Silencing circular RNA hsa_circ_009755 promotes growth and metastasis of oral squamous cell carcinoma

Propofol inhibits the proliferation, invasion, migration, and angiogenesis of oral squamous cell carcinoma through circ_0008898-mediated pathway

Propofol has been shown to inhibit oral squamous cell carcinoma (OSCC) progression. However, it is not clear whether propofol mediates OSCC progression through regulating circular RNA (circRNA) network. Quantitative real-time PCR was used to detect circ_0008898, miR-545-3p, and CT10 regulator of kinase-like protein (CRKL) expression. Cell functions were determined using CCK8 assay, Edu staining, MTT assay, transwell assay, wound healing assay, tube formation assay, and flow cytometry. Protein levels were examined by western blot analysis. RNA interaction was confirmed by dual-luciferase reporter assay and RIP assay. Our data showed that propofol repressed OSCC cell proliferation, invasion, migration, angiogenesis, and promoted apoptosis. circ_0008898 was highly expressed in OSCC, and its expression could be decreased by propofol. circ_0008898 silencing aggravated the suppressive effect of propofol on OSCC progression. In the mechanism, circ_0008898 could target miR-545-3p to positively regulate CRKL. MiR-545-3p inhibitor abolished the regulation of circ_0008898 silencing on propofol-mediated OSCC cell progression. MiR-545-3p inhibited the progression of propofol-treated OSCC cells, and this effect was reversed by CRKL overexpression. Also, circ_0008898 knockdown reduced OSCC tumor growth by regulating miR-545-3p/CRKL. In conclusion, propofol suppressed OSCC progression, which was achieved through regulating the circ_0008898/miR-545-3p/CRKL axis.

Circular hsa_circ_0020377 regulates KLF7 by targeting miR-194-5p to facilitate tumor cell malignant behaviors and glycolysis in oral squamous cell carcinoma progression

Oral squamous cell carcinoma (OSCC) is a common malignant tumor with high recurrence, metastasis rates, and poor prognosis. Numerous studies discover that circular RNA (circRNA) is closely associated with OSCC progression. Hsa_circ_0020377 has been aberrantly expressed in OSCC, but its role in tumor growth and metastasis remains largely unclear. Hsa_circ_0020377, microRNA-194-5p (miR-194-5p), and Krüppel-like factor 7 (KLF7) contents were determined by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferative, cycle progression migration, and invasion were measured using 5-ethynyl-2'-deoxyuridine (EdU), Cell Counting Kit-8 (CCK-8), flow cytometry, wound healing, and Transwell assays. The glycolysis level was detected via specific kits. Cyclin D1, E-cadherin, hexokinase 2 (HK2), and KLF7 protein levels were detected via western blot. Using predicting bioinformatics software, the binding between miR-194-5p and hsa_circ_0020377 or KLF7 was verified using a dual-luciferase reporter and RNA Immunoprecipitation (RIP). Beyond that, a xenograft tumor model was used to analyze the role of hsa_circ_0020377 on tumor cell growth in vivo. Increased hsa_circ_0020377 and KLF7 and reduced miR-194-5p were found in OSCC tissues and cell lines. Loss-of-function experiments proved that hsa_circ_0020377 depletion might block OSCC cell proliferation, cycle progression, migration, invasion, and glycolysis in vitro. In xenograft mouse models, hsa_circ_0020377 silencing might suppress tumor growth. In addition, mechanism research suggested that hsa_circ_0020377 could bind with miR-194-5p and enhance its target gene (KLF7), thereby affecting OSCC development. These results broaden our insights regarding the regulation of OSCC progression via circRNA and act as a reference for future clinical studies in OSCC diagnosis and treatment.

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.

Diagnostic and prognostic value of circRNAs expression in head and neck squamous cell carcinoma: A meta-analysis

Background

Circular RNAs (circRNAs) have been found to have potential biological applications against tumors in humans. This study aimed to evaluate the diagnostic, prognostic, and clinicopathological value of circRNAs in head and neck squamous cell carcinoma (HNSCC).

Methods

The PubMed, Web of Science, EMBASE, and the Cochrane Library were comprehensively searched for the relevant studies before October 20, 2021. Statistical analysis was performed based on STATA 15.0, Meta‐DiSc 1.4, and RevMan 5.3 software.

Results

A total of 55 reports regarding 56 kinds of circRNA were studied in this meta‐analysis, including 23, 38, and 26 articles on diagnosis, prognosis, and clinicopathological features, respectively. The pooled sensitivity, specificity, and area under the curve (AUC) of the summary receiver‐operating characteristic curve (SROC) were 0.78, 0.84, and 0.87, respectively. Besides, the upregulation of oncogenic circRNAs was significantly associated with poorer overall survival (OS) (HR=2.25, p < 0.05) and disease‐free interval (DFS) (HR=1.92, p < 0.05). In contrast, the elevated expression of tumor suppressor circRNAs was associated with a favorable prognosis (HR=0.50, p < 0.05). In addition, the high expression of oncogenic circRNAs was associated with the tumor size (OR=3.59, p < 0.05), degree of differentiation (OR=1.89, p < 0.05), TNM stage (OR=2.35, p < 0.05), lymph node metastasis (OR=1.85, p < 0.05), and distant metastasis (OR=3.42, p < 0.05). Moreover, the expression of tumor suppressor circRNAs was associated with improved clinicopathological features (lymph node metastasis: OR=0.25, p < 0.05).

Conclusions

CircRNAs could serve as potential predictive indicators and be useful for the diagnosis, prognosis, and identification of clinicopathological features in HNSCC.

Identification of plasma hsa_circ_0000190 and 0001649 as biomarkers for predicting the recurrence and treatment response of patients with oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a type of malignancy characterized by high relapse and recurrence rates in the late stage despite optimal surgical intervention and postoperative chemoradiotherapy. Because the management of relapse following definitive treatment is challenging, accurate risk stratification is of clinical significance to improve treatment outcomes. Circular RNAs (circRNAs) are noncoding RNAs featured with cell-type specificity and high stability, owing to their circular structure, making these molecules excellent biomarkers for a variety of diseases.

METHODS

The levels of hsa_circ_0000190 and 0001649 in plasma samples from 30 healthy controls and 66 OSCC patients were determined by droplet digital polymerase chain reaction. The same primer sets were used with PCR to examine the expression of these two circRNAs in cancerous and adjacent normal tissues. A receiver operating characteristics curve was generated to evaluate the diagnostic value. The Kaplan-Meier method with a log-rank test was used for survival analysis.

RESULTS

We identified two circRNAs as potential biomarkers for OSCC, showing that the plasma level of hsa_circ_0000190 was significantly decreased in the late stage and marginally correlated with the development of second primary OSCC. We also found that the decreased plasma hsa_circ_0001649 was correlated with the recurrence and poor prognosis of patients. Additionally, we found that high plasma hsa_circ_0000190, but not hsa_circ_0001649, possibly predicted a better response of patients to induction chemotherapy.

CONCLUSION

Our study demonstrated the potential of biomarkers in plasma to inform not just the tumor but the entire oral cavity, thereby offering a prediction for early recurrence and second primary OSCC. The plasma circRNAs remain valuable for OSCC, albeit the easy accessibility to the oral cavity.

Mechanism for Bioactive Nanomaterial circ0024831 Regulation of Staphylococcal Nuclease Domain Containing 1 via RNA Methylation Recognition in Osteosarcoma

Bioactive nanomaterial circular RNA (circRNA) is an important non-coding RNA with a strong specificity, stable structure and high expression abundance. It can affect many diseases and physiological processes and may become a new way of disease diagnosis and targeted therapy. Recent studies have shown that Staphylococcal Nuclease Domain-Containing Protein 1 (SND1) can recognize N6-methyladenine (M6A) modified mRNA and regulate target mRNA stability. It can then control the expression of a series of downstream genes. However, whether SND1 can directly combine with circRNA and regulate its stability and function are new issues to be discussed. Results showed bioactive nanomaterial circ0024831 could directly bind to the Tudor domain of SND1 in the cytoplasm to block the recognition of SND1 to M6A modified RNA thus reducing the stability of downstream target gene mRNA and inhibiting the expression of downstream regulatory proteins. The down-regulation of circ0024831 expression in osteosarcoma cells relieved inhibition of SND1 which lead to change of tumor-related gene expression profile, promoting the occurrence and development of osteosarcoma.

Treponema denticola Promotes OSCC Development via the TGF-β Signaling Pathway

Numerous studies have demonstrated an association between periodontitis and oral squamous cell carcinoma (OSCC), and periodontal pathogens such as Treponema denticola are implicated in the pathogenesis of OSCC. Previous studies have mainly focused on T. denticola surface proteins—for example, chymotrypsin-like proteinase, which was detected in the majority of orodigestive tumor tissues. T. denticola may influence the development of OSCC. Nevertheless, the potential direct regulatory mechanism of T. denticola in OSCC is still unclear. Therefore, this study aimed to explore the direct effect of T. denticola on OSCC cell proliferation and elucidate potential mechanisms of T. denticola in contributing to cell proliferation. A series of in vitro experiments (e.g., CCK-8, EdU, flow cytometry) were performed to explore the effect of T. denticola on cell proliferation, cell cycle, and apoptosis. Mice experiments were performed to explore the effect of T. denticola on tumor growth. Whole mRNA transcriptome sequencing and quantitative real-time polymerase chain reaction were performed to explore the intracellular signaling pathway. Our study found that T. denticola could invade Cal-27 cells and directly promote cell proliferation, regulate the cell cycle, and inhibit apoptosis. T. denticola could also promote the growth of OSCC tumors in mice, and it upregulated Ki67 expression. Regarding the mechanism, T. denticola could promote the development of OSCC by activating the TGF-β pathway. In conclusion, T. denticola could promote OSCC cell proliferation directly, and the mechanism was associated with intracellular TGF-β pathway activation.

Diagnostic Value of CircRNAs as Potential Biomarkers in Oral Squamous Cell Carcinoma: a Meta-Analysis

Introduction

Circular RNAs (CircRNAs), an emerging non-coding RNA, have been demonstrated to be involved in tumorigenesis, metastasis, and cancer progression, and could represent novel potential biomarkers for diagnosing oral squamous cell carcinoma (OSCC). However, no meta-analysis has investigated the diagnostic role of circRNAs in OSCC. Hence, to investigate whether circRNAs could serve as specific biomarkers for OSCC, the present systematic review and meta-analysis evaluated the diagnostic efficiency of circRNAs in patients with OSCC.

Materials and Methods

A thorough search of online databases (Pubmed, Web of Science, Embase, and the Cochrane Library) was conducted to collect relevant studies up to March 30th, 2021. All eligible studies were case-control studies. The quality of each study was evaluated by the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. STATA (version 15.1) and Review Manager (version 5.4) were employed to conduct the meta-analysis, and the PRISMA statement was adopted in this study.

Results

A total of 16 studies were included in the meta-analysis, with five studies on upregulated circRNAs, and 11 on downregulated circRNAs. The enrolled studies that met our eligibility criteria all derived from China. The pooled sensitivity (SEN), specificity (SPE), diagnostic odds ratio (DOR), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and the area under receiver operating characteristics curve (AUC) with the 95% confidence intervals (95% CIs) were 0.74 (0.69–0.79), 0.79 (0.73–0.84), 10.74 (7.81–14.77), 3.50 (2.78–4.45), 0.33 (0.27–0.39) and 0.83 (0.79–0.86), respectively. The subgroup analysis demonstrated that serum, plasma, and saliva specimens had a better diagnostic performance than tissue samples, with a high value of sensitivity, specificity, DOR, and AUC values. The results also showed that the subgroups of upregulated circRNAs and a sample size of ≥100 manifested higher specificity, DOR, and AUC for cancer detection than downregulated circRNAs and a sample size of < 100.

Conclusions

A strong association was demonstrated between the dysregulated expression of circRNAs and the diagnosis of OSCC. Hence, circRNAs have the potential to function as promising biomarkers and therapeutic targets for OSCC.

Systematic Review Registration

PROSPERO, number CRD42021256857.