Long non-coding RNA ZNFX1-AS1 promotes the tumor progression and metastasis of colorectal cancer by acting as a competing endogenous RNA of miR-144 to regulate EZH2 expression

Unraveling the ncRNA landscape that governs colorectal cancer: A roadmap to personalized therapeutics

Colorectal cancer (CRC) being one of the most common malignancies, has a significant death rate, especially when detected at an advanced stage. In most cases, the fundamental aetiology of CRC remains unclear despite the identification of several environmental and intrinsic risk factors. Numerous investigations, particularly in the last ten years, have indicated the involvement of epigenetic variables in this type of cancer. The development, progression, and metastasis of CRC are influenced by long non-coding RNAs (lncRNAs), which are significant players in the epigenetic pathways. LncRNAs are implicated in diverse pathological processes in CRC, such as liver metastasis, epithelial to mesenchymal transition (EMT), inflammation, and chemo-/radioresistance. It has recently been determined that CRC cells and tissues exhibit dysregulation of tens of oncogenic and tumor suppressor lncRNAs. Serum samples from CRC patients exhibit dysregulated expressions of several of these transcripts, offering a non-invasive method of detecting this kind of cancer. In this review, we outlined the typical paradigms of the deregulated lncRNA which exert significant role in the underlying molecular mechanisms of CRC initiation and progression. We comprehensively discuss the role of lncRNAs as innovative targets for CRC prognosis and treatment.

Long noncoding RNA ZFAS1 exerts a suppressive impact on ferroptosis by modulating the miR-150/AIFM2 axis in hepatocellular carcinoma cells

ZNFX1 Antisense RNA 1 (ZFAS1) act as an oncogenic long noncoding RNA in multiple types of cancer. Ferroptosis is an iron-dependent cell death characterized by excessive iron accumulation and lipid peroxidation. However, to date, the functional role and mechanism of ZFAS1 in ferroptosis in hepatocellular carcinoma (HCC) remains largely unknown. The present study revealed that ZFAS1 was upregulated in HCC and upregulation of ZFAS1 indicated poor clinical outcome of HCC patients. Loss- and gain-of-function experiments demonstrated that knockdown of ZFAS1 inhibited HCC cell proliferation and induced ferroptosis, while overexpression of ZFAS1 exerted opposite effects. ZFAS1 enhanced cell proliferation via suppression of ferroptotic death. Mechanistically, ZFAS1 interacted with miR-150 and decreased its expression. AIFM2, the critical ferroptosis protector, was a direct target of ZFAS1/miR-150. ZFAS1 accelerated HCC proliferation and inhibited ferroptosis by the regulation of the miR-150/AIFM2 axis. These discoveries intimate an essential part of ZFAS1/miR-150/AIFM2 in governing HCC ferroptosis, which may provide a promising therapeutic strategy for HCC patients.

Genome-wide association studies and Mendelian randomization analyses provide insights into the causes of early-onset colorectal cancer

BACKGROUND

The incidence of early-onset colorectal cancer (EOCRC; diagnosed <50 years of age) is rising globally; however, the causes underlying this trend are largely unknown. CRC has strong genetic and environmental determinants, yet common genetic variants and causal modifiable risk factors underlying EOCRC are unknown. We conducted the first EOCRC-specific genome-wide association study (GWAS) and Mendelian randomization (MR) analyses to explore germline genetic and causal modifiable risk factors associated with EOCRC.

PATIENTS AND METHODS

We conducted a GWAS meta-analysis of 6176 EOCRC cases and 65 829 controls from the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), the Colorectal Transdisciplinary Study (CORECT), the Colon Cancer Family Registry (CCFR), and the UK Biobank. We then used the EOCRC GWAS to investigate 28 modifiable risk factors using two-sample MR.

RESULTS

We found two novel risk loci for EOCRC at 1p34.1 and 4p15.33, which were not previously associated with CRC risk. We identified a deleterious coding variant (rs36053993, G396D) at polyposis-associated DNA repair gene MUTYH (odds ratio 1.80, 95% confidence interval 1.47-2.22) but show that most of the common genetic susceptibility was from noncoding signals enriched in epigenetic markers present in gastrointestinal tract cells. We identified new EOCRC-susceptibility genes, and in addition to pathways such as transforming growth factor (TGF) β, suppressor of Mothers Against Decapentaplegic (SMAD), bone morphogenetic protein (BMP) and phosphatidylinositol kinase (PI3K) signaling, our study highlights a role for insulin signaling and immune/infection-related pathways in EOCRC. In our MR analyses, we found novel evidence of probable causal associations for higher levels of body size and metabolic factors-such as body fat percentage, waist circumference, waist-to-hip ratio, basal metabolic rate, and fasting insulin-higher alcohol drinking, and lower education attainment with increased EOCRC risk.

CONCLUSIONS

Our novel findings indicate inherited susceptibility to EOCRC and suggest modifiable lifestyle and metabolic targets that could also be used to risk-stratify individuals for personalized screening strategies or other interventions.

The prognostic, diagnostic, and therapeutic impact of Long noncoding RNAs in gastric cancer

Gastric cancer (GC), ranking as the third deadliest cancer globally, faces challenges of late diagnosis and limited treatment efficacy. Long non-coding RNAs (lncRNAs) emerge as valuable treasured targets for cancer prognosis, diagnosis, and therapy, given their high specificity, convenient non-invasive detection in body fluids, and crucial roles in diverse physiological and pathological processes. Research indicates the significant involvement of lncRNAs in various aspects of GC pathogenesis, including initiation, metastasis, and recurrence, underscoring their potential as novel diagnostic and prognostic biomarkers, as well as therapeutic targets for GC. Despite existing challenges in the clinical application of lncRNAs in GC, the evolving landscape of lncRNA molecular biology holds promise for advancing the survival and treatment outcomes of gastric cancer patients. This review provides insights into recent studies on lncRNAs in gastric cancer, elucidating their molecular mechanisms and exploring the potential clinical applications in GC.

YY1-induced lncRNA00511 promotes melanoma progression via the miR-150-5p/ADAM19 axis

Increasing evidence indicates that long noncoding RNAs (lncRNAs) are therapeutic targets and key regulators of tumors development and progression, including melanoma. Long intergenic non-protein-coding RNA 511 (LINC00511) has been demonstrated as an oncogenic molecule in breast, stomach, colorectal, and lung cancers. However, the precise role and functional mechanisms of LINC00511 in melanoma remain unknown. This study confirmed that LINC00511 was highly expressed in melanoma cells (A375 and SK-Mel-28 cells) and tissues, knockdown of LINC00511 could inhibit melanoma cell migration and invasion, as well as the growth of subcutaneous tumor xenografts in vivo. By using Chromatin immunoprecipitation (ChIP) assay, it was demonstrated that the transcription factor Yin Yang 1 (YY1) is capable of binding to the LINC00511 promoter and enhancing its expression in cis. Further mechanistic investigation showed that LINC00511 was mainly enriched in the cytoplasm of melanoma cells and interacted directly with microRNA-150-5p (miR-150-5p). Consistently, the knockdown of miR-150-5p could recover the effects of LINC00511 knockdown on melanoma cells. Furthermore, ADAM metallopeptidase domain expression 19 (ADAM19) was identified as a downstream target of miR-150-5p, and overexpression of ADAM19 could promote melanoma cell proliferation. Rescue assays indicated that LINC00511 acted as a competing endogenous RNA (ceRNA) to sponge miR-150-5p and increase the expression of ADAM19, thereby activating the PI3K/AKT pathway. In summary, we identified LINC00511 as an oncogenic lncRNA in melanoma and defined the LINC00511/miR-150-5p/ADAM19 axis, which might be considered a potential therapeutic target and novel molecular mechanism the treatment of patients with melanoma.

Identification of biomarkers of hepatocellular carcinoma gene prognosis based on the immune-related lncRNA signature of transcriptome data

BACKGROUND

Long non-coding RNAs (lncRNAs) are well established to have an important role in cancer. The goal of this research was to investigate the prognostic usefulness of putative immune-related lncRNAs in hepatocellular carcinoma (HCC).

METHODS

The developed lncRNA signature was validated using 343 HCC patients from The Cancer Genome Atlas (TCGA) and 81 samples from Gene Expression Omnibus (GEO). Cox regression and Least Absolute Shrinkage and Selection Operator (LASSO) analysis were used to analyze immune-related lncRNAs for HCC prognosis. Patients in the low-risk group survived substantially longer than those in the high-risk group (P < 0.05). The discovered signal might be a useful prognostic factor for predicting patient survival. Overall survival predicted some clinical net improvements, according to the nomogram. Numerous enrichment approaches (including gene set enrichment analysis) were utilized to investigate the underlying mechanisms.

RESULTS

Drug metabolism, mTOR, and p53 signaling pathways were associated with high-risk groups. When the expression of lncRNA PRRT3-AS1 was silenced in HepG2 cells, the proliferation, migration, and invasion abilities of HepG2 cells were decreased, and apoptosis was enhanced. In the supernatant from HepG2 cells with PRRT3-AS1 knockdown, the anti-inflammatory factors IL-10 and TGF-1 were induced, whereas the pro-inflammatory factors IL-1β, TNF-α, and IL-6 were reduced (P < 0.05). After PRRT3-AS1 knockdown, the protein expression of CD24, THY1, LYN, CD47, and TRAF2 in HepG2 cells was attenuated (P < 0.05).

CONCLUSION

The discovery of five immune-related lncRNA signatures has significant therapeutic significance for predicting patient prognosis and directing personalized treatment for patients with HCC, which requires additional prospective confirmation.

LncRNA DUXAP8 induces breast cancer radioresistance by modulating the PI3K/AKT/mTOR pathway and the EZH2-E-cadherin/RHOB pathway

Radiation resistance poses a major clinical challenge in breast cancer (BC) treatment, but little is known about how long noncoding RNA (lncRNA) may regulate this phenomenon. Here, we reported that DUXAP8 was highly expressed in radioresistant BC tissues, and high expression of DUXAP8 was associated with poor prognosis. We found that the overexpression of DUXAP8 promoted radioresistance, while the knockdown of DUXAP8 expression increased radiosensitivity. Further studies revealed that DUXAP8 enhanced the radioresistance of BC cells by activating the PI3K/AKT/mTOR pathway and by repressing the expression of E-cadherin and RHOB through interaction with EZH2. Together, our work demonstrates that the overexpression of DUXAP8 promotes the resistance of BC cells toward radiation through modulating PI3K/AKT/mTOR pathway and EZH2-E-cadherin/RHOB axis. Targeting DUXAP8 may serve as a potential strategy to overcome radioresistance in BC treatment.

Endothelial derived miRNA-9 mediated cardiac fibrosis in diabetes and its regulation by ZFAS1

Diabetic cardiomyopathy (DCM) is one of the most prevalent causes of morbidity and mortality in diabetic patients. Hyperglycemia induces increased expression/deposition of extracellular matrix (ECM) proteins including fibronectin (FN) and collagen (Col) and plays an important role in fibrosis in diabetic cardiomyopathy (DCM). The roles of RNAs including microRNA (miRNA) and long non-coding RNAs (lncRNA) have begun to be understood in many conditions. In this study, we investigated the role of a specific miRNA, miR-9, and its interactions with lncRNA ZFAS1 in mediating fibrosis in DCM. Treatment with 25 mM glucose (HG) decreased miR-9 expression and increased expressions of ZFAS1, ECM proteins and inflammatory markers, compared to 5 mM glucose (NG) in the HCMECs by using qRT-PCR. Glucose-induced upregulation of ECM proteins can be prevented by ZFAS1 siRNA or miR-9 mimic transfection. Luciferase assay was confirmed miR-9 binding to FN 3’-UTR. miR-9 expression can be regulated by ZFAS1 through polycomb repressive complex 2 (PRC2) components using RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) assays. In the in vivo experiment, hyperglycemia-induced the ECM production can be prevented by the miR-9 overexpression in the fibrosis in DCM. These studies showed a novel glucose-induced molecular mechanism in which ZFAS1 participates in the transcriptional regulation of ECM protein production in diabetes through miR-9.

The role of epigenetic modifications in Colorectal Cancer Metastasis

Distant metastasis is the major contributor to the high mortality rate of colorectal cancer (CRC). To overcome the poor prognosis caused by distant metastasis, the mechanisms of CRC metastasis should be further explored. Epigenetic events are the main mediators of gene regulation and further affect tumor progression. Recent studies have found that some epigenetic enzymes are often dysregulated or mutated in multiple tumor types, which prompted us to study the roles of these enzymes in CRC metastasis. In this review, we summarized the alteration of enzymes related to various modifications, including histone modification, nonhistone modification, DNA methylation, and RNA methylation, and their epigenetic mechanisms during the progression of CRC metastasis. Existing data suggest that targeting epigenetic enzymes is a promising strategy for the treatment of CRC metastasis.

lncRNA ITGB8-AS1 functions as a ceRNA to promote colorectal cancer growth and migration through integrin-mediated focal adhesion signaling

Long non-coding RNAs (lncRNAs) play critical roles in tumorigenesis and progression of colorectal cancer (CRC). However, functions of most lncRNAs in CRC and their molecular mechanisms remain uncharacterized. Here we found that lncRNA ITGB8-AS1 was highly expressed in CRC. Knockdown of ITGB8-AS1 suppressed cell proliferation, colony formation, and tumor growth in CRC, suggesting oncogenic roles of ITGB8-AS1. Transcriptomic analysis followed by KEGG analysis revealed that focal adhesion signaling was the most significantly enriched pathway for genes positively regulated by ITGB8-AS1. Consistently, knockdown of ITGB8-AS1 attenuated the phosphorylation of SRC, ERK, and p38 MAPK. Mechanistically, ITGB8-AS1 could sponge miR-33b-5p and let-7c-5p/let-7d-5p to regulate the expression of integrin family genes ITGA3 and ITGB3, respectively, in the cytosol of cells. Targeting ITGB8-AS1 using antisense oligonucleotide (ASO) markedly reduced cell proliferation and tumor growth in CRC, indicating the therapeutic potential of ITGB8-AS1 in CRC. Furthermore, ITGB8-AS1 was easily detected in plasma of CRC patients, which was positively correlated with differentiation and TNM stage, as well as plasma levels of ITGA3 and ITGB3. In conclusion, ITGB8-AS1 functions as a competing endogenous RNA (ceRNA) to regulate cell proliferation and tumor growth of CRC via regulating focal adhesion signaling. Targeting ITGB8-AS1 is effective in suppressing CRC cell growth and tumor growth. Elevated plasma levels of ITGB8-AS1 were detected in advanced-stage CRC. Thus, ITGB8-AS1 could serve as a potential therapeutic target and circulating biomarker in CRC.

Differential Expression of Decorin in Metastasising Colorectal Carcinoma Is Regulated by miR-200c and Long Non-Coding RNAs

Decorin (DCN) is one of the matricellular proteins that participate in normal cells’ function as well as in cancerogenesis. While its expression in primary tumours is well known, there is limited data about its expression in metastases. Furthermore, the post-transcriptional regulation of DCN is still questionable, although it is well accepted that it is an important mechanism of developing metastatic cancer. The aim of our study was to analyse the expression of DCN and its potential regulatory ncRNAs in metastatic colorectal carcinoma (CRC). Nineteen patients with metastatic CRC were included. Using qPCR, we analysed the expression of DCN, miR-200c and five lncRNAs (LUCAT1, MALAT1, lncTCF7, XIST, and ZFAS1) in lymph node and liver metastases in comparison to the invasive front and central part of a primary tumour. Our results showed insignificant upregulation of DCN and significant upregulation for miR-200c, MALAT1, lncTCF7 and ZFAS1 in metastases compared to the primary tumour. miR-200c showed a positive correlation with DCN, and the aforementioned lncRNAs exhibited a significant positive correlation with miR-200c expression in metastatic CRC. Our results suggest that DCN as well as miR-200c, MALAT1, lncTCF7 and ZFAS1 contribute to the development of metastases in CRC and that regulation of DCN expression in CRC by ncRNAs is accomplished in an indirect manner.

The Relationship Between the Network of Non-coding RNAs-Molecular Targets and N6-Methyladenosine Modification in Colorectal Cancer

Recent accumulating researches implicate that non-coding RNAs (ncRNAs) including microRNA (miRNA), circular RNA (circRNA), and long non-coding RNA (lncRNAs) play crucial roles in colorectal cancer (CRC) initiation and development. Notably, N6-methyladenosine (m⁶A) methylation, the critical posttranscriptional modulators, exerts various functions in ncRNA metabolism such as stability and degradation. However, the interaction regulation network among ncRNAs and the interplay with m⁶A-related regulators has not been well documented, particularly in CRC. Here, we summarize the interaction networks and sub-networks of ncRNAs in CRC based on a data-driven approach from the publications (IF > 6) in the last quinquennium (2016–2021). Further, we extend the regulatory pattern between the core m⁶A regulators and m⁶A-related ncRNAs in the context of CRC metastasis and progression. Thus, our review will highlight the clinical potential of ncRNAs and m⁶A modifiers as promising biomarkers and therapeutic targets for improving the diagnostic precision and treatment of CRC.

Non-coding RNA-associated competitive endogenous RNA regulatory networks: Novel diagnostic and therapeutic opportunities for hepatocellular carcinoma

Hepatocellular carcinoma (HCC), as the most prevalent liver malignancy, is annually diagnosed in more than half a million people worldwide. HCC is strongly associated with hepatitis B and C viral infections as well as alcohol abuse. Obesity and nonalcoholic fatty liver disease (NAFLD) also significantly enhance the risk of liver cancer. Despite recent improvements in therapeutic approaches, patients diagnosed in advanced stages show poor prognosis. Accumulating evidence provides support for the regulatory role of non-coding RNAs (ncRNAs) in cancer. There are a variety of reports indicating the regulatory role of microRNAs (miRNAs) in different stages of HCC. Long non-coding RNAs (LncRNAs) exert their effects by sponging miRNAs and controlling the expression of miRNA-targeted genes. Circular RNAs (circRNAs) perform their biological functions by acting as transcriptional regulators, miRNA sponges and protein templates. Diverse studies have illustrated that dysregulation of competing endogenous RNA networks (ceRNETs) is remarkably correlated with HCC-causing diseases such as chronic viral infections, nonalcoholic steatohepatitis and liver fibrosis/cirrhosis. The aim of the current article was to provide an overview of the role and molecular mechanisms underlying the function of ceRNETs that modulate the characteristics of HCC such as uncontrolled cell proliferation, resistance to cell death, metabolic reprogramming, immune escape, angiogenesis and metastasis. The current knowledge highlights the potential of these regulatory RNA molecules as novel diagnostic biomarkers and therapeutic targets in HCC.

Long non-coding RNA COL4A2-AS1 facilitates cell proliferation and glycolysis of colorectal cancer cells via miR-20b-5p/hypoxia inducible factor 1 alpha subunit axis

Long non-coding RNAs (lncRNAs) have critical functions in tumorigenesis and progression of colorectal cancer (CRC). The role of lncRNA COL4A2-AS1 (COL4A2-AS1) lacks system investigation. The current study comprehensively analyzed the expression, biological functions, and mechanism of COL4A2-AS1 in CRC through performing real-time quantitative PCR (RT-qPCR), Western blot, cell transfection, cell colony assay, MTT assay, flow cytometry and dual-luciferase reporter system assays. A xenograft model of CRC was constructed to further verify the function of COL4A2-AS1 in CRC progression in vivo. The data revealed an upregulated expression of COL4A2-AS1 in CRC tissues and cell lines than paired adjacent tissues and normal cell line. Silencing COL4A2-AS1 inhibited proliferation, aerobic glycolysis, and promoted apoptosis of CRC cells in vivo and in vitro. However, overexpression of COL4A2-AS1 significantly promoted CRC cell proliferation and aerobic glycolysis. In CRC cells, miR-20b-5p was sponged by COL4A2-AS1 and hypoxia-inducible factor 1 alpha subunit (HIF1A). Restoration of HIF1A expression reversed the inhibitory effects of silencing COL4A2-AS1 on aerobic glycolysis and proliferation of CRC cells. The current findings showed that COL4A2-AS1 promoted the proliferation, and aerobic glycolysis of CRC cells potentially through modulating the miR-20b-5p/HIF1A axis.

Long non-coding RNA COL4A2-AS1 facilitates cell proliferation and glycolysis of colorectal cancer cells via miR-20b-5p/hypoxia inducible factor 1 alpha subunit axis

Long non-coding RNAs (lncRNAs) have critical functions in tumorigenesis and progression of colorectal cancer (CRC). The role of lncRNA COL4A2-AS1 (COL4A2-AS1) lacks system investigation. The current study comprehensively analyzed the expression, biological functions, and mechanism of COL4A2-AS1 in CRC through performing real-time quantitative PCR (RT-qPCR), Western blot, cell transfection, cell colony assay, MTT assay, flow cytometry and dual-luciferase reporter system assays. A xenograft model of CRC was constructed to further verify the function of COL4A2-AS1 in CRC progression in vivo. The data revealed an upregulated expression of COL4A2-AS1 in CRC tissues and cell lines than paired adjacent tissues and normal cell line. Silencing COL4A2-AS1 inhibited proliferation, aerobic glycolysis, and promoted apoptosis of CRC cells in vivo and in vitro. However, overexpression of COL4A2-AS1 significantly promoted CRC cell proliferation and aerobic glycolysis. In CRC cells, miR-20b-5p was sponged by COL4A2-AS1 and hypoxia-inducible factor 1 alpha subunit (HIF1A). Restoration of HIF1A expression reversed the inhibitory effects of silencing COL4A2-AS1 on aerobic glycolysis and proliferation of CRC cells. The current findings showed that COL4A2-AS1 promoted the proliferation, and aerobic glycolysis of CRC cells potentially through modulating the miR-20b-5p/HIF1A axis.

LncRNAs Associated with Chemoradiotherapy Response and Prognosis in Locally Advanced Rectal Cancer

BACKGROUND

There are only limited studies on the long non-coding RNAs (lncRNAs) associated with neoadjuvant chemoradiotherapy (NCRT) response and prognosis of locally advanced rectal cancer (LARC) patients. This study identified lncRNAs associated with NCRT response and prognosis in CRC patients and explored their potential predictive mechanisms.

METHODS

The study subjected the LncRNA expression profiles from our previous gene chip data to LASSO and identified a four-lncRNA signature that predicted NCRT response and prognosis. A Cox regression model was subsequently performed to identify the prognostic risk factors. The function of LINC00909, the lncRNA with the most powerful predictive ability, was finally identified in vivo and in vitro using CRC cell lines.

RESULTS

A comparison of the relative lncRNA expression of NCRT-responsive and non-responsive patients revealed four hub lncRNAs: DBET, LINC00909, FLJ33534, and HSD52 with AUC = 0.68, 0.73, 0.73, and 0.70, respectively (all p < 0.05). COX regression analysis further demonstrated that DBET, LINC00909 and FLJ33534 were associated with the DFS in CRC patients. The expression of the four lncRNAs was also significant in LARC patients who had not undergone NCRT (all p < 0.05). A risk score model was subsequently constructed based on the results of the multivariate COX analysis and used to predict NCRT response and prognosis in the CRC and LARC patients. The expression and prognosis of DBET, LINC00909 and FLJ33534 in the CRC tissues were further validated in the R2 platform and Oncomine database. Notably, overexpression of the LINC00909 increased the cell line resistance to the 5-FU and radiotherapy in vivo and in vitro.

CONCLUSION

DBET, LINC00909, and FLJ33534 are potential novel biomarkers for predicting NCRT response and prognosis in CRC patients. In particular, LINC00909 is an effective oncogene in CRC that could be used as a novel therapeutic target to enhance NCRT response.

Long noncoding RNA SNHG6 promotes oesophageal squamous cell carcinoma by downregulating the miR-101-3p/EZH2 pathway

Long noncoding RNAs (LncRNAs) have been reported to play a vital role in the development of oesophageal squamous cell carcinoma (OSCC). Our previous study revealed that the significant upregulation of the LncRNA small nucleolar RNA host gene 6 (SNHG6) in OSCC promotes OSCC tumourigenesis. However, the mechanisms underlying the dynamics of SNHG6 expression in OSCC have rarely been studied. In this study, we verified the tumour-promoting effect of SNHG6 through sponging miR-101-3p, and their levels were negatively correlated in human samples of OSCC. In addition, miR-101-3p overexpression reversed the effect of SNHG6. Moreover, we confirmed that SNHG6/miR-101-3p affects OSCC by regulating the expression of the enhancer of zeste 2 (EZH2). The effect of EZH2 silencing resembled closely that of SNHG6 knockdown. EZH2 silencing inhibited the expression of protein cyclin D1 and β-catenin, but in contrast, it enhanced the expression of E-cadherin. These findings demonstrated the oncogenic role of SNHG6, which promotes OSCC progression by regulating the expression of EZH2 through its interaction with miR-101-3p. These findings may help in improving the diagnosis and treatment methods of OSCC.

Emerging Roles of LncRNAs in the EZH2-regulated Oncogenic Network

Cancer is a life-threatening disease, but cancer therapies based on epigenetic mechanisms have made great progress. Enhancer of zeste homolog 2 (EZH2) is the key catalytic component of Polycomb repressive complex 2 (PRC2) that mediates the tri-methylation of lysine 27 on histone 3 (H3K27me3), a well-recognized marker of transcriptional repression. Mounting evidence indicates that EZH2 is elevated in various cancers and associates with poor prognosis. In addition, many studies revealed that EZH2 is also involved in transcriptional repression dependent or independent of PRC2. Meanwhile, long non-coding RNAs (lncRNAs) have been reported to regulate numerous and diverse signaling pathways in oncogenesis. In this review, we firstly discuss functional interactions between EZH2 and lncRNAs that determine PRC2-dependent and -independent roles of EZH2. Secondly, we summarize the lncRNAs regulating EZH2 expression at transcription, post-transcription and post-translation levels. Thirdly, we review several oncogenic pathways cooperatively regulated by lncRNAs and EZH2, including the Wnt/β-catenin and p53 pathways. In conclusion, lncRNAs play a key role in the EZH2-regulated oncogenic network with many fertile directions to be explored.

LncRNA CASC21 induces HGH1 to mediate colorectal cancer cell proliferation, migration, EMT and stemness

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs) have been increasingly reported to serve vital parts in malignancies including CRC. Although cancer susceptibility 21 (CASC21) has been uncovered to play a part in CRC, its mechanism still needs further explanation. Thus, our study aimed to further explore the influence and mechanism of CASC21 in CRC progression. Quantitative real-time RT-PCR and western blot were performed to detect gene expression; a series of functional assays were performed to investigate the effect of CASC21 on CRC cells; in vivo tumour growth was evaluated via the nude mice xenograft model. The results revealed that CASC21 facilitated CRC cell proliferation, migration, epithelial-mesenchymal transition (EMT) and stemness. In addition, CASC21 was co-expressed with and bound to transcription factor POU5F1B (POU class 5 homeobox 1B). CASC21 recruited POU5F1B to HGH1 promoter to activate the transcription of HGH1 homolog. Also, CASC21 served as a competitive endogenous RNA (ceRNA) to up-regulate HGH1 via endogenously sponging miR-485-5p. Moreover, HGH1 overexpression counteracted the suppression of CASC21 deficiency on CRC tumour growth. In summary, our study indicated that CASC21 enhanced the expression of HGH1 to promote the malignancy of CRC by recruiting POU5F1B and sponging miR-485-5p, suggesting a key role of CASC21 in CRC progression.

Identification of prognostic alternative splicing events in sarcoma

Sarcoma is a rare malignancy with unfavorable prognoses. Accumulating evidence indicates that aberrant alternative splicing (AS) events are generally involved in cancer pathogenesis. The aim of this study was to identify the prognostic value of AS-related survival genes as potential biomarkers, and highlight the functional roles of AS events in sarcoma. RNA-sequencing and AS-event datasets were downloaded from The Cancer Genome Atlas (TCGA) sarcoma cohort and TCGA SpliceSeq, respectively. Survival-related AS events were further assessed using a univariate analysis. A multivariate Cox regression analysis was also performed to establish a survival-gene signature to predict patient survival, and the area-under-the-curve method was used to evaluate prognostic reliability. KOBAS 3.0 and Cytoscape were used to functionally annotate AS-related genes and to assess their network interactions. We detected 9674 AS events in 40,184 genes from 236 sarcoma samples, and the 15 most significant genes were then used to construct a survival regression model. We further validated the involvement of ten potential survival-related genes (TUBB3, TRIM69, ZNFX1, VAV1, KCNN2, VGLL3, AK7, ARMC4, LRRC1, and CRIP1) in the occurrence and development of sarcoma. Multivariate survival model analyses were also performed, and validated that a model using these ten genes provided good classifications for predicting patient outcomes. The present study has increased our understanding of AS events in sarcoma, and the gene-based model using AS-related events may serve as a potential predictor to determine the survival of sarcoma patients.

MicroRNA-506-3p inhibits colorectal cancer cell proliferation through targeting enhancer of zeste homologue 2

A large number of studies have shown that microRNA (miRNA) has an important relationship with the occurrence and development of colorectal cancer (CRC), but its specific molecular mechanism has not been fully elucidated. This study is to explore the influence of miR-506-3p on the malignant behavior of CRC and its underlying molecular mechanism. Our results show that miR-506-3p was lowly expressed and enhancer of zeste homologue 2 (EZH2) was highly expressed in CRC. Overexpressing miR-506-3p or silencing EZH2 inhibited CRC cell proliferation, migration and invasion and promoted apoptosis. Inhibiting miR-506-3p promoted CRC cell proliferation, migration and invasion but inhibited apoptosis. These impacts were reversed after co-transfecting si-EZH2. Further mechanism studies have shown that miR-506-3p can reduce EZH2 expression in CRC cells by binding to the 3ʹUTR end of EZH2. In summary, the results of this study show that miR-506-3p inhibited CRC progression through targeting EZH2 expression. This provides a new molecular target for the clinical treatment of CRC in the future.

ZFAS1 Promotes Colorectal Cancer Metastasis Through Modulating miR-34b/SOX4 Targeting

Colorectal cancer (CRC) belongs to one of gastric cancers that half of cases will develop metastasis, causing higher mortality or chemotherapy resistance. In the present study, the long noncoding RNA zinc finger antisense 1 (ZFAS1) was proved to have high expression level in CRC samples and in advanced stages. Additionally, it also indicated that p53 status is associated with ZFAS1 expression. Silencing ZFAS1 reduced both migration and invasion ability of DLD-1 and HCT-116 cells, which is relevant to the EMT process. In addition, it was confirmed that miR-34b, a tumor suppressor miRNA directly targeted ZFAS1 3' untranslated region (3'UTR) and inhibited ZFAS1 expression. Furthermore, miR-34b partially reversed the effect of ZFAS1 on migration and invasion ability in DLD-1 cells. Meanwhile, p53 status changes by overexpression vectors or siRNA turbulent ZFAS1 expression. Besides, it was found that in most cases, the oncogene SOX4 was directly targeted by miR-34b and positive correlated to ZFAS1 expression. Silencing ZFAS1 induced SOX4 expression in DLD-1 cells. Our data demonstrated the functions and mechanisms of ZFAS1 in CRC metastasis, illustrating miR-34b directly targets ZFAS1 and inhibits metastasis ability of CRC cells. SOX4 is also the direct downstream target of miR-34b, and silencing ZFAS1 can inhibit SOX4 though modulating miR-34b.

LINC00205 promotes malignancy in lung cancer by recruiting FUS and stabilizing CSDE1

Lung cancer (LC) is characterized by high morbidity and mortality. Numerous long noncoding RNAs (lncRNAs) have been reported to be involved in the initiation and progression of human cancers, including LC. Long intergenic non-protein coding RNA 205 (LINC00205) is identified as a novel lncRNA, which has only been unmasked to be a potential cancer promoter in hepatocellular carcinoma and pancreatic cancer. The biologic function and the molecular mechanism of LINC00205 in LC require to be investigated. In the present study, we observed the elevated expression of LINC00205 in LC tissues and cells through real-time quantitative PCR (RT-qPCR). Additionally, silencing LINC00205 inhibited LC cell growth and migration, but aggravated cell apoptosis. Moreover, we found that LINC00205 recruited FUS to maintain the mRNA stability of cold shock domain containing E1 (CSDE1) and therefore up-regulated CSDE1 expression in LC. Further, the effects of LINC00205 on LC cell proliferation, apoptosis and migration were all erased by CSDE1 overexpression. These findings demonstrated that LINC00205 facilitates malignant phenotypes in LC by recruiting FUS to stabilize CSDE1, suggesting LINC00205 as a potential target for LC therapy.

Epigenetic silencing of miR-144/451a cluster contributes to HCC progression via paracrine HGF/MIF-mediated TAM remodeling

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is among the malignancies with the highest mortality. The key regulators and their interactive network in HCC pathogenesis remain unclear. Along with genetic mutations, aberrant epigenetic paradigms, including deregulated microRNAs (miRNAs), exert profound impacts on hepatocyte transformation and tumor microenvironment remodeling; however, the underlying mechanisms are largely uncharacterized.

METHODS

We performed RNA sequencing on HCC specimens and bioinformatic analyses to identify tumor-associated miRNAs. The miRNA functional targets and their effects on tumor-infiltrating immune cells were investigated. The upstream events, particularly the epigenetic mechanisms responsible for miRNA deregulation in HCC, were explored.

RESULTS

The miR-144/miR-451a cluster was downregulated in HCC and predicted a better HCC patient prognosis. These miRNAs promoted macrophage M1 polarization and antitumor activity by targeting hepatocyte growth factor (HGF) and macrophage migration inhibitory factor (MIF). The miR-144/miR-451a cluster and EZH2, the catalytic subunit of polycomb repressive complex (PRC2), formed a feedback circuit in which miR-144 targeted EZH2 and PRC2 epigenetically repressed the miRNA genes via histone H3K27 methylation of the promoter. The miRNA cluster was coordinately silenced by distal enhancer hypermethylation, disrupting chromatin loop formation and enhancer-promoter interactions. Clinical examinations indicated that methylation of this chromatin region is a potential HCC biomarker.

CONCLUSIONS

Our study revealed novel mechanisms underlying miR-144/miR-451a cluster deregulation and the crosstalk between malignant cells and tumor-associated macrophages (TAMs) in HCC, providing new insights into HCC pathogenesis and diagnostic strategies.

LncRNA LINC00342 contributes to the growth and metastasis of colorectal cancer via targeting miR-19a-3p/NPEPL1 axis

Background

Long intergenic non-protein coding RNA 00342 (LINC00342) has been identified as a novel oncogene. However, the functional role of LINC00342 in colorectal cancer (CRC) remains unclear.

Methods

The expression of LINC00342 is detected by real-time PCR (RT-PCR) analysis. Cell proliferation, migration and invasion and xenograft model are examined to analyze the biological functions of LINC00342 in vitro and in vivo using colony formation, would healing and transwell analyses. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays are used to identify the target interactions between LINC00342, miR-19a-3p and aminopeptidase like 1 (NPEPL1).

Results

LINC00342 was highly expressed in CRC. Down-regulation of LINC00342 inhibited cell proliferation and metastasis of CRC cells. Moreover, knocking down LINC00342 inhibited the tumor growth in vivo. Mechanistic investigation revealed that LINC00342 might sponge miR-19a-3p to regulate NPEPL1 expression. Further investigation indicated that the ontogenesis facilitated by LINC00342 was inhibited due to the depletion of NPEPL1.

Conclusion

LINC00342 promotes CRC progression by competitively binding miR-19a-3p with NPEPL1.

Circ_ 0115744 acts as miR-144 sponge to promote and predict the metastasis of colorectal cancer

Colorectal cancer (CRC) is one of the most common human malignant tumors in recent years. Although multiple approaches have been developed for the diagnosis and therapy of CRC, the overall survival rates of patients with metastatic and recurrent CRC remain poor. In the present study, we used the high-throughput microarray technology to screen circular RNAs (circRNAs) as a potential fingerprint for CRC. We mainly aimed to screen potential biomarkers for liver metastasis by performing risk score analysis. We detected the upregulated expression of circ_0115744 in patients with CRC with liver metastasis (CRLM). Further investigation using a validation set indicated that circ_0115744 might be considered as a fingerprint for CRLM. Functionally, the overexpression of circ_0115744 significantly promoted the invasion of CRC cell lines, while decreased expression of circ_0115744 suppressed cell invasion in vitro. Mechanistic analysis showed that circ_0115744 acted as a competing endogenous RNA of miR-144 to diminish the repressive effect of miR-144 on its target EZH2. In conclusion, we found that increased expression of circ_0115744 could differentiate CRLM from CRC and that the newly identified circ_0115744/miR-144/EZH2 axis was involved in the progression of CRC, which might be used as a potential diagnostic and therapeutic target for patients with CRC.

Portrait of Cancer Stem Cells on Colorectal Cancer: Molecular Biomarkers, Signaling Pathways and miRNAome

Colorectal cancer (CRC) is a leading cause of cancer death worldwide, and about 20% is metastatic at diagnosis and untreatable. Increasing evidence suggests that the heterogeneous nature of CRC is related to colorectal cancer stem cells (CCSCs), a small cells population with stemness behaviors and responsible for tumor progression, recurrence, and therapy resistance. Growing knowledge of stem cells (SCs) biology has rapidly improved uncovering the molecular mechanisms and possible crosstalk/feedback loops between signaling pathways that directly influence intestinal homeostasis and tumorigenesis. The generation of CCSCs is probably connected to genetic changes in members of signaling pathways, which control self-renewal and pluripotency in SCs and then establish function and phenotype of CCSCs. Particularly, various deregulated CCSC-related miRNAs have been reported to modulate stemness features, controlling CCSCs functions such as regulation of cell cycle genes expression, epithelial-mesenchymal transition, metastasization, and drug-resistance mechanisms. Primarily, CCSC-related miRNAs work by regulating mainly signal pathways known to be involved in CCSCs biology. This review intends to summarize the epigenetic findings linked to miRNAome in the maintenance and regulation of CCSCs, including their relationships with different signaling pathways, which should help to identify specific diagnostic, prognostic, and predictive biomarkers for CRC, but also develop innovative CCSCs-targeted therapies.

Identification of LncRNAs Associated With FOLFOX Chemoresistance in mCRC and Construction of a Predictive Model

Oxaliplatin, fluorouracil plus leucovorin (FOLFOX) regimen is the first-line chemotherapy of patients with metastatic colorectal cancer (mCRC). However, studies are limited regarding long non-coding RNAs (lncRNAs) associated with FOLFOX chemotherapy response and prognosis. This study aimed to identify lncRNAs associated with FOLFOX chemotherapy response and prognosis in mCRC patients and to construct a predictive model. We analyzed lncRNA expression in 11 mCRC patients treated with FOLFOX chemotherapy before surgery (four sensitive, seven resistant) by Gene Array Chip. The top eight lncRNAs (AC007193.8, CTD-2008N3.1, FLJ36777, RP11-509J21.4, RP3-508I15.20, LOC100130950, RP5-1042K10.13, and LINC00476) for chemotherapy response were identified according to weighted correlation network analysis (WGCNA). A competitive endogenous RNA (ceRNA) network was then constructed. The crucial functions of the eight lncRNAs enriched in chemotherapy resistance were mitogen-activated protein kinase (MAPK) and proteoglycans signaling pathway. Receiver operating characteristic (ROC) analysis demonstrated that the eight lncRNAs were potent predictors for chemotherapy resistance of mCRC patients. To further identify a signature model lncRNA chemotherapy response and prognosis, the validation set consisted of 196 CRC patients from our center was used to validate lncRNAs expression and prognosis by quantitative PCR (qPCR). The expression of the eight lncRNAs expression between CRC cancerous and adjacent non-cancerous tissues was also verified in the validation data set to determine the prognostic value. A generalized linear model was established to predict the probability of chemotherapy resistance and survival. Our findings showed that the eight-lncRNA signature may be a novel biomarker for the prediction of FOLFOX chemotherapy response and prognosis of mCRC patients.

Circular RNA 0081146 facilitates the progression of gastric cancer by sponging miR-144 and up-regulating HMGB1

OBJECTIVES

Recent studies have revealed that circular RNA (circRNA) plays a pivotal role in cancer development. The study aimed to investigate the role of circ_0081146 in gastric cancer (GC).

RESULTS

Circ_0081146 was upregulated in GC tissues and cells. Patients with high expression of circ_0081146 had a significantly reduced 5-year overall survival rate. Circ_0081146 knockdown restrained the growth, migration and invasion of GC cells in vitro as well as tumorigenesis in vivo. Circ_0081146 targeted miR-144 and HMGB1 was targeted by miR-144. Circ_0081146 was negatively correlated with miR-144 expression, while positively correlated with HMGB1 expression in GC tissues. Moreover, the inhibitory effect of circ_0081146 knockdown on the progression of GC cells were reversed by silencing miR-144 or HMGB1 overexpression. Mechanically, circ_0081146 increased HMGB1 expression by targeting miR-144.

CONCLUSION

Circ_0081146 functions as an oncogene in GC to promote cell growth, migration and invasion via modulating the miR-144/HMGB1 axis.

LncRNA SNHG11 facilitates tumor metastasis by interacting with and stabilizing HIF-1α

Epigenetic alteration is one of the hallmarks of colorectal cancer (CRC). Many driver genes are regulated by DNA methylation in CRC. However, the role of DNA methylation regulating lncRNAs remain elusive. Here, we identify that SNHG11 (small nucleolar RNA host gene 11) is upregulated by promotor hypomethylation in CRC and is associated with poor prognosis in CRC patients. SNHG11 can promote CRC cell migration and metastasis under hypoxia. Interestingly, the DNA-binding motif of SNHG11 is similar to that of HIF-1α. In addition, SNHG11-associated genes are enriched with members of the HIF-1 signaling pathway in CRC. Mechanistically, SNHG11 binds to the pVHLrecognition sites on HIF-1α, thus blocking the interaction of pVHL with HIF-1α and preventing its ubiquitination and degradation. Moreover, SNHG11 upregulates the expression of HIF-1α target genes, i.e., AK4, ENO1, HK2, and Twist1. Notably, SNHG11 can bind to the HRE sites in the promoter of these genes and increase their transcription. In summary, these results identify a SNHG11/ HIF-1α axis that plays a pivotal role in tumor invasion and metastasis.

TCONS_00012883 promotes proliferation and metastasis via DDX3/YY1/MMP1/PI3K-AKT axis in colorectal cancer

Background

Long noncoding RNAs (lncRNAs) have emerged as key regulators in multiple cancers, including colorectal cancer (CRC). However, the biological functions and molecular mechanisms underlying most lncRNAs in CRC remain largely unknown.

Methods

A novel lncRNA (TCONS_00012883) was identified using RNA sequencing. The level of TCONS_00012883 expression in CRC was analyzed by qRT‐PCR. The biological functions of TCONS_00012883 in CRC were investigated by a series of in vitro and in vivo experiments: CCK8, colony formation, EdU, flow cytometric assays, transwell assays, and mouse xenograft. The molecular mechanisms of TCONS_00012883 were demonstrated by RNA pulldown, mass spectrometry analysis, RIP, coimmunoprecipitation, RNA sequencing, chromatin immunoprecipitation, and rescue experiments.

Results

Elevated expression of TCONS_00012883 was confirmed in CRC and positively associated with a poor prognosis. Functionally, gain‐ and loss‐of‐function assays indicated that TCONS_00012883 promoted proliferation and metastasis of CRC cell lines in vitro and in vivo. Mechanistically, RNA pulldown and mass spectrometry analysis showed that DEAD‐box helicase 3 (DDX3) was the protein partner of TCONS_00012883. Furthermore, RNA sequencing assay revealed that matrix metallopeptidase 1 (MMP1) was the downstream of TCONS_00012883. Intriguingly, we found that transcription factor (YY1) could serve as a bridge between TCONS_00012883, DDX3, and MMP1.

Conclusions

TCONS_00012883 significantly promoted CRC progression via the DDX3/YY1/MMP1 axis, and thus, may act as a major role in diagnosis and therapy of CRC.

RP11‑619L19.2 promotes colon cancer development by regulating the miR‑1271‑5p/CD164 axis

Colon cancer (CC) is one of the leading causes of cancer-related mortality in China and western countries. Several studies have demonstrated that long non-coding RNAs (lncRNAs) play critical roles in cancer development. However, the function of lncRNA RP11-619L19.2 in colon cancer remains unclear. The aim of the present study was to investigate the expression pattern, function and underlying mechanism of action of RP11-619L19.2 in CC development and metastasis. RP11-619L19.2 was found to be highly expressed in CC tissues and cell lines, and it was associated with advanced TNM stage and lymph node metastasis. Furthermore, knockdown of RP11-619L19.2 inhibited CC cell proliferation, migration, invasion and epithelial-to-mesenchymal transition (EMT). It was also observed that RP11-619L19.2 was reciprocally repressed by miR-1271-5p. Of note, miR-1271-5p negatively regulated CD164 expression by directly targeting the 3′-untranslated region of CD164. Overexpression of CD164 reversed the antimetastatic activity of RP11-619L19.2 knockdown in CC cells. Mechanistically, it was demonstrated that lncRNA RP11-619L19.2 played an oncogenic role and promoted CC development and metastasis by regulating the miR-1271-5p/CD164 axis and EMT. In conclusion, the findings of the present study indicated that RP11-619L19.2 regulates CD164 expression and EMT by sponging miR-1271-5p, which may provide novel targets for lncRNA-directed diagnosis and therapy for patients with CC.

Long non-coding RNA ADAMTS9-AS1 exacerbates cell proliferation, migration, and invasion via triggering of the PI3K/AKT/mTOR pathway in hepatocellular carcinoma cells

Although many long non-coding RNAs (lncRNAs) are modulators of biological events in hepatocellular carcinoma (HCC), the potential significance of most lncRNAs in HCC remains to be fully understood. The role of lncRNA ADAMTS9-AS1 in HCC was therefore determined. ADAMTS9-AS1 expression was higher in HCC cell lines compared to normal cells as determined by qPCR analyses. Furthermore, CCK-8, scratch wound healing, transwell migration, and invasion assays suggested that ADAMTS9-AS1 overexpression promoted the proliferation, migration, and invasion in MHCC97-H and HepG2 cells; ADAMTS9-AS1 knockdown showed the opposite results. Based on the results from GEO, the correlation between ADAMTS9-AS1 and PI3K/AKT/mTOR was identified. Thus, an association between ADAMTS9-AS1 and the PI3K/AKT/mTOR signaling pathway was further observed. To confirm the pathway protein levels, p-AKT, PIK3CB, and p-mTOR were selected. Western blot assays suggested that ADAMTS9-AS1 enhanced the expression levels of the three proteins. Because of their close relationship with PI3K/AKT/mTOR, apoptosis- or autophagy-related proteins were further investigated. ADAMTS9-AS1 expression was negatively related with LC3-II, BECN1, and pro-apoptotic Bax, whereas it was positively correlated SQSTM1 and anti-apoptotic Bcl-2 expression. Western blot results suggested that ADAMTS9-AS1 decreased ADAMTS9 expression. Our data revealed that ADAMTS9-AS1 contributed to proliferation, migration, and invasion in HCC cells, likely due to the activation of the PI3K/AKT/mTOR signaling pathway, to influence autophagy and apoptosis. These findings suggest that ADAMTS9-AS1 could serve as a molecular target in HCC treatment.

LncRNA PSMB8-AS1 contributes to pancreatic cancer progression via modulating miR-382-3p/STAT1/PD-L1 axis

Background

Accumulating evidence demonstrates the essential role of long non-coding RNA (lncRNA) in various types of cancers, including pancreatic cancer. However, the functions and regulation mechanism of lncRNA PMSB8-AS1 in pancreatic cancer are largely unclear.

Methods

Quantitative reverse transcription PCR (qRT-PCR) is used to examine the expression of PMSB8-AS1 in PC tissues and PC cell lines. The effect of PMSB8-AS1 on the proliferation of PC cells was detected using CCK8 assay, colony assay, and flow cytometry. The effect of PMSB8-AS1 on the migration and invasion of pancreatic cancer cells was detected using a wound-healing assay and transwell migration assay. Bioinformatic analysis, double luciferase reporting assay, western blot, and rescue experiments were used to detect the regulatory relationship between PMSB8-AS1, miR-382–3p, STAT1, and PD-L1.

Results

PMSB8-AS1 expression was upregulated in PC tissues and cell lines and positively associated with the worst survival in patients with PC. The in vitro and in vivo assays demonstrated that overexpression of PMSB8-AS1 significantly promoted pancreatic cancer cell proliferation, migration, and invasion, whereas knockdown of PMSB8-AS1 suppressed cell proliferation, migration, invasion, and EMT, and decreased apoptosis of PC cells. Besides, PMSB8-AS1 directly bound to miR-382–3p downregulated its expression. Besides, PMSB8-AS1 reversed the effect of miR-382–3p on the growth and metastasis of PC cells, which might be targeted on STAT1. Furthermore, STAT1 is the transcriptional factor that activates the expression of PD-L1.

Conclusion

lncRNA PMSB8-AS1 promotes pancreatic cancer progression via STAT1 by sponging miR-382–3p involving regulation PD-L1.

LncRNA small nucleolar RNA host gene 8 promotes cell growth and migration of osteosarcoma in vitro and in vivo by functioning as a ceRNA of microRNA-876-5p

Osteosarcoma (OS) is the most leading primary malignant tumor of the bone in adolescents and young adults worldwide. Increasing data have suggested that long non-coding RNA (lncRNA) small nucleolar RNA host gene 8 (SNHG8) plays a key role in the progression of various types of human malignancy. However, the roles and potential mechanisms of SNHG8 in OS remain unclear. In this study, we found that SNHG8 levels were obviously upregulated in OS tissues and cell lines. High expression of SNHG8 was significantly correlated with increased tumor size and advanced Enneking stage, and predicted a poor prognosis of OS patients. Functional assays revealed that SNHG8 knockdown inhibited OS cell growth and migration in vitro, and restrained tumor growth of OS in nude mice in vivo. Mechanistically, SNHG8 functioned as a competing endogenous RNA (ceRNA) of miR-876-5p in OS cells. Notably, knockdown of miR-876-5p reversed the inhibitory effects of SNHG8 inhibition on OS cell proliferation and migration. In conclusion, our study suggested that SNHG8 stimulates cell growth and migration of OS cells by functioning as a ceRNA of miR-876-5p, indicating SNHG8 may be served as a novel prognostic biomarker and therapeutic target for the treatment of OS.

lncRNA TMPO-AS1 Exerts Oncogenic Roles in HCC Through Regulating miR-320a/SERBP1 Axis

Background

Previous evidence have shown that long non-coding RNA (lncRNA) TMPO antisense RNA 1 (TMPO-AS1) is involved in the aggressiveness of several cancers. Nevertheless, the precise functions of TMOP-AS1 in hepatocellular carcinoma (HCC) are still unresolved.

Materials and Methods

The expressions of TMPO-AS1 and miR-320a were detected in HCC tissues and cells by qRT-RCR. The cell growth, migration and invasion were detected by colony formation, wound healing assay and Transwell assay, respectively. The targeting relation between miR-320a and TMPO-AS1 was predicted by bioinformatics analysis and identified by luciferase reporter gene as well as FISH assay. The expression of SERPINE1 MRNA Binding Protein 1 (SERBP1) was detected by Western blot. The growth of HCC cell was analyzed using transplanted tumor model.

Results

Currently, we revealed that TMPO-AS1 was overexpressed in clinical HCC samples and a panel of HCC cell lines. Clinically, a higher level of TMPO-AS1 was connected to the advanced stage of HCC and worse prognosis of patients. Depletion of TMPO-AS1 repressed HCC cell viability, migration ability and invasiveness. Nevertheless, upregulation of TMPO-AS1 caused opposite results. Further studies revealed that lncRNA TMPO-AS1 was largely located in the cytoplasm of HCC cell and sponge miR-320a, resulting in increasing the level of SERBP1 in HCC cell. Finally, TMPO-AS1 silencing suppressed tumor growth of HCC cell in vivo.

Conclusion

Collectively, our results suggested that TMPO-AS1 was a promoting factor for the aggressive behaviors of HCC cell.

LncPRYP4-3 serves as a novel diagnostic biomarker for dissecting subtypes of metabolic associated fatty liver disease by targeting RPS4Y2

Longitudinal studies have improved current diagnostics and management of metabolic associated fatty liver disease (MAFLD) patients by liver biopsy and therapeutic intervention, yet the deficiency of biomarker spectrum for dissecting subtypes largely hinders the symptomatic treatment. We originally enriched serum from peripheral blood of 618 healthy donors (HD) and 580 MAFLD (400 NAFL, 180 NASH) patients according to multiple clinicopathological indicators. Microarray profiling and qRT-PCR were conducted to identify lncRNAs as candidate biomarkers of MAFLD. Then, we analyzed the matching score of the indicated lncRNA with CAP or MAFLD-associated pathological parameters as well. Additionally, we took advantage of interaction network together with gene expression profiling analysis to further explore the underlying target genes of the identified lncRNA. Herein, we found CAP in nearly all of the NAFL (399/400) and NASH (179/180) patients was higher than that in the HDs (611/618). The differentially expressed lncRNAs were involved in multiple metabolic or immunologic processes by regulating MAFLD-associated pathways. Of them, serum lncPRYP4-3 was identified as a novel candidate biomarker of MAFLD, which was further confirmed by correlation analysis with clinical indicators. Thereafter, we deduced PRS4Y2 was a candidate target of lncPRYP4-3 and mediated the dysfunction in NAFL and NASH patients. Serum lncPRYP4-3 served as a novel biomarker of MAFLD and helped distinguish the subtypes and benefit precise intervention therapy. Our findings also provided overwhelming new evidence for the alteration in biological processes and gene ontology in MAFLD patients.

Comprehensive analysis of competing endogenous RNA network in Wilms tumor based on the TARGET database

Background

Wilms tumor (WT) was the most common malignant tumor of urinary system in children. With the advances in gene sequencing, research of molecular mechanism of WT tumor was gradually increasing. However, few studies have explored the influence of competing endogenous RNA (ceRNA) in WT. Accordingly, we aimed to explore the mechanisms of ceRNA co-expression network in WT.

Methods

A total of 6 non-tumor controls and 127 WT patients’ RNA-seq data combined with clinical data was acquired from Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database. Differentially expressed lncRNA, miRNA and mRNA between WT tissues and normal tissues were analyzed using “edgeR” package in R software. Weighted gene co-expression network analysis (WGCNA) was utilized to construct the ceRNA co-expression network while Molecular Complex Detection (MCODE) algorithm was used to extract the pivotal sub-network. Function annotation of mRNA was performed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Survival analysis was then conducted based on long-rank test and Kaplan-Meier curves using the survival package.

Results

By applying the “edgeR” package in R, the transcriptome expression data of 127 WT tissues with 6 normal tissues were normalized. Moreover, 146 DElncRNAs, 62 DEmiRNAs, 287 DEmRNAs of them were involved in ceRNA network after applying WGCNA. According to MCODE, we identified that the interactions between LINC002253 (lncRNA) and TRIM71 (mRNA) was mediated by hsa-mir-301a and hsa-mir-301b (miRNA). Furthermore, we detected 13 DElncRNAs which were significantly associated with the progression of WT.

Conclusions

We used WGCNA method to construct the WT ceRNA network for the first time. TRIM71 was identified to be the most closely related genes involved in hub sub-network by MCDOE, suggesting it might act as a new drug target and prognostic factor based on our comprehensive results.

LINC00961 inhibits the migration and invasion of colon cancer cells by sponging miR-223-3p and targeting SOX11

Long noncoding RNAs play essential roles in colon cancer tumorigenesis. This study aimed to explore the potential function and molecular mechanisms of LINC00961 in colon cancer. qPCR results showed that LINC00961 was downregulated in colon cancer cells and tissues. Functional assays demonstrated that LINC00961 suppressed the migration and invasion of colon cancer cells in vitro. LINC00961 functioned as an endogenous sponge for miR-223-3p in colon cancer cells. SOX11 was confirmed as a target gene of miR-223-3p. The effect of miR-223-3p on colon cancer cells was then investigated. MiR-223-3p inhibition enhanced their migration and invasion. The effect of SOX11 on colon cancer cells was studied. SOX11 overexpression inhibited the invasion of colon cancer cells. LINC00961 acted as an anti-oncogene and upregulated SOX11 expression by functioning as a miR-223-3p sponge. This research revealed the molecular mechanism of LINC00961 in colon cancer. LINC00961 might act as a potential diagnostic biomarker and therapeutic target for further clinical treatments.

Long non-coding RNA CCAT1 promotes colorectal cancer cell migration, invasiveness and viability by upregulating VEGF via negative modulation of microRNA-218

Increasing evidence has demonstrated that long non-coding (lnc) RNA is aberrantly expressed in numerous types of cancer. Colorectal cancer is a common malignancy; however, the role and mechanism underlying the influence of lncRNA-colon cancer associated transcript 1 (CCAT1) in colorectal cancer is yet to be elucidated. The present study revealed that CCAT1 is highly expressed in colorectal cancer tissues. Bioinformatics analysis and a dual-luciferase reporter gene assay indicated that CCAT1 and microRNA (miR)-218 had complementary binding sites. Furthermore, reverse transcription-quantitative PCR revealed that miR-218 was downregulated in colorectal cancer tissues compared with paired adjacent healthy tissues. To investigate the biological effects of CCAT1 on colorectal cancer cells, MTT and Transwell assays were performed. The results revealed that when compared with the control group, CCAT1-short hairpin (sh)RNA significantly inhibited colorectal cancer cell (SW480) viability and decreased migration and invasiveness. In addition, CCAT1-shRNA significantly reduced vascular endothelial growth factor (VEGF) expression in SW480 cells; however, these effects were partially rescued by an miR-218 inhibitor. Furthermore, it was revealed that the CCAT1-plasmid significantly promoted the viability of SW480 cells, increased cell migration and invasiveness, and significantly increased VEGF expression. However, these effects were also partially rescued by with a miR-218 mimic. Taken together, the present results identified that the CCAT1/miR-218 axis serves a key role in the regulation of colorectal cancer progression, which may be used as potential therapeutic target for the treatment of colorectal cancer.

Long non-coding RNA AGER-1 inhibits colorectal cancer progression through sponging miR-182

OBJECTIVE

Abundant evidence has illustrated that long non-coding RNA (lncRNA) plays a vital role in the regulation of tumor development and progression. Ectopic expression of a novel lncRNA, termed lnc-AGER-1, has been discovered in cancers, and this lncRNA was reported to exert an anti-tumor effect. However, its biological mechanism remains unelucidated in colorectal cancer.

METHODS

A total of 159 paired colorectal cancer specimens and adjacent tissues was applied to detect the expression of lnc-AGER-1 by the quantitative Real-time PCR (qRT-PCR), and a series of functional assays was executed to uncover the role of this lncRNA on colorectal cancer.

RESULTS

We found that the expression of lnc-AGER-1 in the tumor tissues was significantly down-regulated, while compared with adjacent normal tissues (0.0115 ± 0.0718 vs. 0.0347 ± 0.157; P < 0.0001). Also, lnc-AGER-1 was observably associated with clinical T status (r = -0.184, P = 0.024). Patients with advanced T status exerted a significantly lower level of lnc-AGER-1 than those with early T status (20.0% vs. 40.7%, P = 0.021). Over-expression of lnc-AGER-1 inhibited cell proliferation and migration efficiency, and induced cell cycle arrest at the G0/G1 phase, and promoted cell apoptosis. Further research proved that lnc-AGER-1 altered the expression of its neighbor gene, AGER, through acting as a competing endogenous RNA for miR-182 in colorectal cancer.

CONCLUSION

lnc-AGER-1 has a suppressive role in colorectal cancer development via modulating AGER, which may serve as a target for colorectal cancer diagnosis and treatment.

Identification of the Regulatory Role of lncRNA SNHG16 in Myasthenia Gravis by Constructing a Competing Endogenous RNA Network

Myasthenia gravis (MG) is an autoimmune disorder resulting from antibodies against the proteins at the neuromuscular junction. Emerging evidence indicates that long non-coding RNAs (lncRNAs), acting as competing endogenous RNAs (ceRNAs), are involved in various diseases. However, the regulatory mechanisms of ceRNAs underlying MG remain largely unknown. In this study, we constructed a lncRNA-mediated ceRNA network involved in MG using a multi-step computational strategy. Functional annotation analysis suggests that these lncRNAs may play crucial roles in the immunological mechanism underlying MG. Importantly, through manual literature mining, we found that lncRNA SNHG16 (small nucleolar RNA host gene 16), acting as a ceRNA, plays important roles in the immune processes. Further experiments showed that SNHG16 expression was upregulated in peripheral blood mononuclear cells (PBMCs) from MG patients compared to healthy controls. Luciferase reporter assays confirmed that SNHG16 is a target of the microRNA (miRNA) let-7c-5p. Subsequent experiments indicated that SNHG16 regulates the expression of the key MG gene interleukin (IL)-10 by sponging let-7c-5p in a ceRNA manner. Furthermore, functional assays showed that SNHG16 inhibits Jurkat cell apoptosis and promotes cell proliferation by sponging let-7c-5p. Our study will contribute to a deeper understanding of the regulatory mechanism of MG and will potentially provide new therapeutic targets for MG patients.

Long Non-coding RNA LOXL1-AS1 Drives Breast Cancer Invasion and Metastasis by Antagonizing miR-708-5p Expression and Activity

LOXL1-AS1, a recently characterized long non-coding RNA (lncRNA), has been reported to modulate tumor progression in several types of cancer. However, the expression and role of LOXL1-AS1 in breast cancer remain unclear. In this study, we sought to identify novel lncRNA regulators engaged in breast cancer metastasis. To this end, we examined 42 cancer-related lncRNAs between MCF7 (with low metastatic potential) and MDA-MB-231 (with high metastatic potential) cells. These lncRNAs have been found to affect the invasiveness of several cancer types, but they are still undefined in breast cancer. Among the 42 candidates, LOXL1-AS1 is significantly increased in MDA-MB-231 cells relative to MCF7 cells. We also show that LOXL1-AS1 is upregulated in breast cancer tissues and cells compared to noncancerous counterparts. Increased LOXL1-AS1 expression is correlated with tumor stage and lymph node metastasis in breast cancer patients. Biologically, overexpression of LOXL1-AS1 enhances and knockdown of LOXL1-AS1 suppresses breast cancer cell migration and invasion. In vivo studies demonstrate that depletion of LOXL1-AS1 inhibits breast cancer metastasis. Mechanistically, LOXL1-AS1 sponges miR-708-5p to increase nuclear factor κB (NF-κB) activity. LOXL1-AS1 can also interact with EZH2 protein to enhance EZH2-mediated transcriptional repression of miR-708-5p. Rescue experiments indicate that co-expression of miR-708-5p attenuates LOXL1-AS1-induced invasiveness in breast cancer. In addition, there is a negative correlation between LOXL1-AS1 and miR-708-5p expression in breast cancer specimens. Overall, LOXL1-AS1 upregulation facilitates breast cancer invasion and metastasis by blocking miR-708-5p expression and activity. LOXL1-AS1 serves as a potential therapeutic target for breast cancer treatment.

Long Noncoding RNA (lncRNA)-Mediated Competing Endogenous RNA Networks Provide Novel Potential Biomarkers and Therapeutic Targets for Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and has a high metastasis and reoccurrence rate. Long noncoding RNAs (lncRNAs) play an important role in CRC growth and metastasis. Recent studies revealed that lncRNAs participate in CRC progression by coordinating with microRNAs (miRNAs) and protein-coding mRNAs. LncRNAs function as competitive endogenous RNAs (ceRNAs) by competitively occupying the shared binding sequences of miRNAs, thus sequestering the miRNAs and changing the expression of their downstream target genes. Such ceRNA networks formed by lncRNA/miRNA/mRNA interactions have been found in a broad spectrum of biological processes in CRC, including liver metastasis, epithelial to mesenchymal transition (EMT), inflammation formation, and chemo-/radioresistance. In this review, we summarize typical paradigms of lncRNA-associated ceRNA networks, which are involved in the underlying molecular mechanisms of CRC initiation and progression. We comprehensively discuss the competitive crosstalk among RNA transcripts and the novel targets for CRC prognosis and therapy.

WITHDRAWN: LncRNA DSCAM-AS1 Promotes Proliferation, Migration and Invasion of Colorectal Cancer Cells via Modulating miR-144-5p/CDKL1

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LncRNA TDRG1 promotes the aggressiveness of gastric carcinoma through regulating miR-873-5p/HDGF axis

Gastric carcinoma (GC) is still one of the most common digestive system neoplasms and the primary reason for malignant cancer-associated death. Long non-coding RNAs (lncRNAs) have been reported to play critical roles in GC progression. In this study, we demonstrated that lncRNA testis development-related gene 1 (TDRG1) is markedly upregulated in clinical GC tissues and GC cells. High level of lncRNA TDRG1 correlates with the metastasis and prognosis of patients with GC. Overexpression of lncRNA TDRG1 promotes GC growth and metastatic-related traits in vitro and in vivo, and silencing TDRG1 causes opposite results. We future find that TDRG1 is inversely associated with miR-873-5p and positively modulates the expression of hepatoma-derived growth factor (HDGF), a functional target gene of miR-873-5p. Finally, lncRNA TDRG1 regulates the progression of GC through regulating miR-873-5p/HDGF pathway. Taken together, our data uncover the crucial function of TDRG1-miR-873-5p-HDGF axis in human gastric cancer.

The emerging role of microRNAs and long noncoding RNAs in drug resistance of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide and the second most lethal human cancer. A portion of patients with advanced HCC can significantly benefit from treatments with sorafenib, adriamycin, 5-fluorouracil and platinum drugs. However, most HCC patients eventually develop drug resistance, resulting in a poor prognosis. The mechanisms involved in HCC drug resistance are complex and inconclusive. Human transcripts without protein-coding potential are known as noncoding RNAs (ncRNAs), including microRNAs (miRNAs), small nucleolar RNAs (snoRNAs), long noncoding RNAs (lncRNAs) and circular RNA (circRNA). Accumulated evidences demonstrate that several deregulated miRNAs and lncRNAs are important regulators in the development of HCC drug resistance which elucidates their potential clinical implications. In this review, we summarized the detailed mechanisms by which miRNAs and lncRNAs affect HCC drug resistance. Multiple tumor-specific miRNAs and lncRNAs may serve as novel therapeutic targets and prognostic biomarkers for HCC.