Circ-PVT1/miR-106a-5p/HK2 axis regulates cell growth, metastasis and glycolytic metabolism of oral squamous cell carcinoma

Circular RNA as a Biomarker for Diagnosis, Prognosis and Therapeutic Target in Acute and Chronic Lymphoid Leukemia

Circular RNAs (circRNAs) are single-stranded RNAs that have received much attention in recent years. CircRNAs lack a 5' head and a 3' poly-A tail. The structure of this type of RNAs make them resistant to digestion by exonucleases. CircRNAs are expressed in different cells and have various functions. The function of circRNAs is done by sponging miRNAs, changing gene expression, and protein production. The expression of circRNAs changes in different types of cancers, which causes changes in cell growth, proliferation, differentiation, and apoptosis. Changes in the expression of circRNAs can cause the invasion and progression of tumors. Studies have shown that changes in the expression of circRNAs can be seen in acute lymphoid leukemia (ALL) and chronic lymphoid leukemia (CLL). The conducted studies aim to identify circRNAs whose expression has changed in these leukemias and their more precise function so that these circRNAs can be identified as biomarkers, prediction of patient prognosis, and treatment targets for ALL and CLL patients. In this study, we review the studies conducted on the role and function of circRNAs in ALL and CLL patients. The results of the studies show that there is a possibility of using circRNAs as biomarkers in the identification and treatment of patients in the future.

Connecting the dots: investigating the link between environmental, genetic, and epigenetic influences in metabolomic alterations in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) accounts for around 90% of all oral cancers and is the eighth most common cancer worldwide. Despite progress in managing OSCC, the overall prognosis remains poor, with a survival rate of around 50-60%, largely due to tumor size and recurrence. The challenges of late-stage diagnosis and limitations in current methods emphasize the urgent need for less invasive techniques to enable early detection and treatment, crucial for improving outcomes in this aggressive form of oral cancer. Research is currently aimed at unraveling tumor-specific metabolite profiles to identify candidate biomarkers as well as discover underlying pathways involved in the onset and progression of cancer that could be used as new targets for diagnostic and therapeutic purposes. Metabolomics is an advanced technological approach to identify metabolites in different sample types (biological fluids and tissues). Since OSCC promotes metabolic reprogramming influenced by a combination of genetic predisposition and environmental factors, including tobacco and alcohol consumption, and viral infections, the identification of distinct metabolites through screening may aid in the diagnosis of this condition. Moreover, studies have shown the use of metabolites during the catalysis of epigenetic modification, indicating a link between epigenetics and metabolism. In this review, we will focus on the link between environmental, genetic, and epigenetic influences in metabolomic alterations in OSCC. In addition, we will discuss therapeutic targets of tumor metabolism, which may prevent oral tumor growth, metastasis, and drug resistance.

The effect and mechanism of hexokinase-2 on cisplatin resistance in lung cancer cells A549

BACKGROUND

Hexokinase (HK) is the first rate-limiting enzyme of glycolysis, which can convert glucose to glucose-6-phosphate. There are several subtypes of HK, including HK2, which is highly expressed in a variety of different tumors and is closely associated with survival.

METHODS

Non-small cell lung cancer (NSCLC) A549 cells with stable overexpression and knockdown of HK2 were obtained by lentivirus transfection. The effects of overexpression and knockdown of HK2 on proliferation, migration, invasion, and glycolytic activity of A549 cells were investigated. The effects on apoptosis were also analyzed using western blot and flow cytometry. In addition, the mitochondria and cytoplasm were separated and the expression of apoptotic proteins was detected by western blot respectively.

RESULTS

Upregulation of HK2 could promote glycolysis, cell proliferation, migration, and invasion, which would be inhibited through the knockdown of HK2. HK2 overexpression contributed to cisplatin resistance, whereas HK2 knockdown enhanced cisplatin-induced apoptosis in A549 cells.

CONCLUSIONS

Overexpression of HK2 can promote the proliferation, migration, invasion, and drug resistance of A549 cells by enhancing aerobic glycolysis and inhibiting apoptosis. Reducing HK2 expression or inhibiting HK2 activity can inhibit glycolysis and induce apoptosis in A549 cells, which is expected to be a potential treatment method for NSCLC.

AKR1B10 accelerates glycolysis through binding HK2 to promote the malignant progression of oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) remains a rampant oral cavity neoplasm with high degree of aggressiveness. Aldo-keto reductase 1B10 (AKR1B10) that is an oxidoreductase dependent on nicotinamide adenine dinucleotide phosphate (NADPH) has been introduced to possess prognostic potential in OSCC. The present work was focused on specifying the involvement of AKR1B10 in the process of OSCC and its latent functional mechanism.

METHODS

AKR1B10 expression in OSCC tissues and cells were detected by RT-qPCR and Western blot analysis. CCK-8 method, EdU staining, wound healing and transwell assays respectively assayed cell viability, proliferation, migration and invasion. Immunofluorescence staining and Western blot evaluated epithelial mesenchymal transition (EMT). Adenosine triphosphate (ATP) contents, glucose consumption and extracellular acidification rate (ECAR) were measured by relevant commercially available kits and Seahorse XF96 Glycolysis Analyzer, severally. The expressions of proteins associated with metastasis and glycolysis were examined with Western blot. Co-IP assay confirmed the binding between AKR1B10 and hexokinase 2 (HK2).

RESULTS

It was observed that AKR1B10 expression was increased in OSCC tissues and cells. After AKR1B10 was knocked down, the proliferation, migration, invasion and EMT of OSCC cells were all hampered. Additionally, AKR1B10 silencing suppressed glycolysis and bound to HK2 in OSCC cells. Up-regulation of HK2 partially abolished the hampered glycolysis, proliferation, migration, invasion and EMT of AKR1B10-silenced OSCC cells.

CONCLUSION

To sum up, AKR1B10 could bind to HK2 to accelerate glycolysis, thereby facilitating the proliferation, migration, invasion and EMT of OSCC cells.

Long Non-coding RNA Prader Willi/Angelman Region RNA 6 Suppresses Glioma Development by Modulating MicroRNA-106a-5p

As one of the most frequent intracranial tumors, glioma showed invasive development and poor prognosis. lncRNAs have been illustrated to serve as biomarkers in various cancers. Whether the long non-coding RNA Prader Willi/Angelman region RNA 6 (PWAR6) was involved in glioma development and the underlying mechanism was investigated. PWAR6 in glioma was evaluated by polymerase chain reaction and its clinical significance was assessed with a series of statistical analyses. The biological function of PWAR6 was investigated with the cell counting kit 8 and Transwell assay. The potential underlying mechanism was studied with the luciferase reporter assay. The significant downregulation of PWAR6 was observed in glioma, which showed a close relationship with the major clinicopathological features and poor prognosis of patients. PWAR6 restrained cell growth, migration and invasion of glioma, which was alleviated by the overexpression of microRNA-106a-5p (miR-106a-5p). PWAR6 functioned as a prognostic biomarker and tumor suppressor of glioma through regulating miR-106a-5p.

CircRNA ITCH Inhibits Epithelial-Mesenchymal Transformation and Promotes Apoptosis in Papillary Thyroid Carcinoma via miR-106a-5p/JAZF1 Axis

Circular RNA ITCH (circ-ITCH) is implicated in papillary thyroid carcinoma (PTC) development. Nevertheless, the more detailed molecular mechanism remains uncovered. The transcriptional level of circ-ITCH was tested via quantitative real-time PCR. Transwell assay was introduced to assess the migrative and invasive abilities of cells. RNA interference technology was employed to reduce the level of circ-ITCH as well as JAZF1 in PTC cells. Western blot assay was utilized to reveal the content of JAZF1 and proteins related to epithelial-mesenchymal transformation (EMT) progression. Circ-ITCH was downregulated in PTC tissues as well as cells. Overexpression of circ-ITCH suppressed EMT, migration, invasion, facilitated apoptosis in PTC cells, while silencing circ-ITCH exhibited reversed effects. Additionally, miR-106a-5p was the target of circ-ITCH and negatively regulated through circ-ITCH. MiR-106a-5p mimic partly eliminated the influences of overexpressed circ-ITCH in PTC cells. Moreover, JAZF1 could interact with miR-106a-5p, then it was regulated via circ-ITCH. Silencing JAZF1 partially counteracted the role of circ-ITCH in PTC cells progress. This study uncovered that circ-ITCH suppressed the development of PTC cells at least partly by mediating miR-106a-5p/JAZF1 network.

Sevoflurane inhibits oral squamous carcinoma progression by modulating the circ_0000857/miR-145-5p axis

Oral squamous cell carcinoma (OSCC) is a kind of oral malignant tumor with the highest incidence. This study investigated whether sevoflurane (SEV) inhibited OSCC cell progression by regulating circular RNA_0000857 (circ_0000857). OSCC cells were anesthetized with SEV at different concentrations. The expression of circ_0000857 and microRNA-145-5p (miR-145-5p) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability was assayed by the Cell Counting Kit-8 (CCK-8), and cell migration and invasion were examined by the wound-healing assay and transwell. Tube formation assay detected angiogenesis. Western blot was used to detect the expression of related proteins. Compared with the control group, SEV inhibited OSCC cell migration, invasion, and angiogenesis. SEV treatment significantly decreased circ_0000857 expression level, but increased miR-145-5p expression level in SCC4 and HSC3 cells. MiR-145-5p was a target of circ_0000857, and miR-145-5p inhibitor reversed the suppressing effects mediated by circ_0000857 silencing on OSCC cell migration, invasion, and angiogenesis. SEV inhibited the level of matrix metalloproteinases 2 (MMP2), MMP9, and vascular endothelial growth factor A (VEGFA) protein by regulating the circ_0000857/miR-145-5p axis. In all, SEV regulated the migration, invasion, and angiogenesis of OSCC cells through the circ_0000857/miR-145-5p axis, which provided a basis for the potential role of SEV in the treatment of OSCC.

A snapshot of miRNAs in oral squamous cell carcinoma: Difference between cancer cells and corresponding normal cells

Oral squamous cell carcinoma (OSCC) constitutes the most aggressive tumors of the oral cavity and is one of the leading causes of cancer mortality worldwide. Although recent clinical treatment strategies have improved the survival rate, the outcome of OSCC patients still remains dismal because of the lack of efficient diagnostic and treatment tools. As one of the main actors of OSCC scenario, microRNAs (miRNAs) are involved in triggering, progression and metastasis through the regulation of various cancer-related signaling pathways. Identification followed by precise study of the biology and mechanism of action of miRNAs will greatly help to provide valuable insights regarding OSCC development and can be considered as an anti-OSCC target. In the current review, we have provided a focused summary of the latest published papers on the role of miRNAs in apoptosis, cell cycle, proliferation, EMT and metastasis of OSCC as well as the role of long noncoding RNAs in the modulation of miRNAs in OSCC.

The role and mechanism of circ-BNC2 on the malignant progression of oral squamous cell carcinoma

BACKGROUND

Circular RNAs (circRNAs) play a key part in the progression of oral squamous cell carcinoma (OSCC). However, the role of circ-BNC2 (circRNA ID hsa_circ_0086414) in OSCC progression is still unclear.

METHODS

Plasmid transfection was used to induce overexpression of circ-BNC2. RNA expression of circ-BNC2, microRNA-142-3p (miR-142-3p) and GNAS complex locus (GNAS) was detected by quantitative real-time polymerase chain reaction. Protein expression was assessed by western blot assay or immunohistochemistry assay. Cell proliferation was investigated by 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, colony formation assay and flow cytometry analysis. Cell migratory and invasive abilities and cell apoptosis were assessed by transwell assay and flow cytometry analysis, respectively. Oxidative stress was evaluated by superoxide dismutase activity detection assay, lipid peroxidation malondialdehyde assay and cellular reactive oxygen species assay. The binding relationship between miR-142-3p and circ-BNC2 or GNAS was proved by dual-luciferase reporter assay and RNA immunoprecipitation assay. The impacts of circ-BNC2 overexpression on tumor growth in vivo were unveiled by a xenograft mouse model assay.

RESULTS

Circ-BNC2 expression was downregulated in OSCC tissues and cells when compared with adjacent healthy tissues and normal human oral keratinocytes. Circ-BNC2 overexpression repressed the proliferation, migration and invasion of OSCC cells but induced cell apoptosis and oxidative stress. Additionally, circ-BNC2 overexpression inhibited tumor growth in vivo. Furthermore, circ-BNC2 bound to miR-142-3p, and miR-142-3p targeted GNAS. MiR-142-3p mimic attenuated circ-BNC2 overexpression-mediated effects on the proliferation, migration, invasion, apoptosis and oxidative stress of OSCC cells. The regulation of miR-142-3p in OSCC cell tumor properties involved GNAS. Further, circ-BNC2 introduction promoted GNAS expression by inhibiting miR-142-3p.

CONCLUSION

Circ-BNC2 suppressed OSCC malignant progression by upregulating GNAS expression in a miR-142-3p-dependent manner, which suggested that circ-BNC2 might be a novel target for OSCC therapy.

RNA-Based Liquid Biopsy in Head and Neck Cancer

Head and neck cancer (HNC) is a prevalent and diverse group of malignancies with substantial morbidity and mortality rates. Early detection and monitoring of HNC are crucial for improving patient outcomes. Liquid biopsy, a non-invasive diagnostic approach, has emerged as a promising tool for cancer detection and monitoring. In this article, we review the application of RNA-based liquid biopsy in HNC. Various types of RNA, including messenger RNA (mRNA), microRNA (miRNA), long non-coding RNA (lncRNA), small nuclear RNA (snRNA), small nucleolar RNA (snoRNA), circular RNA (circRNA) and PIWI-interacting RNA (piRNA), are explored as potential biomarkers in HNC liquid-based diagnostics. The roles of RNAs in HNC diagnosis, metastasis, tumor resistance to radio and chemotherapy, and overall prognosis are discussed. RNA-based liquid biopsy holds great promise for the early detection, prognosis, and personalized treatment of HNC. Further research and validation are necessary to translate these findings into clinical practice and improve patient outcomes.

Circ_0004491 stimulates guanine nucleotide-binding protein alpha subunit to inhibit the malignant progression of oral squamous cell carcinoma by sponging miR-2278

Background/purpose

Circular RNA origin recognition complex subunit 4 (circORC4; ID: hsa_circ_0004491) have been confirmed to be a novel potential biomarker of oral squamous cell carcinoma (OSCC). This study aimed to explore the molecular mechanism of circ_0004491 in OSCC progression.

Materials and methods

Levels of circ_0004491, microRNA (miR)-2278, guanine nucleotide-binding protein alpha subunit (GNAS), Bax, Bcl-2, E-cadherin and ki-67 were detected by quantitative real-time PCR, western blotting and immunohistochemistry. The proliferation of OSCC cells was measured using colony formation assay and EdU staining. Cell apoptosis and motility were detected by flow cytometry and transwell assays respectively. Interaction between miR-2278 and circ_0004491 or GNAS was predicted by bioinformatics analysis and confirmed via luciferase reporter assay and RNA immunoprecipitation assay. Xenograft tumor model was used to analyze the role of circ_0004491 in tumor growth in vivo.

Results

Circ_0004491 was downregulated in OSCC tissues and cell lines. Circ_0004491 overexpression suppressed the proliferation, migration and invasion whereas facilitated the apoptosis of OSCC cells. Circ_0004491 acted as a molecular sponge for miR-2278, and circ_0004491 overexpression-mediated effect was partly reversed by miR-2278 mimic in OSCC cells. MiR-2278 interacted with the 3'UTR of GNAS. Circ_0004491 contributed to GNAS level by sponging miR-2278 in OSCC cells. GNAS knockdown restored miR-2278 inhibitor-mediated effect in OSCC cells. Circ_0004491 overexpression repressed xenograft tumor growth in vivo.

Conclusion

Circ_0004491 can repress OSCC progression by regulation of miR-2278/GNAS axis, providing a possible circRNA-targeted therapy for OSCC.

Hsa_circ_0005050 regulated the progression of oral squamous cell carcinoma via miR-487a-3p/CHSY1 axis

Background/purpose

Circular RNAs (circRNAs) have been identified as potential functional modulators of the cellular physiology processes. This study aims to learn the potential molecular mechanisms of hsa_circ_0005050 (circ_0005050) in oral squamous cell carcinoma (OSCC).

Materials and methods

Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was used to examine the expression of circ_0005050, miR-487a-3p, and chondroitin sulfate synthase 1 (CHSY1). Dual-luciferase reporter system, RNA pull-down, and RNA Immunoprecipitation (RIP) assays were used to determine the binding between miR-487a-3p and circ_0005050 or CHSY1. Colony formation experiment and EdU assay were used to investigate proliferation. Wound-healing and transwell assays were used to detect the migration of cells. The apoptosis rate of OSCC cells was tested by flow cytometry. Protein levels of related factors were determined by Western blot. Tumor xenograft was established to determine the regulatory role of circ_0005050 on tumor growth in vivo, and Ki-67 expression was detected in this xenograft using Immunohistochemical (IHC).

Results

We implicated that circ_0005050 was apparently upregulated in OSCC tissues cells. In function experiments, repressing of circ_0005050 remarkably retarded OSCC growth in vitro. Furthermore, we conducted dual-luciferase reporter assays and RNA pull-down assays to verify that circ_0005050 sponged miR-487a-3p. Suppression of miR-487a-3p rescued the inhibition of proliferation in SCC15 and SCC25 cells induced by circ_0005050 knockdown. In addition, we found that overexpression of CHSY1 also reversed the inhibitory effect of circ_0005050 silencing on cell proliferation. Moreover, circ_0005050 knockdown inhibited tumor growth in vivo.

Conclusion

Circ_0005050 acted as an oncogenic factor in OSCC progression through miR-487a-3p/CHSY1 axis.

Noncoding RNA PVT1 in osteosarcoma: The roles of lncRNA PVT1 and circPVT1

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and teenagers and is characterized by high malignant potential, rapid disease progression and high disability and mortality rates. Recently, noncoding RNAs (ncRNAs) have attracted the attention of many scholars due to their major regulatory roles in gene expression. Among them, lncRNA PVT1 and circPVT1 encoded by the PVT1 gene have been the focus of many studies; they are upregulated in OS, and abundant evidence indicates that lncRNA PVT1 and circPVT1 play key roles in the occurrence and development of OS. This review summarizes the mechanisms of action of lncRNA PVT1 and circPVT1 in regulating apoptosis, proliferation, glycolysis, invasion, migration and epithelial–mesenchymal transition (EMT) in OS and discusses their clinical applications in diagnosis, prognosis determination and drug resistance treatment, with the aim of helping researchers better understand the regulatory roles of lncRNA PVT1 and circPVT1 in OS progression and providing a theoretical basis for the development of early screening and accurate targeted treatment strategies and prognostic biomarkers for OS based on lncRNA PVT1 and circPVT1.

The expression of Hexokinase 2 and its hub genes are correlated with the prognosis in glioma

BACKGROUND

Hexokinase 2 (HK2) is an enzyme that catalyses the conversion of glucose to glucose-6-phosphate, which has been found to be associated with malignant tumour growth. However, the potential immunological and clinical significance of HK2, especially in terms of prognostic prediction for patients with glioma, has not been fully elucidated.

METHODS

To investigate the expression, immunological and clinical significance of HK2 in patients with glioma, several databases, including ONCOMINE, TIMER2.0, GEPIA, CGGA, UCSC, LinkedOmics, Metascape, STRING, GSCA, and TISIDB, as well as biochemical, cellular, and pathological analyses, were used in this study. In addition, we performed univariate, multivariate Cox regression and nomogram analyses of the hub genes positively and negatively correlated with HK2 to explore the potential regulatory mechanism in the initiation and development of glioma.

RESULTS

Our results demonstrated that HK2 was highly expressed in most malignant cancers. HK2 expression was significantly higher in lower grade glioma (LGG) and glioblastoma (GBM) than in adjacent normal tissue. In addition, HK2 expression was significantly correlated with clinical parameters, histological manifestations, and prognosis in glioma patients. Specifically, the data from The Cancer Genome Atlas downloaded from UCSC Xena database analysis showed that high expression of HK2 was strongly associated with poor prognosis in glioma patients. The LinkedOmics database indicated that HK2-related genes were mainly enriched in immune-related cells. In LGG and GBM tissues, HK2 expression is usually correlated with recognized immune checkpoints and the abundance of multiple immune infiltrates. Similarly, the Metascape database revealed that HK2-related genes were mainly enriched and annotated in immune-related pathways and immune cells. Further investigations also confirmed that the inhibition of HK2 expression remarkably suppressed metastasis and vasculogenic mimicry (VM) formation in glioma cells through regulating the gene expression of inflammatory and immune modulators.

CONCLUSION

HK2 expression was closely associated with the malignant properties of glioma through activating multiple immune-related signalling pathways to regulate immune responses and the infiltration of immune cells. Thus, HK2 and its hub genes may be a potential target for the treatment of glioma.

Circular RNA circLDLR facilitates cancer progression by altering the miR-30a-3p/SOAT1 axis in colorectal cancer

Colorectal cancer (CRC) is the third most common malignancy worldwide. Circular RNAs (circRNAs) have been reported to play critical regulatory roles in tumorigenesis, serving as tumor biomarkers and therapeutic targets. However, the contributions of circRNAs to CRC tumorigenesis are unclear. In our study, high expression of circLDLR was found in CRC tissues and cells and was closely associated with the malignant progression and poor prognosis of CRC patients. We demonstrated that circLDLR boosts growth and metastasis of CRC cells in vitro and in vivo, and modulates cholesterol levels in vitro. Mechanistically, we showed that circLDLR competitively binds to miR-30a-3p and prevents it from reducing the SOAT1 level, facilitating the malignant progression of CRC. In sum, our findings illustrate that circLDLR participates in CRC tumorigenesis and metastasis via the miR-30a-3p/SOAT1 axis, serving as a potential biomarker and therapeutic target in CRC.

Targeting Ferroptosis Pathway to Combat Therapy Resistance and Metastasis of Cancer

Ferroptosis is an iron-dependent regulated form of cell death caused by excessive lipid peroxidation. This form of cell death differed from known forms of cell death in morphological and biochemical features such as apoptosis, necrosis, and autophagy. Cancer cells require higher levels of iron to survive, which makes them highly susceptible to ferroptosis. Therefore, it was found to be closely related to the progression, treatment response, and metastasis of various cancer types. Numerous studies have found that the ferroptosis pathway is closely related to drug resistance and metastasis of cancer. Some cancer cells reduce their susceptibility to ferroptosis by downregulating the ferroptosis pathway, resulting in resistance to anticancer therapy. Induction of ferroptosis restores the sensitivity of drug-resistant cancer cells to standard treatments. Cancer cells that are resistant to conventional therapies or have a high propensity to metastasize might be particularly susceptible to ferroptosis. Some biological processes and cellular components, such as epithelial–mesenchymal transition (EMT) and noncoding RNAs, can influence cancer metastasis by regulating ferroptosis. Therefore, targeting ferroptosis may help suppress cancer metastasis. Those progresses revealed the importance of ferroptosis in cancer, In order to provide the detailed molecular mechanisms of ferroptosis in regulating therapy resistance and metastasis and strategies to overcome these barriers are not fully understood, we described the key molecular mechanisms of ferroptosis and its interaction with signaling pathways related to therapy resistance and metastasis. Furthermore, we summarized strategies for reversing resistance to targeted therapy, chemotherapy, radiotherapy, and immunotherapy and inhibiting cancer metastasis by modulating ferroptosis. Understanding the comprehensive regulatory mechanisms and signaling pathways of ferroptosis in cancer can provide new insights to enhance the efficacy of anticancer drugs, overcome drug resistance, and inhibit cancer metastasis.

Unravelling similarities and differences in the role of circular and linear PVT1 in cancer and human disease

The plasmacytoma variant translocation 1 (PVT1) is a long non-coding RNA gene involved in human disease, mainly in cancer onset/progression. Although widely analysed, its biological roles need to be further clarified. Notably, functional studies on PVT1 are complicated by the occurrence of multiple transcript variants, linear and circular, which generate technical issues in the experimental procedures used to evaluate its impact on human disease. Among the many PVT1 transcripts, the linear PVT1 (lncPVT1) and the circular hsa_circ_0001821 (circPVT1) are frequently reported to perform similar pathologic and pro-tumorigenic functions when overexpressed. The stimulation of cell proliferation, invasion and drug resistance, cell metabolism regulation, and apoptosis inhibition is controlled through multiple targets, including MYC, p21, STAT3, vimentin, cadherins, the PI3K/AKT, HK2, BCL2, and CASP3. However, some of this evidence may originate from an incorrect evaluation of these transcripts as two separate molecules, as they share the lncPVT1 exon-2 sequence. We here summarise lncPVT1/circPVT1 functions by mainly focusing on shared pathways, pointing out the potential bias that may exist when the biological role of each transcript is analysed. These considerations may improve the knowledge about lncPVT1/circPVT1 and their specific targets, which deserve further studies due to their diagnostic, prognostic, and therapeutic potential.

Identification of Metabolism-Associated Biomarkers for Early and Precise Diagnosis of Oral Squamous Cell Carcinoma

The 5-year survival rate for oral squamous cell carcinoma (OSCC), one of the most common head and neck cancers, has not improved in the last 20 years. Poor prognosis of OSCC is the result of failure in early and precise diagnosis. Metabolic reprogramming, including the alteration of the uptake and utilisation of glucose, amino acids and lipids, is an important feature of OSCC and can be used to identify its biomarkers for early and precise diagnosis. In this review, we summarise how recent findings of rewired metabolic networks in OSCC have facilitated early and precise diagnosis of OSCC.

Circ_0006948 Contributes to Cell Growth, Migration, Invasion and Epithelial-Mesenchymal Transition in Esophageal Carcinoma

BACKGROUND

Circular RNAs (circRNAs) can act as promoters or inhibitors in cancer progression. Has_circ_0006948 (circ_0006948) was reported to aggravate the malignant behaviors of esophageal carcinoma (EC).

AIMS

This study focused on investigating the molecular mechanism of circ_0006948 in EC progression.

METHODS

The quantitative real-time polymerase chain reaction was performed to detect the expression of circ_0006948, microRNA-4262 (miR-4262) and fibronectin type III domain containing 3B (FNDC3B). Cell growth analysis was conducted by Cell Counting Kit-8 and colony formation assays. Cell migration and invasion were assessed by transwell assay. Epithelial-mesenchymal transition (EMT)-associated proteins and FNDC3B protein expression were assayed using western blot. Dual-luciferase reporter and RNA pull-down assays were performed to validate the target combination. Xenograft tumor assay was used for investigating the role of circ_0006948 in vivo.

RESULTS

Circ_0006948 was upregulated in EC tissues and cells. Downregulating the expression of circ_0006948 or FNDC3B repressed cell growth, migration, invasion and EMT in EC cells. Target analysis indicated that miR-4262 was a target for circ_0006948 and FNDC3B was a downstream gene for miR-4262. Moreover, circ_0006948 could affect the expression of FNDC3B via sponging miR-4262. The effects of si-circ_0006948#1 on EC cells were partly restored by miR-4262 inhibition or FNDC3B overexpression. In addition, circ_0006948 also facilitated EC tumorigenesis in vivo by targeting the miR-4262/FNDC3B axis.

CONCLUSION

Taken together, circ_0006948 functioned as an oncogenic factor in EC by the miR-4262-mediated FNDC3B expression regulation.

CircPVT1: a pivotal circular node intersecting Long Non-Coding-PVT1 and c-MYC oncogenic signals

The role of circular RNAs in oncogenesis has begun to be widely studied in recent years, due to the significant impact that these molecules have in disease pathogenesis, as well as their potential for the future of innovative therapies. Moreover, due to their characteristically circular shape, circular RNAs are very resistant molecules to RNA degradation whose levels are easily assessed in body fluids. Accordingly, they represent an opportunity for the discovery of new diagnostic and prognostic markers in a wide range of diseases. Among circular RNAs, circPVT1 is a rather peculiar one that originates from the circularization of the exon 2 of the PVT1 gene that encodes a pro-tumorigenic long non-coding RNA named lncPVT1. There are a few examples of circular RNAs that derive from a locus producing another non-coding RNA. Despite their apparent transcriptional independence, which occurs using two different promoters, a possible synergistic effect in tumorigenesis cannot be excluded considering that both have been reported to correlate with the oncogenic phenotype. This complex mechanism of regulation appears to also be controlled by c-MYC. Indeed, the PVT1 locus is located only 53 Kb downstream c-MYC gene, a well-known oncogene that regulates the expression levels of about 15% of all genes. Here, we review circPVT1 origin and biogenesis highlighting the most important mechanisms through which it plays a fundamental role in oncogenesis, such as the well-known sponge activity on microRNAs, as well as its paradigmatic interactome link with lncPVT1 and c-MYC expression.

Circ_LPAR3 promotes the progression of oral squamous cell carcinoma (OSCC)

BACKGROUND

circ_LPAR3 is an oncogene in esophageal squamous cell carcinoma. However, its role in oral squamous cell carcinoma (OSCC) is unknown.

PURPOSE

To reveal the functions of circ_LPAR3 in OSCC.

METHODS

Online bioinformatic analysis was performed to disclose the differential expression of circ_LPAR3, VEGFC, AKT1 in OSCC and also the target predictions of miR-513b-5p. Transfection was applied in OSCC cells. RT-qPCR was used to detect the RNA expression and western blot to measure the proteins, VEGFC and phosphor-AKT1 (ser473, p-AKT1). CCK8 kit was used for viability detection and Flow cytometry for apoptosis evaluation. RNA pull-down and luciferase reporter methods were used to validate the binding sites to miR-513b-5p on circ_LPAR3, VEGFC and AKT1. OSCC mice models were established to further unveil the functions of circ_LPAR3 in OSCC in vivo. H&E staining and immunohistochemistry (CD34, VEGFC and p-AKT1) were further applied to analyze the pathological changes in association with circ_LPAR3 downregulation.

RESULTS

circ_LPAR3 was upregulated in OSCC. Its knockdown in cells could decrease cell survival and mobility and in mice model, could inhibit the tumor growth and angiogenesis. Circ_LPAR3 promoted VEGFC and AKT1 activity by sponging miR-513b-5p in OSCC cells.

CONCLUSION

Knockdown of circ_LPAR3 could inhibit the OSCC progression by sponging miR-513b-5p and activating VEGFC and AKT1.

Hsa_circRNA_0001971 contributes to oral squamous cell carcinoma progression via miR‐186‐5p/Fibronectin type III domain containing 3B axis

Background

Circular RNAs (circRNAs) are closely associated with the progression of oral squamous cell carcinoma (OSCC). circRNA_0001971 has been proved to accelerate the OSCC development. Here, we aim to identify the new molecular mechanism of hsa_circRNA_0001971 (circRNA_0001971) in OSCC.

Methods

The levels of circRNA_0001971, miR‐186‐5p, and fibronectin type III domain containing 3B (FNDC3B) in tissues and cells were verified by qRT‐PCR or Western blotting. The interaction between circRNA_0001971, miR‐186‐5p, and FNDC3B was identified by bioinformatics analysis, luciferase assay, and RIP assay. The effect of circRNA_0001971/miR‐186‐5p/FNDC3B axis on OSCC cell proliferation, migration, and invasion by cell functional experiments including CCK8, wound healing, and transwell assays.

Results

Our study displayed that circRNA_0001971 and FNDC3B were elevated in OSCC, whereas miR‐186‐5p was declined in OSCC. Silencing circRNA_0001971 attenuated the malignancy of OSCC cells by suppressing proliferation, migration, and invasion. In OSCC cells, circRNA_0001971 sponged miR‐186‐5p to enhance FNDC3B. Due to the interaction between circRNA_0001971, miR‐186‐5p, and FNDC3B, FNDC3B overexpression relieved the negative function of silencing circRNA_0001971 in OSCC cells.

Conclusion

Overall, our study discovered that circRNA_0001971 was a tumor promoter in OSCC progression by targeting miR‐186‐5p/FNDC3B axis.

Exosome-delivered circular RNA DLGAP4 induces chemoresistance via miR-143-HK2 axis in neuroblastoma

Accumulating evidence validates that aerobic glycolysis is involved in chemotherapy resistance in human malignant tumors. In the present study, we explored the role of exosome-delivered circular RNA DLGAP4 (circDLGAP4), a novel identified circRNAs, in the chemoresistance of neuroblastoma (NB) cells. Our study demonstrated that doxorubicin-resistant cells expressed higher HK2, accompanied with enhanced glycolysis. In addition, circDLGAP4 was validated to act as a sponge for the HK2-targeting miR-143. As a molecular cargo, exosomes were found to deliver circDLGAP4 from doxorubicin-resistant cells to the sensitive cells. Functionally, exosomal circDLGAP4 enhanced glycolysis and drug resistance via regulating miR-143 and HK2 in NB cells. Consistently, upregulation of HK2 induced by circDLGAP4 or miR-143 inhibitors produced the similar malignant transformation in NB cells. However, knockdown of circDLGA P4 could reversed the drug resistance in the recipient cells. In conclusion, these findings demonstrate that exosome-delivered circDLGAP4 promotes the glycolysis, proliferation, and invasion of sensitive NB cells by regulating miR-143 and HK2, providing a novel link between drug resistance and circDLGAP4/miR-143/HK2 axis in drug-resistant NB.

circPhc3 sponging microRNA‑93‑3p is involved in the regulation of chondrocyte function by mechanical instability in osteoarthritis

Cartilage extracellular matrix (ECM) metabolism disorder caused by mechanical instability is a leading cause of osteoarthritis (OA), but the exact mechanisms have not been fully elucidated. Recent studies have suggested an important role of circular RNAs (circRNAs/circs) in OA. The present study aimed to investigate whether circRNAs might have a role in mechanical instability‑regulated chondrocyte matrix metabolism in OA. The expression levels of circPhc3 in human and mouse OA cartilage samples were measured using reverse transcription‑quantitative PCR and fluorescence in situ hybridization. The effects of circPhc3 on chondrocyte ECM metabolism were further investigated by overexpressing and knocking down circPhc3 in OA chondrocytes. The downstream target of circPhc3 was examined by performing a luciferase reporter assay. The results showed that the expression of circPhc3 was reduced in human and mouse OA cartilage. Moreover, circPhc3 was involved in mechanical loading‑regulated production of ECM and cartilage‑degrading enzymes. Further studies showed that circPhc3 regulated chondrocyte matrix metabolism primarily by binding to microRNA (miR)‑93‑3p, and mechanistic studies found that miR‑93‑3p targeting of FoxO1 was involved in chondrocyte matrix metabolism. Taken together, these results indicated that circPhc3 may serve an important role in the progression of OA and may be a good target for the treatment of OA.

A Concise Review on the Role of CircPVT1 in Tumorigenesis, Drug Sensitivity, and Cancer Prognosis

CircPVT1 (hsa_circ_0001821) is a cancer-related circular RNA (circRNA) that originated from a genomic locus on chromosome 8q24. This locus has been previously found to encode the oncogenic long non-coding RNA PVT1. Expression of this circRNA has been found to be upregulated in diverse neoplastic conditions. CircPVT1 acts as a sponge for miR-125a, miR-125b, miR-124-3p, miR-30a-5p, miR-205-5p, miR-423-5p, miR-526b, miR-137, miR-145-5p, miR-497, miR-30d/e, miR-455-5p, miR-29a-3p, miR-204-5p, miR-149, miR-106a-5p, miR-377, miR-3666, miR-203, and miR-199a-5p. Moreover, it can regulate the activities of PI3K/AKT, Wnt5a/Ror2, E2F2, and HIF-1α. Upregulation of circPVT1 has been correlated with decreased survival of patients with different cancer types. In the current review, we explain the oncogenic impact of circPVT1 in different tissues based on evidence from in vitro, in vivo, and clinical investigations.

Non-coding RNAs in necroptosis, pyroptosis and ferroptosis in cancer metastasis

Distant metastasis is the main cause of death for cancer patients. Recently, the newly discovered programmed cell death includes necroptosis, pyroptosis, and ferroptosis, which possesses an important role in the process of tumor metastasis. At the same time, it is widely reported that non-coding RNA precisely regulates programmed death and tumor metastasis. In the present review, we summarize the function and role of necroptosis, pyrolysis, and ferroptosis involving in cancer metastasis, as well as the regulatory factors, including non-coding RNAs, of necroptosis, pyroptosis, and ferroptosis in the process of tumor metastasis.

Circular RNAs Regulate Glucose Metabolism in Cancer Cells

Circular RNAs (circRNAs) were originally thought to result from RNA splicing errors. However, it has been shown that circRNAs can regulate cancer onset and progression in various ways. They can regulate cancer cell proliferation, differentiation, invasion, and metastasis. Moreover, they modulate glucose metabolism in cancer cells through different mechanisms such as directly regulating glycolytic enzymes and glucose transporter (GLUT) or indirectly regulating signal transduction pathways. In this review, we elucidate on the role of circRNAs in regulating glucose metabolism in cancer cells, which partly explains the pathogenesis of malignant tumors, and provides new therapeutic targets or new diagnostic and prognostic markers for human cancers.

Research Progress of circRNAs in Head and Neck Cancers

Circular RNAs (circRNAs) are a novel type of non-coding RNAs. Because of their characteristics of a closed loop structure, disease- and tissue-specificity, and high conservation and stability, circRNAs have the potential to be biomarkers for disease diagnosis. Head and neck cancers are one of the most common malignant tumors with high incidence rates globally. Affected patients are often diagnosed at the advanced stage with poor prognosis, owing to the concealment of anatomic sites. The characteristics, functions, and specific mechanisms of circRNAs in head and neck cancers are increasingly being discovered, and they have important clinical significance for the early diagnosis, treatment, and prognosis evaluation of patients with cancer. In this study, the generation, characteristics, and functions of circRNAs, along with their regulatory mechanisms in head and neck cancers have been summarized. We report that circRNAs interact with molecules such as transcription and growth factors to influence specific pathways involved in tumorigenesis. We conclude that circRNAs have an important role to play in the proliferation, invasion, metastasis, energy and substance metabolism, and treatment resistance in cancers.

Down-regulating circular RNA_0004674 delays the progression of oral squamous cell carcinoma through microRNA-377-3p/THBS1 axis

OBJECTIVE

Circular RNAs (CircRNAs) are of great significance in oral squamous cell carcinoma (OSCC) cell progression. Insufficiently, the performance of Circ_0004674 has not been specified in the disease, which alighted our desire to unmask its actions in OSCC cell progression with microRNA (miR)-377-3p and thrombospondin-1 (THBS1).

METHODS

OSCC expression chip were collected through GEO database and analyzed. The upstream mechanism of THBS1 was predicted through databases. OSCC cancer tissues and normal tissues were resected, in which Circ_0004674, miR-377-3p and THBS1 expression were examined. The relationship of Circ_0004674, miR-377-3p and THBS1 was identified. Circ_0004674- and/or miR-377-3p-related oligonucleotides were transfected into CAL27 cells for detecting cell biological behaviors. Tumors in mice were implanted to monitor the tumor-forming ability of cells.

RESULTS

THBS1 showed high expression in the three OSCC chips, and it was enriched in PI3K-AKT signaling pathway. The upstream mechanism of THBS1 predicted that Circ_0004674 regulated THBS1 through miR-377-3p. Circ_0004674 and THBS1 levels were enhanced while miR-377-3p level was reduced in OSCC. Down-regulating Circ_0004674 restricted the growth of CAL27 cells in vivo and in vitro. Restoring miR-377-3p, the target gene of Circ_0004674, destroyed CAL27 cell progression and tumor growth. miR-377-3p suppression rescued the effects of down-regulated Circ_0004674 on OSCC. THBS1 was negatively mediated by miR-377-3p.

CONCLUSION

It is clarified that depleting Circ_0004674 mediates miR-377-3p to restrain THBS1, after which OSCC cell progression can be suppressed. It widens the way to control OSCC from a novel perspective.

Lnc2Cancer 3.0: an updated resource for experimentally supported lncRNA/circRNA cancer associations and web tools based on RNA-seq and scRNA-seq data

An updated Lnc2Cancer 3.0 (http://www.bio-bigdata.net/lnc2cancer or http://bio-bigdata.hrbmu.edu.cn/lnc2cancer) database, which includes comprehensive data on experimentally supported long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) associated with human cancers. In addition, web tools for analyzing lncRNA expression by high-throughput RNA sequencing (RNA-seq) and single-cell RNA-seq (scRNA-seq) are described. Lnc2Cancer 3.0 was updated with several new features, including (i) Increased cancer-associated lncRNA entries over the previous version. The current release includes 9254 lncRNA-cancer associations, with 2659 lncRNAs and 216 cancer subtypes. (ii) Newly adding 1049 experimentally supported circRNA-cancer associations, with 743 circRNAs and 70 cancer subtypes. (iii) Experimentally supported regulatory mechanisms of cancer-related lncRNAs and circRNAs, involving microRNAs, transcription factors (TF), genetic variants, methylation and enhancers were included. (iv) Appending experimentally supported biological functions of cancer-related lncRNAs and circRNAs including cell growth, apoptosis, autophagy, epithelial mesenchymal transformation (EMT), immunity and coding ability. (v) Experimentally supported clinical relevance of cancer-related lncRNAs and circRNAs in metastasis, recurrence, circulation, drug resistance, and prognosis was included. Additionally, two flexible online tools, including RNA-seq and scRNA-seq web tools, were developed to enable fast and customizable analysis and visualization of lncRNAs in cancers. Lnc2Cancer 3.0 is a valuable resource for elucidating the associations between lncRNA, circRNA and cancer.

The functions and clinical significance of circRNAs in hematological malignancies

With covalently closed circular structures, circular RNAs (circRNAs) were once misinterpreted as by-products of mRNA splicing. Being abundant, stable, highly conserved, and tissue-specific, circRNAs are recently identified as a type of regulatory RNAs. CircRNAs bind to certain miRNAs or proteins to participate in gene transcription and translation. Emerging evidence has indicated that the dysregulation of circRNAs is closely linked to the tumorigenesis and treatment response of hematological malignancies. CircRNAs play critical roles in various biological processes, including tumorigenesis, drug resistance, tumor metabolism, autophagy, pyroptosis, and ferroptosis. The N6-methyladenosine modification of circRNAs and discovery of fusion-circRNAs provide novel insights into the functions of circRNAs. Targeting circRNAs in hematological malignancies will be an attractive treatment strategy. In this review, we systematically summarize recent advances toward the novel functions and molecular mechanisms of circRNAs in hematological malignancies, and highlight the potential clinical applications of circRNAs as novel biomarkers and therapeutic targets for future exploration.