lncAKHE enhances cell growth and migration in hepatocellular carcinoma via activation of NOTCH2 signaling

Unveiling the role of GAS41 in cancer progression

GAS41, a member of the human YEATS domain family, plays a pivotal role in human cancer development. It serves as a highly promising epigenetic reader, facilitating precise regulation of cell growth and development by recognizing essential histone modifications, including histone acetylation, benzoylation, succinylation, and crotonylation. Functional readouts of these histone modifications often coincide with cancer progression. In addition, GAS41 functions as a novel oncogene, participating in numerous signaling pathways. Here, we summarize the epigenetic functions of GAS41 and its role in the carcinoma progression. Moving forward, elucidating the downstream target oncogenes regulated by GAS41 and the developing small molecule inhibitors based on the distinctive YEATS recognition properties will be pivotal in advancing this research field.

A Positive Feedback Loop of lncRNA HOXD-AS2 and SMYD3 Facilitates Hepatocellular Carcinoma Progression via the MEK/ERK Pathway

Purpose

HOX cluster-embedded long noncoding RNAs (HOX-lncRNAs) have been shown to be tightly related to hepatocellular carcinoma (HCC). However, the potential biological roles and underlying molecular mechanism of HOX-lncRNAs in HCC largely remains to be elucidated.

Methods

The expression signature of eighteen HOX-lncRNAs in HCC cell lines were measured by qRT-PCR. HOXD-AS2 expression and its clinical significance in HCC was investigated by bioinformatics analysis utilizing the TCGA data. Subcellular localization of HOXD-AS2 in HCC cells was observed by RNA-FISH. Loss‑of‑function experiments in vitro and in vivo were conducted to probe the roles of HOXD-AS2 in HCC. Potential HOXD-AS2-controlled genes and signaling pathways were revealed by RNA-seq. Rescue experiments were performed to validate that SMYD3 mediates HOXD-AS2 promoting HCC progression. The positive feedback loop of HOXD-AS2 and SMYD3 was identified by luciferase reporter assay and ChIP-qPCR.

Results

HOXD-AS2 was dramatically elevated in HCC, and its up-regulation exhibited a positive association with aggressive clinical features (T stage, pathologic stage, histologic grade, AFP level, and vascular invasion) and unfavorable prognosis of HCC patients. HOXD-AS2 was distributed both in the nucleus and the cytoplasm of HCC cells. Knockdown of HOXD-AS2 restrained the proliferation, migration, invasion of HCC cells in vitro, as well as tumor growth in subcutaneous mouse model. Transcriptome analysis demonstrated that SMYD3 expression and activity of MEK/ERK pathway were impaired by silencing HOXD-AS2 in HCC cells. Rescue experiments revealed that SMYD3 as downstream target mediated oncogenic functions of HOXD-AS2 in HCC cells through altering the expression of cyclin B1, cyclin E1, MMP2 as well as the activity of MEK/ERK pathway. Additionally, HOXD-AS2 was uncovered to be positively regulated at transcriptional level by its downstream gene of SMYD3.

Conclusion

HOXD-AS2, a novel oncogenic HOX-lncRNA, facilitates HCC progression by forming a positive feedback loop with SMYD3 and activating the MEK/ERK pathway.

Mechanistic insights into genomic structure and functions of a novel oncogene YEATS4

As a novel oncogene, the role of YEATS domain-containing protein 4 (YEATS4) in the occurrence, development, and treatment of tumors is now beginning to be appreciated. YEATS4 plays an important role in regulating DNA repair during replication. The upregulation of YEAST4 promotes DNA damage repair and prevents cell death, whereas its downregulation inhibits DNA replication and induces apoptosis. Additionally, accumulating evidence indicates that the aberrant activation of YEATS4 leads to changes in drug resistance, epithelial-mesenchymal transition and also in the migration and invasion capacity of tumor cells. Therefore, specific inhibition of the expression or activity of YEATS4 protein may be an effective strategy for inhibiting the proliferation, motility, differentiation, and/or survival of tumor cells. Taken together, YEATS4 has emerged as a potential target for multiple cancers and is an attractive protein for the development of small-molecule inhibitors. However, research on YEAST4 in tumor-related fields is limited and its biological functions, metabolism, and the regulatory mechanism of YEATS4 in numerous cancers remain undetermined. This review comprehensively and extensively summarizes the functions, structure and oncogenic roles of YEATS4 in cancer progression and aims to further contribute to the study of its underlying molecular mechanism and targeted drugs.

The cancer-testis lncRNA LINC01977 promotes HCC progression by interacting with RBM39 to prevent Notch2 ubiquitination

Cancer-testis genes are involved in the occurrence and development of cancer, but the role of cancer-testis-associated lncRNAs (CT-lncRNAs) in hepatocellular carcinoma (HCC) remains to be explored. Here, we discovered a novel CT-lncRNA, LINC01977, based on the Genotype-Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) databases. LINC01977 was exclusively expressed in testes and highly expressed in HCC. High LINC01977 levels correlated with poorer overall survival (OS) in individuals with HCC. Functional assays showed that LINC01977 promoted HCC growth and metastasis in vitro and in vivo. Mechanistically, LINC01977 directly bound to RBM39 to promote the further entry of Notch2 into the nucleus, thereby preventing the ubiquitination and degradation of Notch2. Furthermore, the RNA binding protein IGF2BP2, one of the m⁶A modification readers, enhanced the stability of LINC01977, resulting in its high level in HCC. Therefore, the data suggest that LINC01977 interacts with RBM39 and promotes the progression of HCC by inhibiting Notch2 ubiquitination and degradation, indicating that LINC01977 may be a potential biomarker and therapeutic target for HCC patients.

Mutual Regulation of ncRNAs and Chromatin Remodeling Complexes in Normal and Pathological Conditions

Chromatin remodeling is the one of the main epigenetic mechanisms of gene expression regulation both in normal cells and in pathological conditions. In recent years, a growing number of investigations have confirmed that epigenetic regulators are tightly connected and form a comprehensive network of regulatory pathways and feedback loops. Genes encoding protein subunits of chromatin remodeling complexes are often mutated and change their expression in diseases, as well as non-coding RNAs (ncRNAs). Moreover, different mechanisms of their mutual regulation have already been described. Further understanding of these processes may help apply their clinical potential for establishment of the diagnosis, prognosis, and treatment of the diseases. The therapeutic targeting of the chromatin structure has many limitations because of the complexity of its regulation, with the involvement of a large number of genes, proteins, non-coding transcripts, and other intermediary molecules. However, several successful strategies have been proposed to target subunits of chromatin remodeling complexes and genes encoding them, as well as the ncRNAs that regulate the operation of these complexes and direct them to the target gene regions. In our review, we focus on chromatin remodeling complexes and ncRNAs, their mutual regulation, role in cellular processes and potential clinical application.

The Role and Mechanism of Autophagy in Pancreatic Cancer: An Update Review

Pancreatic cancer, with high morbidity and mortality rates, is one of the most malignant tumors worldwide. Despite extensive research, the prognosis remains poor. Autophagy, a lysosomal-mediated, highly conserved degradation process that removes abnormal proteins and damaged organelles from the body, is upregulated in pancreatic ductal adenocarcinoma. Based on differences in the tumor microenvironment and tumor stage, the functions of autophagy in the pathophysiology and treatment of pancreatic cancer differ. In the initial phase, autophagy inhibits the transformation of precancerous lesions to cancer. However, in the progressive stage, autophagy promotes tumor growth. Autophagy is also one of the main mechanisms of drug resistance during treatment. Here, we describe the role of autophagy in pancreatic cancer progression and discuss relevant treatment strategies for this disease.

The Impact of Long Non-Coding RNAs in the Pathogenesis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is among the utmost deadly human malignancies. This type of cancer has been associated with several environmental, viral, and lifestyle risk factors. Among the epigenetic factors which contribute in the pathogenesis of HCC is dysregulation of long non-coding RNAs (lncRNAs). These transcripts modulate expression of several tumor suppressor genes and oncogenes and alter the activity of cancer-related signaling axes. Several lncRNAs such as NEAT1, MALAT1, ANRIL, and SNHG1 have been up-regulated in HCC samples. On the other hand, a number of so-called tumor suppressor lncRNAs namely CASS2 and MEG3 are down-regulated in HCC. The interaction between lncRNAs and miRNAs regulate expression of a number of mRNA coding genes which are involved in the pathogenesis of HCC. H19/miR-15b/CDC42, H19/miR-326/TWIST1, NEAT1/miR-485/STAT3, MALAT1/miR-124-3p/Slug, MALAT1/miR-195/EGFR, MALAT1/miR-22/SNAI1, and ANRIL/miR-144/PBX3 axes are among functional axes in the pathobiology of HCC. Some genetic polymorphisms within non-coding regions of the genome have been associated with risk of HCC in certain populations. In the current paper, we describe the recent finding about the impact of lncRNAs in HCC.

Decoding the Roles of Long Noncoding RNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies worldwide. HCC is associated with several etiological factors, including HBV/HCV infections, cirrhosis, and fatty liver diseases. However, the molecular mechanism underlying HCC development remains largely elusive. The advent of high-throughput sequencing has unveiled an unprecedented discovery of a plethora of long noncoding RNAs (lncRNAs). Despite the lack of coding capacity, lncRNAs have key roles in gene regulation through interacting with various biomolecules. It is increasingly evident that the dysregulation of lncRNAs is inextricably linked to HCC cancer phenotypes, suggesting that lncRNAs are potential prognostic markers and therapeutic targets. In light of the emerging research in the study of the regulatory roles of lncRNAs in HCC, we discuss the association of lncRNAs with HCC. We link the biological processes influenced by lncRNAs to cancer hallmarks in HCC and describe the associated functional mechanisms. This review sheds light on future research directions, including the potential therapeutic applications of lncRNAs.

Long non-coding RNAs: the tentacles of chromatin remodeler complexes

Chromatin remodeler complexes regulate gene transcription, DNA replication and DNA repair by changing both nucleosome position and post-translational modifications. The chromatin remodeler complexes are categorized into four families: the SWI/SNF, INO80/SWR1, ISWI and CHD family. In this review, we describe the subunits of these chromatin remodeler complexes, in particular, the recently identified members of the ISWI family and novelties of the CHD family. Long non-coding (lnc) RNAs regulate gene expression through different epigenetic mechanisms, including interaction with chromatin remodelers. For example, interaction of lncBRM with BRM inhibits the SWI/SNF complex associated with a differentiated phenotype and favors assembly of a stem cell-related SWI/SNF complex. Today, over 50 lncRNAs have been shown to affect chromatin remodeler complexes and we here discuss the mechanisms involved.

YEATS4 is associated with poor prognosis and promotes epithelial-to-mesenchymal transition and metastasis by regulating ZEB1 expression in breast cancer

YEATS domain-containing protein 4 (YEATS4) is implicated in several oncogenic signaling pathways, and its expression is involved in various types of cancer; regardless, the pathophysiologic effects of YEATS4 on breast cancer remain unclear. This study finds that YEATS4 is increasingly expressed with breast cancer progression, and its expression is related to poor outcome and distant metastasis. YEATS4 overexpression in breast cancer cells strengthens their malignant characteristics in vitro and in vivo, particularly inducing epithelial-to-mesenchymal transition (EMT) and consequently, metastatic capability in breast cancer cells. By contrast, deleting YEATS4 in breast cancer cells with high-grade malignancy reduced these characteristics. With regard to the molecular mechanism, YEATS4 mediates histone H3K27ac at specific sites of the ZEB1 promoter to regulate its expression at the transcription level. Depleting ZEB1 blocks YEATS4-induced EMT, migration, invasion, and metastasis. YEATS4 expression is also positively correlated with ZEB1 expression in patients with breast cancer. Co-expression of YEATS4 and ZEB1 correlates with the shortest distant metastasis-free period. Taken together, our data reveal the critical role of YEATS4 in the progression and metastasis of breast cancer, as well as support YEATS4 as a potential therapeutic target and prognostic biomarker for breast cancer.

High expression of Notch2 drives tongue squamous cell carcinoma carcinogenesis

Tongue squamous cell carcinoma (TSCC) is one of the most common cancers in the oral cavity. Notch signaling is frequently dysregulated in cancer. However, the role of Notch2 in TSCC is not well understood. The aim of this study was to investigate the effect of abnormal expression of Notch2 in TSCC. The expression of Notch2 was tested in 47 pairs of tissues from tongue cancer and normal samples by using immunohistochemical staining. Tongue cancer cells were transfected with siRNA or plasmid. The proliferation of the cells was tested by the CCK8 assay and colony formation assay. Subcutaneous tumor model was established to observe tumor growth. Transwell assay was used to detect the changes of cell migration and invasion ability. A humanized anti-Notch2 antibody was used to TSCC cells. We found that Notch2 was upregulated in tongue carcinoma tissues. Knocking down the expression of Notch2 by siRNA in the TSCC cell lines decreased proliferation ability both in vitro and in vivo. In addition, migration and invasion abilities were inhibited by knockdown of Notch2 in the TSCC cells. However, overexpression of Notch2 increased tongue cancer cell proliferation, invasion and migration. The humanized anti-Notch2 antibody inhibited TSCC cell growth. The results indicated that Notch2 is an oncogene in tongue squamous cell carcinoma and may become the target of a new approach for treating TSCC.

Long non-coding RNA AGAP2-AS1 increases the invasiveness of papillary thyroid cancer

Papillary thyroid cancer (PTC) is considered a low hazard endocrine system cancer, but a considerable number of patients have poor prognosis because of lymph node metastasis and invasion of surrounding tissues. In this study, we analyzed the expression and function of the long non-coding RNA (lncRNA) AGAP2-AS1 in PTC. We found that AGAP2-AS1 expression was significantly higher in human PTC tissues than adjacent noncancerous tissues (n=110; p<0.01) and correlated with lymph node metastasis (p=0.01) and tumor-node-metastasis stage (p=0.006). AGAP2-AS1 downregulation decreased migration and invasion by PTC cells, and reduced expression of matrix metalloproteinase-2 (MMP2). AGAP2-AS1 upregulated MMP2 expression by competitively binding to microRNA-425-5p. In addition, miR-424-5p expression was decreased in PTC tissues and correlates negatively with the AGAP2-AS1 levels. These results demonstrate that AGAP2-AS1 expression is significantly elevated in PTC tissues and that, by binding to miRNA-425-5p, it upregulates the MMP2 expression, thereby increasing the invasiveness and migration capacity of PTC cells.

LncRNA ANCR Suppresses the Progression of Hepatocellular Carcinoma Through the Inhibition of Wnt/β-Catenin Signaling Pathway

Objective

Our study aimed to investigate the effect of anti-differentiation noncoding RNA (ANCR) on hepatocellular carcinoma (HCC) and its potential molecular mechanisms.

Methods

The expression of ANCR was detected by qRT-RCR in both HCC tissues and HCC cells. Moreover, the relationship between ANCR expression and clinical parameters in HCC patients was investigated. The proliferation, cell clones, migration, invasion and apoptosis of MHCC97H and HCCLM3 cells were measured by MTT assay, colony formation assay, transwell assay and flow cytometry, respectively. The expressions of N-cadherin, vimentin, E-cadherin, cleaved caspase-3, Bax, Bcl-2, Wnt1, β-catenin and GSK-3β in MHCC97H and HCCLM3 cells were measured by Western blot.

Results

Our results showed that ANCR was lowly expressed in both HCC tissues and HCC cells. ANCR expression was closely associated with tumor size, tumor-node-metastasis (TNM) stages and vascular invasion in HCC. ANCR could dramatically inhibit cell proliferation, migration and invasion, as well as promote apoptosis in MHCC97H and HCCLM3 cells. ANCR could significantly increase the expression of cleaved caspase-3, Bax, E-cadherin and GSK-3β but reduce the expression of Bcl-2, N-cadherin, vimentin, Wnt1 and β-catenin in MHCC97H and HCCLM3 cells. In addition, Wnt/β-catenin pathway inhibitor (IWP-2) partially reversed the effects of silencing ANCR on the proliferation, migration, invasion and apoptosis of HCCLM3 cells.

Conclusion

Our study demonstrated that ANCR can suppress cell proliferation, migration and invasion, as well as promote apoptosis of HCC cells via modulation of the Wnt/β-catenin signaling pathway.

Screening and verification of long noncoding RNA promoter methylation sites in hepatocellular carcinoma

Background

Long noncoding ribonucleic acid (lncRNA) promoter methylation is closely related to the occurrence and development of hepatocellular carcinoma (HCC). Thus, we aim to screen and verify the lncRNA promoter methylation sites associated with overall survival (OS), vascular invasion, pathological grade, and clinical stage in HCC.

Methods

Methylation-related data including clinical characteristic, transcriptome, methylation, and messenger RNA (mRNA) expression were taken from the Cancer Genome Atlas (TCGA) database. The OS, vascular invasion, pathological grade, and clinical stage-related lncRNA promoter methylation models were developed by the least absolute shrinkage and selection operator (LASSO) algorithm based on the lncRNA promoter methylation sites screened via R software. The Kaplan-Meier analysis, the area under the receiver operating characteristic (ROC) curve (AUC), the calibration curve (C-index) were performed to evaluate the performance of these models. Finally, the methylation-specific polymerase chain reaction (MS-PCR) was performed to verify the accuracy of these models based on 146 HCC tissues from our hospital.

Results

A total of 10 methylation sites were included in the OS-related lncRNA promoter methylation model that could effectively divide HCC patients into high-risk and low-risk groups (P < 0.0001) via survival analysis. COX univariable and multivariable regression analysis found that the OS-related model (P < 0.001, 95% CI 1.378-2.942) and T stage (P < 0.001, 95% CI 1.490-3.418) were independent risk factors affecting OS in HCC patients. The vascular invasion-related model contained 8 methylation sites with its AUC value of 0.657; the pathological grade-related model contained 22 methylation sites with its AUC value of 0.797; the clinical stage-related model contained 13 methylation sites with its AUC of 0.724. Target genes corresponded to vascular invasion-related lncRNA promoter methylation sites were involved in many kinds of biological processes in HCC such as PI3K-Akt signaling pathway. The accuracy of the vascular invasion-related model was consistent with our bioinformatics conclusion after being verified via MS-PCR.

Conclusion

The lncRNA promoter methylation sites are closely correlated with the process of HCC and can be utilized to improve the therapy and prognosis of HCC.

Galangin promotes cell apoptosis through suppression of H19 expression in hepatocellular carcinoma cells

Background

Galangin has been extensively studied as the antitumor agent in various cancers. However, the effect of galangin in hepatocellular carcinoma (HCC) remains elusive.

Methods

Using RNA sequencing, the differential expression of lncRNA in human HCC cell line with highly metastatic potential (MHCC97H) cells treated with galangin was investigated. Furthermore, H19 expression pattern was also determined in MHCC97H cells following treatment with galangin. In addition, knockdown and overexpression of H19 was performed to analyze the effect of the expression pattern of H19 on cell apoptosis, cell cycle, migration, and invasion in HCC cells. Moreover, the in vivo effect of galangin on tumor development was also determined in nude mice. In order to analyze loss expression of H19 in vivo, clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9) was used.

Results

Total of 50 lncRNAs were significantly differentially expressed in MHCC97H cells treated with galangin. Besides, the expression of H19 was markedly reduced following treatment with galangin in MHCC97H cells. Compared to the Control group, the galangin‐treated group inhibited cell migration and invasion. Knockdown of H19 expression showed increased cell apoptosis and decreased invasion. In addition, RNA‐seq data also identified 161 mRNA which was significantly differentially expressed following treatment with galangin. To further determine the underlying mechanism, p53 protein was analyzed. Notably, the results indicated that knockdown of H19 and miR675 induced the expression of p53, eventually promoting cell apoptosis in MHCC97H cells. These results indicated that galangin promoted cell apoptosis through reduced the expression of H19 and miR675 in MHCC97H cells. The in vivo result showed that compared to the Con, tumor growth was remarkably suppressed with loss expression of H19.

Conclusion

Our data suggested that galangin has a crucial role in hepatocarcinogenesis through regulating the expression pattern of H19.

Long noncoding RNA MAFG-AS1 promotes proliferation, migration and invasion of hepatocellular carcinoma cells through downregulation of miR-6852

Long noncoding RNAs (lncRNAs) have been shown to participate in the development and progression of a number of different types of cancer, including hepatocellular carcinoma (HCC). A recent report has indicated that lncRNA MAFG-antisense 1 (AS1) promotes colorectal cancer. However, the role of MAFG-AS1 in other types of cancer remains unclear. The aim of the present study was to examine the effect of lncRNA MAFG-AS1 in HCC. Based on The Cancer Genome Atlas database and reverse transcription-quantitative PCR results, it was determined that lncRNA MAFG-AS1 expression was increased in HCC tissues and cell lines. Following knockdown of lncRNA MAFG-AS1, a Cell Counting Kit-8 assay and Transwell assay demonstrated that the proliferation, migration and invasion of HCC cell lines were significantly inhibited. It was additionally demonstrated that there was a negative regulatory association between lncRNA MAFG-AS1 and miR-6852. Inhibition of miR-6852 increased proliferation, migration and invasion of HCC cell lines. LncRNA MAFG-AS1 promoted HCC development by dampening miR-6852 function and may thus be a novel target for treating patients with HCC.

Long non-coding RNA TPTEP1 inhibits hepatocellular carcinoma progression by suppressing STAT3 phosphorylation

BACKGROUND

Hepatocellular carcinoma (HCC) is still the most common cause of tumor-related death worldwide and accumulating studies report that long non-coding RNAs (LncRNAs) are closely related with HCC development, metastasis and prognosis. Cisplatinum, a well-known chemotherapeutic drug, has been widely used for treatment of numerous human cancers including HCC. This study aimed to investigate the differential expressions of LncRNAs in HCC cells treated with cisplatinum and its underlying mechanism.

METHODS

The differential expressions of LncRNAs in HCC cells treated with cisplatinum were determined by RNA-seq. The roles of TPTEP1 in HCC development by applying gene function gain and loss analysis in MHCC97H and QYG-7703 cell lines were detected by quantitative real-time polymerase chain reaction (qRT-PCR), cell proliferation, colony formation, cell invasion and flow cytometry assays. The underlying mechanism of TPTEP1 sensitizing hepatocellular carcinoma cells to cisplatinum was examined by RNA-pull down, western blotting, subcellular fractionation, RNA immunoprecipitation and dual luciferase reporter assays. The effect of TPTEP1 on tumorigenesis in vivo was performed with a subcutaneous xenograft mouse model of HCC. In addition, TPTEP1 expression was detected in clinical tumor tissue samples by qRT-PCR.

RESULTS

LncRNA TPTEP1 was highly expressed in cisplatinum-treated HCC cells, which sensitizes hepatocellular carcinoma cell to cisplatinum-induced apoptosis. TPTEP1 overexpression inhibited, while TPTEP1 knockdown promoted HCC cell proliferation, tumorigenicity and invasion. Furthermore, TPTEP1 exerted its tumor suppressing activities by interacting with signal transducer and activator of transcription 3 (STAT3) to inhibit its phosphorylation, homodimerization, nuclear translocation and down-stream genes transcription. Moreover, TPTEP1 overexpression obviously inhibits tumor masses in vivo in a subcutaneous xenograft mouse model of HCC and TPTEP1 is frequently downregulated in HCC tissues, compared to its corresponding pre-tumor tissues.

CONCLUSION

LncRNA TPTEP1 inhibits hepatocellular carcinoma cells progression by affecting IL-6/STAT3 signaling. Taken together, our findings suggest a tumor suppressing role of TPTEP1 in HCC progression and provide a novel understanding of TPTEP1 during the chemotherapy for HCC.

The role of oncogenic Notch2 signaling in cancer: a novel therapeutic target

Deregulated Notch signaling is a key factor thought to facilitate the stem-like proliferation of cancer cells, thereby facilitating disease progression. Four subtypes of Notch receptor have been described to date, with each playing a distinct role in cancer development and progression, therefore warranting a careful and comprehensive examination of the targeting of each receptor subtype in the context of oncogenesis. Clinical efforts to translate the DAPT, which blocks Notch signaling, have been unsuccessful due to a combination of serious gastrointestinal side effects and a lack of complete blocking efficacy. There is therefore a clear need to identify better therapeutic strategies for targeting and manipulating Notch signaling. Notch2 is a Notch receptor that is commonly overexpressed in a range of cancers, and which is linked to a unique oncogenic mechanism. Successful efforts to block Notch2 signaling will depend upon doing so both efficiently and specifically in patients. As such, in the present review we will explore the role of Notch2 signaling in the development and progression of cancer, and we will assess agents and strategies with the potential to effectively disrupt Notch2 signaling and thereby yield novel cancer treatment regimens.

Circular RNA circ-DONSON facilitates gastric cancer growth and invasion via NURF complex dependent activation of transcription factor SOX4

Background

Circular RNAs (circRNAs) are a novel type of noncoding RNAs and play important roles in tumorigenesis, including gastric cancer (GC). However, the functions of most circRNAs remain poorly understood. In our study, we aimed to investigate the functions of a new circRNA circ-DONSON in GC progression.

Methods

The expression of circ-DONSON in gastric cancer tissues and adjacent normal tissues was analyzed by bioinformatics method, qRT-PCR, Northern blotting and in situ hybridization (ISH). The effects of circ-DONSON on GC cell proliferation, apoptosis, migration and invasion were measured by using CCK8, colony formation, EdU, immunofluorescence (IF), FACS and Transwell assays. qRT-PCR and Western blotting were utilized to validate how circ-DONSON regulates SOX4 expression. ChIP, DNA fluorescence in situ hybridization (DNA-FISH) and DNA accessibility assays were used to investigate how circ-DONSON regulates SOX4 transcription. The interaction between circ-DONSON and NURF complex was evaluated by mass spectrum, RNA immunoprecipitation (RIP), pulldown and EMSA assays. Xenograft mouse model was used to analyze the effect of circ-DONSON on GC growth in vivo.

Results

Elevated expression of circ-DONSON was observed in GC tissues and positively associated with advanced TNM stage and unfavorable prognosis. Silencing of circ-DONSON significantly suppressed the proliferation, migration and invasion of GC cells while promoting apoptosis. circ-DONSON was localized in the nucleus, recruited the NURF complex to SOX4 promoter and initiated its transcription. Silencing of the NURF complex subunit SNF2L, BPTF or RBBP4 similarly attenuated GC cell growth and increased apoptosis. circ-DONSON knockdown inhibited GC growth in vivo.

Conclusion

circ-DONSON promotes GC progression through recruiting the NURF complex to initiate SOX4 expression.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-1006-2) contains supplementary material, which is available to authorized users.

The long noncoding RNA cardiac hypertrophy-related factor plays oncogenic roles in hepatocellular carcinoma by downregulating microRNA-211

BACKGROUND

Hepatocellular carcinoma (HCC) is the most major type of primary hepatic cancer. This study aimed to explore the possible oncogenic effects of the long noncoding RNA cardiac hypertrophy-related factor (CHRF) on HCC, as well as the underlying possible mechanism.

METHODS

The expression levels of CHRF and microRNA-211 (miR-211) in HCC tissues and/or cell lines HepG2 and Huh-7 were measured using quantitative reverse transcription polymerase chain reaction. Cell transfection was conducted to change the expression levels of CHRF and miR-211 in cells. Cell viability and apoptosis were assessed using the cell counting kit-8 assay and annexin V-phycoerythrin staining, respectively. The pull-down assay and RNA immunoprecipitation were performed to analyze the association between CHRF and miR-211. The expression of the key factors involving in cell proliferation, cell apoptosis, and epithelial-mesenchymal transition (EMT) process, as well as the phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT) and Wnt/β-catenin pathways, were evaluated by Western blot analysis.

RESULTS

CHRF was highly expressed in HCC tissues and positively associated with the TNM stage, differentiation, and size of tumors. Overexpression of CHRF promoted HepG2 cell viability, proliferation, and EMT process. CHRF knockdown had opposite effects. Moreover, CHRF negatively regulated the expression of miR-21, and miR-21 was a direct target of CHRF. Overexpression of miR-211 reversed the effects of CHRF on HepG2 and Huh-7 cell viability, proliferation, and EMT process. Furthermore, overexpression of CHRF activated the PI3K/AKT and Wnt/β-catenin pathways in HepG2 cells by downregulating miR-211.

CONCLUSION

CHRF played oncogenic roles in HCC. The overexpression of CHRF promoted HepG2 and Huh-7 cell viability, proliferation, and EMT process by downregulating miR-211 and then activating the PI3K/AKT and Wnt/β-catenin pathways.

The Carcinogenic Role of the Notch Signaling Pathway in the Development of Hepatocellular Carcinoma

The Notch signaling pathway, known to be a highly conserved signaling pathway in embryonic development and adult tissue homeostasis, participates in cell fate decisions that include cellular differentiation, cell survival and cell death. However, other studies have shown that aberrant in Notch signaling is pro-tumorigenic, particularly in hepatocellular carcinoma (HCC). HCC is one of the most common malignant tumors in the world and has a high mortality rate. Growing evidence supports that Notch signaling plays a critical role in the development of HCC by regulating the tumor microenvironment, tumorigenesis, progression, angiogenesis, invasion and metastasis. Accordingly, overexpression of Notch is closely associated with poor prognosis in HCC. In this review, we focus on the pro-tumorigenic role of Notch signaling in HCC, summarize the current knowledge of Notch signaling and its role in HCC development, and outline the therapeutic potential of targeting Notch signaling in HCC.

Long non‑coding RNA DANCR promotes nasopharyngeal carcinoma cell proliferation and migration

Aberrant expression of numerous long non‑coding RNAs (lncRNAs) has been reported to be associated with nasopharyngeal carcinoma (NPC). The present study aimed to investigate the expression and function of lncRNA differentiation antagonizing non‑protein coding RNA (DANCR) in NPC pathogenesis. Reverse transcription‑quantitative polymerase chain reaction results suggested that DANCR was significantly upregulated in NPC cells. Overexpression of DANCR promoted 5‑8F cell proliferation and migration, as detected by Cell Counting Kit‑8, colony formation and wound healing assays. DANCR was additionally identified to inhibit apoptosis, as determined by flow cytometric analysis. Furthermore, DANCR knockdown suppressed cell proliferation and migration, and promoted cell apoptosis in SUNE‑1 cell. Western blot analysis suggested that DANCR regulated the phosphorylation of AKT serine/threonine kinase and the protein expression of PTEN in NPC cells. Knockdown of DANCR decreased tumor growth in a xenograft model following subcutaneous injection of SUNE‑1 cells. Collectively, the present results suggested that DANCR regulated the proliferation, migration and apoptosis of NPC cells.

Long Noncoding RNA HOTTIP Promotes Nasopharyngeal Cancer Cell Proliferation, Migration, and Invasion by Inhibiting miR-4301

BACKGROUND The long noncoding RNA (lncRNA) HOTTIP is involved in gastric cancer tumorigenesis, papillary thyroid carcinoma, colorectal cancer, lung adenocarcinoma, and hepatocellular carcinoma, but it is unclear how HOTTIP exerts roles in nasopharyngeal carcinoma (NPC). The present study investigated HOTTIP function during NPC development. MATERIAL AND METHODS HOTTIP levels in cancer specimens and cell lines were analyzed using qRT-PCR. HOTTIP function in NPC was determined by Cell Counting Kit-8 (CCK8) and Transwell assay. RESULTS HOTTIP expression was increased in NPC tissues. Higher levels of HOTTIP are correlated with lower survival in NPC patients. HOTTIP silencing suppressed the proliferation, cell cycle, migration, and invasion of NPC cells. HOTTIP served as a sponge for miR-4301. miR-4301 expression was significantly inhibited by HOTTIP in NPC cells. miR-4301 overexpression dramatically inhibited NPC cell proliferation, migration, and invasion. CONCLUSIONS This study showed that HOTTIP acts as an oncogene in NPC by sponging miR-4301.

LncRNA DUXAP9-206 directly binds with Cbl-b to augment EGFR signaling and promotes non-small cell lung cancer progression

Long noncoding RNAs (lncRNAs) are involved in the pathology of various tumours, including non‐small cell lung cancer (NSCLC). However, the underlying molecular mechanisms of their specific association with NSCLC have not been fully elucidated. Here, we report that a cytoplasmic lncRNA, DUXAP9‐206 is overexpressed in NSCLC cells and closely related to NSCLC clinical features and poor patient survival. We reveal that DUXAP9‐206 induced NSCLC cell proliferation and metastasis by directly interacting with Cbl‐b, an E3 ubiquitin ligase, and reducing the degradation of epidermal growth factor receptor (EGFR) and thereby augmenting EGFR signaling in NSCLC. Notably, correlations between DUXAP9‐206 and activated EGFR signaling were also validated in NSCLC patient specimens. Collectively, our findings reveal the novel molecular mechanisms of DUXAP9‐206 in mediating the progression of NSCLC and DUXAP9‐206 may serve as a potential target for NSCLC therapy.

Overexpression of YEATS4 contributes to malignant outcomes in gastric carcinoma

YEATS domain containing 4 (YEATS4) has functions of chromatin modification and transcriptional regulation and is in a gene-amplified region (12q13) in various human cancers. In this study, we tested whether YEATS4 acts as a cancer-promoting gene through its activation/overexpression in gastric cancer (GC). We analyzed 5 GC cell lines and 135 primary tumor samples of GC, which were curatively resected in our hospital. Overexpression of the YEATS4 protein was frequently detected in GC cell lines (5/5 cell lines, 100%) and primary GC tumor tissues (32/135 cases, 23.7%). Knockdown of YEATS4 inhibited proliferation, migration and invasion of GC cells through NOTCH2 down-regulation in a TP53 mutation-independent manner, and induced apoptosis in wild-type TP53 GC cells. Moreover, knockdown of YEATS4 improved chemosensitivity for CDDP and L-OHP. Overexpression of YEATS4 protein significantly correlated with more aggressive lymphatic invasion, larger tumor size, deeper tumor depth, positive lymph node metastasis and recurrence. Patients with YEATS4-overexpressing tumors had a lower overall survival rate than those with non-expressing tumors. Multivariate analysis demonstrated that YEATS4 was independently associated with poor outcomes. These findings suggest that YEATS4 plays a pivotal role in tumor malignant potential through its overexpression and highlight its usefulness as a prognostic factor and potential therapeutic target in GC.

CircRNA hsa_circ_100395 regulates miR-1228/TCF21 pathway to inhibit lung cancer progression

Circular RNA (circRNA) is shown to participate in various tumors, including lung cancer. Although a few circRNAs involved in lung cancer are reported, whether circRNA negatively regulates lung cancer development remains elusive. In this study, we showed hsa_circ_100395 expression was decreased in lung cancer tissues. Besides, hsa_circ_100395 level was inversely correlated with TNM stage and metastases in lung cancer and low hsa_circ_100395 expression in patients predicted poor prognosis. Overexpression of hsa_circ_100395 dramatically inhibited lung cancer cell proliferation, arrested cell-cycle progression and reduced cell migration and invasion in vitro. Xenograft experiments showed that hsa_circ_100395 overexpression delayed tumor growth in vivo. Mechanistically, we showed hsa_circ_100395 serves as a sponge for miR-1228 targeting TCF21 in lung cancer. Rescue assays indicated that hsa_circ_100395 regulates lung cancer cell proliferation, migration and invasion through modulating miR-1228/TCF21 pathway. Altogether, our study reveals a novel regulatory loop that hsa_circ_100395/miR-1228/TCF21 axis modulates lung cancer development.

ABBREVIATIONS

circRNA: circular RNA; miRNA: microRNA; RNA-FISH: RNA fluorescence in situy bridization; qRT-PCR: Reverse transcription and quantitative real-time PCR.

LncRNA CDKN2B-AS1 promotes tumor growth and metastasis of human hepatocellular carcinoma by targeting let-7c-5p/NAP1L1 axis

Long non-coding RNAs (lncRNAs) show great potential as therapeutic targets in many diseases including hepatocellular carcinoma (HCC). Here, we aimed to investigate the clinical significance and function of lncRNA CDKN2B antisense RNA 1 (CDKN2B-AS1) in HCC. Here, we identified a novel oncogenic lncRNA CDKN2B-AS1, which was highly expressed in HCC and positively associated with large tumor size, microvascular invasion, high tumor grade, advanced tumor stage and reduced survival of HCC patients. CDKN2B-AS1 knockdown inhibited cell proliferation, migration and invasion, and induced G1 arrest and apoptosis of HCC cells in vitro, and CDKN2B-AS1 silencing suppressed tumor growth and metastasis of HCC in vivo. In accordance, CDKN2B-AS1 overexpression accelerated HCC cell growth and metastasis. Mechanistically, CDKN2B-AS1 promoted nucleosome assembly protein 1 like 1 (NAP1L1) expression by sponging let-7c-5p, thereby activated PI3K/AKT/mTOR signaling in HCC cells. Notably, NAP1L1 restoration abolished the effects of CDKN2B-AS1 silencing on HCC cell growth and metastasis. CDKN2B-AS1, an oncogenic lncRNA of HCC, promoted NAP1L1-mediated PI3K/AKT/mTOR signaling by acting as a molecular sponge of let-7c-5p. Our findings indicate that CDKN2B-AS1 may be a potential prognostic biomarker and a candidate target for HCC therapy.

The novel long noncoding RNA u50535 promotes colorectal cancer growth and metastasis by regulating CCL20

Long noncoding RNAs (lncRNAs) have been emerging as master regulators of tumor growth and metastasis, but the functions and underlying mechanisms of lncRNAs in colorectal cancer (CRC) still need to be clarified. Here, we found a novel lncRNA u50535, which was greatly overexpressed in CRC tissues and was associated with poor prognosis in CRC patients. Function studies showed that u50535 was an oncogene in CRC both in vitro and in vivo. In mechanism, through RNA sequencing and rescue assay, we found that u50535 activates CCL20 signaling to promote cell proliferation and migration in CRC. Taken together, these findings suggest that u50535 can promote CRC growth and metastasis and may serve as a potential biomarker in CRC.

LncRNA XIST accelerates cervical cancer progression via upregulating Fus through competitively binding with miR-200a

As one of the commonest gynecological malignancies in the world, cervical cancer brings great threat for public health. Long non-coding RNAs (LncRNAs) have been proved to be closely related to the progression of various cancers, including cervical cancer. As a tumor promoter, lncRNA XIST has been reported in various malignant tumors. In this study, we aim to explore the specific mechanism and biological function of XIST in cervical cancer. At first, the expression levels of XIST were examined in both tissues and cell lines with qRT-PCR. XIST was extremely overexpressed in cervical cancer tissues and cell lines. Kaplan Meier method was then applied to analyze the correlation between XIST expression and overall survival of cervical cancer patients. Loss-of- function assays were designed and conducted to verify the oncogenic function of XIST on cervical cancer progression. Additionally, the results of mechanistic experiments indicated that XIST upregulated Fus through competitively binding with miR-200a. Finally, rescue assays were conducted to demonstrate the regulatory function of XIST-miR-200a-Fus axis in cervical cancer progression. Collectively, XIST served as a ceRNA in cervical cancer progression through modulating miR-200a/Fus axis.