LINC00887 Acts as an Enhancer RNA to Promote Medullary Thyroid Carcinoma Progression by Binding with FOXQ1.

BACKGROUND: Medullary thyroid carcinoma (MTC) is a rare but aggressive endocrine malignancy that originates from the parafollicular C cells of the thyroid gland. Enhancer RNAs (eRNAs) are non-coding RNAs transcribed from enhancer regions, which are critical regulators of tumorigenesis. However, the roles and regulatory mechanisms of eRNAs in MTC remain poorly understood. This study aims to identify key eRNAs regulating the malignant phenotype of MTC and to uncover transcription factors involved in the regulation of key eRNAs. METHODS: GSE32662 and GSE114068 were used for the identification of differentially expressed genes, eRNAs, enhancers and enhancer-regulated genes in MTC. Metascape and the transcription factor affinity prediction method were used for gene function enrichment and transcription factor prediction, respectively. qRT-PCR was used to detect gene transcription levels. ChIP-qPCR was used to assess the binding of histone H3 lysine 27 acetylation (H3K27ac)-enriched regions to anti- H3K27ac. RIP-qPCR was used to detect the binding between FOXQ1 and LINC00887. CCK8 and Transwell were performed to measure the proliferation and invasion of MTC cells, respectively. Intracellular reactive oxygen species (ROS) levels were quantified using a ROS assay kit. RESULTS: Four eRNAs (H1FX-AS1, LINC00887, MCM3AP-AS1 and A1BG-AS1) were screened, among which LINC00887 was the key eRNA promoting the proliferation and invasion of MTC cells. A total of 135 genes controlled by LINC00887-regulated enhancers were identified; among them, BCL2, PRDX1, SFTPD, TPO, GSS, RAD52, ZNF580, and ZFP36L1 were significantly enriched in the "ROS metabolic process" term. As a transcription factor regulating genes enriched in the "ROS metabolic process" term, FOXQ1 could recruit LINC00887. Overexpression of FOXQ1 restored LINC00887 knockdown-induced downregulation of GSS and ZFP36L1 transcription in MTC cells. Additionally, FOXQ1 overexpression counteracted the inhibitory effects of LINC00887 knockdown on the proliferation and invasion of MTC cells and the promotion of intracellular ROS accumulation induced by LINC00887 knockdown. CONCLUSION: LINC00887 was identified as a key eRNA promoting the malignant phenotype of MTC cells. The involvement of FOXQ1 was essential for LINC00887 to play a pro-tumorigenic role in MTC. Our findings suggest that the FOXQ1/LINC00887 axis is a potential therapeutic target for MTC.

hsa­miR­216a­3p regulates cell proliferation in oral cancer via the Wnt3a/ß­catenin pathway.

Oral cancer is one of the leading causes of death worldwide, with a reported 5­year survival rate of ~50% after treatment. The treatment measures for oral cancer are very expensive and affordability is low. Thus, it is necessary to develop more effective therapies to treat oral cancer. A number of studies have found that miRNAs are invasive biomarkers and have therapeutic potential in a variety of cancers. The present study included 30 oral patients and 30 healthy controls. Clinicopathological characteristic and miR­216a­3p/ß­catenin expression level of 30 oral cancer patients were analyzed. In addition, two oral cancer cell lines (HSC­6 and CAL­27) were used for mechanism­of­action study. The expression level of miR­216a­3p was higher in oral cancer patients compared with healthy controls and positively associated with tumor stage. Inhibition of miR­216a­3p potently suppressed cell viability and induced apoptosis of oral cancer cells. It was found that effects of miR­216a­3p on oral cancer were through Wnt3a signaling. It was also found that the expression level of ß­catenin was higher in oral cancer patients compared with healthy controls and positively associated with tumor stage; the effects of miR­216a­3p on oral cancer were through ß­catenin. In conclusion, miR­216a­3p and the Wnt­ß­catenin signaling pathway may be interesting candidates to develop effective therapies for oral cancers.

Long noncoding RNA MEG3 inhibits oral squamous cell carcinoma progression via GATA3.

Oral squamous cell carcinoma (OSCC) accounts for about 90% of oral cancers. Expression of the long noncoding RNA (lncRNA) maternally expressed 3 (MEG3) has previously been reported to be downregulated in OSCC, and its overexpression can inhibit proliferation, migration, and invasion and promote apoptosis of OSCC cells. However, the mechanism underlying MEG3 downregulation in OSCC has not been well characterized. Here we report that low expression of MEG3 is caused by H3K27me3 modification of the MEG3 gene locus, and this is associated with the poor prognosis of OSCC. Overexpression of MEG3 inhibited the proliferation and invasion of OSCC cells. We observed that MEG3 was modified by m6A and bound to YTHDC1. Enhancer-controlled genes positively regulated by MEG3 were functionally enriched for the 'negative regulation of Wnt signaling pathway' term, as determined using metascape. GATA3 was predicted to be a transcription factor for these genes, and was demonstrated to bind to MEG3. Knockdown of GATA3 countered the effects on proliferation, invasion, and increased transcription of HIC1 and PRICKLE1 induced by MEG3 overexpression. In conclusion, our data suggest that MEG3 is downregulated in OSCC due to trimethylation of H3K27 at the MEG3 gene locus. The inhibitory effect of MEG3 on proliferation and invasion of OSCC cells was dependent on the binding of GATA3.

Biomimetic Nanosystems for the Synergistic Delivery of miR-144/451a for Oral Squamous Cell Carcinoma

Background: The miR-144/451a cluster acts as a tumor suppressor in various tumors by synergistically inhibiting the proliferation, migration, and invasion of oral squamous cell carcinoma (OSCC). Aims: To achieve the synergistic delivery of the miR-144/451a cluster for OSCC treatment by constructing chitosan nanoparticles (CAs) camouflaged with macrophage membranes. Study Design: A cell-culture study. Methods: CAs were prepared using the ionic cross-linking method, and biomimetic nanoparticles coloaded with the miR-144/451a cluster (miR-144-source of macrophage-derived exosomes [MEXO]/CA-miR-451a) were prepared using the uptake­efflux method. The MEXO was detected by a bicinchoninic acid assay. The as-prepared biomimetic nanoparticles were then characterized to determine their protective effects on microRNAs (miRNAs). Moreover, the influence of the miR-144-MEXO/CA-miR-451a nanoparticles on the proliferation, migration, and invasion of OSCCs was evaluated. Finally, the effects of the biomimetic system on the expression of calcium-binding protein 39 (CAB39) and migration inhibitory factor (MIF) were detected using the real-time polymerase chain reaction and Western blot. Results: After coating the CAs with MEXO, their particle size increased from 113.1 ± 3.4 nm to 143.2 ± 14 nm, and their surface potential decreased from 26.34 ± 0.4 mV to −10.3 ± 1.6 mV. The expression of the MEXO marker protein was also observed on the biomimetic nanoparticles' surface. The system can protect miRNAs from RNase A degradation. Compared with the CAs cotransfected with free miR-144/451a cluster, CAs that are coloaded with miR- 144-MEXO/CA-miR-451a nanoparticles substantially reduced the viability (p < 0.001), migration (p = 0.023), and invasion (p = 0.004) of OSCC. These findings revealed the successful construction of biomimetic nanoparticles coloaded with the miR-144/451a cluster. CAB39 and MIF expression in OSCC treated with miR-144-MEXO/ CA-miR-451a nanoparticles have significantly decreased compared with the miR-144/451a group (p < 0.05). Thus, the nanoparticles can effectively improve the inhibitory effects of the miR-144/451a cluster on OSCC. Conclusion: This study provided a new idea for the application of gene cotransfection to tumor treatment.

Screening and cellular validation of prognostic genes regulated by super enhancers in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is the leading cause of death in patients with head and neck cancer. Reliable biomarkers to guide treatment decisions for OSCC remain scarce. The purpose of this study was to identify novel prognostic markers regulated by super enhancers in OSCC. Eight modules were obtained by weighted gene co-expression network analysis (WGCNA), among which MEblue module had the highest correlation with tumor stage, alcohol consumption and smoking. There were 41 genes regulated by super enhancers in MEblue module. Functional analysis showed that 41 super enhancer-regulated genes were involved in cancer progression. A total of twenty transcription factors of the 41 genes were predicted. Prognostic analysis of the 41 genes and the top 5 transcription factors showed that patients with high expression of AHCY, KCMF1, MANBAL and TFDP1 had a poor prognosis. Immunohistochemical analysis showed that AHCY, KCMF1 and MANBAL were highly expressed in OSCC tissue. Cellular experiment demonstrated that TFDP1 promoted AHCY, KCMF1 and MANBAL expression by binding to the super enhancers of these genes. Knockdown of TFDP1, AHCY, KCMF1 and MANBAL inhibited the proliferation of OSCC cells. In conclusion, AHCY, KCMF1 and MANBAL were recognized as super enhancer-regulated prognostic biomarkers regulated by TFDP1 in OSCC.

Maternally expressed 3 inhibits the biological activity of oral squamous cell carcinoma SCC25 and CAL27 cell lines.

The abnormal expression of long non-coding RNA (lncRNA) maternally expressed 3 (MEG3) is closely related to several tumor diagnosis and progression, such as endometrial carcinoma and ovarian cancer. However, the role of MEG3 in oral squamous cell carcinoma (OSCC) is rarely reported. The current study aimed to evaluate the expression of lncRNA MEG3 in OSCC tissues and cell lines and its effect on the biological behavior of OSCC cell lines. The expression of lncRNA MEG3 in the OSCC tissues and cell lines was detected by reverse transcription-quantitative (RT-q) PCR. The relationship between MEG3 expression and the clinicopathologic characteristics and prognosis of patients with OSCC was analyzed. The lncRNA MEG3 overexpression plasmid and control plasmid were transfected into SCC25 and CAL27 cell lines using the lipofectin method. MTT assay was performed to detect the growth and proliferation of the cell lines. Transwell chamber test was used to detect changes in cell migration and invasion. Flow cytometry was employed to detect changes in apoptosis. Western blotting and RT-qPCR were conducted to detect the expression of the p53 gene. The expression of lncRNA MEG3 in the OSCC tissues and cell lines was significantly compared with normal tissues and cell lines, respectively. The expression level of MEG3 was related to clinical stage, lymph node metastasis, distant metastasis and survival status. Overexpression of lncRNA MEG3 inhibited the proliferation, migration, and invasion of SCC25 and CAL27 cell lines, induced apoptosis and promoted the expression of p53 gene. lncRNA MEG3 played the role of a tumor inhibitor gene and significantly inhibited the biological activity of OSCC cell lines, which may provide a novel idea for molecular targeted therapy of OSCC.

Antitumor Activity of Cabazitaxel and MSC-TRAIL Derived Extracellular Vesicles in Drug-Resistant Oral Squamous Cell Carcinoma.

INTRODUCTION: TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) can induce apoptosis in a variety of cancer cells. However, drug resistance of tumor and short half-life seriously affects its clinical targeted therapy. Cabazitaxel (CTX) is a taxane drug, which can induce apoptosis or autophagy by inhibiting the phosphorylation of PI3K/Akt/mTOR and sensitive to some drug-resistant tumors. Therefore, we explored the possibility of developing a mesenchymal stem cell-derived exosomes (MSC-EXO) vector for oral squamous cell carcinoma (OSCC) to deliver CTX/TRAIL combinations. METHODS: After ultracentrifugation and dialysis, CTX/TRAIL loaded exosomes transfected MSC (MSCT)-derived exosome (EXO) (MSCT-EXO/CTX) were isolated and purified. The expression of CD63, CD9 and TRAIL was detected by BCA to confirm the origin of EXO. High-performance liquid chromatography (HPLC) was used to determine the drug loading of VPF and draw the in vitro release profile. MTT assay, flow cytometry and Western blot were used to detect the antitumor effect of MSCT-EXO/CTX in vitro. Subsequently, the antitumor effect of MSCT-EXO/CTX in vivo was verified by mouse model. RESULTS: The diameter of the membrane particles was about 60-150 nm. We have proved that the incorporation and release of CTX in MSCT-EXO can inhibit the activation of PI3K, Akt and mTOR, which is a possible synergistic mechanism of CTX. MSCT-EXO and CTX can induce the apoptosis of SCC25 tumor cells in a dose-dependent manner and exert a good synergistic effect in the proportion range of 10:1-5:1. The inherent activity of MSCT-EXO and the direct effect of MSCT-EXO/CTX on OSCC confirm that MSCT-EXO/CTX makes MSCT-EXO and CTX have an efficient synergistic effect and a highly effective pharmacological inhibition on cancer cells, as verified by the subsequent mouse model. MSCT-EXO/CTX showed the lowest relative tumor volume and the highest tumor inhibition rate (P<0.05) in vivo. CONCLUSION: An MSCT-EXO-based CTX delivery system might be an effective anticancer method.

MicroRNA-218 inhibits type I interferon production and facilitates virus immune evasion via targeting RIG-I.

The host protective immunity against viral infection requires the effective detection of viral antigens and the subsequent production of type I interferons (IFNs) by host immune cells. Retinoic acid-inducible gene I (RIG-I) is the crucial signaling element responsible for sensing viral RNA component and initiating the downstream antiviral signaling pathways, leading to the production of type I IFNs. In this work, we identified microRNA-218 (miR-218) as a new virus-induced miRNA that dampens the expression of RIG-I in mouse and human macrophages, leading to the impaired production of type I IFNs. Interfering miR-218 expression rescued RIG-I-mediated antiviral signaling and thus protected macrophages from viral infection. Hence, our results provide new understanding of miRNA-mediated viral immune evasion and may be potentially useful for the treatment of viral infection in the future.

[Effect of EDTA and hyaluronic acid on the activity of periodontal ligament fibroblasts and the expression of cytokines].

PURPOSE: To investigate the effect of ethylenediaminetetraacetic acid (EDTA) and hyaluronic acid (HA) on the activity of periodontal ligament fibroblasts (PDLFs) and the expression of cytokines. METHODS: Twelve wisdom teeth extracted due to orthodontics treatment were selected and prepared into 5 mm×4 mm root pieces, then divided into EDTA group, HA group, EDTA+HA group and untreated group according to different treatment methods. They were placed in the well plate and PDLFs inoculated on the root piece. After 24 and 48 h of inoculation, the cell proliferation of each group was detected by MTT assay. The adhesion of PDLFs was observed under microscope. The inflammatory cytokines (IL-6, IL-8 and IL-1ß and TNF-α) levels produced by PDLFs were determined by ELLISA and Western Blot. SPSS 22.0 software package was used for statistical analysis. RESULTS: After 24 h and 48 h inoculation, all the treatments promoted cell proliferation and adhesion of PDLFs compared with the untreated group, and the combined treatment promoted cell proliferation and adhesion significantly better than single treatment (P<0.05). The cell proliferation and adhesion effect of EDTA group and HA group increased with the inoculation time, without significant difference between the groups (P>0.05). The results of ELLISA and Western blot showed that compared with the untreated group, the treatment groups inhibited the expression of inflammatory factors IL-6, IL-1ß and TNF-α, and promoted the expression of IL-8, and the effect of EDTA+HA group was much more significant(P<0.05). CONCLUSIONS: EDTA+HA can significantly promote the growth of periodontal ligament fibroblasts and inhibit the expression of inflammatory cytokines, which may be related to its ability to enhance the adhesion of fibroblasts and then improve their viability.

Pathway analysis of a genome­wide association study on a long non­coding RNA expression profile in oral squamous cell carcinoma.

Long non­coding RNAs (lncRNAs) have been consistently demonstrated to be involved in oral squamous cell carcinoma (OSCC) as either tumor oncogenes or tumor suppressors. However, the underlying mechanisms of OSCC tumorigenesis and development have not yet been fully elucidated. The expression profiles of mRNAs and lncRNAs in OSCC were analyzed by a microarray assay. To verify the results of the microarray, 10 differentially expressed lncRNAs were randomly selected and measured by quantitative RT­PCR (qRT­PCR). Gene Ontology (GO) and metabolic pathway analyses were performed to analyze gene function and identify enriched pathways. Subsequently, two independent algorithms were used to predict the target genes of the lncRNAs. We identified 2,294 lncRNAs and 1,938 mRNAs that were differentially expressed in all three OSCC tissues by a microarray assay. Through the construction of co­expression networks of differentially expressed genes, 4 critical lncRNAs nodes were identified as potential key factors in the pathogenesis of OSCC. Expression of the 4 critical lncRNA nodes was not associated with age, sex, smoking or tumor location (P>0.05) but was positively correlated with clinical stage, lymphatic metastasis, distant metastasis and survival status (P<0.05). Kaplan­Meier analysis demonstrated that low expression levels of these 4 critical lncRNA nodes contributed to poor median progression­free survival (PFS) and overall survival (OS) (P<0.05). GO and pathway analyses indicated that the functions and enriched pathways of many dysregulated genes are associated with cancer. Potential target genes of dysregulated lncRNAs were enriched in 43 metabolic pathways, with cancer pathways being the primary enrichment pathways. In summary, we analyzed the profile of lncRNAs in OSCC and identified the functions and enriched metabolic pathways of both dysregulated mRNAs and the target genes of dysregulated lncRNAs, providing new insights into molecular markers and therapeutic targets for OSCC.

Role of the Chinese herbal medicine xianhuayin on the reversal of premalignant mucosal lesions in the golden hamster buccal pouch.

AIM: To investigate the role of the Chinese herbal medicine Xianhuayin on the reversal of 7,12-dimethylbenz[a]anthracene (DMBA)-induced premalignant mucosal lesions in the oral buccal pouch of golden hamsters. METHODOLOGY: The animals were randomly divided into a non-diseased control group (n=5) and an experimental group including 50 animals in which the buccal mucosa had been painted with DMBA (0.5% in acetone) to generate an oral mucosa premalignant lesion. Animals in the experimental group were further divided into Xianhuayin-treated group (n=30), untreated premalignant lesion group (n=10) and normal saline (NS)-treated group (n=10). The cheek (buccal) pouch mucosa of the golden hamsters in each group was observed with light and electron microscopy eight weeks after intragastric administration with NS or Xianhuayin. RESULTS: In the non-diseased control group, the buccal mucosa was keratinized and stratified squamous epithelium under a light microscope. In the untreated premalignant lesion group, variable degrees of epithelial dysplasia was observed. The irregular epithelial mucosa gradually became distinct in the Xianhuayin-treated group. Scanning electronic microscopic (SEM) analysis showed that surface of the cells exhibited honeycomb structures in the hamster of untreated-group. The cells were morphologically irregular, overlapped and loosened in the untreated premalignant lesion group. Most of the cell surface exhibited honeycomb structure in the Xianhuayin-treated group. Transmission electronic microscopic (TEM) analysis showed that buccal mucosal epithelial cells were morphologically regular in the non-diseased control group. Desmosomes and tonofibrils were reduced and the nucleus was morphologically irregular in the untreated premalignant lesion group. In the Xianhuayin-treated group, the widening intercellular gap was gradually reduced, desmosomes and the cells becoming morphologically regular. No significant difference was observed between the hamsters in NS-treated group and those in the untreated premalignant lesion group. Significant therapeutic efficacy was observed in the group receiving Xianhuayin. CONCLUSION: Xianhuayin is effective in the reversal of DMBA-induced premalignant lesions in the buccal pouch of golden hamsters.