Altered expression of LINC-ROR in cancer cell lines and tissues

Harnessing the supremacy of MEG3 LncRNA to defeat gastrointestinal malignancies

Evidence suggests that long non-coding RNAs (lncRNAs) play a pivotal role in the carcinogenesis and progression of various human malignancies including gastrointestinal malignancies. This comprehensive review reports the functions and mechanisms of the lncRNA maternally expressed gene 3 (MEG3) involved in gastrointestinal malignancies. It summarizes its roles in mediating the regulation of cellular proliferation, apoptosis, migration, invasiveness, epithelial-to-mesenchymal transition, and drug resistance in several gastrointestinal cancers such as colorectal cancer, gall bladder cancer, pancreatic cancer, gastric cancer, esophageal cancer, cholangiocarcinoma, gastrointestinal stromal tumors and most importantly, hepatocellular carcinoma. In addition, the authors briefly highlight its implicated mechanistic role and interactions with different non-coding RNAs and oncogenic signaling cascades. This review presents the rationale for developing non coding RNA-based anticancer therapy via harnessing the power of MEG3 in gastrointestinal malignancies.

The roles of Linc-ROR in the regulation of cancer stem cells

Cancer stem cells (CSCs) are considered to be a kind of tumor cell population characterized by self-renewal, easy to metastasize and drug resistance, which play an indispensable role in the occurrence, development, metastasis and drug resistance of tumors, and their existence is an important reason for high metastasis and recurrence of tumors. Long non-coding RNAs (LncRNAs), which are more than 200 nucleotides in length, have a close relationship with the malignant progression of cancer.In recent years, abundant studies have reavling that LncRNAs are beneficial to the regulation of various cancer stem cells. Linc-ROR, as a newly discovered intergenic non-protein-coding RNA in recent years, is considered to be a key regulator affecting the development of human tumors. Dysregulation of Linc-ROR is related to stemness phenotype and functional regulation of cancer stem cells. For that, Linc-ROR has the potential to be used as a diagnostic biomarker for cancer patients and can serve as a clinically meaningful potential therapeutic target. In this review, we generalize the existing research results on the important role of Linc-ROR in regulation of CSCs.

Down-regulation of LINC-ROR, HOXA-AS2 and MEG3 in gastric cancer

Long non-coding RNAs (lncRNAs) have been identified as modulators of gastric carcinogenesis. Evaluation of expression amounts of these transcripts is a primary but essential step for recognition of the role of lncRNAs in the carcinogenesis. Therefore, we compared expressions of LINC-ROR, HOXA-AS2, MEG3 and HOTTIP lncRNAs in gastric cancer samples and nearby non-cancerous samples. Expression levels of LINC-ROR, HOXA-AS2 and MEG3 lncRNAs have been lower in gastric cancer samples compared with nearby non-cancerous samples (Expression ratios = 0.26, 0.37 and 0.36; P values = 0.021, 0.015 and 0.032, respectively). However, expression levels of HOTTIP were not significantly different between gastric cancer tissues and nearby tissues (P value = 0.43). HOTTIP expression was associated with tumor size (P value = 0.04). In addition, MEG3 expression was associated with site of primary tumor (P = 0.0003). Expressions of LINC-ROR and HOXA-AS2 were not associated with any clinical or pathological parameter. ROC curve analysis revealed that HOXA-AS2 and LINC-ROR could significantly differentiate between gastric cancer samples and nearby non-cancerous tissues (AUC values = 0.68 and 0.64; P values = 0.01 and 0.04, respectively). Taken together, the current investigation provides clues for contribution of LINC-ROR, HOXA-AS2 and MEG3 lncRNAs in gastric carcinogenesis and warrants further mechanistical assays.

Clinicopathological and prognostic significance of long non-coding RNA-ROR in cancer patients: A systematic review and meta-analysis

BACKGROUND

Accumulating studies have focused on the clinicopathological and prognostic roles of large intergenic noncoding RNA regulator of reprogramming (lincRNA-ROR) in cancer patients. However, the results were controversial and unconvincing. Thus, we performed a meta-analysis to assess the associations between lincRNA-ROR expression and survival and clinicopathological characteristics of cancer patients.

METHODS

Hazard ratios for overall survival and disease-free survival with their 95% confidence intervals were used to evaluate the role of lincRNA-ROR expression in the prognosis of cancer patients. Risk ratios with their 95% confidence intervals were applied to assess the relationship between lincRNA-ROR expression and clinicopathological parameters.

RESULTS

A total of 18 articles with 1441 patients were enrolled. Our results indicated that high lincRNA-ROR expression was significant associated with tumor size, TNM stage, clinical stage, lymph metastasis, metastasis and vessel invasion of cancer patients. There were no correlations between high lincRNA-ROR expression and age, gender, infiltration depth, differentiation, serum CA19-9 and serum CEA of cancer patients. In addition, high lincRNA-ROR expression was associated with shorter Overall survival and disease-free survival on both univariate and multivariate analyses. Meanwhile, there were no obvious publication bias in our meta-analysis.

CONCLUSIONS

LincRNA-ROR expression was associated with the clinicopathological features and outcome of cancer patients, which suggested that lincRNA-ROR might serve as a potential biomarker for cancer prognosis.

ETHICAL APPROVAL

Since this study is on the basis of published articles, ethical approval and informed consent of patients are not required.

Epigenetic regulation of cancer stem cell formation and maintenance

Cancerous tumours contain a rare subset of cells with stem-like properties that are termed cancer stem cells (CSCs). CSCs are defined by their ability to divide both symmetrically and asymmetrically, to initiate new tumour growth and to tolerate the foreign niches required for metastatic dissemination. Accumulating evidence suggests that tumours arise from cells with stem-like properties, the generation of CSCs is therefore likely to be an initiatory event in carcinogenesis. Furthermore, CSCs in established tumours exist in a dynamic and plastic state, with nonstem tumour cells thought to be capable of de-differentiation to CSCs. The regulation of the CSC state both during tumour initiation and within established tumours is a desirable therapeutic target and is mediated by epigenetic factors. In this review, we will explore the epigenetic parallels between induced pluripotency and the generation of CSCs, and discuss how the epigenetic regulation of CSCs opens up novel opportunities for therapeutic intervention.

Unraveling the dark matter, long non-coding RNAs, in male reproductive diseases: A narrative review

Recent advances in human transcriptome have revealed the fundamental and functional roles of long non-coding RNA in the susceptibility to diverse diseases and pathological conditions. They participate in wide range of biological processes such as the modulating of chromatin structure, transcription, translation, and post-translation modification. In addition, based on their unique expression profiles and their association with clinical abnormalities such as those of related to male reproductive diseases, they can be used to develop therapeutic methods and biomarkers for screening of the diseases. In this study, we will review the identified lncRNAs and their molecular functions in the pathogenesis of male reproductive diseases such as prostate cancer, benign prostatic hyperplasia, prostatitis, testicular cancer, varicocele, and sperm abnormalities.

A panel of circulating long non-coding RNAs as liquid biopsy biomarkers for breast and cervical cancers

The early detection and diagnosis of cancer is critical to optimize the treatment and management of cancer patients. Typical methods such as imaging and tissue biopsy are invasive, time-consuming, and often imprecise. Thus, recent technological advances of dependable, facile, and minimally invasive collectible oncogenic biomarkers using human biofluids and secretions have been an active area of research. Recently, circulating long non-coding RNAs (lncRNAs) have been identified as promising biomarkers that fulfill many recommended properties of successful biomarkers for cancer diagnosis and prognosis. LncRNAs play essential roles in many cellular processes including DNA repair, cell proliferation, and epithelial-to-mesenchymal transition (EMT) by regulating the expression of various genes associated with cancer development and progression. Herein, we discuss the regulatory functions/pathways associated with multiple cancer-associated lncRNAs and their potential as prognostic/diagnostic markers for breast and cervical cancers. Additionally, we provide a correlation between lncRNA levels in the blood and clinicopathological data, including sensitivity, specificity, and Area Under Curve (AUC) merits of model performance value.

Advances in DNA Repair-Emerging Players in the Arena of Eukaryotic DNA Repair

Genomic DNA is constantly damaged by factors produced during natural metabolic processes as well as agents coming from the external environment. Considering such a wide array of damaging agents, eukaryotic cells have evolved a DNA damage response (DRR) that opposes the influence of deleterious factors. Despite the broad knowledge regarding DNA damage and repair, new areas of research are emerging. New players in the field of DDR are constantly being discovered. The aim of this study is to review current knowledge regarding the roles of sirtuins, heat shock proteins, long-noncoding RNAs and the circadian clock in DDR and distinguish new agents that may have a prominent role in DNA damage response and repair.

WDR7 up-regulation upon knocking down of neighboring non-coding RNA using siRNAs encapsulated in polyamidoamine dendrimers

Objective(s):

Breast cancer is the second leading cause of cancer death in females. Understanding molecular mechanisms in cancer cells compared with normal cells is crucial for diagnostic and therapeutic strategies. Long intergenic non-protein coding RNA, a regulator of reprogramming (lincRNA-RoR) is a noncoding RNA which initially was detected in induced pluripotent stem cells, and it has an important role in cell reprogramming and highly expressed in breast cancer cells. A key point in successful gene silencing is the usage of siRNA delivery system that is safe and efficient.

Materials and Methods:

In this study, the fifth-generation of PAMAM dendrimer is used as a nanocarrier for entering siRNA molecules for gene silencing of lincRNA-RoR. WDR7 is the gene encoding adjacent of lincRNA-RoR, which has an important role in apoptosis and cell cycle. Gel retardation assay was used to find the best Negative/Positive (N/P) molar charge ratio of siRNA- PAMAM transfected into MDA-MB 231 cells. MTT assay was performed 24 hr after transfection revealed the IC50 value (half maximal inhibitory concentrations) about 100 nanomolar for lincRNA-ROR siRNA.

Results:

The lincRNA-RoR and WDR7 gene expression changes were evaluated by real-time PCR after siRNA treatment and showed an increase in the gene expression of WDR7.

Conclusion:

This study showed that PAMAM dendrimer G5/ siRNA could be a useful system delivery for future gene therapy approaches.

Deciphering the Mounting Complexity of the p53 Regulatory Network in Correlation to Long Non-Coding RNAs (lncRNAs) in Ovarian Cancer

Amongst the various gynecological malignancies affecting female health globally, ovarian cancer is one of the predominant and lethal among all. The identification and functional characterization of long non-coding RNAs (lncRNAs) are made possible with the advent of RNA-seq and the advancement of computational logarithm in understanding human disease biology. LncRNAs can interact with deoxyribonucleic acid (DNA), ribonucleic acid (RNA), proteins and their combinations. Moreover, lncRNAs regulate orchestra of diverse functions including chromatin organization and transcriptional and post-transcriptional regulation. LncRNAs have conferred their critical role in key biological processes in human cancer including tumor initiation, proliferation, cell cycle, apoptosis, necroptosis, autophagy, and metastasis. The interwoven function of tumor-suppressor protein p53-linked lncRNAs in the ovarian cancer paradigm is of paramount importance. Several lncRNAs operate as p53 regulators or effectors and modulates a diverse array of functions either by participating in various signaling cascades or via interaction with different proteins. This review highlights the recent progress made in the identification of p53 associated lncRNAs while elucidating their molecular mechanisms behind the altered expression in ovarian cancer tumorigenesis. Moreover, the development of novel clinical and therapeutic strategies for targeting lncRNAs in human cancers harbors great promise.

Long non-coding RNAs as the critical factors during tumor progressions among Iranian population: an overview

BACKGROUND

Cancer is associated with various genetic and environmental risk factors. Beside the mutations or aberrant expression of protein-coding genes, the genetic deregulation of non-coding RNAs has also an important role during tumor progression and metastasis. Long non-coding RNAs (lncRNAs) are a class of ncRNAs larger than 200 nucleotides that may function as tumor-suppressor or oncogene.

MAIN BODY

There is a raising trend of cancer incidence among Iranian population during the last decades. Therefore, it is required to prepare a general population specific panel of genetic markers for the early detection of cancer in this population. The tissue-specific expression characteristics and high stability in body fluids highlight the lncRNAs as efficient diagnostic and prognostic noninvasive biomarkers in cancer. In present review we summarized all of the lncRNAs which have been reported until now in different tumors among Iranian patients.

CONCLUSIONS

This review paves the way of introducing a population based noninvasive diagnostic panel of lncRNAs for the early detection of tumor cells among Iranian population.

Parallels between artificial reprogramming and the biogenesis of cancer stem cells: Involvement of lncRNAs

Cellular identity is established and maintained by the interplay of cell type-specific transcription factors and epigenetic regulation of the genome. During development in vivo and differentiation in vitro, transitions from one cell type to the next are triggered by cell signaling events culminating in modifications of chromatin that render genes accessible or inaccessible to the transcriptional apparatus. In recent years it has become apparent that cellular identity is plastic, and technological reprogramming methods such as somatic cell nuclear transfer and induced pluripotency can yield reprogrammed cells that have been restored to a state of developmental potency. Long noncoding RNAs (lncRNAs) are untranslated functional RNA molecules that are intimately involved in the regulation of the chromatin of protein-coding genes. In fact, recent evidence shows that there are more lncRNA species in the cell than mRNA species and that most protein-coding genes are likely to be under epigenetic regulation mediated by lncRNAs. This review examines lncRNA function in reprogrammed pluripotent cells and cancer stem cells. Because cancer stem cells arise from normal cells, their biogenesis can be viewed as a reprogramming process that occurs in vivo, and parallels between artificial reprogramming and cancer stem cell biogenesis are discussed.

Regulation of DNA Double-Strand Break Repair by Non-Coding RNAs

DNA double-strand breaks (DSBs) are deleterious lesions that are generated in response to ionizing radiation or replication fork collapse that can lead to genomic instability and cancer. Eukaryotes have evolved two major pathways, namely homologous recombination (HR) and non-homologous end joining (NHEJ) to repair DSBs. Whereas the roles of protein-DNA interactions in HR and NHEJ have been fairly well defined, the functions of small and long non-coding RNAs and RNA-DNA hybrids in the DNA damage response is just beginning to be elucidated. This review summarizes recent discoveries on the identification of non-coding RNAs and RNA-mediated regulation of DSB repair.

Long noncoding RNA ROR as a novel biomarker for progress and prognosis outcome in human cancer: a meta-analysis in the Asian population

Background

Long intergenic non-protein coding RNA, a regulator of reprogramming (ROR), has been found to play an oncogene role in various human malignant tumors. This meta-analysis aimed to synthesize available data to verify the association between clinical prognosis value and ROR expression level.

Materials and methods

We performed a systematic search by using PubMed (Medline), Embase, Cochrane Library, ScienceDirect, Springer, and ISI Web of Knowledge from inception to November 15, 2017. Eleven studies with 903 patients were included in this meta-analysis according to the exclusion and inclusion criteria, and the quality of the publications was assessed by using the Newcastle-Ottawa Scale. Pooled odds ratios (OR) and hazard ratios (HR) with 95% CI were used to describe the effect.

Results

The results showed that overexpression of ROR is positively associated with lymph node metastasis (OR=4.472, 95% CI: 3.212–6.225, Z=8.87, P=0.000), tumor invasion depth (OR=9.93, 95% CI: 5.33–18.47, Z=7.24, P<0.001), TNM stage (III/IV vs I/II, OR=2.96, 95% CI: 2.18–4.02, Z=6.95, P<0.001), distant metastasis (OR=3.142, 95% CI: 2.187–4.513, Z=6.20, P<0.001) respectively. Additionally, high expression of ROR was significantly correlated with unfavorable disease-free survival (DFS) (HR=2.74, 95% CI: 1.65–3.82, Z=4.93, P=0.000) and overall survival (OS) (HR=2.09, 95% CI: 1.64–2.54, Z=9.07, P<0.001). Subgroup analysis demonstrated that neither cancer type (digestive or respiratory system) nor sample size (more or less than 100) did not alter the prognostic value of ROR. Furthermore, we performed publication bias and sensitivity analysis in order to examine the stability of meta-analysis of ROR along with OS, which showed that the shape of the funnel plot was nearly symmetrical and the resulting pattern was not significantly influenced while disconnecting each suitable study.

Conclusion

In accordance with these results, we suggested that the overexpression of long noncoding RNA ROR could act as a novel biomarker for predicting poor prognosis in different human cancers.

Non-Coding RNAs and Endometrial Cancer

Non-coding RNAs (ncRNAs) are involved in the regulation of cell metabolism and neoplastic transformation. Recent studies have tried to clarify the significance of these information carriers in the genesis and progression of various cancers and their use as biomarkers for the disease; possible targets for the inhibition of growth and invasion by the neoplastic cells have been suggested. The significance of ncRNAs in lung cancer, bladder cancer, kidney cancer, and melanoma has been amply investigated with important results. Recently, the role of long non-coding RNAs (lncRNAs) has also been included in cancer studies. Studies on the relation between endometrial cancer (EC) and ncRNAs, such as small ncRNAs or micro RNAs (miRNAs), transfer RNAs (tRNAs), ribosomal RNAs (rRNAs), antisense RNAs (asRNAs), small nuclear RNAs (snRNAs), Piwi-interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs), competing endogenous RNAs (ceRNAs), lncRNAs, and long intergenic ncRNAs (lincRNAs) have been published. The recent literature produced in the last three years was extracted from PubMed by two independent readers, which was then selected for the possible relation between ncRNAs, oncogenesis in general, and EC in particular.

Gene Expression Analysis of Two Epithelial-mesenchymal Transition-related Genes: Long Noncoding RNA-ATB and SETD8 in Gastric Cancer Tissues

Background

Cancer is the second cause of death after cardiovascular diseases worldwide. Tumor metastasis is the main cause of death in patients with cancer; therefore, unraveling the molecular mechanisms involved in metastasis is critical. Epithelial-mesenchymal transition (EMT) is believed to promote tumor metastasis. Based on the critical roles of long noncoding RNA-ATB (lncRNA-ATB) and SETD8 genes in cancer pathogenesis and EMT, in this study, we aimed to assess expression profile and clinicopathological relevance of these two genes in human gastric cancer.

Materials and Methods

Quantitative real-time polymerase chain reaction was performed to assess these gene expressions in gastric cancer tissues and various cell lines. The associations between these gene expressions and clinicopathological characteristics were also analyzed.

Results

Insignificant downregulation of lncRNA-ATB and significant upregulation of SETD8 in cancerous versus noncancerous gastric tissues were observed. Among different examined cell lines, all displayed both genes expression. Except for a significant inverse correlation between the expression levels of lncRNA-ATB and depth of invasion (T) and a direct association between SETD8 levels and advanced tumor grades, no significant association was found with other clinicopathological characteristics.

Conclusion

lncRNA-ATB and SETD8 genes may play a critical role in gastric cancer progression and may serve as potential diagnostic/prognostic biomarkers in cancer patients.

Long noncoding RNAs in gastric cancer carcinogenesis and metastasis

Recent studies of the human transcriptome, most prominently by the ENCyclopedia Of DNA Elements project, have revealed an unexpected number of noncoding RNAs (ncRNAs). Long noncoding RNAs (lncRNAs) are typically referred to a heterogeneous group of polyadenylated long ncRNAs, with a length of > 200 nt. LncRNAs constitute an integral part of tumor biology, with many lncRNAs discovered to be aberrantly expressed in various cancer types. They are involved in many aspects of cancer pathogenesis from its initiation to progression, metastasis and treatment response. Gastric cancer (GC) is the third leading cause of cancer death worldwide. Despite the current improvements of life expectancy and survival rate, most of the patients are diagnosed when their cancer has been progressed to advanced stages. Therefore, unraveling the molecular mechanisms of GC to find early-stage biomarkers is urgent. As the list of lncRNAs with deregulated expression in GC is steadily expanding, these molecules offer a source for developing GC-specific biomarkers. In this review, we will present and discuss those lncRNAs whose expression has been shown to be deregulated in GC.

LincRNA-ROR promotes metastasis and invasion of esophageal squamous cell carcinoma by regulating miR-145/FSCN1

Background and objective

In an attempt to discover a new biomarker for early diagnosis and prognosis of esophageal squamous cell carcinoma (ESCC), the regulation mechanism of large intergenic non-coding RNA–regulator of reprogramming (lincRNA-ROR) as a microRNA (miRNA) sponge was studied.

Patients and methods

ROR expression in 91 pairs of ESCC tissue samples and matched adjacent tissues was quantified with real-time fluorescent quantitative polymerase chain reaction (qRT-PCR). The ROR–miRNA–mRNA regulatory network was built with 161 esophageal cancer (EC) tissues and 11 adjacent tumor tissues from The Cancer Genome Atlas (TCGA) database. A total of 96 cases of ESCC from TCGA database were collected for analysis on survival rates. The regulatory relationship between ROR, miR-145 and FSCN1 was verified in ESCC cells via qRT-PCR, dual luciferase reporter (DLR) assay, RNA immunoprecipitation (RIP) and Western blotting. The transwell method was used to detect cell migration and invasion.

Results

ROR expression in ESCC tumor tissues was significantly higher than in the adjacent tissues, p<0.001. The survival rate of ESCC patients with high ROR expression levels was lower than that of patients with low ROR expression levels (p<0.001). ROR overexpression could downregulate miR-145 by up to 50% was proven by RIP, DLR assay, and qRT-PCR. Two effective binding sites of ROR to miR-145 were verified by DLR assay. One of the sites has never been cited in the literature. The Western blotting results showed that FSCN1 was a downstream target of ROR/miR-145 (p<0.05). Transwell assays were used to show that overexpression of ROR enhanced migration and invasion behavior of ESCC and miR-145 hindered these effects.

Conclusion

ROR acted as a competitive endogenous RNA (ceRNA) of miR-145 in ESCC. A novel, effective miR-145 binding site of ROR was discovered. The ROR/miR-145/FSCN1 pathway was shown to take part in the metastasis of ESCC. ROR is likely an oncogene biomarker for ESCC early diagnosis and prognosis.

Aberrant expression of PlncRNA-1 and TUG1: potential biomarkers for gastric cancer diagnosis and clinically monitoring cancer progression

Aim: To evaluate PlncRNA-1, TUG1 and FAM83H-AS1 gene expression and their possible role as a biomarker in gastric cancer (GC) progression. Patients & methods: Long noncoding RNA expressions and clinicopathological characteristics were assessed in 70 paired GC tissues. Furthermore, corresponding data from 318 GC patients were downloaded from The Cancer Genome Atlas database. Results: Expression of PlncRNA-1 and TUG1 were significantly upregulated in GC tumoral tissues, and significantly correlated with clinicopathological characters. However, FAM83H-AS1 showed no consistently differential expression. The expression of these three long noncoding RNAs was significantly higher in The Cancer Genome Atlas tumoral tissues. Conclusion: In conclusion, PlncRNA-1 and TUG1 genes may play a critical role in GC progression and may serve as potential diagnostic biomarkers in GC patients.

The evolving concept of cancer stem-like cells in thyroid cancer and other solid tumors

The cancer stem-like cell (CSC) hypothesis postulates that a small population of cells in a cancer has self-renewal and clonal tumor initiation properties. These cells are responsible for tumor initiation, growth, recurrence and for resistance to chemotherapy and radiation therapy. CSCs can be characterized using markers such as SSEA-1, SSEA-4, CD44, CD24, ALDEFLUOR and others. CSCs form spheres when they are cultured in serum-free condition in low attachment plates and can generate tumors when injected into immune-deficient mice. During epithelial to mesenchymal transition (EMT), cells lose cellular adhesion and polarity and acquire an invasive phenotype. Recent studies have established a relationship between EMT and increased numbers of CSCs in some solid malignancies. Non-coding RNAs such as microRNAs and long non-coding RNAs (lncRNAs) have been shown to have important roles during EMT and some of these molecules also have regulatory roles in the proliferation of CSCs. Specific lncRNAs enhanced cell migration and invasion in breast carcinomas, which was associated with the generation of stem cell properties. The tumor microenvironment of CSCs also has an important role in tumor progression. Recent studies have shown that the interaction between tumor cells and the local microenvironment at the metastatic site leads to the development of premetastatic niche(s) and allows for the proliferation of the metastatic cells during colonization. The role of exosomes in the microenvironment during the EMT program is currently a major area of research. This review examines CSCs and the relationship between EMT and CSCs in solid tumors with emphasis on thyroid CSCs. The role of non-coding RNAs and of the microenvironment in EMT and in tumor progression are also examined. This review also highlights the growing number of studies that show the close association of EMT and CSCs and the role of exosomes and other elements of the tissue microenvironment in CSC metastasis. A better understanding of these mechanisms will lead to more effective targeting of primary and metastatic malignancies.

Long Non-Coding RNAs: Key Regulators of Epithelial-Mesenchymal Transition, Tumour Drug Resistance and Cancer Stem Cells

Epithelial mesenchymal transition (EMT), the adoption by epithelial cells of a mesenchymal-like phenotype, is a process co-opted by carcinoma cells in order to initiate invasion and metastasis. In addition, it is becoming clear that is instrumental to both the development of drug resistance by tumour cells and in the generation and maintenance of cancer stem cells. EMT is thus a pivotal process during tumour progression and poses a major barrier to the successful treatment of cancer. Non-coding RNAs (ncRNA) often utilize epigenetic programs to regulate both gene expression and chromatin structure. One type of ncRNA, called long non-coding RNAs (lncRNAs), has become increasingly recognized as being both highly dysregulated in cancer and to play a variety of different roles in tumourigenesis. Indeed, over the last few years, lncRNAs have rapidly emerged as key regulators of EMT in cancer. In this review, we discuss the lncRNAs that have been associated with the EMT process in cancer and the variety of molecular mechanisms and signalling pathways through which they regulate EMT, and finally discuss how these EMT-regulating lncRNAs impact on both anti-cancer drug resistance and the cancer stem cell phenotype.

The expanding regulatory universe of p53 in gastrointestinal cancer

Tumor suppresser gene TP53 is one of the most frequently deleted or mutated genes in gastrointestinal cancers. As a transcription factor, p53 regulates a number of important protein coding genes to control cell cycle, cell death, DNA damage/repair, stemness, differentiation and other key cellular functions. In addition, p53 is also able to activate the expression of a number of small non-coding microRNAs (miRNAs) through direct binding to the promoter region of these miRNAs.  Many miRNAs have been identified to be potential tumor suppressors by regulating key effecter target mRNAs. Our understanding of the regulatory network of p53 has recently expanded to include long non-coding RNAs (lncRNAs). Like miRNA, lncRNAs have been found to play important roles in cancer biology.  With our increased understanding of the important functions of these non-coding RNAs and their relationship with p53, we are gaining exciting new insights into the biology and function of cells in response to various growth environment changes. In this review we summarize the current understanding of the ever expanding involvement of non-coding RNAs in the p53 regulatory network and its implications for our understanding of gastrointestinal cancer.