Long non-coding RNA LINC00978 promotes cell proliferation and tumorigenesis via regulating microRNA-497/NTRK3 axis in gastric cancer

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 MIR4435-2HG: a key molecule in progression of cancer and non-cancerous disorders

MIR4435-2HG (LINC00978) is a long non-coding RNA (lncRNA) that acts as an oncogene in almost all cancers. This lncRNA participates in the molecular cascades involved in other disorders such as coronary artery diseases, osteonecrosis, osteoarthritis, osteoporosis, and periodontitis. MIR4435-2HG exerts its functions via the spectrum of different mechanisms, including inhibition of apoptosis, sponging microRNAs (miRNAs), promoting cell proliferation, increasing cell invasion and migration, and enhancing epithelial to mesenchymal transition (EMT). MIR4435-2HG can regulate several signaling pathways, including Wnt, TGF-β/SMAD, Nrf2/HO-1, PI3K/AKT, MAPK/ERK, and FAK/AKT/β‑catenin signaling pathways; therefore, it can lead to tumor progression. In the present review, we aimed to discuss the potential roles of lncRNA MIR4435-2HG in developing cancerous and non-cancerous conditions. Due to its pivotal role in different disorders, this lncRNA can serve as a potential biomarker in future investigations. Moreover, it may serve as a potential therapeutic target for the treatment of various diseases.

MIR4435-2HG Is a Potential Pan-Cancer Biomarker for Diagnosis and Prognosis

The lncRNA MIR4435-2 host gene (MIR4435-2HG) is located on human chromosome 2q13, and its expression is up-regulated in 18 tumors. MIR4435-2HG participates in 6 signaling pathways to promote tumorigenesis, including the TGF-β signaling pathway, Wnt/β-catenin signaling pathway, MDM2/p53 signaling pathway, PI3K/AKT signaling pathway, Hippo signaling pathway, and MAPK/ERK signaling pathway. MIR4435-2HG competitively binds with 20 miRNAs to form a complex ceRNA network, thereby regulating the expression of downstream target genes. The high expression of MIR4435-2HG is also closely related to the clinicopathological characteristics and poor prognosis of a variety of tumors. Also, the high expression of MIR4435-2HG in peripheral blood or serum has the value of predicting the risk of 9 tumors. In addition, MIR4435-2HG participates in the mechanism of action of three cancer drugs, including resveratrol for the treatment of lung cancer, cisplatin for non-small cell lung cancer and colon cancer, and carboplatin for triple-negative breast cancer. This article systematically summarizes the diagnostic and prognostic value of MIR4435-2HG in a variety of tumors and outlines the ceRNA network and signaling pathways related to MIR4435-2HG, which will provide potential directions for future MIR4435-2HG research.

LncRNA00978 contributes to growth and metastasis of hepatocellular carcinoma cells via mediating microRNA-125b-5p/SOX12 pathway

As a malignant tumor, HCC (hepatocellular carcinoma) is featured by a high recurrence rate with a poor prognosis. Increasing evidence supports an important role of lincRNAs in HCC. Here, the purpose of the study was to explore the function of LINC00978 (long non-coding RNA00978) in HCC and the underlying mechanisms. LINC00978 expression and its association with the progression of HCC were analyzed using HCC TCGA datasets. LINC00978 expression in tissues was measured using real-time PCR. Then, we knocked down LINC00978 in HCC cells to explore its effect on cellular invasion, proliferation, and migration. Finally, we investigated the potential molecular mechanism of LINC00978 by dual Luciferase reporter assay, FISH (fluorescence in situ hybridization) and RIP (RNA immunoprecipitation). LINC00978 expression was remarkably increased in HCC. A high level of LINC00978 was associated with poor prognosis of HCC. Additionally, LINC00978 silencing could repress the growth and metastasis of HCC cells. Mechanistically, it was revealed that LINC00978 could sponge microRNA-125b-5p and identified SOX12 (SRY-Box Transcription Factor 12) as a direct target gene of microRNA-125b-5p. More importantly, the suppressed effect of LINC00978 silencing on the metastasis and growth of HCC cells could be rescued by miR-125b-5p inhibition and overexpressed SOX12. LINC00978/microRNA-125b-5p/SOX12 axis promoted liver cancer migration, invasion, and proliferation, which could be used as a possible therapeutic target for the treatment of hepatocellular carcinoma.

N6-methylandenosine-related lncRNAs play an important role in the prognosis and immune microenvironment of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive, fatal tumor. N6-methylandenosine (m6A) methylation is the major epigenetic modification of RNA including lncRNAs. The roles of m6A-related lncRNAs in PDAC have not been fully clarified. This study aims to assess gene signatures and prognostic value of m6A-related lncRNAs in PDAC. The Cancer Genome Atlas (TCGA) dataset and the International Cancer Genome Consortium (ICGC) dataset were explored to identify m6A-related lncRNAs. Univariate, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression were performed to construct the m6A-related lncRNAs prognostic riskscore (m6A-LPR) model to predict the overall survival (OS) in the TCGA training cohort. Kaplan–Meier curve with log-rank test and receiver operating characteristic (ROC) curve were used to evaluate the prognostic value of the m6A-LPR. Furthermore, the robustness of the m6A-LPR was further validated in the ICGC cohort. Tumor immunity was evaluated using ESTIMATE and CIBERSORT algorithms. A total of 262 m6A-related lncRNAs were identified in two datasets. In the TCGA training cohort, 28 prognostic m6A-related lncRNAs were identified and the m6A-LPR including four m6A-related lncRNAs was constructed. The m6A-LPR was able to identify high-risk patients with significantly poorer OS and accurately predict OS in both the TCGA training cohort and the ICGC validation cohort. Analysis of tumor immunity revealed that high-risk groups had remarkably lower stromal, immune, and ESTIMATE scores. Moreover, high-risk groups were associated with significantly higher levels of plasma B cells and resting NK cells infiltration, and lower levels of infiltrating resting memory CD4 T cells, monocytes, and resting mast cells. Our study proposed a robust m6A-related prognostic signature of lncRNAs for predicting OS in PDAC, which provides some clues for further studies focusing on the mechanism process underlying m6A modification of lncRNAs.

miR-497 defect contributes to gastric cancer tumorigenesis and progression via regulating CDC42/ITGB1/FAK/PXN/AKT signaling

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. MicroRNAs (miRNAs) are known to be important regulators of GC. This study aims to investigate the role of miRNA (miR)-497 in GC. We demonstrated that the expression of miR-497 was downregulated in human GC tissues. After N-methyl-N-nitrosourea treatment, the incidence of GC in miR-497 knockout mice was significantly higher than that in wild-type mice. miR-497 overexpression suppressed GC cell proliferation, cell-cycle progression, colony formation, anti-apoptosis ability, and cell migration and invasion capacity. Additionally, miR-497 overexpression decreased the expression levels of cell division cycle 42 (CDC42) and integrin β1 (ITGB1) and inhibited the phosphorylation of focal adhesion kinase (FAK), paxillin (PXN), and serine-threonine protein kinase (AKT). Furthermore, overexpression of miR-497 inhibited the metastasis of GC cells in vivo, which could be counteracted by CDC42 restoration. Furthermore, the focal adhesion of GC cells was found to be regulated by miR-497/CDC42 axis via ITGB1/FAK/PXN/AKT signaling. Collectively, it is concluded that miR-497 plays an important role in the repression of GC tumorigenesis and progression, partly via the CDC42/ITGB1/FAK/PXN/AKT pathway.

Knockdown of lncRNA MIR4435‑2HG and ST8SIA1 expression inhibits the proliferation, invasion and migration of prostate cancer cells in vitro and in vivo by blocking the activation of the FAK/AKT/β‑catenin signaling pathway

Prostate cancer is a main health risk for males with a high incidence and mortality. The present study aimed to examine the effects of long non‑coding RNA (lncRNA) MIR4435‑2HG binding with ST8SIA1 on the proliferation, invasion and migration of prostate cancer cells via the activation of the FAK/AKT/β‑catenin signaling pathway. The expression of MIR4435‑2HG and ST8SIA1 in prostate cancer cell lines, and the transfection efficacy were analyzed by RT‑qPCR. The proliferation, clone formation ability, and the invasion and migration of transfected cells were detected by CCK‑8 assay, clone formation assay, Transwell assay and wound healing assay, respectively. Plasmids were injected subcutaneously into mice to construct a xenograft tumor model. The expression levels of proteins related to proliferation, apoptosis, invasion and migration, and the FAK/AKT/β‑catenin pathway were detected by western blot analysis. The results revealed that MIR4435‑2HG expression was increased in the prostate cancer cell lines and MIR4435‑2HG expression was the highest in the PC‑3 cells. Interference with MIR4435‑2HG inhibited the proliferation, clone formation ability, and the invasion and migration of PC‑3 cells, as well as tumor growth by suppressing the activation of the FAK/AKT/β‑catenin signaling pathway. MIR4435‑2HG was demonstrated to target ST8SIA1. ST8SIA1 expression was also increased in the prostate cancer cell lines and MIR4435‑2HG expression was the highest in the PC‑3 cells. Interference with ST8SIA1 inhibited the promoting effects of MIR4435‑2HG on the proliferation, invasion and migration of PC‑3 cells, as well as tumor growth by suppressing the activation of the FAK/AKT/β‑catenin signaling pathway. On the whole, the present study demonstrates that interference with MIR4435‑2HG, combined with ST8SIA1, inhibits the proliferation, invasion and migration of prostate cancer cells in vitro and in vivo by blocking the activation of the FAK/AKT/β‑catenin signaling pathway.

LncRNA AWPPH as a prognostic predictor in human cancers in Chinese population: evidence from meta-analysis

Background: Long non-coding RNA associated with poor prognosis of hepatocellular carcinoma (AWPPH) is dysregulated in a variety of human cancers. However, the prognostic value of AWPPH in various cancers remains unclear.

Methods: Comprehensive literature search was performed in PubMed, Web of Science, CNKI and Wangfang databases, and eligible studies were obtained according to the inclusion and exclusion criteria. The pooled hazard ratios (HRs) and odds ratios (ORs) were applied to assess the clinical value of AWPPH expression for overall survival (OS) and clinicopathological features.

Results: A total of 19 articles including 1699 cancer patients were included in the study. The pooled results demonstrated that evaluated AWPPH expression was positively related to a poorer overall survival of patients with cancers (HR = 1.79, 95%CI: 1.44–2.14, P<0.001). Subgroup analysis revealed that tumor type and sample size affect the predictive value of AWPPH on OS, whereas cut-off value and HR estimation method have no impact on it. In addition, the pooled data also showed that AWPPH was positively linked to advanced TNM stage (OR = 2.50, 95%CI: 1.94–3.22, P<0.001), bigger tumor size (OR = 2.64, 95%CI: 1.47–4.73, P=0.001), macro-vascular invasion (OR = 2.08, 95%CI: 1.04–4.16, P=0.04) and lymph node metastasis (OR = 2.68, 95%CI: 1.82–3.96, P<0.001). Moreover, the results of the trim and fill analysis confirmed the reliability of our finding.

Conclusions: Up-regulation of AWPPH was associated with advanced TNM stage, bigger tumor size, worse lymph node metastasis, macro-vascular invasion and shorter overall survival, suggesting that AWPPH may serve as a biomarker for prognosis and clinicopathological characteristics in human cancers among the Chinese population.

Genome-wide analysis identifies critical DNA methylations within NTRKs genes in colorectal cancer

Background

Neurotrophic tropomyosin receptor kinases (NTRKs) are a gene family function as oncogene or tumor suppressor gene in distinct cancers. We aimed to investigate the methylation and expression profiles and prognostic value of NTRKs gene in colorectal cancer (CRC).

Methods

An analysis of DNA methylation and expression profiles in CRC patients was performed to explore the critical methylations within NTRKs genes. The methylation marker was validated in a retrospectively collected cohort of 229 CRC patients and tested in other tumor types from TCGA. DNA methylation status was determined by quantitative methylation-specific PCR (QMSP).

Results

The profiles in six CRC cohorts showed that NTRKs gene promoter was more frequently methylated in CRC compared to normal mucosa, which was associated with suppressed gene expression. We identified a specific methylated region within NTRK3 promoter targeted by cg27034819 and cg11525479 that best predicted survival outcome in CRC. NTRK3 promoter methylation showed independently predictive value for survival outcome in the validation cohort (P = 0.004, HR 2.688, 95% CI [1.355, 5.333]). Based on this, a nomogram predicting survival outcome was developed with a C-index of 0.705. Furthermore, the addition of NTRK3 promoter methylation improved the performance of currently-used prognostic model (AIC: 516.49 vs 513.91; LR: 39.06 vs 43.64, P = 0.032). Finally, NTRK3 promoter methylation also predicted survival in other tumors, including pancreatic cancer, glioblastoma and stomach adenocarcinoma.

Conclusions

This study highlights the essential value of NTRK3 methylation in prognostic evaluation and the potential to improve current prognostic models in CRC and other tumors.

Circular RNA hsa_circ_0009172 suppresses gastric cancer by regulation of microRNA-485-3p-mediated NTRK3

Gastric cancer is the third leading cause of cancer-related death worldwide, with relapse and metastasis being major contributors to the mortality. Circular RNAs (circRNAs) have been at the center of several researches and some circRNAs have been indicated to be involved in gastric cancer as sponges. Nevertheless, the mechanism underlying the function of circRNA remains largely unclear. Therefore, this study was conducted with the main objective of screening the associated circRNA in gastric cancer and exploring its mechanism. Expression of hsa_circRNA_0009172 was validated in gastric cancer tissues and cell lines after the correlation between hsa_circRNA_0009172 and prognosis was determined. Moreover, the binding site between miR-485-3p and hsa_circRNA_0009172 or NTRK3 was verified using dual luciferase assay and RNA pull down. Function-gain and -loss experiments were performed for the purpose of detecting the effect of hsa_circRNA_0009172 in vivo and in vitro as well as its mechanism with microRNA (miRNA)-485-3p and NTRK3 in gastric cancer. The hsa_circRNA_0009172 expression was downregulated in gastric cancer tissues and cell lines, indicating a positive association with patient prognosis. Functionally, hsa_circ_0009172 overexpression inhibited proliferative, invasive and migrative potential of gastric cancer cells as well as epithelial-mesenchymal transition (EMT)-related proteins by sponging miR-485-3p to inhibit NTRK3, while miR-485-3p overexpression could reverse the inhibitory effect of hsa_circ_0009172 on gastric cancer. Furthermore, either up-regulation of hsa_circ_0009172 or down-regulation of miR-485-3p led to the suppression of xenograft tumor growth in nude mice. In conclusion, hsa_circ_0009172 serves as a tumor suppressor in gastric cancer by targeting miR-485-3p/NTRK3 axis.

MiRNA-128-3p Restrains Malignant Melanoma Cell Malignancy by Targeting NTRK3

The functions of non-coding RNA, including microRNA (miRNA), have attracted considerable attention in the field of oncology, In this report, we examined the roles and molecular mechanisms of miR-128-3p, as related to the biological behaviors of malignant melanoma (MM). We found that miR-128-3p was expressed in low levels in these MM cells and may serve as a tumor suppressor by inhibiting proliferation, migration, and invasion, as well as inducing apoptosis in these MM cells. Moreover, neurotrophin receptor 3 (NTRK3), which serves as an oncogene that can enhance malignant behaviors of MM cells, was up-regulated in MM cells. Our current survey disclosed a complementary binding between miR-128-3p and the NTRK3 3' untranslated regions (3'-UTR), while luciferase activities of NTRK3 3'-UTR were restrained by miR-128-3p in 293T cells. The effects of pre-miR-128-3p and sh-NTRK3 as well as anti-miR-128-3p and NTRK3(+) appeared to function synergistically in producing malignant progression. Moreover, there were possible to have counteracted effects for pre-miR-128-3p and NTRK3(+) in malignant progression. These findings established that miR-128-3p can function as a tumor suppressor by inhibiting carcinogenesis of the oncogene, NTRK3. Collectively, miR-128-3p and NTRK3 genes participate in modulating the malignant behavior of MM, and may represent new therapeutic targets for MM.

Regulation of microRNA-497 expression in human cancer

MicroRNAs (miRNAs/miRs) are a type of non-coding single-stranded RNA, with a length of ~22 nt, which are encoded by endogenous genes and are involved in the post-transcriptional regulation of gene expression in animals and plants. Studies have demonstrated that miRNAs play an important role in the occurrence, development, metastasis, diagnosis and treatment of cancer. In recent years, miR-497 has been identified as one of the key miRNAs in a variety of cancer types and has been shown to be downregulated in a variety of solid tumors. However, the regulation of miR-497 expression involves a complex network, which is affected by several factors. The aim of the present review was to summarize the mechanism of regulation of miR-497 expression at the pre-transcriptional and transcriptional levels in cancer, as well as the role of miR-497 expression imbalance in cancer diagnosis, treatment and prognosis. The regulatory mechanisms of miR-497 expression may aid in our understanding of the causes of miR-497 expression imbalance and provide a reference value for further research on the diagnosis and treatment of cancer.

Fusobacterium nucleatum promotes epithelial-mesenchymal transiton through regulation of the lncRNA MIR4435-2HG/miR-296-5p/Akt2/SNAI1 signaling pathway

Fusobacterium nucleatum, an anaerobic oral opportunistic pathogen associated with periodontitis, has been considered to be associated with the development of oral squamous cell carcinoma (OSCC). However, the initial host molecular alterations induced by F. nucleatum infection which may promote predisposition to malignant transformation through epithelial–mesenchymal transition (EMT) have not yet been clarified. In the present study, we monitored the ability of F. nucleatum to induce EMT‐associated features, and our results showed that F. nucleatum infection promoted cell migration in either noncancerous human immortalized oral epithelial cells (HIOECs) or the two OSCC cell lines SCC‐9 and HSC‐4, but did not accelerate cell proliferation or cell cycle progression. Mesenchymal markers, including N‐cadherin, Vimentin, and SNAI1, were upregulated, while E‐cadherin was decreased and was observed to translocate to the cytoplasm. Furthermore, FadA adhesin and heat‐inactivated F. nucleatum were found to cause a similar effect as the viable bacterial cells. The upregulated lncRNA MIR4435‐2HG identified by the high‐throughput sequencing was demonstrated to negatively regulate the expression of miR‐296‐5p, which was downregulated in F. nucleatum‐infected HIOECs and SCC‐9 cells. The binding of MIR4435‐2HG and miR‐296‐5p was validated via a dual‐luciferase reporter assay. Additionally, knockdown of MIR4435‐2HG with siRNA leads to a decrease in SNAI1 expression, while miR‐296‐5p could further negatively and indirectly regulate SNAI1 expression via Akt2. Therefore, our study demonstrated that F. nucleatum infection could trigger EMT via lncRNA MIR4435‐2HG/miR‐296‐5p/Akt2/SNAI1 signaling pathway, and EMT process may be a probable link between F. nucleatum infection and initiation of oral epithelial carcinomas.

Roles of TrkC Signaling in the Regulation of Tumorigenicity and Metastasis of Cancer

Tropomyosin receptor kinase (Trk) C contributes to the clinicopathology of a variety of human cancers, and new chimeric oncoproteins containing the tyrosine kinase domain of TrkC occur after fusion to the partner genes. Overexpression of TrkC and TrkC fusion proteins was observed in patients with a variety of cancers, including mesenchymal, hematopoietic, and those of epithelial cell lineage. Both microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) were involved in the regulation of TrkC expression through transcriptional and posttranscriptional alteration. Aberrant activation of TrkC and TrkC fusion proteins markedly induces the epithelial-mesenchymal transition (EMT) program, growth rate, tumorigenic capacity via constitutive activation of Ras-MAP kinase (MAPK), PI3K-AKT, and the JAK2-STAT3 pathway. The clinical trial of TrkC or TrkC fusion-positive cancers with newly developed Trk inhibitors demonstrated that Trk inhibitors were highly effective in inducing tumor regression in patients who do not harbor mutations in the kinase domain. Recently, there has been a progressive accumulation of mutations in TrkC or the TrkC fusion protein detected in the clinic and its related cancer cell lines caused by high-throughput DNA sequencing. Despite given the high overall response rate against Trk or Trk fusion proteins-positive solid tumors, acquired drug resistance was observed in patients with various cancers caused by mutations in the Trk kinase domain. To overcome acquired resistance caused by kinase domain mutation, next-generation Trk inhibitors have been developed, and these inhibitors are currently under investigation in clinical trials.

Characterization of long non-coding RNA and messenger RNA profiles in laryngeal cancer by weighted gene co-expression network analysis

Laryngeal cancer (LC) is a malignant tumor in the head and neck region. It was recently elucidated that long non-coding RNAs (lncRNAs) participate in the pathogenesis of LC. However, the detailed mechanism of lncRNA in LC and whether long non-coding RNAs serve as effective biomarkers remains unclear. Ribonucleic acid (RNA) sequence data of LC and 11 patient clinical traits were extracted from The Cancer Genome Atlas (TCGA) database and analyzed by weighted gene co-expression network analysis (WGCNA). A total of 9 co-expression modules were identified. The co-expression Pink module significantly correlated with four clinical traits, including history of smoking, lymph node count, tumor status, and the success of follow-up treatment. Based on the co-expression Pink module, lncRNA-microRNA (miRNA)-messenger RNA (mRNA) and lncRNA-RNA binding protein-mRNA networks were constructed. We found that 8 lncRNAs significantly impacted overall survival (OS) in LC patients. These identified lncRNA and hub gene biomarkers were also validated in multiple LC cells in vitro via qPCR. Taken together, this study provided the framework of co-expression gene modules of LC and identified some important biomarkers in LC development and disease progression.

LINC00978 promotes the progression of hepatocellular carcinoma by regulating EZH2-mediated silencing of p21 and E-cadherin expression

Long non-coding RNAs (lncRNAs) have been suggested as important regulators of cancer development and progression in hepatocellular carcinoma (HCC). Nevertheless, the clinical value and biological roles of LINC00978 in HCC remain unclear. In this study, we detected the expression of LINC00978 in tumor tissues and serum of HCC patients, examined the roles of LINC00978 in HCC progression and elucidated the underlying molecular mechanisms. We found that LINC00978 expression was upregulated in tumor tissues and serum of HCC patients. Higher serum levels of LINC00978 could distinguish HCC patients from hepatitis and liver cirrhosis patients and healthy controls. LINC00978 knockdown inhibited HCC cell proliferation, migration and invasion while promoted cell cycle arrest and apoptosis. Overexpression of LINC00978 led to the opposite effects. LINC00978 knockdown also inhibited HCC growth and metastasis in mouse tumor models. Mechanistically, LINC00978 bound to EZH2 and mediated its accumulation at the promoter region of p21 and E-cadherin genes, leading to the trimethylation of H27K3 and the inhibition of p21 and E-cadherin expression. Moreover, the simultaneous depletion of p21 and E-cadherin expression reversed the inhibitory effects of LINC00978 knockdown on HCC cell proliferation, migration, and invasion. Taken together, these findings suggest that LINC00978 promotes HCC progression by inhibiting p21 and E-cadherin expression via EZH2-mediated epigenetic silencing. LINC00978 may represent a novel biomarker for HCC diagnosis, prognosis, and therapy.