Current status of long non-coding RNAs in human cancer with specific focus on colorectal cancer

Interaction of lncRNAs with mTOR in colorectal cancer: a systematic review

Colorectal cancer (CRC) is the third most widespread cancer and the fourth leading lethal disease among different societies. It is thought that CRC accounts for about 10% of all newly diagnosed cancer cases with high-rate mortality. lncRNAs, belonging to non-coding RNAs, are involved in varied cell bioactivities. Emerging data have confirmed a significant alteration in lncRNA transcription under anaplastic conditions. This systematic review aimed to assess the possible influence of abnormal mTOR-associated lncRNAs in the tumorigenesis of colorectal tissue. In this study, the PRISMA guideline was utilized based on the systematic investigation of published articles from seven databases. Of the 200 entries, 24 articles met inclusion criteria and were used for subsequent analyses. Of note, 23 lncRNAs were prioritized in association with the mTOR signaling pathway with up-regulation (79.16%) and down-regulation (20.84%) trends. Based on the obtained data, mTOR can be stimulated or inhibited during CRC by the alteration of several lncRNAs. Determining the dynamic activity of mTOR and relevant signaling pathways via lncRNAs can help us progress novel molecular therapeutics and medications.

Differential Expression of Non-Coding RNAs in Stem Cell Development and Therapeutics of Bone Disorders

Stem cells' self-renewal and multi-lineage differentiation are regulated by a complex network consisting of signaling factors, chromatin regulators, transcription factors, and non-coding RNAs (ncRNAs). Diverse role of ncRNAs in stem cell development and maintenance of bone homeostasis have been discovered recently. The ncRNAs, such as long non-coding RNAs, micro RNAs, circular RNAs, small interfering RNA, Piwi-interacting RNAs, etc., are not translated into proteins but act as essential epigenetic regulators in stem cells' self-renewal and differentiation. Different signaling pathways are monitored efficiently by the differential expression of ncRNAs, which function as regulatory elements in determining the fate of stem cells. In addition, several species of ncRNAs could serve as potential molecular biomarkers in early diagnosis of bone diseases, including osteoporosis, osteoarthritis, and bone cancers, ultimately leading to the development of new therapeutic strategies. This review aims to explore the specific roles of ncRNAs and their effective molecular mechanisms in the growth and development of stem cells, and in the regulation of osteoblast and osteoclast activities. Furthermore, we focus on and explore the association of altered ncRNA expression with stem cells and bone turnover.

Targeting lncRNAs of colorectal cancers with natural products

Non-coding RNA (ncRNA) is one of the functional classes of RNA that has a regulatory role in various cellular processes, such as modulation of disease onset, progression, and prognosis. ncRNAs, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), have been actively studied in recent years. The change in ncRNA levels is being actively studied in numerous human diseases, especially auto-immune disorders and cancers; however, targeting and regulating ncRNA with natural products to cure cancer has not been fully established. Recently many groups reported the relationship between ncRNA and natural products showing promising effects to serve as additional therapeutic approaches to cure cancers. This mini-review summarizes the aspects of lncRNAs related to cancer biology focusing on colorectal cancers that natural products can target.

Epigenetic regulation of gastrointestinal cancers mediated by long non-coding RNAs

Long noncoding RNAs (lncRNAs), as well-known modulator of the epigenetic processes, have been shown to contribute to normal cellular physiological and pathological conditions such as cancer. Through the interaction with epigenetic regulators, an aberrant regulation of gene expression can be resulted due to their dysregulation, which in turn, can be involved in tumorigenesis. In the present study, we reviewed the lncRNAs' function and mechanisms that contributed to aberrant epigenetic regulation, which is directly related to gastrointestinal cancer (GI) development and progression. Findings indicated that epigenetic alterations may involve in tumorigenesis and are valuable biomarkers in case of diagnosing, assessing of risk factors, and predicting of GI cancers. This review summarized the accumulated evidence for biological and clinical application to use lncRNAs in GI cancers, including colorectal, gastric, oral, liver, pancreatic and oesophageal cancer.

A Study to Investigate the Role of Noncoding RNA miR146 Alpha as a Potential Biomarker in Prostate Cancer

There is a need for additional biomarkers for the diagnosis and prognosis of prostate cancer. MicroRNAs are a class of non-protein coding RNA molecules that are frequently dysregulated in different cancers including prostate cancer and show promise as diagnostic biomarkers and targets for therapy. Here we describe the role of micro RNA 146 a (miR-146a) which may serve as a diagnostic marker for prostate cancer, as indicated from the data presented in this report. Also, a pilot study indicated differential expression of miR-146a in prostate cancer cell lines and tissues from different racial groups. This report provides a novel insight into understanding the prostate carcinogenesis.

Emerging roles for lncRNA-NEAT1 in colorectal cancer

Colorectal cancer (CRC) is the third cause of cancer death in the world that arises from the glandular and epithelial cells of the large intestine, during a series of genetic or epigenetic alternations. Recently, long non-coding RNAs (lncRNAs) has opened a separate window of research in molecular and translational medicine. Emerging evidence has supported that lncRNAs can regulate cell cycle of CRC cells. LncRNA NEAT1 has been verified to participate in colon cancer development and progression. NEAT1 as a competing endogenous RNA could suppress the expression of miRNAs, and then regulate molecules downstream of these miRNAs. In this review, we summarized emerging roles of NEAT1 in CRC cells.

Anticancer effects of melatonin via regulating lncRNA JPX-Wnt/β-catenin signalling pathway in human osteosarcoma cells

Osteosarcoma (OS) is a type of malignant primary bone cancer, which is highly aggressive and occurs more commonly in children and adolescents. Thus, novel potential drugs and therapeutic methods are urgently needed. In the present study, we aimed to elucidate the effects and mechanism of melatonin on OS cells to provide a potential treatment strategy for OS. The cell survival rate, cell viability, proliferation, migration, invasion and metastasis were examined by trypan blue assay, MTT, colony formation, wound healing, transwell invasion and attachment/detachment assay, respectively. The expression of relevant lncRNAs in OS cells was determined by real-time qPCR analysis. The functional roles of lncRNA JPX in OS cells were further examined by gain and loss of function assays. The protein expression was measured by western blot assay. Melatonin inhibited the cell viability, proliferation, migration, invasion and metastasis of OS cells (Saos-2, MG63 and U2OS) in a dose-dependent manner. Melatonin treatment significantly downregulated the expression of lncRNA JPX in Saos-2, MG63 and U2OS cells. Overexpression of lncRNA JPX into OS cell lines elevated the cell viability and proliferation, which was accompanied by the increased metastasis. We also found that melatonin inhibited the OS progression by suppressing the expression of lncRNA JPX via regulating the Wnt/β-catenin pathway. Our results suggested that melatonin inhibited the biological functions of OS cells by repressing the expression of lncRNA JPX through regulating the Wnt/β-catenin signalling pathway, which indicated that melatonin might be applied as a potentially useful and effective natural agent in the treatment of OS.

Isolation and Identification of Long Non-Coding RNAs in Exosomes Derived from the Serum of Colorectal Carcinoma Patients

Simple Summary

Treatment regimens for patients with advanced disease are limited and the mortality rate is high in these patients. A better understanding on pathogenesis and progression of cancer is critical for the development of new treatment strategies. In colorectal cancer (CRC), exosomes (secreted vesicles from cells) and long non-coding RNAs (lncRNAs) have been shown to play significant roles in disease development and progression. Long non-coding RNAs (lncRNAs) are present in the exosomes of serum and their profiles may potentially be useful as novel biomarkers for CRC patients and may provide a new insight in the pathogenesis and progression of CRC. Here, we compared the expression profiles of exosomal lncRNAs between non-cancer individuals and patients with colorectal carcinoma. The relative expression level of LINC00152 was found to be significantly lower in exosomes from sera of CRC patients as compared to non-cancer individuals whereas lncRNA H19 was significantly up-regulated in advanced-stages (stage III and IV) of CRC as compared to early-stages (stage I and II). Our data suggest that LINC00152 and H19 may play important roles in pathogenesis and progression of CRC.

Abstract

Long non-coding RNAs (lncRNAs) are non-coding RNAs consisting of more than 200 nucleotides in length. LncRNAs present in exosomes may play a critical role in the cellular processes involved in cancer pathogenesis and progression including proliferation, invasion, and migration of tumor cells. This paper aims to identify the differential expression of exosomal lncRNAs derived from the sera of non-cancer individuals and patients diagnosed with colorectal carcinoma. These differentially-expressed exosomal serum lncRNAs may provide an insight into the pathogenesis and progression of colorectal cancer (CRC). Serum exosomes and exosomes from SW480-7 cell culture supernatants were isolated and viewed by transmission electron microscope (TEM). The particle size distribution and protein markers of exosomes derived from SW480-7 were further analyzed using the Zetasizer Nano S instrument and western blotting technique. TEM showed that exosomes derived from serum and SW480-7 cells were round vesicles with sizes ranging from 50–200 nm. The exosomes derived from SW480-7 had an average diameter of 274.6 nm and contained the exosomal protein, ALIX/PDCD6IP. In our clinical studies, six lncRNAs, namely GAS5, H19, LINC00152, SNHG16, RMRP, and ZFAS1 were detected in the exosomes from sera of 18 CRC patients. Among these six lncRNAs, the expression level of LINC00152 was found to be significantly lower in CRC patients as compared to non-cancer individuals (p = 0.04) while lncRNA H19 was significantly up-regulated in advanced-stages (stage III and IV) of CRC (p = 0.04) as compared to early-stages (stage I and II). In conclusion, the detection of lower LINC00152 in exosomes of sera from CRC patients versus non-cancer individuals and H19 upregulation in advanced stages suggests that they may play important roles in pathogenesis and progression of CRC.

Current Insights and Advancements in Head and Neck Cancer: Emerging Biomarkers and Therapeutics with Cues from Single Cell and 3D Model Omics Profiling

Head and neck cancer (HNC) is among the ten leading malignancies worldwide, with India solely contributing one-third of global oral cancer cases. The current focus of all cutting-edge strategies against this global malignancy are directed towards the heterogeneous tumor microenvironment that obstructs most treatment blueprints. Subsequent to the portrayal of established information, the review details the application of single cell technology, organoids and spheroid technology in relevance to head and neck cancer and the tumor microenvironment acknowledging the resistance pattern of the heterogeneous cell population in HNC. Bioinformatic tools are used for study of differentially expressed genes and further omics data analysis. However, these tools have several challenges and limitations when analyzing single-cell gene expression data that are discussed briefly. The review further examines the omics of HNC, through comprehensive analyses of genomics, transcriptomics, proteomics, metabolomics, and epigenomics profiles. Patterns of alterations vary between patients, thus heterogeneity and molecular alterations between patients have driven the clinical significance of molecular targeted therapies. The analyses of potential molecular targets in HNC are discussed with connotation to the alteration of key pathways in HNC followed by a comprehensive study of protein kinases as novel drug targets including its ATPase and additional binding pockets, non-catalytic domains and single residues. We herein review, the therapeutic agents targeting the potential biomarkers in light of new molecular targeted therapies. In the final analysis, this review suggests that the development of improved target-specific personalized therapies can combat HNC's global plight.

lncRNA SNHG4 modulates colorectal cancer cell cycle and cell proliferation through regulating miR-590-3p/CDK1 axis

Colorectal cancer (CRC) is a prevalent malignancy worldwide. The development of genome sequencing technology has allowed the discovery that epigenetic regulation might play a critical role in CRC tumorigenesis. In the present study, we found that the long noncoding RNA (lncRNA) SNHG4 was dramatically increased in CRC tissue samples and cell lines based on both publicly available and experimental data. SNHG4 knockdown suppressed the viability and colony formation capacity of CRC cells. The expression of CDK1 was considerably increased in CRC tissue samples and cells and had a positive correlation with the expression of SNHG4 in CRC. SNHG4 silencing not only caused S phase cell cycle arrest but also significantly downregulated the CDK1, cyclin B1, and cyclin A2 protein levels in CRC cells. miR-590-3p simultaneously bound to SNHG4 and CDK1. miR-590-3p functioned to inhibit CDK1 expression. miR-590-3p overexpression exerted the same effects on the CRC cell phenotype as SNHG4 knockdown. The effects of si-SNHG4 on CRC cells were significantly reversed by anti-miR-590-3p, indicating that SNHG4 relieved the miR-590-3p-induced inhibition of CDK1 by acting as a competing endogenous RNA (ceRNA). In vivo, SNHG4 silencing inhibited subcutaneously transplanted tumor growth and decreased cell cycle marker levels, whereas miR-590-3p inhibition exerted the opposite effects. The in vivo effects of SNHG4 silencing were also reversed by miR-590-3p inhibition. The SNHG4/miR-590-3p/CDK1 axis influences the cell cycle to modulate CRC cell proliferation and subcutaneously transplanted tumor growth. Further application of this axis still requires analysis using more animal models and clinical investigations.

Involvement of Long Non-Coding RNAs in Glucose Metabolism in Cancer

The rapid and uncontrolled proliferation of cancer cells is supported by metabolic reprogramming. Altered glucose metabolism supports cancer growth and progression. Compared with normal cells, cancer cells show increased glucose uptake, aerobic glycolysis and lactate production. Byproducts of adjusted glucose metabolism provide additional benefits supporting hallmark capabilities of cancer cells. Long non-coding RNAs (lncRNAs) are a heterogeneous group of transcripts of more than 200 nucleotides in length. They regulate numerous cellular processes, primarily through physical interaction with other molecules. Dysregulated lncRNAs are involved in all hallmarks of cancer including metabolic alterations. They may upregulate metabolic enzymes, modulate the expression of oncogenic or tumor-suppressive genes and disturb metabolic signaling pathways favoring cancer progression. Thus, lncRNAs are not only potential clinical biomarkers for cancer diagnostics and prediction but also possible therapeutic targets. This review summarizes the lncRNAs involved in cancer glucose metabolism and highlights their underlying molecular mechanisms.

The lncRNA TUG1 promotes cell growth and migration in colorectal cancer via the TUG1-miR-145-5p-TRPC6 pathway

Colorectal cancer (CRC) is the third-most prevalent malignant tumor. Taurine upregulated gene 1 (TUG1), a long non-coding RNA (lncRNA), is reportedly involved in the physiological and pathological processes of CRC. However, the role of TUG1 in the progression of CRC and its underlying mechanisms are largely unknown. Here, we measured the expression of TUG1 in clinical samples from CRC patients and found that the expression level of TUG1 was higher in CRC tissues compared with the normal adjacent tissues. We then performed knockdown of TUG1 with siRNAs in two CRC cell lines and found that TUG1 knockdown inhibited the viability, proliferation, and migration of CRC cells, and reduced the ability of CRC cells to form subcutaneous tumors. Furthermore, we discovered that TUG1 affects the cellular processes in CRC cells by sponging miR-145-5p. We further found that miR-145-5p inhibits the expression of the protein-encoding gene Transient Receptor Potential Cation Channel Subfamily C Member 6 (TRPC6), and that overexpression of TRPC6 restored the inhibitory role of miR-145-5p in CRC cells. In conclusion, we have demonstrated that TUG1 exerts its role by modulating the TUG1-miR-145-5p-TRPC6 regulatory axis, thus revealing a novel molecular mechanism for the effects of TUG1 in the progression of CRC. Our data indicate that the TUG1-miR-145-5p-TRPC6 signaling pathway could serve as a target for the diagnosis and treatment of CRC.

Long non-coding RNAs in prostate tumorigenesis and therapy (Review)

Prostate cancer (PCa) is one of the most frequently diagnosed malignancy. Although there have been many advances in PCa diagnosis and therapy, the concrete mechanism remains unknown. Long non-coding RNAs (lncRNAs) are novel biomarkers associated with PCa, and their dysregulated expression is closely associated with risk stratification, diagnosis and carcinogenesis. Accumulating evidence has suggested that lncRNAs play important roles in prostate tumorigenesis through relevant pathways, such as androgen receptor interaction and PI3K/Akt. The present review systematically summarized the potential clinical utility of lncRNAs and provided a novel guide for their function in PCa.

Construction and Analysis of a ceRNA Network Reveals Potential Prognostic Markers in Colorectal Cancer

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide and is derived from an accumulation of genetic and epigenetic changes. This study explored potential prognostic markers in CRC via the construction and in-depth analysis of a competing endogenous RNA (ceRNA) network, which was generated through a three-step process. First, we screened candidate hub genes in CRC as the primary gene markers to survey their related regulatory non-coding RNAs, miRNAs. Second, the interacting miRNAs were used to search for associated lncRNAs. Thus, candidate RNAs were first constructed into ceRNA networks based on close associations with miRNAs. Further analysis at the isomiR level was also performed for each miRNA locus to understand the detailed expression patterns of the multiple variants. Finally, RNAs were performed an in-depth analysis of expression correlations, which contributed to further screening and validation of potential RNAs with close correlations to each other. Using this approach, nine hub genes, 13 related miRNAs, and 29 candidate lncRNAs were collected and used to construct the ceRNA network. Further in-depth analysis identified the MFAP5-miR-200b-3p-AC005154.6 axis as a potential prognostic marker in CRC. MFAP5 and miR-200b-3p have previously been reported to play important roles in tumorigenesis. These RNAs showed potential prognostic values, and the combination of them may have more sensitivity than using them alone. In conclusion, MFAP5, miR-200b-3p, and AC005154.6 may have potential prognostic value in CRC and may provide a prognostic reference for this patient population.

A health disparities study of MicroRNA-146a expression in prostate cancer samples derived from African American and European American patients

Considering the prevalence of prostate cancer all over the world, it is desired to have tools, technologies, and biomarkers which help in early detection of the disease and discriminate different races and ethnic groups. Genetic information from the single gene analysis and genome-wide association studies have identified few biomarkers, however, the drivers of prostate cancer remain unknown in the majority of prostate cancer patients. In those cases where genetic association has been identified, the genes confer only a modest risk of this cancer, hence, making them less relevant for risk counseling and disease management. There is a need for additional biomarkers for diagnosis and prognosis of prostate cancer. MicroRNAs are a class of non-protein coding RNA molecules that are frequently dysregulated in different cancers including prostate cancer and show promise as diagnostic biomarkers and targets for therapy. Here we describe the role of micro RNA 146a (miR-146a) which may serve as a diagnostic and prognostic marker for prostate cancer, as indicated from the data presented in this report. Also, a pilot study indicated differential expression of miR-146a in prostate cancer cell lines and tissues from different racial groups. Reduced expression of miR-146a was observed in African American tumor tissues compared to those from European Whites This report provides a novel insight into understanding the prostate carcinogenesis.

Silencing of Long Noncoding RNA LINC00346 Inhibits the Tumorigenesis of Colorectal Cancer Through Targeting MicroRNA-148b

PURPOSE

This study was aimed to explore the regulatory effect of long noncoding RNA LINC00346 (LINC00346) on colorectal cancer (CRC) and the potential molecular mechanisms.

METHODS

The expression of LINC00346 and microRNA-148b (miR-148b) in CRC tissues and cells was detected by qRT-PCR. LINC00346 was overexpressed and silenced in HT29 and HCT116 cells by the transfection of pcDNA-LINC00346 and si-LINC00346, respectively. The cell proliferation, migration, invasion, and apoptosis were analyzed by cell counting kit-8 (CCK-8), wound-healing, transwell, and flow cytometry assay, respectively. The targeting relationship between LINC00346 and miR-148b was predicted by TargetScan and determined by dual-luciferase reporter assay. A tumor xenograft model was established in mice to evaluate the tumor growth in vivo.

RESULTS

The expression of LINC00346 was up-regulated in CRC tissues and cells. The expression of LINC00346 was positively associated with the TNM stage, lymphoma metastasis and histological grade. Overexpression of LINC00346 promoted the proliferation, migration and invasion and inhibited the apoptosis of HT29 and HCT116 cells. MiR-148b was a target of LINC00346. Silencing of miR-148b reversed the anti-tumor effect of si-LINC00346 on CRC cells. Furthermore, silencing of LINC00346 inhibited the tumor growth in mice through up-regulating miR-148b.

CONCLUSION

Silencing of LINC00346 inhibited the proliferation, migration and invasion, and promoted the apoptosis of CRC cells through targeting miR-148b.

Loss of Tenascin-X expression during tumor progression: A new pan-cancer marker

Cancer is a systemic disease involving multiple components produced from both tumor cells themselves and surrounding stromal cells. The pro- or anti-tumoral role of the stroma is still under debate. Indeed, it has long been considered the main physical barrier to the diffusion of chemotherapy by its dense and fibrous nature and its poor vascularization. However, in murine models, the depletion of fibroblasts, the main ExtraCellular Matrix (ECM)-producing cells, led to more aggressive tumors even though they were more susceptible to anti-angiogenic and immuno-modulators. Tenascin-C (TNC) is a multifunctional matricellular glycoprotein (i.e. an ECM protein also able to induce signaling pathway) and is considered as a marker of tumor expansion and metastasis. However, the status of other tenascin (TN) family members and particularly Tenascin-X (TNX) has been far less studied during this pathological process and is still controversial. Herein, through (1) in silico analyses of the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases and (2) immunohistochemistry staining of Tissue MicroArrays (TMA), we performed a large and extensive study of TNX expression at both mRNA and protein levels (1) in the 6 cancers with the highest incidence and mortality in the world (i.e. lung, breast, colorectal, prostate, stomach and liver) and (2) in the cancers for which sparse data regarding TNX expression already exist in the literature. We thus demonstrated that, in most cancers, TNX expression is significantly downregulated during cancer progression and we also highlighted, when data were available, that high TNXB mRNA expression in cancer is correlated with a good survival prognosis.

LINC00858 promotes colorectal cancer by sponging miR-4766-5p to regulate PAK2

OBJECTIVES

LncRNAs (long noncoding RNAs) have been reported to critically regulate colorectal cancer (CRC). We prospectively investigated effects and mechanisms of lncRNA LINC00858 on regulation of CRC progression.

METHODS

Expression of LINC00858 and its target were analyzed by quantitative real-time polymerase chain reaction and in situ hybridization. MTT and bromodeoxyuridine/5-bromo-2'-deoxyuridine (BrdU) staining to assess cell proliferation ability. Flow cytometry, wound healing, and transwell assays were conducted to evaluate cell apoptosis, migration, and invasion, respectively. Interaction between LINC00858 and its target was confirmed by luciferase activity assay and RNA immunoprecipitation. Subcutaneous xenotransplanted tumor model was established and employed to detect tumorigenic functions of LINC00858, and further evaluated by qRT-PCR, western blot, immunohistochemistry, and hematoxylin and eosin staining.

RESULTS

With a predicted poor prognosis, LINC00858 was upregulated in CRC patients. LINC00858 knockdown suppressed cell proliferation, invasion, and migration abilities, meanwhile induced cell apoptosis. Moreover, LINC00858 could target and inhibit the miR-4766-5p expression, thus promoting CRC progression. miR-4766-5p further suppressed serine/threonine kinase PAK2. Interestingly, interference of LINC00858 suppressed tumorigenic ability of CRC in vivo by downregulating PAK2.

CONCLUSIONS

LINC00858 promoted CRC progression by sponging miR-4766 to upregulate PAK2, shedding lights on LINC00858 as a potential therapeutic target candidate in CRC treatment from bench to clinic.

LncRNA RP11-361F15.2 promotes osteosarcoma tumorigenesis by inhibiting M2-Like polarization of tumor-associated macrophages of CPEB4

Long non-coding RNAs (lncRNAs) regulates the initiation and progression of osteosarcoma (OS), specifically lncRNA RP11-361F15.2 has been shown to play prominent roles in tumorigenesis. Previously, M2-Like polarization of tumor-associated macrophages (TAMs) has been identified to play a key role in cancer migration/invasion. Hence, it is essential to understand the role of RP11-361F15.2 in tumorigenesis and its association with M2-Like polarization of TAMs. The results indicate that RP11-361F15.2 is significantly increased in OS tissues, and its expression is positively correlated with cytoplasmic polyadenylation element binding protein 4 (CPEB4) expression and negatively associated with miR-30c-5p expression. Further, overexpression of RP11-361F15.2 increased OS cell migration/invasion and M2-Like polarization of TAMs in vitro, as well as promoted xenograft tumor growth in vivo. Mechanistically, luciferase reporter assays indicated that RP11-361F15.2 upregulated CPEB4 expression by competitively binding to miR-30c-5p. Further, we have identified that RP11-361F15.2 promotes CPEB4-mediated tumorigenesis and M2-Like polarization of TAMs through miR-30c-5p in OS. We also identified that RP11-361F15.2 acts as competitive endogenous RNA (ceRNA) against miR-30c-5p thereby binding and activating CPEB4. This RP11-361F15.2/miR-30c-5p/CPEB4 loop could be used as a potential therapeutic strategy for the treatment of OS.

Adipose tissue gene expression of long non-coding RNAs; MALAT1, TUG1 in obesity: is it associated with metabolic profile and lipid homeostasis-related genes expression?

BACKGROUND

Recent studies point toward the possible regulatory roles of two lncRNAs; metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and taurine upregulated gene 1 (TUG1) in the pathogenesis of obesity-related disorders and regulation of lipogenesis and adipogenesis. In an attempt to understand the molecules involved in human obesity pathogenesis, we aimed to evaluate the expression of MALAT1 and TUG1 in visceral adipose tissues (VAT) and subcutaneous adipose tissues (SAT) of obese women, as compared to normal-weight women. The mRNA expression of possible target genes including peroxisome proliferator-activated receptor gamma (PPARγ), PPARγ coactivator-1 alpha (PGC1α), sterol regulatory element-binding protein-1c (SREBP-1c), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) which are involved in adipogenesis and lipogenesis were also examined.

METHODS

This study was conducted on 20 obese [body mass index (BMI) ≥ 30 kg/m 2] female participants and 19 normal-weight (BMI < 25 kg/m 2) female participants. Real-time PCR was performed to investigate the mRNA expression of the above-mentioned genes in VAT and SAT from all participants.

RESULTS

The results showed lower mRNA levels of TUG1 in both the VAT and SAT of obese women, compared to normal-weight women. Furthermore, TUG1 expression in SAT positively correlated with BMI, waist circumference (WC), hip circumference, HOMA-IR, and insulin levels, eGFR value, creatinine levels, and hs-CRP in all participants independent of age and HOMA-IR. However, VAT mRNA expression of TUG1 had a positive correlation with obesity indices and HOMA-IR and insulin levels in the whole population. Moreover, SAT mRNA level of TUG1 was positively correlated with SAT gene expression of PGC1α, SREBP-1c, FAS, and ACC independent of age and HOMA-IR. Although mRNA expression of MALAT1 did not differ between two groups for any tissue, it was positively correlated with SAT mRNA levels of SREBP-1c, PPARγ, and their targets; FAS and ACC, as well as with VAT mRNA levels of PGC1α.

CONCLUSIONS

It seems likely that TUG1 with distinct expression pattern in VAT and SAT are involved in the regulation of lipogenic and adipogenic genes and obesity-related parameters. However, more studies are necessary to establish this concept.

Diagnostic and prognostic potential of tissue and circulating long non-coding RNAs in colorectal tumors

Long non-coding RNAs (lncRNAs) are members of the non-protein coding RNA family longer than 200 nucleotides. They participate in the regulation of gene and protein expression influencing apoptosis, cell proliferation and immune responses, thereby playing a critical role in the development and progression of various cancers, including colorectal cancer (CRC). As CRC is one of the most frequently diagnosed malignancies worldwide with high mortality, its screening and early detection are crucial, so the identification of disease-specific biomarkers is necessary. LncRNAs are promising candidates as they are involved in carcinogenesis, and certain lncRNAs (e.g., CCAT1, CRNDE, CRCAL1-4) show altered expression in adenomas, making them potential early diagnostic markers. In addition to being useful as tissue-specific markers, analysis of circulating lncRNAs (e.g., CCAT1, CCAT2, BLACAT1, CRNDE, NEAT1, UCA1) in peripheral blood offers the possibility to establish minimally invasive, liquid biopsy-based diagnostic tests. This review article aims to describe the origin, structure, and functions of lncRNAs and to discuss their contribution to CRC development. Moreover, our purpose is to summarise lncRNAs showing altered expression levels during tumor formation in both colon tissue and plasma/serum samples and to demonstrate their clinical implications as diagnostic or prognostic biomarkers for CRC.

LncRNA ADAMTS9-AS2 inhibits cell proliferation and decreases chemoresistance in clear cell renal cell carcinoma via the miR-27a-3p/FOXO1 axis

Accumulating evidence reveals the principal role of long noncoding RNAs in the progression of clear cell renal cell carcinoma (ccRCC). However, little is known about the underlying mechanism of ADAM metallopeptidase with thrombospondin type 1 motif, 9 antisense RNA 2 (ADAMTS9-AS2) in ccRCC. Here, bioinformatics analyses verified ADAMTS9-AS2 is a long noncoding RNA and its high expression was associated with better prognosis of ccRCC. ADAMTS9-AS2 was clearly downregulated in ccRCC clinical samples and cell lines. Clinical data showed low-expressed ADAMTS9-AS2 was correlated with worse overall survival in ccRCC patients. Next, miR-27a-3p was identified as an inhibitory target of ADAMTS9-AS2 by dual-luciferase reporter and RNA immunoprecipitation assays. Both overexpressed ADAMTS9-AS2 and underexpressed miR-27a-3p in ccRCC cell lines led to the inhibition of cell proliferation and the reduction of chemoresistance. Additionally, Forkhead Box Protein O1 (FOXO1) was confirmed as the inhibitory target of miR-27a-3p. Induced by ADAMTS9-AS2 overexpression, cell proliferation and chemoresistance exhibited an obvious reduction, FOXO1 expression showed an evident increase, but all were reversed after miR-27a-3p was simultaneously overexpressed. Collectively, these results suggest ADAMTS9-AS2 inhibits the progression and impairs the chemoresistance of ccRCC via miR-27a-3p-mediated regulation of FOXO1 and may serve as a prognostic biomarker and therapeutic target for ccRCC.

Long non-coding RNA LINC00858 promotes cells proliferation, migration and invasion by acting as a ceRNA of miR-22-3p in colorectal cancer

Though long non-coding RNA LINC00858 (LINC00858) has been shown to be involved in tumours of other tissues, its involvement in colorectal cancer (CRC) is still unknown. We aimed to investigated expression and mechanism LINC00858 in human CRC. In this study, we firstly found that LINC00858 expression was significantly up-regulated in both CRC tissues and cell lines by both online data and RT-PCR assay. Then, clinical assay revealed that high LINC00858 expression was significantly associated with advanced clinical progression and poor prognosis. Multivariate analysis demonstrated that high LINC00858 expression was an independent poor prognostic factor for CRC patients. Moreover, lost-of-function assay indicated that knockdown of LINC00858 suppressed CRC cells proliferation, migration and invasion, and promoted apoptosis. Mechanistically, bioinformatics analysis, dual-luciferase reporter assays, and western blot assays showed that LINC00858 functioned as competing endogenous RNA to repress miR-22-3p, which controlled its down-stream target YWHAZ. Then, we suggested that LINC00858 exerted its function through the miR-22-3p/YWHAZ axis. To our knowledge, this is the first report which showed the role of LINC00858 in the progression of CRC. Our findings indicated that LINC00858 played an important role in CRC, and may serve as a novel prognostic factor and therapeutic target.

Roles of long non-coding RNAs in colorectal cancer tumorigenesis: A Review

Long non-coding RNAs (lncRNAs) are newly identified potential biological and gene regulators. Similar to other cell-free circulating cancer-related nucleic acids, lncRNAs are released in the peripheral circulation of cancer patients and allow for non-invasive gene expression assessment. lncRNAs are considered to be promising biomarkers for cancer prognosis and diagnosis. Several lncRNAs have been found to regulate developmental processes in a number of biological disorders. Recent studies indicated that lncRNAs are associated with numerous diseases, most notably cancer, as they were found to be highly expressed or silenced in a number of human cancers, including colorectal cancer (CRC). Despite advances in the current detection methods, over half of cancer patients succumb to the disease, as several CRC cases are diagnosed at an advanced stage. Due to the lack of non-invasive and low-cost prognostic and diagnostic tests for CRC, the identification of novel, potentially effective biomarkers has been attracting increasing attention in recent cancer research. The present review focused on the most widely applied lncRNAs in cancer detection, including CRC, in vitro.

LncRNAs with miRNAs in regulation of gastric, liver, and colorectal cancers: updates in recent years

Long noncoding RNA (lncRNA) is a kind of RNAi molecule composed of hundreds to thousands of nucleotides. There are several major types of functional lncRNAs which participate in some important cellular pathways. LncRNA-RNA interaction controls mRNA translation and degradation or serves as a microRNA (miRNA) sponge for silencing. LncRNA-protein interaction regulates protein activity in transcriptional activation and silencing. LncRNA guide, decoy, and scaffold regulate transcription regulators of enhancer or repressor region of the coding genes for alteration of expression. LncRNA plays a role in cellular responses including the following activities: regulation of chromatin structural modification and gene expression for epigenetic and cell function control, promotion of hematopoiesis and maturation of immunity, cell programming in stem cell and somatic cell development, modulation of pathogen infection, switching glycolysis and lipid metabolism, and initiation of autoimmune diseases. LncRNA, together with miRNA, are considered the critical elements in cancer development. It has been demonstrated that tumorigenesis could be driven by homeostatic imbalance of lncRNA/miRNA/cancer regulatory factors resulting in biochemical and physiological alterations inside the cells. Cancer-driven lncRNAs with other cellular RNAs, epigenetic modulators, or protein effectors may change gene expression level and affect the viability, immortality, and motility of the cells that facilitate cancer cell cycle rearrangement, angiogenesis, proliferation, and metastasis. Molecular medicine will be the future trend for development. LncRNA/miRNA could be one of the potential candidates in this category. Continuous studies in lncRNA functional discrepancy between cancer cells and normal cells and regional and rational genetic differences of lncRNA profiles are critical for clinical research which is beneficial for clinical practice.

LncRNA LINC01305 silencing inhibits cell epithelial-mesenchymal transition in cervical cancer by inhibiting TNXB-mediated PI3K/Akt signalling pathway

Cervical cancer (CC) remains one of the leading malignancies afflicting females worldwide, with its aetiology associated with long‐term papillomavirus infection. Recent studies have shifted their focus and research attention to the relationship between long non‐coding RNAs (lncRNAs) and CC therapeutic. Thus, the aim of the current study was to investigate the underlying mechanism of lncRNA LINC01305 on the cell invasion, migration and epithelial‐mesenchymal transition (EMT) of CC cells via modulation of the PI3K/Akt signalling pathway by targeting tenascin‐X B (TNXB). The expressions of LINC01305, TNXB, MMP2, MMP9, E‐cadherin, vimentin, PI3K, Akt, p‐PI3K, p‐Akt and TNXB were detected in this study. After which, the cell invasion and migration abilities of the CC cells were determined respectively. Bioinformatics and the application of a dual luciferase reporter gene assay provided verification indicating that TNXB is the target gene of lncRNA LINC01305. Reverse transcription quantitative polymerase chain reaction (RT‐qPCR) and western blot analysis methods revealed that the expressions of MMP2, MMP9, vimentin, PI3K, Akt, p‐PI3K and p‐Akt were decreased following the down‐regulation of LncRNA LINC01305 or overexpression of TNXB. LncRNA LINC01305 silencing or TNXB overexpression was noted to decrease the migration and invasion of SiHa cells. Taken together, the key findings of the current study present evidence suggesting that lncRNA LINC01305 silencing suppresses EMT, invasion and migration via repressing the PI3K/Akt signalling pathway by means of targeting TNXB in CC cells, which ultimately provides novel insight and identification of potential therapeutic targets for CC.

Long noncoding RNA HAGLROS regulates apoptosis and autophagy in colorectal cancer cells via sponging miR-100 to target ATG5 expression

The aim of this study was to explore the relationship between the expression of HOXD antisense growth-associated long noncoding RNA (HAGLROS) and prognosis of patients with colorectal cancer (CRC), as well as the roles and regulatory mechanism of HAGLROS in CRC development. The HAGLROS expression in CRC tissues and cells was detected. The correlation between HAGLROS expression and survival time of CRC patients was investigated. Moreover, HAGLROS was overexpressed and suppressed in HCT-116 cells, followed by detection of cell viability, apoptosis, and the expression of apoptosis-related proteins and autophagy markers. Furthermore, the association between HAGLROS and miR-100 and the potential targets of miR-100 were investigated. Besides, the regulatory relationship between HAGLROS and PI3K/AKT/mTOR pathway was elucidated. The results showed that HAGLROS was highly expressed in CRC tissues and cells. Highly expression of HAGLROS correlated with a shorter survival time of CRC patients. Moreover, knockdown of HAGLROS in HCT-116 cells induced apoptosis by increasing the expression of Bax/Bcl-2 ratio, cleaved-caspase-3, and cleaved-caspase-9, and inhibited autophagy by decreasing the expression of LC3II/LC3I and Beclin-1 and increasing P62 expression. Furthermore, HAGLROS negatively regulated the expression of miR-100, and HAGLROS controlled HCT-116 cell apoptosis and autophagy through negatively regulation of miR-100. Autophagy related 5 (ATG5) was verified as a functional target of miR-100 and miR-100 regulated HCT-116 cell apoptosis and autophagy through targeting ATG5. Besides, HAGLROS overexpression activated phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway. In conclusion, a highly expression of HAGLROS correlated with shorter survival time of CRC patients. Downregulation of HAGLROS may induce apoptosis and inhibit autophagy in CRC cells by regulation of miR-100/ATG5 axis and PI3K/AKT/mTOR pathway.

Overexpression of long noncoding RNA NORAD in colorectal cancer associates with tumor progression

Purpose

The aim of this study was to elucidate the role and clinical significance of long noncoding RNA-activated by DNA damage (NORAD) in colorectal cancer (CRC).

Methods

Sixty pairs of tumorous and adjacent nontumorous tissues derived from CRC patients were subjected to quantitative real-time polymerase chain reaction to determine the expression level of NORAD. The serum levels of NORAD expression were also measured in an independent cohort of CRC patients as well as patients with benign diseases and healthy controls. Comparative analyses were performed to investigate the relationships between NORAD levels in tissues and clinicopathological features of CRC. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic value of NORAD in patients with CRC. Furthermore, the potential functions of NORAD in the development of CRC were explored in vitro, using the HCT116 and SW1116 CRC cell lines.

Result

NORAD expression was significantly upregulated in the tumorous tissues of CRC patients (P<0.001) compared to the adjacent nontumorous tissues. Higher NORAD expression was associated with advanced CRC. Moreover, serum levels supported that NORAD could distinguish CRC patients from healthy controls and patients with benign diseases, indicating a potential diagnostic role in CRC. The ROC curve analysis showed a diagnostic efficacy with area under the curve of 0.800 (95% CI: 0.737–0.853). Mechanistic investigations indicated that NORAD silencing reduced CRC cell proliferation, migration, and invasion.

Conclusion

NORAD may serve as a novel predictor in CRC and may be a potential target for future therapy.

LINC00473 promotes the Taxol resistance via miR-15a in colorectal cancer

Dysregulation of long non-coding RNAs (LncRNAs) participated into the initiation and progression of different diseases via direct regulation of proteins or indirect regulation of microRNA (miRNA)-target genes. LINC00473 is a novel carcinoma-related LncRNA and up-regulated in many cancers for tumor growth and metastasis, but its role in chemotherapy resistance is unclear. We here investigated the function of LINC00473 in colorectal cancer (CRC) in vitro and in vivo The CRC tissues (n=20) and relative normal tissues were collected and found that LINC00473 was overexpressed in CRC tissues when compared with which in normal tissues. Highly expressed LINC00473 predicted large tumor size, high TNM stage of CRC patients. Interestingly, the tumor suppressor miR-15a was down-regulated and negatively correlated with LINC00473 levels in CRC. LINC00473 harbored the binding sites for miR-15a and reduced its availability in CRC cell line HCT116. Knockdown of LINC00473 elevated the expression of miR-15a. Moreover, in the Taxol-resistant HCT116, the LINC00473 level was further increased than that in HCT116. Knockdown of LINC00473 restored the Taxol-induced cytotoxicity, inhibited the cell vitality, colony formation and induced apoptosis, impaired the ability of migration or invasion, but these effects could be abrogated by the inhibition of miR-15a. Mechanistically, the BCL-2-related anti-apoptosis pathway was activated and the multidrug-resistant (MDR) genes LRP, MDR1 were up-regulated by LINC00473. Furthermore, inhibition of LINC00473 in vivo could overcome the Taxol resistance of CRC cells, could recover the expression of tumor suppressor miR-15a and chemotherapy-induced tumor regression, indicating that LINC00473 functioned as oncogene in CRC via miR-15a.

Profiles of alternative splicing in colorectal cancer and their clinical significance: A study based on large-scale sequencing data

Background

Alternative splicing (AS), as a potent and pervasive mechanism of transcriptional regulatory, expands the genome's coding capacity and involves in the initiation and progression of cancer. Systematic analysis of alternative splicing in colorectal cancer (CRC) is lacking and greatly needed.

Methods

RNA-Seq data and corresponding clinical information of CRC cohort were downloaded from the TCGA data portal. Then, a java application, known as SpliceSeq, was used to evaluate the RNA splicing patterns and calculate the Percent Spliced In (PSI) value. Differently expressed AS events (DEAS) were identified based on PSI value between paired CRC and adjacent tissues. DEAS and its splicing networks were further analyzed by bioinformatics methods. Kaplan-Meier, Cox proportional regression and unsupervised clustering analysis were used to evaluate the association between DEAS and patients' clinical features.

Results

After strict filtering, a total of 34,334 AS events were identified, among which 421 AS events were found expressed differently. Parent genes of these DEAS play a important role in regulating CRC-related processes such as protein kinase activity (FDR<0.0001), PI3K-Akt signaling pathway (FDR = 0.0024) and p53 signaling pathway (FDR = 0.0143). 37 DEAS events were found to be associated with OS, and 68 DEAS events were found to be associated with DFS. Stratifying patients according to the PSI value of AT in CXCL12 and RI in CSTF3 formed significant Kaplan-Meier curves in both OS and DFS survival analysis. Unsupervised clustering analysis using DEAS revealed four clusters with distinct survival patterns, and associated with consensus molecular subtypes.

Conclusions

Large differences of AS events in CRC appear to exist, and these differences are likely to be important determinants of both prognosis and biological regulation. Our identified CRC-related AS events and uncovered splicing networks are valuable in deciphering the underlying mechanisms of AS in CRC, and provide clues of therapeutic targets to further validations.

Long Non-Coding RNAs in Multifactorial Diseases: Another Layer of Complexity

Multifactorial diseases such as cancer, cardiovascular conditions and neurological, immunological and metabolic disorders are a group of diseases caused by the combination of genetic and environmental factors. High-throughput RNA sequencing (RNA-seq) technologies have revealed that less than 2% of the genome corresponds to protein-coding genes, although most of the human genome is transcribed. The other transcripts include a large variety of non-coding RNAs (ncRNAs), and the continuous generation of RNA-seq data shows that ncRNAs are strongly deregulated and may be important players in pathological processes. A specific class of ncRNAs, the long non-coding RNAs (lncRNAs), has been intensively studied in human diseases. For clinical purposes, lncRNAs may have advantages mainly because of their specificity and differential expression patterns, as well as their ideal qualities for diagnosis and therapeutics. Multifactorial diseases are the major cause of death worldwide and many aspects of their development are not fully understood. Recent data about lncRNAs has improved our knowledge and helped risk assessment and prognosis of these pathologies. This review summarizes the involvement of some lncRNAs in the most common multifactorial diseases, with a focus on those with published functional data.

Non-coding RNAs, the Trojan horse in two-way communication between tumor and stroma in colorectal and hepatocellular carcinoma

In a continuous and mutual exchange of information, cancer cells are invariably exposed to microenvironment transformation. This continuous alteration of the genetic, molecular and cellular peritumoral stroma background has become as critical as the management of primary tumor progression events in cancer cells. The communication between stroma and tumor cells within the extracellular matrix is one of the triggers in colon and liver carcinogenesis. All non- codingRNAs including long non-coding RNAs, microRNAs and ultraconserved genes play a critical role in almost all cancers and are responsible for the modulation of the tumor microenvironment in several malignant processes such as initiation, progression and dissemination. This review details the involvement of non codingRNAs in the evolution of human colorectal carcinoma and hepatocellular carcinoma in relationship with the microenvironment. Recent research has shown that a considerable number of dysregulated non- codingRNAs could be valuable diagnostic and prognostic biomarkers in cancer. Therefore, more in-depth knowledge of the role non- codingRNAs play in stroma-tumor communication and of the complex regulatory mechanisms between ultraconserved genes and microRNAs supports the validation of future effective therapeutic targets in patients suffering from hepatocellular and colorectal carcinoma, two distinctive entities which share quite a lot common non-coding RNAs.

The Role of Long Non-Coding RNAs in Osteosarcoma

Long non-coding RNAs (lncRNAs) constitute non-protein coding transcripts with a size > than 200 nucleotides. They are involved in many cellular processes, such as chromatin remodelling, transcription, and gene expression. They play a role in the development, progression, and invasion of many human cancers, including osteosarcoma. This rare tumor entity predominantly arises in children and young adults. Treatment consists of polychemotherapy and surgical resection, increasing survival rates up to 60%. In the present review, the role of lncRNAs with prognostic, predictive, therapeutic, and diagnostic significance in osteosarcoma is discussed. Moreover, their potential application in clinical practice is highlighted.

To Wnt or Lose: The Missing Non-Coding Linc in Colorectal Cancer

Colorectal cancer (CRC) is the third most frequent cancer and one of the leading causes for cancer-related mortality. Aberrant activation of the Wnt signaling is an essential initiating factor in colon carcinogenesis, and a driving force of CRC progression. Recently, long non-coding RNAs (lncRNAs) have emerged as significant players in CRC pathogenesis through diversified mechanisms. Although both Wnt signaling and lncRNAs represent interesting research areas for CRC, an effort of directly connecting these two areas is lacking. To fill in the knowledge gap, we focus on the reported findings of lncRNAs that regulate Wnt signaling or essential Wnt signaling targets. These include several newly discovered lncRNAs originated from the amplified cancer-associated chromosome 8q24 region that surrounds the essential Wnt target MYC gene, lncRNAs reported to be involved in CRC stem cells, and several individual lncRNAs connected to Wnt signaling through other mechanisms. This review will provide essential information that assists in understanding the missing link of lncRNAs to the classical Wnt signaling in CRC.

An integrated lncRNA, microRNA and mRNA signature to improve prognosis prediction of colorectal cancer

Although the outcome of patients with colorectal cancer (CRC) has improved significantly, prognosis evaluation still presents challenges due to the disease heterogeneity. Increasing evidences revealed the close correlation between aberrant expression of certain RNAs and the prognosis. We envisioned that combined multiple types of RNAs into a single classifier could improve postoperative risk classification and add prognostic value to the current stage system. Firstly, differentially expressed RNAs including mRNAs, miRNAs and lncRNAs were identified by two different algorithms. Then survival and LASSO analysis was conducted to screen survival-related DERs and build a multi-RNA-based classifier for CRC patient stratification. The prognostic value of the classifier was self-validated in the TCGA CRC cohort and further validated in an external independent set. Finally, survival receiver operating characteristic analysis was used to assess the performance of prognostic prediction. We found that the multi-RNA-based classifier consisted by 12 mRNAs, 1miRNA and 1 lncRNA, which could divide the patients into high and low risk groups with significantly different overall survival (training set: HR 2.54, 95%CI 1.67-3.87, p<0.0001; internal testing set: HR 2.54, 95%CI 1.67-3.87, p<0.0001; validation set: HR 5.02, 95% CI 2.2–11.6; p=0·0002). In addition, the classifier is not only independent of clinical features but also with a similar prognostic ability to the well-established TNM stage (AUC of ROC 0.83 versus 0.74, 95% CI = 0.608-0.824, P =0.0878). Furthermore, combination of the multi-RNA-based classifier with clinical features was a more powerful predictor of prognosis than either of the two parameters alone. In conclusion, the multi-RNA-based classifier may have important clinical implications in the selection of patients with CRC who are at high risk of mortality and add prognostic value to the current stage system.

Knockdown of lncRNA HNF1A-AS1 inhibits oncogenic phenotypes in colorectal carcinoma

Long non-coding RNAs (lncRNAs) have been demonstrated to serve important roles in the development and progression of cancer. Recently HNF1A antisense RNA 1 (HNF1A‑AS1), a lncRNA, has been reported as exhibiting a potential oncogenic role in the development of many types of cancer. However, the expression and the role of HNF1A‑AS1 in colorectal carcinoma (CRC) remains unclear. In the present study, the role of HNF1A‑AS1 in CRC was examined for the first time and its correlation with CRC cell biological behaviors was analyzed. The results demonstrated that HNF1A‑AS1 was distinctly upregulated in CRC tissues and associated with CRC metastasis to the lymph nodes. Reverse transcription‑quantitative polymerase chain reaction revealed that HNF1A‑AS1 was also upregulated in CRC cell lines and localized in the nucleus. In addition, knockdown of HNF1A‑AS1 expression notably inhibited CRC cell proliferation, migration, invasion and colony formation, and suppressed S‑phase entry in vitro. Taken together, these results suggested that HNF1A‑AS1 might serve as a promising prognostic marker for CRC tumorigenesis and progression.

Involvement of Non-coding RNAs in the Signaling Pathways of Colorectal Cancer

Colorectal cancer (CRC) is one of the most common diagnosed cancers worldwide. The metastasis and development of resistance to anti-cancer treatment are major challenges in the treatment of CRC. Understanding mechanisms underpinning the pathogenesis is therefore critical in developing novel agents for CRC treatments. A large number of evidence has demonstrated that non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs have functional roles in both the physiological and pathological processes by regulating the expression of their target genes. These molecules are engaged in the pathobiology of neoplastic diseases and are targets for the diagnosis, prognosis and therapy of a variety of cancers, including CRC. In this regard, ncRNAs have emerged as one of the hallmarks of CRC pathogenesis and they also play key roles in metastasis, drug resistance and the stemness of CRC stem cell by regulating various signaling networks. Therefore, a better understanding the ncRNAs involved in the signaling pathways of CRC may lead to the development of novel strategy for diagnosis, prognosis and treatment of CRC. In this chapter, we summarize the latest findings on ncRNAs, with a focus on miRNAs and lncRNAs involving in signaling networks and in the regulation of pathogenic signaling pathways in CRC.

Knockdown of Long Noncoding RNA GHET1 Inhibits Cell Proliferation and Invasion of Colorectal Cancer

Emerging evidence has identified the vital role of long noncoding RNAs (lncRNAs) in the development of colorectal cancer. In this study, we aimed to investigate the role of lncRNA gastric carcinoma highly expressed transcript 1 (GHET1) in colorectal cancer. We analyzed the expression of GHET1 in colorectal cancer (CRC) tissues by using ISH. We found that GHET1 expression was significantly increased in the CRC samples compared with adjacent tissues. Furthermore, the cancer tissues had higher GHET1 mRNA levels than their matched adjacent tissues. GHET1 expression was also significantly increased in the CRC cell lines compared with human normal colon epithelial cells. Downregulation of GHET1 mediated by shRNA suppressed the proliferation, cell cycle arrest, migration, and invasion of colorectal cancer cells in vitro. In addition, inhibition of GHET1 reversed the epithelial–mesenchymal transition in colorectal cancer cell lines. Taken together, our results suggest the potential use of GHET1 as a therapeutic target of colorectal cancer.

Current Insights into Long Non-Coding RNAs (LncRNAs) in Prostate Cancer

The importance of long non-coding RNAs (lncRNAs) in the pathogenesis of various malignancies has been uncovered over the last few years. Their dysregulation often contributes to or is a result of tumour progression. In prostate cancer, the most common malignancy in men, lncRNAs can promote castration resistance, cell proliferation, invasion, and metastatic spread. Expression patterns of lncRNAs often change during tumour progression; their expression levels may constantly rise (e.g., HOX transcript antisense RNA, HOTAIR), or steadily decrease (e.g., downregulated RNA in cancer, DRAIC). In prostate cancer, lncRNAs likewise have diagnostic (e.g., prostate cancer antigen 3, PCA3), prognostic (e.g., second chromosome locus associated with prostate-1, SChLAP1), and predictive (e.g., metastasis-associated lung adenocarcinoma transcript-1, MALAT-1) functions. Considering their dynamic role in prostate cancer, lncRNAs may also serve as therapeutic targets, helping to prevent development of castration resistance, maintain stable disease, and prohibit metastatic spread.

Current Status of Long Non-Coding RNAs in Human Breast Cancer

Breast cancer represents a major health burden in Europe and North America, as recently published data report breast cancer as the second leading cause of cancer related death in women worldwide. Breast cancer is regarded as a highly heterogeneous disease in terms of clinical course and biological behavior and can be divided into several molecular subtypes, with different prognosis and treatment responses. The discovery of numerous non-coding RNAs has dramatically changed our understanding of cell biology, especially the pathophysiology of cancer. Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts >200 nucleotides in length. Several studies have demonstrated their role as key regulators of gene expression, cell biology and carcinogenesis. Deregulated expression levels of lncRNAs have been observed in various types of cancers including breast cancer. lncRNAs are involved in cancer initiation, progression, and metastases. In this review, we summarize the recent literature to highlight the current status of this class of long non-coding lncRNAs in breast cancer.

Circulating long noncoding RNAs as novel biomarkers of human diseases

Long noncoding RNAs (lncRNAs) are a kind of noncoding RNAs which are longer than ˜200 nucleotides, lacking of protein-encoding capacity and are implicated in the pathogenesis of various diseases. Recently, it was demonstrated that lncRNAs could be released into the circulation and be stable in blood. Circulating lncRNAs have been reported to have potential in distinguishing patients from healthy individuals. Therefore, the detection of circulating lncRNAs may be valuable for improving the diagnosis and prognosis of various diseases. This review summarized the current understanding of circulating lncRNAs as novel biomarkers of various human diseases, such as cancer, cardiovascular diseases, nervous system diseases and other diseases, which highlighted the significance of circulating lncRNAs as novel diagnostic and prognostic biomarkers of human diseases.

Current Insights into Long Non-Coding RNAs in Renal Cell Carcinoma

Renal cell carcinoma (RCC) represents a deadly disease with rising mortality despite intensive therapeutic efforts. It comprises several subtypes in terms of distinct histopathological features and different clinical presentations. Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts in the genome which vary in expression levels and length and perform diverse functions. They are involved in the inititation, evolution and progression of primary cancer, as well as in the development and spread of metastases. Recently, several lncRNAs were described in RCC. This review emphasises the rising importance of lncRNAs in RCC. Moreover, it provides an outlook on their therapeutic potential in the future.

Long Non-Coding RNAs As Potential Novel Prognostic Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is the fourth most common cause of death worldwide. Surgery is usually the first line of treatment for patients with CRC but many tumors with similar histopathological features show significantly different clinical outcomes. The discovery of robust prognostic biomarkers in patients with CRC is imperative to achieve more effective treatment strategies and improve patient's care. Recent progress in next generation sequencing methods and transcriptome analysis has revealed that a much larger part of the genome is transcribed into RNA than previously assumed. Collectively referred to as non-coding RNAs (ncRNAs), some of these RNA molecules such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) have been shown to be altered and to play critical roles in tumor biology. This discovery leads to exciting possibilities for personalized cancer diagnosis, and therapy. Many lncRNAs are tissue and cancer-type specific and have already revealed to be useful as prognostic markers. In this review, we focus on recent findings concerning aberrant expression of lncRNAs in CRC tumors and emphasize their prognostic potential in CRC. Further studies focused on the mechanisms of action of lncRNAs will contribute to the development of novel biomarkers for diagnosis and disease progression.

The long non-coding RNA TUG1 indicates a poor prognosis for colorectal cancer and promotes metastasis by affecting epithelial-mesenchymal transition

BACKGROUND

Long intergenic non-coding RNAs (lncRNAs) are a class of non-coding RNAs that are involved in gene expression regulation. Taurine up-regulated gene 1 (TUG1) is a cancer progression related lncRNA in some tumor oncogenesis; however, its role in colorectal cancer (CRC) remains unclear. In this study, we determined the expression patterns of TUG1 in CRC patients and explored its effect on CRC cell metastasis using cultured representative CRC cell lines.

METHODS

The expression levels of TUG1 in 120 CRC patients and CRC cells were determined using quantitative real-time PCR. HDACs and epithelial-mesenchymal transition (EMT)-related gene expression were determined using western blot. CRC cell metastasis was assessed by colony formation, migration assay and invasion assay.

RESULTS

Our data showed that the levels of TUG1 were upregulated in both CRC cell lines and primary CRC clinical samples. TUG1 upregulation was closely correlated with the survival time of CRC patients. Overexpression of TUG1 in CRC cells increased their colony formation, migration, and invasion in vitro and promoted their metastatic potential in vivo, whereas knockdown of TUG1 inhibited the colony formation, migration, and invasion of CRC cells in vitro. It is also worth pointing out that TUG1 activated EMT-related gene expression.

CONCLUSION

Our data suggest that tumor expression of lncRNA TUG1 plays a critical role in CRC metastasis. TUG1 may have potential roles as a biomarker and/or a therapeutic target in colorectal cancer.

LncRNAs: key players and novel insights into cervical cancer

Cervical cancer contributed the second highest number of deaths in female cancers, exceeded only by breast cancer, carrying high risks of morbidity and mortality. There was a great need and urgency in searching novel treatment targets and prognosis biomarkers to improve the survival rate of cervical cancer patients. Many long non-coding RNAs (lncRNAs) were emerging as pivotal regulators in various biological processes and took vitally an effect on the oncogenesis and progression of cervical cancer. In this review, we summarized the origin and overview function of lncRNAs; highlighted the roles of lncRNAs in cervical cancer in terms of prognosis and tumor progression, invasion and metastasis, apoptosis, and radio-resistance; and outlined the molecular mechanisms of lncRNAs in cervical cancer from the aspects of the interaction of lncRNAs with proteins/mRNAs (especially in HPV protein) and miRNAs, as well as RNA N-methyladenosine (m6A) methylation of lncRNAs. Meanwhile, the application of lncRNAs as biomarkers in cervical cancer prognosis and predictors for metastasis was also discussed. An overview of these researches will be valuable for broadening horizons into mechanisms, selection of meritorious biomarkers for diagnosis as well as prognosis, and future targeted therapy of cervical cancer.