Metabolic landscape of oral squamous cell carcinoma

METTL3-Mediated Maturation of miR-99a-5p Promotes Cell Migration and Invasion in Oral Squamous Cell Carcinoma by Targeting ZBTB7A

METTL3 is an important methyltransferase in N(6)-methyladenosine (m6A) modification. Recently, METTL3 mediates methylation of pri-microRNA (miRNA) to accelerate miRNA maturation, regulating tumor development. This study explored whether METTL3 mediated miR-99a-5p to influence oral squamous cell carcinoma (OSCC) cell metastasis. MiR-99a-5p, ZBTB7A, and MATTL3 expression was measured using quantitative real-time PCR. Biological behaviors were assessed using cell counting kit-8, flow cytometry, Transwell assay, as well as western blot. Luciferase reporter assay evaluated the interaction between miR-99a-5p and ZBTB7A. METTL3-regulated pri-miR-99a-5p processing was determined by RNA binding protein immunoprecipitation (RIP) and methylated RNA immunoprecipitation (MeRIP) assays. The consequences clarified that miR-99a-5p was upregulated in OSCC cells. Downregulation of miR-99a-5p suppressed cellular viability, migration, invasion, and epithelial-mesenchymal transition (EMT), and induced apoptosis. ZBTB7A acted as a miR-99a-5p target and reversed the effects on cellular behaviors induced by miR-99a-5p inhibitor. m6A content and METTL3 expression were increased in OSCC cells. METTL3 promoted the m6A modification of pri-miR-99a-5p and thereby facilitated miR-99a-5p processing. Moreover, knockdown of METTL3 inhibited OSCC metastasis by downregulating miR-99a-5p. Taken together, METTL3 promoted miR-99a-5p maturation in an m6A-dependent manner, which further targets ZBTB7A to accelerate the progression of OSCC. These findings suggest potential targets for OSCC therapy.

Circ_0004771 regulates malignant biological behaviors and has clinical significance in oral squamous cell carcinoma

BACKGROUND

The incidence of oral squamous cell carcinoma (OSCC) is increasing, and more effective treatment protocols must rapidly be developed to prevent the death of patients and ensure favorable outcomes. CircRNAs are a unique class of noncoding ribonucleic acid (RNA) molecules unaffected by RNA exonucleases. CircRNAs have more stable expression than linear RNAs and are not readily degraded; therefore, they are the newest focus of RNA research. Here, we analyze the mechanism of hsa_circ_0004771 (circ_0004771) in OSCC to provide a clinical reference.

METHODS

Circ_0004771 expression was measured in peripheral blood, cancerous tissues and adjacent tissues of OSCC patients. Patients were followed up for 3 years. The diagnostic value of circ_0004771 for OSCC occurrence, prognosis, recurrence and survival was analyzed with receiver operating characteristic (ROC) curves. OSCC cells were lentivirally transduced with a circ_0004771-silencing or an empty vector to evaluate alterations in cell growth, invasion, and apoptosis. Apoptosis-related and epithelial-mesenchymal transition (EMT)-related protein expression was quantified. BALB/c nude mice were used for tumorigenesis experiments to evaluate tumor growth in vivo after silencing circ_0004771.

RESULTS

Circ_0004771 expression was higher in peripheral blood and cancerous tissue of OSCC patients than in control peripheral blood and paracancerous tissue, respectively, exhibiting excellent predictive value for OSCC occurrence, prognosis, recurrence and survival. Silencing circ_0004771 decreased the growth, invasiveness, and EMT capacity and increased the apoptosis of OCC cells. In mice implanted with OSCC cells transduced with the circ_0004771-silencing lentiviral vector, the tumor growth capacity was obviously decreased.

CONCLUSION

Silencing circ_0004771 inhibits the malignant growth of OSCC.

Expression of FAP in Oral Leukoplakia and Oral Squamous Cell Carcinoma

OBJECTIVE

This study aimed to investigate the potential of fibroblast activation protein (FAP) as a biomarker in the progression of oral leukoplakia (OLK) carcinogenesis. This was achieved by evaluating FAP expression at different levels of the organisation, namely oral normal mucosa (NM), OLK, and oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

Altogether, 88 paraffin-embedded tissue samples were examined, including 55 cases of OLK, 13 cases of OSCC, and 20 cases of NM (control group). An exhaustive investigation was performed to examine FAP expression in NM, OLK, and OSCC tissues via immunohistochemistry (IHC). The relationship between FAP expression and clinical pathologic characteristics was analysed. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot (WB) also proved the expression of FAP in NM, OLK, and OSCC cells. Aberrant FAP expression in OLK and OSCC was explored using in vitro experiments.

RESULTS

Immunohistochemical results showed that high FAP expression was significantly correlated with histopathologic grade (P = .038) but not correlated with age, sex, or region (P = .953, .622, and .108, respectively). The expression level of FAP in NM tissues (0.15 ± 0.01) was minimal, whereas it was observed in OLK (0.28 ± 0.04) and OSCC (0.39 ± 0.02) tissues with a noticeable increase in expression levels (P < .001). The expression level of FAP in OLK with severe abnormal hyperplasia (S-OLK) tissues (0.33 ± 0.04) was significantly higher than in OLK with mild abnormal hyperplasia (MI-OLK, 0.26 ± 0.02) and OLK with moderate abnormal hyperplasia (MO-OLK, 0.28 ± 0.03) tissues (P < .001 and P = .039, respectively). The results of RT-PCR illustrated that the relative expression of FAP mRNA in OLK cells (2.63 ± 0.62) was higher than in NM cells (0.87 ± 0.14), but lower than in OSCC cells (5.63 ± 1.06; P = .027 and .012, respectively). FAP expression was minimal in NM cells (0.78 ± 0.06), modest in OLK cells (1.04 ± 0.06), and significantly elevated in OSCC cells (1.61 ± 0.09) based on the results of WB (P < .001).

CONCLUSIONS

Significant variations in FAP expression were observed in NM, OLK, and OSCC tissues and cells. These findings revealed that FAP may be a reliable biomarker for the early diagnosis and evaluation of OLK carcinogenesis.

Oral tongue squamous cell carcinoma diagnosis from tissue metabolic profiling

OBJECTIVE

Disease metabolomes have been studied for identifying diagnostic and predictive biomarkers of pathology. Oral tongue squamous cell carcinoma (OTSCC) is one of the most prevalent subtypes of head and neck squamous cell carcinoma, yet the profile and diagnostic value of its tissue metabolite are unclear.

SUBJECTS AND METHODS

Tumor tissue samples and matched normal mucosal tissue samples were collected from 40 OTSCC patients. Untargeted metabolic analysis by liquid chromatography-mass spectrometry/mass spectrometry, in positive and negative ion modes, was used to identify dysregulated metabolites in OTSCC. Further, utilizing LASSO regression and receiver operating characteristic analyses, biomarker metabolites were selected and validated, and a diagnostic model was established.

RESULTS

One hundred and ninety metabolites were detected. The OTSCC had a total of 89 dysregulated metabolites, of which 73 were elevated. A diagnostic panel of nine metabolites was subsequently created that could accurately identify OTSCC with 100% sensitivity of 100%, 100% specificity and an AUC of 1.00.

CONCLUSIONS

This study identified distinct metabolic characteristics of OTSCC and established a diagnostic model. Our research also contributes to the investigation of the pathogenesis of OTSCC.

MALAT1 as a potential salivary biomarker in oral squamous cell carcinoma through targeting miRNA-124

OBJECTIVES

To determine the diagnostic accuracy of the long non-coding RNA "MALAT1" measured in the saliva of patients with oral squamous cell carcinoma (OSCC) and assess the salivary expression of microRNA-124, which MALAT1 targets.

SUBJECTS AND METHODS

Forty subjects were collected in a consecutive pattern and allocated into two groups. Group A included 20 patients with OSCC, while Group B included 20 healthy subjects. Salivary expression of MALAT1 and microRNA (miRNA)-124 was evaluated in the two study groups using quantitative real-time polymerase chain reaction and correlated with histopathological examination of OSCC subjects.

RESULTS

OSCC yielded a statistically significant higher expression of MALAT1 than healthy controls and a lower expression of miRNA-124 in OSCC than controls. There is a statistically significant inverse relationship between salivary MALAT1 and miRNA-124. Moreover, there is a statistically significant difference in the MALAT1 expression in saliva samples from metastatic cases compared with non-metastatic cases, as well as in patients with lymph node involvement compared with those without involvement. At a cut-off value of 2.24, salivary MALAT1 exhibited 95% sensitivity and 90% specificity in differentiating OSCC from healthy subjects.

CONCLUSION

Salivary MALAT1 acts as a sponge for miRNA-124 and could be a potential salivary biomarker for OSCC.

CDK1 and CCNA2 play important roles in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a malignant tumor that occurs in oral cavity and is dominated by squamous cells. The relationship between CDK1, CCNA2, and OSCC is still unclear. The OSCC datasets GSE74530 and GSE85195 configuration files were downloaded from the Gene Expression Omnibus (GEO) database and were derived from platforms GPL570 and GPL6480. Differentially expressed genes (DEGs) were screened. The weighted gene co-expression network analysis, functional enrichment analysis, gene set enrichment analysis, construction and analysis of protein-protein interaction (PPI) network, Comparative Toxicogenomics Database analysis were performed. Gene expression heatmap was drawn. TargetScan was used to screen miRNAs that regulate central DEGs. A total of 1756 DEGs were identified. According to Gene Ontology (GO) analysis, they were predominantly enriched in processes related to organic acid catabolic metabolism, centromeric, and chromosomal region condensation, and oxidoreductase activity. In Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, the DEGs were mainly concentrated in metabolic pathways, P53 signaling pathway, and PPAR signaling pathway. Weighted gene co-expression network analysis was performed with a soft-thresholding power set at 9, leading to the identification of 6 core genes (BUB1B, CCNB1, KIF20A, CCNA2, CDCA8, CDK1). The gene expression heatmap revealed that core genes (CDK1, CCNA2) were highly expressed in OSCC samples. Comparative Toxicogenomics Database analysis demonstrated associations between the 6 genes (BUB1B, CCNB1, KIF20A, CCNA2, CDCA8, CDK1) and oral tumors, precancerous lesions, inflammation, immune system disorders, and tongue tumors. The associated miRNAs for CDK1 gene were hsa-miR-203a-3p.2, while for CCNA2 gene, they were hsa-miR-6766-3p, hsa-miR-4782-3p, and hsa-miR-219a-5p. CDK1 and CCNA2 are highly expressed in OSCC. The higher the expression of CDK1 and CCNA2, the worse the prognosis.

The metabolic reprogramming of γ-aminobutyrate in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy. The oncometabolites have been studied in OSCC, but the mechanism of metabolic reprogramming remains unclear. To identify the potential metabolic markers to distinguish malignant oral squamous cell carcinoma (OSCC) tissue from adjacent healthy tissue and study the mechanism of metabolic reprogramming in OSCC. We compared the metabolites between cancerous and paracancerous tissues of OSCC patients by 1HNMR analysis. We established OSCC derived cell lines and analyzed their difference of RNA expression by RNA sequencing. We investigated the metabolism of γ-aminobutyrate in OSCC derived cells by real time PCR and western blotting. Our data revealed that much more γ-aminobutyrate was produced in cancerous tissues of OSCC patients. The investigation based on OSCC derived cells showed that the increase of γ-aminobutyrate was promoted by the synthesis of glutamate beyond the mitochondria. In OSCC cancerous tissue derived cells, the glutamate was catalyzed to glutamine by glutamine synthetase (GLUL), and then the generated glutamine was metabolized to glutamate by glutaminase (GLS). Finally, the glutamate produced by glutamate-glutamine-glutamate cycle was converted to γ-aminobutyrate by glutamate decarboxylase 2 (GAD2). Our study is not only benefit for understanding the pathological mechanisms of OSCC, but also has application prospects for the diagnosis of OSCC.

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

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

Biological biomarkers of oral cancer

The oral squamous cell carcinoma (OSCC) 5 year survival rate of 41% has marginally improved in the last few years, with less than a 1% improvement per year from 2005 to 2017, with higher survival rates when detected at early stages. Based on histopathological grading of oral dysplasia, it is estimated that severe dysplasia has a malignant transformation rate of 7%-50%. Despite these numbers, oral dysplasia grading does not reliably predict its clinical behavior. Thus, more accurate markers predicting oral dysplasia progression to cancer would enable better targeting of these lesions for closer follow-up, especially in the early stages of the disease. In this context, molecular biomarkers derived from genetics, proteins, and metabolites play key roles in clinical oncology. These molecular signatures can help predict the likelihood of OSCC development and/or progression and have the potential to detect the disease at an early stage and, support treatment decision-making and predict treatment responsiveness. Also, identifying reliable biomarkers for OSCC detection that can be obtained non-invasively would enhance management of OSCC. This review will discuss biomarkers for OSCC that have emerged from different biological areas, including genomics, transcriptomics, proteomics, metabolomics, immunomics, and microbiomics.

Circ_0058063 Contributed to Oral Squamous Cell Carcinoma Development by Sponging miR-145 and Regulating PI3K/AKT Pathway

BACKGROUND

Circular RNAs (circRNAs) are key regulators of oral squamous cell carcinoma (OSCC) progression. In this study, we aimed to clarify the regulatory roles of circ_0058063 and its effect on tumorigenesis in OSCC.

METHODS

Quantitative real-time polymerase chain reaction was conducted to determine the expression levels of microRNA (miR)-145-5p and circ_0058063 in OSCC. Cell viability, adhesion, migration, and epithelial-mesenchymal transition (EMT) of OSCC cells were assessed using cell counting kit-8, cell adhesion, and transwell assays. Western blotting was performed to determine the phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT) phosphorylation levels. Xenograft tumor models were constructed to evaluate the tumorigenicity of OSCC cells in vivo. In addition, the interaction between circ_0058063 and miR-145-5p was validated via luciferase reporter and RNA immunoprecipitation assays.

RESULTS

Expression levels of circ_0058063 were elevated, whereas those of miR-145-5p were decreased in OSCC. Upregulation of circ_0058063 levels enhanced the viability, adhesion, migration, and EMT of OSCC cells in vitro and promoted tumorigenicity in vivo. Moreover, circ_0058063 promoted OSCC growth by upregulating the PI3K and AKT phosphorylation levels. miR-145-5p overexpression considerably inhibited the PI3K/AKT pathway and decreased OSCC cell viability, adhesion, migration, and EMT. Mechanistically, circ_0058063 sponged miR-145-5p and activated the PI3K/AKT pathway in OSCC cells.

CONCLUSION

Our results revealed that circ_0058063 functions as an oncogene via regulation of the PI3K/AKT pathway by targeting miR-145-5p in OSCC, suggesting its potential for OSCC diagnosis and treatment.

ENAH-202 promotes cancer progression in oral squamous cell carcinoma by regulating ZNF502/VIM axis

BACKGROUND

We aimed to demonstrate the regulatory effect of long non-coding RNA (lncRNA) ENAH-202 on oral squamous cell carcinoma (OSCC) development as well as its molecular mechanism.

METHODS

We detected ENAH-202 expression in OSCC tissues and cell lines by quantitative real-time PCR (qPCR). The biological function of ENAH-202 was assessed in vitro and in vivo using CCK-8, colony formation assays, transwell assays, xenograft formation, and tail vein injection. The further molecular mechanism by which ENAH-202 promoted OSCC progression was identified using RNA pull-down, LS-MS/MS analysis, RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (ChIP) assays.

RESULTS

ENAH-202 was significantly upregulated in OSCC tissues and cells. ENAH-202 promoted OSCC cell proliferation, migration, and invasion in vitro and in vivo. The expression of enabled homolog (ENAH) and epithelial-to-mesenchymal transition (EMT)-related proteins was changed with the expression of ENAH-202. Moreover, ENAH-202 promoted the transcription of Vimentin (VIM) by binding with ZNF502, which can help ENAH-202 promote OSCC progression.

CONCLUSIONS

ENAH-202 facilitated OSCC cell proliferation and metastasis by regulating ZNF502/VIM axis, which played an important role in OSCC progression.

Enhancing head and neck tumor management with artificial intelligence: Integration and perspectives

Head and neck tumors (HNTs) constitute a multifaceted ensemble of pathologies that primarily involve regions such as the oral cavity, pharynx, and nasal cavity. The intricate anatomical structure of these regions poses considerable challenges to efficacious treatment strategies. Despite the availability of myriad treatment modalities, the overall therapeutic efficacy for HNTs continues to remain subdued. In recent years, the deployment of artificial intelligence (AI) in healthcare practices has garnered noteworthy attention. AI modalities, inclusive of machine learning (ML), neural networks (NNs), and deep learning (DL), when amalgamated into the holistic management of HNTs, promise to augment the precision, safety, and efficacy of treatment regimens. The integration of AI within HNT management is intricately intertwined with domains such as medical imaging, bioinformatics, and medical robotics. This article intends to scrutinize the cutting-edge advancements and prospective applications of AI in the realm of HNTs, elucidating AI's indispensable role in prevention, diagnosis, treatment, prognostication, research, and inter-sectoral integration. The overarching objective is to stimulate scholarly discourse and invigorate insights among medical practitioners and researchers to propel further exploration, thereby facilitating superior therapeutic alternatives for patients.

FSCN1 promotes proliferation, invasion and glycolysis via the IRF4/AKT signaling pathway in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a disease with increasing incidence worldwide that leads to deformity and death. In OSCC, fascin actin-bundling protein 1 (FSCN1) is an oncogene involved in the tumorigenesis process. However, the functions and potential mechanisms of FSCN1 in the OSCC tumorigenesis process have not been reported thus far.

METHODS

We used qRT‒PCR to detect the expression of FSCN1 in 40 paired OSCC tumor tissues (tumor) and neighboring noncancerous tissues. The role of FSCN1 was also assessed in vitro through colony formation, CCK-8, and transwell assays. Moreover, glucose consumption was detected. Western blotting was used to confirm the interaction of FSCN1, IRF4 and AKT.

RESULTS

FSCN1 was remarkably overexpressed in OSCC tissues and cell lines compared to corresponding controls. In addition, colony formation, CCK-8, and transwell assays revealed a notable reduction in OSCC growth and invasion when FSCN1 was silenced. FSCN1 silencing remarkably suppressed OSCC glycolysis. Mechanistic studies showed that FSCN1 achieves its function partially by activating interferon regulatory factor 4 (IRF4) and the AKT pathway in OSCC.

CONCLUSION

In conclusion, our study investigated the functions and mechanisms of the FSCN1/IRF4/AKT pathway in OSCC progression. In OSCC, FSCN1 is likely to be a biomarker and therapeutic target.

Plasma metabolomics of oral squamous cell carcinomas based on NMR and MS approaches provides biomarker identification and survival prediction

Metabolomics has proven to be an important omics approach to understand the molecular pathways underlying the tumour phenotype and to identify new clinically useful markers. The literature on cancer has illustrated the potential of this approach as a diagnostic and prognostic tool. The present study aimed to analyse the plasma metabolic profile of patients with oral squamous cell carcinoma (OSCC) and controls and to compare patients with metastatic and primary tumours at different stages and subsites using nuclear magnetic resonance and mass spectrometry. To our knowledge, this is the only report that compared patients at different stages and subsites and replicates collected in diverse institutions at different times using these methodologies. Our results showed a plasma metabolic OSCC profile suggestive of abnormal ketogenesis, lipogenesis and energy metabolism, which is already present in early phases but is more evident in advanced stages of the disease. Reduced levels of several metabolites were also associated with an unfavorable prognosis. The observed metabolomic alterations may contribute to inflammation, immune response inhibition and tumour growth, and may be explained by four nonexclusive views-differential synthesis, uptake, release, and degradation of metabolites. The interpretation that assimilates these views is the cross talk between neoplastic and normal cells in the tumour microenvironment or in more distant anatomical sites, connected by biofluids, signalling molecules and vesicles. Additional population samples to evaluate the details of these molecular processes may lead to the discovery of new biomarkers and novel strategies for OSCC prevention and treatment.

ANO1-downregulation induced by schisandrathera D: a novel therapeutic target for the treatment of prostate and oral cancers

Anoctamin 1 (ANO1), a drug target for various cancers, including prostate and oral cancers, is an intracellular calcium-activated chloride ion channel that plays various physiopathological roles, especially in the induction of cancer growth and metastasis. In this study, we tested a novel compound isolated from Schisandra sphenanthera, known as schisandrathera D, for its inhibitory effect on ANO1. Schisandrathera D dose-dependently suppressed the ANO1 activation-mediated decrease in fluorescence of yellow fluorescent protein; however, it did not affect the adenosine triphosphate-induced increase in the intracellular calcium concentration or forskolin-induced cystic fibrosis transmembrane conductance regulator activity. Specifically, schisandrathera D gradually decreased the levels of ANO1 protein and significantly reduced the cell viability in ANO1-expressing cells when compared to those in ANO1-knockout cells. These effects could be attributed to the fact that schisandrathera D displayed better binding capacity to ANO1 protein than the previously known ANO1 inhibitor, Ani9. Finally, schisandrathera D increased the levels of caspase-3 and cleaved poly (ADP-ribose) polymerase 1, thereby indicating that its anticancer effect is mediated through apoptosis. Thus, this study highlights that schisandrathera D, which reduces ANO1 protein levels, has apoptosis-mediated anticancer effects in prostate and oral cancers, and thus, can be further developed into an anticancer agent.

FBXW7 promotes autophagy and inhibits proliferation of oral squamous cell carcinoma

BACKGROUND

F-box and WD repeat domain containing 7 (FBXW7) is a critical tumor suppressor. The expression of FBXW7 is decreased in oral squamous cell carcinoma (OSCC) tissues and shows diagnosis value. We aimed to investigate the influence of FBXW7 overexpression on OSCC cell proliferation and autophagy.

METHODS

In Balb/c nude mice, CAL27 xenograft tumor model was established. Western blot was employed to evaluate protein level. Messenger RNA level was analyzed by quantitative reverse transcription-polymerase chain reaction. Colony formation assay and MTT assay were employed to evaluate cell proliferation.

RESULTS

FBXW7 expression was decreased in OSCC cell lines. FBXW7 inhibited cell proliferation of SCC9 and CAL27. FBXW7 increased Autophagy related 7 (Atg7), Beclin1 (BECN1), B-cell lymphoma 2 (BCL2) -associated X (BAX), BCL2 antagonist killer (BAK), and microtubule-associated protein 1 light chain 3 (LC3) levels and decreased MCL1 and BCL2 levels in CAL27 cells. FBXW7 decreased tumor volume and weight in CAL27 xenograft tumor model. FBXW7 increased BECN1, Atg7, and LC3 levels in CAL27 xenograft tumor model.

CONCLUSION

In conclusion, decreased expression of FBXW7 is confirmed in diverse OSCC cell lines. The enhanced FBXW7 expression inhibits cancer cell proliferation and promotes autophagy in both OSCC cells and xenograft tumor model.

lncRNA HOXA11-AS maintains the stemness of oral squamous cell carcinoma stem cells and reduces the radiosensitivity by targeting miR-518a-3p/PDK1

OBJECTIVE

Oral squamous cell carcinoma (OSCC) is the most prevailing oral malignancy. The lncRNA HOXA11-AS shows prominent roles in OSCC. This study explored the effects of lncRNA HOXA11-AS on regulating OSCC stem cell stemness and radiosensitivity by targeting miR-518a-3p/PDK1.

METHODS

Human OSCC cell lines SCC9 and SCC15 were selected. CD133⁺ cancer stem cells (CSCs) were sorted by immunomagnetic beads. CD133 expression in cells and HOXA11-AS expression in SCC9, SCC15, and CD133⁺ SCC9, CD133⁺ SCC15 cells were assessed by flow cytometry and RT-qPCR. HOXA11-AS was silenced/overexpressed in SCC9, SCC15, CD133⁺ SCC9, and CD133⁺ SCC15 cells. Cell proliferation, radiosensitivity, invasion, and stem cell sphere formation ability were examined by CCK-8, colony formation, Transwell, and stem cell sphere formation. The levels of stemness-related genes (Oct4, Nanog, Sox2), miR-518a-3p, epithelial-mesenchymal transition (EMT)-related proteins (E-cadherin, Vimentin, N-cadherin), and PDK1 were assessed by RT-qPCR and Western blot assay.

RESULTS

HOXA11-AS was up-regulated in SCC9, SCC15, CD133⁺ SCC9, and CD133⁺ SCC15 cells. HOXA11-AS silencing inhibited OSCC proliferation and invasion and enhanced radiosensitivity. HOXA11-AS maintained CSC stemness in OSCC. HOXA11-AS silencing reduced CD133⁺ SCC9 and CD133⁺ SCC15 stem cell sphere formation ability, reduced stem cell stemness-related gene levels, and inhibited EMT. HOXA11-AS regulated OSCC stem cell stemness and radiosensitivity by targeting miR-518a-3p. PDK1 overexpression annulled the regulatory effects of HOXA11-AS silencing on OSCC cell stem cell stemness and radiosensitivity.

CONCLUSION

In vitro lncRNA HOXA11-AS silencing inhibited OSCC stem cell stemness by targeting the miR-518a-3p/PDK1 axis, thus enhancing OSCC cell radiosensitivity.

RELA promotes the progression of oral squamous cell carcinoma via TFAP2A-Wnt/β-catenin signaling

Oral squamous cell carcinoma (OSCC) has emerged as the most prevailing oral malignancy worldwide, characterized by cervical solid lymph node metastasis and strong local invasiveness. Overexpression of Transcription Factor AP-2 alpha (TFAP2A) is observed in a significant proportion of OSCC cases. In this study, we aimed to elucidate the function of TFAP2A in the progression of OSCC and the related molecular signaling pathways. The role of RELA was predicted using bioinformatics analysis. The mRNA abundances of RELA, TFAP2A, and β-catenin were assessed by Western blot and quantitative real-timePCR. The relationship between RELA, TFAP2A, and β-catenin and their correlation with clinicopathological characteristics of OSCC was evaluated. The target of RELA and TFAP2A was identified by the chromatin immunoprecipitation as well as luciferase reporter assay. The colony formation assay and MTS assay were performed to determine the proliferative level of OSCC cells. OSCC cell motility was determined by Transwell assay and wound-healing assay. The protein expressions of epithelial-mesenchymal transition-associated factors were evaluated by Western blot. The expressions of RELA and TFAP2A were elevated in OSCC, and their expressions displayed a positive correlation. The expression levels of RELA and TFAP2A were found to be associated with TNM staging and lymphatic metastasis of OSCC patients. RELA upregulation promoted OSCC progression, as manifested by increased levels of proliferation, invasion, and migration of OSCC cells. We also demonstrated that RELA was directly bound to the promoter of TFAP2A transcription, which activated multiple malignant and metastatic phenotypes. Furthermore, TFAP2A activated the Wnt/β-catenin signaling by targeting the promoter regions of β-catenin. The study found that RELA is critical for promoting the progression of OSCC via the RELA-TFAP2A-Wnt/β-catenin signaling pathway. The RELA-TFAP2A-Wnt/β-catenin signaling pathway is a potential target for reducing the aggressiveness of OSCC.

Implications of altered sirtuins in metabolic regulation and oral cancer

Sirtuins (SIRTs 1-7) are a group of histone deacetylase enzymes with a wide range of enzyme activities that target a range of cellular proteins in the nucleus, cytoplasm, and mitochondria for posttranslational modifications by acetylation (SIRT1, 2, 3, and 5) or ADP ribosylation (SIRT4, 6, and 7). A variety of cellular functions, including mitochondrial functions and functions in energy homeostasis, metabolism, cancer, longevity and ageing, are regulated by sirtuins. Compromised sirtuin functions and/or alterations in the expression levels of sirtuins may lead to several pathological conditions and contribute significantly to alterations in metabolic phenotypes as well as oral carcinogenesis. Here, we describe the basic characteristics of seven mammalian sirtuins. This review also emphasizes the key molecular mechanisms of sirtuins in metabolic regulation and discusses the possible relationships of sirtuins with oral cancers. This review will provide novel insight into new therapeutic approaches targeting sirtuins that may potentially lead to effective strategies for combating oral malignancies.

Anticancer effects of licochalcones: A review of the mechanisms

Cancer is a disease with a high fatality rate representing a serious threat to human health. Researchers have tried to identify effective anticancer drugs. Licorice is a widely used traditional Chinese medicine with various pharmacological properties, and licorice-derived flavonoids include licochalcones like licochalcone A, licochalcone B, licochalcone C, licochalcone D, licochalcone E, and licochalcone H. By regulating the expression in multiple signaling pathways such as the EGFR/ERK, PI3K/Akt/mTOR, p38/JNK, JAK2/STAT3, MEK/ERK, Wnt/β-catenin, and MKK4/JNK pathways, and their downstream proteins, licochalcones can activate the mitochondrial apoptosis pathway and death receptor pathway, promote autophagy-related protein expression, inhibit the expression of cell cycle proteins and angiogenesis factors, regulate autophagy and apoptosis, and inhibit the proliferation, migration, and invasion of cancer cells. Among the licochalcones, the largest number of studies examined licochalcone A, far more than other licochalcones. Licochalcone A not only has prominent anticancer effects but also can be used to inhibit the efflux of antineoplastic drugs from cancer cells. Moreover, derivatives of licochalcone A exhibit strong antitumor effects. Currently, most results of the anticancer effects of licochalcones are derived from cell experiments. Thus, more clinical studies are needed to confirm the antineoplastic effects of licochalcones.

Mediation of PKM2-dependent glycolytic and non-glycolytic pathways by ENO2 in head and neck cancer development

BACKGROUND

Enolase 2 (ENO2) is a crucial glycolytic enzyme in cancer metabolic process and acts as a "moonlighting" protein to play various functions in diverse cellular processes unrelated to glycolysis. ENO2 is highly expressed in head and neck squamous cell carcinoma (HNSCC) tissues relative to normal tissues; however, its impact and underlying regulatory mechanisms in HNSCC malignancy remain unclear.

METHODS

Molecular alterations were examined by bioinformatics, qRT-PCR, western blotting, immunofluorescence, immunohistochemistry, immunoprecipitation, and ChIP-PCR assays. Metabolic changes were assessed by intracellular levels of ATP and glucose. Animal study was used to evaluate the therapeutic efficacy of the ENO inhibitor.

RESULTS

ENO2 is required for HNSCC cell proliferation and glycolysis, which, surprisingly, is partially achieved by controlling PKM2 protein stability and its nuclear translocation. Mechanistically, loss of ENO2 expression promotes PKM2 protein degradation via the ubiquitin-proteasome pathway and prevents the switch of cytoplasmic PKM2 to the nucleus by inactivating AKT signaling, leading to a blockade in PKM2-mediated glycolytic flux and CCND1-associated cell cycle progression. In addition, treatment with the ENO inhibitor AP-III-a4 significantly induces HNSCC remission in a preclinical mouse model.

CONCLUSION

Our work elucidates the signaling basis underlying ENO2-dependent HNSCC development, providing evidence to establish a novel ENO2-targeted therapy for treating HNSCC.

The prognostic role and metabolic function of GGPS1 in oral squamous cell carcinoma

Background: GGPS1(geranylgeranyl diphosphate synthase 1) is a member of the prenyltransferase family. Abnormal expression of GGPS1 can disrupt the balance between protein farnesylation and geranylgeranylation, thereby affecting a variety of cellular physiologic and pathological processes. However, it is still unknown how this gene could contribute to the prognosis of oral squamous cell carcinoma (OSCC). This study aimed to explore the prognostic role of GGPS1 in OSCC and its relationship with clinical features. Methods: The RNA-seq data and clinical data were obtained from TCGA. The survival analyses, Cox regression analyses, ROC curves, nomograms, calibration curves, and gene function enrichments were established by R software. Results: The results showed that the high expression of GGPS1 in OSCC is related to poor prognosis. At the same time, multivariate Cox regression analyses showed that GGPS1 could be an independent prognostic biomarker, and its gene expression level is closely related to the histological stage of cancer. GGPS1 may promote tumorigenesis because of its metabolic function. Conclusion: This study came to a conclusion that GGPS1, whose high expression has a significantly unfavorable meaning toward the prognosis of OSCC, can act as a novel independent biomarker for OSCC.

Hsa_circ_0049396 inhibited oral squamous cell carcinoma progression by regulating the miR-663b/ENDOU axis

BACKGROUND

Circular RNA (circRNAs) play an important role in oral squamous cell carcinoma (OSCC) progression and has been widely reported. In this study, we aimed to investigate the role of a novel circRNA, circ_0049396, and its underlying mechanism in OSCC.

METHODS

The expression levels of circ_0049396, miR-663b, and theuridylate-specific endoribonuclease (ENDOU) were assessed by quantitative reverse transcription PCR (qRT-PCR). Cell proliferation and migration were evaluated using CCK-8 and Transwell assays, respectively. Western blotting was performed to measure the levels of the apoptosis-associated proteins (Bcl-2 and Bax). The functional role of circ _0049396 was further validated in a xenograft experiment in vivo. The interactions of miR-663b with circ_0049396/ENDOU were verified using the dual luciferase reporter, RNA pull-down, and RNA immunoprecipitation (RIP) assays.

RESULTS

The expression of circ_0049396 and ENDOU was downregulated in OSCC tissues and cells, whereas miR-663b was upregulated. Circ_0049396 overexpression weakened OSCC cell proliferation and migration but enhanced their apoptosis. Circ_0049396 overexpression suppresses tumorigenesis in vivo. The circ_0049396/miR-663b/ENDOU regulatory network predicted through bioinformatic analysis was validated using RNA pull-down, luciferase reporter, and RIP experiments. MiR-663b mimic enhanced the migratory and proliferative abilities of OSCC cells, but suppressed apoptosis. Furthermore, circ_0049396 or ENDOU overexpression partially reversed the malignant behavior of miR-663b-overexpressing OSCC cells.

CONCLUSIONS

Our study illustrated that circ_0049396 overexpression inhibited the malignant behavior of OSCC cells by regulating the miR-663b/ENDOU axis. Based on our findings, circ_0049396 can be used as a potential therapeutic agent for OSCC.

Chronic restraint stress promotes the tumorigenic potential of oral squamous cell carcinoma cells by reprogramming fatty acid metabolism via CXCL3 mediated Wnt/β-catenin pathway

Chronic stress promotes tumor progression and may harm homeostasis of energy metabolism by disrupting key metabolic processes. Recently, emerging evidence that chemokines CXCL3 as a novel adipokine plays a new role in lipid metabolism and various human malignancies. However, the role and mechanism of the CXCL3 in oral squamous cell carcinoma (OSCC) progression and reprogramming lipid metabolism induced by chronic restraint stress is unclear. The analysis of transcriptome sequencing, LC-MS, GC-MS, CCK8, cell apoptosis assays, cell cycle analysis, qRT-PCR, ELISA, western blotting, immunofluorescence, immunohistochemistry, RNA interference and lentivirus transfection and a xenograft tumor growth and chronic restraint stress model were used to investigate the role of CXCL3 in the regulation of lipid metabolism and OSCC and explore the underlying molecular mechanisms. We showed that CXCL3 plays a critical role in in fatty acid de novo synthesis and tumor growth induced by chronic restraint stress. We demonstrated that chronic restraint stress promoted lipid accumulation, OSCC growth and metastasis in a mouse xenograft model. CXCL3 knockdown and FH535, an inhibitor of Wnt/β-catenin pathway, could attenuate fatty acid de novo synthesis, cell proliferation and epithelial-mesenchymal transition induced by chronic restraint stress in OSCC cells. Our findings demonstrate that chronic restraint stress promotes the proliferation and metastasis of OSCC by reprogramming fatty acid metabolism via CXCL3 mediated Wnt/β-catenin pathway. Our study provides novel insights to help understand the underlying mechanisms of CXCL3 in OSCC progression induced by chronic restraint stress.

Association of Kaiso and partner proteins in oral squamous cell carcinoma

Objectives

1. Identification of protein expression and subcellular localization of E-cadherin (E-cad), p120 catenin (P120ctn), and Kaiso in oral cancer (OC). 2. To study the protein expression of cyclin D1 and c-Myc (Kaiso targets) and determine their relationship with the expression and localization of Kaiso.

Methods

Histological grading was performed in accordance with Broder's criteria. Expression and localization data for E-cad, p120ctn, Kaiso, cyclin D1, and c-Myc were acquired using immunohistochemistry. Data were analyzed using SPSS version 21. The chi-square test was used to measure the statistical significance of associations, with p < 0.05 as statistically significant.

Results

Of 47 OC cases, 36% showed low E-cad expression and 34% showed low p120ctn. Low Kaiso expression was recognized in 78% of tumor specimens. Aberrant cytoplasmic localization of p120ctn was seen in 80.8% cases. Cytoplasmic Kaiso localization was appreciated in 87% of tumor tissues, whereas 29.7% lacked any nuclear Kaiso. Kaiso expression was significantly associated with the expression of cyclin D1 but not with c-Myc.

Conclusion

The present study identified a change in the localization of Kaiso in OC. The significance of this in relation to OC and tumor prognosis needs to be investigated with further studies using larger sample sizes and more sensitive molecular tools.

MKI67 an potential oncogene of oral squamous cell carcinoma via the high throughput technology

Oral squamous cell carcinoma is a malignant tumor that occurs in the oral cavity, with poor prognosis and easy recurrence. However, the relationship between MKI67 and oral squamous cell carcinoma remains unclear. The oral squamous cell carcinoma datasets GSE138206, GSE146483 and GSE184616 were downloaded from the gene expression omnibus database, and the differentially expressed genes (DEGs) were screened. The protein-protein interaction network was constructed and analyzed by search tool for the retrieval of interacting genes database and Cytoscape software. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) were used for functional enrichment analysis. GO and KEGG analyses were performed on the whole genome, as formulated by gene set enrichment analysis. comparative toxicogenomics database was used to identify the diseases most associated with the core genes. TargetScan was used to screen miRNA regulating central DEGs. A total of 1472 DEGs were identified. GO analysis showed that the differentially expressed genes were mainly enriched in the tissues of extracellular matrix, type i interferon signaling pathway, human papillomavirus infection, adhesion spot, hepatitis C and ECM-receptor interaction. Enrichment items were similar to GO and KEGG enrichment items of differentially expressed genes. 10 core genes were obtained, and their expression was different between oral squamous cell carcinoma and normal tissue samples. MKI67 is highly expressed in oral squamous cell carcinoma and may be an oncogene in oral squamous cell carcinoma.

COL11A1 as a potential prognostic target for oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a malignant tumor occurring in the oral cavity. However, the molecular mechanism of OSCC is not clear. Bioinformatics was used to screen and identify role of collagen type X1 alpha 1 (COL11A1) on OSCC. 200 patients with OSCC were recruited. Clinical and follow-up data were recorded and COL11A1 expression levels were tested. Pearson chi-square test and Spearman correlation coefficient were used to analyze relationship between prognosis and related parameters in patients with OSCC. Univariate and multivariate Logistic regression, univariate and multivariate Cox proportional risk regression were used for further analysis, survival curve was drawn. Through bioinformatics analysis, OSCC patients with higher expression of COL11A1 have poor overall survival compare with OSCC patients with lower expression of COL11A1 (hazard ratios [HR] = 1.32, P = .047). Pearson chi-square test showed that age (P = .011), tumor grade (P = .023), COL11A1 (P < .001) was significantly correlated with prognosis of OSCC. Univariate Logistic regression analysis showed age (odds ratio [OR] = 2.102, 95% confidence intervals [95%CI]: 1.180-3.746, P = .012), tumor grade (OR = 1.919, 95%CI: 1.093-3.372, P = .023) and COL11A1 (OR = 12.775, 95%CI: 6.509-25.071, P < .001). Multivariate Logistic regression analysis showed that COL11A1 (OR = 12.066, 95%CI: 6.042-24.096, P < .001) was significantly associated with prognosis of patients with OSCC. Univariate Cox regression analysis showed that age (HR = 1.592, 95%CI: 1.150-2.205, P = .005), tumor grade (HR = 1.460, 95%CI: 1.067-1.999, P = .018) and COL11A1 (HR = 1.848, 95%CI: 1.340-2.548, P < .001) were significantly correlated with survival time of OSCC patients. Multivariate Cox regression analysis showed that tumor grade (HR = 1.466, 95%CI: 1.064-2.020, P = .019) and COL11A1 (HR = 1.645, 95%CI: 1.164-2.325, P = .005) were significantly correlated with survival time of OSCC patients. COL11A1 is significantly correlated with occurrence of OSCC. When COL11A1 is highly expressed, prognosis of patients with OSCC is worse and the survival time is shorter.

Corneodesmosin as a potential target of oral squamous cell carcinoma

OBJECTIVE

The relationship between oral squamous cell carcinoma (OSCC) and Corneodesmosin (CDSN) remains unclear. This study aims to explore the correlation between CDSN and the prognosis and survival time of patients with OSCC.

METHODS

Bioinformatics were used to identify the hub role of CDSN in the OSCC. A total of 200 patients with OSCC were recruited. Clinical and follow-up data were recorded, and the expression level of CDSN was detected. Pearson chi-square test and Spearman correlation coefficient were used to analyze the relationship between prognosis and related parameters in patients with OSCC. Univariate and multivariate Logistic regression and Cox proportional risk regression were applied for further analysis, and receiver operating characteristic curve and survival curve of subjects were plotted.

RESULTS

CDSN was identified as the most significant hub gene of the OSCC by the cytoHubba. By the comparative toxicogenomics database (CTD) analysis, there was strong relationship between the CDSN and mouth neoplasms, head and neck neoplasms, squamous cell carcinoma of head and neck. The OSCC patients with low expression level of CDSN have poor overall survival compared with the high expression level of CDSN (HR = 0.75, 95% confidence interval [95%CI]: 0.57-0.98, P = .036). Spearman correlation coefficient analysis showed that CDSN expression level was significantly correlated with prognosis (ρ = -0.528, P < .001). Multivariate Logistic regression analysis showed that poor prognosis (odds ratio [OR] = 0.096, 95%CI: 0.049-0.189, P < .001) was significantly associated with low expression of CDSN. Cox regression analysis showed that the survival time of OSCC patients was shorter when CDSN expression was low (HR = 0.588, 95%CI: 0.420-0.823, P = .002). Strong predictive value of CDSN for the OSCC survival time was obtained by the biological process (BP)-neural network and support vector machine (SVM).

CONCLUSION

CDSN was significantly correlated with OSCC, and the shorter the survival time of patients with OSCC was, the worse the prognosis was.

KDM3A promotes oral squamous cell carcinoma cell proliferation and invasion via H3K9me2 demethylation-activated DCLK1

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a frequently-diagnosed malignancy with high potential for proliferation and invasion. Histone methylation is known as a crucial mechanism that regulates pathological processes in various cancers, including OSCC.

OBJECTIVE

This study sought to delve into the molecular mechanism of lysine demethylase 3 A (KDM3A) in OSCC cell proliferation and invasion.

METHODS

Expression levels of KDM3A, lysin-9 of di-methylated histone H3 (H3K9me2), and doublecortin-like kinase 1 (DCLK1) in cells were determined by reverse-transcription quantitative polymerase chain reaction or Western blot analysis. Cell proliferation and invasion were evaluated by cell counting kit-8, colony formation, and Transwell assays. The enrichment of KDM3A and H3K9me2 on the DCLK1 promoter was determined by chromatin immunoprecipitation assay. The functional rescue experiment was performed with DCLK1 overexpression vector and si-KDM3A in CAL-27 and SCC-9 cells.

RESULTS

KDM3A was elevated in OSCC cells. KDM3A knockdown suppressed OSCC proliferation and invasion, along with increased H3K9me2 level in OSCC cells. KDM3A and H3K9me2 were enriched on the DCLK1 promoter and inhibiting H3K9me2 improved DCLK1 expression levels. DCLK1 overexpression neutralized the inhibition of KDM3A knockdown on OSCC proliferation and invasion.

CONCLUSIONS

KDM3A facilitated OSCC proliferation and invasion by eliminating H3K9me2 to upregulate DCLK1 expression levels.

LncRNA DLEU1 facilitates the progression of oral squamous cell carcinoma by miR-126-5p/GAB1 axis

Oral squamous cell carcinoma (OSCC) is one of the most frequent malignancies found in head and neck cancers. Dysregulation of lncRNAs has been proposed to be related to the development of OSCC. Here, we investigated the function and probable mechanisms of lncRNA DLEU1 in OSCC. OSCC cell lines and human oral keratinocytes (HOKs) were cultured, while SCC-25 and CAL-27 cells were transfected with the corresponding plasmids. Reverse transcription quantitative PCR (RT-qPCR) and western blot were carried out to measure the RNA and protein levels. Cell proliferation, migration and invasion were evaluated using MTT assays, wound healing and Transwell assays. The StarBase database predicted the interactions between DLEU1 and miR-126-5p, as well as miR-126-5p and GAB1, which were further validated using a dual-luciferase reporter assay. Our results indicated that DLEU1 and GAB1 were upregulated, while miR-126-5p was downregulated in OSCC cells. Silencing DLEU1 reduced OSCC cell proliferation, migration, and invasion, while DLEU1 overexpression had the opposite effects. DLEU1 mediated biological effects in OSCC through binding to miR-126-5p, which directly targeted GAB1. miR-126-5p knockdown rescued the inhibitory function of DLEU1 depletion on proliferation, migration and invasion. Meanwhile, the miR-126-5p mimic exerted suppressive functions in the progression of OSCC, which were neutralized after GAB1 overexpression. In summary, lncRNA DLEU1 targets the miR-126-5p/GAB1 axis to aggravate OSCC progression, providing a novel target for treating OSCC.

Stabilization of the c-Myc Protein via the Modulation of Threonine 58 and Serine 62 Phosphorylation by the Disulfiram/Copper Complex in Oral Cancer Cells

MYC has a short half-life that is tightly regulated through phosphorylation and proteasomal degradation. Many studies have claimed that treatment with disulfiram (DSF) with or without copper ions can cause cancer cell death in a reactive oxygen species (ROS)-dependent manner in cancer cells. Our previous study showed that the levels of c-Myc protein and the phosphorylation of threonine 58 (T58) and serine 62 (S62) increased in DSF-Cu-complex-treated oral epidermoid carcinoma Meng-1 (OECM-1) cells. These abovementioned patterns were suppressed by pretreatment with an ROS scavenger, N-acetyl cysteine. The overexpression of c-Myc failed to induce hypoxia-inducible factor 1α protein expression, which was stabilized by the DSF-Cu complex. In this study, we further examined the regulatory mechanism behind the induction of the c-Myc of the DSF-Cu complex in an OECM-1 cell compared with a Smulow–Glickman (SG) human normal gingival epithelial cell. Our data showed that the downregulation of c-Myc truncated nick and p62 and the induction of the ratio of H3P/H3 and p-ERK/ERK might not be involved in the increase in the amount of c-Myc via the DSF/copper complexes in OECM-1 cells. Combined with the inhibitors for various signaling pathways and cycloheximde treatment, the increase in the amount of c-Myc with the DSF/copper complexes might be mediated through the increase in the stabilities of c-Myc (T58) and c-Myc (S62) proteins in OECM-1 cells. In SG cells, only the c-Myc (T58) protein was stabilized by the DSF-Cu (I and II) complexes. Hence, our findings could provide novel regulatory insights into the phosphorylation-dependent stability of c-Myc in DSF/copper-complex-treated oral squamous cell carcinoma.

Liquid Biopsy and Circulating Biomarkers for the Diagnosis of Precancerous and Cancerous Oral Lesions

Oral cancer is one of the most common malignancies worldwide, accounting for 2% of all cases annually and 1.8% of all cancer deaths. To date, tissue biopsy and histopathological analyses are the gold standard methods for the diagnosis of oral cancers. However, oral cancer is generally diagnosed at advanced stages with a consequent poor 5-year survival (~50%) due to limited screening programs and inefficient physical examination strategies. To address these limitations, liquid biopsy is recently emerging as a novel minimally invasive tool for the early identification of tumors as well as for the evaluation of tumor heterogeneity and prognosis of patients. Several studies have demonstrated that liquid biopsy in oral cancer could be useful for the detection of circulating biomarkers including circulating tumor DNA (ctDNA), microRNAs (miRNAs), proteins, and exosomes, thus improving diagnostic strategies and paving the way to personalized medicine. However, the application of liquid biopsy in oral cancer is still limited and further studies are needed to better clarify its clinical impact. The present manuscript aims to provide an updated overview of the potential use of liquid biopsy as an additional tool for the management of oral lesions by describing the available methodologies and the most promising biomarkers.

Metabolomic Analysis Reveals that SPHK1 Promotes Oral Squamous Cell Carcinoma Progression through NF-κB Activation

BACKGROUND

Metabolic disorders are significant in the occurrence and development of malignant tumors. Changes of specific metabolites and metabolic pathways are molecular therapeutic targets. This study aims to determine the metabolic differences between oral squamous cell carcinoma (OSCC) tissues and paired adjacent noncancerous tissues (ANT) through liquid chromatography-mass spectrometry (LC-MS). SPHK1 is a key enzyme in sphingolipid metabolism. This study also investigates the potential role of SPHK1 in OSCC.

MATERIALS AND METHODS

This study used LC-MS to analyze metabolic differences between OSCC tissues and paired ANT. Principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) were applied to explain the significance of phospholipid metabolism pathways in the occurrence and development of OSCC. Through further experiments, we confirmed the oncogenic phenotypes of SPHK1 in vitro and in vivo, including proliferation, migration, and invasion.

RESULTS

The sphingolipid metabolic pathway was significantly activated in OSCC, and the key enzyme SPHK1 was significantly upregulated in oral cancer tissues, predicting poor OSCC prognosis. In this study, SPHK1 overexpression was associated with high-grade malignancy and poor OSCC prognosis. SPHK1 targeted NF-κB by facilitating p65 expression to regulate OSCC tumor progression and promote metastasis.

CONCLUSIONS

This study identified metabolic differences between OSCC and paired ANT, explored the carcinogenic role of overexpressed SPHK1, and revealed the association of SPHK1 with poor OSCC prognosis. SPHK1 targets NF-κB signaling by facilitating p65 expression to regulate tumor progression and promote tumor metastasis, providing potential therapeutic targets for diagnosing and treating oral tumors.

Current and Future Biomarkers for Immune Checkpoint Inhibitors in Head and Neck Squamous Cell Carcinoma

With the introduction of immunotherapy, significant improvement has been made in the treatment of head and neck squamous cell carcinoma (HNSCC). However, only a small subset of patients with HNSCC benefit from immunotherapy. The current biomarker, a programmed cell death protein ligand 1 (PD-L1) expression that is widely used in treatment decision making for advanced HNSCC, has only a moderate predictive value. Additionally, PD-L1-based assay has critical inherent limitations due to its highly dynamic nature and lack of standardization. With the advance in molecular techniques and our understanding of biology, more reliable, reproducible, and practical novel biomarkers are being developed. These include but are not limited to neoantigen/mutation characteristics, immune transcriptomes, tumor-infiltrating immune cell composition, cancer epigenomic, proteomics and metabolic characteristics, and plasma-based and organoid assays.

MIR4435-2HG：A tumor-associated long non-coding RNA

BACKGROUND

It is well known that the changes in the expression level of LncRNA can affect the progression of tumors, which has caused a great upsurge of research in recent years. More and more LncRNA has been proved to take effect on a series of cancers and can promote tumor growth, migration and invasion. In this review, we aim to clarify the pathophysiological functions of LncRNA -MIR4435-2 HG in multiple tumors can be elucidated.

METHODS

By consulting the literature through PubMed, this paper summarizes the relationship between MIR4435-2HG and tumor and its role in the occurrence and development of cancer, and also expounds the specific molecular mechanism of the effect of MIR4435-2HG on cancer.

RESULTS

MIR4435-2HG can function as an oncogene in a variety of cancers. The expression level was abnormally elevated in a series of cancers, consisting of melanoma gastric cancer, head and neck squamous cell carcinoma, oral squamous cell carcinoma, lung cancer, cervical cancer, prostate carcinoma, ovarian cancer, breast cancer, hepatocellular Carcinoma, clear cell renal cell carcinoma malignant, glioma and colorectal cancer. Moreover, MIR4435-2HG is related to the poor prognosis of a variety of cancers. MIR4435-2HG can also affect tumor proliferation, invasion and apoptosis. In addition, MIR4435-2HG can also enhance the metabolic function of myeloid dendritic cells of elite HIV-1 controllers.

CONCLUSION

MIR4435-2HG affects the development of a variety of cancers. It can act as a clinical marker for early tumor diagnosis and takes effects to tumor targeted therapy.

Mechanism of METTL14 and m6A modification of lncRNA MALAT1 in the proliferation of oral squamous cell carcinoma cells

OBJECTIVES

Methyltransferase-like 14 (METTL14) plays an epigenetic role in various cancer through N6-methyladenosine (m6A) modification. This study sought to analyze the mechanism of METTL14 in oral squamous cell carcinoma (OSCC) cell proliferation.

METHODS

Expression levels of METTL14, lncRNA metastasis associated with lung adenocarcinoma transcript 1 (lncRNA MALAT1), microRNA (miR)-224-5p, and histone lysine demethylase 2A (KDM2A) in OSCC tissues (N = 40), and cell lines (FaDu, SCC-25, CAL-27, and SCC-15) were detected. Cell viability and colony formation capacity were assessed. m6A level, stability, and subcellular localization of lncRNA MALAT1 were determined. Nude mouse xenograft tumor assay was performed to confirm the role of METTL14 in vivo.

RESULTS

METTL14 and lncRNA MALAT1 were upregulated, and miR-224-5p was downregulated in OSCC tissues and cells. Silencing METTL14 repressed OSCC cell viability and colony formation. Overexpression of MALAT1 and KDM2A or miR-224-5p downregulation reversed the inhibition of silencing METTL14 on OSCC cell proliferation. METTL14 induced m6A modification of MALAT1 to upregulate MALAT1. MALAT1 is comparatively bound to miR-224-5p to promote KDM2A transcription. In vivo, METTL14 promoted tumor growth via regulating MALAT1/miR-224-5p/ KDM2A.

CONCLUSIONS

Overall, our findings verified the therapeutic role of silencing METTL14 in OSCC treatment through the MALAT1/miR-224-5p/KDM2A axis.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Prognostic significance of a 4-lncRNA glycolysis-related signature in oral squamous cell carcinoma

BACKGROUND/PURPOSE

Oral squamous cell carcinoma (OSCC) is a highly malignant tumor, and the overall survival (OS) time of patients with OSCC varies considerably. This study aimed to identify reliable biomarkers for OSCC and construct a new prognostic signature, which may guide personalized precision treatment.

MATERIALS AND METHODS

Transcriptome array data of 317 patients with OSCC from The Cancer Genome Atlas Project (TCGA) cohort were retrospectively analyzed. Single-sample gene set enrichment analysis (ssGSEA) and univariate Cox regression were performed to identify the prognostic significance of the hallmarks of each tumor in OSCC. Subsequently, lncRNAs related to glycolysis were identified through co-expression analysis. A glycolysis-related prognostic signature was constructed by combining univariate Cox regression, least absolute shrinkage and selection operator (Lasso) regression, and multivariate Cox regression analyses. Additionally, the infiltration of immune cells in OSCC was evaluated based on data from ssGSEA and TIMER databases.

RESULTS

Glycolysis was identified as the main risk factor for OS in a variety of cancer hallmarks. The 4-lncRNA glycolysis prognostic signature could distinguish high and low-risk patients. This risk signature was found to be an independent prognostic risk factor for OSCC, showing good predictive power compared with other clinicopathological indicators. Immune correlation analysis showed that patients in the low-risk group exhibited higher levels of immune cell infiltration.

CONCLUSION

The novel 4-lncRNA prognostic signature can predict the clinical outcome of patients with OSCC well, and it is expected to become a promising prognostic biomarker as well as a potential therapeutic target in the future.

Finding the combination of multiple biomarkers to diagnose oral squamous cell carcinoma - A data mining approach

Data mining has proven to be a reliable method to analyze and discover useful knowledge about various diseases, including cancer research. In particular, data mining and machine learning algorithms to study oral squamous cell carcinoma (OSCC), the most common form of oral cancer, is a new area of research. This malignant neoplasm can be studied using saliva samples. Saliva is an important biofluid that must be used to verify potential biomarkers associated with oral cancer. In this study, first, we provide an overview of OSSC diagnoses based on machine learning and salivary metabolites. To our knowledge, this is the first study to apply advanced data mining techniques to diagnose OSCC. Then, we give new results of classification and feature selection algorithms used to identify potential salivary biomarkers of OSCC. To accomplish this task, we used the filter feature selection random forest importance algorithm and a wrapper methodology to evaluate the importance of metabolites obtained from gas chromatography mass-spectrometry (GC-MS) in the context of differentiation of OSCC and the control group. Salivary samples (n = 68) were collected for the control group, and the OSCC group were from patients matched for gender, age, and smoking habit. The classification process occurred based on Random Forest (RF) classification algorithm along with 10-cross validation. The results showed that glucuronic acid, maleic acid, and batyl alcohol can classify the samples with an area under the curve (AUC) of 0.91 versus an AUC of 0.76 using all 51 metabolites analyzed. The methodology used in this study can assist healthcare professionals and be adopted to discover diagnostic biomarkers for other diseases.

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

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

PKM2 Modulation in Head and Neck Squamous Cell Carcinoma

The enzyme pyruvate kinase M2 (PKM2) plays a major role in the switch of tumor cells from oxidative phosphorylation to aerobic glycolysis, one of the hallmarks of cancer. Different allosteric inhibitors or activators and several posttranslational modifications regulate its activity. Head and neck squamous cell carcinoma (HNSCC) is a common disease with a high rate of recurrence. To find out more about PKM2 and its modulation in HNSCC, we examined a panel of HNSCC cells using real-time cell metabolic analysis and Western blotting with an emphasis on phosphorylation variant Tyr105 and two reagents known to impair PKM2 activity. Our results show that in HNSCC, PKM2 is commonly phosphorylated at Tyrosine 105. Its levels depended on tyrosine kinase activity, emphasizing the importance of growth factors such as EGF (epidermal growth factor) on HNSCC metabolism. Furthermore, its correlation with the expression of CD44 indicates a role in cancer stemness. Cells generally reacted with higher glycolysis to PKM2 activator DASA-58 and lower glycolysis to PKM2 inhibitor Compound 3k, but some were more susceptible to activation and others to inhibition. Our findings emphasize the need to further investigate the role of PKM2 in HNSCC, as it could aid understanding and treatment of the disease.

Identification of Possible Salivary Metabolic Biomarkers and Altered Metabolic Pathways in South American Patients Diagnosed with Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) represents 90% of oral malignant neoplasms. The search for specific biomarkers for OSCC is a very active field of research contributing to establishing early diagnostic methods and unraveling underlying pathogenic mechanisms. In this work we investigated the salivary metabolites and the metabolic pathways of OSCC aiming find possible biomarkers. Salivary metabolites samples from 27 OSCC patients and 41 control individuals were compared through a gas chromatography coupled to a mass spectrometer (GC-MS) technique. Our results allowed identification of pathways of the malate-aspartate shuttle, the beta-alanine metabolism, and the Warburg effect. The possible salivary biomarkers were identified using the area under receiver-operating curve (AUC) criterion. Twenty-four metabolites were identified with AUC > 0.8. Using the threshold of AUC = 0.9 we find malic acid, maltose, protocatechuic acid, lactose, 2-ketoadipic, and catechol metabolites expressed. We notice that this is the first report of salivary metabolome in South American oral cancer patients, to the best of our knowledge. Our findings regarding these metabolic changes are important in discovering salivary biomarkers of OSCC patients. However, additional work needs to be performed considering larger populations to validate our results.

Identification of a Transcriptional Prognostic Signature From Five Metabolic Pathways in Oral Squamous Cell Carcinoma

Dysregulated metabolic pathways have been appreciated to be intimately associated with tumorigenesis and patient prognosis. Here, we sought to develop a novel prognostic signature based on metabolic pathways in patients with primary oral squamous cell carcinoma (OSCC). The original RNA-seq data of OSCC from The Cancer Genome Atlas (TCGA) project and Gene Expression Omnibus (GEO) database were transformed into a metabolic pathway enrichment score matrix by single-sample gene set enrichment analysis (ssGSEA). A novel prognostic signature based on metabolic pathways was constructed by LASSO and stepwise Cox regression analysis in the training cohort and validated in both testing and validation cohorts. The optimal cut-off value was obtained using the Youden index by receiver operating characteristic (ROC) curve. The overall survival curves were plotted by the Kaplan-Meier method. A time-dependent ROC curve analysis with 1, 3, 5 years as the defining point was performed to evaluate the predictive value of this prognostic signature. A 5-metabolic pathways prognostic signature (5MPS) for OSCC was constructed which stratified patients into subgroups with favorable or inferior survival. It served as an independent prognostic factor for patient survival and had a satisfactory predictive performance for OSCC. Our results developed a novel prognostic signature based on dysregulated metabolic pathways in OSCC and provided support for aberrant metabolism underlying OSCC tumorigenesis.