Regulatory T cells in oral squamous cell carcinoma

Prognostic Role of Tumor-Infiltrating Lymphocytes in Oral Squamous Cell Carcinoma

BACKGROUND

In oral squamous cell carcinoma (OSCC), the tumor-node-metastasis (TNM) staging system is a significant factor that influences prognosis and treatment decisions for OSCC patients. Unfortunately, TNM staging does not consistently predict patient prognosis and patients with identical clinicopathological characteristics may have vastly different survival outcomes. Host immunity plays an important role in tumor progression but is not included in the TNM staging system. Tumor-infiltrating lymphocytes (TILs) are part of the host immune response that recognizes tumor cells; and the presence of TILs has emerged as potential candidates for prognostic markers for many types of cancers. The present study aims to determine the association of T cell-specific markers (CD3, CD4, CD8, and FOXP3) with clinicopathological characteristics and survival outcomes in OSCC patients. The prognostic value of CD3, CD4, and CD8 will also be evaluated based on tumor stage.

METHODS

Tissue microarrays were constructed containing 231 OSCC cases and analyzed by immunohistochemical staining for the expression of CD3, CD4, CD8, and FOXP3. The expression scores for each marker were correlated with clinicopathological parameters and survival outcomes. The prognostic impact of CD3, CD4 and CD8 were further analyzed based on tumor stage (early or advanced).

RESULTS

CD3, CD4, and CD8 were found to be significantly associated with both overall survival and progression-free survival using univariate analysis. However, none of these markers were found to independently predict the survival outcomes of OSCC using multivariate analysis. Only conventional factors such as nodal status, tumor differentiation and perineural invasion (PNI) were independent predictors of survival outcomes, with nodal status being the strongest independent predictor. Additionally, low CD4 (but not CD3 or CD8) expression was found to identify early-stage OSCC patients with exceptionally poor prognosis which was similar to that of advanced staged OSCC patients.

CONCLUSIONS

TIL markers such as CD3, CD4, CD8, and FOXP3 can predict the survival outcomes of OSCC patients, but do not serve as independent prognostic markers as found with conventional factors (i.e. nodal status, tumor differentiation and PNI). CD4 expression may assist with risk stratification in early-stage OSCC patients which may influence treatment planning and decision making for early-stage OSCC patients.

The Use of Immune Regulation in Treating Head and Neck Squamous Cell Carcinoma (HNSCC)

Immunotherapy has emerged as a promising new treatment modality for head and neck cancer, offering the potential for targeted and effective cancer management. Squamous cell carcinomas pose significant challenges due to their aggressive nature and limited treatment options. Conventional therapies such as surgery, radiation, and chemotherapy often have limited success rates and can have significant side effects. Immunotherapy harnesses the power of the immune system to recognize and eliminate cancer cells, and thus represents a novel approach with the potential to improve patient outcomes. In the management of head and neck squamous cell carcinoma (HNSCC), important contributions are made by immunotherapies, including adaptive cell therapy (ACT) and immune checkpoint inhibitor therapy. In this review, we are focusing on the latter. Immune checkpoint inhibitors target proteins such as programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) to enhance the immune response against cancer cells. The CTLA-4 inhibitors, such as ipilimumab and tremelimumab, have been approved for early-stage clinical trials and have shown promising outcomes in terms of tumor regression and durable responses in patients with advanced HNSCC. Thus, immune checkpoint inhibitor therapy holds promise in overcoming the limitations of conventional therapies. However, further research is needed to optimize treatment regimens, identify predictive biomarkers, and overcome potential resistance mechanisms. With ongoing advancements in immunotherapy, the future holds great potential for transforming the landscape of oral tumor treatment and providing new hope for patients.

Costimulatory Molecules OX40 and OX40L Upregulation in Oral Squamous Cell Carcinoma: A Blood-Based Study

OBJECTIVES

 This research aimed to determine OX40 and OX40L mRNA expression in blood samples of naive oral squamous cell carcinoma (OSCC) patients in different histological grades and clinical stages. The in silico analysis was performed using the STRING database for functional association and a better understanding of the interactions of OX40 and its ligand with other proteins.

MATERIALS AND METHODS

 In this study, we recruited 141 newly diagnosed patients of OSCC. Levels of OX40 and OX40L mRNA expression were explored using real-time quantitative polymerase chain reaction. An in silico tool was also utilized to evaluate the OX40/OX40L interactome.

RESULTS

 The results showed higher OX40 expressional levels in the late stage (23-fold) compared with the early stage (8.5-fold) (p = < 0.001). A similar trend was seen in OX40L mRNA expression, revealing a fold change of 5.8 in the early stage in comparison to 9.9-fold change in the late stage (p = < 0.001). Overexpression of OX40 and OX40L was found in different histological grades (p = 0.005 and p = < 0.001, respectively). Overexpression of OX40 and OX40L was detected in habits such as smoking and paan intake, whereas statistically significant upregulation was observed in the cheek, lip, and alveolus tumors. However, there was no substantial difference in OX40 and OX40L expression based on age or gender. The functional interactions, that is, interactomes of OX40 and OX40L with other proteins have been determined by in silico analysis.

CONCLUSION

 Based on current study findings, despite OX40 and OX40L upregulation in newly diagnosed OSCC patients, it is speculated that the physiological function of these molecules is altered due to immune system exhaustion.

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.

Targeting oral tumor microenvironment for effective therapy

Oral cancers are among the common head and neck malignancies. Different anticancer therapy modalities such as chemotherapy, immunotherapy, radiation therapy, and also targeted molecular therapy may be prescribed for targeting oral malignancies. Traditionally, it has been assumed that targeting malignant cells alone by anticancer modalities such as chemotherapy and radiotherapy suppresses tumor growth. In the last decade, a large number of experiments have confirmed the pivotal role of other cells and secreted molecules in the tumor microenvironment (TME) on tumor progression. Extracellular matrix and immunosuppressive cells such as tumor-associated macrophages, myeloid-derived suppressor cells (MDSCs), cancer-associated fibroblasts (CAFs), and regulatory T cells (Tregs) play key roles in the progression of tumors like oral cancers and resistance to therapy. On the other hand, infiltrated CD4 + and CD8 + T lymphocytes, and natural killer (NK) cells are key anti-tumor cells that suppress the proliferation of malignant cells. Modulation of extracellular matrix and immunosuppressive cells, and also stimulation of anticancer immunity have been suggested to treat oral malignancies more effectively. Furthermore, the administration of some adjuvants or combination therapy modalities may suppress oral malignancies more effectively. In this review, we discuss various interactions between oral cancer cells and TME. Furthermore, we also review the basic mechanisms within oral TME that may cause resistance to therapy. Potential targets and approaches for overcoming the resistance of oral cancers to various anticancer modalities will also be reviewed. The findings for targeting cells and potential therapeutic targets in clinical studies will also be reviewed.

Interleukin-23 receptor defines T helper 1-like regulatory T cells in oral squamous cell carcinoma

BACKGROUND

The immune responses play significant roles in the onset, progression, and outcome of oral squamous cell carcinoma (OSCC). CD4⁺ regulatory T cells (Tregs) significantly impact tumor immunity. However, their role in OSCC development remains elusive.

METHODS

In a carcinogen-induced mouse OSCC model, interleukin-23 receptor (IL-23R) expression on Tregs and Treg function were determined by flow cytometry. IL-23R overexpression in Tregs was achieved by lentiviral infection, followed by evaluation of the expression of Forkhead box P3 (Foxp3), T-bet, retineic-acid-receptor-related orphan nuclear receptor gamma t, and cytokines by flow cytometry. Adoptive transfer assays were applied to analyze the function of IL-23R^- overexpressing Tregs in vivo. The cellular sources of IL-23 were also determined by flow cytometry.

RESULTS

IL-23R^- Tregs and IL-23R⁺ Tregs were found in the tongues but not spleens of OSCC-bearing mice. IL-23R⁺ Tregs expressed lower Foxp3 but higher T-bet than IL-23R^- Tregs. IL-23R^- Tregs produced abundant IL-10 and transforming growth factor (TGF)-β, while IL-23R⁺ Tregs produced lower IL-10 and TGF-β but remarkably higher interferon (IFN)-γ. Furthermore, IL-23R⁺ Tregs possessed more phosphorylated signal transducer and activator of transcription (STAT3) and STAT4 than IL-23R^- Tregs. IL-23R⁺ Tregs were less immunosuppressive than IL-23R^- Tregs, as evidenced by weaker inhibition of activated conventional T cells. IL-23R overexpression in splenic Tregs remarkably reduced the expression of IL-10 and TGF-β but increased IFN-γ expression when Tregs were adoptively transferred into OSCC-bearing mice. In the OSCC microenvironment, macrophages, dendritic cells, and malignant OSCC cells produced IL-23 which might modulate the function of IL-23R⁺ Tregs.

CONCLUSIONS

This study unveils Treg heterogeneity, thus deepening the understanding of Treg biology and tumor immunity in OSCC.

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.

Prognostic signature related to the immune environment of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) prognosis remains poor. Here we aimed to identify an effective prognostic signature for predicting the survival of patients with OSCC. Gene-expression and clinical data were obtained from the Cancer Genome Atlas database. Immune microenvironment-associated genes were identified using bioinformatics. Subtype and risk-score analyses were performed for these genes. Kaplan–Meier analysis and immune cell infiltration level were explored in different subtypes and risk-score groups. The prognostic ability, independent prognosis, and clinical features of the risk score were assessed. Furthermore, immunotherapy response based on the risk score was explored. Finally, a conjoint analysis of the subtype and risk-score groups was performed to determine the best prognostic combination. We found 11 potential prognostic genes and constructed a risk-score model. The subtype cluster 2 and a high-risk group showed the worst overall survival; differences in survival status might be due to the different immune cell infiltration levels. The risk score showed good performance, independent prognostic value, and valuable clinical application. Higher risk scores showed higher Tumor Immune Dysfunction and Exclusion scores, indicating that patients with a high-risk score were less likely to benefit from immunotherapy. Finally, conjoint analysis for the subgroups and risk groups showed the best predictive ability.

Biological implications of the immune factors in the tumour microenvironment of oral cancer

OBJECTIVE

The objective of this review is to decipher the biological implications of the immune factors in the tumour microenvironment in oral cancer. The restoration of balance between tumour tolerance and tumour eradication by the host immune cells is critical to provide effective therapeutic strategies.

DESIGN

The specific role of the stromal and the immune components in oral cancer was reviewed with a tailored search strategy using relevant keywords. The articles were retrieved from bibliometric databases indexed in PubMed, Scopus, and Embase. An in silico analysis was performed to identify potential drug candidates for immunotherapy, by accessing the Drug-Gene Interactions Database (DGIdb) using the rDGIdb package.

RESULTS

There is compelling evidence for the role of the cellular and extracellular components of the tumour microenvironment in inducing immunosuppression and progression of oral cancer. The druggable candidates specifically targeting the immune system are a viable option in the treatment of oral cancer as they can regulate the tumour microenvironment.

CONCLUSION

A complex interaction between the tumour and the immunological microenvironment influences the disease outcome in oral cancer. Targeting specific components of the immune system might be relevant, as immunotherapy may become the new standard of care for oral cancer.

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.

Predictive factors in the treatment of oral squamous cell carcinoma using PD-1/PD-L1 inhibitors

Due to immune impairment and lymphocyte enrichment of oral squamous cell carcinoma (OSCC), anti-PD-1/PD-L1 therapy is regarded as a potential treatment option. However, tumor heterogeneity, differences in the immune conditions of patients, and the interrelation between tumor cells and stromal cells within the tumor microenvironment (TME) could affect the therapeutic efficacy of immune checkpoint blockades. Therefore, to maximize the benefit of blockade PD-1/PD-L1 axis, to find an efficient predictor (the possible clinical parameters or biological factors) before treatment are of great importance. In this review, we discuss the advantages of anti-PD-1/PD-L1 therapy for OSCC patients and find three respects that are currently available in predicting curative effect. Firstly, OSCC with high PD-L1 expression evaluating by immunohistochemistry (high tumor proportion score (TPS) and combined positive score (CPS)) are considered to be suitable for anti-PD-1/PD-L1 therapy. Secondly, gene-level predictive biomarkers including high metastatic mismatch repair deficiency (dMMR) signature or enrichment of interferon-γ and PD1 signaling pathway is expected to be favorable factors. Besides, PET/CT parameters (SUV_max, MTV, TLG) are proved to be correlated with PD-L1 expression, and some newly developed immunoPET probes are enlarging the application of PET/CT in predicting therapeutic efficacy of PD-1/PD-L1 inhibitors.

Sex determining region Y-box 9 induced microtubule formation and epithelial⁃mesenchymal transition in human oral squamous cell carcinoma CAL27 cells

OBJECTIVES

This study aimed to explore the effect of sex determining region Y-box 9 (SOX9) on the microtubule formation and epithelial-mesenchymal transition (EMT) of human oral squamous cell carcinoma (OSCC) CAL27 and the underlying mechanism.

METHODS

SOX9-shRNA1 and SOX9-shRNA2 were designed and synthesized and then transfected into CAL27 cells. The expression of SOX9 was detected by quantitative real-time polymerase chain reaction. Microtubule formation assay was used to detect the change in the number of microtubule nodules after interfering with SOX9. Immunofluorescence was used to detect the Vimentin content. Western blot was used to detect the protein expression of EMT marker molecules and Wnt/β-catenin pathway-related proteins, such as E-cadherin, N-cadherin, Fibronectin, Wnt, β-catenin, T-cell factor-4 (TCF-4).

RESULTS

The expression level of SOX9 significantly decreased after transfection with SOX9-shRNA1 and SOX9-shRNA2 in CAL27 cells (F=578.000, P=0.000; F=96.850, P=0.000). Interference with SOX9 inhibited the EMT of OSCC. After interference with SOX9, the number of tubules and Vimentin positive cells decreased significantly (F=169.700, P=0.000). The expression level of E-cadherin significantly increased (F=181.400, P=0.000). The expression levels of N-cadherin, Fibronectin, Wnt, β-catenin, and TCF-4 proteins significantly decreased (N-cadherin: F=101.400, P=0.000; Fibronectin: F=122.300, P=0.000; Wnt: F=70.290, P=0.000; β-catenin: F=81.740, P=0.000; TCF-4: F=37.020, P=0.000).

CONCLUSIONS

Interference with SOX9 decreased Vimentin content and inhibited the microtubule formation and protein expression of EMT marker molecules, as well as the expression of proteins related to the Wnt/β-catenin pathway. Thus, SOX9 can induce microtubule formation and EMT in CAL27, which was related to the inhibition of the Wnt/β-catenin pathway activation.

The immunologic tumor microenvironment in endometrioid endometrial cancer in the morphomolecular context: mutual correlations and prognostic impact depending on molecular alterations

OBJECTIVE

POLE-mutant, microsatellite-instable (MSI), p53-mutant and non-specific molecular profile (NSMP) are TCGA-defined molecular subgroups of endometrial cancer (EC). Hypothesizing that morphology and tumor immunology might differ depending on molecular background concerning composition and prognostic impact, we aimed to comprehensively interconnect morphologic, immunologic and molecular data.

METHODS

TCGA-defined molecular groups were determined by immunohistochemistry and sequencing in n = 142 endometrioid EC. WHO-defined histopathological grading was performed. The immunologic microenvironment (iTME) was characterised by the quantification of intraepithelial and stromal populations of tumor-infiltrating lymphocytes (TIL: overall T-cells; T-Killer cells; regulatory T-cells (Treg)). Immunologic parameters were correlated with WHO-grading, TCGA-subgroups and prognosis.

RESULTS

High density TIL were significantly more frequent in high-grade (G3) compared to low-grade (G1/2) EC in the whole cohort and in the subgroup of POLE-wildtype-/microsatellite-stable-EC. MSI was associated with high-level TIL-infiltration when taking into account the type of mismatch repair defect (MLH1/PMS2; MSH2/MSH6). Prognostic impact of biomarkers depended on molecular subgroups: In p53-mutant EC, Treg were independently prognostic, in NSMP, the unique independently prognostic biomarker was WHO-grading.

CONCLUSIONS

EC morphology and immunology differ depending on genetics. Our study delineated two molecularly distinct subgroups of immunogenic EC characterized by high-density TIL-infiltration: MSI EC and high-grade POLE-wildtype/microsatellite-stable-EC. Prognostic impact of TIL-populations relied on TCGA-subgroups indicating specific roles for TIL depending on molecular background. In NSMP, histopathological grading was the only prognostic biomarker demonstrating the relevance of WHO-grading in an era of molecular subtyping.

Genomic landscape and clonal architecture of mouse oral squamous cell carcinomas dictate tumour ecology

To establish whether 4-nitroquinoline N-oxide-induced carcinogenesis mirrors the heterogeneity of human oral squamous cell carcinoma (OSCC), we have performed genomic analysis of mouse tongue lesions. The mutational signatures of human and mouse OSCC overlap extensively. Mutational burden is higher in moderate dysplasias and invasive SCCs than in hyperplasias and mild dysplasias, although mutations in p53, Notch1 and Fat1 occur in early lesions. Laminin-α3 mutations are associated with tumour invasiveness and Notch1 mutant tumours have an increased immune infiltrate. Computational modelling of clonal dynamics indicates that high genetic heterogeneity may be a feature of those mild dysplasias that are likely to progress to more aggressive tumours. These studies provide a foundation for exploring OSCC evolution, heterogeneity and progression.

Prognostic impact of regulatory T cell in head and neck squamous cell carcinoma: A systematic review and meta-analysis

OBJECTIVES

The impact of regulatory T (Treg) cells as a prognostic factor of survival in head and neck squamous cell carcinoma (HNSCC) remains controversial. We aimed to evaluate the prognostic value of Treg cells in patients with HNSCC through a meta-analysis.

MATERIALS AND METHODS

Through a literature search in PubMed, Embase, and Cochrane, we included 11 articles in this meta-analysis and investigated the effect of Treg cell level on the survival of patients with HNSCC. Also, we performed a subgroup analysis according to the study sample (blood vs. tumor tissue), primary tumor site, HPV infectivity, or Treg cell marker.

RESULTS

High levels of circulating Treg cells in the peripheral blood of patients with HNSCC can significantly increase the disease specific survival rate of patients. Moreover, subgroup analysis showed that high levels of Treg in peripheral blood were significantly associated with better disease specific survival in patients with oral cancer, a subsite of HNSCC, but not in those with other head and neck subsite. Positivity of HPV infection did not influence the prognosis of patients with HNSCC.

CONCLUSION

Increase in the levels of circulating Treg cells in peripheral blood can be a prognostic factor of survival in patients with oral cancer.

Prognostic value of HLA class I expression in patients with oral squamous cell carcinoma

Human leukocyte antigen (HLA) class Ⅰ molecules play a central role in anticancer immunity, but their prognostic value in oral squamous cell carcinoma (OSCC) remains unclear. We examined HLA class I expression in 2 distinct tumor compartments, namely, the tumor center and invasive front, and evaluated the association between its expression pattern and histopathological status in 137 cases with OSCC. Human leukocyte antigen class Ⅰ expression was graded semiquantitatively as high, low, and negative. At the invasive front of the tumor, HLA class I expression was high in 72 cases (52.6%), low in 44 cases (32.1%), and negative in 21 cases (15.3%). The HLA class I expression in the tumor center was high in 48 cases (35.0%), low in 58 cases (42.4%), and negative in 31 cases (22.6%). The 5‐year overall survival and disease‐specific survival rates were good in cases with high HLA class I expression at the invasive front; however, there was no significant difference in survival based on HLA class I expression in the tumor center. In addition, high HLA class I expression was correlated with high CD8⁺ T cell density, whereas negative HLA class I expression was correlated with low CD8⁺ T cell density at the invasive front. These results suggest that it is easier for CD8⁺ T cells to recognize presented peptides in the case of high HLA class Ⅰ expression at the tumor invasive front and could be a prognostic factor for OSCC.

Integrin-α5 promoted the progression of oral squamous cell carcinoma and modulated PI3K/AKT signaling pathway

BACKGROUND

Integrin-α5 (ITGA5) gene has been reported to be critical for the progression of several cancers. However, the effects of ITGA5 in oral squamous cell carcinoma (OSCC) remain unclear.

METHODS

We firstly used bioinformatics methods to analyze the ITGA5 gene expression based on the public dataset. HO1-N-1 and SCC-9 cells with silenced ITGA5 were constructed using siRNA. Then, we determined the biological functions of ITGA5 in OSCC cells using cell counting kit-8 (CCK-8) assay, colony formation assay, wound healing assay and transwell assays. The expression of PI3K, p-PI3K, AKT, p-AKT, ERK and pERK were determined by western blot.

RESULTS

Our results revealed that ITGA5 expression was up-regulated in OSCC. The biological experiments further confirmed that ITGA5 expression was higher in OSCC cell lines. Moreover, we found that knockdown of ITGA5 inhibited the proliferation, migration and invasion of OSCC cells. The expression of phosphorylated-(p) PI3K, p-AKT and p-ERK obviously decreased after knockdown of ITGA5 in OSCC cells.

CONCLUSION

In summary, ITGA5 could promote the progression of OSCC via activating the PI3K/AKT signaling pathway, and it can be regarded as a potential biomarker for OSCC treatment.

Tissue-infiltrating immune cells as prognostic markers in oral squamous cell carcinoma: a systematic review and meta-analysis

Background

Various immune cells have been suggested as prognostic markers for cancer patients. In this article, we present a systematic review and meta-analysis of studies assessing the prognostic value of tissue-infiltrating immune cells in oral cancer and discuss the reporting quality of these studies.

Methods

We performed a systematic literature search and included studies using immunohistochemistry and survival analysis to assess the prognostic value of tumour-infiltrating T cells, B cells, macrophages, dendritic cells, mast cells and natural killer cells in oral cancer. We performed meta-analysis of studies providing necessary statistical data and investigated the studies’ adherence to the REporting recommendations for tumour MARKer prognostic studies (REMARK) guidelines.

Results

Of the 1960 articles identified, 33 were eligible for this systematic review and 8 were included in the meta-analysis. CD163+ M2 macrophages and CD57+ natural killer cells were the most promising predictors of survival in oral cancer patients. Many studies lacked important information on their design and conduct.

Conclusion

Deficiencies in the reporting of study design and conduct make it difficult to draw reliable conclusions about the suggested markers. The prognostic value of CD163+ M2 macrophages and CD57+ natural killer cells should be validated in large, standardised studies.

Composition and Clinical Impact of the Immunologic Tumor Microenvironment in Oral Squamous Cell Carcinoma

Immunotherapy shows promising results and revolutionizes treatment of oral squamous cell carcinoma (OSCC). The immunologic microenvironment might have prognostic/predictive implications. Morphologic immunologic parameters (inflammatory infiltrate, stromal content, and budding activity [BA] [potentially indicating epithelial-mesenchymal transition]) were evaluated in 66 human primary therapy-naive OSCCs. Intraepithelial/stromal tumor-infiltrating lymphocytes (TILs; CD3⁺/CD4⁺/CD8⁺/CD4⁺FOXP3⁺/IL-17A⁺) were quantified, and ratios were calculated. HLA class I in tumor cells was evaluated immunohistochemically. mRNA in situ hybridization to detect IFN-γ was performed. Analysis was performed within invasive front (IF) and tumor center (TCe). Decreased HLA expression was associated with low TIL density, pronounced stromal content, and high BA; IFN-γ in TILs was correlated with high-density TILs; and IFN-γ in tumor cells was correlated with absence of BA (p < 0.05). Heterogeneity of parameters (TCe/IF) was rare. Low density of stromal CD4⁺FOXP3⁺ TILs within TCe and IF was identified as an independent prognostic factor for poor overall, disease-specific, and disease-free survival (p ≤ 0.011). Refining prognostication in OSCC with high-density CD4⁺FOXP3⁺ infiltrate within TCe and/or IF, high FOXP3:CD4 ratio was significantly correlated with favorable outcome in this subgroup. Furthermore, high-stromal CD8:CD4 ratio was found to be an independent favorable prognostic factor. In summary, immunologic parameters were closely intertwined. Morphologic correlates of epithelial-mesenchymal transition were associated with downregulation of HLA and decreased inflammation. Heterogeneity was infrequent. Low-density stromal CD4⁺FOXP3⁺ infiltrate within TCe and IF was an independent poor prognostic factor. Stratification of cases with high-density CD4⁺FOXP3⁺ TILs by FOXP3:CD4 ratio enables refinement of prognostication of this subgroup. CD8:CD4 ratio was identified as an independent prognostic factor.

Immunomodulatory role of Keratin 76 in oral and gastric cancer

Keratin 76 (Krt76) is expressed in the differentiated epithelial layers of skin, oral cavity and squamous stomach. Krt76 downregulation in human oral squamous cell carcinomas (OSCC) correlates with poor prognosis. We show that genetic ablation of Krt76 in mice leads to spleen and lymph node enlargement, an increase in regulatory T cells (Tregs) and high levels of pro-inflammatory cytokines. Krt76^-/- Tregs have increased suppressive ability correlated with increased CD39 and CD73 expression, while their effector T cells are less proliferative than controls. Loss of Krt76 increases carcinogen-induced tumours in tongue and squamous stomach. Carcinogenesis is further increased when Treg levels are elevated experimentally. The carcinogenesis response includes upregulation of pro-inflammatory cytokines and enhanced accumulation of Tregs in the tumour microenvironment. Tregs also accumulate in human OSCC exhibiting Krt76 loss. Our study highlights the role of epithelial cells in modulating carcinogenesis via communication with cells of the immune system.

Differentiated State of Initiating Tumor Cells Is Key to Distinctive Immune Responses Seen in H-RasG12V-Induced Squamous Tumors

Heterogeneity in tumor immune responses is a poorly understood yet critical parameter for successful immunotherapy. In two doxycycline-inducible models where oncogenic H-Ras^G12V is targeted either to the epidermal basal/stem cell layer with a Keratin14-rtTA transgene (K14Ras), or committed progenitor/suprabasal cells with an Involucrin-tTA transgene (InvRas), we observed strikingly distinct tumor immune responses. On threshold doxycycline levels yielding similar Ras expression, tumor latency, and numbers, tumors from K14Ras mice had an immunosuppressed microenvironment, whereas InvRas tumors had a proinflammatory microenvironment. On a Rag1^-/- background, InvRas mice developed fewer and smaller tumors that regressed over time, whereas K14Ras mice developed more tumors with shorter latency than Rag1^+/+ controls. Adoptive transfer and depletion studies revealed that B-cell and CD4 T-cell cooperation was critical for tumor yield, lymphocyte polarization, and tumor immune phenotype in Rag1^+/+ mice of both models. Coculture of tumor-conditioned B cells with CD4 T cells implicated direct contact for Th1 and regulatory T cell (Treg) polarization, and CD40-CD40L for Th1, Th2, and Treg generation, a response not observed from splenic B cells. Anti-CD40L caused regression of InvRas tumors but enhanced growth in K14Ras, whereas a CD40 agonist mAb had opposite effects in each tumor model. These data show that position of tumor-initiating cells within a stratified squamous epithelial tissue provokes distinct B- and CD4 T-cell interactions, which establish unique tumor microenvironments that regulate tumor development and response to immunotherapy. Cancer Immunol Res; 5(3); 198-210. ©2017 AACR.