Clinical relevance of the tumor microenvironment and immune escape of oral squamous cell carcinoma

Enhanced lipid biosynthesis in oral squamous cell carcinoma cancer-associated fibroblasts contributes to tumor progression: Role of IL8/AKT/p-ACLY axis

Lipid metabolic reprogramming of tumor cells has been proven to play a critical role in tumor initiation and development. However, lipid metabolism in cancer-associated fibroblasts (CAFs) has rarely been studied, particularly in CAFs of oral squamous cell carcinoma (OSCC). Additionally, the molecular mechanism by which tumor cells regulate lipid metabolism in fibroblasts is unclear. In this study, we found that phosphorylated ATP citrate lyase (p-ACLY), a key lipid metabolic enzyme, was upregulated in OSCC CAFs. Compared to paracancerous normal fibroblasts, CAFs showed enhanced lipid synthesis, such as elevated cytosolic acetyl-CoA level and accumulation of lipid droplets. Conversely, reduction of p-ACLY level blocked this biological process. In addition, blocking lipid synthesis in CAFs or inhibiting fatty acid uptake by OSCC cells reduced the promotive effects of CAFs on OSCC cell proliferation, invasion, and migration. These findings suggested that CAFs are one of lipid sources required for OSCC progression. Mechanistically, AKT signaling activation was involved in the upregulation of p-ACLY level and lipid synthesis in CAFs. Interleukin-8 (IL8), an exocrine cytokine of OSCC cells, could activate AKT and then phosphorylate ACLY in fibroblasts. This study suggested that the IL8/AKT/p-ACLY axis could be considered as a potential target for OSCC treatment.

The Role of Infiltrated T Lymphocyte in Oral Squamous Cell Carcinoma: Insights into Clinicopathological Characteristics and Prognosis

Background

To compare and analyze the presence of CD4+ and CD8 + lymphocyte infiltrates in Oral squamous cell carcinoma (OSCC) tissue versus adjacent tissue and their clinical significance.

Methods

We enrolled a total of 152 patients diagnosed with OSCC, all of whom had confirmed diagnoses through pathological reports. Clinical and demographics data were extracted from medical records. Tissue microarrays were constructed and immunohistochemical staining for CD4 and CD8 was performed.

Findings

The average number of infiltrating CD4+ T cells in OSCC tumor tissue was 1026.22±1163.36 cells/mm2, which did not significantly differ from the count in adjacent tissue, which was 1163.36±1013.23 cells/mm2. However, the number of CD8+ T cell infiltration in tumor tissue was significantly higher than in adjacent tissue (655.25±705.70 vs 504.56±659.26 cells/mm2, p = 0.026). We observed that, among patients who consumed alcohol, the CD4+ T cell infiltration in tumor tissue being significantly lower than that in adjacent tissue (P=0.036). Moreover, the CD8+ T cell infiltration in cancer tissue was significantly higher than in adjacent tissue for T1-2 patients (p=0.005). Patients with higher CD8+ T cell in tumor tissue exhibited significantly improved overall survival (p = 0.043). Multivariate analyses revealed that alcohol consumption had a significant impact on the number of CD4+T lymphocytes in tumor tissue (OR = 0.403, P = 0.033) while T stage was the independent factor affecting CD8+ T lymphocyte infiltration in tumor tissue (OR = 0.459, P = 0.031).

Interpretation

OSCC patients with a higher number of CD8+ T lymphocyte infiltration in tumor tissue exhibited an improved prognosis.

A study on the survival prediction for patients with oral cancer in southwest China

OBJECTIVE

The prognostic value of the variables were evaluated in 418 postoperative oral cancer patients with oral cancer in southwest China between January 2013 and December 2020. Nomogram was developed based on the study, and its predictive performance and clinical utility were evaluated.

RESULTS

The univariate analysis showed gender, preoperative fibrinogen, preoperative platelet-to-lymphocyte ratio (PLR), and preoperative neutrophil-to-lymphocyte ratio, flap repair of defect, functional neck dissection (FND), tumor differentiation, tumor, node, metastasis stage, lymph node metastasis, the maximum tumor diameter, and postoperative radiotherapy had a significant influence on the survival of patients with oral cancer in southwest China (p < 0.05).The multivariate analysis showed preoperative PLR value, FND, and tumor differentiation had significant influence on the prediction of survival (p < 0.05). However, smoking and drinking are not prognostic risk factors for oral cancer. The discriminant analysis showed 66.3% of the patients could be correctly predicted for postoperative survival, while both the C-index and decision curve analysis (DCA) showed this study may be taken as a reference for predicting the postoperative survival of patients with oral cancer.

CONCLUSION

Preoperative PLR, FND, and tumor differentiation are independent prognostic factors for patients with oral cancer in southwest China. The results of this study have been visualized using a nomogram and a DCA.

Bioinformatic analysis and experimental validation of cuproptosis-related LncRNA as a novel biomarker for prognosis and immunotherapy of oral squamous cell carcinoma

BACKGROUND

The novel form of regulatory cell death, cuproptosis, is characterized by proteotoxicity, which ultimately leads to cell death. Its targeting has emerged as a promising therapeutic approach for oral squamous cell carcinoma (OSCC). Long noncoding RNAs (lncRNAs) participate in epigenetic regulation and have been linked to the progression, prognosis, and treatment of OSCC. Thus, this study aimed to identify new cuproptosis-related lncRNAs (CRLs), establish predictive models for clinical prognosis, immune response, and drug sensitivity, and provide novel insights into immune escape and tumor drug resistance.

METHODS

The present study screened eight CRLs (THAP9-AS1, STARD4-AS1, WDFY3-AS2, LINC00847, CDKN2A-DT, AL132800.1, GCC2-AS1, AC005746.1) using Lasso Cox regression analysis to develop an eight-CRL prognostic model. Patients were categorized into high- and low-risk groups using risk scores. To evaluate the predictive ability of the model, Kaplan-Meier analysis, ROC curves, and nomograms were employed. Furthermore, the study investigated the differences in immune function and anticancer drug sensitivity between the high- and low-risk groups. To validate the expression of CRLs in the model, OSCC cell lines were subjected to quantitative real-time fluorescence PCR (qRT-PCR).

RESULTS

The results of the study showed that the high-risk group had a shorter overall survival (OS) time in OSCC patients. Cox regression analysis demonstrated that the high-risk score was an independent risk factor for a poor prognosis. The validity of the model was confirmed using ROC curve analysis, and a nomogram was developed to predict the prognosis of OSCC patients. Furthermore, patients in the high-risk group with high TMB had a poorer prognosis. Patients in the low-risk group responded better to immunotherapy than those in the high-risk group. Additionally, the risk scores were significantly associated with drug sensitivity in OSCC patients. Finally, the findings of qRT-PCR supported the reliability of the proposed risk model.

CONCLUSION

The study identified and established the 8-CRL model, which represents a novel pathway of lncRNA regulation of cuproptosis in OSCC. This model provides guidance for the prognosis and treatment of OSCC and offers a new insight into immune escape and tumor drug resistance.

Oral tumor heterogeneity, its implications for patient monitoring and designing anti-cancer strategies

Oral cancer tumors occur in the mouth and are mainly derived from oral mucosa linings. It is one of the most common and fatal malignant diseases worldwide. The intratumor heterogeneity (ITH) of oral cancerous tumor is vast, so it is challenging to study and interpret. Due to environmental selection pressures, ITH arises through diverse genetic, epigenetic, and metabolic alterations. The ITH also talks about peri-tumoral vascular/ lymphatic growth, perineural permeation, tumor necrosis, invasion, and clonal expansion/ the coexistence of multiple subclones in a single tumor. The heterogeneity offers tumors the adaptability to survive, induce growth/ metastasis, and, most importantly, escape antitumor therapy. Unfortunately, the ITH is prioritized less in determining disease pathology than the traditional TNM classifications or tumor grade. Understanding ITH is challenging, but with the advancement of technology, this ITH can be decoded. Tumor genomics, proteomics, metabolomics, and other modern analyses can provide vast information. This information in clinics can assist in understanding a tumor's severity and be used for diagnostic, prognostic, and therapeutic decision-making. Lastly, the oral tumor ITH can lead to individualized, targeted therapy strategies fighting against OC.

Spatial subsetting enables integrative modeling of oral squamous cell carcinoma multiplex imaging data

Oral squamous cell carcinoma (OSCC), a prevalent and aggressive neoplasm, poses a significant challenge due to poor prognosis and limited prognostic biomarkers. Leveraging highly multiplexed imaging mass cytometry, we investigated the tumor immune microenvironment (TIME) in OSCC biopsies, characterizing immune cell distribution and signaling activity at the tumor-invasive front. Our spatial subsetting approach standardized cellular populations by tissue zone, improving feature reproducibility and revealing TIME patterns accompanying loss-of-differentiation. Employing a machine-learning pipeline combining reliable feature selection with multivariable modeling, we achieved accurate histological grade classification (AUC = 0.88). Three model features correlated with clinical outcomes in an independent cohort: granulocyte MAPKAPK2 signaling at the tumor front, stromal CD4+ memory T cell size, and the distance of fibroblasts from the tumor border. This study establishes a robust modeling framework for distilling complex imaging data, uncovering sentinel characteristics of the OSCC TIME to facilitate prognostic biomarkers discovery for recurrence risk stratification and immunomodulatory therapy development.

The Complex Role of the Microbiome in Non-Small Cell Lung Cancer Development and Progression

In recent years, there has been a growing interest in the relationship between microorganisms in the surrounding environment and cancer cells. While the tumor microenvironment predominantly comprises cancer cells, stromal cells, and immune cells, emerging research highlights the significant contributions of microbial cells to tumor development and progression. Although the impact of the gut microbiome on treatment response in lung cancer is well established, recent investigations indicate complex roles of lung microbiota in lung cancer. This article focuses on recent findings on the human lung microbiome and its impacts in cancer development and progression. We delve into the characteristics of the lung microbiome and its influence on lung cancer development. Additionally, we explore the characteristics of the intratumoral microbiome, the metabolic interactions between lung tumor cells, and how microorganism-produced metabolites can contribute to cancer progression. Furthermore, we provide a comprehensive review of the current literature on the lung microbiome and its implications for the metastatic potential of tumor cells. Additionally, this review discusses the potential for therapeutic modulation of the microbiome to establish lung cancer prevention strategies and optimize lung cancer treatment.

Oral squamous cell carcinomas: state of the field and emerging directions

Oral squamous cell carcinoma (OSCC) develops on the mucosal epithelium of the oral cavity. It accounts for approximately 90% of oral malignancies and impairs appearance, pronunciation, swallowing, and flavor perception. In 2020, 377,713 OSCC cases were reported globally. According to the Global Cancer Observatory (GCO), the incidence of OSCC will rise by approximately 40% by 2040, accompanied by a growth in mortality. Persistent exposure to various risk factors, including tobacco, alcohol, betel quid (BQ), and human papillomavirus (HPV), will lead to the development of oral potentially malignant disorders (OPMDs), which are oral mucosal lesions with an increased risk of developing into OSCC. Complex and multifactorial, the oncogenesis process involves genetic alteration, epigenetic modification, and a dysregulated tumor microenvironment. Although various therapeutic interventions, such as chemotherapy, radiation, immunotherapy, and nanomedicine, have been proposed to prevent or treat OSCC and OPMDs, understanding the mechanism of malignancies will facilitate the identification of therapeutic and prognostic factors, thereby improving the efficacy of treatment for OSCC patients. This review summarizes the mechanisms involved in OSCC. Moreover, the current therapeutic interventions and prognostic methods for OSCC and OPMDs are discussed to facilitate comprehension and provide several prospective outlooks for the fields.

The expression of nicotinic acetylcholine receptor subunits and their associations with local immune cells and prognosis in oral squamous cell carcinoma

BACKGROUND

Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels that may be responsible for cancer cell proliferation, epithelial-mesenchymal transition (EMT), and immune regulation. However, little is known about the associations of different nAChR subunits with tumor microenvironment in oral squamous cell carcinoma (OSCC).

METHODS

We retrospectively reviewed pathology samples from 75 OSCC patients by immunohistochemistry. In addition, a cohort of 307 OSCC patients in The Cancer Genome Atlas was analyzed.

RESULTS

Subunit α1 was specific to peri-OSCC skeletal muscle. Increased α1 was associated with increased CD44 (cancer stem cells), increased CD3 and 8 (T cells), increased CD56 and 16 (natural killer cells), a decreased T stage, and an increased N stage. Increased α3 was associated with increased CD56 and 16. Increased α5 was associated with decreased CD3, 8, and 56, a decreased T stage, an increased N stage, worse survival, and decreased epithelial features. Increased α7 was associated with increased CD3, 8, 56, and 16, decreased tumor/peritumor ratios of CD3, 8, and 56 immune cells, and increased epithelial features. Increased local immune cells were associated with a better prognosis.

CONCLUSIONS

α5 is the only subunit associated with decreased local immune cells and worse survival, while α1, α3, and α7 are associated with increased local immune cells in OSCC. α5 and α7 are correlated with different EMT states to be mesenchymal-like and epithelial-like OSCC, respectively. Protein expression data of the nAChR subunits, complementary to gene expression data, could provide meaningful information regarding the EMT status of OSCC associated with immune responses and prognosis.

Comprehensive bioinformatics analysis combined with experimental validation to screen biomarkers for malignant transformation of oral leukoplakia

Oral leukoplakia (OLK) is the most common potentially malignant disorders in the oral cavity. This study aimed to screen the key genes of OLK malignant transformation using the Gene Expression Omnibus (GEO) database and experiments. In this study, the GEO database was employed to screen OLK malignant transformation-related genes, which were subsequently identified with a series of bioinformatic analyses. External validation showed that the model based on LAPTM4B, NR3C1, and COX6A1 had high accuracy in diagnosing OLK malignant transformation. Furthermore, the DMBA-induced potentially malignant disorders and OSCC models in vivo and real-time PCR experiment in vitro further verified the database analysis results. In conclusion, three key genes (LAPTM4B, NR3C1, and COX6A1) were screened as potential biomarkers for the diagnosis and treatment of OLK malignant transformation.

Metabolic programming and immune suppression in the tumor microenvironment

Increased glucose metabolism and uptake are characteristic of many tumors and used clinically to diagnose and monitor cancer progression. In addition to cancer cells, the tumor microenvironment (TME) encompasses a wide range of stromal, innate, and adaptive immune cells. Cooperation and competition between these cell populations supports tumor proliferation, progression, metastasis, and immune evasion. Cellular heterogeneity leads to metabolic heterogeneity because metabolic programs within the tumor are dependent not only on the TME cellular composition but also on cell states, location, and nutrient availability. In addition to driving metabolic plasticity of cancer cells, altered nutrients and signals in the TME can lead to metabolic immune suppression of effector cells and promote regulatory immune cells. Here we discuss how metabolic programming of cells within the TME promotes tumor proliferation, progression, and metastasis. We also discuss how targeting metabolic heterogeneity may offer therapeutic opportunities to overcome immune suppression and augment immunotherapies.

IRF4 as a novel target involved in malignant transformation of oral submucous fibrosis into oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) in the context of oral submucous fibrosis (OSF) has a high incidence owing to undefined pathogenesis. Identifying key genes and exploring the underlying molecular mechanisms involved in the conversion of OSF into OSCC are in urgent need. Differentially expressed genes (DEGs) between OSCC and OSF were dug from GEO databases and a total of 170 DEGs were acquired. Functional association of DEGs were analyzed by GO and KEGG. Protein-protein interactions (PPIs) analysis was carried out and candidate biomarkers were identified by Gene co-expression analysis and Cox analyses. Hub genes were confirmed by qRT-PCR in tissues and cell lines, of which we found that IRF4 mRNA was successively up-regulated from Normal to OSF and then to OSCC and associated with immune infiltrating levels. In addition, Immunohistochemical (IHC) and Immunofluorescence (IF) assays were conducted to validate the consistent upregulation of IRF4 and the oncogene role of IRF4 in OSF and OSCC at translation level. IRF4 may be indicative biomarker in transformation of OSF into OSCC. High IRF4 expression contribute to increased immune infiltration of OSCC and may provide a novel diagnostic marker for OSCC patients translated from OSF.

Oncostatin M receptor is overexpressed in oral squamous cell carcinoma and connected to poor prognosis

BACKGROUND

Oncostatin M receptor is an interleukin 6 receptor with great influence on inflammation and cancer progression. However, the function of oncostatin M receptor in oral squamous cell carcinoma remains unknown.

METHODS

Oncostatin M receptor expression was explored with TIMER and TCGA databases. The mRNA and protein expressions of oncostatin M receptor were detected in oral tissues. The association between oncostatin M receptor expression and clinicopathological characteristics was analyzed, and the prognostic value of oncostatin M receptor was determined. Immune statues of oncostatin M receptor were analyzed by TIMER and TISIDB. The underlying mechanisms of oncostatin M receptor in oral squamous cell carcinoma was also explored preliminarily.

RESULTS

Oncostatin M receptor was dysregulated in many cancers. Both mRNA and protein levels of oncostatin M receptor in oral squamous cell carcinoma tissues were significantly higher than that in normal oral tissues. Oncostatin M receptor expression was connected to differentiation, lymph node metastasis, tumor node metastasis (TNM) stage, perineural invasion and vascular invasion. Oncostatin M receptor expression was an independent prognostic factor associated with overall survivals. Oncostatin M receptor expression was significantly related to CD8⁺ T cell and interleukin 6 receptor. High oncostatin M receptor expression was associated with focal adhesion, extracellular matrix (ECM) receptor interaction, and JAK/STAT signaling pathway.

CONCLUSION

Oncostatin M receptor was overexpressed in oral squamous cell carcinoma and related to overall survival. Oncostatin M receptor expression has potential to become an effective prognostic biomarker for oral squamous cell carcinoma patients.

The exploration of new biomarkers for oral cancer through the ceRNA network and immune microenvironment analysis

The competitive endogenous RNA (ceRNA) and tumor-penetrating immune cells may be related to the prognosis of oral cancer. However, few studies have focused on the correlation between ceRNAs and immune cells. Thus, we developed a method based on a ceRNA network and tumor-infiltrating immune cells to elucidate the molecular pathways that may predict prognosis in patients with oral cancer. Download RNAseq expression data of oral cancer and control samples from the Cancer Genome Atlas (TCGA), obtain differentially expressed genes and establish a ceRNA network. The cox analysis and lasso regression analysis were used to screen key RNAs to establish a prognostic risk assessment model, and draw a 1.3.5-year forecast nomogram. Then the CIBERSORT algorithm was used to screen important tumor immune infiltrating cells associated with oral cancer. Another prognostic predictive model related to immune cells was established. Finally, co-expression analysis was applied to explore the relationship between key genes in the ceRNA network and important immune cells. Multiple external data sets are used to test the expression of key biomarkers. We constructed prognostic risk models of ceRNA and immune cells, which included 9 differentially expressed mRNAs and 2 types of immune cells. It was discovered from the co-expression analysis that a pair of important biomarkers were associated with the prognosis of oral cancer. T cells regulatory and CGNL1 (R = 0.39, P < .001) showed a significant positive correlation. External data set validation also supports this result. In this study, we found that some crucial ceRNAs (GGCT, TRPS1, CGNL1, HENMT1, LCE3A, S100A8, ZNF347, TMEM144, TMEM192) and immune cells (T cells regulatory and Eosinophils) may be related to the prognosis of oral cancer.

Immunology of Oral Squamous Cell Carcinoma-A Comprehensive Insight with Recent Concepts

This review aims to understand the concept of oral cancer immunology through the notion of immune profiling, immunoediting and immunotherapy, and to gain knowledge regarding its application for the management of oral cancer patients. Oral cancer is an immunogenic tumor where the cells of the tumor microenvironment play an important role in tumorigenesis. Understanding the mechanism of these modulations can help design immunotherapeutic strategies in oral cancer patients. This article gives an overview of immunomodulation in the oral cancer tumor microenvironment, with concepts of immune profiling, immunoediting and immunotherapy. English literature searches via Google Scholar, Web of Science, EBSCO, Scopus, and PubMed database were performed with the key words immunology, tumor microenvironment, cells, cross talk, immune profiling, biomarkers, inflammation, gene expression, techniques, immunoediting, immunosurveillance, tumor escape, immunotherapy, immune checkpoint inhibitors, vaccines in cancer, oral cancer, and head and neck cancer. Original research articles, reviews, and case reports published from 2016-2021 (n = 81) were included to appraise different topics, and were discussed under the following subsections. Literature published on oral cancer immunology reveals that oral cancer immune profiling with appropriate markers and techniques and knowledge on immunoediting concepts can help design and play an effective role in immunotherapeutic management of oral cancer patients. An evaluation of oral cancer immunology helps to determine its role in tumorigenesis, and immunotherapy could be the emerging drift in the effective management of oral cancer.

Molecular Crosstalk between the Immunological Mechanism of the Tumor Microenvironment and Epithelial–Mesenchymal Transition in Oral Cancer

Oral cancer is a significant non-communicable disease affecting both emergent nations and developed countries. Squamous cell carcinoma of the head and neck represent the eight major familiar cancer types worldwide, accounting for more than 350,000 established cases every year. Oral cancer is one of the most exigent tumors to control and treat. The survival rate of oral cancer is poor due to local invasion along with recurrent lymph node metastasis. The tumor microenvironment contains a different population of cells, such as fibroblasts associated with cancer, immune-infiltrating cells, and other extracellular matrix non-components. Metastasis in a primary site is mainly due to multifaceted progression known as epithelial-to-mesenchymal transition (EMT). For the period of EMT, epithelial cells acquire mesenchymal cell functional and structural characteristics, which lead to cell migration enhancement and promotion of the dissemination of tumor cells. The present review links the tumor microenvironment and the role of EMT in inflammation, transcriptional factors, receptor involvement, microRNA, and other signaling events. It would, in turn, help to better understand the mechanism behind the tumor microenvironment and EMT during oral cancer.

B-Cell-Based Immunotherapy: A Promising New Alternative

The field of immunotherapy has undergone radical conceptual changes over the last decade. There are various examples of immunotherapy, including the use of monoclonal antibodies, cancer vaccines, tumor-infecting viruses, cytokines, adjuvants, and autologous T cells carrying chimeric antigen receptors (CARs) that can bind cancer-specific antigens known as adoptive immunotherapy. While a lot has been achieved in the field of T-cell immunotherapy, only a fraction of patients (20%) see lasting benefits from this mode of treatment, which is why there is a critical need to turn our attention to other immune cells. B cells have been shown to play both anti- and pro-tumorigenic roles in tumor tissue. In this review, we shed light on the dual nature of B cells in the tumor microenvironment. Furthermore, we discussed the different factors affecting the biology and function of B cells in tumors. In the third section, we described B-cell-based immunotherapies and their clinical applications and challenges. These current studies provide a springboard for carrying out future mechanistic studies to help us unleash the full potential of B cells in immunotherapy.

Protein Kinase D3 Promotes the Reconstruction of OSCC Immune Escape Niche Via Regulating MHC-I and Immune Inhibit Molecules Expression

Protein kinase D3 (PKD3) has been involved in various aspects of tumorigenesis and progression in many kinds of cancer types. However, whether PKD3 regulates immune escape in tumor microenvironment is rarely reported. Here, we explored the function and mechanism of PKD3 in reconstructing the immune escape niche of oral squamous cell carcinoma (OSCC). Both the Western blotting analysis in OSCC cells and the gene expression correlation analysis from The Cancer Genome Atlas shows that the expression of Fas and programmed cell death-ligand 1 (PD-L1) was positively correlated with PKD3, while major histocompatibility complex-I (MHC-I) was negatively correlated with PKD3. Knockdown of PKD3 significantly decreased the expression of Fas and PD-L1 and increased the expression of MHC-I. Furthermore, when PKD3 was overexpressed in oral precancerous cells, Fas, PD-L1, and MHC-I showed an opposite trend to that observed when PKD3 was knocked down. In addition, PKD3 knockdown decreased the secretion of transforming growth factor β, CC-chemokine ligand 21, interleukin-10 by OSCC cells. Finally, the tumor cell antigen, which was extracted from PKD3 knockdown OSCC cells, significantly induced the growth and activation of T lymphocytes. These results demonstrate that PKD3 promotes the immune escape of OSCC cells by regulating the expression of Fas, PD-L1, MHC-I, transforming growth factor β, CC-chemokine ligand 21, interleukin-10, and plays a key role in reconstructing the tumor immune escape niche.

DDX3 modulates the tumor microenvironment via its role in endoplasmic reticulum-associated translation

Using antibody arrays, we found that the RNA helicase DDX3 modulates the expression of secreted signaling factors in oral squamous cell carcinoma (OSCC) cells. Ribo-seq analysis confirmed amphiregulin (AREG) as a translational target of DDX3. AREG exerts important biological functions in cancer, including promoting cell migration and paracrine effects of OSCC cells and reprogramming the tumor microenvironment (TME) of OSCC in mice. DDX3-mediated translational control of AREG involves its 3′-untranslated region. Proteomics identified the signal recognition particle (SRP) as an unprecedented interacting partner of DDX3. DDX3 and SRP54 were located near the endoplasmic reticulum, regulated the expression of a common set of secreted factors, and were essential for targeting AREG mRNA to membrane-bound polyribosomes. Finally, OSCC-associated mutant DDX3 increased the expression of AREG, emphasizing the role of DDX3 in tumor progression via SRP-dependent, endoplasmic reticulum-associated translation. Therefore, pharmacological targeting of DDX3 may inhibit the tumor-promoting functions of the TME.

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DDX3-AREG axis promotes cancer progression through microenvironment remodeling

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DDX3 activates AREG translation via binding to its 3′ UTR

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DDX3 interacts with the signal recognition particle (SRP)

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DDX3-SRP-mediated mRNA recruitment assists ER-associated translation

Interleukin-6 and Interleukin-8 Regulate STAT3 Activation Migration/Invasion and EMT in Chrysophanol-Treated Oral Cancer Cell Lines

The tumor microenvironment plays a critical role in the control of metastasis. The epithelial–mesenchymal transition (EMT) is strongly associated with tumor metastasis, and consists of several protein markers, including E-cadherin and vimentin. We discovered that chrysophanol causes oral cancer cell apoptosis and the inhibition of migration/invasion and EMT. However, the detailed mechanisms of chrysophanol and its role in oral cancer with respect to the tumor microenvironment remain unknown. In the clinic, proinflammatory cytokines, such as IL-6 and IL-8, exhibit a higher expression in patients with oral cancer. However, the effect of chrysophanol on the production of IL-6 and IL-8 is unknown. We evaluated the expression of IL-6 and IL-8 in human SAS and FaDu oral cancer cell lines in the presence or absence of chrysophanol. The migration and invasion abilities were also determined using a Boyden chamber assay. Our results showed that treatment with chrysophanol significantly decreased the expression of IL-6 and IL-8, as well as the invasion ability of oral cancer cells. Moreover, chrysophanol also attenuated the EMT by increasing the expression of E-cadherin and reducing the expression of vimentin. Mechanistically, chrysophanol inhibited IL-6- and IL-8-induced invasion and STAT3 phosphorylation. IL-6 and IL-8 promote EMT and cell invasion, which is potentially related to the STAT3 signaling pathway in oral cancer. These findings provide insight into new aspects of chrysophanol activity and may contribute to the development of new therapeutic strategies for oral cancer.

GP88/PGRN Serum Levels Are Associated with Prognosis for Oral Squamous Cell Carcinoma Patients

Simple Summary

An oral squamous cell carcinoma (OSCC) is a tumor of the oral cavity that has a five-year survival rate of only around 50%. As this rate has not increased in recent decades, despite improvements in diagnosis and therapy, novel, easily accessible biomarkers for prognosis assessment are still needed. In our study, we measured the growth factor protein progranulin/GP88 in the serum of OSCC patients and demonstrated that an increased serum GP88 level is associated with a better prognosis for the OSCC patients in our study group. Furthermore, serum GP88 levels were not significantly associated with age, sex, or the tumor’s histological features, indicating that serum GP88 levels may be an independent predictor of an individual OSCC patient’s prognosis. These findings may help to improve therapy management of an OSCC in personalized medicine.

Abstract

Progranulin (PGRN)/GP88 is a growth factor that is expressed in a wide range of tumor tissues. The secreted form is involved in various biological processes including proliferation and inflammation. In several tumor types, the serum GP88 level is associated with a patient’s prognosis; however, data for oral squamous cell carcinomas (OSCCs) have not yet been reported. We measured the serum GP88 levels in 96 OSCC patients by an enzyme immunosorbent assay (EIA) and correlated these data with clinicopathological parameters and patient outcomes. The GP88 levels in the serum of OSCC patients and healthy volunteers were comparable. In OSCC patients, the levels did not correlate with age, sex, or TNM status. In a Kaplan–Meier survival analysis, a serum GP88 level < 68 ng/mL was significantly associated with worsened survival (p = 0.0005, log-rank-test) as well as in uni- and multivariate Cox regression analyses (RR = 4.6 [1.6–12.9], p = 0.004 and RR = 4.2 [1.2–12.0], p = 0.008). This effect was predominant in OSCC patients older than 60.5 years (p = 0.027), while in younger patients no significant association between serum GP88 levels and prognosis could be observed. Altogether, lower serum GP88 levels are significantly associated with a worsened outcome for an OSCC and may be an interesting candidate for risk stratification during OSCC therapy.

CircKRT1 drives tumor progression and immune evasion in oral squamous cell carcinoma by sponging miR-495-3p to regulate PDL1 expression

Regulatory functions of circRNAs by targeting the micro RNA (miRNA)/mRNA axis have been increasingly found in oral squamous cell carcinoma (OSCC). CircRNA keratin 1 (CircKRT1) and miR-495-3p were dysregulated in OSCC. Programmed death ligand 1 (PDL1) was an important immunotherapeutic molecule in OSCC. Our objective was to explore whether circKRT1 could regulate cancer progression and immune evasion in OSCC by affecting the miR-495-3p/PDL1 axis. RNA expression was examined by quantitative real-time polymerase chain reaction. All protein levels were detected by western blot. OSCC cell growth was assessed by CCK-8 and colony formation assays. Cell migratory and invasive abilities were evaluated by transwell assay. CD8⁺ T-cell cytotoxicity was determined via lactate dehydrogenase assay. CD8⁺ T-cell percentage and apoptosis were analyzed by flow cytometry. Target screening was performed by Veen Diagram and RNA pull-down assay. Target binding was verified using dual-luciferase reporter and RNA immunoprecipitation assays. A xenograft in mice was conducted for in vivo experiment. CircKRT1 and PDL1 were highly expressed in OSCC tissues and cells. CircKRT1 knockdown repressed OSCC cell growth, migration, invasion, epithelial-mesenchymal transition, and CD8⁺ T-cell apoptosis, but enhanced CD8⁺ T cytotoxicity and percentage. The inhibitory effects of circKRT1 downregulation on OSCC progression and immune evasion were related to PDL1 expression inhibition. CircKRT1 sponged miR-495-3p and miR-495-3p targeted PDL1. OSCC progression and immune evasion were regulated by circKRT1 via the miR-495-3p/PDL1 axis. CircKRT1 also facilitated OSCC progression in vivo by regulating miR-495-3p and PDL1. This study clarified that circKRT1 worked as a miR-495-3p sponge to regulate PDL1, consequently affecting cancer progression and immune evasion in OSCC.

Comparison of Androgen Receptor, VEGF, HIF-1, Ki67 and MMP9 Expression between Non-Metastatic and Metastatic Stages in Stromal and Tumor Cells of Oral Squamous Cell Carcinoma

Objectives: Oral squamous cell carcinoma (OSCC) is the most common oral malignancy with low survival as it is very often diagnosed at an advanced stage, which is why the accurate profiling of the tumor is essential. The aim of this study was to, for the first time, compare in OSCC the frequency of AR, VEGF, MMP9, HiF1beta and Ki67 between the non-metastatic and metastatic disease. Materials and Methods: In the study, 96 non-metastatic and 91 metastatic OSCC patients were analysed for AR, VEGF, MMP9, HiF1beta and Ki67 levels by immunohistochemistry. Results: All of the tested biomarkers significantly differed between non-metastatic and metastatic disease. A significant association was found between >/=20% AR positive epithelium cells in cytoplasm, Ki67 and VEGF in cancer stroma. Ki67, HiF1beta, VEGF and MMP9 were significantly associated with TNM stages. Conclusion: Our results show for the first time an interplay between AR, VEGF, MMP9, HiF1beta and Ki67 in OSCC which may contribute to better diagnostics and therapy selection.

Tumor Microenvironment, HLA Class I and APM Expression in HPV-Negative Oral Squamous Cell Carcinoma

Simple Summary

Oral squamous cell carcinoma has developed different strategies to escape from T-cell-mediated immune surveillance, which is mediated by changes in the composition of cellular and soluble components of the tumor microenvironment as well as an impaired expression of molecules of the antigen processing machinery leading to a downregulation of HLA class I surface antigens. In depth characterization of these escape mechanisms might help to develop strategies to overcome this tolerance. In this study, human papilloma virus negative oral squamous cell carcinoma lesions were analyzed regarding the protein expression of major components of the HLA class I antigen processing/presentation pathway in correlation to the intra-tumoral immune cell composition, IFN-γ signaling and clinical parameters, which was further confirmed by bioinformatics analyses of datasets obtained from The Cancer Genome Atlas. This novel knowledge could be used for optimizing the design of immunotherapeutic approaches of this disease.

Abstract

Progression of oral squamous cell carcinoma (OSCC) has been associated with an escape of tumor cells from the host immune surveillance due to an increased knowledge of its underlying molecular mechanisms and its modulation by the tumor microenvironment and immune cell repertoire. In this study, the expression of HLA class I (HLA-I) antigens and of components of the antigen processing machinery (APM) was analyzed in 160 pathologically classified human papilloma virus (HPV)-negative OSCC lesions and correlated to the intra-tumoral immune cell response, IFN-γ signaling and to the patient’s outcome. A heterogeneous but predominantly lower constitutive protein expression of HLA-I APM components was found in OSCC sections when compared to non-neoplastic cells. Tumoral HLA-I APM component expression was further categorized into the three major phenotypes HLA-I^high/APM^high, HLA-I^low/APM^low and HLA-I^{discordant high/low}/APM^high. In the HLA-I^high/APM^high group, the highest frequency of intra-tumoral CD8⁺ T cells and lowest number of CD8⁺ T cells close to FoxP3⁺ cells were found. Patients within this group presented the most unfavorable survival, which was significantly evident in stage T2 tumors. Despite a correlation with the number of intra-tumoral CD8⁺ T cells, tumoral JAK1 expression as a surrogate marker for IFN-γ signaling was not associated with HLA-I/APM expression. Thus, the presented findings strongly indicate the presence of additional factors involved in the immunomodulatory process of HPV-negative OSCC with a possible tumor-burden-dependent complex network of immune escape mechanisms beyond HLA-I/APM components and T cell infiltration in this tumor entity.

Hypoxia, endoplasmic reticulum stress and chemoresistance: dangerous liaisons

Solid tumors often grow in a micro-environment characterized by < 2% O₂ tension. This condition, together with the aberrant activation of specific oncogenic patwhays, increases the amount and activity of the hypoxia-inducible factor-1α (HIF-1α), a transcription factor that controls up to 200 genes involved in neoangiogenesis, metabolic rewiring, invasion and drug resistance. Hypoxia also induces endoplasmic reticulum (ER) stress, a condition that triggers cell death, if cells are irreversibly damaged, or cell survival, if the stress is mild.Hypoxia and chronic ER stress both induce chemoresistance. In this review we discuss the multiple and interconnected circuitries that link hypoxic environment, chronic ER stress and chemoresistance. We suggest that hypoxia and ER stress train and select the cells more adapted to survive in unfavorable conditions, by activating pleiotropic mechanisms including apoptosis inhibition, metabolic rewiring, anti-oxidant defences, drugs efflux. This adaptative process unequivocally expands clones that acquire resistance to chemotherapy.We believe that pharmacological inhibitors of HIF-1α and modulators of ER stress, although characterized by low specificty and anti-cancer efficacy when used as single agents, may be repurposed as chemosensitizers against hypoxic and chemorefractory tumors in the next future.

Hypoxic Transformation of Immune Cell Metabolism Within the Microenvironment of Oral Cancers

Oral squamous cell carcinoma (OSCC) includes tumors of the lips, tongue, gingivobuccal complex, and floor of the mouth. Prognosis for OSCC is highly heterogeneous, with overall 5-year survival of ~50%, but median survival of just 8-10 months for patients with locoregional recurrence or metastatic disease. A key feature of OSCC is microenvironmental oxygen depletion due to rapid growth of constituent tumor cells, which triggers hypoxia-associated signaling events and metabolic adaptations that influence subsequent tumor progression. Better understanding of leukocyte responses to tissue hypoxia and onco-metabolite expression under low-oxygen conditions will therefore be essential to develop more effective methods of diagnosing and treating patients with OSCC. This review assesses recent literature on metabolic reprogramming, redox homeostasis, and associated signaling pathways that mediate crosstalk of OSCC with immune cells in the hypoxic tumor microenvironment. The likely functional consequences of this metabolic interface between oxygen-starved OSCC and infiltrating leukocytes are also discussed. The hypoxic microenvironment of OSCC modifies redox signaling and alters the metabolic profile of tumor-infiltrating immune cells. Improved understanding of heterotypic interactions between host leukocytes, tumor cells, and hypoxia-induced onco-metabolites will inform the development of novel theranostic strategies for OSCC.

A Review on Role of Arecoline and Its Metabolites in the Molecular Pathogenesis of Oral Lesions with an Insight into Current Status of Its Metabolomics

Areca nut consumption is a popular habit in Southeast Asian countries. One of the important biologically active alkaloids of areca nut is arecoline, which plays a role in mediating the development of several pathologies of the primary exposure site, the oral cavity. Studies on the metabolism of arecoline revealed the formation of several metabolites which themselves might be toxic. Moreover, polymorphisms in genes encoding enzymes involved in the metabolism of arecoline might predispose an organism towards the development of oral cancer. The present review tries to accumulate all the relevant existing literature and then elucidate the molecular mechanism by which arecoline plays a role in the development of oral submucous fibrosis and oral cancer. Existing information regarding arecoline metabolism, enzymes involved in the metabolic process and biological effects of the metabolites of arecoline have also been compiled and compared to study the toxicity of metabolites with its parent compound arecoline and whether they play any role in the pathogenesis of oral cancer mediated by areca nut consumption. A repertoire of molecular targets has come up in the discussion whose expression profile is perturbed by arecoline. Construction of induction cascade from existing literature has given an idea about the process of molecular pathogenesis. The summarized and analysed data can help to determine the molecular mechanism and drug targets, which in turn could be helpful in the prevention or treatment of these pathological conditions. It also brings into light areas where further research needs to be directed.

Prognostic impact of cytoplasmatic EGFR upregulation in patients with oral squamous cell carcinoma: A pilot study

In various tumors, epidermal growth factor-receptor (EGFR) serves a role in tumorigenesis and has an impact on survival. Usually the EGF-receptor is located on the surface of the cell membrane and is involved in various signaling pathways. The dimerization of EGFR with other ErbB family proteins, such as HER2, is important for the tumor progression. Nevertheless, a second EGFR-associated signaling pathway appears to be important for tumor cells, which is cytoplasmic/nuclear EGFR. The present study examined the influence of membranous or cytoplasmic localized EGFR on the prognosis of patients with oral squamous cell carcinoma (OSCC). Slides from 45 OSCC tumor samples were stained against EGFR using immunohistochemistry and analysed by the Remmele score system. The association with histopathological parameters and survival data was analyzed. Cytoplasmatic EGFR localization was identified as an independent predictive biomarker for overall survival in the examined OSCC cohort according to multivariate Cox regression analysis. Positive cytoplasmatic EGFR staining was correlated with a higher risk of early death (RR=3.0; P=0.035), while membranous EGFR localization did not affect patient survival. To the best of our knowledge, the present study is the first study to demonstrate that cytoplasmatic-localized EGFR is an independent prognostic biomarker for the overall survival of patients with OSCC.

Mechanisms of resistance to immune checkpoint inhibitors and strategies to reverse drug resistance in lung cancer

In recent years, the research of immune checkpoint inhibitors has made a great breakthrough in lung cancer treatment. Currently, a variety of immune checkpoint inhibitors have been applied into clinical practice, including antibodies targeting the programmed cell death-1, programmed cell death-ligand 1, and cytotoxic T-lymphocyte antigen 4, and so on. However, not all patients can benefit from the treatment. Abnormal antigen presentation, functional gene mutation, tumor microenvironment, and other factors can lead to primary or secondary resistance. In this paper, we reviewed the molecular mechanism of immune checkpoint inhibitor resistance and various combination strategies to overcome resistance, in order to expand the beneficial population and enable precision medicine.

Current Understanding of the HIF-1-Dependent Metabolism in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is the 10th most frequent human malignancy and is thus a global burden. Despite some progress in diagnosis and therapy, patients’ overall survival rate, between 40 and 55%, has stagnated over the last four decades. Since the tumor node metastasis (TNM) system is not precise enough to predict the disease outcome, additive factors for diagnosis, prognosis, prediction and therapy resistance are urgently needed for OSCC. One promising candidate is the hypoxia inducible factor-1 (HIF-1), which functions as an early regulator of tumor aggressiveness and is a key promoter of energy adaptation. Other parameters comprise the composition of the tumor microenvironment, which determines the availability of nutrients and oxygen. In our opinion, these general processes are linked in the pathogenesis of OSCC. Based on this assumption, the review will summarize the major features of the HIF system-induced activities, its target proteins and related pathways of nutrient utilization and metabolism that are essential for the initiation, progression and therapeutic stratification of OSCC.

FoxP3+ regulatory T cells in oral tongue squamous cell carcinoma in young and older patients

Regulatory T (Treg) cells can suppress antitumor immune response, but little is known about possible age-related differences in the number of these cells in the microenvironment of oral tongue squamous cell carcinoma (OTSCC). The aim of this study was to determine the number of FoxP3+ Treg cells in the microenvironment of OTSCC in young (≤ 45 years) and older (≥ 60 years) patients, and to correlate the findings with clinicopathological parameters (sex, tumor size/extent, regional lymph node metastasis, clinical staging, and histopathological grade of malignancy). Forty-eight OTSCCs (24 diagnosed in young patients and 24 diagnosed in older patients) were selected. Lymphocytes exhibiting nuclear immunopositivity for FoxP3 were quantified at the tumor invasive front and the results were analyzed statistically using the non-parametric Mann-Whitney test. FoxP3+ lymphocytes were observed in all cases assessed. The number of FoxP3+ lymphocytes in OTSCC tended to be higher in older patients (p = 0.055). Analysis of OTSCC in males and in early clinical stages revealed a higher number of Treg cells in older patients than in young ones (p < 0.05). In older patients, the number of Treg cells tended to be higher in smaller tumors (p = 0.079). Tumors with intense inflammatory infiltrate exhibited a larger number of Treg cells, both in young (p = 0.099) and older patients (p = 0.005). The results suggest a greater participation of Treg cells in immunoinflammatory responses in the microenvironment of OTSCC in older patients, particularly in males and in early stages.

Identification of an Immune Score-Based Gene Panel with Prognostic Power for Oral Squamous Cell Carcinoma

Background

Oral squamous cell carcinoma (OSCC) is the sixth most prevalent cancer worldwide, with low 5-year survival rate. To identify novel prognostic markers for OSCC and determine the immune and stromal landscape of OSCC, a risk signature for OSCC patients was constructed in this study.

Material/Methods

Immune and stromal scores for OSCC samples from the Genomic Data Commons Data Portal were computed to delineate the tumor microenvironment landscape of oral cancer based on the Estimation of STromal and Immune cells in MAlignant Tumours using Expression data algorithm. An immune score-based risk signature was constructed by combining random forest and support vector machine methods. Correlation analysis of risk signature gene expression and immune cell infiltration was conducted, and the distinguishing power of individual signature genes was evaluated by analyzing receiver operating characteristics (ROC) curves. Differentially enriched pathways between high and low risk groups were investigated via gene set variation analysis. ROC curves were plotted for signature genes to examine their ability to distinguish the recurrence and survival status of OSCC patients from GSE84846.

Results

An immune score-related risk signature composed of ARMH1, F2RL2, AC004687.1, COL6A5, AC008750.1, RAB19, CRLF2, GRIP2, and FAM162B performed well in the prognostic stratification of OSCC patients and could effectively distinguish their survival status. Lists of pathways, including cytokine–cytokine receptor interaction and cell adhesion molecules displayed remarkable differential enrichment between high and low risk OSCC patients.

Conclusions

An immune score-based risk signature constructed presently may be useful to decide appropriate treatment options for individual OSCC patients.

Syringic acid induces apoptosis in human oral squamous carcinoma cells through mitochondrial pathway

Background:

Syringic acid (SA) has long been used as traditional medicine and is known to have antioxidant, hepatoprotective, neuroprotective and anticancer effects. Studies regarding the anticancer effect of SA against squamous carcinoma cell (SCC)-25, human oral SCC (OSCC) line has not been studied.

Aim:

This study was aimed to evaluate the cytotoxic potentials of SA in SCC-25 cells.

Materials and Methods:

Cytotoxic effect of SA was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylte trazolium bromide assay, using concentrations of 25 and 50 μM/mL for 24 h. At the end of the treatment period, apoptotic markers such as caspase 3 and 9, bcl-2, bax and cytochrome c were evaluated by semiquantitative reverse transcription-polymerase chain reaction. SA-induced morphological changes were investigated by acridine orange/ethidium bromide dual staining.

Results:

SA inhibited the proliferation and induced cytotoxicity in SCC-25 cells in a concentration-dependent manner. SA treatment caused apoptosis-related morphological changes as evidenced by the dual staining and the modulation of apoptotic marker gene expressions. SA treatments modulated bcl-2/bax homeostasis and increased the expressions of cytochrome c and caspases 3 and 9.

Conclusion:

SA specifically induces cell death and inhibits the proliferation in OSCC cells through intrinsic/mitochondrial apoptosis pathway, suggesting that SA may be an effective agent for the treatment of human OSCC.

Neck Disability and Swallowing Function in Posttreatment Head and Neck Cancer Patients

Objective

To examine the relationship between symptoms of neck disability and swallowing dysfunction among head and neck cancer (HNC) survivors.

Study Design

Cross-sectional analysis.

Setting

Single-center, university-affiliated HNC survivorship clinic.

Subjects and Methods

Survivors’ patient-reported symptoms of neck disability and swallowing dysfunction were prospectively collected from March 2017 to May 2018. Neck disability and swallowing dysfunction were measured using the Neck Disability Index and Eating Assessment Tool (EAT-10), respectively. Linear regression was used to analyze the association between neck disability and swallowing dysfunction.

Results

A total of 179 survivors, predominantly male (n = 130, 72.6%) with an average age of 64.64 ± 9.91 years, were included in the analysis. Primary cancer sites were oropharynx (n = 85, 47.5%), oral cavity (n = 59, 33.0%), and larynx/hypopharynx (n = 35, 19.5%). Mean EAT-10 score was 10.07 ± 10.89 (range = 0-40; >2 indicative of swallowing dysfunction). Survivors treated for early stage cancer had lower EAT-10 scores than those with advanced stage (early = 3.55 ± 7.46; advanced = 11.95 ± 11.02, P < .001). After controlling for age, time since treatment, American Joint Committee on Cancer stage, and treatment modality, the EAT-10 score for patients with mild neck disability was 6.88 (95% confidence interval [CI], 3.71-10.06; P < .001) points higher than those without neck disability, and the score for those with moderate-complete neck disability was 13.65 (95% CI, 9.47-17.83; P < .001) points higher than those without neck disability.

Conclusions

Swallowing dysfunction is a commonly recognized effect of HNC treatment. The prevalence and burden of neck disability are shown to be highly correlated with swallowing dysfunction. These results support the need for comprehensive, multidisciplinary rehabilitation interventions for patients with HNC.

Transcriptome analysis reveals the link between lncRNA-mRNA co-expression network and tumor immune microenvironment and overall survival in head and neck squamous cell carcinoma

Background

As the sixth most common cancer worldwide, head and neck squamous cell carcinoma (HNSCC) develops visceral metastases during the advanced stage of the disease and exhibits a low five-year survival rate. The importance of tumor microenvironment (TME) in tumor initiation and metastasis is widely recognized. In addition, accumulating evidence indicates that long non-coding RNA (lncRNA) is involved in crosstalk between TME and tumor cells. However, the lncRNA-associated regulators modulating the HNSCC microenvironment and progression remain largely unknown.

Methods

The publicly available transcriptome data and matched clinical HNSCC data were collected from The Cancer Genome Atlas (TCGA). Immune scores (ISs) and stromal scores (SSs) of HNSCC TME were calculated using ESTIMATE algorithm. Weighted gene co-expression network analysis (WGCNA) was conducted to determine the co-expressed lncRNAs and protein-coding mRNAs.

Results

Results showed that the high IS HNSCC male patient subgroup exhibited improved survival. Additionally, we identified 169 lncRNAs and 825 protein-coding mRNAs that were differentially expressed in high IS HNSCC samples, with the up-regulated mRNAs displaying enrichment in immune-related biological processes. Notably, we identified a high co-expression lncRNA-mRNA module (i.e., purple module) that showed strong correlation with ISs. This module contained 79 lncRNAs and 442 mRNAs, including 26 lncRNAs and 215 mRNAs showing association between expression and male HNSCC survival. Consistently, 207 of the 215 mRNAs were up-regulated in high IS HNSCC group and were enriched in immune-related signaling pathways. Based on bioinformatics analyses and previous functional assays, certain lncRNAs (e.g., AL365361.1 and PCED1B-AS1) in the purple module likely contributed to the modification of tumor immune microenvironment (TIME) in the high IS HNSCC patients, achieved by regulating transcription of abundant immune-related genes (e.g., CCR7 and TLR8).

Conclusions

In summary, we ascertained a HNSCC male patient subgroup that displayed high ISs and good survival probability. We identified hundreds of genes with specific expression patterns in this HNSCC subgroup as well as a highly co-expressed lncRNA-mRNA module with great potential for the modulation of TIME of HNSCC. Our study provides evidence of a link between the lncRNA-associated gene network, TIME, and HNSCC progression, and highlights potential therapeutic targets for this disease.

Overexpression of Platelet-Derived Growth Factor and Its Receptor Are Correlated with Oral Tumorigenesis and Poor Prognosis in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a cancerous disease with poor prognosis. According to the statistics, the 5-year survival rate has not improved significantly over the past 20 years. The platelet-derived growth factor (PDGF) and its signaling pathway is a key regulator of angiogenesis and tumorigenesis. High level of PDGF and its receptor (PDGFR) have been reported in several types of malignancies. In this study, we investigated the relationship of the molecular expression levels of PDGF and PDGFR with clinicopathological parameters in OSCC. To this end, we measured the mRNA and protein levels of PDGF and PDGFR by real-time quantitative PCR (qRT-PCR), immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA), respectively. We found positive correlations of the mRNA levels of PDGFA, PDGFB, and PDGFRB with lymph node metastasis and poor overall survival (OS). High expression of PDGF, PDGFRA, and PDGFRB were remarkably associated with lymph node metastasis and poor OS, as determined by immunohistochemistry. Preoperative serum levels of PDGF-AA and PDGF-BB had a positive correlation with preoperative platelet count. Elevated serum levels of PDGF-AA. PDGF-BB, and platelet count correlated with lymph node metastasis and an unfavorable outcome. In multivariate Cox regression analysis, PDGFA mRNA, PDGFB mRNA, PDGFRB mRNA, PDGF immunoexpression, PDGFRB immunoexpression, serum PDGF-AA, serum PDGF-BB, and platelet count emerged as significant independent prognostic factors for OS. In vitro, we found that elevated PDGF promotes colony formation, migration, and invasiveness of SAS and OECM-1 cancer cell lines. Our results suggest that the expression level of serum PDGF has the potential to become a useful diagnostic marker for the prognosis of OSCC. In addition, PDGFR should be considered as a potential therapeutic target for OSCC. Furthermore, research should be undertaken to elucidate the role of PDGF and PDGFR regarding the behavior of tumor cells in OSCC.

CCL21/CCR7 interaction promotes EMT and enhances the stemness of OSCC via a JAK2/STAT3 signaling pathway

Chemokines and their receptors show a strong relationship with poor clinical outcomes in various cancers. However, their underlying mechanisms remain to be fully elucidated. In our research, we found C-C chemokine receptor 7 (CCR7) and its ligand chemokine ligand 21 (CCL21) were abnormally abundant in oral squamous cell carcinoma (OSCC) tissues, and CCR7 expression was correlated with poor prognosis of OSCC. After exogenous CCL21 stimulation, epithelial-mesenchymal transition (EMT) was promoted in OSCC cells, and cancer stem cell-related markers CD133, CD44, BMI1, ALDH1A1, and OCT4 increased. The migration, invasion, tumorsphere formation, and colony formation abilities of OSCC cells were enhanced, indicating that the stemness of OSCC cells was also improved. The knockdown and overexpression of CCR7 efficiently affected the CCL21-induced EMT and stemness of OSCC cells. When treated with CCL21, the phospho-JAK2 and phospho-STAT3 markedly increased. The inhibitor of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) significantly suppressed CCL21-induced EMT and stemness of OSCC cells. In conclusion, CCL21/CCR7 axis regulated EMT progress and promoted the stemness of OSCC by activating the JAK2/STAT3 signaling pathway. CCL21/CCR7 might be an effective target for OSCC prevention and treatment.

The expression and prognostic impact of proinflammatory cytokines and their associations with carcinogens in oropharyngeal squamous cell carcinoma

In oropharyngeal squamous cell carcinoma (OPSCC), the relationships between immune responses, carcinogens, and prognoses are not clarified yet. Here, we retrospectively reviewed the pathology samples of 46 OPSCC patients, and used p16 to determine their human papillomavirus (HPV) status. The Cancer Genome Atlas (TCGA) database was also analyzed for further comparison. The immunofluorescence staining of proinflammatory cytokines showed that high interferon gamma (IFNγ; T helper 1; Th1), low interleukin 4 (IL4; T helper 2; Th2), low thymic stromal lymphopoietin (TSLP; Th2), and low transforming growth factor beta (TGFβ; T regulatory; Treg) expressions were good prognostic factors for OPSCC. p16-positive OPSCC showed higher Th1, lower Th2/Treg proinflammatory cytokine expressions, and a better prognosis than p16-negative OPSCC. In smokers alone, although p16-positive OPSCC smokers showed weaker Th2/Treg predominant cytokine expressions than p16-negative OPSCC smokers, the prognoses of both groups were equally poor. As for p16-positive OPSCC patients alone, p16-positive nonsmokers showed a significantly better prognosis than p16-positive smokers, but the immune responses of both groups were all weakly Th2/Treg predominant. Overall, higher Th1 and lower Th2/Treg proinflammatory cytokine expressions are associated with a better prognosis for OPSCC. HPV may be related to increased Th1, decreased Th2/Treg responses, and a good prognosis, while smoking may be related to increased Th2/Treg, decreased Th1 responses, and a poor prognosis in OPSCC. The impact of smoking on immune deviation may be weaker than that of HPV, but the impact of smoking on prognosis may be stronger than that of HPV in OPSCC.

The Oral Microbiota May Have Influence on Oral Cancer

The oral microbiota plays an important role in the human microbiome and human health, and imbalances between microbes and their hosts can lead to oral and systemic diseases and chronic inflammation, which is usually caused by bacteria and contributes to cancer. There may be a relationship between oral bacteria and oral squamous cell carcinoma (OSCC); however, this relationship has not been thoroughly characterized. Therefore, in this study, we compared the microbiota compositions between tumor sites and opposite normal tissues in buccal mucosal of 50 patients with OSCC using the 16S rDNA sequencing. Richness and diversity of bacteria were significantly higher in tumor sites than in the control tissues. Cancer tissues were enriched in six families (Prevotellaceae, Fusobacteriaceae, Flavobacteriaceae, Lachnospiraceae, Peptostreptococcaceae, and Campylobacteraceae) and 13 genera, including Fusobacterium, Alloprevotella and Porphyromonas. At the species level, the abundances of Fusobacterium nucleatum, Prevotella intermedia, Aggregatibacter segnis, Capnocytophaga leadbetteri, Peptostreptococcus stomatis, and another five species were significantly increased, suggesting a potential association between these bacteria and OSCC. Furthermore, the functional prediction revealed that genes involved in bacterial chemotaxis, flagellar assembly and lipopolysaccharide (LPS) biosynthesis which are associated with various pathological processes, were significantly increased in the OSCC group. Overall, oral bacterial profiles showed significant difference between cancer sites and normal tissue of OSCC patients, which might be onsidered diagnostic markers and treatment targets. Our study has been registered in the Chinese clinical trial registry (ChiCTR1900025253, http://www.chictr.org.cn/index.aspx).

Causes and Consequences of A Glutamine Induced Normoxic HIF1 Activity for the Tumor Metabolism

The transcription factor hypoxia-inducible factor 1 (HIF1) is the crucial regulator of genes that are involved in metabolism under hypoxic conditions, but information regarding the transcriptional activity of HIF1 in normoxic metabolism is limited. Different tumor cells were treated under normoxic and hypoxic conditions with various drugs that affect cellular metabolism. HIF1α was silenced by siRNA in normoxic/hypoxic tumor cells, before RNA sequencing and bioinformatics analyses were performed while using the breast cancer cell line MDA-MB-231 as a model. Differentially expressed genes were further analyzed and validated by qPCR, while the activity of the metabolites was determined by enzyme assays. Under normoxic conditions, HIF1 activity was significantly increased by (i) glutamine metabolism, which was associated with the release of ammonium, and it was decreased by (ii) acetylation via acetyl CoA synthetase (ACSS2) or ATP citrate lyase (ACLY), respectively, and (iii) the presence of L-ascorbic acid, citrate, or acetyl-CoA. Interestingly, acetylsalicylic acid, ibuprofen, L-ascorbic acid, and citrate each significantly destabilized HIF1α only under normoxia. The results from the deep sequence analyses indicated that, in HIF1-siRNA silenced MDA-MB-231 cells, 231 genes under normoxia and 1384 genes under hypoxia were transcriptionally significant deregulated in a HIF1-dependent manner. Focusing on glycolysis genes, it was confirmed that HIF1 significantly regulated six normoxic and 16 hypoxic glycolysis-associated gene transcripts. However, the results from the targeted metabolome analyses revealed that HIF1 activity affected neither the consumption of glucose nor the release of ammonium or lactate; however, it significantly inhibited the release of the amino acid alanine. This study comprehensively investigated, for the first time, how normoxic HIF1 is stabilized, and it analyzed the possible function of normoxic HIF1 in the transcriptome and metabolic processes of tumor cells in a breast cancer cell model. Furthermore, these data imply that HIF1 compensates for the metabolic outcomes of glutaminolysis and, subsequently, the Warburg effect might be a direct consequence of the altered amino acid metabolism in tumor cells.

SPARC promotes the proliferation and metastasis of oral squamous cell carcinoma by PI3K/AKT/PDGFB/PDGFRβ axis

Oral squamous cell carcinoma (OSCC) is a highly lethal cancer in the world, and the prognosis of OSCC is poor with a 60% 5-year survival rate in recent decades. Here, we introduced a novel secretory and acid glycoprotein with cysteine rich (secreted protein acidic and rich in cysteine, SPARC), which is correlated with the worst pattern of invasion (WPOI) and prognosis of OSCC. SPARC expression levels were measured in OSCC tissues and normal tissues using quantitative polymerase chain reaction and immunohistochemistry. The influence of SPARC on cell proliferation was examined by cell counting kit-8, colony formation, and Edu tests. Then, the effect of SPARC on the metastasis of OSCC cells was detected by wound healing and transwell migration assays. Next, the biologic characteristics of SPARC shared by STRING were analyzed. Furthermore, the underlying mechanisms were confirmed by western blot analysis. SPARC revealed higher expression in OSCC tissues than nontumor tissues. Higher SPARC expression was correlated with poorer tumor differentiation, poorer WPOI pattern, and significantly and shorter overall survival. Knockdown SPARC significantly restrained OSCC cell growth, migration, and invasion. In addition, bioinformatics analysis found SPARC had a coexpression network with the platelet-derived growth factor-B (PDGFB) and PI3K/AKT signaling pathways with minimal false discovery rate. Furthermore, SPARC promotes OSCC cells metastasis by regulating the expressions of PDGFB, PDGFRβ, p-PDGFRβ , and the PI3K/AKT pathway. Higher SPARC expression was positively correlated with poor WPOI and differentiation in OSCC. SPARC activates the PI3K/AKT/PDGFB/PDGFRβ axis to promote proliferation and metastasis by OSCC cell lines. Therefore, SPARC may be a potential therapeutic target for patients with OSCC.

POM121 is identified as a novel prognostic marker of oral squamous cell carcinoma

Background: The aim of this study was to confirm the role of nuclear pore membrane protein 121(POM121) in oral squamous cell carcinoma and to explore the underlying mechanism. Methods: POM121mRNA and protein expressions were evaluated in OSCC tissues and normal oral tissues by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry. The relationship between POM121 expression and clinical characteristics was analyzed. Bioinformatics analysis was performed to explore the possible mechanisms how POM121 affected OSCC. Results: We confirmed that POM121 mRNA expression in OSCC tissues was significantly higher than that in non-tumorous tissues, as was POM121 protein expression. POM121 expression was associated with distant metastasis and TNM stage. Multivariate analysis confirmed POM121 expression as an independent prognostic factor for OSCC patients. OSCC patients with high POM121 expression had a worse overall survival (OS) compared with patients with low POM121 expression. Bioinformatics analysis indicated POM121 may regulate OSCC through hedgehog and /or p53 signaling pathway. Conclusion: Targeting of POM121 expression levels could provide new diagnostic and therapeutic strategies for OSCC patients.

Impact of combination immunochemotherapies on progression of 4NQO-induced murine oral squamous cell carcinoma

Advanced oral squamous cell carcinomas (OSCC) have limited therapeutic options. Although immune therapies are emerging as a potentially effective alternative or adjunct to chemotherapies, the therapeutic efficacy of combination immune chemotherapies has yet to be determined. Using a 4-nitroquinolone-N-oxide (4NQO) orthotopic model of OSCC in immunocompetent mice, we evaluated the therapeutic efficacy of single- and combined-agent treatment with a poly-epitope tumor peptide vaccine, cisplatin and/or an A2AR inhibitor, ZM241385. The monotherapies or their combinations resulted in a partial inhibition of tumor growth and, in some cases, a significant but transient upregulation of systemic anti-tumor CD8+ T cell responses. These responses eroded in the face of expanding immunoregulatory cell populations at later stages of tumor progression. Our findings support the need for the further development of combinatorial therapeutic approaches that could more effectively silence dominant immune inhibitory pathways operating in OSCC and provide novel, more beneficial treatment options for this tumor.

Expression and Significance of Periostin in Tissues and Serum in Oral Leukoplakia and Squamous Cell Carcinoma

Objective: This study aims to investigate the expression changes of periostin (PN or OSF-2) in oral leukoplakia (OLK) and oral squamous cell carcinoma (OSCC), and analyze its significance in the development of OSCC. Study Design: The expression of periostin was detected from tissue specimens and serum obtained from normal mucosa, OLK and OSCC by immunohistochemistry, enzyme-linked immunosorbent assay, and quantitative polymerase chain reaction. Results: Periostin was significantly overexpressed in OLK and OSCC, when compared with normal controls (p < 0.05). Furthermore, the overexpression of periostin was positively correlated with TNM stage, depth of invasion, and lymph node metastasis (p < 0.05). Conclusion: The overexpression of periostin may be involved in the carcinogenesis process of OLK, which may be used as a marker for detecting OLK. In addition, periostin serum levels can be used as a potential indicator of invasion and a prognosis target for OSCC.

Macrophage-derived CCL22 promotes an immunosuppressive tumor microenvironment via IL-8 in malignant pleural effusion

Immune dysfunction often occurs in malignant pleural effusion (MPE). In our previous study, TGF-β derived predominantly from macrophages plays an important role in impairing T cell cytotoxicity in MPE. Therefore, we aimed to investigate whether other immunoregulatory cells and factors mediated TGF-β secretion from macrophages, involved in the immunosuppressive microenvironment of MPE, and to provide clues for potential immune therapy for MPE as well. We found that CCL22 level in MPE was significantly higher than that in non-malignant pleural effusion. The high level of CCL22 was closely associated with poor survival in MPE patients with lung cancer. CCL22 was dominantly produced by tumor-associated macrophages (TAMs) in MPE. Meanwhile, TAM-derived TGF-β mediated CCL22 expression in TAMs via c-Fos. CCL22 promoted the recruitment of regulatory T cells (Tregs) in MPE. Lastly, Treg-secreted high level of IL-8 further induced TGF-β production from TAMs, and promoted the immunosuppressive tumor microenvironment in MPE. Our results indicate that macrophage-derived CCL22 plays an important role in the immunosuppressive tumor microenvironment via IL-8 in MPE.

Prognostic impact of mRNA levels of LGR5 transcript variants in OSCC patients

Background

The human leucine-rich, repeat-containing G protein-coupled receptor 5 (LGR5) is a stem cell marker in numerous adult tissues and is overexpressed in a large number of human carcinoma including colon cancer, breast cancer and oral squamous cell carcinomas (OSCC). The role of the full length transcript (LGR5FL) in progression and prognosis of several cancers was reported. However, the biological function of three splice variants of LGR5 (LGR5Δ5, LGR5Δ8 and LGR5Δ5–8) has yet to be thoroughly investigated.

Methods

Seventy-eight frozen tumor samples from adult OSCC patients were studied using quantitative real-time TaqMan™ PCR analysis. The mRNA levels of full length LGR5, the splice variant of LGR5 lacking exon 5 (LGR5Δ5), the splice variant of LGR5 lacking exon 8 (LGR5Δ8) and the mRNA level of all known transcript variants together (LGR5all) were quantified and correlated to overall and disease-specific survival of OSCC patients, clinical parameters and the mRNA level of different tumor-associated markers.

Results

An elevated level of tumoral LGR5Δ5 mRNA, but not LGR5FL, LGR5Δ8 or LGR5all mRNA was significantly associated with a poor prognosis for the overall and disease-specific survival of OSCC patients (hazard ratio (HR) = 2.0; p = 0.02; 95% CI: 1.1–3.7; HR = 3.2; p = 0.01; 95% CI: 1.3–8.0; multivariable Cox regression), respectively. Additionally, a higher tumoral level of LGR5Δ5 mRNA in primary tumors was associated with the occurrence of regional lymph node metastases in OSCC patients (odds ratio (OR) = 3.1; p = 0.022; 95% CI: 1.2–7.9; binary logistic regression). Furthermore, the mRNA levels of all investigated LGR5 transcript variants were significantly correlated with the mRNA expression of Wnt-target genes and markers of epithelial-to-mesenchymal transition (EMT).

Conclusion

The mRNA level of the LGR5 splice variant LGR5Δ5 is an independent negative prognostic marker for overall and disease-specific survival and metastasis in OSCC patients. Additionally, we suggest, all LGR5 transcript variants are involved in the EMT process mainly through activating the Wnt-signalling pathway.