Noncoding RNA and colorectal cancer: its epigenetic role

A Review on Emerging Techniques for Diagnosis of Colorectal Cancer

Common detection methods in practice for diagnosing colorectal cancer (CRC) are painful and invasive leading to less participation of individuals for CRC diagnosis. Whereas, improved or enhanced imaging systems and other minimally invasive techniques with shorter detection times deliver greater detail and less discomfort in individuals. Thus, this review is a summary of the diagnostic tests, ranging from the simple potential use in developing a flexible CRC treatment to the patient's potential benefits in receiving less invasive procedures and the advanced treatments that might provide a better assessment for the diagnosis of CRC and reduce the mortality related to CRC.

Insights into the regulatory role of RNA methylation modifications in glioma

Epitranscriptomic abnormalities, which are highly prevalent in primary central nervous system malignancies, have been identified as crucial contributors to the development and progression of gliomas. RNA epitranscriptomic modifications, particularly the reversible modification methylation, have been observed throughout the RNA cycle. Epitranscriptomic modifications, which regulate RNA transcription and translation, have profound biological implications. These modifications are associated with the development of several cancer types. Notably, three main protein types-writers, erasers, and readers, in conjunction with other related proteins, mediate these epitranscriptomic changes. This review primarily focuses on the role of recently identified RNA methylation modifications in gliomas, such as N6-methyladenosine (m6A), 5-methylcytosine (m5C), N7-methylguanosine (m7G), and N1-methyladenosine (m1A). We delved into their corresponding writers, erasers, readers, and related binding proteins to propose new approaches and prognostic indicators for patients with glioma.

Long noncoding RNA Meg3 sponges miR-708 to inhibit intestinal tumorigenesis via SOCS3-repressed cancer stem cells growth

BACKGROUND

Colorectal cancer (CRC) remains the most common gastrointestinal cancer and a leading cause of cancer deaths worldwide, with most showing pathologies indicating the malignant transformation of early stage intestinal stem cells. The long non-coding RNA Meg3, which functions as a tumor suppressor, has been reported to be abnormal in multiple tumorigenesis events; however, the underlying mechanism by which Meg3 contributes to the malignant proliferation of colonic stem cells remains unclear.

METHODS

We analyzed the expression levels of Meg3, miR-708, and SOCS3 in samples from Apc loss-of-function (Apc^min) mice and patients with CRC, particularly in colonic crypt cells. Apc^min mice and AMO/DSS-induced mice model (in vivo) and organoid culture system (in vitro) were used to explore the effect of the Meg3/miR-708/SOCS3 axis on tumorigenesis in the colon. In vitro, we performed RNApull-down, RNA immunoprecipitation, and luciferase reporter assays using DLD1 and RKO cell lines.

FINDINGS

The Meg3/miR-708/SOCS3 signaling axis plays a critical role in the early stage of CRC development. Our data showed Meg3 levels negatively correlate with miR-708 levels both in clinical samples and in the Apc^min mouse model, which indicated that Meg3 acts as a competitive endogenous RNA (ceRNA) of miR-708. Then, miR-708 served as an oncogene, inducing neoplasia in both Apc^min mice and cultured colonic organoids. Put together, miR-708 appears to promote malignant proliferation of colonic stem cells by targeting SOCS3/STAT3 signaling.

INTERPRETATION

These data revealed that Meg3 sponges miR-708 to inhibit CRC development via SOCS3-mediated repression of the malignant proliferation of colonic stem cells. The Meg3/miR-708/SOCS3 signaling axis provides potential targets for the diagnosis and treatment of CRC, particularly early stage CRC.

SH3PXD2A-AS1/miR-330-5p/UBA2 ceRNA network mediates the progression of colorectal cancer through regulating the activity of the Wnt/β-catenin signaling pathway

Long non-coding RNAs have important roles in the occurrence and progression of various cancers. However, the molecular mechanism of lncRNAs in colorectal cancer (CRC) is not well illustrated. Thus, we used bioinformatics methods to find potential lncRNAs associated with CRC progression, and chose SH3PXD2A-AS1 as a candidate for further analysis. The roles of SH3PXD2A-AS1 in CRC cells were determined by CCK-8, transwell invasion, wound healing and flow cytometry assays. Besides, we established the CRC tumor models in nude mice to study the effect of SH3PXD2A-AS1 on the tumor growth. Based on the ceRNA hypothesis, we used miRDB and miRTarBase websites to identify the SH3PXD2A-AS1-related ceRNA regulatory network, and measured the roles of this network in CRC cells. The results revealed that the expression profiles of SH3PXD2A-AS1 from GEO and TCGA databases showed an aberrant high level in CRC tissues compared with colorectal normal tissues. SH3PXD2A-AS1 over-expression was also found in CRC cells. SH3PXD2A-AS1 knockdown inhibited the CRC cellular proliferation, invasion and migration but induced apoptosis. Besides, SH3PXD2A-AS1 knockdown also suppressed the growth of CRC tumors. Furthermore, SH3PXD2A-AS1 could function as a ceRNA of miR-330-5p. Additionally, UBA2 was proved to be a target gene of miR-330-5p. Moreover, SH3PXD2A-AS1 knockdown downregulated UBA2 expression through sponging miR-330-5p to inactivate the Wnt/β-catenin signaling pathway, thereby inhibiting the cell growth and promoting apoptosis. Therefore, the SH3PXD2A-AS1/miR-330-5p/UBA2 network could regulate the progression of CRC through the Wnt/β-catenin pathway. These findings offer new sights for understanding the pathogenesis of CRC and provide potential biomarkers for CRC treatment.

SNHG9 promotes Hepatoblastoma Tumorigenesis via miR-23a-5p/Wnt3a Axis

Background: Hepatoblastoma is a common hepatic tumor occurring in children between 0-5 years. Accumulating studies have shown lncRNA's potential role in distinct cancer progression and development, including hepatoblastoma. SnoRNA host gene 9 (SNHG9) is associated with the progression of distinct human cancers, but, its specific molecular mechanisms in hepatoblastoma is not unknown.

Methods: In this study, we estimated SNHG9 expression in hepatoblastoma tissue and cell lines by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). Next, we downregulated and upregulated SNHG9 expression in hepatoblastoma cell lines and then determined cell proliferation (CCK-8), colony formation, and cellular apoptosis activity. The dual luciferase reporter activity, RNA immunoprecipitation (RIP), biotin RNA pull down and Spemann's Pearson correlation coefficient assay were performed to establish the interaction between SNHG9, WNt3a and miR- 23a-5p. A xenograft in-vivo tumorgenicity test was performed to elucidate the role of SNHG9 hepatoblastoma in tumorigenesis. SNHG9 role in Cisplatin drug resistance in hepatoblastoma was also determined.

Results: SNHG9 was significantly upregulated in hepatoblastoma tissue and cell lines. SNHG9 overexpression on HUH6 & HepG2 resulted in a significant increase in cell proliferation and clonogenic activity while SNHG9 knock down resulted in a sustained inhibition of cell proliferation and clonogenic activity. Dual luciferase activity, RNA immunoprecipitation and biotin pull down confirmed the direct interaction of miR-23a-5p with SNHG9. The xenograft tumorgenicity test showed SNHG9 downregulation significantly inhibited the tumor growth in BALB/c mice. ROC and Kaplan-Meier analysis showed potential prognostic and diagnostic importance of SNHG9 in hepatoblastoma.

Conclusion: We concluded that SNHG9/miR-23a-5p/Wnt3a axis promotes the progression hepatoblastoma tumor.

Accurate Prediction of Prognosis by Integrating Clinical and Molecular Characteristics in Colon Cancer

Various factors affect the prognosis of patients with colon cancer. Complicated factors are found to be conducive to accurate assessment of prognosis. In this study, we developed a series of prognostic prediction models for survival time of colon cancer patients after surgery. Analysis of nine clinical characteristics showed that the most important factor was the positive lymph node ratio (LNR). High LNR was the most important clinical factor affecting 1- and 3-year survival; M0&age < 70 was the most important feature for 5 years. The performance of the model was improved through the integration of clinical characteristics and four types of molecule features (mRNA, lncRNA, miRNA, DNA methylation). The model provides guidance for clinical practice. According to the high-risk molecular features combined with age ≥ 70&T3, poorly differentiated or undifferentiated, M0&well differentiated, M0&T2, LNR high, T4&poorly differentiated, or undifferentiated, the survival time may be less than 1 year; for patients with high risk of molecular features combined with M0&T2, M0&T4, LNR 0& M0, LNR median &T3, and LNR high, the survival is predicted less than 3 years; and the survival of patients with M1&T3, M0 and high risk molecular features is less than 5 years. Using multidimensional and complex patient information, this study establishes potential criteria for clinicians to evaluate the survival of patients for colon cancer.

The Role of non-coding RNAs in colorectal cancer, with a focus on its autophagy

Colorectal cancer (CRC) is one of malignant afflictions burdening people worldwide, mainly caused by shortages of effective medical intervention and poorly mechanistic understanding of the pathogenesis of CRC. Non-coding RNAs (ncRNAs) are a type of heterogeneous transcripts without the capability of coding protein, but have the potency of regulating protein-coding gene expression. Autophagy is an evolutionarily conserved catabolic process in which cytoplasmic contents are delivered to cellular lysosomes for degradation, resulting in the turnover of cellular components and producing energy for cell functions. A growing body of evidence reveals that ncRNAs, autophagy, and the crosstalks of ncRNAs and autophagy play intricate roles in the initiation, progression, metastasis, recurrence and therapeutic resistance of CRC, which confer ncRNAs and autophagy to serve as clinical biomarkers and therapeutic targets for CRC. In this review, we sought to delineate the complicated roles of ncRNAs, mainly including miRNAs, lncRNAs and circRNAs, in the pathogenesis of CRC, particularly focus on the regulatory role of ncRNAs in CRC-related autophagy, attempting to shed light on the complex pathological mechanisms, involving ncRNAs and autophagy, responsible for CRC tumorigenesis and development, so as to underpin the ncRNAs- and autophagy-based therapeutic strategies for CRC in clinical setting.

miR‑18a‑5p promotes melanoma cell proliferation and inhibits apoptosis and autophagy by targeting EPHA7 signaling

Micro (mi)RNAs serve crucial roles in cancer development although little is known about their cellular mechanisms in the pathogenesis of melanoma. The present study explored the regulatory roles of miR-18a-5p in melanoma cell proliferation, apoptosis and autophagy, in addition to its target gene in melanoma cells. miRNA and ephrin receptor A7 (EPHA7) mRNA were analyzed by reverse transcription-quantitative PCR. Cell Counting Kit-8 and colony formation assays were performed to examine the cell proliferation rate. Hoechst staining and flow cytometry were performed to investigate cell apoptosis. Western blotting was used to estimate the abundance of proteins. Dual-Luciferase reporter assay verified the binding of miRNA with target gene sequences. Melanoma tissues and cell lines exhibited markedly elevated miR-18a-5p expression. miR-18a-5p inhibitor inhibited proliferation rates, and triggered apoptosis and autophagy marker protein expression in WM266-4 and A375 cells. It also negatively regulated EPHA7 expression in WM266-4 and A375 cells by directly binding at the 3′-untranslated region of EPHA7. miR-18a-5p mimics reversed the EPHA7 overexpression-induced suppression of proliferation, and the EPHA7 overexpression-induced promotion of apoptosis and autophagy. miR-18a-5p triggered proliferation of melanoma cells and inhibited apoptosis and autophagy by directly targeting and inhibiting EPHA7 expression. Thus, the present study aided our understanding of miRNA-mediated melanoma pathogenesis.

CircTP53 promotes colorectal cancer by acting as a miR-876-3p sponge to increase cyclin-dependent kinase-like 3 expression

According to ceRNA theory, circular RNAs could regulate certain protein expression through targeting corresponding microRNAs to affect the progression of multiple diseases, including colorectal cancer. CircTP53 (hsa_circ_0107702), highly expressed in thyroid cancer tissues, could promote the proliferation of thyroid cancer. However, the function of circTP53 in colorectal cancer is still unclear. In our study, we found circTP53 was significantly up-regulated in colorectal cancer tissues from patients and in colorectal cell lines. Next, using colorectal cell lines, we confirmed that circTP53 promoted the proliferation, migration and invasion, and reduced the apoptotic rate. Furthermore, through bioinformatics analysis and experimental confirmation, we found circTP53 functioned as the sponge of miR-876-3p, and miR-876-3p reversed the phenotype of circTP53 on the facilitation of colorectal cancer. Additionally, we found circTP53 promoted the progression of colorectal cancer by elevating the expression of CDKL3. At last, we suggested that circTP53 knockdown could inhibit colorectal cancer progression in vivo. In conclusion, circTP53 was highly expressed in colorectal cancer tissues, and promoted colorectal cancer progression via modulating miR-876-3p/CDKL3 axis.

Serrated lesions of the colon and rectum: Emergent epidemiological data and molecular pathways

In 2010, serrated polyps (SP) of the colon have been included in the WHO classification of digestive tumors. Since then a large corpus of evidence focusing on these lesions are available in the literature. This review aims to analyze the present data on the epidemiological and molecular aspects of SP. Hyperplastic polyps (HPs) are the most common subtype of SP (70–90%), with a minimal or null risk of malignant transformation, contrarily to sessile serrated lesions (SSLs) and traditional serrated adenomas (TSAs), which represent 10–20% and 1% of adenomas, respectively. The malignant transformation, when occurs, is supported by a specific genetic pathway, known as the serrated-neoplasia pathway. The time needed for malignant transformation is not known, but it may occur rapidly in some lesions. Current evidence suggests that a detection rate of SP ≥15% should be expected in a population undergoing screening colonoscopy. There are no differences between primary colonoscopies and those carried out after positive occult fecal blood tests, as this screening test fails to identify SP, which rarely bleed. Genetic similarities between SP and interval cancers suggest that these cancers could arise from missed SP. Hence, the detection rate of serrated-lesions should be evaluated as a quality indicator of colonoscopy. There is a lack of high-quality longitudinal studies analyzing the long-term risk of developing colorectal cancer (CRC), as well as the cancer risk factors and molecular tissue biomarkers. Further studies are needed to define an evidence-based surveillance program after the removal of SP, which is currently suggested based on experts’ opinions.

Epigenetic Mechanisms of LncRNAs Binding to Protein in Carcinogenesis

Epigenetic dysregulation is an important feature for cancer initiation and progression. Long non-coding RNAs (lncRNAs) are transcripts that stably present as RNA forms with no translated protein and have lengths larger than 200 nucleotides. LncRNA can epigenetically regulate either oncogenes or tumor suppressor genes. Nowadays, the combined research of lncRNA plus protein analysis is gaining more attention. LncRNA controls gene expression directly by binding to transcription factors of target genes and indirectly by complexing with other proteins to bind to target proteins and cause protein degradation, reduced protein stability, or interference with the binding of other proteins. Various studies have indicated that lncRNA contributes to cancer development by modulating genes epigenetically and studies have been done to determine which proteins are combined with lncRNA and contribute to cancer development. In this review, we look in depth at the epigenetic regulatory function of lncRNAs that are capable of complexing with other proteins in cancer development.

Long non-coding RNA HOTAIR as a competitive endogenous RNA to sponge miR-206 to promote colorectal cancer progression by activating CCL2

Colorectal cancer (CRC) is one of the common malignant tumors, the incidence of which is on rise. LncHOTAIR, considered as an oncogene, contributed to the progression of a lot of cancers. However, the molecular mechanism and biological functions of the HOTAIR/miR-206/CCL2 axis have not been reported before. Here, our research aimed to explore HOTAIR/miR-206/CCL2 axis in CRC to demonstrate its role in predicting the poor prognosis of CRC. LncHOTAIR, miR-206 and CCL2 mRNA were detected in CRC tissues and cells by RT-PCR. The interactions among LncHOTAIR, miR-206 and CCL2 were explored by luciferase reporter assay, qRT-PCR, western blot and RNA interfere. Flow Cytometry Cell Analysis was performed to detect cell cycle and apoptosis as well as colony assay was prepared to test the cell proliferation. Immunohistochemical analysis was used to detect the CCL2 protein in CRC tissues. In our study, silence of LncHOTAIR by RNA interference could suppress the proliferation, migration and invasion of CRC cells. Mechanistically, LncHOTAIR downregulated miR-206 abundance which indicated that LncHOTAIR was considered as a competing endogenous RNA (ceRNA) by directly sponging miR-206 in CRC cells. In addition, further exploration suggested that miR-206 could inhibit the function of the downstream CCL2, the expression of which was repressed by LncHOTAIR/miR-206 signaling. Furthermore, we verified that the overexpression of CCL2 attenuated CRC cell proliferation, migration, invasion. Overall, this study firstly elucidated that LncHOTAIR played as oncogene in CRC via directly sponging miR-206 to activate the downstream CCL2, which would be considered as the novel therapeutic target in CRC.

Epigenetics of colorectal cancer: biomarker and therapeutic potential

Colorectal cancer (CRC), a leading cause of cancer-related death worldwide, evolves as a result of the stepwise accumulation of a series of genetic and epigenetic alterations in the normal colonic epithelium, leading to the development of colorectal adenomas and invasive adenocarcinomas. Although genetic alterations have a major role in a subset of CRCs, the pathophysiological contribution of epigenetic aberrations in this malignancy has attracted considerable attention. Data from the past couple of decades has unequivocally illustrated that epigenetic marks are important molecular hallmarks of cancer, as they occur very early in disease pathogenesis, involve virtually all key cancer-associated pathways and, most importantly, can be exploited as clinically relevant disease biomarkers for diagnosis, prognostication and prediction of treatment response. In this Review, we summarize the current knowledge on the best-studied epigenetic modifications in CRC, including DNA methylation and histone modifications, as well as the role of non-coding RNAs as epigenetic regulators. We focus on the emerging potential for the bench-to-bedside translation of some of these epigenetic alterations into clinical practice and discuss the burgeoning evidence supporting the potential of emerging epigenetic therapies in CRC as we usher in the era of precision medicine.

Directional association test reveals high-quality putative cancer driver biomarkers including noncoding RNAs

Background

Most statistical methods used to identify cancer driver genes are either biased due to choice of assumed parametric models or insensitive to directional relationships important for causal inference. To overcome modeling biases and directional insensitivity, a recent statistical functional chi-squared test (FunChisq) detects directional association via model-free functional dependency. FunChisq examines patterns pointing from independent to dependent variables arising from linear, non-linear, or many-to-one functional relationships. Meanwhile, the Functional Annotation of Mammalian Genome 5 (FANTOM5) project surveyed gene expression at over 200,000 transcription start sites (TSSs) in nearly all human tissue types, primary cell types, and cancer cell lines. The data cover TSSs originated from both coding and noncoding genes. For the vast uncharacterized human TSSs that may exhibit complex patterns in cancer versus normal tissues, the model-free property of FunChisq provides us an unprecedented opportunity to assess the evidence for a gene’s directional effect on human cancer.

Results

We first evaluated FunChisq and six other methods using 719 curated cancer genes on the FANTOM5 data. FunChisq performed best in detecting known cancer driver genes from non-cancer genes. We also show the capacity of FunChisq to reveal non-monotonic patterns of functional association, to which typical differential analysis methods such as t-test are insensitive. Further applying FunChisq to screen unannotated TSSs in FANTOM5, we predicted 1108 putative cancer driver noncoding RNAs, stronger than 90% of curated cancer driver genes. Next, we compared leukemia samples against other samples in FANTOM5 and FunChisq predicted 332/79 potential biomarkers for lymphoid/myeloid leukemia, stronger than the TSSs of all 87/100 known driver genes in lymphoid/myeloid leukemia.

Conclusions

This study demonstrated the advantage of FunChisq in revealing directional association, especially in detecting non-monotonic patterns. Here, we also provide the most comprehensive catalog of high-quality biomarkers that may play a causative role in human cancers, including putative cancer driver noncoding RNAs and lymphoid/myeloid leukemia specific biomarkers.

Electronic supplementary material

The online version of this article (10.1186/s12920-019-0565-9) contains supplementary material, which is available to authorized users.

Long Non-Coding RNA STARD13-AS Suppresses Cell Proliferation And Metastasis In Colorectal Cancer

Background

Dysregulation of long non-coding RNAs (lncRNAs) is closely related with the progression of cancer in humans. The functional and regulatory roles of lncRNAs in colorectal cancer (CRC) are still largely unclear. The purpose of this study is to explore the function of lncRNA STARD13-AS in CRC.

Methods

The bioinformatics tool “GEPIA” was used to predict the potential expression of STARD13-AS in CRC. qRT-PCR was used to evaluate the relative expression level of STARD13-AS in CRC cells lines and tissues samples. The functional involvement of STARD13-AS in the CRC cells was assessed using MTT assay, flow cytometry, and Transwell assay. The expression levels of cyclin D, cyclin E, E-cadherin, N-cadherin, and vimentin were assessed using Western blot.

Results

Bioinformatics prediction and qRT-PCR results showed that STARD13-AS expression was decreased in CRC tissues. Patients with low STARD13-AS expression exhibited distant and lymphatic metastasis as well as enhancement in tumor size. STARD13-AS expression was downregulated in CRC cell lines compared to normal human colon mucosal epithelial cell line NCM460 and STARD13-AS expression in SW620 and LoVo cell lines was lowest. Moreover, we observed that while STARD13-AS overexpression suppressed the cell cycle, proliferation, migration, and invasion, while promoted apoptosis both in LoVo and SW620 cells. In addition, STARD13-AS overexpression inhibited Cyclin E, Cyclin D, N-cadherin and vimentin expression, and promoted E-cadherin expression both in LoVo and SW620 cells.

Conclusion

Expression of STARD13-AS suppresses cell proliferation and metastasis in CRC, suggesting that STARD13-AS might act as a potential target for CRC treatment.

Long noncoding RNA MIR31HG abrogates the availability of tumor suppressor microRNA-361 for the growth of osteosarcoma

Purpose

Long noncoding RNA (LncRNA) containing microRNA host gene is an interesting type of LncRNA. MicroRNA-31 (miR-31)-host gene LncRNA (MIR31HG) have been recognized as an oncogene in many cancers, but not in osteosarcoma (OS). Interestingly, MIR31HG/miR-31 could not regulate each other’s expression in certain cancer, suggesting that the role of MIR31HG in cancer is independent of miR-31. We here investigated the function and potential mechanism of MIR31HG in OS.

Methods

OS tissues and adjacent non-tumor tissues (n=40) were collected to determine the expressions of MIR31HG by paired t-test. We here identified the miRNAs predicted to be bound to MIR31HG and investigated the impacts of MIR31HG on cell growth and metastasis of OS cells by CCK-8, flow cytometry, Transwell assay, Western blot, etc. in vitro and in vivo.

Results

MIR31HG was upregulated in OS tissues and OS cell lines. The patients with high expression of MIR31HG have high tumor stages and distant metastasis. Tumor suppressor miR-361, but not miR-31, was confirmed to be sponged directly by MIR31HG in OS cells and was down-regulated in OS cell lines. Knockdown of MIR31HG restored the expression of miR-361. Restoration of miR-361 level in Saos-2 and U2OS cells induced cell apoptosis and G1/S arrest, inhibited proliferation and migration, which was, however, abrogated by MIR31HG. Mechanistically, cell growth and metastasis-related target genes of MIR-361 including VEGF, FOXM1 and Twist were de-repressed in OS cells by MIR31HG overexpression, leading to upregulated BCL2, CCND1 and epithelial–mesenchymal transition (EMT) phenotype. Patients with high expression of MIR31HG also showed more VEGF, FOXM1 and Twist levels. Overexpression of MIR31HG in vivo also promoted tumor growth via inhibition of miR-361 signals and elevated the expression of VEGF, FOXM1 and Twist for tumor growth.

Conclusion

MIR31HG acts as an oncogene in OS for tumor progression via regulation of tumor suppressor miR-361 and its target genes.

Impact of the gut microbiome on the genome and epigenome of colon epithelial cells: contributions to colorectal cancer development

In recent years, the number of studies investigating the impact of the gut microbiome in colorectal cancer (CRC) has risen sharply. As a result, we now know that various microbes (and microbial communities) are found more frequently in the stool and mucosa of individuals with CRC than healthy controls, including in the primary tumors themselves, and even in distant metastases. We also know that these microbes induce tumors in various mouse models, but we know little about how they impact colon epithelial cells (CECs) directly, or about how these interactions might lead to modifications at the genetic and epigenetic levels that trigger and propagate tumor growth. Rates of CRC are increasing in younger individuals, and CRC remains the second most frequent cause of cancer-related deaths globally. Hence, a more in-depth understanding of the role that gut microbes play in CRC is needed. Here, we review recent advances in understanding the impact of gut microbes on the genome and epigenome of CECs, as it relates to CRC. Overall, numerous studies in the past few years have definitively shown that gut microbes exert distinct impacts on DNA damage, DNA methylation, chromatin structure and non-coding RNA expression in CECs. Some of the genes and pathways that are altered by gut microbes relate to CRC development, particularly those involved in cell proliferation and WNT signaling. We need to implement more standardized analysis strategies, collate data from multiple studies, and utilize CRC mouse models to better assess these effects, understand their functional relevance, and leverage this information to improve patient care.

Clinicopathological, genomic and immunological factors in colorectal cancer prognosis

BACKGROUND

Numerous factors affect the prognosis of colorectal cancer (CRC), many of which have long been identified, such as patient demographics and the multidisciplinary team. In more recent years, molecular and immunological biomarkers have been shown to have a significant influence on patient outcomes. Whilst some of these biomarkers still require ongoing validation, if proven to be worthwhile they may change our understanding and future management of CRC. The aim of this review was to identify the key prognosticators of CRC, including new molecular and immunological biomarkers, and outline how these might fit into the whole wider context for patients.

METHODS

Relevant references were identified through keyword searches of PubMed and Embase Ovid SP databases.

RESULTS

In recent years there have been numerous studies outlining molecular markers of prognosis in CRC. In particular, the Immunoscore® has been shown to hold strong prognostic value. Other molecular biomarkers are useful in guiding treatment decisions, such as mutation testing of genes in the epidermal growth factor receptor pathway. However, epidemiological studies continue to show that patient demographics are fundamental in predicting outcomes.

CONCLUSION

Current strategies for managing CRC are strongly dependent on clinicopathological staging, although molecular testing is increasingly being implemented into routine clinical practice. As immunological biomarkers are further validated, their testing may also become routine. To obtain clinically useful information from new biomarkers, it is important to implement them into a model that includes all underlying fundamental factors, as this will enable the best possible outcomes and deliver true precision medicine.

Development and internal validation of a nine-lncRNA prognostic signature for prediction of overall survival in colorectal cancer patients

Background

Colorectal cancer remains a serious public health problem due to the poor prognosis. In the present study, we attempted to develop and validate a prognostic signature to predict the individual mortality risk in colorectal cancer patients.

Materials and Methods

The original study datasets were downloaded from The Cancer Genome Atlas database. The present study finally included 424 colorectal cancer patients with wholly gene expression information and overall survival information.

Results

A nine-lncRNA prognostic signature was built through univariate and multivariate Cox proportional regression model. Time-dependent receiver operating characteristic curves in model cohort demonstrated that the Harrell's concordance indexes of nine-lncRNA prognostic signature were 0.768 (95% CI [0.717-0.819]), 0.778 (95% CI [0.727-0.829]) and 0.870 (95% CI [0.819-0.921]) for 1-year, 3-year and 5-year overall survival respectively. In validation cohort, the Harrell's concordance indexes of nine-lncRNA prognostic signature were 0.761 (95% CI [0.710-0.812]), 0.801 (95% CI [0.750-0.852]) and 0.883 (95% CI [0.832-0.934]) for 1-year, 3-year and 5-year overall survival respectively. According to the median of nine-lncRNA prognostic signature score in model cohort, 424 CRC patients could be stratified into high risk group (n = 212) and low risk group (n = 212). Kaplan-Meier survival curves showed that the overall survival rate of high risk group was significantly lower than that of low risk group (P < 0.001).

Discussion

The present study developed and validated a nine-lncRNA prognostic signature for individual mortality risk assessment in colorectal cancer patients. This nine-lncRNA prognostic signature is helpful to evaluate the individual mortality risk and to improve the decision making of individualized treatments in colorectal cancer patients.

Polymorphisms in non-coding RNAs and risk of colorectal cancer: A systematic review and meta-analysis

Colorectal cancer (CRC) has been regarded as a common cancer due to its prevailing incidence in both males and females. Recently, non-coding RNAs used as biomarkers for screening, diagnosis and prognosis of different cancers have been under the focus of attention. As a result of this, the aim of this study was to systematically review articles that investigated the SNPs in genes related to microRNAs and long non-coding RNAs to assess the genetic susceptibility of colorectal cancer risk. The outcome is presented as the results of a meta-analysis. We systematically searched PubMed, Web of Science, and Scopus to identify relevant studies published up to 20/5/2017. These included eligible studies consisting of 23,581 patients and 22,697 controls. The conferred risk was estimated and presented using odds ratios (ORs) and 95% confidence intervals (CI). The Hardy-Weinberg equilibrium (HWE) was assessed by the goodness-of-fit chi-square test in all studies. The power of each study was also calculated based on the available results. Out of 27 different microRNAs which had published results, although most of the studies were under powered, miR-146a and miR-196a were amongst the most studied microRNAs. For five miRNAs (miR-196a, miR-146a, miR-27a, miR-499 and miR-149) which we performed a meta-analysis, miR-27a and miR-149 gene polymorphisms were associated with susceptibility to CRC. Other miRNAs did not show any effect on the CRC risk. Overall, significant association between miR-149 rs2292832 and susceptibility to cancer was identified in a recessive genetic model, TT/ (TC + CC) (OR = 1.19, 95% CI = 1.02-1.39, P = 0.02). On the other hand, rs895819 (miR-27a) GG carriers were more susceptible to CRC (OR = 1.47, 95% CI = 1.21-1.78, P = <0.05) in a recessive genetic model. Analysis of the data based on race revealed that rs2910164 (miR-146a) polymorphism may decrease the risk of CRC among Europeans, in a co dominant model [OR = 0.81, 95% CI 0.66-0.99, p = 0.04], but not among Asians. In conclusion, certain miRNAs (miR-27a and miR-149) may affect the CRC risk and can be regarded as genetic markers amongst different populations. LncRNAs still have to be studied more to reach a conclusion for their association with CRC risk.

Differentially expressed lncRNAs and mRNAs identified by NGS analysis in colorectal cancer patients

Long noncoding RNAs (lncRNAs) play an important role in gene regulation, but their impact on the pathogenesis of colorectal cancer and the biological function of cancer cells is unclear. In this study, we used next‐generation sequencing to study the differences in the expression profiles of lncRNAs and mRNAs in colorectal cancer tissues. We analyzed the differentially expressed genes by Gene Ontology/Kyoto Encyclopedia of Genes and Genomes (GO/KEGG) enrichment and predicted new lncRNA functions. Our results revealed that compared with lncRNAs and mRNAs in nontumor colorectal tissues, 1019 lncRNAs (512 upregulated, 507 downregulated) and 3221 mRNAs (1606 upregulated, 1615 downregulated) were differentially expressed in tumor colorectal tissues (fold change >2 and P < 0.05). We validated some of these genes by qPCR. Furthermore, we identified some new lncRNAs differently expressed in colorectal cancer samples from patients in northern China. We confirmed the function of lncRNA‐FIRRE‐201 and SLCO4A1‐AS1‐202 in colorectal cancer cells to provide an experimental basis for studies on their roles in the occurrence and development of colorectal cancer and in the regulation of networks.

Circulating PIWI-Interacting RNAs piR-5937 and piR-28876 Are Promising Diagnostic Biomarkers of Colon Cancer

Background: The early detection of colon cancer is one of the main prerequisites for successful treatment and mortality reduction. Circulating PIWI-interacting RNAs (piRNA) were recently identified as novel promising biomarkers. The purpose of the study was to assess the profiles of piRNAs in blood serum of colon cancer patients with the aim to identify those with high diagnostic potential.Methods: Blood serum samples from 403 colon cancer patients and 276 healthy donors were included in this 3-phase biomarker study. Large-scale piRNA expression profiling was performed using Illumina small RNA sequencing. The diagnostic potential of selected piRNAs was further validated on independent training and validation sets of samples using RT-qPCR.Results: In total, 31 piRNAs were found to be significantly deregulated in serum of cancer patients compared with healthy donors. Based on the levels of piR-5937 and piR-28876, it was possible to differentiate between cancer patients and healthy donors with high sensitivity and specificity. Moreover, both piRNAs exhibited satisfactory diagnostic performance also in patients with stage I disease and enabled detection of colon cancer with higher sensitivity than currently used biomarkers CEA and CA19-9. Finally, the expression of analyzed piRNAs in blood restored significantly 1 month after the surgical resection.Conclusions: Based on our findings, piRNAs are abundant in human blood serum. Furthermore, their levels in colon cancer have been observed to be significantly deregulated. However, their involvement in carcinogenesis must be further established.Impact: piRNAs could serve as promising noninvasive biomarkers for early detection of colon cancer. Cancer Epidemiol Biomarkers Prev; 27(9); 1019-28. ©2018 AACR.

Long non-coding RNA MIAT promotes growth and metastasis of colorectal cancer cells through regulation of miR-132/Derlin-1 pathway

Objective

Recently, long non-coding RNA (lncRNA) MIAT has been demonstrated as an oncogenic gene in several types of cancer. However, the role and mechanism of MIAT in colorectal cancer (CRC) have not been investigated.

Methods

Real-time PCR was used to measure MIAT expression in CRC tissues and cells. Small interfering RNA specific for MIAT (si-MIAT) was used to down-regulate MIAT expression in CRC cells. The interaction of MIAT and miR-132 was measured by RNA pull-down assay. The effect of si-MIAT on CRC cells apoptosis and metastasis were measured by flow cytometry assay, invasion and migration assay, respectively.

Results

In present study, we found that MIAT was highly expressed in CRC tissues and cells. MIAT knockdown inhibited proliferation, migration and invasion and enhanced apoptosis of CRC cells. Further, we demonstrated that MIAT acted as a competing endogenous RNA for miR-132, antagonized its functions, and resulted in the de-repression of its target gene Derlin-1, which acted as an oncogene in promoting growth and metastasis of CRC cells. In LOVO and SW480 cells with si-MIAT, miR-132 inhibitor resulted in an increase of cell proliferation, migration and invasion and a decrease of cell apoptosis, which was partially abolished by transfection of Derlin-1 shRNA.

Conclusions

Our data indicated that highly expressed MIAT was an oncogenic lncRNA that promoted the growth and metastasis of CRC through miR-132/Derlin-1 axis.

Dual strands of the miR-223 duplex (miR-223-5p and miR-223-3p) inhibit cancer cell aggressiveness: targeted genes are involved in bladder cancer pathogenesis

Analyses of microRNA (miRNA) expression signatures obtained by RNA sequencing revealed that some passenger miRNAs (miR-144-5p, miR-145-3p, miR-149-3p, miR-150-3p, and miR-199a-3p) acted as anti-tumor miRNAs in several types of cancer cells. The involvement of passenger strands in the pathogenesis of human cancer is a novel concept. Based on the miRNA signature of bladder cancer (BC) obtained by RNA sequencing, we focused on both strands of the miR-223-duplex (miR-223-5p and miR-223-3p) and investigated their functional significance in BC cells. Ectopic expression of these miRNAs showed that both miR-223-3p (the guide strand) and miR-223-5p (the passenger strand) inhibited cancer cell migration and invasion of BC cells. The role of miR-223-5p (the passenger strand) has not been well studied. Combining gene expression studies and in silico database analyses, we demonstrated the presence of 20 putative target genes that could be regulated by miR-223-5p in BC cells. Among these targets, high expression of five genes (ANLN, INHBA, OIP5, CCNB1, and CDCA2) was significantly associated with poor prognosis of BC patients based on The Cancer Genome Atlas (TCGA) database. Moreover, we showed that a gene (ANLN) encoding a multifunctional actin-binding protein was directly regulated by miR-223-5p in BC cells. Overexpression of ANLN was observed in BC clinical specimens and high expression of ANLN was significantly associated with poor prognosis of BC patients. We suggest that studies of regulatory cancer networks, including the passenger strands of miRNAs, may provide new insights into the pathogenic mechanisms of BC.

The hypoxia-responsive long non-coding RNAs may impact on the tumor biology and subsequent management of breast cancer

Long non-coding RNAs (lncRNAs) are DNA transcripts longer than 200 nucleotides without protein-coding potential. As they are key regulators of gene expression at chromatic, transcriptional and posttranscriptional level, they play important role in various biological and pathological processes. Dysregulation of lncRNAs has been observed in several diseases including cancer. Breast cancer is heterogeneous disease with many molecular subtypes specific in different prognosis and treatment responses. Hypoxia, a common micro-environmental feature of rapidly growing tumour is associated with metastases, recurrences and resistance to therapy. Aberrant expression of hypoxia related lncRNAs significantly correlates with poor outcomes in cancer patients, as the lncRNAs play an important regulatory role in the breast cancer-cell survival. Thus, a better understanding of lncRNAs role in the hypoxic conditions of breast cancer is crucial for precise understanding of the tumorigenesis, disease features and poor clinical outcome, especially in highly aggressive breast cancer subtypes (HER2-positive and triple-negative types). Moreover, lncRNAs may represent tumour marker predicting prognosis and therapeutic targets improving precise and personalized therapy for better patient´s survival. In this review, we summarize the recent information on lncRNAs in breast cancer with special focus on the hypoxia-responsive lncRNAs and their potential impact on the prognosis, therapy algorithms and individual outcomes. Presented data helps in better understanding of the specific mechanisms predicting new therapeutic agents and strategies for the pharmacological intervention.

Up-regulation of lncRNA SNHG1 indicates poor prognosis and promotes cell proliferation and metastasis of colorectal cancer by activation of the Wnt/β-catenin signaling pathway

Recently, the lncRNA small nucleolar RNA host gene (SNHG1) has been exhibited to be upregulated, which plays a crucial role in the development and prognosis of several cancers. However, the role of the biology and clinical significance of SNHG1 in the tumorigenesis of colorectal cancer (CRC) has rarely been reported. In this work, we firstly found that SNHG1 expression levels were upregulated aberrantly in colorectal cancer tissues and colorectal cancer cell lines. By Kaplan-Meier survival analysis, patients with high SNHG1 expression level had poorer overall survival (OS) and progression-free survival (PFS) than those with low SNHG1 expression. In multivariate analysis, increased SNHG1 expression was proved to be an independent unfavorable prognostic indicator for CRC. In vitro experiments revealed that SNHG1 silencing inhibited the growth and metastasis and induced apoptosis of CRC cell lines. Finally, we found that SNHG1 may induce the activation of the WNT/β-catenin pathway through regulating β-catenin expression and transcription factor-4 (TCF-4), cyclin D1 and MMP-9. Altogether, our findings demonstrated that lncRNA SNHG1, was high expressed in colorectal cancer tissues and may serve as a tumor oncogene through regulating WNT/β-catenin signal pathway, which provided a candidate diagnostic biomarker and a promising therapeutic target for patients with CRC.

A lncRNA-H19 transcript from secondary hair follicle of Liaoning cashmere goat: Identification, regulatory network and expression regulated potentially by its promoter methylation

The H19 transcript (imprinted maternally expressed transcript) is well-known as long noncoding RNA (lncRNA), and it is thought to be associated with the inductive capacity of dermal papilla cells for hair-follicle reconstruction. In this study, we isolated and characterized a lncRNA-H19 transcript from the secondary hair follicle of Liaoning cashmere goat. Also, we investigated its transcriptional pattern and methylation status of H19 gene in secondary hair follicle of this breed during different stages of hair follicle cycle. Nucleotide composition analysis indicated that guanine (G) and cytosine (C) are the dominant nucleotides in the lncRNA-H19 transcript of Liaoning cashmere goat with the highest frequency distribution (11.25%) of GG nucleotide pair. The regulatory network showed that lncRNA-H19 transcript appears to have remarkably diverse regulatory relationships with its related miRNAs and the potential target genes. In secondary hair follicle, the relative expression of lncRNA-H19 transcript at the anagen phase is significantly higher than that at both telogen and catagen phases suggesting that lncRNA-H19 transcript might play essential roles in the formation and growth of cashmere fiber of goat. Methylation analysis indicated that the methylation of the promoter region of H19 gene most likely participates in its transcriptional suppression in secondary hair follicle of Liaoning cashmere goat.

Identification of metastasis-associated microRNAs in serum from rectal cancer patients

MicroRNAs (miRNAs) are promising prognostic and diagnostic biomarkers due to their high stability in blood. Here we investigate the expression of miRNAs and other noncoding (nc) RNAs in serum of rectal cancer patients. Serum from 96 rectal cancer patients was profiled using small RNA sequencing and expression of small RNAs was correlated with the clinicopathological characteristics of the patients. Multiple classes of RNAs were detected, including miRNAs and fragments of tRNAs, snoRNAs, long ncRNAs, and other classes of RNAs. Several miRNAs, miRNA variants (isomiRs) and other ncRNAs were differentially expressed between Stage IV and Stage I-III rectal cancer patients, including several members of the miR-320 family. Furthermore, we show that high expression of miR-320d as well as one tRNA fragment is associated with poor survival. We also show that several miRNAs and isomiRs are differentially expressed between patients receiving preoperative chemoradiotherapy and patients who did not receive any treatment before serum collection. In summary, our study shows that the expression of miRNAs and other small ncRNAs in serum may be used to predict distant metastasis and survival in rectal cancer.

A novel lncRNA, LL22NC03-N64E9.1, represses KLF2 transcription through binding with EZH2 in colorectal cancer

Long noncoding RNAs (lncRNA) have been implicated in variety human cancer but their mechanisms of function are mainly undocumented. In the present study, we investigated lncRNAs alteration that contributed to colorectal cancer (CRC) by utilizing TCGA RNA sequencing data and other publicly available lncRNAs expression profiling data. Here, We screened out the CRC-associated lncRNA LL22NC03-N64E9.1, a key regulator of CRC development and progression. We also revealed that knockdown of LL22NC03-N64E9.1 inhibited cell proliferation, colony formation, tumorigenicity and apoptosis promotion, both in vitro and in vivo. Mechanistically, LL22NC03-N64E9.1 repressed underlying target gene KLF2 transcription through binding to EZH2. Furthermore, rescue experiments revealed that LL22NC03-N64E9.1 oncogenic function may partially depend on repressing KLF2. Taken together, our results suggested that LL22NC03-N64E9.1 confered an oncogenic function in human CRC and may serve as a candidate prognostic biomarker and target for new therapies in this deadly disease.

Regulation of actin-binding protein ANLN by antitumor miR-217 inhibits cancer cell aggressiveness in pancreatic ductal adenocarcinoma

Analysis of our microRNA (miRNA) expression signature of pancreatic ductal adenocarcinoma (PDAC) revealed that microRNA-217 (miR-217) was significantly reduced in cancer tissues. The aim of this study was to investigate the antitumor roles of miR-217 in PDAC cells and to identify miR-217-mediated molecular pathways involved in PDAC aggressiveness. The expression levels of miR-217 were significantly reduced in PDAC clinical specimens. Ectopic expression of miR-217 significantly suppressed cancer cell migration and invasion. Transcription of actin-binding protein Anillin (coded by ANLN) was detected by our in silico and gene expression analyses. Moreover, luciferase reporter assays showed that ANLN was a direct target of miR-217 in PDAC cells. Overexpression of ANLN was detected in PDAC clinical specimens by real-time PCR methods and immunohistochemistry. Interestingly, Kaplan-Meier survival curves showed that high expression of ANLN predicted shorter survival in patients with PDAC by TCGA database analysis. Silencing ANLN expression markedly inhibited cancer cell migration and invasion capabilities of PDAC cell lines. We further investigated ANLN-mediated downstream pathways in PDAC cells. "Focal adhesion" and "Regulation of actin binding protein" were identified as ANLN-modulated downstream pathways in PDAC cells. Identification of antitumor miR-217/ANLN-mediated PDAC pathways will provide new insights into the potential mechanisms underlying the aggressive course of PDAC.

Long noncoding RNA BLACAT1 indicates a poor prognosis of colorectal cancer and affects cell proliferation by epigenetically silencing of p15

Recently, a novel class of transcripts, long noncoding RNAs (lncRNAs), is being identified at a rapid pace. These RNAs have critical roles in diverse biological processes, including tumorigenesis. One of them, BLACAT1, a cancer-associated long noncoding RNA, exerts regulatory functions in various biological processes in cancer cells, however, the role of BLACAT1 in colon cancer remains unclear. Our experiments showed that increased BLACAT1 was an independent unfavorable prognostic indicator for colorectal cancer, and revealed that BLACAT1 knockdown significantly repressed proliferation, both in vitro and in vivo. Mechanistic investigations demonstrated that BLACAT1 had a key role in G1/G0 arrest, and showed that BLACAT1 can repress p15 expression by binding to EZH2, thus contributing to the regulation of CRC cell cycle and proliferation. Our results suggest that BLACAT1, as a cell cycle regulator, may serve as a potential target for colon cancer prevention and treatment in human CRC.

Long Noncoding RNA MEG3 Suppresses Glioma Cell Proliferation, Migration, and Invasion by Acting as a Competing Endogenous RNA of miR-19a

Glioma, with varying malignancy grades and histological subtypes, is the most common primary brain tumor in adults. Long noncoding RNAs (lncRNAs) are non-protein-coding transcripts and have been proven to play an important role in tumorigenesis. Our study aims to elucidate the combined effect of lncRNA maternally expressed gene 3 (MEG3) and microRNA-19a (miR-19a) in human glioma U87 and U251 cell lines. Real-time PCR revealed that MEG3 was downregulated and miR-19a was upregulated in malignant glioma tissues and cell lines. Bioinformatics analyses (TargetScan, miRanda, and starBase V2.0) showed that phosphatase and tensin homolog (PTEN) is a target of miR-19a with complementary binding sites in the 3'-UTR. As expected, luciferase results verified the putative target site and also revealed the complementary binding between miR-19a and MEG3. miR-19a represses the expression of PTEN and promotes glioma cell proliferation, migration, and invasion. However, MEG3 could directly bind to miR-19a and effectively act as a competing endogenous RNA (ceRNA) for miR-19a to suppress tumorigenesis. Our study is the first to demonstrate that lncRNA MEG3 suppresses glioma cell proliferation, migration, and invasion by acting as a ceRNA of miR-19a, which provides a novel insight about the pathogenesis of glioma.

Comprehensive investigation of a novel differentially expressed lncRNA expression profile signature to assess the survival of patients with colorectal adenocarcinoma

Growing evidence has shown that long non-coding RNAs (lncRNAs) can serve as prospective markers for survival in patients with colorectal adenocarcinoma. However, most studies have explored a limited number of lncRNAs in a small number of cases. The objective of this study is to identify a panel of lncRNA signature that could evaluate the prognosis in colorectal adenocarcinoma based on the data from The Cancer Genome Atlas (TCGA). Altogether, 371 colon adenocarcinoma (COAD) patients with complete clinical data were included in our study as the test cohort. A total of 578 differentially expressed lncRNAs (DELs) were observed, among which 20 lncRNAs closely related to overall survival (OS) in COAD patients were identified using a Cox proportional regression model. A risk score formula was developed to assess the prognostic value of the lncRNA signature in COAD with four lncRNAs (LINC01555, RP11-610P16.1, RP11-108K3.1 and LINC01207), which were identified to possess the most remarkable correlation with OS in COAD patients. COAD patients with a high-risk score had poorer OS than those with a low-risk score. The multivariate Cox regression analyses confirmed that the four-lncRNA signature could function as an independent prognostic indicator for COAD patients, which was largely mirrored in the validating cohort with rectal adenocarcinoma (READ) containing 158 cases. In addition, the correlative genes of LINC01555 and LINC01207 were enriched in the cAMP signaling and mucin type O-Glycan biosynthesis pathways. With further validation in the future, our study indicates that the four-lncRNA signature could serve as an independent biomarker for survival of colorectal adenocarcinoma.

Long non-coding RNA FOXP4-AS1 is an unfavourable prognostic factor and regulates proliferation and apoptosis in colorectal cancer

OBJECTIVES

Despite improvements in diagnosis and treatment, colorectal cancer (CRC) remains the third most common malignancy, and fourth-leading cause of cancer-related death worldwide, and has a particularly high incidence in Western countries. Recent studies have suggested that long non-coding RNAs (lncRNAs) compose a novel class of regulators of cancer biological processes, such as proliferation, apoptosis and metastasis. Here, we report that lncRNA FOXP4-AS1 acts as a functional oncogene in CRC pathogenesis. Moreover, we have attempted to investigate the effects of FOXP4-AS1 on tumour progression, both in vitro and in vivo.

MATERIALS AND METHODS

In this study, bioinformatic analyses and qPCR were performed to investigate FOXP4-AS1 expression in CRC tissue samples and CRC cell lines. We inhibited FOXP4-AS1 expression via FOXP4-AS1-specific siRNA transfection. Cell proliferation was assessed using cell viability and colony formation assays, as well as by flow cytometry and ethynyl deoxyuridine (Edu) analyses. Apoptosis was assessed using flow cytometry. Animal tumour xenografts were generated, and immunohistochemistry (IHC) was performed to evaluate effects of FOXP4-AS1 on CRC tumour growth in vivo.

RESULTS

We found that FOXP4-AS1 was up-regulated in CRC tissues and cell lines and that its overexpression positively correlated with advanced pathological stages and larger tumour size. Additionally, we found that FOXP4-AS1 knockdown inhibited cell proliferation and induced apoptosis. Furthermore, FOXP4-AS1 knockdown induced marked increase in number of cells in G0/G1 phase and reduction in number of cells in S phase, in DLD-1, HT-29 and HCT116 cell lines. Consistent with these findings, FOXP4-AS1 silencing inhibited tumour growth in vivo.

CONCLUSION

These findings suggest that FOXP4-AS1 plays a crucial role in CRC progression and may be a new biomarker in patients with CRC.

Increased long noncoding RNA SNHG20 predicts poor prognosis in colorectal cancer

Background

Long noncoding RNAs (lncRNAs) have been suggested to be involved in the development and progression of malignancies. However, the investigation of small nucleolar RNA host gene 20 (SNHG20) on cancer progression remains unknown. The present study aims to explore the clinical significance of SNHG20 and its potential molecular mechanism in colorectal cancer (CRC).

Methods

Quantitative real-time PCR (qRT-PCR) was used to measure the SNHG20 expression in a total of 107 CRC tissues and CRC cell lines. Loss of function approach was employed to explore the biological roles of SNHG20 in vitro. Its potential molecular mechanism was further verified by western blotting and qRT-PCR.

Results

The results suggested that SNHG20 expression was significantly upregulated in CRC tissues compared to corresponding normal tissues from 107 CRC patients. High expression of SNHG20 was remarkably associated with advanced TNM stage in patients with CRC. Multivariate analyses unraveled that SNHG20 expression was an independent prognostic factor for overall survival in CRC patients. Further functional assays revealed that knockdown of SNHG20 suppressed cell proliferation, invasion and migration, and cell cycle progression in CRC cells. Moreover, SNHG20 regulated cell growth through modulation of a series of cell cycle-associated genes.

Conclusions

Our findings suggest that dysregulation of SNHG20 participates in CRC progression and may serve as a potential therapeutic target in CRC patients.