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BACKGROUND: Oral potentially malignant disorders (OPMDs) occur in up to 4%-5% of the population, of which oral leukoplakia (OL) is the most common subtype. Predicting high-risk OL remains a challenge. Early diagnosis and effective treatment are thought to be of paramount importance to improve outcomes. METHODS: We searched PubMed and Clinicaltrials.gov data for updates in the clinical management of OL from 2015 to current. RESULTS: Recent publication of large cohorts of patients with OL aids in counseling patients regarding risk of malignant transformation. Management for OL includes surveillance, excision, and laser surgery, as well as local and systemic approaches to chemoprevention. Several new entities show promise regarding candidate biomarkers, chemoprevention agents, and diagnostic adjuncts, though all require further validation. CONCLUSION: This update serves to further inform clinical management of OL and provide impetus for future investigations. TRIAL REGISTRATION: NCT00099021, NCT00951379, NCT05727761, NCT05727761.

Introduction: Murine tumor growth restriction by neem leaf glycoprotein (NLGP) was established in various transplanted models of murine sarcoma, melanoma and carcinoma. However, the role of NLGP in the sequential carcinogenic steps has not been explored. Thus, tongue carcinogenesis in Swiss mice was induced by 4-nitroquinoline-1-oxide (4NQO), which has close resemblance to human carcinogenesis process. Interventional role of NLGP in initiation-promotion protocol established during 4NQO mediated tongue carcinogenesis in relation to systemic immune alteration and epithelial-mesenchymal transition (EMT) is investigated. Methods: 4NQO was painted on tongue of Swiss mice every third day at a dose of 25µl of 5mg/ml stock solution. After three consecutive treatments with 4NQO (starting Day7), one group of mice was treated with NLGP (s.c. 25μg/mice/week), keeping a group as PBS control. Mice were sacrificed in different time-intervals to harvest tongues and studied using histology, immunohistochemistry, flow-cytometry and RT-PCR on different immune cells and EMT markers (e-cadherin, vimentin) to elucidate their phenotypic and secretory status. Results: Local administration of 4NQO for consecutive 300 days promotes significant alteration in tongue mucosa including erosion in papillae and migration of malignant epithelial cells to the underlying connective tissue stroma with the formation of cell nests (exophytic-hyperkeratosis with mild dysplasia). Therapeutic NLGP treatment delayed pre-neoplastic changes promoting normalization of mucosa by maintaining normal structure. Flow-cytometric evidences suggest that NLGP treatment upregulated CD8+, IFNγ+, granzyme B+, CD11c+ cells in comparison to 4NQO treated mice with a decrease in Ki67+ and CD4+FoxP3+ cells in NLGP treated cohort. RT-PCR demonstrated a marked reduction of MMP9, IL-6, IL-2, CD31 and an upregulation in CCR5 in tongues from 4NQO+NLGP treated mice in comparison to 4NQO treated group. Moreover, 4NQO mediated changes were associated with reduction of e-cadherin and simultaneous up-regulation of vimentin expression in epithelium that was partially reversed by NLGP. Discussion: Efficacy of NLGP was tested first time in sequential carcinogenesis model and proved effective in delaying the initial progression. NLGP normalizes type 1 immunity including activation of the CD8+T effector functions, reduction of regulatory T cell functions, along with changes in EMT to make the host systemically alert to combat the carcinogenic threat. Topical application of 4NQO on mouse tongues enhances carcinogenic events, like, angiogenesis, proliferation and epithelial-mesenchymal transition, along with invasive properties. Therapeutic application of Neem Leaf Glycoprotein (NLGP) hinders preneoplastic events and delays carcinogenesis. Immunological study deciphers the role of augmented CD8+T cells and lowered Treg population finally acting on Notch1-Stat3 pathway leading to the restriction in carcinogenesis. [ABSTRACT FROM AUTHOR]

• mCAFs shaped the COL18high COL5high collagen landscape in OSCC. • OSCC-derived EVs educate fibroblasts to COL18+ COL5+ mCAFs. • OSCC-derived EVs promote tumor invasion and COL18high COL5high matrix deposition. • TGF-β1 in EVs educate mCAFs via TGF-β1/Smad3 signaling pathway. • TGF-β1 in EVs promotes tumor progression and COL18high COL5high matrix deposition. Cancer-associated myofibroblasts (mCAFs) represent a significant component of the tumor microenvironment due to their contributions to extracellular matrix (ECM) remodeling. The pro-tumor mechanisms of extracellular vesicles (EVs) by regulating mCAFs and related collagens remain poorly understood in oral squamous cell carcinoma (OSCC). In this study, through analysis of single-cell sequencing data and immunofluorescence staining, we confirmed the increased presence of mCAFs and enrichment of specific collagen types in OSCC tissues. Furthermore, we demonstrated that OSCC-derived EVs promote the transformation of fibroblasts into mCAFs, leading to tumor invasion. Proteomic analysis identified the presence of TGF-β1 in EVs and revealed its role in inducing mCAFs via the TGF-β1/SMAD signaling pathway. Experiments in vivo confirmed that EVs, particularly those carrying TGF-β1, trigger COL18high COL5high matrix deposition, thereby forming the pro-tumor ECM in OSCC. In summary, our investigation unveils the significant involvement of OSCC-derived EVs in orchestrating the differentiation of fibroblasts into mCAFs and modulating specific collagen types within the ECM. Therefore, this study provides a theoretical basis for targeting the EV-mediated TGF-β1 signaling pathway as a potential therapeutic strategy for OSCC. [ABSTRACT FROM AUTHOR]

Yohimbine is a potent bioactive indole alkaloid, isolated from a variety of biological sources and has long been used as a natural stimulant and aphrodisiac, particularly to treat erectile dysfunction. However, some literature also points toward its anticancer effect in different experimental models. The current study aimed to address a clinical concern on the therapeutic utilization of yohimbine as a repurposed drug. We employed 7,12‐dimethylbenz[a]anthracene (DMBA)‐induced hamster buccal pouch carcinogenesis model juxtaposed with biochemical investigation of several detoxification and antioxidant markers, such as Cyt p450, Cyt b5, thiobarbituric acid reactive substance (TBARS), glutathione (GSH), glutathione reductase (GR), glutathione S transferase (GST), DT‐diaphorase, vitamin C, vitamin E, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). The immunohistochemical assessment of cyclooxygenase‐2 (COX‐2), interleukin‐6 (IL‐6), proliferating cell nuclear antigen (PCNA), and cyclin D1 expression were also performed to observe the effect of yohimbine on these markers. The hamsters treated with DMBA presented the growth of tumors in the buccal pouches, accompanied by significant changes in the liver and buccal mucosa levels of Phase I & II detoxification enzymes and lipid peroxidation (LPO). A significant rise in the range of 2‐ to 3.5‐fold was observed in Cyt p450, Cyt b5, and LPO in DMBA‐treated animals. However, oral administration of yohimbine significantly restored the LPO, antioxidant, and detoxifying enzyme activities. Additionally, the levels of COX‐2, IL‐6, PCNA, and cyclin D1 were also found to be downregulated by yohimbine treatment. In conclusion, yohimbine improved the biochemical and immunohistochemical markers of DMBA‐induced oral cancer and reverted to near normal values via ameliorating the underlying inflammation and oxidative stress conditions. Our study highlighted the potential of yohimbine as anticancer agent, especially against oral cancer and suggested its possible use as repurposed drug. Summary: In this study, we have used hamster model to evaluate potential of yohimbine against oral carcinogenesis.Yohimbine reinstated DMBA‐induced oral carcinogenesis and facilitated detoxification by modulating the Phase I and Phase II enzyme activities.The upregulated expression of Cox‐2, IL‐6, PCNA, and cyclin D1 was also found to be reverted to near normal by yohimbine treatment. [ABSTRACT FROM AUTHOR]

Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer, which is usually preceded by a potentially malignant disorder histologically diagnosed as dysplasia. We and others have provided evidence for the pro-carcinogenic role of the Wnt/β-catenin pathway in this context, in which Wnt ligands stabilize and allow relocalization of β-catenin to the nucleus for transcription of pro-survival and pro-proliferation genes. However, the contribution of Porcupine (PORCN), an O-acyltransferase that catalyzes the palmitoylation of Wnt ligands, to OSCC carcinogenesis is not known. Moreover, the effectiveness of LGK974, a novel PORCN inhibitor remains to be elucidated. By using different ex vivo, in vivo and in vitro OSCC carcinogenesis models, we show that PORCN expression is significantly increased in high-grade dysplasia as well as moderately/poorly- differentiated OSCC. Consistent with these observations, expression of key proteins involved in the Wnt/β-catenin pathway are elevated as well. Importantly, the treatment with LGK974, a chemical PORCN inhibitor, reduced the number and size of oral lesions in mice treated with 4-Nitroquinoline 1-oxide (4NQO), a tobacco smoke surrogate. These results highlight the role of PORCN during OSCC carcinogenesis.

The correction notice in the journal "Frontiers in Immunology" addresses an error in the legend for Figures 1 and 2 in the article on the immunomodulatory impact of neem leaf glycoprotein on oral carcinogenesis. The corrected legends provide detailed information on the maintenance of tongue features and body weight changes during the study. Additionally, a correction has been made to the Abstract and Methods section regarding the treatment protocol. The authors assure that these errors do not affect the scientific conclusions of the article. [Extracted from the article]

Let-7b and miRNA-96 are among the dysregulated microRNAs in various diseases. Selected seventy-five male rats were divided into five equal treatment groups and were given 4-nitroquinoline 1-oxide (4-NQO) by drinking water (50 ppm) for five different drenching periods. To each treatment group, a control group of five males was also assigned. The oral pathological changes were microscopically evaluated thereafter. Histopathological changes indicating dysplasia or frank carcinoma were observed in the fifth treatment group only. Let-7b and miRNA-96 expressions in the tongue tissue and serum were quantified using quantitative reverse transcription PCR (qRT-PCR). The fifth treatment group only showed signs of severe and well differentiated squamous cell carcinoma in percentages of 40% and 26.7%, respectively. Let-7b expression appeared to be statistically non-significantly different when up and downregulation were compared in tissue and serum samples (p=.3; p=.08). For miRNA-96, it seemed that no statistically significant difference (p=.08) was attained when tissue samples were studied, while the difference was statistically significant (p=.04) when serum samples were considered. Let-7b can be considered a good biomarker for oral squamous cell carcinoma (OSCC) in tissue and body fluid as well, while miRNA-96 demonstrated a controversial result as far as the tissue type was considered and, thus, can play the role of an oncogene (OG) or a tumor suppressor gene (TS). [ABSTRACT FROM AUTHOR]

Oral squamous cell carcinoma (OSCC) stands as a predominant and perilous malignant neoplasm globally, with the majority of cases originating from oral potential malignant disorders (OPMDs). Despite this, effective strategies to impede the progression of OPMDs to OSCC remain elusive. In this study, we established mouse models of oral carcinogenesis via 4‐nitroquinoline 1‐oxide induction, mirroring the sequential transformation from normal oral mucosa to OPMDs, culminating in OSCC development. By intervening during the OPMDs stage, we observed that combining PD1 blockade with photodynamic therapy (PDT) significantly mitigated oral carcinogenesis progression. Single‐cell transcriptomic sequencing unveiled microenvironmental dysregulation occurring predominantly from OPMDs to OSCC stages, fostering a tumor‐promoting milieu characterized by increased Treg proportion, heightened S100A8 expression, and decreased Fib_Igfbp5 (a specific fibroblast subtype) proportion, among others. Notably, intervening with PD1 blockade and PDT during the OPMDs stage hindered the formation of the tumor‐promoting microenvironment, resulting in decreased Treg proportion, reduced S100A8 expression, and increased Fib_Igfbp5 proportion. Moreover, combination therapy elicited a more robust treatment‐associated immune response compared with monotherapy. In essence, our findings present a novel strategy for curtailing the progression of oral carcinogenesis. [ABSTRACT FROM AUTHOR]

Although oxidative stress is closely associated with tumor invasion and metastasis, its’ exact role and mechanism in the initial stage of oral cancer remain ambiguous. Glutamine uptake mediated by alanine-serine-cysteine transporter 2 (ASCT2) participates in glutathione synthesis to resolve oxidative stress. Currently, we firstly found that ASCT2 deletion caused oxidative stress in oral mucosa and promoted oral carcinogenesis induced by 4-Nitroquinoline-1-oxide (4-NQO) using transgenic mice of ASCT2 knockout in oral epithelium. Subsequently, we identified an upregulated gene Thbs1 linked to macrophage infiltration by mRNA sequencing and immunohistochemistry. Importantly, multiplex immunohistochemistry showed M1-like tumor-associated macrophages (TAMs) were enriched in cancerous area. Mechanically, targeted ASCT2 effectively curbed glutamine uptake and caused intracellular reactive oxygen species (ROS) accumulation, which upregulated Thbs1 in oral keratinocytes and then activated p38, Akt and SAPK/JNK signaling to polarize M1-like TAMs via exosome-transferred pathway. Moreover, we demonstrated M1-like TAMs promoted malignant progression of oral squamous cell carcinoma (OSCC) both in vitro and in vivo by a DOK transformed cell line induced by 4-NQO. All these results establish that oxidative stress triggered by ASCT2 deletion promotes oral carcinogenesis through Thbs1-mediated M1 polarization, and indicate that restore redox homeostasis is a new approach to prevent malignant progression of oral potentially malignant disorders.

Oral tongue squamous cell carcinoma (OTSCC) is the most common cancer of the oral cavity and is associated with high morbidity due to local invasion and lymph node metastasis. Tumor infiltrating lymphocytes (TILs) are associated with good prognosis in oral cancer patients and dictate response to treatment. Ectopic sites for immune activation in tumors, known as tertiary lymphoid structures (TLS), and tumor-associated high-endothelial venules (TA-HEVs), which are specialized lymphocyte recruiting vessels, are associated with a favorable prognosis in OSCC. Why only some tumors support the development of TLS and HEVs is poorly understood. In the current study we explored the infiltration of lymphocyte subsets and the development of TLS and HEVs in oral epithelial lesions using the 4-nitroquinoline 1-oxide (4NQO)- induced mouse model of oral carcinogenesis. We found that the immune response to 4NQO-induced oral epithelial lesions was dominated by T cell subsets. The number of T cells (CD4+, FoxP3+, and CD8+), B cells (B220+) and PNAd+ HEVs increased from the earliest to the latest endpoints. All the immune markers increased with the severity of the dysplasia, while the number of HEVs and B cells further increased in SCCs. HEVs were present already in early-stage lesions, while TLS did not develop at any timepoint. This suggests that the 4NQO model is applicable to study the dynamics of the tumor immune microenvironment at early phases of oral cancer development, including the regulation of TA-HEVs in OTSCC. [ABSTRACT FROM AUTHOR]

Abstract Oral squamous cell carcinoma (OSCC) stands as a predominant and perilous malignant neoplasm globally, with the majority of cases originating from oral potential malignant disorders (OPMDs). Despite this, effective strategies to impede the progression of OPMDs to OSCC remain elusive. In this study, we established mouse models of oral carcinogenesis via 4‐nitroquinoline 1‐oxide induction, mirroring the sequential transformation from normal oral mucosa to OPMDs, culminating in OSCC development. By intervening during the OPMDs stage, we observed that combining PD1 blockade with photodynamic therapy (PDT) significantly mitigated oral carcinogenesis progression. Single‐cell transcriptomic sequencing unveiled microenvironmental dysregulation occurring predominantly from OPMDs to OSCC stages, fostering a tumor‐promoting milieu characterized by increased Treg proportion, heightened S100A8 expression, and decreased Fib_Igfbp5 (a specific fibroblast subtype) proportion, among others. Notably, intervening with PD1 blockade and PDT during the OPMDs stage hindered the formation of the tumor‐promoting microenvironment, resulting in decreased Treg proportion, reduced S100A8 expression, and increased Fib_Igfbp5 proportion. Moreover, combination therapy elicited a more robust treatment‐associated immune response compared with monotherapy. In essence, our findings present a novel strategy for curtailing the progression of oral carcinogenesis.

Oral tongue squamous cell carcinoma (OTSCC) is the most common cancer of the oral cavity and is associated with high morbidity due to local invasion and lymph node metastasis. Tumor infiltrating lymphocytes (TILs) are associated with good prognosis in oral cancer patients and dictate response to treatment. Ectopic sites for immune activation in tumors, known as tertiary lymphoid structures (TLS), and tumor-associated high-endothelial venules (TA-HEVs), which are specialized lymphocyte recruiting vessels, are associated with a favorable prognosis in OSCC. Why only some tumors support the development of TLS and HEVs is poorly understood. In the current study we explored the infiltration of lymphocyte subsets and the development of TLS and HEVs in oral epithelial lesions using the 4-nitroquinoline 1-oxide (4NQO)-induced mouse model of oral carcinogenesis. We found that the immune response to 4NQO-induced oral epithelial lesions was dominated by T cell subsets. The number of T cells (CD4+, FoxP3+, and CD8+), B cells (B220+) and PNAd+ HEVs increased from the earliest to the latest endpoints. All the immune markers increased with the severity of the dysplasia, while the number of HEVs and B cells further increased in SCCs. HEVs were present already in early-stage lesions, while TLS did not develop at any timepoint. This suggests that the 4NQO model is applicable to study the dynamics of the tumor immune microenvironment at early phases of oral cancer development, including the regulation of TA-HEVs in OTSCC.

IntroductionMurine tumor growth restriction by neem leaf glycoprotein (NLGP) was established in various transplanted models of murine sarcoma, melanoma and carcinoma. However, the role of NLGP in the sequential carcinogenic steps has not been explored. Thus, tongue carcinogenesis in Swiss mice was induced by 4-nitroquinoline-1-oxide (4NQO), which has close resemblance to human carcinogenesis process. Interventional role of NLGP in initiation-promotion protocol established during 4NQO mediated tongue carcinogenesis in relation to systemic immune alteration and epithelial-mesenchymal transition (EMT) is investigated.Methods4NQO was painted on tongue of Swiss mice every third day at a dose of 25µl of 5mg/ml stock solution. After three consecutive treatments with 4NQO (starting Day7), one group of mice was treated with NLGP (s.c. 25μg/mice/week), keeping a group as PBS control. Mice were sacrificed in different time-intervals to harvest tongues and studied using histology, immunohistochemistry, flow-cytometry and RT-PCR on different immune cells and EMT markers (e-cadherin, vimentin) to elucidate their phenotypic and secretory status.ResultsLocal administration of 4NQO for consecutive 300 days promotes significant alteration in tongue mucosa including erosion in papillae and migration of malignant epithelial cells to the underlying connective tissue stroma with the formation of cell nests (exophytic-hyperkeratosis with mild dysplasia). Therapeutic NLGP treatment delayed pre-neoplastic changes promoting normalization of mucosa by maintaining normal structure. Flow-cytometric evidences suggest that NLGP treatment upregulated CD8+, IFNγ+, granzyme B+, CD11c+ cells in comparison to 4NQO treated mice with a decrease in Ki67+ and CD4+FoxP3+ cells in NLGP treated cohort. RT-PCR demonstrated a marked reduction of MMP9, IL-6, IL-2, CD31 and an upregulation in CCR5 in tongues from 4NQO+NLGP treated mice in comparison to 4NQO treated group. Moreover, 4NQO mediated changes were associated with reduction of e-cadherin and simultaneous up-regulation of vimentin expression in epithelium that was partially reversed by NLGP.DiscussionEfficacy of NLGP was tested first time in sequential carcinogenesis model and proved effective in delaying the initial progression. NLGP normalizes type 1 immunity including activation of the CD8+T effector functions, reduction of regulatory T cell functions, along with changes in EMT to make the host systemically alert to combat the carcinogenic threat.

This study aimed to determine the impact of low levels of alcohol consumption on the interaction of the oral cavity with Candida albicans , a species that is commonly found at higher levels in the oral cavities of regular alcohol consumers, patients with pre-malignant diseases, and patients with existing oral cancer (OC). The gingival squamous cell carcinoma cell line, Ca9-22, was subjected to low-level ethanol exposure before co-culture with heat-inactivated C. albicans (HICA). We performed cell viability assays, measured reactive oxygen species, and used Western blot analysis for cell death markers to examine the effect of ethanol and HICA on cells. Scratch assays and anchorage-independent growth assays were used to determine cell behavioral changes. The results showed that ethanol in combination with HICA exacerbated cell death and cell cycle disruption, delayed NF-κB signaling, increased TIMP-2 secretion, and subsequently decreased MMP-2 secretion when compared to exposure to HICA alone. Conversely, both ethanol and HICA independently increased proliferation of Ca9-22 cells in scratch assays, and in combination, increased their capacity for anchorage-independent growth. Low levels of ethanol may provide protective effects against Candida -induced inflammatory oral carcinogenesis or OC progression. • Alcohol delays and dampens the NF-κB immune response in Ca9-22 oral cancer cell line. • Alcohol increases expression of TIMP-2 and decreases MMP-2 secretion in Ca9-22 cells. • Alcohol and heat-inactivated C. albicans independently increase proliferation of Ca9-22 cells in scratch assays. • Alcohol in combination with heat-inactivated C. albicans increases anchorage-independent growth of Ca9-22 cells. [ABSTRACT FROM AUTHOR]

Objective: This study objective was to ascertain the drug biochanin A (BCA) impacts on the management of oral squamous cell carcinoma (OSCC) caused by the chemical 7,12-dimethylbenz[a]anthracene (DMBA) in male Syrian golden hamsters. Methods: The oral cancer was induced by the application of a DMBA (0.5 %) thrice a week for the duration of fourteen weeks in the buccal pouch. The study assessed various parameters, including volume, incidence, and burden of tumors within the hamsters' buccal pouches. Additionally, it employed colorimetric methods to measure the levels of carcinogen-detoxifying agents, lipid peroxidation, and antioxidant activity. The histopathological examination was assessed in the buccal tissues, as well. Results: The hamsters exposed to DMBA exhibited the growth of tumors throughout the buccal pouches, accompanied by notable changes in lipid peroxidation, antioxidant levels, and carcinogen-detoxifying agents. However, oral administration of BCA (20 mg/kg bw) every second day for fourteen weeks showed significant alteration in the histopathological changes and reduced incidence, volume, and burden of tumors in DMBA-exposed hamsters. BCA established substantial anti-lipid peroxidation effects and the ability to enhance antioxidant and carcinogen-detoxifying agent levels in DMBA-exposed animals. Conclusion: The outcomes of this investigation emphasize the chemopreventive and antioxidant capability of BCA against DMBA-induced oral carcinoma in hamsters.

Background: Compelling evidence implicates diabetes‐associated hyperglycemia as a promoter of tumor progression in oral potentially malignant disorders (OPMD). Yet, information on hyperglycemia‐induced cell signaling networks in oral oncology remains limited. Our group recently reported that glucose‐rich conditions significantly enhance oral dysplastic keratinocyte viability and migration through epidermal growth factor receptor (EGFR) activation, a pathway strongly linked to oral carcinogenesis. Here, we investigated the basal metabolic phenotype in these cells and whether specific glucose‐responsive EGFR ligands mediate these responses. Methods: Cell energy phenotype and lactate concentration were evaluated via commercially available assays. EGFR ligands in response to normal (5 mM) or high (20 mM) glucose were analyzed by quantitative real‐time PCR, ELISA, and western blotting. Cell viability and migration assays were performed in the presence of pharmacological inhibitors or RNA interference. Results: When compared to normal keratinocytes, basal glycolysis in oral dysplastic keratinocytes was significantly elevated. In highly glycolytic cells, high glucose‐activated EGFR increasing viability and migration. Notably, we identified amphiregulin (AREG) as the predominant glucose‐induced EGFR ligand. Indeed, enhanced cell migration in response to high glucose was blunted by EGFR inhibitor cetuximab and AREG siRNA. Conversely, AREG treatment under normal glucose conditions significantly increased cell viability, migration, lactate levels, and expression of glycolytic marker pyruvate kinase M2. Conclusion: These novel findings point to AREG as a potential high glucose‐induced EGFR activating ligand in highly glycolytic oral dysplastic keratinocytes. Future studies are warranted to gain more insight into the role of AREG in hyperglycemia‐associated OPMD tumor progression. [ABSTRACT FROM AUTHOR]

Frequent forms of malignancy localized to the oral cavity are considered a major health problem, especially in developing countries. Research on the experimental oral carcinogenesis inhibition using topical beta-carotene has led to the observation that beta-carotene significantly inhibits the formation of DMBA (7,12-dimethylbenz anthracene) and hamster squamous cell carcinomainduced oral pouch when used topically daily. In another study, 13-CIS-retinoic acid was used in the oral leukoplakia treatment where the efficacy of vitamin A in the oral leukoplakia treatment was highlighted. The efficacy of a mixture of ascorbic acid, glutathione, α-tocopherol, and β-carotene has shown that α-tocopherol and β-carotene can act synergistically to inhibit the growth of oral cancer. Analyzing the delay in oral cancer development using topical vitamin E demonstrated a significant delay in tumor formation compared to the animals from the control group. Extensive research has been conducted in experimental animals to indicate the anticancer activity of tocopherol, carotenoids, and retinoids on oral precancerous leukoplakia and oral cancer. The anticancer attributes of these micronutrients have been investigated in experiments on carcinogenesis inhibition, the prevention of oral cancer development, and oral carcinoma regression. Synergism has been shown in the anticancer activity of alpha-tocopherol and betacarotene. Synergism has been shown between anticancer alkylating agents such as cyclophosphamide, melphalan, and beta-carotene. In conclusion, antioxidant micronutrients such as beta-carotene are oral carcinogenesis inhibitors; vitamin E and beta-carotene can induce oral leukoplakia clinical regression, a premalignant lesion of oral cancer. [ABSTRACT FROM AUTHOR]

Probiotics modulate immune responses, enhance anti-tumoral immune surveillance, promote apoptosis of cancer cells, suppress tumor progression by their cytotoxic activity, and target the epigenetic changes in the cancer cell population. Evidence from the literature suggests that the role of probiotics in oral carcinogenesis is limited as compared to that in colon and gastric cancer. The present review aims to describe the immune modulation by probiotics in deterring carcinogenesis with an emphasis on oral cancer. We searched for relevant articles (in vitro and animal studies) published between January 2011 and December 2022 in PubMed, Scopus, and Google Scholar, both by electronic and manual means with the medical subject headings (MeSH) terms: “probiotics,” “carcinogenesis,” “immune modulation,” and “oral cancer.” The identified studies were analyzed by two independent reviewers according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Eight articles met the requirements and were included. The data suggested that probiotics had immunomodulatory and anti-tumorigenic effects. Clinical studies are required to encourage the assessment of probiotics to inhibit tumor cell proliferation, prevent metastasis, and support anti-cancer therapy.

Oral carcinogenesis is also dependent on the balance of the oral microbiota. Candida albicans is a member oral microbiota that acts as an opportunistic pathogen along with changes in the epithelium that can predispose to premalignancy and/or malignancy. This systematic review uses the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines to analyze the role of Candida albicans in the process of oral carcinogenesis. Eleven articles qualified inclusion criteria, matched keywords, and provided adequate information about the carcinogenesis parameters of Candida albicans in oral cancer. Candida albicans in oral carcinogenesis can be seen as significant virulent factors for patients with oral squamous cell carcinoma (OSCC) or potentially malignant disorder (OPMD) with normal adjacent mucosa. Candida albicans have a role in the process of oral carcinogenesis concerning morphological phenotype changes in cell structure and genotype and contribute to the formation of carcinogenic substances that can affect cell development towards malignancy.

Immune checkpoint molecule PD-1, expressed on the cell surface, impairs antigen-driven activation of T cells and thus plays a critical role in tumorigenesis, progression, and the poor prognosis of oral squamous cell carcinoma (OSCC). In addition, increasing evidence indicates that PD-1 carried on small extracellular vesicles (sEVs) also mediates tumor immunity, although their contributions to OSCC are yet unclear. Here, we investigated the biological functions of sEV PD-1 in patients with OSCC. The cell cycle, proliferation, apoptosis, migration, and invasion of CAL27 cell lines treated with or without sEV PD-1 were examined in vitro. We performed mass spectrometry to investigate the underlying biological process, combined with an immunohistochemical study of SCC7-bearing mice models and OSCC patient samples. In vitro data demonstrated that sEV PD-1 induced senescence and subsequent epithelial-mesenchymal transition (EMT) in CAL27 cells by ligating with tumor cell surface PD-L1 and activating the p38 mitogen-activated protein kinase (MAPK) pathway. Comprehensive immunohistochemical analysis of the xenograft mice models and OSCC patient samples revealed a very close correlation between the level of circulating sEV PD-1 and lymph node metastasis. These results demonstrate that circulating sEV PD-1 triggers senescence-initiated EMT in a PD-L1-p38 MAPK-dependent manner, contributing to tumor metastasis. It also suggests that the inhibition of sEV PD-1 may be a promising therapeutic target for the treatment of OSCC. [ABSTRACT FROM AUTHOR]

Introduction: Oral cancer is a serious health problem with an increasing incidence worldwide. Researchers have studied the potential anti-cancerous action of vitamin D and its association with several cancers including oral cancer. The purpose of this scoping review is to synthesize the existing literature on the role of vitamin D on oral cancer. Methods: A scoping review of the literature was conducted using the framework developed by Arkey and O'Malley and the PRISMA-ScR guidelines. Nine databases were searched for peer-reviewed human studies published in English that either investigated the association of vitamin D with, or its impact on either the prevention or treatment of oral cancer. The authors then extracted data using a predefined form to summarize information about article type, study design, participant characteristics, interventions, and outcomes. Results: Fifteen articles met the review criteria. Among the 15 studies, 11 were case–control, 3 were cohort studies, and 1 was a clinical trial. In four studies, the evidence supported a preventive action of vitamin D against oral cancer and a reduction in the negative side effects associated with chemo- and radiotherapy. Several studies that focused on genetic polymorphisms and the expression of the 1,25 dihydroxyvitamin D3 receptor (VDR) suggested significant associations with vitamin D and increased oral cancer risk and worse survival rates. In contrast, two studies did not reveal a strong association between vitamin D and oral cancer. Conclusions: The current evidence suggests an association between vitamin D deficiency and an increased risk of oral cancer. VDR gene polymorphisms might also be a part of future preventive and therapeutic strategies against oral cancer. Carefully designed studies are required to explore and define what role, if any, vitamin D might play in the prevention and treatment of oral cancer. [ABSTRACT FROM AUTHOR]

Model systems for oral cancer research have progressed from tumor epithelial cell cultures to in vivo systems that mimic oral cancer genetics, pathological characteristics, and tumor-stroma interactions of oral cancer patients. In the era of cancer immunotherapy, it is imperative to use model systems to test oral cancer prevention and therapeutic interventions in the presence of an immune system and to discover mechanisms of stromal contributions to oral cancer carcinogenesis. Here, we review in vivo mouse model systems commonly used for studying oral cancer and discuss the impact these models are having in advancing basic mechanisms, chemoprevention, and therapeutic intervention of oral cancer while highlighting recent discoveries concerning the role of immune cells in oral cancer. Improvements to in vivo model systems that highly recapitulate human oral cancer hold the key to identifying features of oral cancer initiation, progression, and invasion as well as molecular and cellular targets for prevention, therapeutic response, and immunotherapy development.

Background: Epithelial–mesenchymal transition is one of the main mechanisms for tumor progression and metastasis. Transcription factors such as TWIST1 are key regulators of the epithelial–mesenchymal transition and are regarded as potential therapeutic targets for the treatment of cancer. The purpose of this study was to examine TWIST1 as a possible epithelial‐mesenchymal transition‐related prognostic biomarker in oral epithelial dysplasia and oral tongue squamous cell carcinomas, as well as the biological behavior of TWIST1‐silencing in oral tongue squamous cell carcinomas cell lines. Methods: Immunohistochemical analysis of TWIST1, E‐cadherin, and N‐cadherin was carried out in 47 samples representing oral epithelial dysplasia and 41 oral tongue squamous cell carcinomas. The suppression of TWIST1 expression was performed using shRNA‐expression vectors in HSC‐3 and SCC‐9 cells to investigate in vitro the impact of TWIST1 on proliferation, apoptosis, viability, migration, and invasion of SCC‐9 and HSC‐3 cells. Results: The expression of nuclear TWIST1 was significantly higher in oral tongue squamous cell carcinomas than in oral epithelial dysplasis (p < 0.0001), whereas TWIST1 in the cytoplasm was more expressed in oral epithelial dysplasis (p = 0.012). The high cytoplasmic expression of TWIST1 was significantly associated with shortened overall survival (p < 0.05), and increased nuclear TWIST1 expression was significantly related to high risk of recurrence (p = 0.03). Knockdown of TWIST1 in oral tongue squamous cell carcinomas cells induced the expression of E‐cadherin and inhibited N‐cadherin, which were followed by decreased proliferation, migration, and invasion. Conclusions: Our research suggests that TWIST1 is linked to the development of oral tongue carcinogenesis and may be used as a prognostic indicator and therapeutic target for oral tongue squamous cell carcinomas patients. [ABSTRACT FROM AUTHOR]

Background: On the background of the epidemiological link between diabetes and oral cancer, the present study aimed to analyze the potential involvement of selected glucose transporters (GLUT1/GLUT3/GLUT4), if any, in such putative association. Methods and results: Oral carcinogenesis was induced by 4-nitroquinoline N-oxide in 10 non-diabetic and 10 diabetic rats; 8 non-diabetic and 7 diabetic rats served as controls. Expressions of selected GLUTs at mRNA and protein levels were analyzed in oral tissue (normal/lesion) by quantitative real-time PCR and immunohistochemistry respectively. Premalignant lesions (hyperplasia/dysplasia/carcinoma-in-situ) appeared on tongues of carcinogen-treated animals. Significant increase of GLUT1mRNA level was seen from normal to lesion tongues, along increasing lesion grades (from hyperplasia/mild dysplasia to moderate/severe dysplasia) and in lesions induced under hyperglycemic condition than that induced under normoglycemic one; a similar trend was found in transcript variant-1 of GLUT1, but not in variant-2. GLUT3 and GLUT4 mRNA levels were comparable among lesions irrespective of grades and glycemic status. Concordant to mRNA level, overall expression of GLUT1 protein was higher in tongue lesions in presence of hyperglycemia than in absence of such condition; non-lesion portions of tongues exposed to carcinogen showed a similar trend. Moreover in carcinogen-treated groups, non-lesion and lesion portions of tongues under hyperglycemic condition showed predominantly membranous expression for GLUT1 which was again significantly higher than equivalent portions of tongue under normoglycemic condition. Conclusion: Hyperglycemia seemed to favor GLUT1 over-expression and membrane localization of the protein during oral carcinogenesis. GLUT1 transcript variant-1 appeared to be more important than variant-2 in disease pathogenesis. [ABSTRACT FROM AUTHOR]

The objective of this study is to examine the chemopreventive effects of Nerolidol (NER) on hamster buccal pouch carcinogenesis (HBC) induced by 7,12‐dimethylbenz(a)anthracene (DMBA) in male golden Syrian hamsters. In this study, oral squamous cell carcinoma was developed in the buccal pouch of an oral painted hamster with 0.5% DMBA in liquid paraffin three times weekly for 12 weeks. To assess DMBA‐induced hamster buccal tissue carcinogenesis, biochemical endpoints such as Phase I and II detoxification enzymes, antioxidants, lipid peroxidation (LPO) by‐products, and renal function markers, as well as histopathological examinations, were used. Furthermore, the immunohistochemical studies of interleukin‐6 were investigated to find the inflammatory link in the HBC carcinogenesis. In our results, DMBA alone exposed hamsters showed 100% tumor growth, altered levels of antioxidants, detoxification agents, LPO, and renal function identifiers as compared to the control hamsters. The outcome in present biochemical, histopathological, and immunohistochemistry studies has been found a reverse in NER‐treated hamsters against the tumor. This study concluded that NER modulated the biochemical profiles (antioxidants, detoxification, LPO, and renal function markers) and inhibited tumor development in DMBA induced oral carcinogenesis. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to clarify the dynamic changes of exhaustion features in T cells during oral carcinogenesis. Materials and Methods: Mice were randomly divided into 4NQO group and control group. The exhaustion features of CD4+ and CD8+ T cells of both groups were detected by flow cytometry. Furthermore, multiplex immunohistochemistry was used to evaluate the expression of inhibitory receptors in human normal, dysplastic, and carcinogenesis tissues. Finally, anti‐PD‐1 antibody treatment was performed at the early premalignant phase of oral carcinogenesis. Results: The proportion of naive T cells in 4NQO group was lower than those in control group, while the proportion of effector memory T cells was higher in 4NQO group. The expression of inhibitory receptors on CD4+ and CD8+ T cells increased gradually during carcinogenesis. In contrast, the secretion of cytokines by CD4+ and CD8+ T cells decreased gradually with the progression stage. Strikingly, those changes occurred before the onset of oral carcinogenesis. The expression of inhibitory receptors on T cells increased gradually as the human tissues progressed from normal, dysplasia to carcinoma. Interestingly, PD‐1 blockade at the early premalignant phase could reverse carcinogenesis progression by restoring T cell function. Conclusions: T‐cell dysfunction was established at the early premalignant phase of oral carcinogenesis; PD‐1 blockade at the early premalignant phase can effectively reverse T‐cell exhaustion features and then prevent carcinogenesis progression. [ABSTRACT FROM AUTHOR]

The human body contains about 1014 bacteria which usually colonise different parts of the body. The bacterial flora is important for a person’s health as well as normal functioning of tissue and organ systems. Bacteria are single celled organisms and are found on almost all surfaces of human body. They act in synergy with host immune mechanism and provide protection against various undesirable foreign invasions, especially in the oral cavity, where they exist in a diversified form which survive in a symbiotic relationship with the host. When there is a disturbance in this equilibrium due to various factors like trauma or tobacco smoking, betel nut chewing and alcohol intake, which makes the mucous membrane more permeable to invading microorganisms, these commensal bacterial species can become virulent and give rise to oral diseases ranging from dental caries to oral carcinoma. The effects of these bacteria can be either direct or indirect initiation of chronic inflammation, formation of procarcinogens that contribute to the development of oral carcinoma. This article focuses on the role of oral bacterial flora in initiation and progression of oral carcinogenesis. Various bacterial and fungal species associated with oral carcinoma and predominant bacterial species in oral cavity and oropharyngeal region along with measures to prevent their adverse effects are described.

Human cancer development is a multistep process. A variety of endogenous and exogenous stimuli trigger a complex series of cellular and molecular changes that contribute to cancer formation, one of which is the creation of reactive oxygen species (ROS). Oral cancer is one of the most deadly health issues that humanity faces today. Oral cancer accounts for 2% to 3% of all cancers and is the 5th most frequent disease worldwide, according to the World Health Organization (WHO). Oxygen derived species such as hydrogen peroxide, superoxide anion radical, hydroxyl radical (OH• ), and singlet oxygen are well known to be cytotoxic and have been implicated in the etiology of a wide array of human diseases, including oral cancer. Various carcinogens may also partly exert their effect by generating reactive oxygen species (ROS) during their metabolism. Mutations can result from oxidative damage to cellular DNA, which could have a role in the onset and advancement of multistage carcinogenesis (including mouth cancer) via a variety of processes. ROS has an impact on central cellular processes such proliferation, apoptosis, and senescence, all of which have been linked to cancer development. Antioxidant deficiency or an oxidant-antioxidant imbalance can cause oxidative damage to cellular macromolecules, which can lead to cancer. Understanding the significance of reactive oxygen species (ROS) as essential mediators in signaling pathways may open up new avenues for pharmaceutical intervention. We review the current state of knowledge on the role of these oxidative modified cellular byproducts in serving as reliable biomarkers for oral cancer detection, prognosis and diagnosis. [ABSTRACT FROM AUTHOR]

The human body contains about 1014 bacteria which usually colonise different parts of the body. The bacterial flora is important for a person's health as well as normal functioning of tissue and organ systems. Bacteria are single celled organisms and are found on almost all surfaces of human body. They act in synergy with host immune mechanism and provide protection against various undesirable foreign invasions, especially in the oral cavity, where they exist in a diversified form which survive in a symbiotic relationship with the host. When there is a disturbance in this equilibrium due to various factors like trauma or tobacco smoking, betel nut chewing and alcohol intake, which makes the mucous membrane more permeable to invading microorganisms, these commensal bacterial species can become virulent and give rise to oral diseases ranging from dental caries to oral carcinoma. The effects of these bacteria can be either direct or indirect initiation of chronic inflammation, formation of procarcinogens that contribute to the development of oral carcinoma. This article focuses on the role of oral bacterial flora in initiation and progression of oral carcinogenesis. Various bacterial and fungal species associated with oral carcinoma and predominant bacterial species in oral cavity and oropharyngeal region along with measures to prevent their adverse effects are described. [ABSTRACT FROM AUTHOR]

Calcium is a strong inducer of keratinocyte differentiation. We have previously demonstrated that extracellular calcium promotes keratinocyte differentiation via E-cadherin-catenin complex-mediated phospholipase C-γ1 (PLC-γ1) activation in the plasma membrane. However, it is unclear whether dietary calcium regulates keratinocyte proliferation, differentiation or carcinogenesis. To address this issue, the rates of oral tumor and levels of proliferation and differentiation in the oral epithelium were assessed in mice on different calcium diets and the carcinogen 4-nitroquinoline-1-oxide. The results showed that mice on the high calcium diet had lower rates of oral tumors, lower levels of proliferation and higher levels of differentiation in the normal oral epithelium than those on the normal calcium diet. Higher levels of E-cadherin, β-catenin, p120-catenin (p120), epidermal growth factor receptor (EGFR), and calcium and lower levels of PLC-γ1 were also noted in the normal oral epithelium in mice on high calcium diet than the control mice. In contrast, mice on low calcium diet had opposite effects. However, dietary calcium had no effect on the proliferation, differentiation or the levels of E-cadherin, β-catenin, p120, PLC-γ1 and EGFR in oral tumors. These data indicate that dietary calcium increases calcium levels in oral epithelium, suppresses oral carcinogenesis, inhibits proliferation and promotes differentiation of normal oral epithelium. Increased E-cadherin, β-catenin, p120 and EGFR and decreased PLC-γ1 may participate in the inhibitory effect of dietary calcium in oral carcinogenesis.

This systematic review aims to highlight the molecular mechanisms by which whole cigarette smoke affects oral carcinogenesis and its progression in human oral cells, based on evidence from original research articles published in the literature. A literature search was conducted using three databases: Web of Science, Scopus, and PubMed from May to June 2024. The articles were screened, and the data were extracted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines (2020). The included studies were subsequently evaluated using the Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) tool for bias factors. From the 14 included studies, two types of cell lines were frequently utilized: human oral mucosal epithelial cells or oral squamous cell carcinoma cells. In these cell lines, one of three forms of exposure was applied: cigarette smoke, its extract, or condensate. The mechanism of oral carcinogenesis and tumor progression includes aberrations in the heme metabolic pathway, modulation of miRNA-145, NOD1 and BiP expression, MMP-2, MMP-9, and cathepsin modulation, abnormal TSPO binding, RIP2-mediated NF-κB activation, MZF1-mediated VEGF binding, and activation of the RAGE signaling pathway. In conclusion, cigarette smoke significantly influences the development and progression of oral squamous cell carcinoma, based on the evidence highlighted in human oral cells. While previous studies have focused on specific carcinogens and pathways, this review added to our understanding of the overall impact of whole cigarette smoke on oral carcinogenesis at the molecular and cellular levels., Competing Interests: Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: Universiti Sains Malaysia Research University Grant (1001/PPSG/8012345) provided funds for Cureus article processing charges/ Preferred Editing Service. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Li et al.)

Understanding the dynamics of the immune microenvironment is critical to the development of immuno-based strategies for the prevention of oral potentially malignant disorders transformation to oral squamous cell carcinoma (OSCC). We used laser capture microdissection and RNA-sequencing to profile the expression of 13 matched pairs of epithelial versus stromal compartments from normal mucosa, hyperplasia, dysplasia, and invasive tumors in the 4-nitroquinolein (4-NQO) murine model of oral carcinogenesis. Genes differentially expressed at each step of transformation were defined. Immune cell deconvolution and enrichment scores of various biological processes including immune-related ones were computed. Immunohistochemistry was also performed to characterize the immune infiltrates by T-cells (T-cells CD3+, helper CD4+, cytotoxic CD8+, regulatory FoxP3+), B-cells (B220+), and macrophages (M1 iNOS+, M2 CD163+) at each histological step. Enrichment of three independent M2 macrophages signatures were computed in 86 oral leukoplakia with available clinical outcome. Most gene expression changes were observed in the stromal compartment and related to immune biological processes. Immune cell deconvolution identified infiltration by the macrophage population as the most important quantitatively especially at the stage of dysplasia. In 86 patients with oral leukoplakia, three M2 macrophages signatures were independently associated with improved oral cancer-free survival. This study provides a better understanding of the dynamics of the immune microenvironment during oral carcinogenesis and highlights an unexpected association of M2 macrophages gene expression signatures with oral cancer free survival in patients with oral leukoplakia.

Oral cancer patients often have severe, chronic, and mechanically induced pain at the site of the primary cancer. Oral cancer pain is initiated and maintained in the cancer microenvironment and attributed to release of mediators that sensitize primary sensory nerves. This study was designed to investigate the histopathology associated with painful oral cancers in a preclinical model. The relationship of pain scores with pathologic variables was also investigated in a cohort of 72 oral cancer patients. Wild-type mice were exposed to the carcinogen, 4-nitroquinoline 1-oxide (4NQO). Nociceptive (pain) behavior was measured with the dolognawmeter, an operant device and assay for measuring functional and mechanical allodynia. Lesions developed on the tongues and esophagi of the 4NQO-treated animals and included hyperkeratoses, papillomas, dysplasias, and cancers. Papillomas included lesions with benign and dysplastic pathological features. Two histologic subtypes of squamous cell carcinomas (SCCs) were identified—SCCs with exophytic and invasive components associated with papillary lesions (pSCCs) and invasive SCCs without exophytic histology (iSCCs). Only the pSCC subtype of tongue cancer was associated with nociceptive behavior. Increased tumor size was associated with greater nociceptive behavior in the mouse model and more pain experienced by oral cancer patients. In addition, depth of invasion was associated with patient-reported pain. The pSCC histology identifies 4NQO-induced tongue cancers that are expected to be enriched for expression and release of nociceptive mediators. [ABSTRACT FROM AUTHOR]

Background. Oral cancer progresses from hyperplastic epithelial lesions through dysplasia to invasive carcinoma. The critical needs in oral cancer treatment are expanding our knowledge of malignant tumour progression and the development of useful approaches to prevent dysplastic lesions. This study was designed to gain insights into the underlying metabolic transformations that occur during the process of oral carcinogenesis. Methods. We used gas chromatography-mass spectrometry (GC-MS) in conjunction with multivariate statistical techniques to observe alterations in serum metabolites in a 4-Nitroquinoline 1-oxide (4NQO)-induced rat tongue carcinogenesis model. Thirty-eight male rats were randomly divided into two groups, including the 4NQOinduced model group of 30 rats and the healthy control group of five rats. Animals were sacrificed at weeks 9, 13, 20, 24, and 32, post-4NQO treatment. Tissue samples were collected for histopathological examinations and blood samples were collected for metabolomic analysis. Partial least squares discriminate analysis (PLS-DA) models generated from GC-MS metabolic profile data showed robust discrimination from rats with oral premalignant and malignant lesions induced by 4NQO, and normal controls. Results. The results found 16 metabolites associated with 4NQO-induced rat tongue carcinogenesis. Dysregulated arachidonic acid, fatty acid, and glycine metabolism, as well as disturbed tricarboxylic acid (TCA) cycle and mitochondrial respiratory chains were observed in the animal model. The PLS-DA models of metabolomic results demonstrated good separations between the 4NQO-induced model group and the normal control group. Conclusion. We found several metabolites modulated by 4NQO and provide a good reference for further study of early diagnosis in oral cancer. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of the immune microenvironment is critical to the development of immuno-based strategies for the prevention of oral potentially malignant disorders transformation to oral squamous cell carcinoma (OSCC). We used laser capture microdissection and RNA-sequencing to profile the expression of 13 matched pairs of epithelial versus stromal compartments from normal mucosa, hyperplasia, dysplasia, and invasive tumors in the 4-nitroquinolein (4-NQO) murine model of oral carcinogenesis. Genes differentially expressed at each step of transformation were defined. Immune cell deconvolution and enrichment scores of various biological processes including immune-related ones were computed. Immunohistochemistry was also performed to characterize the immune infiltrates by T-cells (T-cells CD3+, helper CD4+, cytotoxic CD8+, regulatory FoxP3+), B-cells (B220+), and macrophages (M1 iNOS+, M2 CD163+) at each histological step. Enrichment of three independent M2 macrophages signatures were computed in 86 oral leukoplakia with available clinical outcome. Most gene expression changes were observed in the stromal compartment and related to immune biological processes. Immune cell deconvolution identified infiltration by the macrophage population as the most important quantitatively especially at the stage of dysplasia. In 86 patients with oral leukoplakia, three M2 macrophages signatures were independently associated with improved oral cancer-free survival. This study provides a better understanding of the dynamics of the immune microenvironment during oral carcinogenesis and highlights an unexpected association of M2 macrophages gene expression signatures with oral cancer free survival in patients with oral leukoplakia. [ABSTRACT FROM AUTHOR]

This study aimed to explore new therapeutic targets to improve the survival rate of patients with oral squamous cell carcinoma (OSCC).MiR‐210‐3p, EphrinA3 and EMT related indices were evaluated in OSCC tissues and cell lines. In addition, the relationship between differential EphrinA3 expression and tumour progression was explored through molecular biology techniques, in vitro functional experiments and tumour xenotransplantation models. The expression of EphrinA3 (rs = −0.719, P <.05) and E‐cadherin (rs = −0.856, P <.05) was negatively correlated with the pathological grading in OSCC tissues. Protein clustering shows EphrinA3 may be associated with tumour progression. EphrinA3 also can regulate the biological behaviour of oral cancer cells. And it regulates the EMT by the PI3K/AKT signalling pathway. MiR‐210‐3p targeted the gen EFNA3. Up‐regulation of miR‐210‐3p expression can decrease the expression of EphrinA3 and further to influence the biological behaviour of OSCC. The miR‐210‐3p‐EphrinA3‐PI3K/AKT signalling axis plays an important role in the progress of OSCC. EphrinA3 may serve as a novel target for oral cancer treatment. [ABSTRACT FROM AUTHOR]

Human salivary aldehyde dehydrogenase (hsALDH) protects us from the toxic effect of aldehydes. It has both diagnostic and therapeutic importance. Citral possesses many biological and pharmacological properties. The aim of this work was to investigate the inhibitory effect and the mechanism of inhibition of citral on hsALDH. Citral inhibits the dehydrogenase activity of hsALDH. It decreased the substrate affinity and to a lesser extent, the catalytic efficiency of hsALDH. Citral showed linear mixed-type inhibition with a higher tendency of competitive behavior with little, but significant, non-competitive inhibition. The nucleophilicity of active site Cys residue is not a significant contributing factor in the inhibition process. Citral shows uncompetitive inhibition towards the co-enzyme (NAD+). α-helix and β-sheet content of the enzyme were changed in presence of citral. Biophysical studies showed that citral quenches the intrinsic fluorescence of hsALDH in a static manner by forming complex with the enzyme. Molecular docking study showed that both the isomers of citral bind to the catalytic site of hsALDH interacting with few evolutionary preserved amino acid residues through multiple non-covalent interactions. Ligand efficiency metrics values indicate that citral is an efficient ligand for the enzyme in terms of its physicochemical and pharmacokinetic properties. [ABSTRACT FROM AUTHOR]

Langerhans cells (LCs) are antigen presenting cells. This study assessed the LC counts in oral epithelial dysplasia (OED) and their correlation to clinicopathological parameters. Methods: This study examined the LC counts in the epithelia and subepithelial connective tissues of 58 patients with OED (21 mild, 18 moderate, and 19 severe OED lesions) and 10 specimens of normal oral mucosa (NOM) by anti-S-100 protein immunostaining. Results: We found that the mean LC counts in the epithelia or subepithelial connective tissues increased significantly from NOM samples through mild and moderate OED to severe OED samples. In addition, a significant correlation was found between higher mean LC counts in the dysplastic epithelia of OED samples and OED lesions with thicker epithelial layers (p

Oral squamous cell carcinoma is the predominant subtype of head and neck squamous cell carcinoma, characterized by a challenging prognosis. In this study, we established a murine model of oral carcinogenesis using 4-nitroquinoline-1-oxide (4-NQO) induction to investigate the impact of immunotherapy on microenvironmental alterations. Mice in the precancerous condition were randomly divided into two groups: one receiving programmed death-1 (PD1) monoclonal antibody treatment and the other, control immunoglobulin G. Our observations showed that while PD1 blockade effectively delayed the progression of carcinogenesis, it did not completely impede or reverse it. To unravel the underlying reasons for the limited effectiveness of PD1 blockade, we collected tongue lesions and applied mass cytometry (CyTOF) and RNA sequencing (RNA-seq) to characterize the microenvironment. CyTOF analysis revealed an increased macrophage subset (expressing high levels of IFNγ and iNOS) alongside a diminished Th1-like subset (exhibiting low expression of TCF7) and three myeloid-derived suppressor cell subsets (displaying low expression of MHC Class II or IFNγ) following anti-PD1 treatment. Notably, we observed an increased presence of cancer-associated fibroblasts (CAFs) expressing collagen-related genes after PD1 blockade. Furthermore, we found a negative correlation between the infiltration levels of CAFs and CD8 + T cells. These findings were validated in murine tongue tissue slides, and publicly available multi-omics datasets. Our results suggest that CAFs may impair the therapeutic efficacy of PD1 blockade in oral carcinogenesis by the remodeling of the extracellular matrix., (© 2023 Wiley Periodicals LLC.)

Dysbiosis in the oral environment may play a role in the etiopathogenesis of oral squamous cell carcinoma (OSCC). This review aims to summarize the current knowledge about the association of oral microbiota with OSCC and to describe possible etiopathogenetic mechanisms involved in processes of OSCC development and progression. Association studies included in this review were designed as case–control/case studies, analyzing the bacteriome, mycobiome, and virome from saliva, oral rinses, oral mucosal swabs, or oral mucosal tissue samples (deep and superficial) and comparing the results in healthy individuals to those with OSCC and/or with premalignant lesions. Changes in relative abundances of specific bacteria (e.g., Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus sp.) and fungi (especially Candida sp.) were associated with OSCC. Viruses can also play a role; while the results of studies investigating the role of human papillomavirus in OSCC development are controversial, Epstein–Barr virus was positively correlated with OSCC. The oral microbiota has been linked to tumorigenesis through a variety of mechanisms, including the stimulation of cell proliferation, tumor invasiveness, angiogenesis, inhibition of cell apoptosis, induction of chronic inflammation, or production of oncometabolites. We also advocate for the necessity of performing a complex analysis of the microbiome in further studies and of standardizing the sampling procedures by establishing guidelines to support future meta-analyses.

How have revolutionary cell proliferation theories progressed over the past 30 years? [ABSTRACT FROM AUTHOR]

T cells and dendritic cells (DCs) that are positive for the tissue-resident marker CD103 play a vital role in antitumor immunity. In this study, multiplexed immunohistochemistry was applied to stain CD103 and the T-cell marker CD8 as well as the DC marker CD11c on formalin-fixed, paraffin-embedded oral squamous cell carcinoma (OSCC) tissues. Then, the density of CD103+CD8+ and CD103+CD11c+ tumor-infiltrating lymphocytes (TILs) in the intratumoral and stromal regions was calculated, and the correlation of CD103+CD8+ TIL and CD103+CD11c+ TIL density with OSCC patient prognosis was analyzed. The results revealed that CD103+CD8+ TILs and CD103+CD11c+ TILs were abundant in the stromal region and that increased stromal CD103+CD8+ TIL and intratumoral CD103+CD11c+ TIL density indicated a favorable prognosis. Moreover, we freshly isolated TILs from OSCC samples and performed flow cytometry to verify that CD103+CD8+ TILs display a tissue-resident memory T-cell (Trm) phenotype, and we discriminated CD103+CD11c+ TILs from tumor-associated macrophages. [ABSTRACT FROM AUTHOR]

Traditional tobacco products have well-known systemic and local oral effects, including inflammation, vasoconstriction, delayed wound healing, and increased severity of periodontal disease. Specifically in the oral cavity and the lung, cigarette smoking produces cancer, increased infectivity, acute and chronic inflammation, changes in gene expression in epithelial lining cells, and microbiome changes. In recent years, cigarette smoking has greatly decreased in the United States, but the use of new tobacco products has gained tremendous popularity. Without significant knowledge of the oral sequelae of products such as electronic cigarettes, researchers must evaluate current in vitro and in vivo methods to study these agents, as well as develop new tools to adequately study their effects. Some in vitro testing has been performed for electronic cigarettes, including toxicologic models and assays, but these mostly study the effect on the respiratory tract. Recently, direct exposure of the aerosol to in vitro 3-dimensional tissue constructs has been performed, demonstrating changes in cell viability and inflammatory cytokines. For in vivo studies, a universal e-cigarette testing machine or standard vaping regime is needed. A standard research electronic cigarette has recently been developed by the National Institute of Drug Abuse, and other devices delivering aerosols with different nicotine concentrations are becoming available. One of the biggest challenges in this research is keeping up with the new products and the rapidly changing technologies in the industry. [ABSTRACT FROM AUTHOR]

The oral microbiome is composed of microorganisms residing in the oral cavity, which are critical components of health and disease. Disruption of the oral microbiome has been proven to influence the course of oral diseases, especially among immunocompromised patients. Oral microbiome is comprised of inter-kingdom microorganisms, including yeasts such as Candida albicans, bacteria, archaea and viruses. These microorganisms can interact synergistically, mutualistically and antagonistically, wherein the sum of these interactions dictates the composition of the oral microbiome. For instance, polymicrobial interactions can improve the ability of C albicans to form biofilm, which subsequently increases the colonisation of oral mucosa by the yeast. Polymicrobial interactions of C albicans with other members of the oral microbiome have been reported to enhance the malignant phenotype of oral cancer cells, such as the attachment to extracellular matrix molecules (ECM) and epithelial-mesenchymal transition (EMT). Polymicrobial interactions may also exacerbate an inflammatory response in oral epithelial cells, which may play a role in carcinogenesis. This review focuses on the role of polymicrobial interactions between C albicans and other oral microorganisms, including its role in promoting oral carcinogenesis. [ABSTRACT FROM AUTHOR]

Signal transducer and activator of transcription (STAT)-3 lies at the convergence point of key pathways involved in many malignancies including oral squamous cell carcinoma (OSCC). Endoplasmic reticulum stress (ERS) and the unfolded protein response have been shown to be involved in the pathogenesis and progression of different cancers by influencing key cellular processes such as apoptosis. We investigated the differential expression of STAT3 pathway-related genes and proteins under ERS in OSCC. Three normal oral keratinocyte (NOK) and three OSCC cell lines were subjected to tunicamycin to induce ERS for 24 h or to the vehicle medium as control. A pathway-focussed array was used to analyse the modulation of STAT3 pathway gene expression under ERS using qPCR. The expression of key regulated proteins was investigated in the cell lines using immunocytochemistry and in 76 OSCC and 9 normal oral mucosa (NOM) tissue samples using tissue microarray technology and immunohistochemistry. ERS resulted in up-regulation of interleukin-6 receptor (IL6R) gene in NOK cell lines (p = 0.001) and IL5 (p = 0.005) and IL22 (p = 0.024) in OSCC cell lines. Greater STAT3 (p = 0.019) and leukaemia inhibitory factor receptor (p = 0.042) protein expression was observed in treated than untreated NOK cell lines. The gene and protein regulation patterns show that ERS plays a role in modifying the tumour microenvironment in OSCC by up-regulating tumour-promoting cytokines. [ABSTRACT FROM AUTHOR]

Highlights • Cyclin D1 overexpression was found in 28.7% of the cases of OSCC. • Cyclin D1 overexpression is associated with poor clinicopathological factors classically associated with a poor prognosis. • Measurement of cyclin D1 expression may be useful to predict the prognosis of patients with OSCC. Abstract Objective To evaluate the association of cyclin D1 overexpression with clinicopathological parameters classically considered of prognostic value in OSCC (T, N, M, clinical stage, degree of differentiation, invasive morphology and, cellular proliferation index). Design A retrospective immunohistochemical study was conducted of cyclin D1 and ki-67 expression in 68 OSCCs from 54 patients. Cases were scanned using a digital pathology system. The tumor expression of markers was assessed in four randomly selected fields (40x), and a semi-automatized count was conducted of cyclin D1-positive and -negative cells. Results Cyclin D1 overexpression was found in 28.7% of the cases of OSCC. It was significantly and positively associated with the following clinicopathological parameters: low tumor differentiation degree (p = 0.030), invasive morphology (p = 0.045), and proliferative phenotype according to tumor cell ki-67 expression (p = 0.018). Conclusions Cyclin D1 overexpression is an event of oral carcinogenesis associated with clinicopathological parameters classically associated with a poor prognosis in patients with OSCC. [ABSTRACT FROM AUTHOR]