lncRNA SNHG7 affects malignant tumor behaviors through downregulation of EZH2 in uveal melanoma cell lines

LncRNA SNHG7 promotes non-small cell lung cancer progression and cisplatin resistance by inducing autophagic activity

Background

Cisplatin (DDP) is among the most widely used chemotherapeutic drugs for non-small cell lung cancer (NSCLC), yet the frequent emergence of chemoresistance serves as a major barrier to the treatment of this tumor type. Long non-coding RNAs (lncRNAs) have recently been shown to influence the ability of cells to resist particular chemotherapy drugs. The present study was developed to explore the role of the lncRNA SNHG7 as a regulator of NSCLC cell chemosensitivity.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to measure SNHG7 expression in NSCLC tissues from patients that were sensitive/resistant to DDP, correlations between SNHG7 expression levels and the patients' clinicopathological characteristics were assessed, and the prognostic relevance of SNHG7 expression was examined via the Kaplan-Meier approach. In addition, SNHG7 expression was assessed in NSCLC cell lines that were DDP-sensitive or -resistant, while western blotting and immunofluorescence staining were employed to detect autophagy-associated protein expression in A549, A549/DDP, HCC827, and HCC827/DDP cells. NSCLC cell chemoresistance was quantified via the Cell Counting Kit-8 (CCK-8) assay approach, and flow cytometry was used to detect the apoptotic death of these tumor cells. The chemosensitivity of xenograft tumors in vivo was further assessed to validate the functional importance of SNHG7 as a regulator of NSCLC DDP resistance.

Results

Relative to paracancerous tissues, NSCLC tumors exhibited SNHG7 upregulation, and this lncRNA was further upregulated in DDP-resistant patients compared to chemosensitive patients. Consistently, higher SNHG7 expression levels were correlated with worse patient survival outcomes. DDP-resistant NSCLC cells were also found to exhibit higher levels of SNHG7 expression than chemosensitive cells, and knocking down this lncRNA enhanced the sensitivity of these cells to DDP treatment, resulting in impaired proliferation and higher rates of apoptotic death. Knocking down SNHG7 was also sufficient to suppress microtubule associated protein 1 light chain 3 beta (LC3B) and Beclin1 protein levels and promote p62 upregulation in vitro. The silencing of this lncRNA additionally inhibited the resistance of NSCLC xenograft tumors to DDP treatment in vivo.

Conclusions

SNHG7 can promote malignant behaviors and DDP resistance in NSCLC cells at least partly via the induction of autophagic activity.

Comparative outcomes of single-incision laparoscopic, mini-laparoscopic, four-port laparoscopic, three-port laparoscopic, and single-incision robotic cholecystectomy: a systematic review and network meta-analysis

Benign gallbladder diseases are common in surgery department, and the laparoscopic cholecystectomy (LC) is the gold standard procedure for benign diseases of gallbladder. Laparoscopic cholecystectomy is conventionally performed using four laparoscopic ports. However, the clinical application of different LCs is equivocal and there is no comprehensive comparison to explore which surgical options could benefit patients with benign gallbladder diseases. A network meta-analysis (NMA) to evaluate the efficacy of the different LCs could benefit patients with benign gallbladder diseases by comprehensive comparison. A systematic literature search was performed using PubMed, Embase, and Cochran Library. Totally, 17 randomized controlled trials (RCTs) (n = 1627) met study selection criteria and were incorporated in this NMA study. The first ranking probabilities of the five surgical options to alleviate postoperative pain scores were: 54.4% for single-incision robotic cholecystectomy (SIRC), 25.2% for single-incision laparoscopic cholecystectomy (SALC), and 24.9% for mini-laparoscopic cholecystectomy (Mini). The first ranking probabilities for reducing postoperative complications in the surgical options were: 61.3% for three-port laparoscopic cholecystectomy and 21.8% for four-port laparoscopic cholecystectomy. The first ranking probabilities for reducing hospital stay(days) in the surgical options were: 32.3% for SIRC, 29.0% for three-port laparoscopic cholecystectomy and 19.8% for four-port laparoscopic cholecystectomy. The first ranking probabilities for reducing operation time showed that the three-port technique had the shortest operation time, followed by three-port laparoscopic cholecystectomy (51.3%), four-port laparoscopic cholecystectomy (26.8%), and mini-laparoscopic cholecystectomy (21.6%). Our study found that the optimal surgical plan for different outcomes varies, making it difficult to give a comprehensive recommendation. Three-port laparoscopic cholecystectomy and four-port laparoscopic cholecystectomy may be the best options in terms of reducing surgical complications and operative time. Meanwhile, SIRC is the best options for relieving postoperative pain relief. SIRC and three-port laparoscopic cholecystectomy can reduce hospital stay (days) compared other LCs.

Comprehensive Analysis of Molecular Clusters and Prognostic Signature Based on m7G-related LncRNAs in Esophageal Squamous Cell Carcinoma

N7-Methylguanosine (m7G) and long non-coding RNAs (lncRNAs) have been widely reported to play an important role in cancer. However, there is little known about the relationship between m7G-related lncRNAs and esophageal squamous cell carcinoma (ESCC). In this study, we aimed to find new potential biomarkers and construct an m7G-related lncRNA prognostic signature for ESCC. Three molecular clusters were identified by consensus clustering of 963 m7G-related lncRNAs, of which cluster B is preferentially related to poorer prognosis, higher immune and stromal scores, higher mRNA levels of immune checkpoints, and higher immune infiltrate level. We constructed a robust and effective m7G-related lncRNA prognostic signature (m7G-LPS, including 7 m7G-related prognostic lncRNAs) and demonstrated its prognostic value and predictive ability in the GEO and TCGA cohorts. The risk score was able to serve as an independent risk factor for patients with ESCC and showed better prediction than the traditional clinical risk factors. The immune score, stromal score, the infiltration level of immune cells and expression of immune checkpoints were significantly higher in the high-risk subgroup compared to the low-risk subgroup. The establishment of nomogram further improved the performance of m7G-LPS and facilitated its clinical application. Finally, we used GTEx RNA-seq data and qRT-PCR experiments to verify the expression levels of 7 m7G-related lncRNAs. To a certain degree, m7G-lncRNAs can be used as prognostic markers and therapeutic targets for ESCC patients.

The Roles and Mechanisms of lncRNAs in Liver Fibrosis

Long non-coding RNAs (lncRNAs) can potentially regulate all aspects of cellular activity including differentiation and development, metabolism, proliferation, apoptosis, and activation, and benefited from advances in transcriptomic and genomic research techniques and database management technologies, its functions and mechanisms in physiological and pathological states have been widely reported. Liver fibrosis is typically characterized by a reversible wound healing response, often accompanied by an excessive accumulation of extracellular matrix. In recent years, a range of lncRNAs have been investigated and found to be involved in several cellular-level regulatory processes as competing endogenous RNAs (ceRNAs) that play an important role in the development of liver fibrosis. A variety of lncRNAs have also been shown to contribute to the altered cell cycle, proliferation profile associated with the accelerated development of liver fibrosis. This review aims to discuss the functions and mechanisms of lncRNAs in the development and regression of liver fibrosis, to explore the major lncRNAs involved in the signaling pathways regulating liver fibrosis, to elucidate the mechanisms mediated by lncRNA dysregulation and to provide new diagnostic and therapeutic strategies for liver fibrosis.

Do Extracellular RNAs Provide Insight into Uveal Melanoma Biology?

Simple Summary

The study of RNAs in the extracellular environment in physiological and pathological conditions has become a growing field of research with intriguing applications in diagnostics and prognostics. Such extracellular RNAs are passively or actively released by all cells into biological fluids to spread biological signals to other cells. The perturbation of such RNA-based cell-to-cell communications in cancer can be easily identified by molecular analysis of liquid biopsies, even if source cells secreting RNAs are often elusive. In uveal melanoma (UM), extracellular RNAs can be assayed in serum, plasma, and vitreous and aqueous humor. In this review, we explore the possibility that extracellular RNA alterations in UM could partially match with RNA dysregulations observed in tumor tissues and provide information to better understand UM biology.

Abstract

Uveal melanoma (UM) is the most common primary intraocular malignant tumor in adults, showing a high mortality due to metastasis. Although it is considered a rare disease, a growing number of papers have reported altered levels of RNAs (i.e., coding and non-coding RNAs) in cancerous tissues and biological fluids from UM patients. The presence of circulating RNAs, whose dysregulation is associated with UM, paved the way to the possibility of exploiting it for diagnostic and prognostic purposes. However, the biological meaning and the origin of such RNAs in blood and ocular fluids of UM patients remain unexplored. In this review, we report the state of the art of circulating RNAs in UM and debate whether the amount and types of RNAs measured in bodily fluids mirror the RNA alterations from source cancer cells. Based on literature data, extracellular RNAs in UM patients do not represent, with rare exceptions, a snapshot of RNA dysregulations occurring in cancerous tissues, but rather the complex and heterogeneous outcome of a systemic dysfunction, including immune system activity, that modifies the mechanisms of RNA delivery from several cell types.

Clinicopathological and prognostic value of long noncoding RNA SNHG7 in cancers: a meta-analysis and bioinformatics

The long intergenic non-coding RNA SNHG7 has been reported to be abnormally expressed in many types of cancer, the results remain controversial. In this study, a meta-analysis was performed to evaluate the clinicopathologic and prognostic value of SNHG7 in cancers. Electronic databases of PubMed, Web of Science, Cochrane Library and Embase were used to search relevant studies. A combined hazard ratio (HR) and its corresponding 95% confidence interval (CI) were used to assess the association between SNHG7 expression and prognosis in cancer patients. Pooled odds ratio (OR) and 95% CI were calculated to elaborate the association between SNHG7 expression and clinicopathological features in cancers. Besides, the data from The Cancer Genome Atlas (TCGA) dataset was used to validate the results. In total, eighteen studies compromising 1303 participants were enrolled in this analysis. The pooled results showed increased SNHG7 expression could predict unfavorable overall survival (OS) (HR = 1.75, 95%CI = 1.52–2.02, P = 0.000). Analysis stratified by follow-up time, cancer types, analysis types, sample sizes and cut off further verified the prognostic value of SNHG7. Additionally, elevated SNHG7 expression was correlated with TNM stage (OR: 3.31, 95%CI = 2.29–4.80, P = 0.000), lymph node metastasis (OR = 3.32, 95%CI = 1.61–6.83, P = 0.004), and tumor differentiation (OR = 1.92, 95%CI = 1.22–3.03, P =0.005) in patients with cancers. Excavation of TCGA dataset valuated that SNHG7 was upregulated in some cancers and predicted worse OS, which partially confirmed our results in this meta-analysis.

The Role of LncRNAs in Uveal Melanoma

Uveal melanoma (UM) is an intraocular cancer tumor with high metastatic risk. It is considered a rare disease, but 90% of affected patients die within 15 years. Non-coding elements (ncRNAs) such as long non-coding RNAs (lncRNAs) have a crucial role in cellular homeostasis maintenance, taking part in many critical cellular pathways. Their deregulation, therefore, contributes to the induction of cancer and neurodegenerative and metabolic diseases. In cancer, lncRNAs are implicated in apoptosis evasion, proliferation, invasion, drug resistance, and other roles because they affect tumor suppressor genes and oncogenes. For these reasons, lncRNAs are promising targets in personalized medicine and can be used as biomarkers for diseases including UM.

The Tumorigenic Properties of EZH2 are Mediated by MiR-26a in Uveal Melanoma

Background: The polycomb group protein enhancer of zeste homolog 2 (EZH2) has been found to be highly expressed in various tumors, and microRNA-26a (miR-26a) is often unmodulated in cancers. However, the functions of these two molecules in uveal melanoma (UM) and their relationships have not been reported.

Methods: We explored the effects of the miR-26a–EZH2 axis in UM by examining the levels of miR-26a and EZH2. The EZH2 levels in various tumor types and the correlations between EZH2 levels and overall survival and disease-free survival were reanalyzed. The binding of miR-26a to the 3′-untranslated region of EZH2 mRNA was measured using the luciferase reporter assay. The regulation of EZH2 gene expression by miR-26a was also identified, and the effect of elevated EZH2 expression on UM cell function was further examined. Results: miR-26a was downregulated and EZH2 was upregulated in UM cells. Overexpression of miR-26a inhibited cell proliferation, and knockdown of EZH2 suppressed cell growth. EZH2 was a direct target of miR-26a in UM cells. The knockout of EZH2 mimicked the tumor inhibition of miR-26a in UM cells, whereas the reintroduction of EZH2 abolished this effect. In addition, a network of EZH2 and its interacting proteins (UBC, CDK1, HDAC1, SUZ12, EED) was found to participate in miR-26a-mediated tumor progression.

Conclusion: The newly identified miR-26a–EZH2 axis may be a potential target for the development of treatment strategies for UM.

CircRNA circ_POLA2 is Upregulated in Acute Myeloid Leukemia (AML) and Promotes Cell Proliferation by Suppressing the Production of Mature miR-34a

Purpose

CircRNA circ_POLA2 has been reported as an oncogene in lung cancer, while its role in other malignancies is unknown. This study aimed to explore the role of circ_POLA2 in acute myeloid leukemia (AML).

Methods

The expression levels of circ_POLA2, mature miR-34a and miR-34a precursor in bone marrow mononuclear cells (BMMNCs) from AML patients (n = 50) and healthy controls (n = 50) were determined by RT-qPCR. Correlations among them were analyzed by Pearson’s correlation coefficient. Overexpression of circ_POLA2 was achieved in AML cell lines, followed by the measurement of the expression levels of mature miR-34a and miR-34a precursor. The role of circ_POLA2 and miR-34a in regulating AML cell proliferation was assessed by CCK-8 assay.

Results

Circ_POLA2 was upregulated in AML and inversely correlated with mature miR-34a, but not miR-34a precursor. In AML cells, overexpression of circ_POLA2 decreased the expression levels of mature miR-34a, but not miR-34a precursor. Cell proliferation analysis showed that the overexpression of miR-34a attenuated the effects of overexpression of circ_POLA2 on cell proliferation.

Conclusion

Circ_POLA2 is upregulated in AML and promotes cell proliferation by suppressing the production of mature miR-34a.

LncRNA LINC00518 Acts as an Oncogene in Uveal Melanoma by Regulating an RNA-Based Network

Simple Summary

Uveal melanoma (UM) is the most frequent primary tumor of the eye in adults. Although molecular alterations on protein-coding genes have been associated with the development of UM, the role of non-coding RNAs and their competitive endogenous networks remain poorly investigated. Starting from a computational analysis on UM expression dataset deposited in The Cancer Genome Atlas, we identified the long non-coding RNA LINC00518 as a potential oncogene. We then experimentally evaluated LINC00518 and its supposed RNA signaling in human biopsies and in vitro functional assays. The results obtained suggest that LINC00518, under potential transcriptional control by MITF, regulates an RNA–RNA network promoting cancer-related processes (i.e., cell proliferation and migration). These findings open the way to the characterization of the unknown RNA signaling associated with UM and pave the way to the exploitation of a potential target for RNA-based therapeutics.

Abstract

Uveal melanoma (UM) is the most common primary intraocular malignant tumor in adults; little is known about the contribution of non-coding RNAs (ncRNAs) to UM pathogenesis. Competitive endogenous RNA (ceRNA) networks based on RNA–RNA interactions regulate physiological and pathological processes. Through a combined approach of in silico and experimental biology, we investigated the expression of a set of long non-coding RNAs (lncRNAs) in patient biopsies, identifying LINC00518 as a potential oncogene in UM. The detection of LINC00518 dysregulation associated with several in vitro functional assays allowed us to investigate its ceRNA regulatory network and shed light on its potential involvement in cancer-related processes, such as epithelial to mesenchymal transition (EMT) and CoCl₂-induced hypoxia-like response. In vitro transient silencing of LINC00518 impaired cell proliferation and migration, and affected mRNA expression of LINGO2, NFIA, OTUD7B, SEC22C, and VAMP3. A “miRNA sponge” and “miRNA protector” model have been hypothesized for LINC00518-induced regulation of mRNAs. In vitro inhibition of MITF suggested its role as a potential activator of LINC00518 expression. Comprehensively, LINC00518 may be considered a new oncogene in UM and a potential target for RNA-based therapeutic approaches.

LINC01094/miR-577 axis regulates the progression of ovarian cancer

Background

Long intergenic non-coding RNA 01094 (LINC01094) is probably a novel regulator in cancer biology. This study aimed to probe into the function and mechanism of LINC01094 in ovarian cancer (OC).

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) assay was utilized to measure LINC01094 and miR-577 expressions in OC tissues and cell lines. Western blot was used to examine the expressions of epithelial-mesenchymal transition (EMT)-related proteins, β-catenin, c-Myc and cyclin D1. Cell counting kit-8 (CCK-8) and Transwell assays were used to detect the proliferation, migration and invasion of SKOV3 and 3AO cells, respectively. Eventually, dual-luciferase reporter gene assay was employed to detect the regulatory relationship between miR-577 and LINC01094.

Results

LINC01094 expression was elevated in OC tissues and cell lines. High LINC01094 expression was associated with higher FIGO stage, lymph node metastasis and the shorter overall survival rate in patients with OC. Meanwhile, LINC01094 knockdown inhibited OC cell proliferation, migration, invasion and EMT. In addition, miR-577 was demonstrated to be a direct downstream target of LINC01094 in OC and inhibition of miR-577 reversed the biological effects of LINC01094 knockdown on OC cells. Additionally, LINC01094 / miR-577 axis regulated the expressions of β-catenin, c-Myc and cyclin D1 in OC cells.

Conclusion

LINC01094 promotes the proliferation, migration, invasion and EMT of OC cells by adsorbing miR-577.

The Role of Non-Coding RNAs in Uveal Melanoma

Simple Summary

The development of uveal melanoma is a multifactorial and multi-step process, in which abnormal gene expression plays a key role. Recently, several studies have highlighted the role of non-coding RNAs in the progression of uveal melanoma by affecting different signaling pathways. As important agents in the regulation of genes, non-coding RNAs have enormous potential to open up therapeutic pathways, predict response to treatment, and anticipate patient outcome for uveal melanoma. This review aims to provide a comprehensive view of what we know about ncRNAs in uveal melanoma currently.

Abstract

Uveal melanoma (UM) is the most common primary intraocular tumor in adulthood. Approximately 50% of patients develop metastatic disease, which typically affects the liver and is usually fatal within one year. This type of cancer is heterogeneous in nature and is divided into two broad groups of tumors according to their susceptibility to develop metastasis. In the last decade, chromosomal abnormalities and the aberrant expression of several signaling pathways and oncogenes in uveal melanomas have been described. Recently, importance has been given to the association of the mentioned deregulation with the expression of non-coding RNAs (ncRNAs). Here, we review the different classes of ncRNAs—such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs)—and their contribution to the development of UM. Special attention is given to miRNAs and their regulatory role in physiopathology and their potential as biomarkers. As important agents in gene regulation, ncRNAs have a huge potential for opening up therapeutic pathways, predicting response to treatment, and anticipating patient outcome for UM.

The role of long noncoding RNA SNHG7 in human cancers (Review)

Long non-coding RNAs (lncRNAs) have been demonstrated to serve important roles in a variety of human tumor types. The lncRNA small nucleolar RNA host gene 7 (SNHG7) is associated with a variety of cancer types, such as esophageal cancer, breast cancer and gastric neoplasia. Based on previous studies that examined SNHG7 expression in tumors, it has become clear that SNHG7 modulates tumorigenesis and cancer progression by acting as a competing endogenous RNA. SNHG7 can sponge tumor-suppressive microRNAs and regulate downstream signaling pathways. In addition, overexpression of SNHG7 is associated with the clinical characteristics of patients with cancer by regulating cellular proliferation, invasion and metastasis and by inhibiting apoptosis via a variety of mechanisms of action. The function of SNHG7 in tumorigenesis and cancer progression indicates that it can potentially act as a novel therapeutic target or a diagnostic biomarker for cancer therapy or detection, respectively.

Long non-coding RNA NPBWR1-2 affects the development of ovarian cancer via multiple microRNAs

Ovarian cancer has a high incidence rate and mortality in gynaecologic malignancies. Epithelial ovarian cancer (EOC) accounts for >95% of ovarian cancer cases. Most of the patients with EOC are difficult to diagnose in early stage. The aim of the present study was to compare the long non-coding (lnc)RNA expression profiles of five ovarian cancer cell lines (IGROV1, A2780, SKOV3, ES2, and Hey) and an ovarian epithelial cell line (IOSE80) in order to identify differentially expressed lncRNAs and their associated microRNAs (miRNAs). The expression profiles of lncRNAs and mRNAs in these cell lines were determined by microarray gene analysis and reverse transcription-quantitative PCR. lncRNA neuropeptides B and W receptor 1–2 (NPBWR1-2) overexpression was induced in the SKOV3 cell line. Cell viability, proliferation, migration, invasion and apoptosis were evaluated using MTT, colony-formation, Transwell and flow cytometry assays, respectively. The microarray results indicated that several lncRNAs were differentially expressed in the five ovarian cancer cell lines compared with the normal ovarian epithelial cell line. Compared with IOSE80, lncRNA NPBWR1-2 was downregulated by more than two-fold in all five ovarian cancer cell lines. Moreover, NPBWR1-2 overexpression in the SKOV3 cell line decreased cell viability, inhibited proliferation, migration and invasion, and promoted apoptosis compared with the control cells. A total of 20 miRNAs, which are involved in tumorigenesis and development, were predicted to be associated with NPBWR1-2 by bioinformatics analysis. The results of the present study suggest that lncRNA NPBWR1-2 affects the occurrence and development of ovarian cancer via multiple miRNAs, providing a theoretical basis for the development of novel clinical treatments.