KLF7 regulates super-enhancer-driven IGF2BP2 overexpression to promote the progression of head and neck squamous cell carcinoma.

BACKGROUND: Head and neck squamous carcinoma (HNSCC) is known for its high aggressiveness and susceptibility to cervical lymph node metastasis, which greatly contributes to its poor prognosis. During tumorigenesis, many types of cancer cells acquire oncogenic super-enhancers (SEs) that drive the overexpression of oncogenes, thereby maintaining malignant progression. This study aimed to identify and validate the role of oncogenic SE-associated genes in the malignant progression of HNSCC. METHODS: We identified HNSCC cell-specific SE-associated genes through H3K27Ac ChIP-seq and overlapped them with HNSCC-associated genes obtained from The Cancer Genome Atlas (TCGA) dataset and Gene Expression Omnibus (GEO) datasets using weighted gene coexpression network analysis (WGCNA) to identify hub genes. The expression of IGF2BP2 and KLF7 in HNSCC was detected using clinical samples. To determine the biological role of IGF2BP2, we performed CCK-8, colony formation assay, Transwell migration assay, invasion assay, and orthotopic xenograft model experiments. Furthermore, we utilized a CRISPR/Cas9 gene-editing system, small-molecule inhibitors, ChIP-qPCR, and dual-luciferase reporter assays to investigate the molecular mechanisms of IGF2BP2 and its upstream transcription factors. RESULTS: Our study identified IGF2BP2 as a hub SE-associated gene that exhibited aberrant expression in HNSCC tissues. Increased expression of IGF2BP2 was observed to be linked with malignant progression and unfavorable prognosis in HNSCC patients. Both in vitro and in vivo experiments confirmed that IGF2BP2 promotes the tumorigenicity and metastasis of HNSCC by promoting cell proliferation, migration, and invasion. Mechanistically, the IGF2BP2-SE region displayed enrichment for H3K27Ac, BRD4, and MED1, which led to the inhibition of IGF2BP2 transcription and expression through deactivation of the SE-associated transcriptional program. Additionally, KLF7 was found to induce the transcription of IGF2BP2 and directly bind to its promoter and SE regions. Moreover, the abundance of KLF7 exhibited a positive correlation with the abundance of IGF2BP2 in HNSCC. Patients with high expression of both KLF7 and IGF2BP2 showed poorer prognosis. Lastly, we demonstrated that the small molecule inhibitor JQ1, targeting BRD4, attenuated the proliferation and metastatic abilities of HNSCC cells. CONCLUSIONS: Our study reveals the critical role of IGF2BP2 overexpression mediated by SE and KLF7 in promoting HNSCC progression. Targeting SE-associated transcriptional programs may represent a potential therapeutic strategy in managing HNSCC.

FTO Sensitizes Oral Squamous Cell Carcinoma to Ferroptosis via Suppressing ACSL3 and GPX4.

Ferroptosis is a newly established form of regulated cell death characterized by intracellular lipid peroxidation and iron accumulation that may be a promising cancer treatment strategy. However, the function and therapeutic value of ferroptosis in oral squamous cell carcinoma (OSCC) remain inadequately understood. In the present study, we investigated the biological role of the fat mass and obesity-associated gene (FTO) in ferroptosis in the context of OSCC. We found that OSCC had greater potential for ferroptosis, and FTO is associated with ferroptosis. Furthermore, higher FTO expression sensitized OSCC cells to ferroptosis in vitro and in vivo. Mechanistically, FTO suppressed the expression of anti-ferroptotic factors, acyl-CoA synthetase long-chain family member 3 (ACSL3) and glutathione peroxidase 4 (GPX4), by demethylating the m6A modification on the mRNA of ACSL3 and GPX4 and decreasing their stability. Taken together, our findings revealed that FTO promotes ferroptosis through ACSL3 and GPX4 regulation. Thus, ferroptosis activation in OSCC with high FTO levels may serve as a potential therapeutic target.

Identification of CKS2 as a novel prognostic biomarker and potential therapeutic target for oral squamous cell carcinoma.

Background: The cyclin-dependent kinase subunit 2 (CKS2) is recognized to have a substantial impact on the pathogenesis and advancement of several malignant neoplasms. Nevertheless, its biological function and prognostic significance in oral squamous cell carcinoma (OSCC) have yet to be thoroughly investigated. Our primary objective was to clarify the contribution of CKS2 in the progression and prognosis of OSCC. Methods: We first conducted a thorough examination of online databases to investigate the expression of CKS2, and subsequently corroborated our discoveries by analyzing clinical specimens that we collected. According to the clinicopathological data, we then explored the prognostic significance of CKS2. Furthermore, we predicted the role of CKS2 in OSCC progression by employing weighted gene co-expression network analysis (WGCNA) in conjunction with functional enrichment analysis. We conducted functional experiments in vitro to confirm our speculations. Additionally, we explored other potential functions of CKS2 in immune infiltration, tumor mutation burden (TMB), and drug sensitivity. Finally, we established and validated a nomogram that effectively integrated CKS2-related genes and other relevant clinical factors. Results: Our findings indicated a significant upregulation of CKS2 expression in OSCC tissues compared to normal groups, which was positively associated with poor clinical outcomes. We also predicted and validated the role of CKS2 in promoting proliferation by regulating the cell cycle. Additionally, its upregulation was significantly correlated to enhanced immune cell infiltration, high TMB, and increased sensitivity of anti-tumor agents. Following verification, the nomogram was conducted to quantify an individual's survival probability. Conclusions: In general, our study indicates that CKS2 is a novel prognostic biomarker and potential therapeutic target in OSCC.

METTL14 inhibits malignant progression of oral squamous cell carcinoma by targeting the autophagy-related gene RB1CC1 in an m6A-IGF2BP2-dependent manner.

N6-methyladenosine (m6A) plays crucial roles in tumorigenesis and autophagy. However, the underlying mechanisms mediated by m6A and autophagy in the malignant progression of oral squamous cell carcinoma (OSCC) remain unclear. In the present study, we revealed that down-regulated expression of METTL14 was correlated with advanced clinicopathological characteristics and poor prognosis in OSCC. METTL14 knockdown significantly inhibited autophagy and facilitated malignant progression in vitro, and promoted tumor growth and metastasis in vivo. A cell model of rapamycin-induced autophagy was established to identify RB1CC1 as a potential target gene involved in m6A-regulated autophagy in OSCC, through RNA sequencing and methylated RNA immunoprecipitation sequencing (meRIP-seq) analysis. Mechanistically, we confirmed that METTL14 posttranscriptionally enhanced RB1CC1 expression in an m6A-IGF2BP2-dependent manner, thereby affecting autophagy and progression in OSCC, through methylated RNA immunoprecipitation qRT-PCR (meRIP-qPCR), RNA stability assays, mutagenesis assays and dual-luciferase reporter. Collectively, our findings demonstrated that METTL14 serves as an OSCC suppressor by regulating the autophagy-related gene RB1CC1 through m6A modification, which may provide a new insight for the diagnosis and therapy of OSCC.

Integrative Analysis of N6-Methyladenosine-Related Enhancer RNAs Identifies Distinct Prognosis and Tumor Immune Micro-Environment Patterns in Head and Neck Squamous Cell Carcinoma.

At present, the prognostic value of N6-methyladenosine (m6A)-related enhancer RNAs (eRNAs) for head and neck squamous cell carcinoma (HNSCC) still remains unclear. Our study aims to explore the prognostic value of m6A-related eRNAs in HNSCC patients and their potential significance in immune infiltration and immunotherapy. We constructed a 5 m6A-related eRNAs risk model from The Cancer Genome Atlas (TCGA) HNSCC dataset, using univariate and multivariate Cox and least absolute shrinkage and selection operator (LASSO) regression analysis. Based on the SRAMP website and in vitro experiments, it was verified that these 5 m6A-related eRNAs had m6A sites, the expression of which was regulated by corresponding m6A regulators. Moreover, we constructed a nomogram base on 5 m6A-related eRNAs and confirmed the consistency and robustness of an internal TCGA testing set. Further analysis found that the risk score was positively associated with low overall survival (OS), tumor cell metastasis, metabolic reprogramming, low immune surveillance, lower expression of immune-related genes, and higher expression of targeted genes. Finally, we verified that silencing MIR4435-2HG inhibited HNSCC cell migration and invasion. This study contributes to the understanding of the characteristics of m6A-related eRNAs in HNSCC and provides a reference for effective immunotherapy and targeted therapy.

Clinical Prediction Nomograms to Assess Overall Survival and Disease-Specific Survival of Patients with Salivary Gland Adenoid Cystic Carcinoma.

Aim: Salivary gland adenoid cystic carcinoma (SACC) is the second highest incidence of malignant salivary gland tumor. The purpose of this study was to establish nomograms combined with SACC patients based on the Surveillance, Epidemiology, and End Results (SEER) database. Methods: Patients with SACC were included in the SEER∗Stat Database from 2004 to 2016. The least absolute shrinkage and selection operator (LASSO) Cox regression analysis was applied to filter potential prognostic clinical variables. Multivariate analysis from the Cox proportional hazards model was performed to determine the independent prognostic factors on overall survival (OS) and disease-specific survival (DSS), applied to develop nomograms. The Schönfeld residual test verified the proportional hazard assumption. The discrimination and consistency of nomograms was assessed and validated according to concordance index (C-index), receiver operating characteristic (ROC) curves, and calibration curves using an internal 1,000 times bootstrap resampling. The nomogram's net clinical benefit was assessed through decision curve analysis (DCA). Results: A total of 658 patients with SACC were included. Age, T stage, N stage, M stage, histologic grade, and surgery were independent prognostic factors for OS and DSS. Based on these independent prognostic factors, nomograms were developed to predict 3-, 5-, and 10-year OS and DSS. In the validation of 1,000 times bootstrap resampling, the C-index and ROC curves had good discriminatory ability. The calibration curves indicated excellent consistency between the predicted and actual survival results in the nomograms. The DCA curves demonstrated that the nomograms had good clinical benefit and were superior to the TNM stage and other variables. Conclusions: Two nomograms developed in this study precisely predicted the 3-, 5-, and 10-year OS and DSS rates of patients with SACC in accordance with independent prognostic factors, and their clinical value is better than TNM staging, providing a prognostic reference for other SACC patients.

Upregulation of IGF2BP2 Promotes Oral Squamous Cell Carcinoma Progression That Is Related to Cell Proliferation, Metastasis and Tumor-Infiltrating Immune Cells.

The strong invasive and metastatic abilities of oral squamous cell carcinoma (OSCC) cells in the early stage are the main reason for its poor prognosis. The early diagnosis and treatment of OSCC may reduce the metastasis rate and improve the survival rate. The aim of this study was to explore candidate biomarkers related to the prognosis and progression of OSCC. We performed weighted gene coexpression network analysis to identify key modules and genes associated with OSCC and intersected the differentially expressed genes (DEGs) in The Cancer Genome Atlas (TCGA)-OSCC and GSE30784 datasets. Next, we performed survival analysis and immunohistochemistry to screen and validate the hub gene insulin-like growth factor 2 (IGF2) mRNA binding protein 2 IGF2BP2. We also used TCGA pan-cancer data to verify that IGF2BP2 was expressed at high levels in a variety of cancers and was related to a poor prognosis in patients. Furthermore, we divided patients with OSCC into high and low expression groups based on the median expression level of IGF2BP2. Gene set enrichment analysis (GSEA) showed that IGF2BP2 led to a poor prognosis in OSCC by affecting cancer-related (epithelial-mesenchymal transition, glycolysis, cell cycle, etc.) and immune-related biological functions and pathways. Single-sample GSEA (ssGSEA), CIBERSORT, and xCell algorithms helped reveal that high IGF2BP2 expression was accompanied by a significant reduction in the immune score, stromal score, and microenvironment score and a decrease in the number of infiltrating CD8+ T cells in OSCC. In addition, silencing IGF2BP2 suppressed the proliferation, migration, and invasion of OSCC cells. In general, IGF2BP2 is a potential biomarker for the progression, immunotherapy response, and prognosis of OSCC.

The systemic inflammation response index predicts the survival of patients with clinical T1-2N0 oral squamous cell carcinoma.

OBJECTIVE: The systemic inflammation response index (SIRI) is an independent prognostic factor for many malignant tumors. However, the value of this factor in patients with clinical T1-2N0 (cT1-2N0) oral squamous cell carcinoma (OSCC) is still unclear. METHODS: We calculated SIRI of 235 cT1-2N0 OSCC patients from 2013 to 2017. Multivariate cox regression analysis was applied to verify the prognostic significance of SIRI. Kaplan-Meier curves were plotted to analyze the overall survival (OS) and disease-specific survival (DSS) for cT1-2N0 OSCC patients. RESULTS: According to the optimal cutoff point of SIRI, we divided cT1-2N0 OSCC patients into high SIRI group (SIRI ≥ 1.3) and low SIRI group (SIRI < 1.3). SIRI was an independent prognostic indicator for OS (HR = 2.87; 95% CI = 1.35-6.10; p = .006) and DSS (HR = 2.17; 95% CI = 1.10-4.27; p = .025). High SIRI had a significantly poorer OS (p = .001) and DSS (p = .007) in survival analysis than the low SIRI. Moreover, the prognostic value of SIRI was significantly stronger than neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-lymphocyte ratio (MLR). CONCLUSIONS: Preoperative SIRI can be regarded as a meaningful indicator for poor survival of cT1-2N0 OSCC patients, and it is a promising tool to formulate the best individualized treatment for high-risk patients.

N6-Methyladenosine Methyltransferase METTL14-Mediated Autophagy in Malignant Development of Oral Squamous Cell Carcinoma.

N6-methyladenosine (m6A) is the most abundant internal mRNA modification in eukaryotes and is related to stability, localization, or translation efficiency in tumorigenesis. Autophagy plays an important role in the occurrence and development of tumours. However, the relationship between m6A and autophagy remains unclear. In this study, we used a rapamycin-induced autophagy model of oral squamous cell carcinoma (OSCC) cells, and observed increased m6A RNA methylation. When autophagy was activated, the methyltransferase-like 14 (METTL14) expression was upregulated and influenced the proliferation, migration, and invasiveness of OSCC cells. Through meRIP-seq and RNA-seq analysis, we found that METTL14 directly combined with eukaryotic translation initiation factor gamma 1 (eIF4G1) mRNA and decreased its RNA stability. According to the dual-luciferase reporter and mutagenesis assay, the mutated site 1 of exon 11 of eIF4G1 is the key target of METTL14. Knockdown of the main m6A binding protein YTHDF2 may rescue the shortened half-life of eIF4G1 mRNA induced by METTL14 overexpression. Furthermore, an in vivo tumour xenograft model confirmed that a high METTL14 expression can effectively reduce OSCC growth. Additionally, using clinical samples, we found that patients with advanced or moderately/poorly differentiated tumours exhibited lower METTL14 levels. Taken together, our results revealed that METTL14 mediated eIF4G1 expression via m6A modification and regulated autophagy levels and biological functions in OSCC. Our findings not only expand our understanding of the correlation between autophagy and RNA methylation in tumorigenesis but also present an opportunity to develop new therapeutic options.

A Super-Enhancer Driven by FOSL1 Controls miR-21-5p Expression in Head and Neck Squamous Cell Carcinoma.

MiR-21-5p is one of the most common oncogenic miRNAs that is upregulated in many solid cancers by inhibiting its target genes at the posttranscriptional level. However, the upstream regulatory mechanisms of miR-21-5p are still not well documented in cancers. Here, we identify a super-enhancer associated with the MIR21 gene (MIR21-SE) by analyzing the MIR21 genomic regulatory landscape in head and neck squamous cell carcinoma (HNSCC). We show that the MIR21-SE regulates miR-21-5p expression in different HNSCC cell lines and disruption of MIR21-SE inhibits miR-21-5p expression. We also identified that a key transcription factor, FOSL1 directly controls miR-21-5p expression by interacting with the MIR21-SE in HNSCC. Moreover, functional studies indicate that restoration of miR-21-5p partially abrogates FOSL1 depletion-mediated inhibition of cell proliferation and invasion. Clinical studies confirmed that miR-21-5p expression is positively correlated with FOSL1 expression. These findings suggest that FOSL1-SE drives miR-21-5p expression to promote malignant progression of HNSCC.

N6-methyladenosine demethyltransferase FTO-mediated autophagy in malignant development of oral squamous cell carcinoma.

N6-methyladenosine (m6A) is the most abundant internal mRNA modification in eukaryotes and plays an important role in tumorigenesis. However, the underlying mechanism remains largely unclear. Here, we established a cell model of rapamycin-induced autophagy to screen m6A-modifying enzymes. We found that m6A demethylase fat mass and obesity-associated protein (FTO) plays a key role in regulating autophagy and tumorigenesis by targeting the gene encoding eukaryotic translation initiation factor gamma 1 (eIF4G1) in oral squamous cell carcinoma (OSCC). Knocked down of FTO expression in OSCC cell lines, resulting in downregulation of eIF4G1 along with enhanced autophagic flux and inhibition of tumorigenesis. Rapamycin inhibited FTO activity, and directly targeted eIF4G1 transcripts and mediated their expression in an m6A-dependent manner. Dual-luciferase reporter and mutagenesis assays confirmed that YTH N6-methyladenosine RNA-binding protein 2 (YTHDF2) targets eIF4G1. Conclusively, after FTO silencing, YTHDF2 captured eIF4G1 transcripts containing m6A, resulting in mRNA degradation and decreased expression of eIF4G1 protein, thereby promoting autophagy and reducing tumor occurrence. Therefore, rapamycin may regulate m6A levels, determining the autophagic flux of OSCC, thereby affecting the biological characteristics of cancer cells. This insight expands our understanding of the crosstalk between autophagy and RNA methylation in tumorigenesis, which is essential for therapeutic strategy development for OSCC.

FOSL1 promotes metastasis of head and neck squamous cell carcinoma through super-enhancer-driven transcription program.

Previously, we discovered that FOSL1 facilitates the metastasis of head and neck squamous cell carcinoma (HNSCC) cancer stem cells in a spontaneous mouse model. However, the molecular mechanisms remained unclear. Here, we demonstrated that FOSL1 serves as the dominant activating protein 1 (AP1) family member and is significantly upregulated in HNSCC tumor tissues and correlated with metastasis of HNSCC. Mechanistically, FOSL1 exerts its function in promoting tumorigenicity and metastasis predominantly via selective association with Mediators to establish super-enhancers (SEs) at a cohort of cancer stemness and pro-metastatic genes, such as SNAI2 and FOSL1 itself. Depletion of FOSL1 led to disruption of SEs and expression inhibition of these key oncogenes, which resulted in the suppression of tumor initiation and metastasis. We also revealed that the abundance of FOSL1 is positively associated with the abundance of SNAI2 in HNSCC and the high expression levels of FOSL1 and SNAI2 are associated with short overall disease-free survival. Finally, the administration of the FOSL1 inhibitor SR11302 significantly suppressed tumor growth and lymph node metastasis of HNSCC in a patient-derived xenograft model. These findings indicate that FOSL1 is a master regulator that promotes the metastasis of HNSCC through a SE-driven transcription program that may represent an attractive target for therapeutic interventions.

Silencing SHMT2 inhibits the progression of tongue squamous cell carcinoma through cell cycle regulation.

BACKGROUND: Serine hydroxymethyltransferase 2 (SHMT2) is a vital metabolic enzyme in one carbon metabolism catalyzing the conversion of serine to glycine, which has been reported to play a crucial role in the progression of tumors. However, its function in tongue squamous cell carcinoma (TSCC) remains unclear. METHODS: SHMT2 expression was analyzed using samples in online databases, and was assessed through immunohistochemistry staining of collected clinical specimens. The correlation between SHMT2 expression and the cell cycle was predicted through bioinformatic analysis, including weighted gene co-expression network analysis (WGCNA) and gene set enrichment analysis (GSEA). After transfection with siRNA, CCK8 assay, Edu staining, flow cytometry, trans-well assay, and wound healing experiments were performed to verify the functional role of SHMT2 in vitro. A stable cell line with SHMT2 silencing was established to detect the oncogenic function of SHMT2 in vivo. RESULTS: The expression of SHMT2 was up-regulated in TSCC tissues and cell lines compared with normal groups, and highly expressed SHMT2 significantly indicated a poorer clinical outcome for TSCC patients. Bioinformatic analysis found that high expression of SHMT2 was closely related with biologic process including cell cycle and cell cycle G1/S transition. Down regulating of SHMT2 significantly suppressed the proliferation, invasive and migrative ability of TSCC cells, and induced the prolongation of the G1 phase of the cell cycle in vitro. Furthermore, western blot showed that cell cycle-related regulators such as cyclin-dependent kinase 4 (CDK4) and cyclinD1 expression levels were decreased, while the expression levels of the cyclin-dependent kinase inhibitors p21Cip1 and p27Kip1 were increased after SHMT2 knockdown. Silencing SHMT2 in the HN6 cell line using short hairpin RNA also impeded tumor growth in vivo. CONCLUSIONS: Overexpression of SHMT2 in TSCC indicated low survival rates, and was associated with aggressive behaviors of TSCC. It was also found to be involved in cell cycle regulation of TSCC cells. SHMT2 may serve as a novel prognostic indicator of TSCC.

Impact of lymphovascular invasion in oral squamous cell carcinoma: A meta-analysis.

OBJECTIVE: Lymphovascular invasion (LVI) has been reported as a predictor of prognosis in multiple cancers. The aim of this meta-analysis was to investigate the potential value of LVI as a prognostic predictor of oral squamous cell carcinoma (OSCC). STUDY DESIGN: To identify relevant studies, PubMed, Embase, Web of Science, and Cochrane Library database were searched from inception to October 2020. All studies exploring the association of LVI with overall survival (OS), disease-specific survival (DSS), or disease-free survival (DFS) and lymph node metastasis (LNM) were identified. RESULT: Pooled odds ratios for LNM and hazard ratios for survival were calculated using fixed effects or random effects models. Thirty-six studies involving 17,109 patients with OSCC were included and further analyzed. The results showed that positive LVI was significantly associated with LNM and worse survival in patients with OSCC. Moreover, positive LVI was correlated with LNM in patients with early stage OSCC. CONCLUSIONS: These findings indicate that LVI may serve as a prognostic predictor for the metastasis and prognosis of OSCC and could be considered a routine pathologic examination in clinical work.

Development and Validation of Autophagy-Related Gene Signature and Nomogram for Predicting Survival in Oral Squamous Cell Carcinoma.

BACKGROUND: Autophagy, a highly conserved self-digesting process, has been deeply involved in the development and progression of oral squamous cell carcinoma (OSCC). However, the prognostic value of autophagy-related genes (ARGs) for OSCC still remains unclear. Our study set out to develop a multigene expression signature based on ARGs for individualized prognosis assessment in OSCC patients. METHODS: Based on The Cancer Genome Atlas (TCGA) database, we identified prognosis-related ARGs through univariate COX regression analysis. Then we performed the least absolute shrinkage and selection operator (LASSO) regression analysis to identify an optimal autophagy-related multigene signature with the subsequent validation in testing set, GSE41613 and GSE42743 datasets. RESULTS: We identified 36 prognosis-related ARGs for OSCC. Subsequently, the multigene signature based on 13 prognostic ARGs was constructed and successfully divided OSCC patients into low and high-risk groups with significantly different overall survival in TCGA training set (p < 0.0001). The autophagy signature remained as an independent prognostic factor for OSCC in univariate and multivariate Cox regression analyses. The area under the curve (AUC) values of the receiver operating characteristic (ROC) curves for 1, 3, and 5-year survival were 0.758, 0.810, 0.798, respectively. Then the gene signature was validated in TCGA testing set, GSE41613 and GSE42743 datasets. Moreover, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and single-sample gene set enrichment analysis (ssGSEA) revealed the underlying biological characteristics and signaling pathways associated with this signature in OSCC. Finally, we constructed a nomogram by combining the gene signature with multiple clinical parameters (age, gender, TNM-stage, tobacco, and alcohol history). The concordance index (C-index) and calibration plots demonstrated favorable predictive performance of our nomogram. CONCLUSION: In summary, we identified and verified a 13-ARGs prognostic signature and nomogram, which provide individualized prognosis evaluation and show insight for potential therapeutic targets for OSCC.

Activation of PGK1 under hypoxic conditions promotes glycolysis and increases stem cell­like properties and the epithelial­mesenchymal transition in oral squamous cell carcinoma cells via the AKT signalling pathway.

Although it has been previously documented that a hypoxic environment can promote glycolysis and the malignant progression of oral squamous cell carcinoma (OSCC) cells, the specific underlying mechanism remains unclear. Phosphoglycerate kinase 1 (PGK1) has been previously reported to serve an important role in tumor metabolism. The aim of the present study was to investigate the effects of hypoxia and PGK1 on glycolysis, stem cell­like properties and epithelial­mesenchymal transition (EMT) in OSCC cells. Cell Counting Kit­8 assays were performed to examine tumor cell viability under hypoxic conditions. Sphere formation, immunohistochemistry, western blotting, Transwell assays and mouse xenograft studies were performed to assess the biological effects of PGK1. Under hypoxic conditions, phosphoglycerate PGK1 expression was found to be upregulated, which resulted in the potentiation of stem cell­like properties and enhancement of EMT. However, PGK1 knockdown reversed hypoxia­mediated glycolysis, stem cell­like properties, EMT in addition to inhibiting OSCC cell invasion and migration. PGK1 knockdown also inhibited tumour growth, whilst the overexpression of PGK1 was demonstrated to promote tumour growth in mouse xenograft models in vivo. Downstream, activation of the AKT signalling pathway reversed the series of changes induced by PGK1 knockdown. PGK1 expression was found to be upregulated in human OSCC tissues, which was associated with the pathological differentiation of tumours and lymph node metastasis. To conclude, results from the present study demonstrate that hypoxia can increase PGK1 expression, resulting in the promotion of glycolysis, enhancing stem cell­like properties and EMT by activating AKT signalling in OSCC.

Neck nodal recurrence and survival of clinical T1-2 N0 oral squamous cell carcinoma in comparison of elective neck dissection versus observation: A meta-analysis.

OBJECTIVE: The clinical management of patients with T1-2 oral squamous cell carcinoma (OSCC) and clinically node-negative neck (cN0) continues to be controversial. We performed a systematic review of the literature to assess the effect of elective neck dissection (END) and neck observation (OBS) on the prognosis of patients with cT1-2 N0 OSCC. STUDY DESIGN: PubMed, Embase, and Cochrane Library were searched for studies related to END and OBS in patients with cT1-2 N0 OSCC. The Mantel-Haenszel method was used to pool odds ratios (OR) for neck nodal recurrence and hazard ratios (HR) for survival. RESULTS: END reduced the risk of neck nodal recurrence (OR 0.45; 95% confidence interval 0.32-0.63; P < .00001) in cT1-2 N0 OSCC. The disease-free survival (HR 0.52; 95% CI 0.42-0.63; P < .00001) was significantly higher in patients treated with END. However, END failed to significantly improve overall survival (HR 0.83; 95% CI 0.67-1.04; P = .10) and disease-specific survival (HR 0.87; 95% CI 0.48-1.57; P = .65) compared with management by OBS. CONCLUSIONS: A reduction in neck nodal recurrence and an increase in disease-free survival might support the need for END in early-stage OSCC with clinically N0 neck.

N6-methyladenosine demethylase FTO promotes M1 and M2 macrophage activation.

Macrophage polarization is the driving force of various inflammatory diseases, especially those involved in M1/M2 imbalance. N6-methyladenosine (m6A) is the most prevalent internal mRNA modification in eukaryotes that affects multiple biological processes, including those involved developmental arrest and immune response. However, the role of m6A in macrophage polarization remains unclear. This study found that FTO silencing significantly suppressed both M1 and M2 polarization. FTO depletion decreased the phosphorylation levels of IKKα/ß, IκBα and p65 in the NF-κB signaling pathway. The expression of STAT1 was downregulated in M1-polarized macrophages while the expression of STAT6 and PPAR-γ decreased in M2 polarization after FTO knockdown. The actinomycin D experiments showed that FTO knockdown accelerated mRNA decay of STAT1 and PPAR-γ. Furthermore, the stability and expression of STAT1 and PPAR-γ mRNAs increased when the m6A reader YTHDF2 was silenced. In conclusion, our results suggest that FTO knockdown inhibits the NF-κB signaling pathway and reduces the mRNA stability of STAT1 and PPAR-γ via YTHDF2 involvement, thereby impeding macrophage activation. These findings indicated a previously unrecognized link between FTO and macrophage polarization and might open new avenues for research into the molecular mechanisms of macrophage polarization-related diseases.

LDHA Promotes Oral Squamous Cell Carcinoma Progression Through Facilitating Glycolysis and Epithelial-Mesenchymal Transition.

Aerobic glycolysis is the main pathway for energy metabolism in cancer cells. It provides energy and biosynthetic substances for tumor progression and metastasis by increasing lactate production. Lactate dehydrogenase A (LDHA) promotes glycolysis process by catalyzing the conversion of pyruvate to lactate. Despite LDHA exhibiting carcinogenesis in various cancers, its role in oral squamous cell carcinoma (OSCC) remains unclear. This study demonstrated that LDHA was over-expressed in both OSCC tissues and cell lines, and was significantly associated with lower overall survival rates in patients with OSCC. Using weighted gene correlation network analysis and gene set enrichment analysis for the gene expression data of patients with OSCC (obtained from The Cancer Genome Atlas database), a close association was identified between epithelial-mesenchymal transition (EMT) and LDHA in promoting OSCC progression. The knockdown of LDHA suppressed EMT, cell proliferation, and migration and invasion of OSCC cells in vitro. Moreover, the silencing of LDHA inhibited tumor growth in vivo. Oxamate, as a competitive LDHA inhibitor, was also suppressed diverse malignant biocharacteristics of OSCC cells. Our findings reveal that LDHA acts as an oncogene to promote malignant progression of OSCC by facilitating glycolysis and EMT, and LDHA may be a potential anticancer therapeutic target.