LncRNA SNHG7 promotes the proliferation of esophageal cancer cells and inhibits its apoptosis

Epigenetic modifications in esophageal cancer: An evolving biomarker

Esophageal cancer is a widespread cancer of the digestive system that has two main subtypes: esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EA). In the diverse range of cancer therapy schemes, the side effects of conventional treatments remain an urgent challenge to be addressed. Therefore, the pursuit of novel drugs with multiple targets, good efficacy, low side effects, and low cost has become a hot research topic in anticancer therapy. Based on this, epigenetics offers an attractive target for the treatment of esophageal cancer, where major mechanisms such as DNA methylation, histone modifications, non-coding RNA regulation, chromatin remodelling and nucleosome localization offer new opportunities for the prevention and treatment of esophageal cancer. Recently, research on epigenetics has remained at a high level of enthusiasm, focusing mainly on translating the basic research into the clinical setting and transforming epigenetic alterations into targets for cancer screening and detection in the clinic. With the increasing emergence of tumour epigenetic markers and antitumor epigenetic drugs, there are also more possibilities for anti-esophageal cancer treatment. This paper focuses on esophageal cancer and epigenetic modifications, with the aim of unravelling the close link between them to facilitate precise and personalized treatment of esophageal cancer.

Knockdown of Long Noncoding RNA LINC00240 Inhibits Esophageal Cancer Progression by Regulating miR-26a-5p

Background

Esophageal cancer is the most prevalent digestive system tumor. Due to a lack of characteristic symptoms and early diagnosis, a confirmed esophageal cancer is typically detected at a progressively harmful stage. Therefore, it is critical to investigate the molecular mechanisms governing the formation and progression of esophageal cancer in order to identify new treatment targets for esophageal cancer early detection.

Methods

We first screened the differentially expressed gene LINC00240 in the TCGA database. Multivariate analysis and Cox regression were performed, and a nomogram was constructed for internal validation. The correlation between LINC00240 and immune cells was analyzed using the TIMER database. The possible mechanism of action was explored through GSEA enrichment analysis. Then, in 43 esophageal cancer tissues, paracancour tissues, and cell lines, the LINC00240 expression was found. Transwell assays, CCK-8, and clone formation assays were utilized to assess the impact of LINC00240 on the metastasis of esophageal cancer cells. The binding activity of LINC00240 to downstream miRNAs was assessed using the luciferase reporter gene.

Results

TCGA database showed that LINC00240 expression was increased in cancer tissues compared to adjacent tissues. The C-index of the nomogram is 0.712 (0.666-0.758), and the prediction model has good accuracy. According to the TIMER database, the LINC00240 expression is linked to immune infiltration and may be crucial in encouraging the immune escape of tumor cells. Gene enrichment analysis depicts that LINC00240 could influence the biological events of esophageal cancer by taking part in pathways such as affecting the cell cycle. LINC00240 expression was substantially greater in the plasma of esophageal cancer patients (3.94 ± 1.55) than in the normal control group (2.13 ± 0.89). Plasma expression of LINC00240 was linked to the degree of differentiation (P=0.0345) and TNM stage (P=0.0409). Knocked down LINC00240 inhibited esophageal cancer cells proliferation, lone formation, and invasion. LINC00240 might bind itself to miR-26a-5p and influence its expression. MiR-26a-5p inhibitor can dramatically limit the ability of LINC00240 knockdown on plate colony formation and relocation of esophageal cancerous cells was demonstrated in colony formation and migration experiments.

Conclusion

LINC00240 expression is elevated in esophageal cancerous tissues, and knocking down LINC00240 decreases esophageal cancer cell proliferation, clone formation, invasion, and migration via miR-26a-5p. As a result, LINC00240 could be a novel target for esophageal cancer patients' early diagnosis and treatment.

LINC00667 Promotes Progression of Esophageal Cancer Cells by Regulating miR-200b-3p/SLC2A3 Axis

BACKGROUND

Recently, more and more evidence indicated that the long non-coding RNA was strictly related to the occurrence and progression of human cancers, including esophageal cancer (EC). We observed that LINC00667 was increased in EC, but the function of LINC00667 was unclear. Therefore, the function and potential molecular mechanism of LINC00667 in the progression of EC need to be further studied.

METHODS

Quantitative real-time PCR was used to investigate the levels of LINC00667, miR-200b-3p, and SLC2A3. The levels of protein involved in cell cycle, cell apoptosis, epithelial-mesenchymal transition, as well as SLC2A3 were quantitatived by western blot. The role of LINC00667 in the proliferative, migratory and invasive capabilities of EC cells were measured by cell counting kit-8 assay, EdU assay, flow cytometry assay, wound healing assay and transwell assay, respectively. Interaction between LINC00667 and miR-200b-3p or miR-200b-3p and SLC2A3 were confirmed using a luciferase reporter assay.

RESULTS

In this work, we found that LINC00667 expression was up-regulated in EC cell lines, and LINC00667 knockdown inhibited cell proliferation, migration, and invasion in EC cells. In addition, it showed that LINC00667 functioned as competitive endogenous RNA for miR-200b-3p by the DIANA-LncBase database. Moreover, we used targetscan online software to predict SLC2A3 as a target gene of miR-200b-3p. Subsequently, rescue experiments confirmed that knocking out SLC2A3 could reverse the inhibitory effect of miR-200b-3p on EC cells transfected with sh-LINC00667.

CONCLUSION

Herein, we revealed the novel mechanism of LINC00667 on regulating metastasis-related gene by sponge regulatory axis during EC metastasis. Our results demonstrated that LINC00667 plays a critical role in metastatic EC by mediating sponge regulatory axis miR-200b-3p/SLC2A3. To explore function of LINC00667/miR-200b-3p/SLC2A3 axis may provide an informative biomarker of malignancy and a highly selective anti-EC therapeutic target.

Long non-coding RNA AC087388.1 as a novel biomarker in colorectal cancer

Background

Several investigations have reported diverse roles of long non-coding RNA (lncRNA) in biological processes, tumor development, and progression of colorectal cancer (CRC). In this study, we investigated the lncRNA AC087388.1 tumorigenic role in CRC cells.

Methods

The CRC tissues were collected at the Reza Radiotherapy and Oncology Center, Mashhad, Iran. The human SW-48 and HT-29 CRC cell lines were obtained from the national cell bank of Iran. The cells were cultured according to ATCC (the American Type Culture Collection) recommendations. Quantitative real-time PCR was applied to assess the RNA expression. ShRNA transfection was done to downregulate the target gene. MTT and apoptosis assays were conducted to evaluate cell proliferation and viability, respectively. Colony formation assay, wound healing assay, and invasion assay were applied to determine growth, motility, and invasion of the cells, respectively. ENCORI online tool was used as downstream enrichment analysis.

Results

Forty CRC patients were encompassed in this study. The results demonstrated that the lncRNA SLC16A1-AS1, AC087388.1, and ELFN1-AS1 were significantly overexpressed in the CRC tissues in comparison to their normal counterpart margins. All the lncRNAs have shown significant Area Under Curve (AUC) values in the patients. Downregulation of lncRNA AC087388.1 remarkably decreased the cell proliferation and viability of the CRC cells. In addition, the data demonstrated that the downregulation of lncRNA AC087388.1 significantly suppressed cell growth and colony formation capability in the cells. Also, downregulation of lncRNA AC087388.1 attenuated motility and invasion of CRC cells, and significantly decreased the expression of invasion genes. In-silico functional enrichment analysis indicated that the lncRNA AC087388.1 has contributed to crucial signaling pathways in tumorigenesis such as the p53 and Wnt signaling pathways, apoptosis, and cell cycle.

Conclusions

Altogether, we showed that lncRNA AC087388.1 has an oncogenic role in tumorigenesis of CRC, and it can be considered as a novel diagnostic and prognostic biomarker in CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09282-0.

Oncogenic Roles of Small Nucleolar RNA Host Gene 7 (SNHG7) Long Noncoding RNA in Human Cancers and Potentials

Long noncoding RNAs (lncRNAs) are a class of noncoding transcripts characterized with more than 200 nucleotides of length. Unlike their names, some short open reading frames are recognized for them encoding small proteins. LncRNAs are found to play regulatory roles in essential cellular processes such as cell growth and apoptosis. Therefore, an increasing number of lncRNAs are identified with dysregulation in a wide variety of human cancers. SNHG7 is an lncRNA with upregulation in cancer cells and tissues. It is frequently reported with potency of promoting malignant cell behaviors in vitro and in vivo. Like oncogenic/tumor suppressor lncRNAs, SNHG7 is found to exert its tumorigenic functions through interaction with other biological substances. These include sponging target miRNAs (various numbers are identified), regulation of several signaling pathways, transcription factors, and effector proteins. Importantly, clinical studies demonstrate association between high SNHG7 expression and clinicopathological features in cancerous patients, worse prognosis, and enhanced chemoresistance. In this review, we summarize recent studies in three eras of cell, animal, and human experiments to bold the prognostic, diagnostic, and therapeutic potentials.

Prognostic effect of lncRNA SNHG7 on cancer outcome: a meta and bioinformatic analysis

BACKGROUND

New evidence from clinical and fundamental researches suggests that SNHG7 is involved in the occurrence and development of carcinomas. And the increased levels of SNHG7 are associated with poor prognosis in various kinds of tumors. However, the small sample size was the limitation for the prognostic value of SNHG7 in clinical application. The aim of the present meta-analysis was to conduct a qualitative analysis to explore the prognostic value of SNHG7 in various cancers.

METHODS

Articles related to the SNHG7 as a prognostic biomarker for cancer patients, were comprehensive searched in several electronic databases. The enrolled articles were qualified via the preferred reporting items for systematic reviews and meta-analysis of observational studies in epidemiology checklists. Additionally, an online database based on The Cancer Genome Atlas (TCGA) was further used to validate our results.

RESULTS

We analyzed 2418 cancer patients that met the specified criteria. The present research indicated that an elevated SNHG7 expression level was significantly associated with unfavorable overall survival (OS) (HR = 2.45, 95% CI: 2.12-2.85, p <0.001). Subgroup analysis showed that high expression levels of SNHG7 were also significantly associated with unfavorable OS in digestive system cancer (HR = 2.31, 95% CI: 1.90-2.80, p <0.001) and non-digestive system cancer (HR = 2.67, 95% CI: 2.12-3.37, p <0.001). Additionally, increased SNHG7 expression was found to be associated with tumor stage and progression (III/IV vs. I/II: HR = 1.76, 95% CI: 1.57-1.98, p <0.001). Furthermore, elevated SNHG7 expression significantly predicted lymph node metastasis (LNM) (HR = 1.98, 95% CI: 1.74-2.26, p <0.001) and distant metastasis (DM) (HR = 2.49, 95% CI: 1.88-3.30, p <0.001) respectively. No significant heterogeneity was observed among these studies. SNHG7 was significantly upregulated in four cancers and the elevated expression of SNHG7 predicted shorter OS in four cancers, worse DFS in five malignancies and worse PFI in five carcinomas based on the validation using the GEPIA on-line analysis tool.

CONCLUSIONS

The present analysis suggests that elevated SNHG7 is significantly associated with unfavorable OS, tumor progression, LNM and DM in various carcinomas, and may be served as a promising biomarker to guide therapy for cancer patients.

Polymorphisms in lncRNA MIR2052HG and susceptibility to breast cancer in Chinese population

Background: Published studies based on pharmacokinetics have explored the relationship between the lncRNA MIR2052HG and the prognosis of breast cancer (BC) resistance and recurrence. However, the underlying association of MIR2052HG SNPs with BC development remains unclear.

Methods: Combining bioinformatics and databases, SNPs (Single Nucleotide Polymorphisms) in the MIR2052HG gene were screened, and SNPs in the lncRNA MIR2052HG were selected for genotyping among 504 Chinese Han patients and 505 healthy controls, which were frequency-matched for age (±2 years). Logistic regression analysis was used to explore the association between MIR2052HG SNPs and the BC risk. Interactions between the MIR2052HG SNPs and reproductive factors were further evaluated using the multifactor dimensionality reduction (MDR) method. qRT–PCR was performed to detect MIR2052HG expression in individuals with different genotypes of rs34841297. The target miRNA, miR-4456 of MIR2052HG rs34841297 was predicted by websites and confirmed by performing dual luciferase gene reporter assays. CCK-8 and Transwell experiments were designed to explore the effects of miR-4456 on the proliferation, invasion and migration of BC cells.

Results: In this study, nine SNPs were screened. After adjusting for age, menarche age, menopausal status, number of pregnancies, history of abortions, breast feeding history and family history of BC, the results of the logistic regression analysis showed the rs34841297 A/- gene polymorphism was positively correlated with the incidence of BC. Compared with the AA genotype, patients with the A-+-- genotype of rs34841297 at age<50 years, and menarche age<14 years, Premenopausal status, history of abortion, no history of breastfeeding and no family history of tumors in first-degree relatives had an increased risk of BC. MDR results revealed that individuals with rs34841297 - (homozygous deletion) of the A allele who were not menopausal and had no history of breastfeeding had a higher risk of BC. qRT–PCR results revealed that homozygous deletion (1.68±1.37) of the rs34841297 A- genotype resulted in higher MIR2052HG expression than the heterozygous deletion genotype (0.95±0.94) and wild AA genotype (0.26±0.12). Binding between MIR2052HG and miR-4456 was occurred when rs34841297 carried the AA genotype. Moreover, preliminary functional studies indicated that the overexpression of miR-4456 increased the proliferation, invasion and migration of BC cells.

Conclusion: Our study showed that the MIR2052HG gene polymorphism may be related to BC susceptibility, and the MIR2052HG rs34841297 A/- genotype may probably affect the proliferation, invasion and migration of BC cells by modulating the interactions with of miR-4456.

LncRNA SNHG7 Regulates Gastric Cancer Progression by miR-485-5p

Background

Long noncoding ribonucleic acids (lncRNAs) were closely related to the development of gastric cancer. This study investigated the effect of SNHG7 on gastric cancer progression and its potential molecular mechanism.

Methods

SNHG7 and microRNA-485-5p (miR-485-5p) expressions in gastric cancer tissues and cells were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell counting kit-8 (CCK-8), wound healing, and transwell experiments were used to detect cell proliferation, migration, and invasion. The dual luciferase reporter assay, RNA immunoprecipitation (RIP) experiment, and Pearson's correlation analysis were used to confirm the relationship between SNHG7 and miR-485-5p.

Results

SNHG7 expression was increased in human gastric cancer tissues and cells. Knockdown of SNHG7 could notably inhibit the gastric cancer cells proliferation, migration, and invasion. The dual-luciferase reporter assay and RIP experiments proved that miR-485-5p was a direct target of SNHG7. At the same time, further experiments demonstrated that miR-485-5p inhibition reversed the suppression of SNHG7 knockdown on gastric cancer cells proliferation, migration, and invasion.

Conclusions

SNHG7 knockdown could hamper gastric cancer progression via inhibiting miR-485-5p expression, providing a novel understanding for gastric cancer development.

Knockdown of lncRNA TUC338 inhibits esophageal cancer cells migration and invasion

Background

Long non-coding RNAs (lncRNAs) are firmly identified with the event and improvement of tumors. Therefore, elucidating the functions and mechanisms of related lncRNAs is significant for understanding the occurrence and advancement of tumors. The recently discovered lncRNA TUC338 has been shown to play the role of an oncogene in an assortment of tumors. Be that as it may, the articulation and elements of lncRNA TUC338 in esophageal cancer are as yet hazy. This investigation plans to explain the capacities and related molecular mechanisms of lncRNA TUC338 in esophageal malignancy.

Methods

Firstly, the expression of TUC338 in 50 instances of esophageal disease tissues and nearby tissues was detected by fluorescence reckonable PCR, and correlations with the clinic pathological characteristics of patients was further analyzed. Then, a lentiviral interference vector was designed and transfected into an esophageal cancer cell line, and knockdown was verified by fluorescence quantitative PCR. The effects of TUC338 knockdown on the proliferation, clone formation, and migration and infringement of esophageal malignancy cells were tested utilizing the CCK-8 assay, clone formation experiments, and Transwell experiments. Western blot detected the expression of invasion-related proteins.

Results

Fluorescence reckonable PCR exhibit that TUC338 was exceptionally communicated in esophageal cancer tissues, and was significantly related with metastasis and TNM stage in tolerant. Functional experiments showed that in esophageal disease cell lines, knocking down the declaration of TUC338 significantly inhibited cell multiplication, clone development, and intrusion and movement. Further experiments on molecular mechanisms showed that knocking down TUC338 inhibited statement of N-cadherin and vimentin in cells.

Conclusions

TUC338 is exceptionally communicated in esophageal malignancy tissues and can regulate cell proliferation and invasion.

LncRNA GIHCG Promotes the Development of Esophageal Cancer by Modulating miR-29b-3p/ANO1 Axis

Background

Esophageal cancer is one of the most frequent cancers with a higher mortality worldwide. Although many long non-coding RNAs (LncRNAs) are reported to play important roles in the progression of esophageal cancer, the function of lncRNA GIHCG in esophageal cancer remains unclear.

Methods

The expression of GIHCG in esophageal cancer tissues and cancer cell lines was detected by qRT-PCR. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8) assay, EdU staining assay and colony formation assay. Cell invasion and migration were measured by transwell assay. Cell apoptosis was detected by a flow cytometer. Luciferase reporter assay and RIP assay were used to determine the interaction between GIHCG and miR-29b-3p, and their subsequent regulation of anoctamin 1 (ANO1). The expression of ANO1 in esophageal cancer tissues and cell lines was detected by Western blot. The effect of GIHCG/miR-29b-3p in tumor formation was assessed by the xenograft nude mice model in vivo.

Results

GIHCG was significantly upregulated in esophageal cancer tissues and relevant cancer cell lines. Downregulation of GIHCG significantly inhibited the growth, colony formation, invasion, migration and induced apoptosis of esophageal cancer cells in vitro. Bioinformatic analysis and RIP assay determined that GIHCG was a sponge of miR-29b-3p, and ANO1 was a direct target of miR-29b-3p. Moreover, functional experiments showed that GIHCG upregulated ANO1 expression by directly sponging miR-29b-3p. Furthermore, in vivo experiment revealed that knockdown of GIHCG significantly inhibited tumor growth in nude mice.

Conclusion

Our study revealed that lncRNA GIHCG promoted the progression of esophageal cancer by targeting the miR-29b-3p/ANO1 axis, suggesting that GIHCG might be a novel therapeutic target for esophageal cancer.

Long noncoding RNA HEIH depletion depresses esophageal carcinoma cell progression by upregulating microRNA-185 and downregulating KLK5

Numerous studies have reported the association of long non-coding RNAs (lncRNAs) in cancers, yet the function of lncRNA high expressed in hepatocellular carcinoma (HEIH) in esophageal carcinoma (EC) has seldom been explored. Here, we aimed to explore the mechanism of HEIH on EC via microRNA-185 (miR-185)/kallikrein-related peptidase 5 (KLK5) modulation. Cancer and non-tumoral tissues were collected, in which HEIH, miR-185 and KLK5 expression were detected, as well as their correlations. Also, the relation between the prognosis of EC patients and HEIH/miR-185/KLK5 expression was clarified. EC cells (KYSE-30 and TE-1) were screened for subsequent gain- and loss-of-function assays and their biological functions were further monitored. Tumor volume and weight in EC mice were also measured. Results from this study indicated that HEIH and KLK5 were elevated and miR-185 was declined in EC. The positive correlation was seen in HEIH and KLK5 expression, while the negative correlation was observed in HEIH or KLK5 and miR-185 expression. High HEIH and KLK5 indicated worse prognosis and high miR-185 suggested better prognosis of EC patients. Depleting HEIH or restoring miR-185 suppressed the malignant phenotypes of EC cells, and delayed tumor growth in EC mice. HEIH was found to bind with miR-185 to regulate KLK5 expression. Overexpressing KLK5 alone promoted EC cell progression while up-regulating miR-185 reversed such effects on EC cells. Collectively, we reveal that HEIH depletion dampens EC progression by upregulating miR-185 and downregulating KLK5, which provides novel treatments for EC.

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 noncoding RNA SNHG12 induces proliferation, migration, epithelial-mesenchymal transition, and stemness of esophageal squamous cell carcinoma cells via post-transcriptional regulation of BMI1 and CTNNB1

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors around the world. Numerous studies have revealed the function of long noncoding RNAs (lncRNAs) in cancers, including ESCC. In this study, lncRNA small nucleolar RNA host gene 12 (SNHG12), mainly distributed in ESCC cell cytoplasm, was overexpressed in ESCC specimens and CD133⁺ cells. In CD133^‐ ESCC cells, SNHG12 overexpression promoted cell proliferation, migration, epithelial–mesenchymal transition (EMT), and stemness and SNHG12 silencing led to opposite results. Furthermore, SNHG12 sequestered miR‐6835‐3p and induced the proto‐oncogene, polycomb ring finger (BMI1). SNHG12 also enhanced the stability of CTNNB1, the mRNA encoding β‐catenin, via recruiting insulin‐like growth factor 2 mRNA‐binding protein 2 (IGF2BP2) in ESCC. Rescue assays indicated that CTNNB1 and BMI1 were targets for SNHG12 to regulate ESCC cell proliferation, migration, EMT, and stemness. Furthermore, SOX4 (sex‐determining region Y‐box 4) bound with the SNHG12 promoter to transcriptionally activate SNHG12 in ESCC. Finally, in vivo data showed SNHG12 knockdown retarded tumorigenesis and metastasis in ESCC. In summary, SNHG12 induces proliferation, migration, EMT, and stemness of ESCC cells via post‐transcriptional regulation of BMI1 and CTNNB1, indicating that targeting SNHG12 might be a novel target for ESCC treatment.

High expression of lncRNA-SNHG7 is associated with poor prognosis in hepatocellular carcinoma

Expression of long non-coding RNA SNHG7 (lncRNA-SNHG7) and its clinical significance in hepatocellular carcinoma (HCC) were explored. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression level of lncRNA-SNHG7 in cancer tissues. Kaplan-Meier curves and multivariate Cox proportional models were used to study the impact on clinical outcome. Expression of lncRNA-SNHG7 was much higher in cancer tissues than that in para-cancer tissues. The lncRNA-SNHG7 expression was correlated with tumor number, lymph node metastasis and clinical stage (P<0.05). In addition, HCC patients with higher lncRNA-SNHG7 expression had significantly poorer progression-free survival time and overall survival time (P<0.001). Both univariate analysis and multivariate analysis indicated that high expression of lncRNA-SNHG7 was an independent predictor of poor prognosis in HCC. LncRNA-SNHG7 might contribute to the development of HCC and serve as a clinical biomarker and a therapeutic target for HCC patients.

LncRNA SNHG7 promotes the proliferation of nasopharyngeal carcinoma by miR-514a-5p/ELAVL1 axis

Background

Nasopharyngeal carcinoma (NPC), with distinct geographical distribution, has gathered public attention. Despite that radiotherapy and chemotherapy are applied to treat NPC, cell metastasis still cannot be avoided. Numerous works have elucidated that lncRNAs are essential players in the development of multiple cancers. LncRNA SNHG7 has been reported as a contributing factor in the occurrence of certain cancers, but its mechanism in NPC deserves further investigation. The purpose of the study is to figure out the role and molecular regulation mechanism of SNHG7 in NPC.

Methods

The role of SNHG7 in NPC was verified by CCK-8, colony formation, EdU staining, western blot and capase-3 assays. The interactions between SNHG7/ELAVL1 and miR-514a-5p were confirmed by RNA pull down, RT-qPCR, RIP and luciferase reporter assays.

Results

SNHG7 was upregulated in NPC cells, and absence of SNHG7 suppressed cell proliferation as well as promoted cell apoptosis in NPC. Furthermore, SNHG7 was confirmed to bind with miR-514a-5p and negatively modulate miR-514a-5p expression. Besides, miR-514a-5p was found to be able to bind with ELAVL1 and negatively regulate ELAVL1 mRNA and protein expressions. In the end, rescue assays demonstrated that the miR-514a-5p deficiency restored the NPC progression inhibited by SNHG7 silence, and ELAVL1 partly counteracted the restoration caused by miR-514a-5p inhibitor in HNE1 cells.

Conclusions

LncRNA SNHG7 promotes the proliferation and migration of nasopharyngeal carcinoma by miR-514a-5p/ ELAVL1 axis.

Long non-coding RNA SNHG7 promotes malignant melanoma progression through negative modulation of miR-9

Long non-coding small nucleolar RNA host gene 7 (lncRNA SNHG7) was verified to act as an onco-gene in human cancers. Nevertheless, the role of SNHG7 in malignant melanoma remains elusive. The present study showed an increase of SNHG7 expression in malignant melanoma tissues and cell lines. Besides, SNHG7 knockdown inhibited proliferation and migration in malignant melanoma cells. Bioinformatics analysis demonstrated that SNHG7 functions as a molecular sponge for miR-9 in biological behavior of melanoma cells. And miR-9 could inhibit the expression of PI3KR3 by binding with the 3'-UTR. Furthermore, PI3KR3, pAKT, cyclin D1 and Girdin expression was down-regulated after SNHG7 knockdown by siRNA. In addition, SNHG7 knockdown decreased xenograft growth in vivo. Taken together, this research demonstrated that SNHG7 was an oncogene in malignant melanoma, providing a novel insight for the pathogenesis and new potential therapeutic target for malignant melanoma.

An Emerging Class of Long Non-coding RNA With Oncogenic Role Arises From the snoRNA Host Genes

The small nucleolar RNA host genes (SNHGs) are a group of long non-coding RNAs, which are reported in many studies as being overexpressed in various cancers. With very few exceptions, the SNHGs (SNHG1, SNHG3, SNHG5, SNHG6, SNHG7, SNHG12, SNHG15, SNHG16, SNHG20) are recognized as inducing increased proliferation, cell cycle progression, invasion, and metastasis of cancer cells, which makes this class of transcripts a viable biomarker for cancer development and aggressiveness. Through our literature research, we also found that silencing of SNHGs through small interfering RNAs or short hairpin RNAs is very effective in both in vitro and in vivo experiments by lowering the aggressiveness of solid cancers. The knockdown of SNHG as a new cancer therapeutic option should be investigated more in the future.

LncRNA CRNDE and lncRNA SNHG7 are Promising Biomarkers for Prognosis in Synchronous Colorectal Liver Metastasis Following Hepatectomy

Purpose

Synchronous colorectal liver metastasis (SCLM) had limited availability of tools to predict survival and tumor recurrence. LncRNA CRNDE and lncRNA SNHG7 have been proven to be closely related to cancer progression. However, the predictive value of lncRNA CRNDE and lncRNA SNHG7 in cancer prognosis is still unclear. The purpose of this study was to investigate whether lncRNA CRNDE and lncRNA SNHG7 could be used as promising biomarkers for prognosis prediction of SCLM patients who underwent hepatectomy.

Methods

The expression profile of lncRNA CRNDE and lncRNA SNHG7 in serum of SCLM patients was examined by qRT-PCR. The relationship between lncRNA expression and clinicopathological characteristics was analyzed. The Cox proportional-hazards regression model and Kaplan-Meier analysis were performed to analyze the association between lncRNA expression and overall survival (OS) and tumor recurrence of SCLM patients.

Results

Levels of lncRNA CRNDE and lncRNA SNHG7 in patients who underwent recurrence or death were significantly higher than that of patients with recurrence-free or survival (P<0.01). Both lncRNA CRNDE high level and lncRNA SNHG7 high level showed a significant correlation with differentiation of primary tumor, invasion depth of primary focus, lymph node metastases, number of liver metastases, and liver metastasis grade. High levels of lncRNA CRNDE or lncRNA SNHG7 predicted shorter recurrence time, shorter OS time, higher recurrence rate and lower OS rate. Furthermore, lncRNA CRNDE and lncRNA SNHG7 were independent risk factors for high recurrence and poor OS in SCLM underwent hepatectomy.

Conclusion

Taken together, lncRNA CRNDE and lncRNA SNHG7 could be promising biomarkers for prediction of OS and tumor recurrence in SCLM underwent hepatectomy.

Long Noncoding RNA SNHG7, a Molecular Sponge for microRNA-485, Promotes the Aggressive Behavior of Cervical Cancer by Regulating PAK4

Purpose

A long noncoding RNA called small nucleolar RNA host gene 7 (SNHG7) is known to be a key regulator of biological processes in multiple human cancer types. In this study, our aims were to determine the expression status of SNHG7 in cervical cancer, to figure out the detailed roles of SNHG7 in cervical cancer cells, and to identify the mechanism underlying the activity of SNHG7 in cervical cancer.

Methods

Reverse-transcription quantitative PCR was performed to measure SNHG7 expression in cervical cancer. A Cell Counting Kit-8 assay, flow-cytometric analysis, cell migration and invasion assays, and a tumor xenograft experiment were conducted to respectively determine the effects of SNHG7 on cervical cancer cell proliferation, apoptosis, migration, and invasion in vitro and tumor growth in vivo.

Results

SNHG7 was found to be markedly upregulated in cervical cancer tissues and cell lines. Higher SNHG7 expression significantly correlated with FIGO stage, lymph node metastasis, the depth of cervical invasion, and shorter overall survival in patients with cervical cancer. Functional experiments indicated that a SNHG7 knockdown attenuated proliferation, migration, and invasiveness and promoted apoptosis of cervical cancer cells in vitro. The SNHG7 knockdown also slowed tumor growth in vivo. Further investigation showed that SNHG7 acts as a competing endogenous RNA for microRNA-485 (miR-485) in cervical cancer cells, and the inhibitory actions of the SNHG7 knockdown on the malignant phenotype were reversed by miR-485 inhibition. P21-activated kinase 4 (PAK4) was identified as a direct target gene of miR-485 in cervical cancer, and PAK4 expression was promoted by SNHG7.

Conclusion

SNHG7 functions as an oncogenic RNA in cervical cancer, competitively binds to miR-485, and thereby upregulates PAK4. This SNHG7–miR-485–PAK4 regulatory network may provide insights into the pathogenesis of cervical cancer, and can help in the identification of novel diagnostic and therapeutic approaches for cervical cancer.

SNHG7 Facilitates Glioblastoma Progression by Functioning as a Molecular Sponge for MicroRNA-449b-5p and Thereby Increasing MYCN Expression

BACKGROUND AND AIMS

Long noncoding RNA (small nucleolar RNA host gene 7) has been reported to be involved in multiple malignancies and acts as an oncogene. However, the potential mechanism of small nucleolar RNA host gene 7 in glioblastoma is rarely known. In this study, we attempted to elucidate the biological effects of small nucleolar RNA host gene 7 and the possible molecular mechanism in glioblastoma.

METHODS

The expression level of small nucleolar RNA host gene 7 in glioblastoma tissues and corresponding tumor cell lines was evaluated by using quantitative real-time polymerase chain reaction. Bioinformatics analyses and dual-luciferase reporter gene assay were conducted to verify the correlation among small nucleolar RNA host gene 7, miR-449b-5p, and MYCN. The role of small nucleolar RNA host gene 7 on cell viability, migration, and invasion was measured.

RESULTS

Small nucleolar RNA host gene 7 expression was markedly increased in glioblastoma tumor tissue. Small nucleolar RNA host gene 7 can sponge miR-449b-5p and negatively regulate miR-449b-5p expression. MiR-449b-5p was remarkably repressed in glioblastoma tissues. Reduction of miR-449b-5p reversed the repressive effects of small nucleolar RNA host gene 7 knockdown on cellular behaviors in glioblastoma. In addition, miR-449b-5p can directly bind with MYCN. Compared with normal samples, MYCN expression was increased. The MYCN expression was negatively related to miR-449b-5p expression while positively related to small nucleolar RNA host gene 7 expression. Rescue experiments revealed that MYCN overexpression reversed the repressive role of small nucleolar RNA host gene 7 knockdown on viability, migration, and invasion of U251 cells.

CONCLUSION

In summary, our results demonstrated that small nucleolar RNA host gene 7 regulates glioblastoma proliferation, migration, and invasion via regulating miR-449b-5p and its target gene MYCN, thereby providing a potential therapeutic target for glioblastoma.

Potential Prognostic and Diagnostic Values of CDC6, CDC45, ORC6 and SNHG7 in Colorectal Cancer

Background

Colorectal cancer (CRC) is a common human malignancy. The aims of this study are to investigate the gene expression profile of CRC and to explore potential strategy for CRC diagnosis, therapy and prognosis.

Methods

We use affy and Limma package of Bioconductor R to do differential expression genes (DEGs) and differential expression lncRNAs (DELs) analysis from the gene datasets (GSE8671, GSE21510, GSE32323, GSE39582 and TCGA) respectively. Then, DEGs were analyzed by GO and KEGG pathway and Kaplan-Meier survival curve and Cox regression analyses were used to find aberrantly expressed genes associated with survival outcome of CRC patients. Real-time PCR assay was used to verify the aberrantly expressed genes expression in CRC samples.

Results

306 up-regulation and 213 down-regulation common DEGs were found. A total of 485 DELs were identified, of which 241 up-regulated and 244 down-regulated. Then, GO and KEGG pathway analyses showed that DEGs were involved in cell cycle, mineral absorption, DNA replication, and Nitrogen metabolism. Among them, Kaplan-Meier survival curve and Cox regression analyses revealed that CDC6, CDC45, ORC6 and SNHG7 levels were significantly associated with survival outcome of CRC patients. Finally, real-time PCR assay was used to verify that the CDC6, CDC45, ORC6 and SNHG7 expression were up-regulated in 198 CRC samples compared with the expression levels in individual-matched adjacent mucosa samples.

Conclusion

CDC6, CDC45, ORC6 and SNHG7 are implicated in CRC initiation and progression and could be explored as potential diagnosis, therapy and prognosis targets for CRC.

SNHG7 accelerates cell migration and invasion through regulating miR-34a-Snail-EMT axis in gastric cancer

Small nucleolar RNA host gene 7 (SNHG7) is a newly recognized oncogenic Long non-coding RNA (lncRNA) in most human cancers. In gastric cancer, SNHG7 has been suggested to enhance cell proliferation and suppressed apoptosis through down-regulating P15 and P16 expression, but the effect of SNHG7 on gastric cancer cell migration and invasion was still unknown. In our study, we aimed to estimate the relationship between SNHG7 expression and clinical and pathological characteristics, and explore the effect of SNHG7 on gastric cancer cell migration and invasion. In our study, the levels of SNHG7 expression in gastric cancer tissues and cell lines were severally higher than in normal adjacent tissues and gastric mucosal epithelial cells. Moreover, high SNHG7 expression was positively correlated with TNM stage, depth of invasion, lymph-node metastasis and distant metastasis in gastric cancer patients. Furthermore, the multivariate Cox proportional hazard analysis further showed high SNHG7 expression was an independent poor prognostic factor for overall survival in gastric cancer patients. The studies in vitro revealed that SNHG7 directly binds to miR-34a and negatively regulates miR-34a expression, and SNHG7 enhances gastric cancer cell migration and invasion through suppressing miR-34a-Snail-EMT axis. In conclusion, SNHG7 functions as oncogenic lncRNA in gastric cancer and may be a potential therapeutic target for gastric cancer patients.Abbreviations: lncRNA: Long non-coding RNA; SNHG7: Small nucleolar RNA host gene 7; EMT: Epithelial mesenchymal transition; TNM: Tumor-Lymph Node-Metastasis.

Long non-coding small nucleolar RNA host genes in digestive cancers

Although long noncoding RNAs (lncRNAs) do not have protein coding capacities, they are involved in the pathogenesis of many types of cancers, including hepatocellular carcinoma, cervical cancer, and gastric cancer. Notably, the roles of lncRNAs are vital in nearly every aspect of tumor biology. Long non‐coding small nucleolar RNA host genes (lnc‐SNHGs) are abnormally expressed in multiple cancers, including urologic neoplasms, respiratory tumors, and digestive cancers, and play vital roles in these cancers. These host genes could participate in tumorigenesis by regulating proliferation, migration, invasion and apoptosis of tumor cells. This review focuses on the overview of the roles that lnc‐SNHGs play in the formation and progression of digestive cancers.

Long non-coding RNA small nucleolar RNA host gene 7 is upregulated and promotes cell proliferation in thyroid cancer

Thyroid cancer (THCA) is one of the most common types of endocrine cancer worldwide. However, the mechanisms underlying THCA progression have not been fully elucidated. Recent studies have demonstrated that long non-coding RNAs (lncRNAs) are dysregulated in human diseases, and are involved in regulating various biological processes. Furthermore, several reports have indicated that lncRNAs serve important roles in THCA. In the present study, a dataset from The Cancer Genome Atlas was used to analyze the expression levels and the clinical information of small nucleolar RNA host gene 7 (SNHG7) in THCA. Starbase was used to construct the competing endogenous RNA network. The Molecule Annotation System was used to analyze the data from Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases. Furthermore, cell proliferation and cell cycle assays were used to detect the functions of SNHG7 in THCA. The present study revealed for the first time, to the best of our knowledge, that SNHG7 is markedly upregulated in THCA samples following analysis of The Cancer Genome Atlas datasets. SNHG7 expression was higher in advanced stage compared with early stage THCA samples. In addition, high expression levels of SNHG7 were associated with shorter survival times in THCA patients compared with low expression levels. Bioinformatics analysis revealed that SNHG7 was associated with the processes of ‘protein translation’, ‘viral life cycle’, ‘RNA processing’, ‘mRNA splicing’, ‘histone ubiquitination’, ‘endoplasmic reticulum-to-Golgi vesicle-mediated transport’, ‘sister chromatid cohesion’, ‘DNA damage checkpoint regulation’, ‘translation’ and ‘the spliceosome’. Additionally, knockdown of SNHG7 significantly inhibited thyroid cancer cell proliferation and cell cycle progression in vitro. Taken together, the results obtained in the present study suggested that SNHG7 may serve as a novel therapeutic and prognostic target for THCA.

Metformin Suppresses Hypopharyngeal Cancer Growth by Epigenetically Silencing Long Non-coding RNA SNHG7 in FaDu Cells

Local recurrence after therapy remains a challenging problem for hypopharyngeal cancer (HPC) due to the chemotherapy resistance. Metformin is associated with reduced cancer risk through promoting global DNA methylation in cancer cells by controlling S-adenosylhomocysteine (SAHH) activity. However, the mechanisms by which metformin inhibits HPC remain elusive. In this study, we aim to investigate the role of metformin in HPC and illustrate the mechanism by which metformin regulates long non-coding RNAs (lncRNAs) expression. CCK-8 and annexin-V/PI double staining were performed to analyze the cell viability and apoptosis. LncRNA microarray analysis, QPCR, methylation specific PCR, Western blot and RNA Immunoprecipitation were performed to analyze the molecular mechanism, Here, we report that metformin inhibits FaDu cell proliferation in time- and dose-dependent manner by suppressing lncRNA SNHG7. Further investigations revealed that SNHG7 interacted with SAHH and metformin decreased SNHG7 expression by activating SAHH activity. Increased SAHH activity resulted in upregulating DNMT1 expression, leading to hypermethylation of SNHG7 promotor. In addition, upregulation of SNHG7 was associated with advanced stage. The patients with high SNHG7 have lower overall survival than that of with low SNHG7. Interestingly, SNHG7 levels were higher in taxol resistant patients than in taxol sensitive patients. Metformin sensitizes FaDu cells to taxol and irradiation through decreasing SNHG7. In conclusion, our recent study demonstrates that metformin inhibits FaDu cell proliferation by decreasing SNHG7 expression via SAHH-mediated DNA methylation. These findings indicate that combined metformin with paclitaxel or irradiation would be a novel therapeutic strategy to overcome resistance and prevent recurrence in HPC.