UCA1 promotes cell proliferation and invasion of gastric cancer by targeting CREB1 sponging to miR-590-3p

LncRNA UCA1 promotes vasculogenic mimicry by targeting miR-1-3p in gastric cancer

Long noncoding RNA urothelial carcinoma-associated 1 (UCA1) has been implicated in several tumors. UCA1 promotes cell proliferation, migration, and invasion of gastric cancer (GC) cells, but the molecular mechanism has not been fully elucidated. This study revealed the oncogenic effects of UCA1 on cell growth and invasion. Furthermore, UCA1 expression was significantly correlated with the overall survival of GC patients, and the clinicopathological indicators, including tumor size, depth of invasion, lymph node metastasis, and TNM stage. Additionally, miR-1-3p was identified as a downstream target of UCA1, which was negatively regulated by UCA1. MiR-1-3p inhibited cell proliferation and vasculogenic mimicry (VM), and induced cell apoptosis by upregulating BAX, BAD, and tumor suppressor TP53 expression levels. Moreover, miR-1-3p almost completely reversed the oncogenic effect caused by UCA1, including cell growth, migration, and VM formation. This study also confirmed that UCA1 promoted tumor growth in vivo. In this study, we also revealed the correlation between UCA1 and VM formation, which is potentially crucial for tumor metastasis. Meanwhile, its downstream target miR-1-3p inhibited VM formation in GC cells. In summary, these findings indicate that the UCA1/miR-1-3p axis is a potential target for GC treatment.

Progress of Exosomal LncRNAs in Pancreatic Cancer

Pancreatic cancer is a prevalent malignant tumor with rising medication resistance and mortality. Due to a dearth of specific and trustworthy biomarkers and therapeutic targets, pancreatic cancer early detection and treatment are still not at their best. Exosomal LncRNAs have been found to be plentiful and persistent within exosomes, and they are capable of functioning whether the exosomes are traveling to close or distant cells. Furthermore, increasing evidence suggests that exosomal LncRNA, identified as an oncogene or tumor suppressor-control the growth, metastasis, and susceptibility of pancreatic cancer to chemotherapy and radiation therapy. Promising prospects for both antitumor targets and diagnostic biomarkers are exosomal LncRNAs. The primary features of exosomal LncRNAs, their biological roles in the onset and progression of pancreatic cancer, and their potential as therapeutic targets and diagnostic molecular markers are outlined in this review.

Exosomal lncRNA XIST promotes perineural invasion of pancreatic cancer cells via miR-211-5p/GDNF

Perineural invasion (PNI) is an essential form of tumor metastasis in multiple malignant cancers, such as pancreatic cancer, prostate cancer, and head and neck cancer. Growing evidence has revealed that pancreatic cancer recurrence and neuropathic pain positively correlate with PNI. Therefore, targeting PNI is a proper strategy for pancreatic cancer treatment. Exosomal lncRNA derived from pancreatic cancer cells is an essential component of the tumor microenvironment. However, whether exosomal lncXIST derived from pancreatic cancer cells can promote PNI and its exact mechanism remains to be elucidated. We show that lncXIST mediates nerve-tumor crosstalk via exosomal delivery. Our data reveal that exosomal lncXIST derived from pancreatic cancer cells is delivered to neural cells and promotes their release of glial-cell-line-derived neurotrophic factor (GDNF), essential in facilitating the PNI of pancreatic cancer. Mechanistically, microRNA-211-5p negatively regulates GDNF, and lncXIST serves as a miR-211-5p sponge. The function of exosomes in the dynamic interplay between nerves and cancer is confirmed in both in vivo and in vitro PNI models. Therefore, targeting pancreatic cancer cell-derived exosomal lncXIST may provide clues for a promising approach for developing a new strategy to combat PNI of pancreatic cancer.

The CREB1/WNK1 axis promotes the tumorigenesis of ovarian cancer via regulating HIF-1

The aim of this study was to explore the functions and molecular mechanisms of the WNK lysine deficient protein kinase 1 (WNK1) in the development of ovarian cancer. Firstly, loss- and gain-of-function assays were carried out and subsequently cell proliferation, apoptosis, invasion and migration were detected. Furthermore, WNK1 action on glucose uptake, lactate production and adenosine triphosphate (ATP) level were assessed. The roles of WNK1 on cisplatin resistance were explored using CCK-8, colony formation, and flow cytometry in vitro. Immunohistochemistry, Western blot and qRT-PCR were conducted to determine the protein and mRNA expression. Additionally, tumor growth in vivo was also monitored. We found that the overexpression of WNK1 predicted a bad prognosis of ovarian cancer patients. WNK1 enhanced the malignant behavior and facilitated glycolysis of ovarian cancer cells. Moreover, WNK1 increased cisplatin resistance in ovarian cancer cells. Mechanistically, we found that WNK1 expression was promoted by CREB1 at the transcriptional level. And CREB1 could facilitate ovarian cancer cells malignant behavior through target upregulating WNK1. Besides, we also showed that WNK1 facilitated the malignant behavior by accelerating HIF-1 expression. In xenograft tumor tissues, the downregulation of WNK1 significantly reduced HIF-1α expression. These data demonstrated that the CREB1/WNK1 axis could promote the tumorigenesis of ovarian cancer via accelerating HIF-1 expression, suggesting that the CREB1/WNK1 axis could be a potential target during the therapy of ovarian cancer.

Decoding the regulatory landscape of lncRNAs as potential diagnostic and prognostic biomarkers for gastric and colorectal cancers

Colorectal cancer (CRC) and gastric cancer (GC) are major contributors to cancer-related mortality worldwide. Despite advancements in understanding molecular mechanisms and improved drug treatments, the overall survival rate for patients remains unsatisfactory. Metastasis and drug resistance are major challenges contributing to the high mortality rate in both CRC and GC. Recent research has shed light on the role of long noncoding RNAs (lncRNAs) in the development and progression of these cancers. LncRNAs regulate gene expression through various mechanisms, including epigenetic modifications and interactions with microRNAs (miRNAs) and proteins. They can serve as miRNA precursors or pseudogenes, modulating gene expression at transcriptional and post-transcriptional levels. Additionally, circulating lncRNAs have emerged as non-invasive biomarkers for the diagnosis, prognosis, and prediction of drug therapy response in CRC and GC. This review explores the intricate relationship between lncRNAs and CRC/GC, encompassing their roles in cancer development, progression, and chemoresistance. Furthermore, it discusses the potential of lncRNAs as therapeutic targets in these malignancies. The interplay between lncRNAs, miRNAs, and tumor microenvironment is also highlighted, emphasizing their impact on the complexity of cancer biology. Understanding the regulatory landscape and molecular mechanisms governed by lncRNAs in CRC and GC is crucial for the development of effective diagnostic and prognostic biomarkers, as well as novel therapeutic strategies. This review provides a comprehensive overview of the current knowledge and paves the way for further exploration of lncRNAs as key players in the management of CRC and GC.

Circulating LncRNAs landscape as potential biomarkers in breast cancer

BACKGROUND

In Iran, the delay in diagnosis and treatment of breast cancer results in low survival rates.

AIM

It is essential to characterize new therapeutic targets and prognostic breast cancer biomarkers. The rising evidence suggested that long non-coding RNAs (lncRNAs) expression levels are deregulated in human cancers and can use as biomarkers for the rapid diagnosis of breast cancer.

METHODS

In the present study, a quantitative real-time polymerase chain reaction (qRT-PCR) technique was used to measure 20 oncogenic and tumor suppressor lncRNAs expression levels in whole blood samples of female breast cancer patients and healthy women. Receiver operating characteristic curve (ROC) was used to assess the diagnostic value of each selected lncRNA as a biomarker.

RESULTS

The results revealed that some circulating lncRNAs (MEG3, NBAT1, NKILA, GAS5, EPB41L4A-AS2, Z38, and BC040587) were significantly down-regulated in breast cancer patients compared to healthy women. In contrast, other circulating lncRNAs (H19, SPRY4-IT1, XIST, UCA1, AC026904.1, CCAT1, CCAT2, ITGB2-AS, and AK058003) were significantly up-regulated in breast cancer patients compared to controls. It was shown that the expression levels of NKILA, and NBAT1 lncRNAs were related to tumor size, and BC040587 expression level related to age, node metastasis, tumor size, and grade (p < .05). The association between H19 and SPRY4-IT1 lncRNAs with HER-2 was confirmed statistically (p < .05). ROC curves illustrated that the blood levels of SPRY4-IT1, XIST, and H19 lncRNAs have excellent potential in discriminating breast cancer from the healthy controls, showing an AUC of 1.0 (95% CI 1.0-1.0, p = .00), 0.898 (95% CI 0.815-0.981, p = .00), and 0.848 (95% CI 0.701-0.995, p = .01), respectively.

CONCLUSION

In conclusion, the expression levels of circulating H19 and SPRY4-IT1 lncRNAs in breast cancer patients could consider as the prognostic biomarkers and therapeutic targets in breast cancer, because of their excellent power in discriminating breast cancer from healthy individuals and the significant correlation of H19, and SPRY4-IT1 lncRNAs with clinicopathological traits. We also suggest the possible application of BC040587 lncRNA as a diagnostic and prognostic indicator to assess tumor progression in case of verification in larger patients' cohorts.

Exosomal ncRNAs facilitate interactive 'dialogue' between tumor cells and tumor-associated macrophages

As a biological carrier, exosomes participate in the communication between various kinds of cells, and can mediate the interactive 'dialogue' between tumor cells and tumor-associated macrophages (TAMs). TAMs are the most abundant cell population in the tumor stroma and are an important part of the tumor immune microenvironment. Various stimulating factors in the tumor microenvironment influence the polarization of TAMs into multiple phenotypes, such as M1 and M2. It plays a dual role in tumor immunity by both promoting and inhibiting tumor growth. Exosome-encapsulated non-coding RNAs (ncRNAs) participate in the interactive 'dialogue' between exosome-mediated TAMs and tumor cells. Tumor-derived exosomal ncRNAs can promote macrophage polarization, whereas exosomal ncRNAs derived from TAMs can affect tumor proliferation, metastasis, angiogenesis, and chemotherapy resistance. The present review summarizes the dual effects of exosomal ncRNAs on tumor cells and TAMs, and discusses the application of exosomal ncRNAs as a potential diagnostic or prognostic marker and drug delivery system, to provide a new perspective and potential therapeutic drugs on targeting exosomes and macrophages in the treatment of tumors.

IGF2BP1-regulated expression of ERRα is involved in metabolic reprogramming of chemotherapy resistant osteosarcoma cells

Doxorubicin (Dox) is the standard treatment approach for osteosarcoma (OS), while acquired drug resistance seriously attenuates its treatment efficiency. The present study aimed to investigate the potential roles of metabolic reprogramming and the related regulatory mechanism in Dox-resistant OS cells. The results showed that the ATP levels, lactate generation, glucose consumption and oxygen consumption rate were significantly increased in Dox-resistant OS cells compared with parental cells. Furthermore, the results revealed that the increased expression of estrogen-related receptor alpha (ERRα) was involved in metabolic reprogramming in chemotherapy resistant OS cells, since targeted inhibition of ERRα restored the shifting of metabolic profiles. Mechanistic analysis indicated that the mRNA stability, rather than ERRα transcription was markedly increased in chemoresistant OS cells. Therefore, it was hypothesized that the 3ʹ-untranslated region of ERRα mRNA was methylated by N⁶-methyladenine, which could further recruit insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) to suppress mRNA decay and increase mRNA stability. IGF2BP1 knockdown downregulated ERRα and reversed the metabolic alteration of resistant OS cells. Additionally, the oncogenic effect of the IGF2BP1/ERRα axis on Dox-resistant OS cells was verified by in vitro and in vivo experiments. Clinical analysis also revealed that the expression levels of IGF2BP1 and ERRα were associated with the clinical progression of OS. Collectively, the current study suggested that the IGF2BP1/ERRα axis could regulate metabolic reprogramming to contribute to the chemoresistance of OS cells.

CREB1 promotes proliferation and differentiation by mediating the transcription of CCNA2 and MYOG in bovine myoblasts

The cAMP response element binding protein 1 (CREB1) is an important nuclear transcription factor in eukaryotes. To explore the potential role of CREB1 on Qinchuan bovine skeletal myoblasts, we investigated the function of CREB1 on proliferation and differentiation. In this study, we found that CREB1 promoted cell proliferation by promoting DNA synthesis in S phase and cell division in G2 phase and promoted myogenic differentiation process in bovine myoblasts. Through dual luciferase experiments, we found that CREB1 can bind to the proximal promoter regions of CCNA2 and MyoG, indicating that CREB1 can play a positive regulatory role in the proliferation and differentiation of myoblasts by mediating the transcription of CCNA2 and MyoG. In addition, through downstream target gene analysis and transcriptome sequencing, we found that CREB1 plays a role in cell proliferation, myogenic differentiation, skeletal muscle repair and other related pathways.

Construction of a Prognostic Immune-Related LncRNA Risk Model for Gastric Cancer

Gastric cancer (GC) is one of the most common malignancies, and novel prognostic biomarkers for it are urgently required. This study is aimed at screening a group of immune-related lncRNAs (IRLs) in predicting the prognosis of GC patients. Genetic and clinical information from the 360 GC patients was included in this study. Eight IRLs in lncRNA-miRNA-mRNA network were screened out according to differential expression analysis. A novel risk score model with three IRLs (MIR4435-1HG, UCA1, and RP11-617F23.1) were identified, and patients were assigned to a high-risk group and a low-risk group. Patients in the low-risk group had a better prognosis. In addition, two nomograms were developed to predict the prognosis of GC. We evaluated the correlation between IRLs and the immune infiltration level of GC using TIMER. Furthermore, we verified that RP11-617F23.1 was significantly upregulated in human GC tissues compared with their adjacent tissues. And, patients with high RP11-617F23.1 expression in tumor tissues had poorer survival. In conclusion, we established a novel risk model based on IRLs for predicting the prognosis of GC. Meanwhile, a novel IRL, RP11-617F23.1, could serve as a predictor of prognosis for patients with GC.

Long non-coding RNA profiles in plasma exosomes of patients with gastric high-grade intraepithelial neoplasia

Long non-coding (lnc) RNAs in circulating exosomes are a new class of promising cancer biomarkers; however, their expression in exosomes derived from gastric high-grade intraepithelial neoplasia (GHGIN) has not been reported. In the present study, differentially expressed (DE) lncRNAs were analyzed in the peripheral blood collected from 5 patients with GHGIN and 5 healthy donors using high-throughput sequencing. Reverse transcription-quantitative PCR analysis was performed on 6 randomly selected DE lncRNAs to validate the reliability of the sequencing results. The potential roles of the DE lncRNAs in GHGIN were investigated using Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway enrichment analyses. A total of 25,145 lncRNAs were identified in all the samples and 83 DE lncRNAs were further screened, including 76 upregulated and 7 downregulated DE lncRNAs. GO and KEGG analyses predicted that the DE lncRNAs played notable roles in ‘protein/macromolecule glycosylation’, ‘regulation of protein ubiquitination’, ‘renin-angiotensin system’ and ‘MAPK signaling pathways’. A lncRNA-micro (mi)RNA-mRNA interaction network was constructed and used to perform association analyses. It was found that 83 lncRNAs were abnormally expressed in GHGIN, with some potential functions associated with gastric cancer. Furthermore, the lncRNA-miRNA-mRNA interaction network indicated that 7 DE lncRNAs may play a notable role in the occurrence and development of GHGIN. The results of the present study showed the expression profiles of lncRNAs in human GHGIN, elucidated some of the molecular changes associated with GHGIN and improved the understanding of the molecular mechanisms underlying GHGIN and gastric cancer.

Research updates on the clinical implication of long noncoding RNA in digestive system cancers and chemoresistance

Long noncoding RNAs (lncRNAs) are implicated in various biological processes, such as cell proliferation, differentiation, apoptosis, migration, and invasion. They are also key players in various biological pathways. LncRNA was considered as 'translational noise' before 1980s. It has been reported that lncRNAs are aberrantly expressed in different cancers, either as oncogene or tumor suppressor gene. Therefore, more and more lncRNAs are recognized as potential diagnostic biomarkers and/or therapeutic targets. As competitive endogenous RNA, lncRNAs can interact with microRNA to alter the expression of target genes, which may have extensive clinical implications in cancers, including diagnosis, treatment, prognosis, and chemoresistance. This review comprehensively summarizes the functions and clinical relevance of lncRNAs in digestive system cancers, especially as a potential tool to overcome chemoresistance.

LncRNA PCGEM1 induces proliferation and migration in non-small cell lung cancer cells through modulating the miR-590-3p/SOX11 axis

Background

Non-small cell lung cancer (NSCLC) is one of the most prevalent cancers. As reported, long non-coding RNAs (lncRNAs) induce various biological behaviors in cancers. LncRNA PCGEM1 prostate-specific transcript (PCGEM1) is reported to exert carcinogenic effect on certain cancers. Our research aimed to explore the role of PCGEM1 in NSCLC.

Methods

We enrolled forty NSCLC patients to explore PCGEM1 expression in clinical NSCLC tissues. Colony formation assay, CCK-8, Transwell assay were conducted to reveal cell proliferation, viability, migration and invasion. Luciferase reporter assay, RNA pull down, and RIP assay were performed to investigate the downstream axis of PCGEM1.

Results

PCGEM1 was significantly upregulated in NSCLC cells and tissues. Subsequently, in vitro loss-of-function experiments illustrated the carcinogenic role of PCGEM1 in NSCLC through promoting viability, proliferation, migration, and invasion. MiR-590-3p was confirmed to be a downstream gene of PCGEM1. Furthermore, SRY-box transcription factor 11 (SOX11) was verified to be a target of miR-590-3p. Additionally, rescue experiments indicated that miR-590-3p inhibitor or pcDNA3.1/SOX11 rescued the impacts of downregulated PCGEM1 on NSCLC cell proliferation, viability, migration and invasion.

Conclusions

LncRNA PCGEM1 aggravated proliferative and migrative abilities in NSCLC via the miR-590-3p/SOX11 axis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01600-9.

LncRNA UCA1 promotes development of gastric cancer via the miR-145/MYO6 axis

Background

Long noncoding RNA (lncRNA), urothelial carcinoma-associated 1 (UCA1) is aberrantly expressed in multiple cancers and has been verified as an oncogene. However, the underlying mechanism of UCA1 in the development of gastric cancer is not fully understood. In the present study, we aimed to identify how UCA1 promotes gastric cancer development.

Methods

The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) data were used to analyze UCA1 and myosin VI (MYO6) expression in gastric cancer. Western blot and quantitative real-time PCR (QPCR) were performed to test the expression level of the UCA1/miR-145/MYO6 axis in gastric cancer cell lines and tissues. The roles of the UCA1/miR-145/MYO6 axis in gastric cancer in vitro and in vivo were investigated by CCK-8 assay, flow cytometry, siRNAs, immunohistochemistry, and a mouse xenograft model. The targeted relationship among UCA1, miR-145, and MYO6 was predicted using LncBase Predicted v.2 and TargetScan online software, and then verified by luciferase activity assay and RNA immunoprecipitation.

Results

UCA1 expression was higher but miR-145 expression was lower in gastric cancer cell lines or tissues, compared to the adjacent normal cell line or normal tissues. Function analysis verified that UCA1 promoted cell proliferation and inhibited cell apoptosis in the gastric cancer cells in vitro and in vivo. Mechanistically, UCA1 could bind directly to miR-145, and MYO6 was found to be a downstream target gene of miR-145. miR-145 mimics or MYO6 siRNAs could partly reverse the effect of UCA1 on gastric cancer cells.

Conclusions

UCA1 accelerated cell proliferation and inhibited cell apoptosis through sponging miR-145 to upregulate MYO6 expression in gastric cancer, indicating that the UCA1/miR-145/MYO6 axis may serve as a potential therapeutic target for gastric cancer.

Roles of ncRNAs as ceRNAs in Gastric Cancer

Although ignored in the past, with the recent deepening of research, significant progress has been made in the field of non-coding RNAs (ncRNAs). Accumulating evidence has revealed that microRNA (miRNA) response elements regulate RNA. Long ncRNAs, circular RNAs, pseudogenes, miRNAs, and messenger RNAs (mRNAs) form a competitive endogenous RNA (ceRNA) network that plays an essential role in cancer and cardiovascular, neurodegenerative, and autoimmune diseases. Gastric cancer (GC) is one of the most common cancers, with a high degree of malignancy. Considerable progress has been made in understanding the molecular mechanism and treatment of GC, but GC’s mortality rate is still high. Studies have shown a complex ceRNA crosstalk mechanism in GC. lncRNAs, circRNAs, and pseudogenes can interact with miRNAs to affect mRNA transcription. The study of the involvement of ceRNA in GC could improve our understanding of GC and lead to the identification of potential effective therapeutic targets. The research strategy for ceRNA is mainly to screen the different miRNAs, lncRNAs, circRNAs, pseudogenes, and mRNAs in each sample through microarray or sequencing technology, predict the ceRNA regulatory network, and, finally, conduct functional research on ceRNA. In this review, we briefly discuss the proposal and development of the ceRNA hypothesis and the biological function and principle of ceRNAs in GC, and briefly introduce the role of ncRNAs in the GC’s ceRNA network.

Long Noncoding RNA UCA1 in Gastrointestinal Cancers: Molecular Regulatory Roles and Patterns, Mechanisms, and Interactions

The rising trend of gastrointestinal (GI) cancer has become a global burden due to its aggressive nature and poor prognosis. Long noncoding RNAs (lncRNAs) have recently been reported to be overexpressed in different GI cancers and may contribute to cancer progression and chemoresistance. They are featured with more than 200 nucleotides, commonly polyadenylated, and lacking an open reading frame. LncRNAs, particularly urothelial carcinoma-associated 1 (UCA1), are oncogenes involved in regulating cancer progression, such as cell proliferation, invasion, migration, and chemoresistance, particularly in GI cancer. This review was aimed to present an updated focus on the molecular regulatory roles and patterns of lncRNA UCA1 in progression and chemoresistance of different GI cancers, as well as deciphering the underlying mechanisms and its interactions with key molecules involved, together with a brief presentation on its diagnostic and prognostic values. The regulatory roles of lncRNA UCA1 are implicated in esophageal cancer, gastric cancer, pancreatic cancer, hepatobiliary cancer, and colorectal cancer, where they shared similar molecular mechanisms in regulating cancer phenotypes and chemoresistance. Comparatively, gastric cancer is the most intensively studied type in GI cancer. LncRNA UCA1 is implicated in biological roles of different GI cancers via interactions with various molecules, particularly microRNAs, and signaling pathways. In conclusion, lncRNA UCA1 is a potential molecular target for GI cancer, which may lead to the development of a novel chemotherapeutic agent. Hence, it also acts as a potential diagnostic and prognostic marker for GI cancer patients.

The Functional Role of Long Non-coding RNA UCA1 in Human Multiple Cancers: a Review Study

In various cancers, high-grade tumor and poor survival rate in patients with upregulated lncRNAs UCA1 have been confirmed. Urothelial carcinoma associated 1 (UCA1) is an oncogenic non-coding RNA with a length of more than 200 nucleotides. The UCA1 regulate critical biological processes that are involved in cancer progression, including cancer cell growth, invasion, migration, metastasis, and angiogenesis. So It should not surprise that UCA1 overexpresses in variety of cancers type, including pancreatic cancer, ovarian cancer, gastric cancer, colorectal cancer, breast cancer, prostate cancer, endometrial cancer, cervical cancer, bladder cancer, adrenal cancer, hypopharyngeal cancer, oral cancer, gallbladder cancer, nasopharyngeal cancer, laryngeal cancer, osteosarcoma, esophageal squamous cell carcinoma, renal cell carcinoma, cholangiocarcinoma, leukemia, glioma, thyroid cancer, medulloblastoma, hepatocellular carcinoma and multiple myeloma. In this article, we review the biological function and regulatory mechanism of UCA1 in several cancers and also, we will discuss the potential of its as cancer biomarker and cancer treatment.

The Effect of LncRNA Zinc Finger E-Box-Binding Homeobox 1 Antisense 1 on the Biological Characteristics of Gastric Cancer Cells by Regulating the MiR-200b/Wnt1 Axis

In recent decades, most gastric cancer patients are diagnosed in the advanced disease stage with poor prognosis, and more than half of the advanced-stage patients will relapse. This research explores lncRNA ZEB1-AS1’s effect on gastric cancer cell proliferation, invasion, apoptosis via regulating the miR-200b/Wnt1 molecular axis. ZEB1-AS1 and miR-200b expressions in BGC-803, SGC-7901, MKN-45, and AGS cells were measured by qRT-PCR. ZEB1-AS1 siRNA, miR-200b mimics, and miR-200b mimics + pcDNA3.1-ZEB1-AS1 were transfected into BGC-803 cells to study their respective effect on cell proliferation, invasion, apoptosis using CCK-8 and Transwell assays and flow cytometry, respectively. Dual-luciferase reporter gene assay is used to detect the luciferase activity of ZEB1-AS1 WT or MUT and Wnt1 WT or MUT after co-transfecting with miR-200b mimics. The expression of miR-200b in BGC-803 cells with knocked down or overexpressed ZEB1-AS1 was quantified with qRT-PCR. Western blot analysis was used to detect the protein level of Wnt1 in BGC-803 cells with upregulated or downregulated miR-200b expression. Data showed that ZEB1-AS1 expression was significantly raised when miR-200b expression was reduced (P < 0.05). BGC-803 cells were selected for follow-up experiments. ZEB1-AS1, Wnt1, and miR-200b were found to have a targeted regulatory relationship. The knockdown of ZEB1-AS1 and upregulation of miR-200b can hinder BGC-803 cell proliferation and invasion and expedite apoptosis. ZEB1-AS1 and miR-200b overexpression can reverse the effect of miR-200b upregulation on BGC-803 cell proliferation, invasion, and apoptosis. Therefore, lncRNA ZEB1-AS1 could impede gastric cancer cell proliferation and invasion and accelerate apoptosis via the regulation of the miR-200b/Wnt1 molecular axis.

Tumor-suppressive microRNA-551b-3p targets H6PD to inhibit gallbladder cancer progression

Gallbladder cancer (GBC) is a highly malignant cancer with poor prognosis. Extensive studies have reported the vital functionality of several microRNAs (miRNAs) in numerous human cancers, including GBC. Microarray analysis has identified the differentially expressed miR-551b-3p in GBC. Therefore, this study aims to validate the underlying mechanism by which miR-551b-3p participated in epithelial-mesenchymal transition (EMT), invasion and migration of GBCs. Bioinformatic analysis predicted the binding of miR-551b-3p to H6PD. We validated the reduced miR-551b-3p expression and increased H6PD expression in the GBC tissues and GBC cell lines. Artificial modulation of miR-551b-3p and H6PD (down- and upregulation) was conducted to explore their roles in EMT, invasive, and migratory abilities of GBCs, and the tumor-bearing mice were used to determine tumor growth. Overexpression of miR-551b-3p or silencing of H6PD was observed to suppress the expressions of N-cadherin and vimentin, and to promote the expression of E-cadherin, along with reduced invasive and migratory ability of GBCs. Mechanistically, miR-551b-3p could evidently target and inhibit the expression of H6PD. Moreover, in vivo experiments substantiated the tumor-inhibiting activities of miR-551b-3p in nude mice. Conjointly, our study suggests that overexpression of miR-551b-3p inhibited the EMT, migration, and invasion of GBCs by inhibiting the expression of H6PD, indicating that miR-551b-3p may serve as a potential target for future development of therapeutic strategies for GBC.

lncRNA ROR Promotes Gastric Cancer Drug Resistance

OBJECTIVE

Gastric cancer is one of the most common malignant tumors worldwide, and for resectable tumors, the most effective treatment is surgery with chemotherapy in neoadjuvant or adjuvant setting. However, the majority of patients fail to achieve the ideal initial response and/or develop resistance to chemotherapy. It was reported that long noncoding RNA regulator of reprogramming (ROR) is highly associated with the progression of gastric cancer. However, the role ROR in multidrug resistance (MDR) remains unclear.

METHODS

The messenger RNA levels of 63 specimens of patients with gastric cancer were determined by real-time polymerase chain reaction analysis and were correlated with drug resistance and survival of patients. To determine the cellular functions of ROR, we generated gastric cancer MDR cells. The effect of ROR depletion on multidrug resistance-associated protein 1 (MRP1) expression and cell apoptosis were examined by immunoblotting analyses, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and flow cytometry.

RESULTS

We found that ROR expression levels are positively associated with increased MDR and poor prognosis of patients with gastric cancer. Regulator of reprogramming expression is increased in gastric cancer cells resistant to adriamycin (ADR) and vincristine (VCR). Depletion of ROR reduced MRP1 expression and increased apoptosis of drug-resistant gastric cancer cells in response to ADR and VCR treatment.

CONCLUSIONS

We demonstrated that ROR expression promotes MRP1 expression and MDR of gastric cancer cells and is correlated with increased MDR and poor prognosis of patients with gastric cancer. Our finding highlighted the potential of targeting ROR to improve the efficacy of chemotherapy.

Long noncoding RNA PART1 restrains aggressive gastric cancer through the epigenetic silencing of PDGFB via the PLZF-mediated recruitment of EZH2

Current reports refer to the role of long noncoding RNA (lncRNA) prostate androgen-regulated transcript 1 (PART1) as a tumor suppressor in some types of cancer but as an oncogene in other kinds of cancer. In gastric cancer, it had been reported to be downregulated. However, the clinical significance and underlying mechanism of PART1 function in gastric cancer remains undefined. Here, seven differential expression levels of noncoding RNAs (DE-lncRNAs) were screened from gastric cancer through a probe reannotation of a human exon array. PART1 was selected for further study because of its high fold change number. In our cohort, PART1 was identified as a significant downregulated lncRNA in gastric cancer tissues by qPCR and in situ hybridization (ISH), and its low expression was significantly correlated with postoperative metastasis and short overall survival time after surgery. Through the results of gain-of-function experiments, PART1 was confirmed as a tumor suppressor that can decrease not only cell viability, migration, and invasion in vitro but also tumorigenesis and tumor metastasis in vivo. Mechanistically, RNA pull-down and RNA-binding protein immunoprecipitation (RIP) showed that PART1 interacts with androgen receptor (AR), and then, promyelocytic leukemia zinc finger (PLZF) is upregulated in an androgen-independent manner. In a chain reaction, chromatin immunoprecipitation (ChIP) assay additionally illustrated that PLZF upregulation increased the enrichment of EZH2 and H3K27 trimethylation in the platelet-derived growth factor (PDGFB) promotor, thereby inhibition of PDGFB and the subsequent PDGFRβ/PI3K/Akt signaling pathway. Based on these findings, we showed PART1 plays a tumor suppressor role by promoting PLZF expression followed by recruitment of EZH2 to mediate epigenetic PDGFB silencing and downstream PI3K/Akt inhibition, suggesting that PART1 has a key role in restraining the aggressive ability of GC cells and providing a novel perspective on lncRNAs in GC progression.

IGF2-AS knockdown inhibits glycolysis and accelerates apoptosis of gastric cancer cells through targeting miR-195/CREB1 axis

Dysregulation of long non-coding RNA (lncRNA) insulin growth factor 2 antisense (IGF2-AS) is being found to have relevance to tumorigenesis, including gastric cancer (GC). The purpose of this study was to further explore the detailed role and molecular mechanism of IGF2-AS in GC progression. The expression levels of IGF2-AS, miR-195 and cAMP responsive element binding protein 1 (CREB1) mRNA were assessed by qRT-PCR. Glucose consumption and lactate production were determined using a corresponding Commercial Assay Kit. Hexokinase 2 (HK2) and CREB1 protein levels were detected using western blot. Cell apoptosis was determined by flow cytometry. The targeted interaction between miR-195 and IGF2-AS or CREB1 was validated using dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Our data revealed that IGF2-AS was upregulated in GC tissues and predicted poor prognosis. IGF2-AS knockdown hampered glycolysis and accelerated apoptosis of GC cells. Moreover, IGF2-AS acted as a sponge of miR-195 and CREB1 was a direct target of miR-195. MiR-195 mediated the regulatory effect of IGF2-AS knockdown on GC cell glycolysis and apoptosis. MiR-195 exerted its regulatory effect on GC cell glycolysis and apoptosis by CREB1. Furthermore, IGF2-AS regulated CREB1 expression via sponging miR-195. In conclusion, our study suggested that IGF2-AS knockdown suppressed glycolysis and facilitated apoptosis in GC cells at least partly through sponging miR-195 and modulating CREB1 expression, highlighting a novel therapeutic strategy for GC treatment.

Circular RNA hsa_circ_0075828 promotes bladder cancer cell proliferation through activation of CREB1

Circular RNAs (circRNAs), one kind of non-coding RNA, have been reported as critical regulators for modulating gene expression in cancer. In this study, microarray analysis was used to screen circRNA expression profiles of bladder cancer (BC) 5637 cells, T24 cells and normal control SV-HUC-1 cells. The data from the microarray showed that hsa_circ_0075828 (named circCASC15) was most highly expressed in 5637 and T24 cells. circCASC15 was highly expressed in BC tissues and cells. Overexpression of circCASC15 was closely associated with BC tumor stage and promoted cell proliferation significantly in vitro and in vivo. Mechanistically, circCASC15 could act as miR-1224-5p sponge to activate the expression of CREB1 to promote cell proliferation in BC. In short, circCASC15 promotes cell proliferation in BC, which might be a new molecular target for BC diagnosis and therapy.

CREB1-induced miR-1204 promoted malignant phenotype of glioblastoma through targeting NR3C2

Background

Glioblastoma (GBM) is a subclass of brain malignancy with unsatisfactory prognosis. MicroRNAs (miRNAs) are a group of non-coding RNAs (ncRNAs) that exert key function on tumorigenesis and tumor development.

Purposes

The purpose of this work was to unravel the biological behavior and mechanism of miR-1204 in GBM.

Methods

Expressions of miR-1204, NR3C2 and CREB1 were detected by RT-qPCR and western blot. Proliferation and apoptosis of GBM cells were detected by CCK-8, colony formation, caspase-3 activity and TUNEL assays. Molecular interplays were examined by ChIP, RIP, and luciferase reporter assays.

Results

MiR-1204 level was elevated in GBM cell lines. Functionally, miR-1204 aggravated cell proliferation whereas suppressed cell apoptosis in GBM cells. Mechanistically, cAMP Responsive Element Binding Protein 1 (CREB1) bound to the promoter of miR-1204 and activated the transcription of miR-1204. Furthermore, miR-1204 targeted and inhibited Nuclear receptor subfamily 3 group C member 2 (NR3C2), a tumor suppressor gene in GBM cells. Rescue assays indicated that NR3C2 participated in the regulation of miR-1204 on the malignant phenotype of GBM cells.

Conclusions

We observed for the first time that CREB1-induced miR-1204 promoted malignant phenotype of GBM through targeting NR3C2, indicating that miR-1204 acted as a novel oncogenic miRNA in GBM.

The functions of N6-methyladenosine modification in lncRNAs

Increasing evidence indicates that mRNAs are often subject to posttranscriptional modifications. Among them, N6-methyladenosine (m6A), which has been shown to play key roles in RNA splicing, stability, nuclear export, and translation, is the most abundant modification of RNA. Extensive studies of m6A modification of mRNAs have been carried out, while little is known about m6A modification of long non-coding RNAs (lncRNAs). Recently, several studies reported m6A modification of lncRNAs. In this review, we focus on these m6A-modified lncRNAs and discuss possible functions of m6A modification.

Retrotransposons Manipulating Mammalian Skeletal Development in Chondrocytes

Retrotransposons are genetic elements that copy and paste themselves in the host genome through transcription, reverse-transcription, and integration processes. Along with their proliferation in the genome, retrotransposons inevitably modify host genes around the integration sites, and occasionally create novel genes. Even now, a number of retrotransposons are still actively editing our genomes. As such, their profound role in the evolution of mammalian genomes is obvious; thus, their contribution to mammalian skeletal evolution and development is also unquestionable. In mammals, most of the skeletal parts are formed and grown through a process entitled endochondral ossification, in which chondrocytes play central roles. In this review, current knowledge on the evolutional, physiological, and pathological roles of retrotransposons in mammalian chondrocyte differentiation and cartilage development is summarized. The possible biological impact of these mobile genetic elements in the future is also discussed.

Long Noncoding RNA ZFAS1 Promotes Progression of NSCLC via Regulating of miR-590-3p

The incidence and mortality rate of nonsmall cell lung cancer (NSCLC) are continuously increasing. Recently, the important roles of long noncoding ribonucleic acid (lncRNA) zinc finger antisense1 (ZFAS1) in the development of many disease have been proved. However, the roles of ZFAS1 in NSCLC are still not completely understood. Thus, this study aimed to explore the potential roles and underlying mechanisms of lncRNA ZFAS1 in the progression of NSCLC. Our results demonstrated that lncRNA ZFAS1 expression was significantly upregulated in NSCLC tissues and cell lines. Loss-of-function experiments revealed that lncRNA ZFAS1 inhibition could remarkably suppress NSCLC cells proliferation in vitro. Bioinformatic analysis and luciferase reporter assay revealed that lncRNA ZFAS1 directly interacted with miR-590-3p. Rescue experiments showed that miR-590-3p inhibitor reversed the cell proliferation function of lncRNA ZFAS1 knockdown in vitro. Furthermore, we confirmed that lncRNA ZFAS1 inhibited cell division cycle 42 (Cdc42) expression by regulating of miR-590-3p in NSCLC cells. Therefore, our study indicates that lncRNA ZFAS1/miR-590-3p axis is involved in NSCLC cell proliferation. It also suggests that lncRNA ZFAS1 is a putative tumor oncogene in NSCLC.

Long non-coding RNA signature in gastric cancer

Gastric cancer as a common human malignancy has been associated with aberrant expressions of several coding and non-coding genes. Long non-coding RNAs (lncRNAs) as regulators of gene expressions at different genomic, transcriptomic and post-transcriptomic levels are among putative biomarkers and therapeutic targets in gastric cancer. In the present study, we have searched available literature and listed lncRNAs that are involved in the pathogenesis of gastric cancer. In addition, we discuss associations between expressions of these lncRNAs and tumoral features or risk factors for gastric cancer. Based on the established role of lncRNAs in regulation of genomic stability, cell cycle, apoptosis, angiogenesis and other aspects of cell physiology, the potential of these transcripts as therapeutic targets in gastric cancer should be evaluated in future studies.

HOXC-AS1-MYC regulatory loop contributes to the growth and metastasis in gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most prevalent and deadly malignancies worldwide. Accumulating reports have indicated the participation of long non-coding RNAs (lncRNAs) in the onset and progression of GC.

METHODS

GSE109476 data was utilized to screen out lncRNAs dysregulated in GC. Gene expressions were determined by qRT-PCR and western blot. Both in vitro and in vivo experiments were carried out to assess the function of HOXC-AS1 in GC. The association between genes was verified via RIP, ChIP, CoIP, RNA pull down and luciferase reporter assays, as appropriate.

RESULTS

HOXC-AS1 was discovered to be upregulated in GC and located both in cytoplasm and in nucleus in GC cells. Functionally, inhibition of HOXC-AS1 restrained GC cell growth and metastasis both in vitro and in vivo. Moreover, HOXC-AS1 was proved to be trans-activated by c-MYC in GC. In return, HOXC-AS1 positively regulated MYC expression in GC through targeting miR-590-3p/MYC axis in cytoplasm and modulating BRG1/β-catenin complex-activated MYC transcription in nucleus. Furthermore, the rescue assays verified that MYC mediated HOXC-AS1-affected GC progression.

CONCLUSION

Our research illustrated a feedback loop of HOXC-AS1-MYC in aggravating GC cell growth and metastasis, highlighting HOXC-AS1 as a promising target for GC diagnosis and treatment.

LncRNAs as potential diagnostic and prognostic biomarkers in gastric cancer: A novel approach to personalized medicine

Gastric cancer is the third leading cause of cancer death with 5-year survival rate of about 30-35%. Since early detection is associated with decreased mortality, identification of novel biomarkers for early diagnosis and proper management of patients with the best response to therapy is urgently needed. Long noncoding RNAs (lncRNAs) due to their high specificity, easy accessibility in a noninvasive manner, as well as their aberrant expression under different pathological and physiological conditions, have received a great attention as potential diagnostic, prognostic, or predictive biomarkers. They may also serve as targets for treating gastric cancer. In this review, we highlighted the role of lncRNAs as tumor suppressors or oncogenes that make them potential biomarkers for the diagnosis and prognosis of gastric cancer. Relatively, lncRNAs such as H19, HOTAIR, UCA1, PVT1, tissue differentiation-inducing nonprotein coding, and LINC00152 could be potential diagnostic and prognostic markers in patients with gastric cancer. Also, the impact of lncRNAs such as ecCEBPA, MLK7-AS1, TUG1, HOXA11-AS, GAPLINC, LEIGC, multidrug resistance-related and upregulated lncRNA, PVT1 on gastric cancer epigenetic and drug resistance as well as their potential as therapeutic targets for personalized medicine was discussed.

UCA1 long non-coding RNA: An update on its roles in malignant behavior of cancers

The lncRNA urothelial carcinoma-associated 1 (UCA1) is a 1.4 kb long transcript which has been firstly recognized in human bladder cancer cell line. Subsequent studies revealed its over-expression in a wide array of human cancer cell lines and patients' samples. In addition to conferring malignant phenotype to cells, it enhances resistance to conventional anti-cancer drugs. Moreover, transcript levels of this lncRNA have been regarded as diagnostic markers in several cancer types including gastric, bladder and liver cancers. The underlying mechanism of its participation in carcinogenesis has been identified in some cancer types. Sponging tumor suppressor miRNAs, interacting with cancer-promoting signaling pathways and enhancing cell cycle progression are among these mechanisms. Although few studies have shown anti-carcinogenic properties for this lncRNA, the bulk of evidence supports its oncogenic roles. In the current study, we have reviewed the current literature on the role of UCA1 in the carcinogenic process based on the results of in vitro studies, investigations in animal models and assessment of UCA1 expression in clinical samples.

LncRNA UCA1 affects epithelial-mesenchymal transition, invasion, migration and apoptosis of nasopharyngeal carcinoma cells

Objective: In this study, long non-coding RNA urothelial carcinoma associated 1 (lncRNA UCA1) in nasopharyngeal carcinoma (NPC) and its effect on the malignant phenotype of NPC cells was investigated. Methods: Initially, the expression of UCA1 in NPC tissues and cells was detected. NPC cell line that with highest expression of UCA1 was selected for subsequent cell function test. A series of experiments were used to detect proliferation, colony formation, cell cycle distribution, apoptosis, invasion and migration of NPC cells with the interference of UCA1 expression. Western blot analysis was carried out to detect the expression of E-cadherin and vimentin for verifying the effect of UCA1 on epithelial mesenchymal transition (EMT). Results: The expression of UCA1 was found to be upregulated in NPC tissues and cells. The expression of UCA1 in stage Ⅲ + IV of NPC tissues and in patients with lymph node metastasis was significantly higher than that in patients at stage Ⅰ + Ⅱ and in patients without lymph node metastasis. Inhibition of UCA1 repressed proliferation, EMT, colony formation, invasion and migration while stimulating apoptosis of NPC cells. Conclusion: Our study suggests that UCA1 expression was overexpressed in NPC. Additionally, UCA1 suppression could inhibit proliferation, EMT, invasion and migration, and promote apoptosis of NPC cells.

The prognostic value and mechanisms of lncRNA UCA1 in human cancer

Long noncoding RNAs (lncRNAs), longer than 200 nucleotides in length, play important roles in the development and progression of various cancers. An increasing number of studies have revealed that lncRNAs function as potential oncogenes or tumor suppressors to influence biological processes, such as cell growth, invasion, migration and apoptosis. Urothelial carcinoma associated 1 (UCA1), an oncogenic lncRNA, was first found in bladder cancer and highly expressed in multiple cancers, including gastric cancer, colorectal cancer, lung cancer and breast cancer. UCA1 promotes tumorigenesis mainly via binding to tumor-suppressive microRNAs (miRNAs), activating several pivotal signaling pathways and alteration of epigenetic and transcriptional regulation. In addition, high expression of UCA1 is related to poor clinicopathological features especially for shorter overall survival, suggesting that UCA1 might be regarded as a prognosis biomarker in human cancers. In the present review, we summarized current studies on UCA1 to explore its prognostic value and underlying regulation mechanisms in the development of multiple cancers in order to provide a glimmer of hope for the prevention and treatment of malignant tumors.

Long Noncoding RNA FAM225A Promotes Nasopharyngeal Carcinoma Tumorigenesis and Metastasis by Acting as ceRNA to Sponge miR-590-3p/miR-1275 and Upregulate ITGB3

Long noncoding RNAs (lncRNA) play important roles in the tumorigenesis and progression of cancers. However, the clinical significance of lncRNAs and their regulatory mechanisms in nasopharyngeal carcinogenesis (NPC) are largely unknown. Here, based on a microarray analysis, we identified 384 dysregulated lncRNAs, of which, FAM225A was one of the most upregulated lncRNAs in NPC. FAM225A significantly associated with poor survival in NPC. N(6)-Methyladenosine (m6A) was highly enriched within FAM225A and enhanced its RNA stability. FAM225A functioned as an oncogenic lncRNA that promoted NPC cell proliferation, migration, invasion, tumor growth, and metastasis. Mechanistically, FAM225A functioned as a competing endogenous RNA (ceRNA) for sponging miR-590-3p and miR-1275, leading to the upregulation of their target integrin β3 (ITGB3), and the activation of FAK/PI3K/Akt signaling to promote NPC cell proliferation and invasion. In summary, our study reveals a potential ceRNA regulatory pathway in which FAM225A modulates ITGB3 expression by binding to miR-590-3p and miR-1275, ultimately promoting tumorigenesis and metastasis in NPC. SIGNIFICANCE: These findings demonstrate the clinical significance of the lncRNA FAM225A in nasopharyngeal carcinoma (NPC) and the regulatory mechanism involved in NPC development and progression, providing a novel prognostic indicator and promising therapeutic target.

Crosstalk between the lncRNA UCA1 and microRNAs in cancer

Long non-coding RNAs (lncRNAs) are a major subset of highly conserved non-coding RNAs (ncRNAs) that consist of at least 200 nucleotides and have limited protein-coding potential. Cumulative data have shown that lncRNAs are deregulated in many types of cancer and may control pathophysiological processes of cancer at various levels, including transcription, post-transcription and translation. Recently, lncRNAs have been demonstrated to interact with microRNAs (miRNAs), another major subset of ncRNAs, which regulate physiological and pathological processes by inhibiting target mRNA translation or promoting mRNA degradation. The lncRNA urothelial carcinoma-associated 1 (UCA1) has recently gained much attention as it is overexpressed in many types of cancer and is involved in carcinogenesis. Here, we review the crosstalk between UCA1 and miRNAs during the pathogenesis of cancer, with a focus on cancer-cell proliferation, invasion, drug resistance, and metabolism.

The Long Noncoding RNA UCA1 Negatively Regulates Melanogenesis in Melanocytes

The long noncoding RNA UCA1 was first discovered in bladder cancer and is known to regulate the proliferation and migration of melanoma. However, its role in melanogenesis is unclear. In this study, we aimed to explore the role and mechanism of UCA1 in melanogenesis. Our findings showed that the expression of UCA1 was negatively correlated with melanin content in melanocytes and pigmented nevus. Overexpression of UCA1 in melanocytes decreased melanin content and the expression of melanogenesis-related genes, whereas knockdown of UCA1 in melanocytes had the opposite effect. High-throughput sequencing revealed that microphthalmia-associated transcription factor (MITF), an important transcription factor affecting melanogenesis, was also negatively correlated with the expression of UCA1. Furthermore, the transcription factor CRE-binding protein (CREB), which promotes MITF expression, was negatively regulated by UCA1. The cAMP/protein kinase A (PKA), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) signaling pathways, which are upstream of the CREB/MITF/melanogenesis axis, were activated or inhibited in response to silencing or enhancing UCA1 expression, respectively. In addition, enhanced UCA1 expression downregulates the expression of melanogenesis-related genes induced by UVB in melanocytes. In conclusion, UCA1 may negatively regulate the CREB/MITF/melanogenesis axis through inhibiting the cAMP/PKA, ERK, and JNK signaling pathways in melanocytes. UCA1 may be a potential therapeutic target for the treatment of pigmented skin diseases.

The Association of HOTAIR with the Diagnosis and Prognosis of Gastric Cancer and Its Effect on the Proliferation of Gastric Cancer Cells

BACKGROUND

Long noncoding RNAs (lncRNAs) are a group of noncoding RNA with the length of more than 200nt. They have been identified as important diagnostic and prognostic molecules for many cancers and play an important role in the development of cancers. However, their clinical value and roles in gastric cancer (GC) remain unclear.

METHODS

The expression levels of HOTAIR in 54 GC tissues and their matched adjacent nontumor tissues from GC patients and 24 normal mucosa or those with minimal gastritis as healthy controls were determined by qRT-PCR. The expression levels of HOTAIR in human GC cell lines and a normal gastric epithelium cell line were also assessed by qRT-PCR. The potential relationships between its level in GC tissues and the clinicopathological features were analyzed. Furthermore, a receiver operating characteristic (ROC) curve was constructed. Additionally, the correlation between this lncRNA and overall survival (OS) was analyzed. SiRNA transfection was used to silence the expression of HOTAIR in GC cells. And cell proliferation and cell cycle assays were employed to determine the effect of HOTAIR on GC cell growth. Western blot was performed for the detection of the P53, P21, and Bcl2 proteins.

RESULTS

The expression levels of HOTAIR were significantly upregulated in GC tissues and cell lines. Increased HOTAIR was associated with tumor differentiation, lymph node and distant metastasis, and clinical stage. Furthermore, the area under the ROC curve (AUC) was up to 0.8416 (95 % CI=0.7661 to 0.9170, P<0.0001). The sensitivity and specificity were 66.67 and 87.04%, respectively. The correlation between HOTAIR expression and overall survival (OS) was statistically significant. The hazard ratio was 2.681, and 95% CI of ratio was 1.370 to 5.248. In addition, knockdown of HOTAIR can inhibit GC cell growth and affect cell cycle distribution. And knockdown of HOTAIR could enhance the protein levels of P21 and P53.

CONCLUSION

The present study demonstrated that HOTAIR was highly expressed in GC tissues and may serve as a potential diagnostic and prognostic biomarker for GC. And HOTAIR promoted GC cell proliferation.

The functional roles of exosomal long non-coding RNAs in cancer

Exosomes are extracellular membranous vesicles that are secreted by various cell types. Exosomes have become indispensable facilitators in the exchange of information between cells. More importantly, exosomes perform a crucial role in a variety of diseases including cancers. Long non-coding RNAs (lncRNAs) are over 200 nucleotides long transcripts that exhibit no or limited protein-coding potentials. LncRNAs are an emerging group of regulatory RNAs and can be selectively packaged into exosomes. Exosomal lncRNAs play a central role in carcinogenesis and cancer progression by modulating tumor growth, metastasis, angiogenesis and chemoresistance. Moreover, exosomal lncRNAs function as messengers in cell-to-cell communication, and thus remodel the tumor microenvironment. Their function relevance in cancer biology hints at the possibility of employing exosomal lncRNAs as promising, non-invasive biomarkers for further cancer therapy. In this review, we provide an overview of current research on the functional roles of exosomal lncRNAs in cancer and discuss their potential clinical applications as diagnostic biomarkers and therapeutic targets for cancers.

MicroRNA-590-3P suppresses cell survival and triggers breast cancer cell apoptosis via targeting sirtuin-1 and deacetylation of p53

Downregulation of microRNA-590-3p (miR-590-3p) is a frequently occurring, nonphysiological event which is observed in several human cancers, especially breast cancer. However, the significance of miR-590-3p still remain unclear in the progression of this disease. This study explored the role of miR-590-3p in apoptosis of breast cancer cells. Gene expression of miR-590-3p, Sirtuin-1 (SIRT1), Bcl-2 associated X protein (BAX), and p21 was evaluated with real-time polymerase chain reaction (PCR) and SIRT1 protein expression was assessed by Western blot analysis in breast cancer cell lines. Bioinformatics analysis and luciferase reporter assay were used to evaluate targeting of SIRT1 messenger RNA (mRNA) by miR-590-3p. Cells were transfected with miR-590-3p mimic and inhibitor and their effects on the expression and activity of SIRT1 were evaluated. The effects of miR-590-3p upregulation on the acetylation of p53 as well as cell viability and apoptosis were assessed by Western blot analysis, WST-1 assay, and flow cytometry, respectively. miR-590-3p expression was considerably downregulated in breast cancer cells which was accompanied by upregulation of SIRT1 expression. SIRT1 was recognized as a direct target for miR-590-3p in breast cancer cells and its protein expression and activity was dramatically inhibited by the miR-590-3p. In addition, there was an increase in p53 and its acetylated form that ultimately led to upregulation of BAX and p21 expression, suppression of cell survival, and considerable induction of apoptosis in breast cancer cells. These findings suggest that miR-590-3p exerts tumor-suppressing effects through targeting SIRT1 in breast cancer cells, which makes it a potential therapeutic target for developing more efficient treatments for breast cancer.

The UCA1/KRAS axis promotes human pancreatic ductal adenocarcinoma stem cell properties and tumor growth

Emerging evidence indicates that the long noncoding RNA UCA1 is upregulated in multiple cancers, including pancreatic ductal adenocarcinoma (PDAC), and plays a critical role in various complex biological processes. However, the functional roles of UCA1 in PDAC remain to be clarified. In the current study, we showed that UCA1 significantly promoted cell proliferation and tumor growth both in vitro and in vivo, and enhanced stemness maintenance of PDAC cell lines. Moreover, we found that UCA1 overexpression increased the activity and expression of oncogenic KRAS. Mechanistically, upregulated UCA1 increased phospho-KRAS protein levels by interacting with hnRNPA2B1, and KRAS facilitated high cytoplasmic accumulation of hnRNPA2B1. Additionally, we identified that UCA1 functioned as a competing endogenous RNA (ceRNA) to increase the expression of KRAS via sponging miR-590-3p, and in turn, KRAS promoted UCA1 expression. Collectively, these findings suggest that the UCA1-KRAS axis plays a crucial role in PDAC progression and that UCA1 may serve as a target for new PDAC therapies.

LONG-NONCODING RNAs in gastroesophageal cancers

Despite continuing improvements in multimodal therapies, gastro-esophageal malignances remain widely prevalent in the population and is characterized by poor overall and disease-free survival rates. Due to the lack of understanding about the pathogenesis and absence of reliable markers, gastro-esophageal cancers are associated with delayed diagnosis. The increasing understanding about cancer's molecular landscape in the recent years, offers the possibility of identifying 'targetable' molecular events and in particular facilitates novel treatment strategies and development of biomarkers for early stage diagnosis. At least 98% of our genome is actively transcribed into non-coding RNAs encompassing long non-coding RNAs (lncRNAs) constituted of transcripts longer than 200 nucleotides with no protein-coding capacity. Many studies have demonstrated that lncRNAs are functional genomic elements playing pivotal roles in main oncogenic processes. LncRNA can act at multiple levels developing a complex molecular network that can modulate directly or indirectly the expression of genes involved in tumorigenesis. In this review, we focus on lncRNAs as emerging players in gastro-esophageal carcinogenesis and critically assess their potential as reliable noninvasive biomarkers and in next generation targeted therapies.

Epigenetic Regulation by lncRNAs: An Overview Focused on UCA1 in Colorectal Cancer

Colorectal cancers have become the second leading cause of cancer-related deaths. In particular, acquired chemoresistance and metastatic lesions occurring in colorectal cancer are a major challenge for chemotherapy treatment. Accumulating evidence shows that long non-coding (lncRNAs) are involved in the initiation, progression, and metastasis of cancer. We here discuss the epigenetic mechanisms through which lncRNAs regulate gene expression in cancer cells. In the second part of this review, we focus on the role of lncRNA Urothelial Cancer Associated 1 (UCA1) to integrate research in different types of cancer in order to decipher its putative function and mechanism of regulation in colorectal cancer cells. UCA1 is highly expressed in cancer cells and mediates transcriptional regulation on an epigenetic level through the interaction with chromatin modifiers, by direct regulation via chromatin looping and/or by sponging the action of a diversity of miRNAs. Furthermore, we discuss the role of UCA1 in the regulation of cell cycle progression and its relation to chemoresistance in colorectal cancer cells.

Knockdown of lncRNA UCA1 inhibits proliferation and invasion of papillary thyroid carcinoma through regulating miR-204/IGFBP5 axis

Background

Long noncoding RNA (LncRNA) UCA1 has been reported to function as an oncogene in multiple cancers. However, the biological roles and underlying mechanism of UCA1 in papillary thyroid carcinoma (PTC) remain unclear. This study aimed to investigate the underlying function of UCA1 on thyroid cancer progression.

Materials and methods

A series of experiments involving Cell Counting Kit-8, wound-healing, and transwell invasion assays were conducted to determine the cellular capabilities of proliferation, migration, and invasion, respectively. Binding sites between UCA1 and miR-204 were identified using a luciferase reporter system, whereas mRNA and protein expression of target genes were determined by real-time quantitative reverse transcription-PCR (qRT-PCR) and Western blot, respectively.

Results

The results revealed that UCA1 was upregulated in PTC tissue and cell lines. UCA1 knockdown significantly suppressed the cell proliferation, migration, and invasion of TPC-1 cells. Bioinformatics analysis and luciferase reporter assay verified the complementary binding within UCA1 and miR-204 at the 3′-UTR. Moreover, miR-204 inhibition reversed the UCA1 knockdown-mediated inhibitory effect on cell proliferation, migration, and invasion. We also found that UCA1 could regulate expression of IGFBP5, a direct target of miR-204 in PTC.

Conclusion

Our study demonstrated that UCA1 exerts activity of oncogenes in PTC through regulating miR-204/IGFBP5 axis.

Emerging role of long non-coding RNA in the development of gastric cancer

Gastric cancer is a common, worldwide malignancy and has a poor prognosis due to late diagnosis. Long non-coding RNAs (lncRNAs) are a significant subtype of RNA molecules with a length longer than 200 nucleotides (nt) that rarely encode proteins. In recent decades, deregulation of lncRNAs has been shown to be involved in tumorigenesis and tumor progression in various human carcinomas, including gastric cancer. Accumulating evidence has shown that some lncRNAs may function as diagnostic biomarkers or therapeutic targets for gastric cancer. Thus, exploring the specific functions of lncRNAs will help both gain a better understanding of the pathogenesis and develop novel treatments for gastric cancer. In this review, we highlight the expression and functional roles of lncRNAs in gastric cancer, and analyze the potential applications of lncRNAs as diagnostic markers and therapeutic targets.

Prognostic value of long noncoding RNAs in gastric cancer: a meta-analysis

Background

In the last few years, accumulating evidence has indicated that numerous long noncoding RNAs (lncRNAs) are abnormally expressed in gastric cancer (GC) and are associated with the survival of GC patients. This study aimed to conduct a meta-analysis on 19 lncRNAs (AFAP1 antisense RNA 1 [AFAP1-AS1], CDKN2B antisense RNA 1 [ANRIL], cancer susceptibility 15 [CASC15], colon cancer associated transcript 2 [CCAT2], gastric adenocarcinoma associated, positive CD44 regulator, long intergenic noncoding RNA [GAPLINC], H19, imprinted maternally expressed transcript [H19], HOX transcript antisense RNA [HOTAIR], HOXA distal transcript antisense RNA [HOTTIP], long intergenic non-protein coding RNA 673 [LINC00673], metastasis-associated lung adenocarcinoma transcript 1 [MALAT1], maternally expressed 3 [MEG3], promoter of CDKN1A antisense DNA damage activated RNA [PANDAR], Pvt1 oncogene [PVT1], SOX2 overlapping transcript [Sox2ot], SPRY4 intronic transcript 1 [SPRY4-IT1], urothelial cancer associated 1 [UCA1], X inactive specific transcript [XIST], ZEB1 antisense RNA 1 [ZEB1-AS1] and ZNFX1 antisense RNA 1 [ZFAS1]) to systematically estimate their prognostic value in GC.

Methods

The qualified literature was systematically searched in PubMed, Web of Science, Embase and Cochrane Database of Systematic Reviews (up to March 16, 2018), and one meta-analysis relating to the relationship between lncRNA expression and overall survival (OS) of GC patients was performed. The only evaluation criterion of survival results was OS.

Results

A total of 6,095 GC patients and 19 lncRNAs from 51 articles were included in the present study. Among the listed 19 lncRNAs, 18 lncRNAs (other than SPRY4-IT1) showed a significantly prognostic value (P<0.05).

Conclusion

This meta-analysis suggested that the abnormally expressed lncRNAs (AFAP1-AS1, ANRIL, CASC15, CCAT2, GAPLINC, H19, HOTAIR, HOTTIP, LINC00673, MALAT1, MEG3, PANDAR, PVT1, Sox2ot, UCA1, XIST, ZEB1-AS1 and ZFAS1) were significantly associated with the survival of GC patients, among which AFAP1-AS1, CCAT2, LINC00673, PANDAR, PVT1, Sox2ot, ZEB1-AS1 and ZFAS1 were strong candidates in predicting the prognosis of GC patients.

CREB1, a direct target of miR-122, promotes cell proliferation and invasion in bladder cancer

Bladder cancer (BC) is a prevalent cancer, which arises from the epithelial lining of the urinary bladder. CAMP-response element binding protein (CREB1) acts as a transcription factor, which regulates cell transcription through phosphorylation and dephosphorylation. The purpose of this study was to explore how miR-122 worked in BC on cell proliferation and invasion. RT-qPCR was applied to evaluate the mRNA levels of CREB1 and miR-122 in BC. CCK-8 and Transwell assays were employed to determine the migratory and invasive abilities. Dual luciferase reporter assay was applied to verify miR-122 targeting CREB1 in BC. CREB1 was upregulated in bladder tissues and T24, UM-UC-3 and J82 cells, while miR-122 upregulated and had negative correlation with CREB1. Moreover, knockdown of CREB1 inhibited cell proliferative and invasive capacities. In addition, CREB1 was directly targeted by miR-122 in BC and regulated its expression. We discovered that CREB1 could reverse partially the function of miR-122 on cell proliferation and invasion. CREB1 was mediated by miR-122, and regulated cell proliferation and invasiveness. The newly identified miR-122/CREB1 axis provides novel insight into the pathogenesis of BC.

Emerging role of exosome-derived long non-coding RNAs in tumor microenvironment

Exosomes are extracellular vesicles released by many cell types and have been attributed for their roles in many diseases including cancer. Exosomes secreted by tumor cells and stromal cells are critical mediators of intercellular communication in tumor microenvironments. Long noncoding RNAs (lncRNAs) are selectively sorted into exosomes and can regulate cancer onset and progression in a variety of ways. In this review, we summarize the characteristics of exosomal lncRNAs and their dysregulation in multiple types of cancer. We provide an overview of current research on exosomal lncRNAs in tumor microenvironments, especially the functions of exosomal lncRNAs in regulating tumor biology. A deeper understanding of the role of exosomal lncRNAs in the tumor microenvironment may help provide new diagnostic and prognostic markers for cancer.