miR-363-3p induces EMT via the Wnt/β-catenin pathway in glioma cells by targeting CELF2

MicroRNA-429 overexpression overcomes imatinib resistance of glioma cells by negatively regulating lysophosphatidic acid receptor 1

BACKGROUND

Glioma is one of the most aggressive and lethal malignancies in central nervous system. It has been reported that miR-429 is declined in glioma and functions as a tumor suppressor. Nonetheless, the potential role of miR-429 in drug resistance of glioma is still ambiguous.

METHODS

Stable imatinib-resistant lines U251-AR and T98G-AR were established using glioma cell lines U251 and T98G. Cell apoptosis and cycle were analyzed by flow cytometry, and CCK-8 assay was utilized to measure cell viability. Protein and RNA levels were tested with western blot and RT-qPCR. The predicted binding site was confirmed by dual luciferase reporter assay.

RESULTS

Imatinib-resistant U251-AR and T98G-AR cells presented lower level of miR-429 and higher level of LPAR1. MiR-429 overexpression obviously promoted imatinib sensitivity in glioma cells, indicated by the reduced IC50 value, facilitated cell apoptosis and cell cycle arrest at G0/G1 phase, and downregulated multidrug resistance-related proteins. LPAR1 was verified as a direct target of miR-429 and its expression was negatively regulated by miR-429. Additionally, overexpression of LPAR1 restrained the biological function of miR-429 on imatinib chemoresistance.

CONCLUSION

MiR-429 partly sensitized glioma cells to imatinib via downregulation LPAR1, which might provide an approach to overcome imatinib chemoresistance during glioma treatment.

Role of microRNA-363 during tumor progression and invasion

Recent progresses in diagnostic and therapeutic methods have significantly improved prognosis in cancer patients. However, cancer is still considered as one of the main causes of human deaths in the world. Late diagnosis in advanced tumor stages can reduce the effectiveness of treatment methods and increase mortality rate of cancer patients. Therefore, investigating the molecular mechanisms of tumor progression can help to introduce the early diagnostic markers in these patients. MicroRNA (miRNAs) has an important role in regulation of pathophysiological cellular processes. Due to their high stability in body fluids, they are always used as the non-invasive markers in cancer patients. Since, miR-363 deregulation has been reported in a wide range of cancers, we discussed the role of miR-363 during tumor progression and metastasis. It has been reported that miR-363 has mainly a tumor suppressor function through the regulation of transcription factors, apoptosis, cell cycle, and structural proteins. MiR-363 also affected the tumor progression via regulation of various signaling pathways such as WNT, MAPK, TGF-β, NOTCH, and PI3K/AKT. Therefore, miR-363 can be introduced as a probable therapeutic target as well as a non-invasive diagnostic marker in cancer patients.

Novel cancer-fighting role of ticagrelor inhibits GTSE1-induced EMT by regulating PI3K/Akt/NF-κB signaling pathway in malignant glioma

Background

Glioma is the most common malignant brain tumor of the central nervous system. Despite of the improvement of therapeutic strategy, the prognosis of malignant glioma patients underwent by STUPP strategy is still unexpected. Previous studies have suggested that ticagrelor exerted chemotherapeutic effects by inhibition of epithelial-mesenchymal transition (EMT) in various diseases including tumors. However, whether ticagrelor can exhibit the antitumor efficiency in glioma by affecting the EMT process is still unclear. In this study, we investigated the cancer-fighting role of ticagrelor and demonstrated its chemotherapeutic mechanism in glioma.

Materials and methods

The MTT assay was performed to detect the cytotoxicity of ticagrelor in glioma cells. We evaluated the expression of Ki67 in glioma cells by immunofluorescence assay after ticagrelor treatment. We conducted wound healing assay and transwell assay to determine the effects of ticagrelor on the migration and invasion of glioma cells. RNA-seq analysis was conducted to examine potential target genes and alternative signaling pathways for ticagrelor treatment. The expression levels of key EMT -related proteins were examined by Western blot experiment.

Results

Ticagrelor inhibited the proliferation, migration and invasion of glioma cells with a favorable toxicity profile in vitro. Ticagrelor downregulated the expression of GTSE1 in glioma cells. RNA-seq analysis explored that GTSE1 acted as the potential target gene for ticagrelor treatment. Upregulation of GTSE1 antagonized the inhibitory effect of ticagrelor on the invasion of glioma and EMT progression by regulation of PI3K/Akt/NF-κB signaling pathway. And ticagrelor also exhibited the similar chemotherapeutic effect of glioma in vivo.

Conclusions

Ticagrelor as a potential chemotherapeutic option induced the inhibition of the GTSE1-induced EMT progression by regulation of PI3K/AKT/NF-κB signaling pathway.

The plasma miRNome and venous thromboembolism in high-grade glioma: miRNA Sequencing of a nested case-control cohort

Patients with high-grade gliomas are at high risk of venous thromboembolism (VTE). MicroRNAs (miRNAs) are small non-coding RNAs with multiple roles in tumour biology, haemostasis and platelet function. Their association with VTE risk in high-grade glioma has not been comprehensively mapped so far. We thus conducted a nested case-control study within 152 patients with WHO grade IV glioma that had been part of a prospective cohort study on VTE risk factors. At inclusion a single blood draw was taken, and patients were thereafter followed for a maximum of 2 years. During that time, 24 patients (16%) developed VTE. Of the other 128 patients, we randomly selected 24 age- and sex-matched controls. After quality control, the final group size was 21 patients with VTE during follow-up and 23 without VTE. Small RNA next-generation sequencing of plasma was performed. We observed that hsa-miR-451a was globally the most abundant miRNA. Notably, 51% of all miRNAs showed a correlation with platelet count. The analysis of miRNAs differentially regulated in VTE patients-with and without platelet adjustment-identified potential VTE biomarker candidates such as has-miR-221-3p. Therewith, we here provide one of the largest and deepest peripheral blood miRNA datasets of high-grade glioma patients so far, in which we identified first VTE biomarker candidates that can serve as the starting point for future research.

miRNA-363-3p Hinders Proliferation, Migration, Invasion and Autophagy of Thyroid Cancer Cells by Controlling SYT1 Transcription to affect NF-κB

BACKGROUND

Thyroid cancer (TC) is a frequent endocrine malignant tumor with various pathologic types. miRNA-363-3p plays a pivotal part in the occurrence, development, prognosis, and treatment of cancer.

OBJECTIVE

To explore the mechanism of miRNA-363-3p in TC and provide a new idea for targeted therapy of TC.

METHODS

Differential miRNAs and downstream target mRNAs in TC tissues were predicted with bioinformatics analysis. Expression levels of miRNA-363-3p and Synaptotagmin I (SYT1) in TC cells were ascertained by qRT-PCR. Cell migration, invasion, and proliferation were detected by wound healing assay, transwell assay, colony formation assay, CCK-8, and BrdU fluorescence experiment, respectively. Flow cytometry was utilized to detect the levels of apoptosis and necrosis. Immunofluorescence assay was used for detecting autophagosome formation in cells, and the expression levels of autophagy-related proteins, as well as NF-κB related proteins, were measured by western blot. Dual-luciferase reporter gene assay was applied for detecting the interaction between miRNA-363-3p and SYT1.

RESULTS

miRNA-363-3p was prominently down-regulated in TC cells. miRNA-363-3p overexpression suppressed migration, invasion, and proliferation, promoting apoptosis and necrosis of TC cells. As the downstream target of miRNA-363-3p, SYT1 was up-regulated in TC cells. SYT1 overexpression reversed the inhibition of TC cell proliferation, invasion, migration, and autophagy mediated by miRNA-363-3p overexpression. In addition, miRNA-363-3p overexpression inhibited the activation of the NF-κB pathway in cells, while further overexpression of SYT1 weakened the inhibition of miRNA-363-3p overexpression on the NF-κB pathway.

CONCLUSION

miRNA-363-3p affected the NF-κB signaling pathway by down-regulating SYT1 expression to inhibit the malignant progression of TC cells, providing theoretical support for the treatment of TC.

CELF2 Sustains a Proliferating/OLIG2+ Glioblastoma Cell Phenotype via the Epigenetic Repression of SOX3

Glioblastomas (GBs) are incurable brain tumors. The persistence of aggressive stem-like tumor cells after cytotoxic treatments compromises therapeutic efficacy, leading to GBM recurrence. Forcing the GBM cells to irreversibly abandon their aggressive stem-like phenotype may offer an alternative to conventional cytotoxic treatments. Here, we show that the RNA binding protein CELF2 is strongly expressed in mitotic and OLIG2-positive GBM cells, while it is downregulated in differentiated and non-mitotic cells by miR-199a-3p, exemplifying GBM intra-tumor heterogeneity. Using patient-derived cells and human GBM samples, we demonstrate that CELF2 plays a key role in maintaining the proliferative/OLIG2 cell phenotype with clonal and tumorigenic properties. Indeed, we show that CELF2 deficiency in patient-derived GSCs drastically reduced tumor growth in the brains of nude mice. We further show that CELF2 promotes TRIM28 and G9a expression, which drive a H3K9me3 epigenetic profile responsible for the silencing of the SOX3 gene. Thus, CELF2, which is positively correlated with OLIG2 and Ki67 expression in human GBM samples, is inversely correlated with SOX3 and miR-199a-3p. Accordingly, the invalidation of SOX3 in CELF2-deficient patient-derived cells rescued proliferation and OLIG2 expression. Finally, patients expressing SOX3 above the median level of expression tend to have a longer life expectancy. CELF2 is therefore a crucial target for the malignant potential of GBM and warrants attention when developing novel anticancer strategies.

Role of CELF2 in ferroptosis: Potential targets for cancer therapy (Review)

Ferroptosis is a novel form of regulated cellular necrosis that plays a critical role in promoting cancer progression and developing drug resistance. The main characteristic of ferroptosis is iron‑dependent lipid peroxidation caused by excess intracellular levels of reactive oxygen species. CUGBP ELAV‑like family number 2 (CELF2) is an RNA‑binding protein that is downregulated in various types of cancer and is associated with poor patient prognoses. CELF2 can directly bind mRNA to a variety of ferroptosis control factors; however, direct evidence of the regulatory role of CELF2 in ferroptosis is currently limited. The aim of the present review was to summarise the findings of previous studies on CELF2 and its role in regulating cellular redox homeostasis. The present review may provide insight into the possible mechanisms through which CELF2 affects ferroptosis and to provide recommendations for future studies.

Epigenetic regulation of temozolomide resistance in human cancers with an emphasis on brain tumors: Function of non-coding RNAs

Brain tumors, which are highly malignant, pose a significant threat to health and often result in substantial rates of mortality and morbidity worldwide. The brain cancer therapy has been challenging due to obstacles such as the BBB, which hinders effective delivery of therapeutic agents. Additionally, the emergence of drug resistance further complicates the management of brain tumors. TMZ is utilized in brain cancer removal, but resistance is a drawback. ncRNAs are implicated in various diseases, and their involvement in the cancer is particularly noteworthy. The focus of the current manuscript is to explore the involvement of ncRNAs in controlling drug resistance, specifically in the context of resistance to the chemotherapy drug TMZ. The review emphasizes the function of ncRNAs, particularly miRNAs, in modulating the growth and invasion of brain tumors, which significantly influences their response to TMZ treatment. Through their interactions with various molecular pathways, miRNAs are modulators of TMZ response. Similarly, lncRNAs also associate with molecular pathways and miRNAs, affecting the efficacy of TMZ chemotherapy. Given their functional properties, lncRNAs can either induce or suppress TMZ resistance in brain tumors. Furthermore, circRNAs, which are cancer controllers, regulate miRNAs by acting as sponges, thereby impacting the response to TMZ chemotherapy. The review explores the correlation between ncRNAs and TMZ chemotherapy, shedding light on the underlying molecular pathways involved in this process.

Non-coding RNA-based therapeutics in cancer therapy: An emphasis on Wnt/β-catenin control

Non-coding RNA transcripts are RNA molecules that have mainly regulatory functions and they do not encode proteins. microRNAs (miRNAs), lncRNAs and circRNAs are major types of this family and these epigenetic factors participate in disease pathogenesis, especially cancer that their abnormal expression may lead to cancer progression. miRNAs and lncRNAs possess a linear structure, whereas circRNAs possess ring structures and high stability. Wnt/β-catenin is an important factor in cancer with oncogenic function and it can increase growth, invasion and therapy resistance in tumors. Wnt upregulation occurs upon transfer of β-catenin to nucleus. Interaction of ncRNAs with Wnt/β-catenin signaling can determine tumorigenesis. Wnt upregulation is observed in cancers and miRNAs are able to bind to 3'-UTR of Wnt to reduce its level. LncRNAs can directly/indirectly regulate Wnt and in indirect manner, lncRNAs sponge miRNAs. CircRNAs are new emerging regulators of Wnt and by its stimulation, they increase tumor progression. CircRNA/miRNA axis can affect Wnt and carcinogenesis. Overall, interaction of ncRNAs with Wnt can determine proliferation rate, migration ability and therapy response of cancers. Furthermore, ncRNA/Wnt/β-catenin axis can be utilized as biomarker in cancer and for prognostic applications in patients.

Circ_0002111 modulates the growth process of papillary thyroid carcinoma cells by targeting the miR-363-3p/HMGB1 axis

Previous studies have suggested that circular RNAs (circRNAs) are engaged in the progression of papillary thyroid carcinoma (PTC). However, the mechanism of circ_0002111 in PTC is still unclear. In this study, quantitative real-time PCR was carried out to measure the expressions of circ_0002111, microRNAs (miRNAs) and high-mobility group box 1 (HMGB1). Immunohistochemistry assay and western blot were applied for the determination of protein levels. The assays of 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide and thymidine analog 5-ethynyl-2'-deoxyuridine were deployed to assess PTC cell viability and proliferation, respectively. Besides, the capacities of cell apoptosis, invasion and angiogenesis were determined by flow cytometry, transwell and tube formation assays, respectively. Moreover, the interaction between miR-363-3p and circ_0002111 or HMGB1 was confirmed using a dual-luciferase reporter assay. Lastly, we established a xenograft model for the examination of the function of circ_0002111 in vivo. It was found that the expression of circ_0002111 was enhanced in PTC tissues and cells. Silencing circ_0002111 apparently retarded the viability, proliferation, invasion and tube formation, as well as expedited the apoptosis of PTC cells. Besides, circ_0002111 knockdown impeded the growth of the tumor in vivo. For mechanism analysis, circ_0002111 adjusted the expression of HMGB1 by sponge adsorption of miR-363-3p. Moreover, miR-363-3p inhibitor regained the influence of cellular malignant phenotype caused by circ_0002111 knockdown. Additionally, miR-363-3p overexpression impacted the cell functions by targeting HMGB1 in PTC. Thus, silencing circ_0002111 constrained the progression of PTC by the miR-363-3p/HMGB1 axis, which perhaps provided a novel idea of the therapeutic in PTC.

MicroRNAs, Key Regulators in Glioma Progression as Potential Therapeutic Targets for Chinese Medicine

Gliomas are tumors of the primary central nervous system associated with poor prognosis and high mortality. The 5-year survival rate of patients with gliomas received surgery combined with chemotherapy or radiotherapy does not exceed 5%. Although temozolomide is commonly used in the treatment of gliomas, the development of resistance limits its use. MicroRNAs are non-coding RNAs involved in numerous processes of glioma cells, such as proliferation, migration and apoptosis. MicroRNAs regulate cell cycle, PI3K/AKT signal pathway, and target apoptosis-related genes (e.g., BCL6), angiogenesis-related genes (e.g., VEGF) and other related genes to suppress gliomas. Evidence illustrates that microRNAs can regulate the sensitivity of gliomas to temozolomide, cisplatin, and carmustine, thereby enhancing the efficacy of these agents. Moreover, traditional Chinese medicine (e.g., tanshinone IIA, xanthohumol, and curcumin) exert antiglioma effects by regulating the expression of microRNAs, and then microRNAs inhibit gliomas through influencing the process of tumors by targeting certain genes. In this paper, the mechanisms through which microRNAs regulate the sensitivity of gliomas to therapeutic drugs are described, and traditional Chinese medicine that can suppress gliomas through microRNAs are discussed. This review aims to provide new insights into the traditional Chinese medicine treatment of gliomas.

EMX1 functions as a tumor inhibitor in spinal cord glioma through transcriptional suppression of WASF2 and inactivation of the Wnt/β-catenin axis

BACKGROUND

Gliomas are the most frequent and aggressive cancers in the central nervous system, and spinal cord glioma (SCG) is a rare class of the gliomas. Empty spiracles homobox genes (EMXs) have shown potential tumor suppressing roles in glioma, but the biological function of EMX1 in SCG is unclear.

METHODS

The EMX1 expression in clinical tissues of patients with SCG was examined. SCG cells were extracted from the tissues, and altered expression of EMX1 was then introduced to examine the role of EMX1 in cell growth and invasiveness in vitro. Xenograft tumors were induced in nude mice for in vivo validation. The targets of EXM1 were predicted via bioinformatic analysis and validated by luciferase and ChIP-qPCR assays. Rescue experiments were conducted to validate the involvements of the downstream molecules.

RESULTS

EMX1 was poorly expressed in glioma, which was linked to decreased survival rate of patients according to the bioinformatics prediction. In clinical tissues, EMX1 was poorly expressed in SCG, especially in the high-grade tissues. EMX1 upregulation significantly suppressed growth and metastasis of SCG cells in vitro and in vivo. EMX1 bound to the promoter of WASP family member 2 (WASF2) to suppress its transcription. Restoration of WASF2 blocked the tumor-suppressing effect of EMX1. EMX1 suppressed Wnt/β-catenin signaling activity by inhibiting WASF2. Coronaridine, a Wnt/β-catenin-specific antagonist, blocked SCG cell growth and metastasis induced by WASF2.

CONCLUSION

This study elucidates that EMX1 functions as a tumor inhibitor in SCG by suppressing WASF2-dependent activation of the Wnt/β-catenin axis.

miR-363-3p induces EMT via the Wnt/β-catenin pathway in glioma cells by targeting CELF2

In our previous study, we reported that CELF2 has a tumour‐suppressive function in glioma. Here, we performed additional experiments to elucidate better its role in cancer. The expression profile of CELF2 was analysed by the GEPIA database, and Kaplan–Meier curves were used to evaluate the overall survival rates. Four different online databases were used to predict miRNAs targeting CELF2, and the luciferase assay was performed to identify the binding site. The biological effects of miR‐363‐3p and CELF2 were also investigated in vitro using MTT, Transwell, and flow cytometry assays. Western blotting, qPCR, and TOP/FOP flash dual‐luciferase assays were performed to investigate the impact of miR‐363‐3p and CELF2 on epithelial‐to‐mesenchymal transition (EMT) and the Wnt/β‐catenin pathway. The effect of miR‐363‐3p was also tested in vivo using a xenograft mouse model. We observed an abnormal expression pattern of CELF2 in glioma cells, and higher CELF2 expression correlated with better prognosis. We identified miR‐363‐3p as an upstream regulator of CELF2 and confirmed its direct binding to the 3′‐untranslated region of CELF2. Cell function experiments showed that miR‐363‐3p affected multiple aspects of glioma cells. Suppressing miR‐363‐3p expression inhibited glioma cell proliferation and invasion, as well as promoted cell death via attenuating EMT and blocking the Wnt/β‐catenin pathway. These effects could be abolished by the downregulation of CELF2. Treatment with ASO‐miR‐363‐3p decreased tumour size and weight in nude mice. In conclusion, miR‐363‐3p induced the EMT, which resulted in increased migration and invasion and reduced apoptosis in glioma cell lines, via the Wnt/β‐catenin pathway by targeting CELF2.