Oral Squamous Cell Carcinoma Tumor Tissues Research Articles

Dysregulation of a novel m6A regulator YWHAG is correlated with metastasis and poor prognosis in oral squamous cell carcinoma – A cross-sectional study

ObjectiveThis study aimed to investigate the role of a novel m6A and cell cycle regulator YWHAG in oral squamous cell carcinoma (OSCC) by analyzing its expression and functional implications. DesignTumor samples (n = 51) and adjacent non-tumor samples (n = 38) were collected from patients with OSCC, and cell lines were processed. YWHAG mRNA expression was assessed using quantitative reverse transcription PCR (RT-qPCR) analysis. Various tools, such as UALCAN, Protein-Atlas analysis, TIMER 2.0, and other in silico tools, were used to explore clinicopathological correlations, protein expression, immune cell infiltration, and functional associations of YWHAG. ResultsYWHAG mRNA and protein expression were significantly upregulated in OSCC tumor tissues and OSCC cell lines compared to non-tumor tissues and normal cells (p < 0.001). High YWHAG expression significantly correlated with advanced tumor stage, higher grade, lymph node metastasis, and poor prognosis (p < 0.05). Functional analysis revealed that YWHAG is associated with pathways involved in aggressive cancer progression. YWHAG expression positively correlated with its target gene CTTN expression, which was also upregulated in OSCC and associated with poor prognosis (p < 0.05). ConclusionsStudy findings indicate that YWHAG may contribute to the progression of OSCC and could be a potential therapeutic target or prognostic biomarker. Further investigation is necessary to understand the underlying mechanisms and assess the clinical implications of YWHAG dysregulation in OSCC.

Low expression of interleukin-1 receptor antagonist correlates with poor prognosis via promoting proliferation and migration and inhibiting apoptosis in oral squamous cell carcinoma

BackgroundBiomarkers are biochemical indicators that can identify changes in the structure or function of systems, organs, or cells and can be used to monitor a wide range of biological processes, including cancer. Interleukin-1 receptor antagonist (IL1RA) is an important inflammatory suppressor gene and tumor biomarker. The goal of this study was to investigate the expression of IL1RA, its probable carcinogenic activity, and its diagnostic targets in oral squamous cell carcinoma (OSCC). ResultsWe discovered that IL1RA was expressed at a low level in OSCC tumor tissues compared to normal epithelial tissues and that the expression declined gradually from epithelial hyperplasia through dysplasia to carcinoma in situ and invasive OSCC. Low IL1RA expression was associated not only with poor survival but also with various clinicopathological markers such as increased infiltration, recurrence, and fatalities. Following cellular phenotyping investigations in OSCC cells overexpressing IL1RA, we discovered that recovering IL1RA expression decreased OSCC cell proliferation, migration, and increased apoptosis. ConclusionsIn summary, our investigation highlighted the possible involvement of low-expression IL1RA in OSCC cells in promoting invasive as well as metastatic and inhibiting apoptosis, as well as the efficacy of IL1RA-focused monitoring in the early detection and treatment of OSCC.

NFE2L1 restrains ferroptosis by transcriptionally regulating HJURP and participates in the progress of oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is a common head and neck malignancy with increasing mortality and high recurrence. In this work, we aim to explore the functional role of NFE2 like bZIP transcription factor 1 (NFE2L1) in OSCC progression. Based on databases analysis, we found that NFE2L1 was overexpressed in OSCC tumor tissues, and elevated NFE2L1 level induced poor prognosis of OSCC patients. Our results showed that NFE2L1 is upregulated in OSCC cells and overexpression of NFE2L1 promotes cell proliferation, and reduces the sensitivity of OSCC cells to erastin-induced ferroptosis. NFE2L1 upregulation decreased the levels of Fe2+, lipid reactive oxygen species and content of malondialdehyde, and increased the level of the key negative regulator of ferroptosis, GPX4 and SLC7A11. In NFE2L1 suppressed cells, these trends were reversed. Further results of dual luciferase reporter and chromatin immunoprecipitation assays confirmed that NFE2L1 could bind to the promoter of Holliday junction recognition protein (HJURP) to increase the transcriptional activity of HJURP, thus upregulating its expression. Inhibition of HJURP attenuated the proliferation and ferroptosis inhibition in NFE2L1 upregulated cells. In vivo tumorigenicity assay further proved that NFE2L1 promotes OSCC tumor growth. In summary, NFE2L1 restrains ferroptosis by transcriptionally regulating HJURP and participates in the progress of OSCC. Thus, NFE2L1 plays a key role in OSCC development and may be a promising therapeutic target for OSCC.

IL-1RA promotes oral squamous cell carcinoma malignancy through mitochondrial metabolism-mediated EGFR/JNK/SOX2 pathway

BackgroundInterleukin-1 receptor antagonist (IL-1RA), a member of the IL-1 family, has diverse roles in cancer development. However, the role of IL-1RA in oral squamous cell carcinoma (OSCC), in particular the underlying mechanisms, remains to be elucidated.MethodsTumor tissues from OSCC patients were assessed for protein expression by immunohistochemistry. Patient survival was evaluated by Kaplan–Meier curve analysis. Impact of differential IL-1RA expression on cultured OSCC cell lines was assessed in vitro by clonogenic survival, tumorsphere formation, soft agar colony formation, and transwell cell migration and invasion assays. Oxygen consumption rate was measured by Seahorse analyzer or multi-mode plate reader. PCR array was applied to screen human cancer stem cell-related genes, proteome array for phosphorylation status of kinases, and Western blot for protein expression in cultured cells. In vivo tumor growth was investigated by orthotopic xenograft in mice, and protein expression in xenograft tumors assessed by immunohistochemistry.ResultsClinical analysis revealed that elevated IL-1RA expression in OSCC tumor tissues was associated with increased tumor size and cancer stage, and reduced survival in the patient group receiving adjuvant radiotherapy compared to the patient group without adjuvant radiotherapy. In vitro data supported these observations, showing that overexpression of IL-1RA increased OSCC cell growth, migration/invasion abilities, and resistance to ionizing radiation, whereas knockdown of IL-1RA had largely the opposite effects. Additionally, we identified that EGFR/JNK activation and SOX2 expression were modulated by differential IL-1RA expression downstream of mitochondrial metabolism, with application of mitochondrial complex inhibitors suppressing these pathways. Furthermore, in vivo data revealed that treatment with cisplatin or metformin—a mitochondrial complex inhibitor and conventional therapy for type 2 diabetes—reduced IL-1RA-associated xenograft tumor growth as well as EGFR/JNK activation and SOX2 expression. This inhibitory effect was further augmented by combination treatment with cisplatin and metformin.ConclusionsThe current study suggests that IL-1RA promoted OSCC malignancy through mitochondrial metabolism-mediated EGFR/JNK activation and SOX2 expression. Inhibition of this mitochondrial metabolic pathway may present a potential therapeutic strategy in OSCC.

Cold Physical Plasma Toxicity in Breast and Oral Squamous Carcinoma In Vitro and in Patient-Derived Cancer Tissue Ex Vivo

Breast cancer (BC) and oral squamous cell carcinoma (OSCC) are among the most common types of cancer, but current clinical outcomes remain unsatisfactory. Available therapies have limitations in terms of efficacy and may also cause severe side effects. Cold physical plasma is a promising approach for selectively eliminating cancer cells while avoiding genotoxic effects on non-malignant cells. In this study, we investigated the potential of cold physical plasma as a therapeutic intervention for BC and OSCC through in vitro and ex vivo studies on toxicity. For the in vitro study, T-47 BC cells and SCC-4 and SCC-9 OSCC cell lines were used, and we found cold plasma to be toxic in a treatment time-dependent manner. Moreover, we investigated the safety of physical plasma therapy and found no genotoxic potential in plasma-treated human keratinocytes in vitro. Finally, for the first time, 20 BC and OSCC patient-derived tumor tissues were punch biopsied and ex vivo-exposed to cold physical plasmas to study responses in the tumor microenvironment TME). Cold physical plasma caused significant apoptosis in patient-derived BC and OSCC tumor tissues, and decreased the number of CD163+ cells (e.g., tumor-associated macrophages, TAM) in BC tissue plasma-treated ex vivo. Collectively, our findings motivate the investigation of cold physical plasma as a potential adjuvant treatment in oncology.

Curcumol Exerts Antitumor Effect via Inhibiting EGFR-Akt-Mcl-1 Signaling.

Dysfunction of epidermal growth factor receptor (EGFR) signaling plays a critical role in the tumorigenesis of oral squamous cell carcinoma (OSCC). In the present study, the data analysis results of immunohistochemistry and the TCGA database verified that the expression of EGFR is significantly upregulated in OSCC tumor tissues, and depletion of EGFR inhibits the growth of OSCC cells in vitro and in vivo. Moreover, these results showed that the natural compound, curcumol, exhibited a profound antitumor effect on OSCC cells. Western blotting, MTS, and immunofluorescent staining assays indicated that curcumol inhibited cell proliferation and induced intrinsic apoptosis in OSCC cells via downregulating myeloid cell leukemia 1 (Mcl-1). A mechanistic study revealed that curcumol inhibited the EGFR-Akt signal pathway, which activated GSK-3[Formula: see text]-mediated Mcl-1 phosphorylation. Further research showed that curcumol-induced Mcl-1 Ser159 phosphorylation is required to disrupt the interaction between deubiquitinase JOSD1 and Mcl-1 and eventually induce Mcl-1 ubiquitination and degradation. In addition, curcumol administration can effectively inhibit CAL27 and SCC25 xenograft tumor growth and is well-tolerated in vivo. Finally, we demonstrated that Mcl-1 is upregulated and positively correlates with p-EGFR and p-Akt in OSCC tumor tissues. Collectively, the present results provide new insights into the antitumor mechanism of curcumol, identifying it as an attractive therapeutic agent that reduces Mcl-1 expression and inhibits OSCC growth. Targeting EGFR/Akt/Mcl-1 signaling could be a promising option in the clinical treatment of OSCC.

MICRORNA-31 AS A POTENTIAL THERAPEUTIC BIOMARKER FORORAL SQUAMOUS CELL CARCINOMA: CURRENT EVIDENCE AND FUTURE PROSPECTS.

Dear Editor,&#x0D; Cancer is a foremost death cause in each country and a substantial hindrance to improving life expectancy, accounting for more than 10 million fatalities in 2020, or around one in every six fatalities [1]. Oral cancer is among the leading causes of cancer-related mortality in developing countries. Oral squamous cell carcinoma (OSCC) is a widespread type of malignancy associated with tobacco usage and human papilloma virus infection. The majority of people are diagnosed with cancer at an advanced stage, the 5-year survival rate for OSCC patients is only around 50%. Despite biological and technological advances, in recent decades, the prognosis for OSCC has not improved, and its occurrence has increased. Identification of biomarkers that can be utilized to establish an early diagnosis or predict tumor growth is enabled by determining which molecular pathways are disrupted [2].&#x0D; MicroRNAs, which can serve as both oncogenes and tumor-inhibiting factors, are misaligned in a wide range of cancers [3]. These are short, noncoding RNAs that affect protein expression following transcription at the post-transcriptional level. MicroRNAs play a vital role in proliferation, differentiation, apoptosis, immune response, and angiogenesis, among other things in the pathogenesis of cancer. Multiple researchers have documented that specific microRNAs are frequently down regulated in cancers, implying that they operate as tumor suppressors by targeting many oncogenes. According to research conducted by O’Brien et al, altering levels of microRNAs expression can improve chemotherapeutic efficacy [4]. In recent decades, several researches have linked metastasis, survival, and recurrence of OSCC patients to miRNA expression [5].&#x0D; MicroRNA-31, a gene on chromosome 9p21.3, was one of the first mammalian microRNAs discovered. Several studies have been conducted to evaluate the functions of miR-31 in carcinogenesis and the progression of OSCC. A prior clinical investigation conducted by Liu et al. [6] revealed that miR-31 levels in plasma were considerably increased in patients with OSCC when compared to age and gender-matched control participants. Several studies show that miR-31 performs a role in cancer etiology and aggressiveness via altering target genes. According to reports, miR-31 regulates a number of genes, including fibronectin type III domain containing 5, special AT-rich sequence-binding protein-2, large tumor suppressor kinase 2 (LATS2), tensin 1, AT-rich interaction domain 1A, and hypoxia-inducible factor-1 [7]. The concentration of miR-31 expression in serum, urine, saliva and organ tissue can be utilized as a diagnostic and predictive biomarker for a variety of malignancies [8].&#x0D; A recent investigation by Chou et al. [9] found that miR-31 levels were significantly raised in OSCC cells and tumor tissues, and that the miR-31 gene locus was necessary to initiate oncogenesis in OSCC. Upregulation of miR-31 contributes to the formation of OSCC by interacting with certain genes and signaling pathways that impact cancer cell cycle, epithelial-mesenchymal transition and cell proliferation. miR-31 forms a complex network with direct target genes (such as RHOA, FIH, ACOX1, VEGF, SIRT3, LATS2, KANK1, and NUMB) and initiates several signaling pathways including the ERK-MMP9 cascade, the Hippo pathway, Wnt signaling, and the MCT1/MCT4 regulatory cascade [10]. MiR-31 interacts with a number of proteins and pathways that are crucial in OSCC and it is overexpressed in plasma, saliva, and OSCC tumor tissue. However, more research is needed to fully comprehend the molecular mechanisms by which miR-31 drives OSCC malignancy, paving the way for the development of miR-31 based diagnostic, prognostic, and predictive biomarkers for OSCC.

Stabilization of MCL-1 by E3 ligase TRAF4 confers radioresistance

The E3 ligase TNF receptor-associated factor 4 (TRAF4) is frequently overexpressed and closely related to poor prognosis in human malignancies. However, its effect on carcinogenesis and radiosensitivity in oral squamous cell carcinoma (OSCC) remains unclear. The present study found that TRAF4 was significantly upregulated in primary and relapsed OSCC tumor tissues. Depletion of TRAF4 markedly improved the sensitivity of OSCC cells to irradiation (IR) treatment, showing that tumor cell proliferation, colony formation and xenograft tumor growth were reduced. Mechanistically, IR promoted the interaction between TRAF4 and Akt to induce Akt K63-mediated ubiquitination and activation. TRAF4 knockout inhibited the phosphorylation of Akt and upregulated GSK3β activity, resulting in increased myeloid cell leukemia-1 (MCL-1) S159 phosphorylation, which disrupted the interaction of MCL-1 with Josephin domain containing 1 (JOSD1), and ultimately induced MCL-1 ubiquitination and degradation. Moreover, TRAF4 was positively correlated with MCL-1 in primary and in radiotherapy-treated, relapsed tumor tissues. An MCL-1 inhibitor overcame radioresistance in vitro and in vivo. Altogether, the present findings suggest that TRAF4 confers radioresistance in OSCC by stabilizing MCL-1 through Akt signaling, and that targeting TRAF4 may be a promising therapeutic strategy to overcome radioresistance in OSCC.

Localization of Fusobacterium nucleatum in oral squamous cell carcinoma and its possible directly interacting protein molecules: A case series.

While 15 to 20% of cancers are associated with microbial infection, the relationship between oral microorganisms and oral squamous cell carcinoma (OSCC) remains unclear. The location of bacteria in a tumor is closely related to its carcinogenic mechanism. The aim of this study was to analyse bacterial diversity in clinical OSCC tissue samples and tumor distant normal tissues, locate target bacteria, and search for proteins that may interact with target bacteria. The 16S rDNA method was used to analyse bacterial diversity in clinical OSCC tissue samples and tumor distant normal tissues. Correlations between Fusobacterium abundance and clinicopathological characteristics were analysed using the χ2 test. The position of target bacteria was analysed by fluorescence in situ hybridization (FISH), and the expression of CK, CD31, CD45, CD68, cyclin D1, β-catenin, E-cadherin, NF-κB, and HIF-1α was analysed by immunohistochemistry (IHC) in OSCC tumor tissues and tumor distant normal tissues. The 16S rDNA results showed that the detected amount of Fusobacterium in OSCC tumor tissues was significantly larger than that in tumor distant normal tissues. High expression of Fusobacterium was significantly correlated with the lifestyle-related oral risk habits, including smoking (p=0.036) and alcohol consumption (p=0.022), but did not correlate with patient sex, age, tumor laterality, tumor size, grade or TNM stage. Fusobacterium nucleatum was enriched in tumor stroma, where CD31+ blood vessels and inflammatory cells (including CD45+ leukocytes and CD68+ macrophages) were densely distributed. Cyclin D1 was mainly expressed in the nucleus of tumor cells. β-catenin was expressed in the tumor cell membrane and was positively expressed in tumor interstitial vascular endothelial cells. E-cadherin was mainly expressed in tumor cell membranes. NF-κB was positively expressed in the cytoplasm of tumor cells, tumor interstitial cells and myo-fibrocytes. HIF-1α was mainly expressed in the cytoplasm of tumor interstitial cells. HIF-1α was highly expressed where Fusobacterium nucleatum was densely distributed. According to our study, the detected amount of Fusobacterium in OSCC tumor tissues was significantly larger than that in tumor distant normal tissues, and Fusobacterium nucleatum might aggravate inflammation and hypoxia by interacting with NF-κB and HIF-1α in OSCC.

MiR-125b Promotes the Proliferation, Migration and Invasion of Oral Squamous Cell Carcinoma (OSCC)

miR-125b is involved in several tumors. However, miR-125b’s role in oral squamous cell carcinoma (OSCC) is unclear. Tumor tissues and oral normal mucosa tissues of OSCC patients were collected to measure miR-125b level. Oral cancer Tca8113 cells were separated into control group, miR-125b inhibitor group, and miR-125b mimics group, followed by measuring miR-125b level by real time PCR, cell survival, migration and invasion, PI3K/mTOR signaling protein level by Western blot. miR-125b was upregulated in OSCC tumor tissues and related to clinical/TNM stage, metastasis and overall survival (P &lt; 0.05). miR-125b overexpression significantly promoted tumor cell behaviors and increased PI3K/mTOR phosphorylation (P &lt; 0.05); while inhibiting miR-125b expression significantly inhibited tumor cell biological behaviors, and decreased PI3K/mTOR phosphorylation (P &lt; 0.05). miR-125b level is increased in OSCC tumor tissues, which is related to clinicopathological characteristics. miR-125b overexpression promotes OSCC cell behaviors by regulating PI3K/mTOR signaling.

Identification of Biological Functions and Prognostic Value of NNMT in Oral Squamous Cell Carcinoma.

Background: Nicotinamide N-methyltransferase (NNMT) is a metabolic enzyme that catalyzes the methylation of nicotinamide (NAM) to generate 1-methyl nicotinamide (MNAM). Although previous studies have shown that NNMT is frequently dysregulated to promote the onset and progression of many malignancies, its expression profile, prognostic value and function in oral squamous cell carcinoma (OSCC) are still unknown. Methods: We used untargeted metabolomics based on mass spectrometry to analyze potential metabolite differences between tumors and matched adjacent normal tissues in 40 OSCC patients. Immunohistochemistry (IHC) was used to analyze the NNMT expression profile in OSCC, and the diagnostic and prognostic values of NNMT were evaluated. Next, qPCR and Western blot were used to compare the expression of NNMT in five OSCC cell lines. Stable transfected cell lines were constructed, and functional experiments were carried out to elucidate the effects of NNMT on the proliferation and migration of OSCC cells. Finally, gene set enrichment analysis (GSEA) was performed using The Cancer Genome Atlas (TCGA) data to investigate the potential functional mechanisms of NNMT in OSCC. Results: We found that the nicotinamide metabolic pathway was abnormally activated in OSCC tumor tissues compared with normal tissues. NNMT was expressed ubiquitously in tumor cells (TCs) and fibroblast-like cells (FLCs) but was absent in tumor-infiltrating lymphocytes (TILs). OSCC patients with highly expressed NNMT in TCs had higher risk of lymph node metastasis and showed a worse pattern of invasion (POI). Moreover, patients with highly expressed NNMT were also susceptible to postoperative recurrence. Highly expressed NNMT can independently predict shorter disease-free survival and recurrence-free survival. Functionally, we demonstrated that the ectopic expression of NNMT promoted OSCC tumor cell proliferation and migration in vitro. Conversely, silencing exerted significantly opposite effects in vitro. In addition, GSEA showed that highly expressed NNMT was mainly enriched in the epithelial–mesenchymal transformation (EMT) pathway, which displayed a significant positive correlation with the six classic EMT markers. Conclusions: Our study uncovered that NNMT may be a critical regulator of EMT in OSCC and may serve as a prognostic biomarker for OSCC patients. These findings might provide novel insights for future research in NNMT-targeted OSCC metastasis and recurrence therapy.

CD44 Mediates Oral Squamous Cell Carcinoma-Promoting Activity of MRE11 via AKT Signaling.

Oral cancer is one of the highest-incidence malignancies worldwide, with the occurrence of oral squamous cell carcinoma (OSCC) being the most frequently diagnosed form. A barrier for oral cancer management may arise from tumor cells that possess properties of cancer stemness, which has been recognized as a crucial factor in tumor recurrence and metastasis. As such, understanding the molecular mechanisms underlying these tumor cells may provide insights for improving cancer treatment. MRE11 is the core protein of the RAD50/MRE11/NBS1 complex with a primary role in DNA damage repair, and it has been diversely associated with tumor development including OSCC. In this study, we aimed to investigate the engagement of CD44, a cancer stemness marker functioning in the control of cell growth and motility, in OSCC malignancy under the influence of MRE11. We found that overexpression of MRE11 enhanced CD44 expression and tumorsphere formation in OSCC cells, whereas knockdown of MRE11 reduced these phenomena. In addition, the MRE11-promoted tumorsphere formation or cell migration ability was compromised in OSCC cells carrying siRNA that targets CD44, as was the MRE11-promoted AKT phosphorylation. These were further supported by analyzing clinical samples, where higher CD44 expression was associated with lymph node metastasis. Additionally, a positive correlation between the expression of MRE11 and CD44, or that of CD44 and phosphorylated AKT, was observed in OSCC tumor tissues. Finally, the expression of CD44 was found to be higher in the metastatic lung nodules from mice receiving tail vein-injection with MRE11-overexpressing OSCC cells compared with control mice, and a positive correlation between CD44 and phosphorylated AKT was also observed in these metastatic lung nodules. Altogether, our current study revealed a previously unidentified mechanism linking CD44 and AKT in MRE11-promoted OSCC malignancy, which may shed light to the development of novel therapeutic strategies in consideration of this new pathway in OSCC.

MiR-186-5p inhibits the progression of oral squamous cell carcinoma by targeting ITGA6 to impair the activity of the PI3K/AKT pathway.

microRNAs (miRNAs) are pivotal regulators of multiple biological processes. miR-186-5p functions as a tumor suppressor in a variety of cancers and promotes the malignant proliferation of oral squamous cell carcinoma (OSCC). This study aimed to clarify the role and regulatory mechanism of miR-186-5p in OSCC. The levels of miR-186-5p and integrin subunit alpha 6 (ITGA6) were investigated in clinical specimens and OSCC cell lines by reverse transcription-quantitative polymerase chain reaction. The effects of miR-186-5p and ITGA6 on the cell migration, proliferation, and phosphatidylinositol 3-kinase (PI3K)/serine-threonine kinase (AKT) pathway activity were evaluated by transwell assay, cell counting kit 8 assay, and western blotting, respectively. A xenograft model was used to analyze the effect of miR-186-5p on tumor growth. Bioinformatic analyses were conducted to identify the putative targets of miR-186-5p in OSCC. Decreased miR-186-5p expression levels were observed in OSCC tumor tissues and cell lines. The overexpression of miR-186-5p suppressed the proliferation and migration of OSCC cells, and weakened the phosphorylation of PI3K and AKT. Moreover, the overexpression of miR-186-5p in xenograft tumor models impedes tumor growth. miR-186-5p is bound to ITGA6 and negatively related to ITGA6 expression in tumor tissues. The forced expression of ITGA6 promoted OSCC cell proliferation and migration and enhanced the phosphorylation levels of PI3K and AKT, while additional miR-186-5p enrichment partly abolished these effects. miR-186-5p binds to ITGA6 to impair the activity of the PI3K/AKT signaling pathway, thereby blocking the development of OSCC. This study provides insight to understand the pathogenesis of OSCC.

Circular RNA mitochondrial translation optimization 1 homologue (CircMTO1) induced by zinc finger protein 460 (ZNF460) promotes oral squamous cell carcinoma progression through the microRNA miR-320a / alpha thalassemia/mental retardation, X-linked (ATRX) axis

ABSTRACT Oral squamous cell carcinoma (OSCC) is one of the most common cancer types of head and neck cancer, accounting for 95% of all cases. However, the mechanisms underlying the pathogenesis of OSCC remain unclear. Circular RNA (CircRNA) has been extensively studied in the past decades and is a promising direction for the development of OSCC therapeutic targets. In this study, we aimed to investigate the role of circMTO1 in OSCC progression. First, we validated the characterization and expression of circMTO1 in OSCC. It was found that circMTO1 was upregulated in OSCC tumor tissues and cells. Subsequently, we conducted biological experiments. It was found that circMTO1 knockdown inhibited OSCC cell proliferation, migration, and invasion. Furthermore, we conducted a series of experiments to elucidate the underlying mechanisms. A novel circMTO1/miR-320a/ATRX axis was identified. Our results suggest that circMTO1 modulates ATRX expression to accelerate OSCC progression by sponging miR-320a. Moreover, we found that circMTO1 expression in OSCC was transcriptionally regulated by Zinc Finger Protein 460 (ZNF460). Our study showed a novel ZNF460/circMTO1/miR-320a/ATRX signaling in OSCC development.

Identification and Validation of PLOD2 as an Adverse Prognostic Biomarker for Oral Squamous Cell Carcinoma.

Background: Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2), a key enzyme that catalyzes the hydroxylation of lysine, plays a crucial role in the progression of several solid tumors. However, its spatial expression profile and prognostic significance in oral squamous cell carcinoma (OSCC) have not been revealed. Materials: Mass spectrometry was used to explore amino acid perturbations between OSCC tumor tissues and paired normal tissues of 28 patients. Then, PLOD2 mRNA and protein levels were assessed using several public databases and 18 pairs of OSCC patients’ tissues. Additionally, PLOD2 spatial expression profiles were investigated in 100 OSCC patients by immunohistochemistry and its diagnostic and prognostic values were also evaluated. Lastly, gene set enrichment analysis (GSEA) was used to investigate the potential functions of PLOD2 in OSCC. Results: Lysine was significantly elevated in OSCC tissues and could effectively distinguish tumor from normal tissues (AUC = 0.859, p = 0.0035). PLOD2 mRNA and protein levels were highly increased in tumor tissues of head and neck squamous cell carcinoma (HNSCC) (p < 0.001) and OSCC compared with those in nontumor tissues (p < 0.001). Histopathologically, PLOD2 was ubiquitously expressed in tumor cells (TCs) and fibroblast-like cells (FLCs) of OSCC patients but absent in tumor-infiltrating lymphocytes (TILs). Patients with highly expressed PLOD2 in TCs (PLOD2TCs) and FLCs (PLOD2FLCs) showed poor differentiation, a worse pattern of invasion (WPOI) and more lymph node metastasis (LNM), contributing to higher postoperative metastasis risk and poor survival time. However, PLOD2FLCs rather than PLOD2TCs was an independent risk factor for survival outcomes in OSCC patients. Molecularly, GSEA demonstrated highly expressed PLOD2 was mainly enriched in epithelial–mesenchymal transformation (EMT), TGF-beta signaling and hypoxia pathway, which are associated with poor clinical outcomes of OSCC patients. Conclusions: PLOD2 was a poor prognostic biomarker for OSCC patients and may affect the metastasis of OSCC through EMT pathway. These findings might shed novel sights for future research in PLOD2 targeted OSCC therapy.

Bone Marrow Mesenchymal Stem Cells (BMSCs) with High Expression miR-155 Affect the Proliferation and Metastasis of Oral Squamous Cell Carcinoma by Regulating Phosphatase and Tensin Homolog 12 (PTEN12)

Oral squamous cell carcinoma (OSCC) had the poor prognosis. miR-155 was involved in some diseases. However, whether BMSCs with high expression miR-155 affect the proliferation and metastasis of OSCC is unclear. Our study aims to assess BMSCs’ effect on OSCC cells. miR-155 level in OSCC tumor tissues was analyzed. BMSCs were transfected with miR-155 followed by analysis of cell proliferation by MTT assay, cell apoptosis and migration, and MMP-9 level by ELISA and PTEN12 level. In the tumor tissue, miR-155 level was significantly increased (P &lt;0.05). Co-culture of BMSCs with high expression miR-155 with OSCC cells could significantly promote OSCC cell proliferation and reduced cell apoptotic activity, increased cell migration and MMP-9 secretion as well as downregualted PTEN12 expression (P &lt;0.05). In conclusion, miR-155 was increased in the OSCC patients and BMSCs of high expression miR-155 could promote the proliferation and metastasis of OSCC by regulating PTEN12.

LINC01123 is associated with prognosis of oral squamous cell carcinoma and involved in tumor progression by sponging miR-34a-5p

Oral squamous cell carcinoma (OSCC) is a malignant tumor. This study aimed to investigate the role of a long noncoding RNA (lncRNA), LINC01123, in OSCC prognosis and progression and to explore the underlying mechanisms. OSCC tissues were collected from 102 patients, and 4 OSCC cell lines were analyzed. The expression levels of LINC01123 and miR-34a-5p were estimated using quantitative real-time polymerase chain reaction (qRT-PCR). Cell counting kit-8 (CCK-8) and Transwell assays were used to assess the proliferation, migration, and invasion of OSCC cells. Kaplan-Meier survival analysis was used to analyze the prognostic value of LINC01123 in OSCC. The analysis results showed that LINC01123 was overexpressed in OSCC tumor tissues; also, the prognosis of patients with OSCC with high LINC01123 expression levels was poor. The knockdown of LINC01123 inhibited the proliferation, migration, and invasion of OCSS cells. MiR-34a-5p was a target of LINC01123, and its inhibitor could reverse the effect of silenced LINC01123 on the progression of OSCC. Highly expressed LINC01123 was associated with poor prognosis of OSCC and regulated OSCC cell proliferation, invasion, and migration by sponging miR-34a-5p. Therefore, the LINC01123/miR-34a-5p axis may provide new ideas for the prognosis and treatment of OSCC.

Circular RNA circFOXO3 regulates KDM2A by targeting miR-214 to promote tumor growth and metastasis in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is a pathological type of oral cancer, which accounts for over 90% of oral cancers. It has been widely shown that circRNA is involved in the regulation of multiple malignant oral diseases including OSCC. However, the mechanism underlying how circRNA regulates OSCC is still not clearly elucidated. In this article, we report circFOXO3 promotes tumor growth and invasion of OSCC by targeting miR‐214 which specifically degrades the lysine demethylase 2A (KDM2A). CircRNA sequencing was conducted in OSCC tumor and tumor‐side tissues, and the expression of circFOXO3 is found to be markedly increased in tumor tissues. CircFOXO3 is also highly expressed in several OSCC cell lines compared with human oral keratinocytes. Transwell assay and colony formation showed that knockdown of circFOXO3 prevents the invasion and proliferation of oral cancer cells. Via bioinformatic research, miR‐214 was found to be the target of circFOXO3 and correlate well with circFOXO3 both in vitro and in vivo. KDM2A was then validated by database analysis and luciferase assay to be the direct target of miR‐214. KDM2A helps to promote tumor invasiveness and proliferation of OSCC. Collectively, our results proved that circFOXO3 sponges miR‐214 to up‐regulate the expression of KDM2A, thus promotes tumor progression in OSCC.

Circ_0001461 promotes oral squamous cell carcinoma progression through miR-145/TLR4/NF-κB axis

Circular RNAs (circRNAs) have been widely reported to participate in progression of various cancers, including oral cancer. Previous study showed circ_0001461 was aberrantly expressed in oral squamous cell carcinoma (OSCC), while its role in tumorigenesis of OSCC remains largely unclear. In this study, we confirmed that circ_0001461 was highly expressed in OSCC cell lines and tumor tissues. Knocking down of circ_0001461 suppressed cell proliferation, migration and invasion in vitro, and repress xenograft tumor growth in vivo. Mechanistically, we found circ_0001461 regulates OSCC cell proliferation, migration and invasion through sponging miR-145. Furthermore, circ_0001461 promotes the resistance of TNF-α-induced apoptosis of OSCC cells by modulating miR-145/TLR4/NF-κB pathway. In general, our study demonstrated a novel regulatory mechanism that circ_0001461/miR-145/TLR4/NF-κB axis modulates oral squamous cell carcinoma progression.

NOTCH1 mutations as prognostic marker in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common malignancy of the oral cavity with poor prognosis. The dysregulation of Notch signaling pathway has been implicated in the OSCC tumorigenesis. However, the clinical implication of NOTCH1 mutation status in OSCC remains unelucidated. We extracted the NOTCH1 gene mutations from a whole exome sequencing dataset of 168 frozen OSCC tumor specimens and validated these NOTCH1 gene mutations by Sanger sequencing. We also assessed these NOTCH1 gene mutations and its pathological significance in our OSCC tumor tissues using immunohistochemistry. Univariate and multivariate analyses were also used to determine whether the association between NOTCH1 mutation status and prognostic factors was independent of other parameters. In this study, we have identified 44 (26.19 %) NOTCH1 gene mutations from a whole-exome sequencing of 168 OSCC formalin-fixed, paraffin-embedded (FFPE) tissue specimen. These mutations distributed in different NOTCH1 function domains, including the EGF-like repeats region, negative regulatory region, and Ankyrin repeats region. The immunohistochemical staining analysis revealed that NOTCH1 expression was increased in oral cancer tissues. In addition, of the 43 OSCC tumors with NOTCH1 mutations, we observed that the majority were negative for NOTCH1 intracellular domain 1 (NICD1) staining (76.74 %), and 10 tumors were positive for NICD1 staining (23.26 %). In conclusion, our study suggested that NOTCH1 expression is associated with the progression of OSCC. We also demonstrated that presence of a mutated NOTCH1 gene will help prognostic stratification in OSCC when combined with other clinicopathologic parameters.