Regulatory and therapeutic implications of competing endogenous RNA network in breast cancer progression and metastasis: A review

Breast cancer (BC) is a global health concern, and development of diagnostic tools and targeted treatments for BC remains challenging. Therapeutic approaches for BC often involve a combination of surgery, radiation therapy, chemotherapy, targeted therapy, and hormone therapy. In recent years, there has been a growing interest in the role of noncoding RNAs (ncRNAs), including long ncRNAs (lncRNAs) and microRNAs (miRNAs), in BC and their therapeutic implications. Various biological processes such as cell proliferation, migration, and apoptosis rely on the activities of these ncRNAs, and their dysregulation has been implicated in BC progression. The regulatory function of the competitive endogenous RNA (ceRNA) network, which comprises lncRNAs, miRNAs, and mRNAs, has been the subject of extensive pathophysiological research. Most lncRNAs serve as molecular sponges for miRNAs and sequester their activities, thereby regulating the expression of target mRNAs and contributing to the promotion or inhibition of BC progression. This review summarizes recent findings on the role of ceRNA networks in BC progression, metastasis, and therapeutic resistance, and highlights the association of ceRNA networks with transcription factors and signaling pathways. Understanding the ceRNA network can lead to the discovery of biomarkers and targeted treatment methods to prevent the spread and metastasis of BC.

Clinical importance of serum miRNA levels in breast cancer patients

There is limited data on the relationship of miRNAs with parameters that may affect surgical management or reflect tumour prognosis. It was aimed to evaluate serum miRNA levels in breast carcinoma cases and reveal the relationship between these levels and prognosis-related factors such as the histological type of the tumour, estrogen receptor, progesterone receptor, Ki-67 index, HER-2neu, E-cadherin, tumour size, CK5/6, CA15.3 levels, number of tumour foci, number of metastatic lymph nodes, and status of receiving neoadjuvant therapy. Thirty-five patients with a histopathologically confirmed breast carcinoma diagnosis in the case group and 35 healthy individuals in the control group were examined. miR-206, miR-17-5p, miR-125a, miR-125b, miR-200a, Let-7a, miR-34a, miR-31, miR-21, miR-155, miR-10b, miR-373, miR-520c, miR-210, miR-145, miR-139-5p, miR-195, miR-99a, miR-497 and miR-205 expression levels in the serum of participants were determined using the Polymerase Chain Reaction method. While serum miR-125b and Let-7a expression levels were significantly higher in breast cancer patients, miR-17-5p, miR-125a, miR-200a, miR-34a, miR-21, miR-99a and miR-497 levels were significantly lower in them. The Let-7a expression level had a statistically significant relationship with breast cancer histological type and HER-2neu parameters, miR-17-5p, miR-125b, Let-7a, miR-34a, miR-21 and miR-99a levels with E-cadherin, miR-34a, miR-99a and miR-497 with CA15.3, miR-125b, miR-200a and miR-34a with the number of metastatic lymph nodes, miR-125a with the number of tumour foci and miR-200a with the status of having the neoadjuvant therapy. Serum miR-17-5p, miR-125a, miR-125b, miR-200a, Let-7a, miR-34a, miR-21, miR-99a and miR-497 expression levels were determined to have predictive and prognostic importance in breast cancer.

Research progress of Claudin-low breast cancer

Claudin-low breast cancer (CLBC) is a subgroup of breast cancer discovered at the molecular level in 2007. Claudin is one of the primary proteins that make up tight junctions, and it plays crucial roles in anti-inflammatory and antitumor responses as well as the maintenance of water and electrolyte balance. Decreased expression of claudin results in the disruption of tight junction structures and the activation of downstream signaling pathways, which can lead to tumor formation. The origin of Claudin-low breast cancer is still in dispute. Claudin-low breast cancer is characterized by low expression of Claudin3, 4, 7, E-cadherin, and HER2 and high expression of Vimentin, Snai 1/2, Twist 1/2, Zeb 1/2, and ALDH1, as well as stem cell characteristics. The clinical onset of claudin-low breast cancer is at menopause age, and its histological grade is higher. This subtype of breast cancer is more likely to spread to lymph nodes than other subtypes. Claudin-low breast cancer is frequently accompanied by increased invasiveness and a poor prognosis. According to a clinical retrospective analysis, claudin-low breast cancer can achieve low pathological complete remission. At present, although several therapeutic targets of claudin-low breast cancer have been identified, the effective treatment remains in basic research stages, and no animal studies or clinical trials have been designed. The origin, molecular biological characteristics, pathological characteristics, treatment, and prognosis of CLBC are extensively discussed in this article. This will contribute to a comprehensive understanding of CLBC and serve as the foundation for the individualization of breast cancer treatment.

The long non-coding RNA ZFAS1 promotes colorectal cancer progression via miR200b/ZEB1 axis

BACKGROUND

Colorectal cancer (CRC) is a common tumor worldwide. CRC is influenced by several types of miRNAs and long non-coding RNAs. This study aims to evaluate the correlation of lncRNA ZFAS1/ miR200b/ ZEB1 protein with presence of CRC.

METHODS

Quantitative real-time polymerase chain reaction was used to measure serum expression of lncRNA ZFAS1 and microRNA-200b in 60 CRC patients and 28 control subjects. ZEB1 protein in serum was measured by ELISA.

RESULTS

Lnc ZFAS1 and ZEB1 were up-regulated in CRC patients in compare to control subjects while miR-200b was down-regulated. There was a linear correlation between ZAFS1 expression and miR-200b and ZEB1 in CRC.

CONCLUSION

ZFAS1 is a key player of CRC progression and could be a potential therapeutic target by sponging miR-200b. In-addition the association between ZFAS1, miR-200b and ZEB1 highlights their potential value as a novel diagnostic biomarker in human CRC.

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.

MicroRNAs with Multiple Targets of Immune Checkpoints, as a Potential Sensitizer for Immune Checkpoint Inhibitors in Breast Cancer Treatment

Breast cancer is the most common cancer type and the leading cause of cancer-associated mortality in women worldwide. In recent years, immune checkpoint inhibitors (ICIs) have made significant progress in the treatment of breast cancer, yet there are still a considerable number of patients who are unable to gain lasting and ideal clinical benefits by immunotherapy alone, which leads to the development of a combination regimen as a novel research hotspot. Furthermore, one miRNA can target several checkpoint molecules, mimicking the therapeutic effect of a combined immune checkpoint blockade (ICB), which means that the miRNA therapy has been considered to increase the efficiency of ICIs. In this review, we summarized potential miRNA therapeutics candidates which can affect multiple targets of immune checkpoints in breast cancer with more therapeutic potential, and the obstacles to applying miRNA therapeutically through the analyses of the resources available from a drug target perspective. We also included the content of "too many targets for miRNA effect" (TMTME), combined with applying TargetScan database, to discuss adverse events. This review aims to ignite enthusiasm to explore the application of miRNAs with multiple targets of immune checkpoint molecules, in combination with ICIs for treating breast cancer.

The role and application of transcriptional repressors in cancer treatment

Gene expression is modulated through the integration of many regulatory elements and their associated transcription factors (TFs). TFs bind to specific DNA sequences and either activate or repress transcriptional activity. Through decades of research, it has been established that aberrant expression or functional abnormalities of TFs can lead to uncontrolled cell division and the development of cancer. Initial studies on transcriptional regulation in cancer have focused on TFs as transcriptional activators. However, recent studies have demonstrated several different mechanisms of transcriptional repression in cancer, which could be potential therapeutic targets for the development of specific anti-cancer agents. In the first section of this review, "Emerging roles of transcriptional repressors in cancer development," we summarize the current understanding of transcriptional repressors and their involvement in the molecular processes of cancer progression. In the subsequent section, "Therapeutic applications," we provide an updated overview of the available therapeutic targets for drug discovery and discuss the new frontier of such applications.

Silencing of TP73-AS1 impairs prostate cancer cell proliferation and induces apoptosis via regulation of TP73

BACKGROUND

Prostate cancer is a malignant disease that severely affects the health and comfort of the male population. The long non-coding RNA TP73-AS1 has been shown to be involved in the malignant transformation of various human cancers. However, whether TP73-AS1 contributes to prostate cancer progression has not been reported yet. Accordingly, here we aimed to report the role of TP73-AS1 in the development and progression of prostate cancer and determine its relationship with TP73.

METHODS AND RESULTS

TP73-AS1-specific siRNA oligo duplexes were used to silence TP73-AS1 in DU-145 and PC-3 cells. Results indicated that TP73-AS1 was upregulated whereas TP73 was downregulated in prostate cancer cells compared to normal prostate cells and there was a negative correlation between them. Besides, loss of function experiments of TP73-AS1 in prostate cancer cells strongly induced cellular apoptosis, interfered with the cell cycle progression, and modulated related pro- and anti-apoptotic gene expression. Colony formation and migration capacities of TP73-AS1-silenced prostate cancer cells were also found to be dramatically reduced.

CONCLUSIONS

Our findings provide novel evidence that suggests a chief regulatory role for the TP73-TP73-AS1 axis in prostate cancer development and progression, suggesting that the TP73/TP73-AS1 axis can be a promising diagnostic and therapeutic target for prostate cancer.

miR-320a promotes p53-dependent apoptosis of prostate cancer cells by negatively regulating TP73-AS1 invitro

TP73 antisense RNA 1 (TP73-AS1) is an oncogenic long non-coding RNA that is activated in several types of cancers. It has been shown that the activity of TP73-AS1 is controlled by several miRNAs, but post-transcriptional mechanisms that regulate TP73-AS1 activity in prostate cancer remain highly elusive. Accordingly, in the present study, we aimed to determine the miRNAs that are involved in the regulation of TP73-AS1 in prostate cancer and to show the effects of these molecules on the malignant proliferation of prostate cancer cells. Remarkably, colony formation and cell migration were suppressed while cell cycle arrest and apoptosis were induced in prostate cancer cells overexpressing miR-200a and miR-320a. miR-200a and miR-320a were found to be upregulated in TP73-AS1 suppressed prostate cancer cells. Also, TP73-AS1 was shown to be downregulated following miR-200a and miR-320a overexpression. However, overexpression of miR-320a had no significant effect on the expression of TP73. Further analysis revealed that miR-320a induces p53-dependent apoptosis. Consequently, our findings indicate that miR-320a induces p53-dependent apoptosis by negatively regulating TP73-AS1 long non-coding RNA.

TP73-AS1 as a predictor of clinicopathological parameters and prognosis in human malignancies: a meta and bioinformatics analysis

Background

Long non-coding RNA P73 antisense RNA 1 T (non-protein coding), also known as Lnc RNA TP73-AS1, is dysregulated in various tumors but the correlation between its expression and clinicopathological parameters and/or prognoses in cancer patients is inconclusive. Here, we performed a meta-analysis to evaluate the prognostic value of Lnc RNA TP73-AS1 for malignancies.

Methods

We systematically searched four online databases including PubMed, the Web of Science, Embase, and the Cochrane Library for eligible articles published up to June 29/2020. Odds ratios (ORs) and Pooled hazard ratios (HRs) with 95% confidence intervals (95% CIs) were used to assess the association of TP73-AS1 expression with prognostic and clinicopathological parameters. We further validated TP73-AS1 expression in various malignancies and its potential prognostic value using the GEPIA online database. We predicted potential biological processes and relevant signal mechanisms through the public databases.

Results

A total of 26 studies examining 14 cancers were analyzed to evaluate the relationship between TP73-AS1 expression, clinicopathological features and prognostic indicators. The results indicated that TP73-AS1 expression markedly correlates with TNM stage (OR = 3.27,95% CI:2.43–4.39, P < 0.00001), tumor size (OR = 3.00, 95%CI:2.08–4.35, P < 0.00001), lymph node metastasis (OR = 2.77, 95%CI:1.42–5.38,P < 0.00001) and distant metastasis (OR = 4.50,95%CI:2.

62–7.73,P < 0.00001). No correlation with age (OR = 1.12,95%CI:0.77–1.64, P > 0.05), gender (OR = 1.08, 95%CI:0.84–1.38, P > 0.05) or differentiation (OR = 1.39, 95%CI:0.71–2.70, P = 0.340) was observed. TP73-AS1 overexpression was a biomarker of poor Overall survival(OS)(HR = 1.85,95%CI:1.53–2.22, P < 0.00001) and Disease-Free-Survival (DFS) (HR = 1.57,95%CI:1.03–2.42, P < 0.05). Dysregulated TP73-AS1 expression and its prognostic value in various cancers was validated based on The Cancer Genome Atlas (TCGA). Further biological function predictions indicated that TP73-AS1 was involved in pro-oncogenic signaling.

Conclusions

The upregulation of Lnc RNA TP73-AS1 was related to detrimental clinicopathological parameters and can be considered an indicator of poor prognosis for cancer malignancies.

Analysis of the Role and Mechanism of ZEB1 in Regulating Cervical Carcinoma Progression via Modulating PD-1/PD-L1 Checkpoint

Background

Cervical carcinoma (CC) is a common and highly malignant tumor in women. The involvement of zinc finger E-box binding homeobox 1 (ZEB1) in many kinds of tumors has been well-documented; however, its role and mechanism in CC remain to be clarified.

Objective

This study investigated the mechanism of ZEB1 in modulating the growth and metastasis of CC cells.

Methods

The expression of ZEB1 in CC tissues and adjacent normal counterparts was determined by reverse transcription-polymerase chain reaction (RT-PCR). The correlation between ZEB1 and patient clinicopathological indexes was analyzed. In vitro, gain and loss functions of ZEB1 were performed in C-33A and HeLa cell lines. The proliferation, migration, and invasion of CC cells were detected by Cell Counting Kit-8 (CCK-8) assay and transwell assay, respectively. The expression levels of apoptosis-related proteins such as BCL2-associated X (Bax), B-cell lymphoma-2 (Bcl2), and Caspase-3, as well as epithelial-mesenchymal transition (EMT)-associated proteins including E-cadherin, Vimentin, and Snail, were measured by Western blotting. In addition, the targeting relationship between ZEB1 and programmed death 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) was predicted by bioinformatics and further verified by dual-luciferase reporter assay.

Results

ZEB1 was significantly up-regulated in CC tissues compared with normal counterparts. ZEB1 overexpression promoted the migration, proliferation, and invasion of CC cells and inhibited apoptosis, while knocking down ZEB1 contributed to the opposite effects. In addition, experiments on related mechanisms confirmed that ZEB1 targeted the 3'EUTR terminal of PD-1/PD-L1 and negatively regulated its expression. And an interaction between ZEB1 and PD-1/PD-L1 was identified.

Conclusion

ZEB1 can promote the proliferation and metastasis of CC cells via modulating the PD-1/PD-L1 checkpoint.

Metastatic EMT Phenotype Is Governed by MicroRNA-200-Mediated Competing Endogenous RNA Networks

Epithelial–mesenchymal transition (EMT) is a fundamental physiologically relevant process that occurs during morphogenesis and organ development. In a pathological setting, the transition from epithelial toward mesenchymal cell phenotype is hijacked by cancer cells, allowing uncontrolled metastatic dissemination. The competing endogenous RNA (ceRNA) hypothesis proposes a competitive environment resembling a large-scale regulatory network of gene expression circuits where alterations in the expression of both protein-coding and non-coding genes can make relevant contributions to EMT progression in cancer. The complex regulatory diversity is exerted through an array of diverse epigenetic factors, reaching beyond the transcriptional control that was previously thought to single-handedly govern metastatic dissemination. The present review aims to unravel the competitive relationships between naturally occurring ceRNA transcripts for the shared pool of the miRNA-200 family, which play a pivotal role in EMT related to cancer dissemination. Upon acquiring more knowledge and clinical evidence on non-genetic factors affecting neoplasia, modulation of the expression levels of diverse ceRNAs may allow for the development of novel prognostic/diagnostic markers and reveal potential targets for the disruption of cancer-related EMT.

Nano-Coated si-SNHG14 Regulated PD-L1 Expression and Decreased Epithelial-Mesenchymal Transition in Nasopharyngeal Carcinoma Cells

To investigate the expression characteristics of long non-coding RNA SNHG14 in nasopharyngeal carcinoma (NPC) and its effects on epithelial-mesenchymal transition and development of nano-coated si-SNHG14 as an anti-tumor agent. The SNHG14 expression in cancerous and adjacent non-cancerous tissues was monitored using reverse transcriptionpolymerase chain reaction (RT-PCR). Gain- and loss-of-function experiments tested the regulation of SNHG14, miR- 5590-3p, and ZEB1 on PD-L1. The binding association between the above three factors was verified using bioinformatics analysis. EMT-related E-cadherin, N-cadherin, and Vimentin were tested using Western blot. Animal experiments in nude mice verified the function of SNHG14 in the EMT of NPC in vivo. The nano-coated si-SNHG14 was developed as an anti-tumor agent and was verified NPC cell in vitro. SNHG14 was upregulated in NPC tissues. Knocking down SNHG14 markedly inhibited the EMT of NPC. Additionally, the expression of ZEB1 was positively related to that of the SNHG14, while it was inversely correlated with that of miR-5590-3p. Moreover, ZEB1 transcription upregulated PD-L1 and promoted the EMT, while SNHG14 could accelerate the EMT of NPC in vivo by regulating the PD-1 and PD-L1. SNHG14-miR-5590- 3p-ZEB1 positively regulated PD-L1 and facilitate the EMT of NPC. Nano-coated si-SNHG14 significantly downregulated PD-L1 expression and decreased EMT.

Association of a novel antisense lncRNA TP73-AS1 polymorphisms and expression with colorectal cancer susceptibility and prognosis

BACKGROUND

TP73-AS1 is a novel antisense long noncoding RNA and plays an important role in cell proliferation and cancer development. However, the link between TP73-AS1 and colorectal cancer (CRC) has not yet been reported.

OBJECTIVE

To explore the association of genetic variants in TP73-AS1 and its expression with CRC susceptibility and prognosis.

METHODS

A case-control study (including 507 CRC cases and 503 controls) and bioinformatics analysis were conducted.

RESULTS

rs9800 polymorphism was significantly related to higher risk in CRC [adjusted odds ratio (AOR) = 1.33, 95% confidence interval (CI) = 1.02-1.75, P = 0.034 in heterozygote codominant model]. There was no difference between TP73-AS1 polymorphisms and different tumor node metastasis (TNM) stages in the adjusted model. Moreover, TP73-AS1 expression level was positively related to different TNM stages. After adjusted for age, gender and TNM, higher TP73-AS1 expression levels were related to shorter recurrence-free survival time [hazard ratio (HR) = 1.66, 95% CI = 1.02-2.71, P = 0.043].

CONCLUSION

TP73-AS1 polymorphisms and expression may be associated with susceptibility and prognosis of CRC.

The regulatory role of antisense lncRNAs in cancer

Antisense long non-coding RNAs (antisense lncRNAs), transcribed from the opposite strand of genes with either protein coding or non-coding function, were reported recently to play a crucial role in the process of tumor onset and development. Functionally, antisense lncRNAs either promote or suppress cancer cell proliferation, migration, invasion, and chemoradiosensitivity. Mechanistically, they exert their regulatory functions through epigenetic, transcriptional, post-transcriptional, and translational modulations. Simultaneously, because of nucleotide sequence complementarity, antisense lncRNAs have a special role on its corresponding sense gene. We highlight the functions and molecular mechanisms of antisense lncRNAs in cancer tumorigenesis and progression. We also discuss the potential of antisense lncRNAs to become cancer diagnostic biomarkers and targets for tumor treatment.

Vasculogenic Mimicry in Breast Cancer: Clinical Relevance and Drivers

In solid tumors, vasculogenic mimicry (VM) is the formation of vascular structures by cancer cells, allowing to generate a channel-network able to transport blood and tumor cells. While angiogenesis is undertaken by endothelial cells, VM is assumed by cancer cells. Besides the participation of VM in tumor neovascularization, the clinical relevance of this process resides in its ability to favor metastasis and to drive resistance to antiangiogenic therapy. VM occurs in many tumor types, including breast cancer, where it has been associated with a more malignant phenotype, such as triple-negative and HER2-positive tumors. The latter may be explained by known drivers of VM, like hypoxia, TGFB, TWIST1, EPHA2, VEGF, matrix metalloproteinases, and other tumor microenvironment-derived factors, which altogether induce the transformation of tumor cells to a mesenchymal phenotype with a high expression rate of stemness markers. This review analyzes the current literature in the field, including the participation of some microRNAs and long noncoding RNAs in VM-regulation and tumorigenesis of breast cancer. Considering the clinical relevance of VM and its association with the tumor phenotype and clinicopathological parameters, further studies are granted to target VM in the clinic.

Differential non-coding RNAs expression profiles of invasive and non-invasive pituitary adenomas

Background

Pituitary adenoma (PA) accounts for 10–15% of all intracranial neoplasms. Despite their benign nature, PA often shows invasive growth. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are a class of non-coding RNAs that play important roles in PA initiation and progression.

Aim

The aim of this study was to find specific profiles of miR-200a and long non-coding RNA (lncRNA) antisense non-coding RNA in the INK4 locus (ANRIL) in PA based on a comparative study using Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) analyses of tumor tissue and plasma.

Methods

Plasma and PA tissue samples were obtained from two groups of included patients (15 invasive and 15 non-invasive PA). In addition, plasma samples from patients with invasive PA have collected pre- and post-operation. Plasma and tissue samples subjected to qRT-PCR analyses for the expression levels of miR-200a and lncRNA ANRIL.

Results

The expression levels of miR-200a and lncRNA ANRIL were increased in tissue samples patients with invasive PA than in the patients with non-invasive PA. In addition, the expression levels of circulating miR-200a and lncRNA ANRIL were increased in patients with invasive PA than in patients with non-invasive PA in the pre-operation period. However, the expression level of plasma circulating miR-200a and lncRNA ANRIL was decreased in patients with invasive PA in the post-operation period. Our results depicted a miR-200a and lncRNA ANRIL expression in tissue and plasma samples in the patients with invasive PA. In addition, Receiver Operating Characteristic (ROC) curve was used to evaluate the diagnostic value of these circulating miR-200a and lncRNA ANRIL.

Conclusion

The expression of these tumor-associated ncRNAs has been elevated in the PAs. Therefore, miR-200a and lncRNA ANRIL represents as biomarkers for diagnosis and potential targets for novel invasive PA treatment strategies.

MiR-200a with CDC7 as a direct target declines cell viability and promotes cell apoptosis in Wilm's tumor via Wnt/β-catenin signaling pathway

MiR-200a acts as a key role in tumor malignant progression. This work purposed to assess the function of miR-200a in Wilm's tumor. Based on bioinformatics analysis, the expression, prognostic value and related pathways of miR-200a and CDC7 (a potential downstream molecule of miR-200a) in Wilm's tumor were analyzed. qRT-PCR was conducted to confirm the miR-200a level in Wilm's tumor cells. The luciferase reporter assay was carried out to verify the binding of miR-200a to 3'-UTR of CDC7. Then, the impacts of miR-200a and CDC7 on cell viability and apoptosis were measured using CCK-8 and flow cytometry assays. Also, western blot was applied to measure the expression of CDC7 as well as Wnt/β-catenin signaling pathway-related proteins and apoptosis proteins. Herein, we revealed that miR-200a was lowly expressed in Wilm's tumor tissues and cells and the low miR-200a expression is closely bound up with death and poor outcomes. Moreover, miR-200a directly targeted and inhibited CDC7 in Wilm's tumor cells. Biological function experiments illustrated that overexpression of miR-200a reduced the viability and elevated the apoptosis of Wilm's tumor cells, while overexpression of CDC7 reversed the inhibitory impact of miR-200a on cell viability and the promoting impact of miR-200a on cell apoptosis. Besides, we revealed that miR-200a/CDC7 axis can decrease the expression of β-Catenin, Cyclin D1 and C-Myc as well as the phosphorylation of GSK-3β, thus inhibiting the Wnt/β-catenin signaling pathway. Furthermore, blocking the Wnt/β-catenin signaling pathway caused an increase on cell apoptosis, while overexpression of CDC7 can reverse these impacts. Collectively, miR-200a/CDC7 axis involved in regulating the malignant phenotype of Wilm's tumor through Wnt/β-catenin signaling pathway, which provides a theoretical basis for targeted molecular therapy of Wilm's tumor.

H19 Knockdown Suppresses Proliferation and Induces Apoptosis by Regulating miR-130a-3p/SATB1 in Breast Cancer Cells

Purpose

Breast cancer (BC) is the most common cancer in women. Emerging evidence has demonstrated that lncRNAs play an important role in BC. The objective of this study was to investigate the impact of the long non-coding RNA (lncRNA), H19/miRNA-130a-3P/special AT-rich sequence-binding protein-1 (SATB1) axis on BC progression.

Materials and Methods

Expression of lncRNA and RNA was quantified via RT-qPCR. CCK-8, colony formation, wound healing, transwell, and flow cytometric analyses were used to analyze the proliferation, migration, invasion and apoptosis of cells. A dual-luciferase reporter assay and a RNA immunoprecipitation (RIP) assay were used to assess molecular binding. Protein levels were measured by Western blotting. The function of the lncRNA H19 (hereafter referred to as H19) was examined by xenotransplantation.

Results

We demonstrated that H19 expression was higher in cancer tissues and cancer cell lines than in adjacent non-tumor tissues and normal cell lines, respectively. H19 silencing inhibited the proliferation, migration and invasion of BC cells, and induced apoptosis. In addition, H19 directly bound to miR-130a-3p and downregulated its expression. We further demonstrated that H19 sponged miRNA-130a-3p, which resulted in SATB1 upregulation, thus promoting BC progression. Silencing of H19 substantially suppressed BC tumorigenesis in vivo.

Conclusion

Our data uncovered a novel mechanism of BC progression based on the H19-miR-130a-3p-SATB1 axis.

Role of long non-coding RNA TP73-AS1 in cancer

Cancer incidence rate has increased so much that it is the second leading cause of deaths worldwide after cardiovascular diseases. Sensitive and specific biomarkers are needed for an early diagnosis of cancer and in-time treatment. Recent studies have found that long non-coding RNAs (lncRNAs) participate in cancer tumorigenesis. LncRNA P73 antisense RNA 1T (TP73-AS1), also known as KIAA0495 and p53-dependent apoptosis modulator (PDAM), is located in human chromosomal band 1p36.32 and plays a crucial role in many different carcinomas. This review summarizes current findings on the role of TP73-AS1 and its signaling pathways in various cancers, including glioma, esophageal squamous cell carcinoma (ESCC), hepatocellular carcinoma (HCC), colorectal cancer (CRC), osteosarcoma, gastric cancer (GC), clear cell renal cell carcinoma (ccRCC), breast cancer (BC), bladder cancer, ovarian cancer, cholangiocarcinoma (CCA), lung cancer, and pancreatic cancer. Its aberrant expression generally correlates with clinicopathological characterization of patients. Moreover, TP73-AS1 regulates proliferation, migration, invasion, apoptosis, and chemoresistance cancer mechanisms, both in vivo and in vitro, through different signaling pathways. Therefore, TP73-AS1 may be considered as a marker for diagnosis and prognosis, also as a target for cancer treatment.

Long non-coding RNA TP73-AS1 contributes to glioma tumorigenesis by sponging the miR-103a/GALNT7 pathway

Glioma is the most aggressive, commonly occurring brain tumor in adults. Long non-coding RNAs (lncRNAs) are among the gene expression regulators in cancer development. Previous research posited that the up-regulation of LncRNA TP73-AS1 (TP73-AS1) in glioma is linked to low survival rates. However, the precise LncRNA TP73-AS1 mechanism in glioma remains unknown. Herein, we found that TP73-AS1 was up-regulated in glioma and was associated with a dismal prognosis. The silencing of TP73-AS1 repressed the multiplication of glioma cells and caused cell death. Mechanistically, we identified that TP73-AS1 in glioma acts as a ceRNA by sequestering miR-103a from GALNT7. Further, the results of this study revealed a reciprocal expression between TP73-AS1 and miR-103a, and a positive regulation between TP73-AS1 and GALNT7, validating the identified mechanism. Besides, luciferase reporter assay identified miR-103a as the direct binding site of both TP73-AS1 and GALNT7. Moreover, the findings of CCK-8 and colony-formation assays indicated that exogenous expression of GALNT7 reversed TP73-AS1-induced division inhibition of glioma cells. Altogether, our results established that TP73-AS1 facilitates the progression of glioma through competing for endogenous RNA (ceRNA) in a TP73-AS1/miR-103a/GALNT7 loop.

Long Non-Coding RNA TP73-AS1 Promotes the Development of Lung Cancer by Targeting the miR-27b-3p/LAPTM4B Axis

Purpose

Long non-coding RNA P73 antisense RNA 1T (TP73-AS1) is a newly discovered lncRNA involved in the occurrence and development of several cancers. However, its role in lung cancer has not been well investigated yet.

Methods

The expressions of TP73-AS1, microRNA-27b-3p (miR-27b-3p) and lysosomal-associated protein transmembrane-4 Beta (LAPTM4B) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The cell proliferation, apoptosis, migration and invasion were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Annexin V-FITC/PI and transwell assays, respectively. Tumor xenografts were applied to explore the role of TP73-AS1 in vivo. The target relationship was predicted by StarBase v.2.0 or TargetScan and confirmed by luciferase reporter assay. Pearson's coefficient assay was applied to assess the expression correlation between two groups. Protein expression levels were detected by Western blot.

Results

We found that TP73-AS1 was strikingly up-regulated in lung cancer tissues and cells. TP73-AS1 depletion inhibited the growth and metastasis of lung cancer cells in vitro. Furthermore, TP73-AS1 could act as an endogenous sponge by directly binding miR-27b-3p, and a notable inverse correlation between them was also discovered. Importantly, knockdown of miR-27b-3p could reverse the inhibitory effects of TP73-AS1 depletion on the growth and metastasis of lung cancer cells. Besides, LAPTM4B was directly targeted by miR-27b-3p and could be co-regulated by TP73-AS1 and miR-27b-3p in lung cancer cells. Silencing TP73-AS1 hampered tumor growth by regulating miR-27b-3p/LAPTM4B axis in vivo.

Conclusion

TP73-AS1 promoted the progression of lung cancer through regulating miR-27b-3p/LAPTM4B axis and it might be a potential target for diagnosis and treatment of lung cancer.

Regulation of Breast Cancer Progression by Noncoding RNAs

BACKGROUND

Breast cancer (BC) is the cardinal cause of cancer-related deaths among women across the globe. Our understanding of the molecular mechanisms underlying BC invasion and metastasis remains insufficient. Recent studies provide compelling evidence on the prospective contribution of noncoding RNAs (ncRNAs) and the association of different interactive mechanisms between these ncRNAs with breast carcinogenesis. MicroRNAs (small ncRNAs) and lncRNAs (long ncRNAs) have been explored extensively as classes of ncRNAs in the pathogenesis of several malignancies, including BC.

OBJECTIVE

In this review, we aim to provide a better understanding of the involvement of miRNAs and lncRNAs and their underlying mechanisms in BC development and progression that may assist the development of monitoring biomarkers and therapeutic strategies to effectively combat BC.

CONCLUSION

These ncRNAs play critical roles in cell growth, cell cycle regulation, epithelialmesenchymal transition (EMT), invasion, migration, and apoptosis among others, and were observed to be highly dysregulated in several cancers. The miRNAs and lncRNAs were observed to interact with each other through several mechanisms that governed the expression of their respective targets and could act either as tumor suppressors or as oncogenes, playing a crucial part in breast carcinogenesis.

MicroRNAs and Their Influence on the ZEB Family: Mechanistic Aspects and Therapeutic Applications in Cancer Therapy

Molecular signaling pathways involved in cancer have been intensively studied due to their crucial role in cancer cell growth and dissemination. Among them, zinc finger E-box binding homeobox-1 (ZEB1) and -2 (ZEB2) are molecules that play vital roles in signaling pathways to ensure the survival of tumor cells, particularly through enhancing cell proliferation, promoting cell migration and invasion, and triggering drug resistance. Importantly, ZEB proteins are regulated by microRNAs (miRs). In this review, we demonstrate the impact that miRs have on cancer therapy, through their targeting of ZEB proteins. MiRs are able to act as onco-suppressor factors and inhibit the malignancy of tumor cells through ZEB1/2 down-regulation. This can lead to an inhibition of epithelial-mesenchymal transition (EMT) mechanism, therefore reducing metastasis. Additionally, miRs are able to inhibit ZEB1/2-mediated drug resistance and immunosuppression. Additionally, we explore the upstream modulators of miRs such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), as these regulators can influence the inhibitory effect of miRs on ZEB proteins and cancer progression.

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.

miR-18a activates Wnt pathway in ER-positive breast cancer and is associated with poor prognosis

Despite the established benefits of long‐term endocrine therapy, women with hormone receptor‐positive breast cancer remain at risk for late relapse. The basis of this is multi‐factorial including genetic, epigenetic, and host factors. In this study we have explored the epigenetic regulation of estrogen receptor (ER)‐dependent molecular and cellular phenotype by hsa‐miR‐18a‐5p using well‐established human ER‐positive (ER+) breast cancer cell lines. miR‐18a was overexpressed in MCF7 and ZR‐75‐1 and this led to an increase in the proliferative ability of the cells and concurrently resulted in decreased expression of luminal markers and higher expression of the basal marker, cytokeratin 14. The cells became more migratory with a significant repression of E‐cadherin and activation of the Wnt noncanonical pathway. We observed an activation of the planar cell polarity (PCP) pathway with increased activation of JNK pathway and eventually change in actin dynamics. There was increased F‐actin polymerization in cells with higher expression of miR‐18a. Examination of miR‐18a expression in a set of human ER+ breast cancer specimens showed a negative correlation between miR‐18a and ESR1 transcripts as well as ER protein. Kaplan‐Meier survival analysis of the cohort stratified by tumor hsa‐miR‐18a‐5p levels produced significant differences in disease‐free survival (log rank P < .05). This observation was independently validated in the METABRIC cohort. These data provide support for a role of hsa‐miR‐18a‐5p in altering the proliferative and migratory behavior of ER+ cells and its potential utility as a prognostic marker in clinical ER+ breast cancers.

Prognostic value and therapeutic potential of the long noncoding RNA TP73-AS1 in cancers: A systematic review and meta-analysis

Studies published in recent years have demonstrated that abnormal long noncoding RNA (lncRNA) antisense RNA to TP73 gene (TP73-AS1) expression is markedly associated with tumorigenesis, cancer progression and the prognosis of cancer patients. We aimed to explore the prognostic value of TP73-AS1 in multiple cancers. We comprehensively searched PubMed, Embase, Web of Science and the Cochrane Library (up to February 21, 2019). Hazard ratios (HRs), odds ratios (ORs) and the corresponding 95% confidence intervals (95% CIs) were calculated to estimate the association of TP73-AS1 with survival and clinicopathological features. The potential targets and pathways of TP73-AS1 in multiple cancers were summarized. Nineteen studies that involved thirteen types of cancers and 1329 cancer patients were identified as eligible for this meta-analysis. The results showed that high TP73-AS1 expression was significantly correlated with shorter overall survival (OS) (HR = 1.962, 95% CI 1.630-2.362) and disease-free survival (DFS) (HR = 2.050, 95% CI 1.293-3.249). The summary HRs of OS were 2.101 (95% CI 1.516-2.911) for gastric cancer (GC) and 1.920 (95% CI 1.253-2.942) for osteosarcoma. Subgroup analysis of OS demonstrated that the differential expression of TP73-AS1 in cancer tissues was a potential source of heterogeneity. Furthermore, increased TP73-AS1 expression was markedly associated with larger tumor size (OR = 2.759, 95% CI 1.759-4.330), advanced histological grade (OR = 2.394, 95% CI 1.231-4.656), lymph node metastasis (OR = 2.687, 95% CI 1.211-5.962), distant metastasis (OR = 4.145, 95% CI 2.252-7.629) and advanced TNM stage (OR = 2.633, 95% CI 1.507-4.601). The results of Egger's test and sensitivity analysis verified the robustness of the original results. High TP73-AS1 expression can predict poor survival and poor clinicopathological features in cancer patients and TP73-AS1 might be a potential biomarker and therapeutic target.

Downregulation of transcription factor TCTP elevates microRNA-200a expression to restrain Myt1L expression, thereby improving neurobehavior and oxidative stress injury in cerebral palsy rats

Transcription factors have already been proposed to work on some human diseases. Yet the role of translationally controlled tumor protein (TCTP) in cerebral palsy (CP) remains elusive. This study intends to examine the mechanism of TCTP on CP by regulating microRNA-200a (miR-200a).CP models of rats were established referring to the internationally recognized improved hypoxic ischemic encephalopathy modeling method. The neuroethology of rats, ultrastructure and pathological condition in brain tissues of rats were observed through several assays. The expression of TCTP, miR-200a, myelin transcription factor 1-like (Myt1L), tyrosine hydroxylase (TH) and inducible nitric oxide synthase (iNOS) along with apoptosis in brain tissues of rats was detected. The levels of reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in brain tissues of rats were determined. The binding site between miR-200a and Myt1L was analyzed.TCTP and Myt1L were overexpressed and miR-200a was under-expressed in CP rats. Elevated miR-200a ameliorated neurobehavior of CP rats and pathological injury in brain tissues. Elevated miR-200a up-regulated TH, GSH, GSH-Px, and SOD levels, down-regulated iNOS, ROS, MDA, TNF-α, and IL-6 levels, and attenuated neuronal apoptosis in brain tissues of CP rats. Myt1L was a target gene of miR-200a.Altogether, our study suggested that diminution of transcription factor TCTP up-regulates miR-200a to limit Myt1L expression, thereby improving neurobehavior and oxidative stress injury in CP rats.

Association of TP73-AS1 gene polymorphisms with the risk and survival of gastric cancer in a Chinese Han Population

It was investigated that TP73-AS1(TP73 antisense RNA 1) could function as an oncogene in gastric cancer (GC). The expression and function of long noncoding RNAs (lncRNAs) could be impacted by single nucleotide polymorphisms (SNPs), which are related to cancer susceptibility and prognosis. This study was to reveal the association between lncRNAs TP73-AS1 polymorphisms (rs1181865 A > G, rs9800 G > C, rs3737589 A > G, rs2298222 G > A, rs7515164 C > A) and GC in 1000 GC cases and 1000 controls in a Chinese Han population. Rs3737589 G allele had significant associations with the increasing risk of GC (G vs. A: p = .005). Rs3737589 variant genotypes (AG + GG) were related to an increased risk of GC in the elder population (age ≥60), females, nonsmokers, nondrinkers, individuals living in urban, and individuals without family history of GC in stratified analyses. Rs3737589 variant genotypes (AG + GG) were related to the advanced depth of tumor invasion (T3 + T4). Besides, we found that GC patients with AG or GG genotype of rs3737589 had poorer overall survival (OS) than those with AA genotype (p < .05). Our findings showed that the lncRNA TP73-AS1 rs3737589 polymorphism might increase the risk of GC, and rs3737589 polymorphism could be a potential biomarker to predict the prognosis of GC patients.

Knockdown of long noncoding RNA TP73-AS1 suppresses the malignant progression of breast cancer cells in vitro through targeting miRNA-125a-3p/metadherin axis

BACKGROUND

TP73 antisense RNA 1 (TP73-AS1) is a long noncoding RNA which has been shown to be involved in the progression of multiple malignant tumors. Previous studies have demonstrated the oncogenic role of TP73-AS1 in breast cancer. However, its molecular mechanism remains largely unknown in breast tumorigenesis.

METHODS

Expression of TP63-AS1, miRNA-125a-3p (miR-125a) and metadherin (MTDH) was detected by real-time quantitative PCR and western blotting. The malignancy was evaluated by cell counting kit 8 (CCK-8), transwell assays, flow cytometry and western blotting. The target binding was confirmed by dual luciferase reporter assay. Xenograft tumor model was performed to detect tumor growth in vivo.

RESULTS

Expression of TP73-AS1 was higher in breast cancer tissues and cell lines. Biologically, its knockdown could promote cell apoptosis rate, and inhibit proliferative capacity, migration and invasion ability in HCC-70 and MB231 cells, accompanied with higher cleaved caspase 3 level and lower Ki67, N-cadherin and Vimentin level. Moreover, TP73-AS1 downregulation restrained the tumor growth of HCC-70 cells in vivo. Mechanically, TP73-AS1 functioned as a molecular "sponge" for miR-125a to modulate MTDH, a downstream target of miR-125a. Intriguingly, both miR-125a overexpression and MTDH silencing exerted a tumor-suppressive effect in the malignant progression of HCC-70 and MB231 cells, which was counteracted by TP73-AS1 upregulation and miR-125a downregulation, respectively.

CONCLUSION

Knockdown of TP73-AS1 inhibited cell proliferation, migration and invasion, but facilitated apoptosis in breast cancer cells in vitro through targeting miR-125a and upregulating MTDH, suggesting a novel TP73-AS1/miR-125a/MTDH pathway in the malignant progression of breast cancer.

Knockdown Of Long Non-Coding RNA TP73-AS1 Inhibited Cell Proliferation And Metastasis Through Wnt/β-Catenin Pathway In Lung Adenocarcinoma

Background

Various evidences showed that abnormally expressed long non-coding RNAs (lncRNAs) play important roles in the tumorigenesis and progression of malignancies. However, the exact role and regulatory mechanism of lncRNA TP73-AS1 in the pathogenesis and progression of lung adenocarcinoma remain to be further elucidated.

Purpose

The aim of this study was to investigate the functional role and underlying mechanism of lncRNA TP73-AS1 in lung adenocarcinoma progression.

Methods

RT-PCR assay was employed to detect TP73-AS1 expression in lung adenocarcinoma tissues and cells. The function of TP73-AS1 in lung adenocarcinoma progression was estimated by MTT assay, EdU assay, flow cytometry, Western blot, wound-healing assay and transwell assay.

Results

LncRNA TP73-AS1 expression was significantly increased in lung adenocarcinoma tissues and cell lines. Moreover, functional assays revealed that silencing of lncRNA TP73-AS1 could attenuate cell proliferation, migration, invasion and epithelial–mesenchymal transition of lung adenocarcinoma, while enhanced expression of lncRNA TP73-AS1 led to the opposite results. Additionally, lncRNA TP73-AS1 knockdown could facilitate cell apoptosis and overexpression of lncRNA TP73-AS1 inhibited cell apoptosis. In addition, we further determined that lncRNA TP73-AS1 regulated cell metastasis through inducing the activation of Wnt/β-catenin signaling pathway in lung adenocarcinoma.

Conclusion

Our results indicated that lncRNA TP73-AS1 may play an oncogenic role in lung adenocarcinoma progression, which provided a promising therapy strategy for the treatment of lung adenocarcinoma.

Long noncoding RNA TP73-AS1 in human cancers

Long noncoding RNAs (lncRNAs) play an important role in tumor development. With the development of sequencing technology, many new lncRNAs have been discovered. lncRNA TP73-AS1 is abnormally expressed in many cancers. A summary of the current literature related to TP73-AS1 reveals that TP73-AS1 mainly regulates the occurrence and development of tumors through the mechanism of competitive endogenous RNA (ceRNA). In addition, the abnormal expression of TP73-AS1 can regulate the malignant function of tumor cells through a variety of possible mechanisms. All evidence suggests that TP73-AS1 may be a potential diagnostic biomarker or a new cancer therapeutic target.

Long noncoding RNAs and exosomal lncRNAs: classification, and mechanisms in breast cancer metastasis and drug resistance

Breast cancer is the most common cancer, and the second cause of cancer-related deaths (after lung cancer) among women. Developing tumor metastasis and invasion is the most important cause of death in breast cancer patients. Several key factors participate in breast cancer metastasis including long noncoding RNAs (lncRNAs). lncRNAs are a category of cellular RNAs that are longer than 200 nucleotides in length. Accumulating evidence suggests that lncRNAs have the potential to be promising diagnostic, prognostic biomarkers and therapeutic targets in breast cancer. Understanding the role of lncRNAs and their mechanisms of functions might help to further discovery of breast cancer biological characteristics. In this review, we discuss physiological functions, epigenetic regulation, transcriptional regulation of lncRNAs, and their important role in tumor progression and metastasis. Some lncRNAs function as oncogenes and some function as tumor suppressors. Interestingly, recent reports depict that hypomethylation of promoters of lncRNAs play a pivotal role in cancer progression, suggesting the importance of epigenetic regulation. Furthermore, we discuss the role of lncRNAs in exosomes and their function in drug resistance, and therapeutic importance of exosomal lncRNAs in cancer biology. In summary, lncRNAs have a great potential to consider them as novel prognostic biomarkers as well as new therapeutic targets in breast cancer.

LINC00473/miR-497-5p Regulates Esophageal Squamous Cell Carcinoma Progression Through Targeting PRKAA1

Background: Esophageal squamous cell carcinoma (ESCC) is one of the esophageal cancers known as an aggressive malignant tumor. Long noncoding RNAs (lncRNAs) can be involved in the progression and development of cancers. lncRNA LINC00473 (LINC00473) was reported to exert an oncogenic influence on diverse cancers. However, neither the biological function nor the underlying mechanism of LINC00473 has been explored in ESCC. Aim of the Study: The aim of investigation is to explore the role of LINC00473 in ESCC. Methods: The expression of LINC00473, miR-497-5p, and protein kinase AMP-activated alpha 1 catalytic subunit (PRKAA1) was detected by reverse-transcription quantitative polymerase chain reaction assay. Cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays were carried out to measure cell proliferation. Cell migration was tested by transwell assay. Western blot assay was performed to examine the protein expression of PRKAA1, E-cadherin, N-cadherin, and Vimentin. The binding capacity between miR-497-5p and LINC00473 (or PRKAA1) was, respectively, studied by luciferase reporter and RNA immunoprecipitation assays. Pearson correlation analysis was adopted to analyze the correlation between miR-497-5p (or LINC00473) and PRKAA1. Results: LINC00473 presented much higher expression and LINC00473 suppression restrained the proliferation, migration, and epithelial-mesenchymal transition (EMT) process in ESCC cells. MiR-497-5p presented lower expression, binding with and negatively regulated by LINC00473 in ESCC. PRKAA1 was confirmed as a downstream target gene for miR-497-5p. PRKAA1 could combine with miR-497-5p, and LINC00473 knockdown or miR-497-5p overexpression downregulated the mRNA and protein expression of PRKAA1. At last, the inhibitory effects of LINC00473 knockdown on proliferation, migration, and EMT process were reversed by PRKAA1 overexpression in vitro and in vivo. Conclusions: LINC00473 regulates ESCC progression through miR-497-5p/PRKAA1 axis, which provides a new therapeutic strategy for ESCC patients.

Long non‑coding RNA TP73 antisense RNA 1 facilitates the proliferation and migration of cervical cancer cells via regulating microRNA‑607/cyclin D2

The present study aimed to explore the effect of the long non‑coding RNA TP73 antisense RNA 1 (TP73‑AS1) on cervical cancer progression. Cervical cancer and adjacent tissues were collected from 56 patients and assessed. In addition, HeLa and CaSki cells were transfected with various plasmids, inhibitors and corresponding controls, and then Cell Counting Kit‑8 and Transwell assays were used to detect the cell proliferation, migration and invasion abilities. Luciferase reporter gene assay was also performed in HeLa cells. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was used to investigate TP73‑AS1, microRNA‑607 (miR‑607) and cyclin D2 (CCND2) gene expression, while CCND2 protein expression was determined by western blot analysis. The results revealed that the TP73‑AS1 level was upregulated in cervical cancer tissues (P<0.05) and predicted a poor 5‑year overall survival (P<0.05). HeLa and CaSki cells transfected with siTP73‑AS1 exhibited reduced proliferation, migration and invasion abilities when compared with those in the siNC group (P<0.05). Furthermore, miR‑607 was found to be negatively regulated by TP73‑AS1, while CCND2 was negatively regulated by miR‑607. HeLa and CaSki cells transfected with siTP73‑AS1 exhibited lower CCND2 mRNA and protein expression levels compared with the siNC and siTP73‑AS1 + miR‑inhibitor groups (P<0.05). Compared with the siNC and siTP73‑AS1 + CCND2 overexpression groups, siTP73‑AS1‑transfected HeLa and CaSki cells had decreased proliferation, migration and invasion abilities (P<0.05). In conclusion, the findings suggested that upregulation of TP73‑AS1 promoted cervical cancer progression by promoting CCND2 via the suppression of miR‑607 expression.

Recently Evolved Tumor Suppressor Transcript TP73-AS1 Functions as Sponge of Human-Specific miR-941

MicroRNA (miRNA) sponges are vital components of posttranscriptional gene regulation. Yet, only a limited number of miRNA sponges have been identified. Here, we show that the recently evolved noncoding tumor suppressor transcript, antisense RNA to TP73 gene (TP73-AS1), functions as a natural sponge of human-specific miRNA miR-941. We find unusually nine high-affinity miR-941 binding sites clustering within 1 kb region on TP73-AS1, which forms miR-941 sponge region. This sponge region displays increased sequence constraint only in humans, and its formation can be traced to the tandem expansion of a 71-nt-long sequence containing a single miR-941 binding site in old world monkeys. We further confirm TP73-AS1 functions as an efficient miR-941 sponge based on massive transcriptome data analyses, wound-healing assay, and Argonaute protein immunoprecipitation experiments conducted in cell lines. The expression of miR-941 and its sponge correlate inversely across multiple healthy and cancerous tissues, with miR-941 being highly expressed in tumors and preferentially repressing tumor suppressors. Thus, the TP73-AS1 and miR-941 duo represents an unusual case of the extremely rapid evolution of noncoding regulators controlling cell migration, proliferation, and tumorigenesis.

LncRNA TP73-AS1 sponges miR-141-3p to promote the migration and invasion of pancreatic cancer cells through the up-regulation of BDH2

LncRNA TP73 antisense RNA 1T (TP73-AS1) plays an important role in human malignancies. However, the levels of TP73-AS1 and its functional mechanisms in pancreatic cancer metastasis remain unknown, and the clinical significance of TP73-AS1 in human pancreatic cancer is also unclear. In the present study, the levels of TP73-AS1 and its candidate target miR-141 in pancreatic cancer and adjacent normal tissue were detected using qRT-PCR. The association between TP73-AS1 levels and the clinicopathologic characteristics of pancreatic cancer patients were analyzed. The relationship between TP73-AS1 and miR-141, and miR-141 and its candidate target 3-hydroxybutyrate dehydrogenase type 2 (BDH2) was confirmed using dual-luciferase reporter assays. TP73-AS1 and/or miR-141 were knocked down using siRNA or an inhibitor in pancreatic cancer cells and cell migration and invasion then examined. The results showed that TP73-AS1 was up-regulated in pancreatic cancer tissue and cell lines. High levels of TP73-AS1 were correlated with poor clinicopathological characteristics and shorter overall survival. MiR-141 was a direct target for TP73-AS1, while BDH2 was a direct target for miR-141. The knockdown of TP73-AS1 significantly inhibited the migration and invasion of pancreatic cancer cells, while the miR-141 inhibitor significantly restored the migration and invasion. Therefore, TP73-AS1 positively regulated BDH2 expression by sponging miR-141. These findings suggest that TP73-AS1 serves as an oncogene and promotes the metastasis of pancreatic cancer. Moreover, TP73-AS1 could serve as a predictor and a potential drug biotarget for pancreatic cancer.

LBX2-AS1 is activated by ZEB1 and promotes the development of esophageal squamous cell carcinoma by interacting with HNRNPC to enhance the stability of ZEB1 and ZEB2 mRNAs

Long non-coding RNAs (lncRNAs) are a group of transcripts, which can regulate the progression of esophageal squamous cell carcinoma (ESCC). According to the data of TCGA, Ladybird homeobox 2 antisense RNA 1 (LBX2-AS1) is a highly expressed lncRNA in ESCC samples. Herein, we chose it for further study. Furtherly, dysregulation of LBX2-AS1 was identified in ESCC tissues with metastasis. Loss-of function assays were conducted and revealed that LBX2-AS1 knockdown suppressed ESCC cell migration and epithelial-mesenchymal transition (EMT). Zinc finger E-box binding homeobox 1 (ZEB1) and zinc finger E-box binding homeobox 2 (ZEB2) are two EMT-related transcription factors. Since LBX2-AS1 promoted the EMT progress and simultaneously enhanced the level of ZEB1 and ZEB2, we further investigated whether LBX2-AS1 promoted cell migration and EMT in ESCC by regulating ZEB1 and ZEB2. Mechanism investigations revealed that RNA binding protein heterogeneous nuclear ribonucleoprotein C (HNRNPC) could interact with LBX2-AS1, ZEB1 and ZEB2, simultaneously. The similar function of HNRNPC in regulating migration and EMT process was demonstrated. ZEB1 has been reported as a positive transcriptional regulator of lncRNA. Therefore, further mechanism analysis was made to demonstrate whether ZEB1 could regulate the transcription of LBX2-AS1. Collectively, our data showed that ZEB1-induced upregulation of LBX2-AS1 promoted cell migration and EMT process in ESCC via enhancing the stability of ZEB1 and ZEB2.

LncRNA TP73-AS1 predicts poor prognosis and functions as oncogenic lncRNA in osteosarcoma

TP73 antisense RNA 1 (TP73-AS1), a novel long noncoding RNA (lncRNA), has been suggested to be deregulated in various human cancers and serve as a tumor suppressor or promoter, depending on tumor types. The role of TP73-AS1 in osteosarcoma is still unknown. In our results, TP73-AS1 was highly expressed in osteosarcoma tissue samples and cell lines compared with matching adjacent nontumor tissue specimens and a normal human osteoblast cell line, respectively. Moreover, high expression of TP73-AS1 was statistically associated with advanced Enneking stage, large tumor size, present distant metastasis, and poor histological grade, while exhibiting no statistical association with age, sex, and tumor site. The survival analyses showed that patients with osteosarcoma with high expression of TP73-AS1 obviously had lower overall survival than osteosarcoma patients with low expression of TP73-AS1, and high expression of TP73-AS1 was an independent poor prognostic factor for osteosarcoma patients. The experiments in vitro indicated that inhibition of TP73-AS1 expression depressed osteosarcoma cell viability, migration, and invasion, and arrested cell cycle. In conclusion, TP73-AS1 serves as oncogenic lncRNA participated in osteosarcoma progression.

LncRNA TP73-AS1 promoted the progression of lung adenocarcinoma via PI3K/AKT pathway

Lung adenocarcinoma (LAD) is one of the most common malignancies that threats human health worldwide. Long non-coding RNAs (lncRNAs) have been reported to play significant roles in tumorigenesis and might be novel biomarkers and targets for diagnosis and treatment of cancers. TP73-AS1 is a newly discovered lncRNA involved in the tumorigenesis and development of several cancers. However, its role in LAD has not been investigated yet. In the present study, we first found that TP73-AS1 expression was markedly increased in LAD tissues and cell lines and its overexpression was strongly associated with poor clinical outcomes. Then the loss/gain-of-function assays elucidated that TP73-AS1 contributed to cell proliferation, migration, and invasion in vitro, and the in vivo experiments illustrated that its knockdown inhibited tumor growth and metastasis. What was more, we discovered that phosphoinositide 3-kinase and AKT (PI3K/AKT) pathway was activated both in LAD tissues and cell lines but inactivated under TP73-AS1 silence. Moreover, the activation of this pathway could rescue the inhibitory effects of TP73-AS1 suppression on LAD cellular processes partially. These data suggested that TP73-AS1 served as an oncogene in LAD partially through activating PI3K/AKT pathway and it could be a potential target for diagnosis and treatment of LAD.

Competing endogenous RNA (ceRNA) cross talk and language in ceRNA regulatory networks: A new look at hallmarks of breast cancer

Breast cancer (BC) is the most frequently occurring malignancy in women worldwide. Despite the substantial advancement in understanding the molecular mechanisms and management of BC, it remains the leading cause of cancer death in women. One of the main reasons for this obstacle is that we have not been able to find the Achilles heel for the BC as a highly heterogeneous disease. Accumulating evidence has revealed that noncoding RNAs (ncRNAs), play key roles in the development of BC; however, the involving of complex regulatory interactions between the different varieties of ncRNAs in the development of this cancer has been poorly understood. In the recent years, the newly discovered mechanism in the RNA world is "competing endogenous RNA (ceRNA)" which proposes regulatory dialogues between different RNAs, including long ncRNAs (lncRNAs), microRNAs (miRNAs), transcribed pseudogenes, and circular RNAs (circRNAs). In the latest BC research, various studies have revealed that dysregulation of several ceRNA networks (ceRNETs) between these ncRNAs has fundamental roles in establishing the hallmarks of BC development. And it is thought that such a discovery could open a new window for a better understanding of the hidden aspects of breast tumors. Besides, it probably can provide new biomarkers and potential efficient therapeutic targets for BC. This review will discuss the existing body of knowledge regarding the key functions of ceRNETs and then highlights the emerging roles of some recently discovered ceRNETs in several hallmarks of BC. Moreover, we propose for the first time the "ceRnome" as a new term in the present article for RNA research.