-1 in Glioblastoma

Introduction

LncRNA FEZF1-AS1 has been reported to be an oncogene in many types of cancer, while its role in glioblastoma (GBM) is unknown. This study aimed to investigate the potential involvement of FEZF1-AS1 in GBM.

Methods

FEZF1-AS1 expression in paired GBM and non-tumor tissues from GBM patients was determined by RT-qPCR. A 2-year follow-up was performed to analyze the prognostic value of FEZF1-AS1 for GBM. Cell transfections were performed to analyze the interactions between FEZF1-AS1, miR-34a and Notch-1. Transwell assay was performed to analyze the role of FEZF1-AS1, miR-34a and Notch-1 in regulating GBM cell invasion and migration.

Results

In this study, analysis of TCGA dataset revealed the upregulation of FEZF1-AS1 in GBM, and the overexpression of FEZF1-AS1 in GBM was further confirmed using GBM tissues from GBM patients included in this study. High levels of FEZF1-AS1 were correlated with poor survival. FEZF1-AS1 was predicted to form base pairing with miR-34a. However, overexpression of FEZF1-AS1 and miR-34a failed to affect the expression of each other. However, upregulation of Notch-1, a target of miR-34a, was observed after FEZF1-AS1 in GBM cells. Moreover, increased invasion and migration rates of GBM cells were observed after FEZF1-AS1 and Notch-1 overexpression. MiR-34a played an opposite role and reduced the effects of FEZF1-AS1 and Notch-1 overexpression.

Conclusion

FEZF1-AS1 may sponge miR-34a to upregulate Notch-1 in GBM, thereby promoting cancer cell invasion and migration.

Post-transcriptional regulations of cancer stem cell homeostasis

PURPOSE OF REVIEW

Although extensively studied for over a decade, gene expression programs established at the epigenetic and/or transcriptional levels do not fully characterize cancer stem cells (CSC). This review will highlight the latest advances regarding the functional relevance of different key post-transcriptional regulations and how they are coordinated to control CSC homeostasis.

RECENT FINDINGS

In the past 2 years, several groups have identified master post-transcriptional regulators of CSC genetic programs, including RNA modifications, RNA-binding proteins, microRNAs and long noncoding RNAs. Of particular interest, these studies reveal that different post-transcriptional mechanisms are coordinated to control key signalling pathways and transcription factors to either support or suppress CSC homeostasis.

SUMMARY

Deciphering molecular mechanisms coordinating plasticity, survival and tumourigenic capacities of CSCs in adult and paediatric cancers is essential to design new antitumour therapies. An entire field of research focusing on post-transcriptional gene expression regulation is currently emerging and will significantly improve our understanding of the complexity of the molecular circuitries driving CSC behaviours and of druggable CSC weaknesses.

Long non-coding RNA dysregulation is a frequent event in non-small cell lung carcinoma pathogenesis

Background

Long non-coding RNAs compose an important level of epigenetic regulation in normal physiology and disease. Despite the plethora of publications of lncRNAs in human cancer, the landscape is still unclear.

Methods

Microarray analysis in 44 NSCLC paired specimens was followed by qPCR-based validation in 29 (technical) and 38 (independent) tissue pairs. Cross-validation of the selected targets was achieved in 850 NSCLC tumours from TCGA datasets.

Results

Twelve targets were successfully validated by qPCR (upregulated: FEZF1-AS1, LINC01214, LINC00673, PCAT6, NUTM2A-AS1, LINC01929; downregulated: PCAT19, FENDRR, SVIL-AS1, LANCL1-AS1, ADAMTS9-AS2 and LINC00968). All of them were successfully cross validated in the TCGA datasets. Abnormal DNA methylation was observed in the promoters of FENDRR, FEZF1-AS1 and SVIL-AS1. FEZF1-AS1 and LINC01929 were associated with survival in the TCGA set.

Conclusions

Our study provides through multiple levels of internal and external validation, a comprehensive list of dysregulated lncRNAs in NSCLC. We therefore envisage this dataset to serve as an important source for the lung cancer research community assisting future investigations on the involvement of lncRNAs in the pathogenesis of the disease and providing novel biomarkers for diagnosis, prognosis and therapeutic stratification.

Research progress on the interactions between long non-coding RNAs and microRNAs in human cancer

Numerous types of molecular mechanisms mediate the development of cancer. Non-coding RNAs (ncRNAs) are being increasingly recognized to play important role in mediating the development of diseases, including cancer. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are the two most widely studied ncRNAs. Thus far, lncRNAs are known to have biological roles through a variety of mechanisms, including genetic imprinting, chromatin remodeling, cell cycle control, splicing regulation, mRNA decay and translational regulation, and miRNAs regulate gene expression through the degradation of mRNAs and lncRNAs. Although ncRNAs account for a major proportion of the total RNA, the mechanisms underlying the physiological or pathological processes mediated by various types of ncRNAs, and the specific interaction mechanisms between miRNAs and lncRNAs in various physiological and pathological processes, remain largely unknown. Thus, further research in this field is required. In general, the interaction mechanisms between miRNAs and lncRNAs in human cancer have become important research topics, and the study thereof has led to the recent development of related technologies. By providing examples and descriptions, and performing chart analysis, the present study aimed to review the interaction mechanisms and research approaches for these two types of ncRNAs, as well as their roles in the occurrence and development of cancer. These details have far-reaching significance for the utilization of these molecules in the diagnosis and treatment of cancer.

LncRNA SPRY4-IT1 regulates breast cancer cell stemness through competitively binding miR-6882-3p with TCF7L2

SPRY4-intronic transcript 1 has been found in several kinds of cancers, but the role of SPRY4-IT1 in breast cancer stem cells has not been studied. We investigated whether SPRY4-IT1 is involved in the promotion of breast cancer stem cells (BCSCs). We used qRT-PCR to detect the expression of SPRY4-IT1 in MCF-7 cells and MCF-7 cancer stem cells (MCF-7 CSCs). The effects of SPRY4-IT1 on the proliferation and renewal ability of breast cancer cells were investigated by in vitro and in vivo assays (ie in situ hybridization, colony formation assay, sphere formation assay, flow cytometry assay, western blotting, xenograft model and immunohistochemistry). The mechanism of SPPRY4-IT1 as a ceRNA was studied by a dual-luciferase reporter assay and bioinformatic analysis. In our study, SPRY4-IT1 was up-regulated in MCF-7 CSCs compared with MCF-7 cells, and high SPRY4-IT1 expression was related to reduced breast cancer patient survival. Furthermore, SPRY4-IT1 overexpression promoted breast cancer cell proliferation and stemness in vitro and in vivo. In addition, SPRY4-IT1 knockdown suppressed BCSC renewal ability and stemness maintenance in vivo and in vitro. The dual-luciferase reporter assays indicated that SPRY4-IT1 as a sponge for miR-6882-3p repressed transcription factor 7-like 2 (TCF7L2) expression. Taken together, these findings demonstrated that SPRY4-IT1 promotes proliferation and stemness of breast cancer cells as well as renewal ability and stemness maintenance of BCSCs by increasing the expression of TCF7L2 through targeting miR-6882-3p.

Long Non-Coding RNA: Dual Effects on Breast Cancer Metastasis and Clinical Applications

As a highly heterogeneous malignancy, breast cancer (BC) has become the most significant threat to female health. Distant metastasis and therapy resistance of BC are responsible for most of the cases of mortality and recurrence. Distant metastasis relies on an array of processes, such as cell proliferation, epithelial-to-mesenchymal transition (EMT), mesenchymal-to-epithelial transition (MET), and angiogenesis. Long non-coding RNA (lncRNA) refers to a class of non-coding RNA with a length of over 200 nucleotides. Currently, a rising number of studies have managed to investigate the association between BC and lncRNA. In this study, we summarized how lncRNA has dual effects in BC metastasis by regulating invasion, migration, and distant metastasis of BC cells. We also emphasize that lncRNA has crucial regulatory effects in the stemness and angiogenesis of BC. Clinically, some lncRNAs can regulate chemotherapy sensitivity in BC patients and may function as novel biomarkers to diagnose or predict prognosis for BC patients. The exact impact on clinical relevance deserves further study. This review can be an approach to understanding the dual effects of lncRNAs in BC, thereby linking lncRNAs to quasi-personalized treatment in the future.

Novel and Alternative Targets Against Breast Cancer Stemness to Combat Chemoresistance

Breast cancer stem cells (BCSCs) play a vital role in tumor progression and metastasis. They are heterogeneous and inherently radio- and chemoresistant. They have the ability to self-renew and differentiate into non-BCSCs. These determinants of BCSCs including the plasticity between the mesenchymal and epithelial phenotypes often leads to minimal residual disease (MRD), tumor relapse, and therapy failure. By studying the resistance mechanisms in BCSCs, a combinatorial therapy can be formulated to co-target BCSCs and bulk tumor cells. This review addresses breast cancer stemness and molecular underpinnings of how the cancer stemness can lead to pharmacological resistance. This might occur through rewiring of signaling pathways and modulated expression of various targets that support survival and self-renewal, clonogenicity, and multi-lineage differentiation into heterogeneous bulk tumor cells following chemotherapy. We explore emerging novel and alternative molecular targets against BC stemness and chemoresistance involving survival, drug efflux, metabolism, proliferation, cell migration, invasion, and metastasis. Strategic targeting of such vulnerabilities in BCSCs may overcome the chemoresistance and increase the longevity of the metastatic breast cancer patients.

Silencing of long noncoding RNA SBF2-AS1 inhibits proliferation, migration and invasion and contributes to apoptosis in osteosarcoma cells by upregulating microRNA-30a to suppress FOXA1 expression

Objectives: Long noncoding RNA (lncRNA) SBF2-AS1 was found to be related to some tumors. Nevertheless, the role of SBF2-AS1 in osteosarcoma (OS) is still needed to be elaborated. This study is conducted to examine the expression of lncRNA SBF2-AS1 in OS with the involvement of microRNA-30a (miR-30a) and FOXA1. Methods: OS tissues and its corresponding adjacent normal tissues were obtained for the detection of SBF2-AS1 expression and its relations with clinical phenotypes. OS cells with most significant expression of SBF2-AS1 were selected for subsequent experiments. Moreover, a series of experiments were performed to detect proliferation, invasion, migration, colony formation, cell cycle distribution and apoptosis of OS cells. Furthermore, the binding site between SBF2-AS1 and miR-30a as well as between miR-30a and FOXA1 was verified. Results: SBF2-AS1 was overexpressed in tissues and cells of OS. Additionally, silencing of SBF2-AS1 and miR-30a overexpression inhibited the proliferation, migration and invasion of OS cells and promoted their apoptosis. Moreover, lncRNA SBF2-AS1 regulated miR-30a by serving as a ceRNA, thus promoting FOXA1 expression. Furthermore, interfered SBF2-AS1 or upregulated miR-30a restrained the growth of OS. Conclusion: Our study confirms that silencing of SBF2-AS1 represses proliferation, migration and invasion of OS cells and promotes their apoptosis by binding to miR-30a and inhibiting FOXA1 expression.

miR-638 represses the stem cell characteristics of breast cancer cells by targeting E2F2

OBJECTIVE

The miR-638 acted as a tumor suppressor and E2F transcription factor 2 (E2F2) was a critical regulator in some cancers, while the role of them on stemness of breast cancer stem cells (BCSCs) was rarely detailed. Hence, we focused on exploring the effects of miR-638 and E2F2 on BCSCs stemness.

METHODS

The proportion of CD24 -/CD44 + cells of BCSCs was detected by flow cytometry. The target relationship of miR-638 and E2F2 was explored using luciferase assays. The ability of self-renewal, proliferation, and invasion of BCSCs were determined by Mammosphere forming, Cell Counting Kit-8 (CCK-8), colony formation, and transwell assays. Xenograft tumor was established to detect the influence of miR-638 on tumor growth.

RESULTS

miR-638 was down-regulated, while E2F2 was elevated in breast cancer. The E2F2 level was negatively correlated with miR-638. The BCSCs represented higher proportion of CD24 -/CD44 + cells and levels of sex determining region Y-box 2 (SOX2) and octamer-binding transcription factor 4 (OCT4). The miR-638 was down-regulated and E2F2 was increased in BCSCs. MiR-638 could target to E2F2 and decreased the level of E2F2 in BCSCs cells. Overexpression of miR-638 decreased the proportion of CD24 -/CD44 + cells and the levels of SOX2 and OCT4 by inhibiting E2F2. The overexpression of miR-638 also inhibited the abilities of self-renewal, proliferation, and invasion of BCSCs by inhibiting E2F2. The miR-638 overexpression inhibited the breast tumor growth.

CONCLUSION

MiR-638 represses the characteristics and behaviors of BCSCs by targeting E2F2. MiR-638 may be a potential target for breast cancer therapy.

Long non-coding RNA LUCAT1/miR-5582-3p/TCF7L2 axis regulates breast cancer stemness via Wnt/β-catenin pathway

Background

The mechanism underlying breast cancer stem cell (BCSCs) characteristics remains to be fully elucidated. Accumulating evidence implies that long noncoding RNAs (lncRNAs) play a pivotal role in regulating BCSCs stemness.

Methods

LncRNA LUCAT1 expression was assessed in breast cancer tissues (n = 151 cases) by in situ hybridization. Sphere-formation assay and colony formation assay were used to detect cell self-renewal and proliferation, respectively. RNA immunoprecipitation, RNA pull down and luciferase reporter assays were used to identify LUCAT1 and TCF7L2 as the direct target of miR-5582-3p. The activity of the Wnt/β-catenin pathway was analyzed by TOP/FOP-Flash reporter assays, western blot and immunohistochemistry (IHC).

Results

This study found LUCAT1 expression was related to tumor size (p = 0.015), lymph node metastasis (p = 0.002) and TNM staging (p < 0.001). High LUCAT1 expression indicated a shorter overall survival (p = 0.006) and disease-free survival (p = 0.011). Furthermore, LUCAT1 was more expressed in BCSCs than in breast cancer cells (BCCs) by lncRNA microarray chips. LUCAT1 up-regulation promoted proliferation of BCCs, while LUCAT1 down-regulation inhibited self-renewal of BCSCs. MiR-5582-3p was directly bound to LUCAT1 and TCF7L2 and negatively regulated their expression. LUCAT1 affected Wnt/β-catenin pathway.

Conclusions

LUCAT1 might be a significant biomarker to evaluate prognosis in breast cancer. LUCAT1 increased stem-like properties of BCCs and stemness of BCSCs by competitively binding miR-5582-3p with TCF7L2 and enhancing the Wnt/β-catenin pathway. The LUCAT1/miR-5582-3p/TCF7L2 axis provides insights for regulatory mechanism of stemness, and new strategies for clinical practice.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1315-8) contains supplementary material, which is available to authorized users.