MicroRNA-1297 inhibits proliferation and promotes apoptosis in gastric cancer cells by downregulating CDC6 expression

LncRNA THUMPD3-AS1 promotes invasion and EMT in gastric cancer by regulating the miR-1297/BCAT1 pathway

Long noncoding RNA (lncRNA) plays crucial roles in the development of gastric cancer (GC); however, studies of their mechanisms of action are needed to determine their clinical value. The aim of this study is to explore the effects and mechanisms of THUMPD3-AS1 in GC. Elevated levels of THUMPD3-AS1 were observed in GC and demonstrated a significant positive correlation with poor prognosis. Functionally, THUMPD3-AS1 promoted GC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) and induced tumor growth in vivo. THUMPD3-AS1 exerts its regulatory function on BCAT1 through competitive binding with miR-1297. Further investigations confirmed that both THUMPD3-AS1 and miR-1297 interact with BCAT1. These findings suggest that THUMPD3-AS1 promotes GC invasion and EMT by regulating the miR-1297/BCAT1 pathway, indicating that THUMPD3-AS1 may serve as a biomarker and therapeutic target for GC.

Expression and Regulatory Mechanisms of MicroRNA in Cholesteatoma: A Systematic Review

Cholesteatoma is a temporal bone disease characterized by dysfunctions of keratinocytes. MicroRNAs (miRNAs) are evolutionary conserved noncoding RNAs that regulate mRNA expression. They can be packaged into exosomes and transported to target cells that can be used in the future therapy of cholesteatoma. This study aimed to collect knowledge on the role of miRNAs and exosomal miRNAs in cholesteatoma and was conducted according to the PRISMA guidelines for systematic reviews. Four databases were screened: Pubmed/MEDLINE, Web of Science, Scopus, and the Cochrane Library. The last search was run on the 6th of June 2023. We included full-text original studies written in English, which examined miRNAs in cholesteatoma. The risk of bias was assessed using the Office of Health Assessment and Translation (OHAT) Risk of Bias Rating Tool, modified for the needs of this review. We identified 118 records and included 18 articles. Analyses revealed the downregulation of exosomal miR-17 as well as miR-10a-5p, miR-125b, miR-142-5p, miR34a, miR-203a, and miR-152-5p and the overexpression of exosomal miR-106b-5p as well as miR-1297, miR-26a-5p, miR-199a, miR-508-3p, miR-21-3p, miR-584-5p, and miR-16-1-3p in cholesteatoma. The role of differentially expressed miRNAs in cholesteatoma, including cell proliferation, apoptosis, the cell cycle, differentiation, bone resorption, and the remodeling process, was confirmed, making them a potential therapeutic target in this disease.

m6A-related lncRNAs predict prognosis and indicate cell cycle in gastric cancer

Background: N6-methyladenosine (m6A) modification is a common epigenetic methylation modification of RNA, which plays an important role in gastric carcinogenesis and progression by regulating long non-coding RNA (lncRNA). This study is aimed to investigate the potential prognostic signatures of m6A -related lncRNAs in STAD. Methods: The m6A-related lncRNAs with the most significant impact on gastric cancer prognosis in the TCGA database were identified by bioinformatics and machine learning methods. The m6A-related lncRNA prognostic model (m6A-LPS) and nomogram was constructed by Cox regression analysis with the minimum absolute contraction and selection operator (LASSO) algorithm. The functional enrichment analysis of m6A-related lncRNAs was also investigated. The miRTarBase, miRDB and TargetScan databases were utilized to establish a prognosis-related network of competing endogenous RNA (ceRNA) by bioinformatics methods. The correlation of AL391152.1 expressions and cell cycle were experimentally testified by qRT-PCR and flow cytometry. Results: In total, 697 lncRNAs that were identified as m6A-related lncRNAs in GC samples. The survival analysis showed that 18 lncRNAs demonstrated prognostic values. A risk model with 11 lncRNAs was established by Lasso Cox regression, and can predict the prognosis of GC patients. Cox regression analysis and ROC curve indicated that this lncRNA prediction model was an independent risk factor for survival rates. Functional enrichment analysis and ceRNA network revealed that the nomogram was notably associated with cell cycle. qRT-PCR and flow cytometry revealed that downregulation of GC m6A-related lncRNA AL391152.1 could decrease cyclins expression in SGC7901 cells. Conclusion: A m6A-related lncRNAs prognostic model was established in this study, which can be applied to predict prognosis and cell cycle in gastric cancer.

Replication Stress: A Review of Novel Targets to Enhance Radiosensitivity-From Bench to Clinic

DNA replication is a process fundamental in all living organisms in which deregulation, known as replication stress, often leads to genomic instability, a hallmark of cancer. Most malignant tumors sustain persistent proliferation and tolerate replication stress via increasing reliance to the replication stress response. So whilst replication stress induces genomic instability and tumorigenesis, the replication stress response exhibits a unique cancer-specific vulnerability that can be targeted to induce catastrophic cell proliferation. Radiation therapy, most used in cancer treatment, induces a plethora of DNA lesions that affect DNA integrity and, in-turn, DNA replication. Owing to radiation dose limitations for specific organs and tumor tissue resistance, the therapeutic window is narrow. Thus, a means to eliminate or reduce tumor radioresistance is urgently needed. Current research trends have highlighted the potential of combining replication stress regulators with radiation therapy to capitalize on the high replication stress of tumors. Here, we review the current body of evidence regarding the role of replication stress in tumor progression and discuss potential means of enhancing tumor radiosensitivity by targeting the replication stress response. We offer new insights into the possibility of combining radiation therapy with replication stress drugs for clinical use.

LncRNA SNHG6 knockdown inhibits cisplatin resistance and progression of gastric cancer through miR-1297/BCL-2 axis

Cisplatin (DDP) resistance is a huge obstacle to gastric cancer (GC) treatment. Long non-coding RNAs (lncRNAs) have been manifested to exert pivotal functions in GC development. Herein, we aimed to explore the functional impact of lncRNA small nucleolar RNA host gene 6 (SNHG6) on DDP resistance and progression of GC. Quantitative real-time PCR (qRT-PCR) assay or Western blotting was performed to detect the expression of SNHG6, microRNA(miR)-1297, and epithelial-mesenchymal transition (EMT)-related factors and B-Cell Lymphoma 2 (Bcl-2) in DDP-resistant GC cells. Half inhibition concentration (IC50) to DDP, clonogenicity, apoptosis and invasion were examined via CCK-8 assay, colony formation assay, flow cytometry and Transwell assay, respectively. Target association between miR-1297 and SNHG6 or BCL-2 was demonstrated via dual-luciferase reporter assay or RIP assay. Xenograft models in nude mice were formed to investigate role of SNHG6 in vivo. We found that SNHG6 and BCL-2 were up-regulated, while miR-1297 expression was declined in GC tissues and DDP-resistant cells. Moreover, depletion of SNHG6 or gain of miR-1297 could repress DDP resistance, proliferation and metastasis of DDP-resistant cells, which was weakened by miR-1297 inhibition or BCL-2 overexpression. Besides, SNHG6 positively regulated BCL-2 expression by sponging miR-1297. Furthermore, SNHG6 knockdown repressed GC tumor growth in vivo. In a word, lncRNA SNHG6 knockdown had inhibitory effects on DDP resistance and progression of GC by sponging miR-1297, highlighting its potential in GC treatment.

Circ_PGPEP1 Serves as a Sponge of miR-1297 to Promote Gastric Cancer Progression via Regulating E2F3

BACKGROUND

Circular RNA (circRNA) is a special kind of noncoding RNA that plays a vital function in the progression of gastric cancer (GC). However, the role of a new circRNA, circ_PGPEP1, in GC is unclear.

AIMS

Exploring the role and mechanism of circ_PGPEP1 in GC progression.

METHODS

The expression levels of circ_PGPEP1, miR-1297, and E2F transcription factor 3 (E2F3) were determined using quantitative real-time PCR. Flow cytometry, colony formation assay, MTT assay, and transwell assay were used to evaluate cell cycle, apoptosis, proliferation, migration, and invasion. The protein levels of apoptosis-related markers and E2F3 were measured by western blot analysis. The interaction between circ_PGPEP1 and miR-1297 or miR-1297 and E2F3 was confirmed by dual-luciferase reporter assay. In addition, animal experiments were performed to assess the effect of circ_PGPEP1 on GC tumor growth in vivo.

RESULTS

Circ_PGPEP1 was a highly expressed circRNA in GC. Loss-of-function experiment indicated that circ_PGPEP1 silencing could induce cell cycle arrest and apoptosis, while inhibit proliferation, migration, and invasion in GC cells. MiR-1297 could be sponged by circ_PGPEP1, and its expression was downregulated in GC. MiR-1297 inhibitor could reverse the negatively regulation of circ_PGPEP1 knockdown on GC progression. Furthermore, we also found that E2F3 could be targeted by miR-1297, and its expression was positively regulated by circ_PGPEP1. Overexpression of E2F3 could invert the inhibitory effect of miR-1297 on GC progression. Animal experiments suggested that silenced circ_PGPEP1 could reduce GC tumor growth.

CONCLUSION

Our research showed that circ_PGPEP1 might serve as a potential biomarker for GC.

Dual role of microRNA-1297 in the suppression and progression of human malignancies

MicroRNAs (miRNAs) are endogenous, non-coding, single-stranded and tiny RNAs that modulate several biological functions, more importantly, the pathophysiology of numerous human cancers. They are bound with target mRNAs and thereby regulate gene expression at post-transcriptional levels. MiRNAs can either trigger cancer progression as an oncogene or alleviate it as a tumor suppressor. Abnormal expression of microRNA-1297 (miR-1297) has been noticed in several human cancers suggesting a distinct role for the miRNA in tumorigenesis. More specifically, it is both up-regulated and down-regulated in various cancers suggesting that it can act as both tumor suppressor and oncogene. This review systematically highlights the different roles of miR-1297 in the pathophysiology of human cancers, explains the mechanisms underlying miR-1297-mediated tumorigenesis, and discusses its potential prognostic, diagnostic, and therapeutic importance.

Increased CDC6 Expression Associates With Poor Prognosis in Patients With Clear Cell Renal Cell Carcinoma

Background

CDC6 (Cell division control protein 6), located at chromosome 17q21.3, plays an important role in the early stage of DNA replication and has unique functions in various malignant tumors. Here, we evaluate the relationship between CDC6 expression and oncology outcomes in patients with clear cell renal cell carcinoma (ccRCC).

Methods

A retrospective analysis of 118 ccRCC patients in Affiliated Hospital of Nantong University from 2015 to 2017 was performed. Triplicate tissue microarrays (TMA) were prepared from formalin-fixed and paraffin-embedded specimens. Immunohistochemistry (IHC) was conducted to evaluate the relationship between CDC6 expression and standard pathological features and prognosis. The RNA sequencing data and corresponding clinical information were acquired from the TCGA database. GSEA was used to identify signal pathways related to CDC6. Cox regression analysis was used to assess independent prognostic factors. In addition, the relationship between CDC6 and immunity was also investigated.

Results

The results of Kaplan–Meier curve indicated that the OS of the patients with high expression of CDC6 was shorter than that of the patients with low CDC6 expression. Integrating the TCGA database and IHC staining, the results showed that CDC6 in ccRCC tissue was obviously up-regulated compared with adjacent normal kidney tissue. The results of Logistic regression analysis demonstrated that ccRCC patients with high expression of CDC6 are more likely to develop advanced disease than ccRCC patients with low CDC6 expression. The results of GSEA showed that the high expression of CDC6 was related to multiple signaling pathways. As for immunity, it was also related to TMB, immune checkpoint molecules, tumor microenvironment and immune infiltration. There were significantly correlations with CDC6 and immune cell infiltration levels and tumor microenvironment. The results of further results of the TCGA database showed that CDC6 was obviously related to immune checkpoint molecules and immune cells.

Conclusions

Increased expression of CDC6 is a potentially prognostic factor of poor prognosis in ccRCC patients.

Long noncoding RNA DLGAP1-AS1 promotes the progression of glioma by regulating the miR-1297/EZH2 axis

Dysregulated lncRNAs have been implicated in a plethora of tumors, including glioma. One such oncogenic lncRNAs that has been reported in several cancers is the lncRNA DLGAP1 antisense RNA 1 (DLGAP1-AS1). This study seeks to characterize the expression of DLGAP1-AS1 in glioma tissues, which we found to be raised in both glioma samples and cell lines. Functional experiments revealed that DLGAP1-AS1 promoted in vitro glioma cell invasion, migration and proliferation. DLGAP1-AS1 was found to function as a miR-1297 sponge, based on information from luciferase reporter assays, RNA pull-down assays and publicly available online databases. miR-1297 was in turn found to functionally target EZH2. DLGAP1-AS1 modulated EZH2 expressions through miR-1297 sponging. Glioma progression appears to be supported DLGAP1-AS1 -promoted activation of the miR-1297/EZH2 axis. The components of this axis may function as therapeutic targets for glioma.

Clinical crosstalk between microRNAs and gastric cancer (Review)

Globally, there were over 1 million new gastric cancer (GC) patients in 2018 and GC has become the sixth most common cancer worldwide. GC caused 783,000 deaths worldwide in 2018, making it the third most deadly cancer type. miRNAs are short (~22 nucleotides in length) non‑coding RNA molecules, which can regulate gene expression passively at a post‑transcriptional level. There are more and more in‑depth studies on miRNAs. There are numerous conclusive evidences that there is an inseparable link between miRNAs and GC. miRNAs can affect the entire process of GC, including the oncogenesis, development, diagnosis, treatment and prognosis of GC. Although many miRNAs have been linked to GC, few can be applied to clinical practice. This review takes the clinical changes of GC as a clue and summarizes the miRNAs related to GC that have confirmed the mechanism of action in the past three years. Through in‑depth study and understanding of the mechanism of those miRNAs, we predict their possible clinical uses, and suggest some new insights to overcome GC.

LncRNA NEAT1 promotes gastric cancer progression via miR-1294/AKT1 axis

Long non-coding RNAs (lncRNAs) were reported to promote the development of gastric cancer (GC). Nuclear-enriched abundant transcript 1 (NEAT1) played a great role in diverse cancers, but the mechanism of NEAT1 in GC remains indistinct. NEAT1 and AKT1 were distinctly up-regulated and miR-1294 was down-regulated in GC tissues and cells. Cell proliferation and metastasis were refrained but apoptosis was promoted in GC cells after knockdown of NEAT1. NEAT1 negatively regulated miR-1294 expression, and the miR-1294 inhibitor reverted the si-NEAT1-induced effect on GC cells. NEAT1 modulated AKT1 expression through miR-1294, and the si-NEAT1-induced effect was relieved by AKT1. NEAT1 affected phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway via regulating miR-1294 and AKT1. NEAT1 could modulate cell proliferation, apoptosis, and metastasis in GC cells by regulating the PI3K/AKT/mTOR signaling pathway via the miR-1294/AKT1 axis, showing the great potential for NEAT1 as a valid biomarker in the progression and treatment of GC.

Mechanism of miR-98 inhibiting tumor proliferation and invasion by targeting IGF1R in diabetic patients combined with colon cancer

Expression level of miR-98 in diabetic colon cancer (CRC) tissues and the regulation mechanism of colon cancer cell proliferation and invasion ability were studied. Forty patients with type 2 diabetes mellitus complicated with colon cancer, 40 colon cancer patients, and 40 patients with diabetic colonoscopy were enrolled between January 2017 and January 2018. Real-time quantitative PCR was used to detect the expression level of miR-98. After SW480 cells were transfected with miR-98 mimics or control simulants, the proliferation of cancer cells was detected by MTT assay, and the invasion ability of cancer cells was detected by Transwell cell invasion assay. The dual luciferase assay was used to detect the binding relationship between miR-98 and IGF1R. Western blot analysis was used to detect the expression of IGF1R protein in tumor tissues of patients with diabetes mellitus and colon cancer. Compared with diabetic patients, the expression level of miR-98 was decreased in colon cancer patients. Compared with tumor tissues of colon cancer patients, the expression level of miR-98 was significantly decreased in diabetic colon cancer tissues. Compared with the commonly cultured colon cancer SW480 cells, the expression level of miR-98 was significantly decreased in SW480 cells cultured under high glucose conditions. Increased expression of miR-98 inhibits colon cancer cell proliferation and invasion. miR-98 can target and bind to IGF1R and inhibit its expression level. IGF1R is upregulated in diabetic colon cancer tissue. miR-98 inhibits proliferation and invasion of diabetic colon cancer by targeting IGF1R. The expression level of miR-98 in diabetic colon cancer tissues is lower than that in colon cancer tissues. miR-98 can inhibit the proliferation and invasion of colon cancer cells by targeting the target gene IGF1R. miR-98 may be a potential biological target for the treatment of patients with diabetes and colon cancer.

miR-874 inhibits gastric cancer cell proliferation by targeting SPAG9

Background

microRNAs (miRNAs) play essential roles in the development and progression of gastric cancer (GC). Although aberrant miR-874 expression has been reported in various human cancers, its role in GC remains obscure.

Methods

miR-874 expression was assessed by real-time quantitative polymerase chain reaction (RT-qPCR) in 62 matched GC and adjacent normal tissues, as well as in GC cell lines and immortalized human gastric epithelial cells. CCK8 assay, colony formation assay, and flow cytometry were used to assess the role of miR-874 in GC cell proliferation and apoptosis in vitro. Additionally, to determine the effects of miR-874 on GC cell proliferation and apoptosis in vivo, BALB/c nude mice were injected with GC cells transfected with a miR-874 mimic. The role of miR-874 in SPAG9 expression was assessed by luciferase assay, Western blotting, and RT-qPCR.

Results

miR-874 was downregulated in GC cell lines and tissues. miR-874 overexpression in GC cells led to inhibition of cell proliferation and induction of apoptosis. Moreover, SPAG9 was identified as a direct miR-874 target, the expression of which was suppressed by miR-874. SPAG9 overexpression markedly promoted GC cell proliferation.

Conclusions

miR-874 inhibited cell proliferation and induced apoptosis in GC cells. SPAG9 downregulation was crucial for the tumor-suppressive effects of miR-874. Hence, the miR-874/SPAG9 axis could serve as a novel therapeutic target in GC.

microRNA-665 is down-regulated in gastric cancer and inhibits proliferation, invasion, and EMT by targeting PPP2R2A

Recently, microRNA-665 (miR-665) has been reported to function as both tumour suppressor and oncogene in several cancer types, including gastric cancer, hepatocellular cancer, and lung cancer. However, the biological function of miR-665 and its precise mechanisms in gastric cancer (GC) have not been well clarified. The aim of this study was to study the roles of miR-665/PPP2R2A axis in GC. The levels of PPP2R2A and miR-665 were detected by quantitative PCR assay in GC tissues and cell lines. Moreover, the biological roles of miR-665 and PPP2R2A in GC cells were assessed by cell proliferation, invasion, and epithelial-mesenchymal transition (EMT). The mRNA and protein levels of PPP2R2A were determined by using quantitative PCR and Western blotting assays. Luciferase assays were used to confirm that PPP2R2A was one target of miR-665. In this study, the miR-665 level was dramatically reduced in GC tissues and cell lines, and the PPP2R2A expression was significantly enhanced. What is more, the PPP2R2A expression was negatively related to the miR-665 level in GC tissues. Furthermore, up-regulation of miR-665 obviously restrained GC cells proliferation, invasion, and EMT. We confirmed that miR-665 could directly target PPP2R2A by luciferase reporter assay. Besides, knockdown of PPP2R2A also could markedly inhibit the proliferation, invasion and EMT of GC cells. Finally, overexpression of miR-665 in GC cells partially reversed the promoted effects of PPP2R2A up-regulation. Overexpression of miR-665 restrained GC cells proliferation, invasion and EMT via regulation of PPP2R2A. SIGNIFICANCE OF THE STUDY:  miR-665 has been reported to function as oncogene or tumour suppressor in different cancers. However, the precise roles of miR-665 in GC have not been elucidated. Our study for the first time demonstrated that miR-665 level was significantly down-regulated in GC. Additionally, miR-665 overexpression inhibited cell growth, invasion, and EMT of GC. Moreover, our data suggested a significant negative correlation between miR-665 and PPP2R2A expression in GC. MiR-665 suppressed GC cell proliferation, invasion, and EMT by directly targeting PPP2R2A, which suggested important roles for miR-665/PPP2R2A axis in the GC pathogenesis and its potential application in cancer therapy.

Retracted Article: LncRNA SNHG5 regulates the cell viability and apoptosis of glioma cells by the miR-1297/KPNA2 axis

Long non-coding RNA small nucleolar RNA host gene 5 (lncRNA SNHG5) has been reported to participate in the occurrence and development of glioma. However, the function and underlying molecular mechanisms of SNHG5 in glioma remain largely unknown. The expressions of SNHG5, microRNA-1297 (miR-1297) and karyopherin subunit alpha 2 (KPNA2) in glioma tissues and cells were evaluated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) or western blot. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometry were used to detect cell viability and apoptosis, respectively. Western blot was also performed to detect the expressions of autophagy-associated proteins. The relationship among lncRNA SNHG5, miR-1297 and KPNA2 was verified by luciferase reporter assay and RNA immunoprecipitation (RIP) assay. SNHG5 and KPNA2 were over expressed, and the level of miR-1297 was down-regulated in glioma tissues and cell lines. Knockdown of SHNG5 promoted apoptosis, while suppressing cell viability and autophagy of A172 and LN340 cells. Meanwhile, SHNG5 harbored the binding sites with miR-1297, and a negative correlation between the expression of SNHG5 and miR-1297 in glioma tissues was also observed. Interestingly, silencing of miR-1297 undermined the SHNG5 depletion-mediated effect on cell viability, apoptosis, and autophagy. KPNA2 was a direct target of miR-1297, and negatively regulated by miR-1297. More importantly, gain of KPNA2 mitigated the effect of SHNG5l knockdown on glioma cells. Silencing of SNHG5 had an implication in inhibiting apoptosis and stimulating cell viability and autophagy by the miR-1297/KPNA2 axis in glioma.

Long non-coding RNA small nucleolar RNA host gene 5 (lncRNA SNHG5) has been reported to participate in the occurrence and development of glioma.