The Traces of Dysregulated lncRNAs-Associated ceRNA Axes in Retinoblastoma: A Systematic Scope Review

Abstract Purpose Long non-coding RNAs are an essential component of competing endogenous RNA regulatory axes and play their role by sponging microRNAs and interfering with the regulation of gene expression. Because of the broadness of competing endogenous RNA interaction networks, they may help investigate treatment targets in complicated disorders. Methods This study performed a systematic scoping review to assess verified loops of competing endogenous RNAs in retinoblastoma, emphasizing the competing endogenous RNAs axis related to long non-coding RNAs. We used a six-stage approach framework and the PRISMA guidelines. A systematic search of seven databases was done to locate suitable papers published before February 2022. Two reviewers worked independently to screen articles and collect data. Results Out of 363 records, fifty-one articles met the inclusion criteria, and sixty-three axes were identified in desired articles. The majority of the research reported several long non-coding RNAs that were experimentally verified to act as competing endogenous RNAs in retinoblastoma: XIST/NEAT1/MALAT1/SNHG16/KCNQ1OT1, respectively. At the same time, around half of the studies investigated unique long non-coding RNAs. Conclusions Understanding the many features of this regulatory system may aid in elucidating the unknown etiology of Retinoblastoma and providing novel molecular targets for therapeutic and clinical applications.


Introduction
Retinoblastoma (RB) is the most prevalent intraocular malignant tumor, accounting for 3% of juvenile malignancies. 1RB has a global incidence rate of around 1/15000, with no racial, regional, or gender disparities, resulting in 9,000 new cases every year. 2,3The typical age of diagnosis for bilateral RB is 12 months, while it is 24 months for unilateral RB.Bilateral RB initiation occurs in around 30-40% of cases.Only 6% of newly diagnosed RB instances were found to be hereditary, whereas 94% were sporadic. 2,4,5RB is a highly malignant tumor that most often causes mortality owing to cerebral metastasis, accounting for 1% of all newborn fatalities. 6ntreated RB often progresses quickly, damaging the ocular structure and resulting in blindness. 7Furthermore, the tumor may invade the brain directly via the optic nerve or migrate through the blood to the lung, bone, and other systemic organs. 8It impacts human health and quality of life and imposes a significant emotional, medical, and economic burden on patients and society.0][11][12] On the other hand, the need to accurately identify the mechanisms involved in all cancers from onset to progression and treatment is increasing and should be addressed with more studies. 13eanwhile, competing endogenous RNA (ceRNA) axes are part of the pathways studied in many malignancies discussed below.Still, their role in retinoblastoma studies has not been comprehensively investigated.Pier Paolo Pandolfi's lab introduced the ceRNA hypothesis in 2011, 14 which tried to explain how RNAs "talk" to one other, forming interactions that affect functional genetic information and may play important roles in clinical diseases.This idea is based on the fact that microRNAs (miRNAs) can find their unique target sites called miRNA response elements (MRE) in diverse RNA molecules, which can then be destroyed by the miRNA-RISC complex.As a result, miRNAs may facilitate regulatory cross-talk between the transcriptome's varied components, including mRNAs and non-coding RNAs (ncRNAs) such as pseudogenes, long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs).NcRNAs are divided into two categories based on their length: small ncRNAs (200 nucleotides) and lncRNAs (>200 nucleotides). 15,16MiRNAs are small ncRNAs that are roughly 22 nucleotides long and regulate gene expression at the post-transcriptional stage in a sequence-specific way. 17-19Among these, critical regulatory roles can be considered for miRNAs in the eye, including ocular neovascularization, with their dysregulation being related to eye pathologies. 20LncRNAs are the most numerous kinds of ncRNAs in the mammalian genome and are responsible for several biological processes within cells. 21However, lncRNAs have a different cellular function than mRNAs. 22urthermore, RNA transcription, translation, chromatin and DNA modifications, mRNA stability, and pre-RNA splicing are all dependent on lncRNAs. 23CircRNAs are a relatively new type of RNA that, unlike linear RNAs, are distinguished by a covalent link that connects the five 0 and three 0 ends and offers enhanced stability. 24Recent data shows that circRNA dysregulation may cause a variety of disorders, including neurological diseases, vascular inflammation, and some forms of cancer. 25everal research in recent years have confirmed the ceRNA theory, underscoring its role in disrupting equilibrium in the context of various diseases. 26So far, the mechanisms of ceRNA have been examined in the context of cancer, 27 including ovarian cancer, 28 colorectal cancer, 29 thyroid cancer, 30 bladder cancer, 31 gastric cancer, 32 cervical cancer, 33 pancreatic cancer, 34 lung cancer, 35 hepatocellular carcinoma, 36 and breast cancer. 37Because ceRNA interaction networks are multifactorial, they may be helpful in the research of diseases such as RB in terms of therapeutic targets because by targeting only one of them, the levels of numerous disease-related RNAs alter at the same time. 38In the present study, we conducted a comprehensive scoping review to assess confirmed ceRNA loops within the context of RB, explicitly emphasizing the lncRNA-ceRNA axis associated with RB pathogenesis, providing a promising avenue for therapeutic interventions.

Methods
We selected a systematic scoping review with a qualitative synthesis as an appropriate form of review, particularly regarding the involvement of the ceRNAs axis in all aspects of RB.[41]

Identifying the research question
In order to investigate, evaluate, and discuss all original studies on the ceRNAs axis in RB, we used the following questions to guide our article: � What studies have been done on the ceRNAs axis in RB? � What are the results and findings of these studies?

Search strategy
We conducted a systematic literature search using Pubmed, Scopus, Cochrane, Google Scholar, Embase, Web of Science, and ProQuest databases.The search did not include a filter to limit the results by date, language, subject, or publication type.In addition, review publications were investigated to decrease the potential for missing related articles."Eye Neoplasms" was a medical subject heading (MeSH) used in the PubMed search strategy, and "eye tumor," "intraocular lymphoma," "orbit tumor," "eye cancer," "orbit pseudotumor," "orbit pseudotumor," and "microRNA" were emtree, which is a list of subject headings unique to the Embase database.The most recent search was on February 27, 2022.EndNote 20 was used to manage the references.

Study selection
Studies of RBs regarding the ceRNAs axis in humans, cell lines, and animal model studies were screened from publications acquired throughout the search procedure.All kinds of publications were assessed, including journal articles, conference presentations, erratum, conference abstracts, and reports.The screening was conducted in two stages by two reviewers independently.At this point, the titles and abstracts of the publications were scrutinized based on Table 1.After screening the publications, the two reviewers collaborated to verify the screening results.The article's full text was evaluated, and any irrelevant articles were removed, ensuring that the articles were entirely congruent with the study questions.Any discrepancy in agreement with the third person's viewpoint was addressed.

Charting the data
After the attainment of the final articles that fulfill the research questions, we established the data-charting.Study variables were created using the following headings: First author, Year of publication, origin, Type of study, Human samples, Animal models, Cell lines, CeRNAa, Shared miRNA(s), Major findings, and References.Two reviewers

Collating, summarizing, and reporting the results
The findings derived from the articles were meticulously displayed in tables and charts and were subjected to a dual analysis framework that incorporated both quantitative and qualitative perspectives.We conducted a detailed numerical examination in the quantitative analysis phase, providing a descriptive overview of the research findings' extent, types, and distribution.This quantitative aspect aimed to quantify and synthesize the main discoveries, offering insights into the dimensions of the research landscape.Additionally, the data was placed within a broader framework, aligning with the approach advocated by Levac et al. 42 Regarding the qualitative analysis, we adopted a narrative approach to evaluate and report the findings, situating them within a coherent and meaningful narrative structure.This narrative review enabled us to extract significant insights and identify trends, thereby facilitating a deeper comprehension of the research context.

Results
A keyword search in seven databases yielded 363 records.In the meantime, four records were identified from other sources and added to the total number of articles.A total of 176 duplicate records were identified and deleted by Endnote software, and the total number of articles reached 190.After reviewing the titles and abstracts of the articles, 77 articles based on the research question were selected.At this phase, by reviewing the full text of 77 articles, 52 articles were included in Table S1 for the charting data stage.The process of selecting eligible articles and studies is designated in detail in Figure 1.Eligible studies have been published from 2018 to 2021.Based on the mentioned number, 1783 samples of RB patients and 1014 healthy controls were included in these studies.In most cases, the sex of patients and controls is not mentioned.In 24 studies, an animal model was

CeRNA hypothesis at a glance
In 2007, Ebert et al. created miRNA sponges, which are artificially generated miRNA inhibitors. 43,44Salmena et al. introduced the ceRNA hypothesis for the first time in 2011, with a growing number of experimental confirmations and the identification of endogenous miRNA sponges. 14In addition to the classic miRNA-RNA mode of action, it was proposed that there is also an RNA-miRNA-mRNA regulatory mechanism. 45The term "ceRNA" does not relate to a particular RNA but rather to a brand-new mechanism of gene expression control that describes an RNA mode of action. 23hen ceRNA expression is repressed, mRNAs are transcribed and exported to the cytoplasm, where they are targeted by the miRNA-RISC, resulting in rapid degradation, translational blockade, and gene expression decrease.Second, when ceRNA expression is active, there is competition for miRNA targeting and binding to the RISC complex, which reduces miRNA inhibition; the miRNA-RISC complex is segregated from the gene, resulting in enhanced gene expression. 46,47eRNAs bind miRNAs via identical MREs, so indirectly controlling gene expression competitively. 30This kind of competitive miRNA binding is also known as miRNA sponge action.According to this idea, any RNA that includes MREs may be classified as ceRNA.Its core is comprised of miRNAs, and its members include lncRNAs, cirRNAs, mRNAs, and pseudogenes, among other RNA molecules.RNAs that govern tumor growth play an essential role among those that may be employed as ceRNAs. 38In addition, since each mRNA contains several MREs, the potential for different miRNA pathways exists for each mRNA.Each miRNA interacts with numerous ceRNAs, resulting in the formation of the final "many-to-many" ceRNA networks (ceRNETs). 48CeRNETs, which include more RNA molecules than the miRNA regulatory network, are more sophisticated and intricate.As a result of aberrant ceRNA expression, they have an impact on the expression of a variety of target genes throughout the body, contributing to the advancement of cancer. 49Figure 3 demonstrates the most simplified ceRNA model.
According to research, ceRNAs play crucial roles in the formation and progression of cancer. 50Given the intricacy of the ceRNA network, this discovery is still in its early stages.At the moment, the most efficient strategy to uncover the ceRNA role in cancer is first to construct ceRNETs.It is a widely used research strategy to collect tissue samples and utilize microarrays or sequencing technologies or databases to gather information, screen various miRNAs, lncRNAs, and mRNAs, screen differentially expressed genes, and create ceRNETs to identify critical networks, and lastly, do functional enrichment analysis and survival analysis to uncover genes associated with cancer development and prognosis. 51,52The Cancer Genome Atlas (TCGA) database and the Gene Expression Omnibus (GEO) microarray datasets are the two most frequently utilized databases. 53dditionally, researchers have developed specialized tools to aid in the detection of ceRNA networks, such as ceRDB, 54 Linc2GO, 55 starBase v2.0, 56 lnCeDB, 57 and Cupid. 58

Diagnostic and therapeutic applications of ceRNA in cancer
Because the cancer transcriptome changes significantly from the normal counterparts, the ceRNA profile in cancer may likewise vary from the normal condition. 59In cancer, ceRNA quantity and activity are unregulated or reprogrammed, according to growing data. 28-37A recent bioinformatics analysis found a rewiring in the ceRNA profile in breast tissue when compared to matched normal tissue, with certain ceRNAs active in cancer cells but not in normal cells and vice versa. 60For example, the lncRNA plasmacytoma variant translocation 1 (PVT1), whose overexpression has been shown to have an antiapoptotic impact in breast cancer, 61 was discovered to operate as ceRNA in normal cells but not in breast cancer cells. 60These distinct ceRNA patterns in cancer and normal cells have the potential to be used as diagnostic markers in the future.MiRNAs have been postulated as possible anticancer treatment targets since they are implicated in the pathogenesis of a variety of human disorders, including cancer. 62,63Given that miRNAs are at the heart of ceRNA interaction, it is fair to consider cancer-related ceRNAs as therapeutic targets. 64,65Using artificial miRNA sponges containing several copies of MREs in tandem, researchers have been able to block oncogenic miRNAs and demonstrate tumor-suppressive effects in a variety of cancer cell lines, and xenograft animal models, including Ewing sarcoma, 66 renal cancer, 67 liver cancer, 68 and lung cancer. 69 order to bring the concept to fruition, however, several obstacles must first be overcome.To begin, ceRNAs with therapeutic promise should be ceRNA hubs or critical nodes with a large number of linkages to post-transcriptional regulatory components since cancer cells may avoid attacking non-essential nodes by using alternate routes. 70Second, how can we directly modify cancer-causing ceRNAs while leaving the rest of the others unaffected?Considering that ceRNAs are cross-linked to create a complex but holistic regulatory network, this is a problematic undertaking. 71,72Non-specific manipulation of the ceRNA network is harmful because it has the potential to change regular gene expression in an unanticipated way.Third, currently being explored strategies for successfully and selectively delivering ceRNA medicinal compounds into cancer cells.Vehicles designed for gene therapy delivery might be repurposed to deliver ceRNA therapeutic molecules in the future. 73t should be noted that the dynamics and limits of ceRNA regulation are influenced by various variables that form hierarchies within these complex networks. 74Seedsequence length, particular binding areas, and local AU content are critical factors in miRNA target-site effectiveness. 75he abundance and varieties of shared MREs influence ceRNA crosstalk, with optimal efficiency achieved when the concentrations of miRNAs and ceRNAs are nearly equivalent. 46The catalytic component of the RISC has been identified as a crucial element that governs the extent of competition in the regulation of ceRNAs. 46,76The intricate ceRNA hierarchies at an advanced level include several components, including nuclear miRNAs, overlapping senseantisense RNA transcripts, and the dynamics of mRNA 3' UTR.The aforementioned components jointly play a role in the complex regulatory hierarchies that influence the maintenance of RNA equilibrium within ceRNA networks. 74

LncRNAs as the primary part of ceRNAs
The ceRNA hypothesis proposes that specific lncRNAs have sponge-like effects on miRNAs that dampen mRNA effects. 27Indeed, many lncRNAs include miRNA-binding sites that control the expression of genes that encode proteins 56 In 2014, the lncRNA AK048451, also known as a cardiac hypertrophy-related factor, was shown to be a ceRNA of miR-489 and limit miR-489 expression by sequencespecific direct binding. 77Furthermore, aberrant lncRNA expression, mutations, and single nucleotide polymorphisms have been linked to tumor development and metastasis, and growing evidence suggests that networks of lncRNAs, miRNAs, and mRNAs play a significant role in the epithelial-to-mesenchymal transition (EMT), cancer initiation, and progression. 27,78,79As a result, lncRNAs and the lncRNAassociated ceRNA axis may be a potential therapeutic target for RB treatment.We conducted a scoping systematic review in this work and identified lncRNAs that were experimentally verified to behave as ceRNAs in RB in human studies.Some of the most well-known of these lncRNAs will be addressed below.The reported loops are shown in Figure 4.

XIST
Brown et al. originally described the lncRNA X-inactive specific transcript (XIST) in 1991. 80XIST is a transcript encoded by the XIST gene that functions as a major regulator of X-chromosome inactivation (XCI) in mammals.XCI is an epigenetic silencing of a random X chromosome in female cells to equalize X gene expression levels between males and females. 81,824][85] XIST also has anti-tumor characteristics in a limited fraction of malignancies, such as lymphomas. 86nterestingly, XIST has an opposing impact on the same disease, suggesting that XIST regulates cancer progression at several levels. 87Several studies in recent years have shown that XIST plays a role in the development of several different types of cancers through post-transcriptional gene regulation.
Notably, XIST can have a potential role in RB by acting in the ceRNA network as a primary lncRNA.Cheng et al. revealed that XIST causes an increase in E-box binding protein 1 (ZEB1) and E-box binding protein 2 (ZEB2) by sponging miR-101.In RB tissues and cells, the expression of XIST, ZEB1, and ZEB2 was raised, but miR-101 was decreased.XIST knockdown dramatically reduced proliferation, migration, invasion, and epithelial-mesenchymal transition, increasing apoptosis and caspase-3 activity.operates as an oncogene in metastatic and invasive lung cancer cells, promoting growth and cytoskeleton remodeling, migration, metastasis, and invasion.The highly expressed zinc-finger ZEB1 has been linked to the aggressiveness of several malignancies.Signal transmission and ZEB1 activation are critical in cancer transformation and EMT. 79emarkably, XIST was shown to be substantially expressed in RB patients.Xu et al. reported that cell proliferation, invasion, and EMT in RB increased after XIST overexpression, but apoptosis was reduced.MiR-142-5p is one of XIST's targets, and these effects were caused by the sponging of miR-142-5p. 89Similarly, XIST sponges miR-361-3p, and this process causes an increase in syntaxin 17 (STX17) expression levels and may act as an oncogene in RB. 90 In this regard, XIST also increases BDNF levels by increasing expression and sponging miR-191-5P on a single ceRNA axis to accelerate the proliferation, migration, and invasion of RB cells, thereby accelerating RB progression.On the other hand, a study on XIST silencing showed that silencing XIST by acting as a miR-204-5p sponge prevented RB progression and increased vincristine sensitivity in vitro and in vivo. 91onetheless, in general, studies in RB on XIST lncRNA have shown an increase of this lncRNA in the form of ceRNA axis, which, by sponging specific target miRNAs, increases the expression of genes that promote the development and progression of RB and even response to role therapy.

NEAT1
NEAT1 (nuclear paraspeckle assembly transcript 1) is transcribed from the familial tumor syndrome multiple endocrine neoplasia (MEN) type 1 loci on chromosome 11q13.1 and encodes two transcriptional variants NEAT1-1 (3756 bp) and NEAT1-2 (3756 bp) (22,743 bp). 92NEAT1 is present in both the nucleus and the cytoplasm. 93NEAT1 seems unnecessary for proper embryonic and adult development since mice deficient in NEAT1 usually develop. 94However, other research found that NEAT1 gene ablation resulted in abnormal morphogenesis of the mammary gland and lactation abnormalities. 95Further research is needed to determine whether the absence of NEAT1 impairs cell viability and development.NEAT1 exhibits typical cancer driver characteristics since it is crucial for tumor initiation and development, and its frequent dysregulation in malignancies correlates with clinical aspects such as metastasis, recurrence rate, and patient survival. 93,96tudies of ceRNA regulatory axes with NEAT1 have revealed the fact that NEAT1 plays a vital role in all stages of RB proliferation, progression, invasion, and metastasis.An essential point in this regard has been the increased expression of NEAT1 in all of these studies.Wang et al. revealed that NEAT1 promotes RB progression by sponging miR-124, and also, inhibition of miR-124 could reverse the effect of NEAT1 on RB cell proliferation, cycle arrest, apoptosis, and caspase3 and -9 activities. 88Similarly, Zhong et al. discovered that NEAT1 aided in the development of RB by sponging miR204 in RB and acting as a ceRNA to control C-X-C chemokine receptor type 4 (CXCR4 expression). 97he role of CXCR4 in the cancer process has been well studied.CXCR4 overexpression in cancer cells promotes tumor development, invasion, angiogenesis, metastasis, recurrence, and treatment resistance.CXCR4 antagonists have been demonstrated to impair tumor-stromal connections, make cancer cells more sensitive to cytotoxic medicines, and diminish tumor growth and metastatic burden. 98n the meantime, studies have been performed by silencing NEAT1 in RB.Chen et al. reported that By sponging miR-3619-5p to reduce SH3 domain protein 1 (LASP1) expression, NEAT1 silencing suppressed cell migration, invasion, and proliferation while inducing cell death and cycle arrest in RB cells. 99Cancer cells with high levels of LASP1 expression are likelier to have a high grade, large size, and extensive metastasis.Furthermore, LASP1 overexpression promotes tumor cell proliferation, migration, and invasion, perhaps via interactions with the cytoskeleton and enhanced nuclear translocation. 100Also, another research found that the LncRNA NEAT1 was up-regulated in RB tissues, cells, and serum and that individuals with high NEAT1 expression had a bad prognosis.Knocking down LncRNA NEAT1 may impair proliferation and invasion while hastening apoptosis.An allogeneic tumor allogeneic experiment showed that sh-NEAT1 injection might decrease tumor development.Furthermore, NEAT1 suppressed proliferation and invasion while promoting apoptosis through the miR-148b-3p/(Rho kinase 1) ROCK1 axis. 101ROCK1 has been discovered to be overexpressed in a variety of malignancies.Most notably, ROCK1, as a component of Stress Granules concerning the mammalian target of rapamycin complex 1 (mTORC1), has been shown to be involved in the formation, proliferation, metastasis, and resistance to chemotherapy of cancers. 102uan et al. confirmed that NEAT1 silencing inhibits cell migration, invasion, and EMT by downregulating Leucinerich a-2 glycoprotein 1 (LRG1) expression in RB through sponging miR-24-3p.LRG1 has been identified as a potential therapeutic target in colorectal cancer, which regulates Runt-related transcription factor 1 (RUNX1) expression. 103n the other hand, LRG1 is known as one of the main factors in vascular retinopathy, which indicates the critical role of this gene in eye health status. 104With an overview of the regulatory axes and components involved in this pathway, NEAT1 can be considered as one of the main lncRNAs involved in RB.

MALAT1
Metastasis associated in lung adenocarcinoma transcript 1 (MALAT1) is one of the best-researched lncRNAs.MALAT1 was discovered while searching for transcripts linked to metastasis and patient survival in non-small cell lung cancer (NSCLC). 105The primary sequence of the MALAT1 gene includes around 8000 kb and is well conserved across 33 mammalian species. 105The pancreas and lung are the two tissues with the most significant MALAT1 expression in the human body. 106Preclinical evidence shows that MALAT1 is widely expressed in human neoplasia and that it stimulates the proliferation and/or spread of tumor cells across a wide range of solid and hematological malignancies; consistently, meta-analyses have indicated that higher MALAT1 is associated with bigger tumor size, progressed tumor stage, and overall poor expectancy and that it may thus serve as a biomarker to determine either clinicopathological characteristics or prognostic outcome. 107,108tudies on MALAT-1 expression levels indicate an increase in this lncRNA in RB.Studies on MALAT-1 expression levels indicate an increase in this lncRNA in RB.Interestingly, MALAT1 is involved in all stages of proliferation, migration, invasion, apoptosis, and EMT. 109Wang et al. revealed that MALAT1, by acting on ceRNA regulatory axes, is predisposed to play an essential role in processes involved in RB.MALAT1 acted as a sponge for miR-20b-5p, increasing signal transducers and activators of transcription 3 (STAT3) expression.MALAT1 silencing and overexpression of miR-20b-5p might reduce RB cell growth and increase apoptosis. 110Notably, STAT3 activity promotes several cancer-related characteristics, including cell growth, proliferation, survival, immune evasion, metastasis, and angiogenesis. 111Likewise, Zhao et al. discovered that MALAT1 exerts its effect on proliferation, migration, invasion, apoptosis, and EMT by increasing the expression of ATPase family AAA domain-containing protein 2 (ATAD2) in the form of a ceRNA axis. 109ATAD2 has been linked to the development of numerous malignancies, with ATAD2 depletion suppressing invasion and cell migration. 112emarkably, increased MALAT1 expression is linked to increased budding uninhibited by benzimidazole 1 (BUB1) expression through the downregulation of miR-495-3p in the RB. 113However, given that MALAT1 sponges various miRNAs, it increases the expression of genes that are all involved in critical cellular mechanisms, and in particular, one of the genes that play an essential role in the mechanisms involved in cancer so that it can introduce MALAT1 as an important lncRNA in the form of ceRNA regulatory axes.

SNHG16
SNHG16 (Small nucleolar RNA host gene 16) has recently been identified as a cancer-related lncRNA encoded by a 7571 bp region on chromosome 17q25.1. 114nucleolar RNA host gene 16 (NHG16) was detected in neuroblastoma when it was initially discovered. 115SNHG16 expression has been shown to be dysregulated in several cancers, including colorectal cancer, 116 hepatocellular carcinoma, 117 osteosarcoma, 118 and glioma. 119According to recent research, SNHG16 expression is elevated in a variety of malignancies.More importantly, it has been shown that downregulation of SNHG16 in cancer cells decreases cell proliferation, 120 invasion, 121 and migration, 122 as well as apoptosis, 123 and results in reduced N-cadherin and increased E-cadherin expression, indicating that SNHG16 may potentially operate as an oncogenic lncRNA in cancer. 122HG16 in RB studies has shown an increase in the expression of this lncRNA in the form of ceRNA axes.Mechanistic studies revealed that SNHG16 worked as a sponge for miR-140-5p, regulating its expression in RB cells.In RB specimens, clinical evidence demonstrated a negative connection between SNHG16 and miR-140-5p.Inhibiting miR-140-5p partly alleviated the growth-suppressive effects of SNHG16 depletion on RB cells. 124SNHG16 was identified as a metastasis-specific oncogenic lncRNA in RB, and a new ceRNA regulation mechanism was discovered in which SNHG16 enhanced LASP1 expression by sponging miR-182-5p and miR-128-3p. 125Most notably, in another study in RB, LASP1 showed increased expression in a ceRNA axis, NEAT1/miR-3619-5p/LASP1. 99 However, in addition to the LASP1 potential in determining tumor size and grade, LASP1 should be recognized as an essential factor that is regulated by different pathways.

KCNQ1OT1
The lncRNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) is found on chromosome 11p15.5. 126Recent research has shown that the lncRNA KCNQ1OT1 is involved in a variety of biological processes, including cell growth, apoptosis, and drug resistance. 127,128Furthermore, the lncRNA KCNQ1OT1 is linked to the advancement of several malignancies, including breast cancer, 129 colorectal cancer, 130 tongue carcinoma, 131 and lung cancer. 132linicopathological features of cancer, such as survival rates, lymphatic metastasis, TNM stage, and tumor size, are also strongly connected with lncRNA KCNQ1OT1 expression levels. 133tudies on KCNQ1OT1 in RB have all been shown to increase the expression of this lncRNA.KCNQ1OT1 knockdown inhibited RB cell proliferation, migration, invasion, and survival.Wang et al. reported that there were two verified binding sites between KCNQ1OT1 and miR-153-3p, and KCNQ1OT1 can inhibit miR-153-3p expression in RB cells.HIF-1a is a miR-153-3p target gene that might be favorably regulated by KCNQ1OT1. 134(hypoxia-inducible factor-1 alpha) HIF-1a is one of the most well-known and influential genes in the field of cancer.HIF-1a has been identified as a significant cancer therapeutic target.Recent investigations have shown a substantial association between high HIF-1a levels and tumor metastasis, angiogenesis, poor patient prognosis, and tumor resistance treatment. 135Similar to the previous research, a related study discovered that directly sponging miR-134 silencing KCNQ1OT1 might reduce Rb cell proliferation, migration, and invasion.MiR-134 suppressed tumor growth in Rb cells by regulating tripartite motif protein 44 (TRIM44).As a result, by sponging miR-134 in Rb cells, KCNQ1OT1 might boost TRIM44 expression. 136Also, Zhang et al. revealed that KCNQ1OT1 reduces cell proliferation and migration and increases the apoptosis of cancer cells by sponging miR-124, increasing SP1 expression, and affecting the SIRT1/JNK signaling pathway. 137otably, SP1 has been identified as one of the cancer hallmarks, and it is over-expressed in many cancers and is related to poor prognosis. 138Since KCNQ1OT1 in the form of ceRNA network plays an essential role in RB in regulating the expression of essential genes such as SP1, TRIM44, and HIF1-a, which are some of the central genes in cancer, this makes it prone to further studies.

DANCR
Differentiation antagonizing non-protein coding RNA (DANCR or ANCR), which is found on human chromosome 4q12, was discovered in 2012 to decrease epithelial cell differentiation and was later shown to increase stemness in hepatocellular cancer cells. 139,140Much research has been done in current decades to better understand the DANCR 0 s role in cancer due to this discovery.DANCR is shown to be overexpressed in a variety of malignancies. 141,142The dysregulation of DANCR expression is intimately related to both biological processes and clinical pathogenic variables. 141,142 study concerning RB shows that DANCR functions as a ceRNA for miR-34c and miR-613, which control progression and metastasis in RB oncogenesis by targeting MMP-9, and that DANCR is regulated in RB straightforwardly.143 It should be noted that Matrix metalloproteinase (MMP-9) has the ability to break a wide range of extracellular matrix (ECM) proteins, which allows it control ECM remodeling.It can also cleave a wide range of plasma surface proteins, allowing them to be released from the cell surface.Invasion, metastasis, and angiogenesis are just a few of the processes that MMP-9 has been linked to in studies of cancer pathology.144

HEIH
High expression in hepatocellular carcinoma, also known as hepatocellular carcinoma up-regulated Enhancer of zeste homolog 2 (EZH2)-associated lncRNA (HEIH), is a newly discovered intergenic lncRNA on chromosome 5q35.3.The HEIH gene sequence is almost 1000 nucleotides long and may be translated to create transcript NR 045680.1. 145lthough HEIH RNA molecules may be found in both the cytoplasm and the nuclease, HEIH is primarily found in the cytoplasm. 146HEIH was initially identified and studied as an oncogenic lncRNA in hepatitis B virus (HBV)-related hepatocellular carcinoma due to its suppression of cell differentiation in G0/G1.It was hypothesized that HEIH was linked to the enhancer of EZH2 and that this link was essential for the suppression of the EZH2 target genes, which included p15, p16, p21, and p57. 147Subsequent research has shown that HEIH is improperly expressed in a variety of malignancies, and its dysregulation is strongly linked to carcinogenesis, impacting cancer patients' prognosis. 145EE1A (WEE1) is a tyrosine kinase that controls normal cells' G2/M checkpoints and mitotic timing.Inhibitory phosphorylation of CDK1 prevents cells from initiating mitosis and gives them time to repair their DNA. 148As a result, cancer cells with a faulty G1 checkpoint depend on the G2 checkpoint for DNA repair, 149 and targeting WEE1 in these cells causes premature mitosis and cell death. 150WEE1 is overexpressed in a variety of malignancies, including hepatocellular carcinoma, 151 breast cancers, 152 cervical cancers, 152 lung cancers, 152 squamous cell carcinoma, 153 glioblastoma, 154 medulloblastoma, 155 melanoma, 156 and ovarian cancers. 157However, Gao et al. revealed that WEE1 expression is also increased in the form of a ceRNA axis, in which HEIH increases the expression levels of WEE1 in RB by sponging miR-194-5p. 158This study highlights the role of HEIH in the mechanisms involved in RB and reveals its potential for further studies.

Limitations
The present study had several limitations.In this study, it was tried to discuss most of the lncRNAs that are better known and have been studied more in RB studies.Due to the limited form of a systematic study, it was not possible to discuss lncRNAs one by one in the form of ceRNA axes.On the other hand, in this study, we tried to cover all the details related to these regulatory axes and lncRNAs in Table 1 in the significant findings section.In the screening part of the studies, all care was taken not to miss a study, and three people collaborated in this part so that this study would include all the studies done in the field of RB, but this is possible due to an individual error that may have left a study off the table.

Conclusion
LncRNA-associated ceRNA regulation has physiologically essential impacts on a variety of disorders, elucidating pathogenic mechanisms and providing alternatives for novel therapeutics.This research also discovered that lncRNAs had an intriguing influence on essential genes, each of which could potentially be a hallmark of cancer.Thus, our attempts to comprehend various aspects of ceRNA regulation processes in RB pathogenesis give fresh insights into possible molecular targets, uncover ceRNA-based diagnostics, and create ceRNA-based therapeutic applications.

Figure 1 .
Figure 1.Search strategy flow chart based on the PRISMA flow diagram.

Figure 2 .
Figure 2. A. An overview of the LncRNAs proportion in ceRNA axes is considered in the qualified studies.The other part is lncRNAs in ceRNA.B. An overview of the type of studies.

Figure 3 .
Figure 3. CeRNA model's diagrammatic network.All transcriptome components, including lncRNAs, circRNAs, pseudogenes, and mRNAs, may co-regulate and interact via sponging shared miRNAs.Because of this, ceRNA dysregulation and biological alterations might occur as a consequence of transcripts that are differentially expressed.

Table 1 .
Inclusion and exclusion criteria.