Stroma modulation of radiation response in head and neck squamous cell carcinoma: Insights from zebrafish larvae xenografts

BACKGROUND

The tumour microenvironment (TME) of head and neck squamous cell carcinoma (HNSCC) consists of different subtypes of cells that interact with the tumour or with each other. This study investigates the possibility of co-culturing HNSCC cells with different stroma cells in a zebrafish xenograft model, focusing on the effect of stroma cells on HNSCC growth and response to irradiation.

MATERIAL AND METHOD

HNSCC metastatic cell line HSC-3 was used along with five types of stroma cells: normal gingival fibroblasts (NOF), cancer associated fibroblasts (CAF), macrophages, CD4+ T cells, and human umbilical vein endothelial cells (HUVEC). The mixture of HSC-3 cells and each-stroma cell type-was injected into 2-day post-fertilization zebrafish embryos, and the effect of stroma cells on tumour growth was tested. The study also aimed to mimic the HNSCC tumour by injecting a mixture of HSC-3 cells, CAFs, macrophages, and HUVECs into zebrafish embryos and testing the effect of these stroma cells on the cancer cells' response to irradiation compared to HSC-3-only tumours.

RESULTS

CAFs had a significant inducement effect on tumour size, while HUVECs showed the opposite effect. The irradiated group of HSC-3-only tumour had a significantly smaller tumor cell area compared to the control, while the group with stroma cells and HSC-3 cells showed cancer cells being resistant to irradiation.

CONCLUSION

This is the first report of co-culturing cancer cells with several types of stroma cells using a zebrafish xenograft model. This study also highlighted the role of stroma cells in turning the cancer cells from radioresponsive to radioresistant.

Novel human lymph node-derived matrix supports the adhesion of metastatic oral carcinoma cells

BACKGROUND

3D culture is increasingly used in cancer research, as it allows the growth of cells in an environment that mimics in vivo conditions. Metastases are the primary cause of morbidity and mortality in cancer patients, and solid tumour metastases are mostly located in lymph nodes. Currently, there are no techniques that model the pre-metastatic lymph node microenvironment in vitro. In this study, we prepared a novel extracellular matrix, Lymphogel, which is derived from lymph nodes, mimicking the tumour microenvironment (TME) of metastatic carcinoma cells. We tested the suitability of the new matrix in various functional experiments and compared the results with those obtained using existing matrices.

METHODS

We used both commercial and patient-derived primary and metastatic oral tongue squamous cell carcinoma (OTSCC) cell lines. We characterized the functional differences of these cells using three different matrices (human uterine leiomyoma-derived Myogel, human pre-metastatic neck lymph node-derived Lymphogel (h-LG), porcine normal neck lymph node-derived Lymphogel (p-LG) in proliferation, adhesion, migration and invasion assays. We also performed proteomic analyses to compare the different matrices in relation to their functional properties.

RESULTS

OTSCC cells exhibited different adhesion and invasion patterns depending on the matrix. Metastatic cell lines showed improved ability to adhere to h-LG, but the effects of the matrices on cell invasion fluctuated non-significantly between the cell lines. Proteomic analyses showed that the protein composition between matrices was highly variable; Myogel contained 618, p-LG 1823 and h-LG 1520 different proteins. The comparison of all three matrices revealed only 120 common proteins. Analysis of cellular pathways and processes associated with proteomes of each matrix revealed similarities of Myogel with h-LG but less with p-LG. Similarly, p-LG contained the least adhesion-related proteins compared with Myogel and h-LG. The highest number of unique adhesion-related proteins was present in h-LG.

CONCLUSIONS

We demonstrated that human pre-metastatic neck lymph node-derived matrix is suitable for studying metastatic OTSCC cells. As a whole-protein extract, h-LG provides new opportunities for in vitro carcinoma cell culture experiments.

The effect of matrices on the gene expression profile of patient-derived head and neck carcinoma cells for in vitro therapy testing

OBJECTIVE

Head and neck squamous cell carcinoma (HNSCC) is a highly aggressive tumor with a 5-year mortality rate of ~ 50%. New in vitro methods are needed for testing patients' cancer cell response to anti-cancer treatments. We aimed to investigate how the gene expression of fresh carcinoma tissue samples and freshly digested single cancer cells change after short-term cell culturing on plastic, Matrigel or Myogel. Additionally, we studied the effect of these changes on the cancer cells' response to anti-cancer treatments.

MATERIALS/METHODS

Fresh tissue samples from HNSCC patients were obtained perioperatively and single cells were enzymatically isolated and cultured on either plastic, Matrigel or Myogel. We treated the cultured cells with cisplatin, cetuximab, and irradiation; and performed cell viability measurement. RNA was isolated from fresh tissue samples, freshly isolated single cells and cultured cells, and RNA sequencing transcriptome profiling and gene set enrichment analysis were performed.

RESULTS

Cancer cells obtained from fresh tissue samples changed their gene expression regardless of the culturing conditions, which may be due to the enzymatic digestion of the tissue. Myogel was more effective than Matrigel at supporting the upregulation of pathways related to cancer cell proliferation and invasion. The impacts of anti-cancer treatments varied between culturing conditions.

CONCLUSIONS

Our study showed the challenge of in vitro cancer drug testing using enzymatic cell digestion. The upregulation of many targeted pathways in the cultured cells may partially explain the common clinical failure of the targeted cancer drugs that pass the in vitro testing.

Detection of herpes simplex virus in oral tongue squamous cell carcinoma

Introduction: Oral tongue squamous cell carcinoma (OTSCC) is the most common cancer of the oral cavity. Contradictory results have been observed on the involvement of herpes simplex virus 1 (HSV-1) in oral squamous cell carcinomas. Here, we aimed to study the predominance of HSV-1 or HSV-2 in oral HSV infections and to investigate the presence of HSV-1 in OTSCC and its effect on carcinoma cell viability and invasion. Methods: The distribution of HSV types one and two in diagnostic samples taken from suspected oral HSV infections was determined from the Helsinki University Hospital Laboratory database. We then analysed 67 OTSCC samples for HSV-1 infection using immunohistochemical staining. We further tested the effects of HSV-1 using six concentrations (0.00001-1.0 multiplicity of infection [MOI]) on viability and two concentrations (0.001 and 0.1 MOI) on invasion of highly invasive metastatic HSC-3 and less invasive primary SCC-25 OTSCC cell lines using MTT and Myogel-coated Transwell invasion assays. Results: Altogether 321 oropharyngeal samples were diagnosed positive for HSV during the study period. HSV-1 was the predominant (97.8%) HSV type compared with HSV-2 (detected in 2.2% of samples). HSV-1 was also detected in 24% of the OTSCC samples and had no association with patient survival or recurrence. OTSCC cells were viable even after 6 days with low viral load (0.00001, 0.0001, 0.001 MOI) of HSV-1. In both cell lines, 0.001 MOI did not affect cell invasion. However, 0.1 MOI significantly reduced cell invasion in HSC-3 cells. Discussion: HSV-1 infection is predominant compared with HSV-2 in the oral cavity. HSV-1 is detected in OTSCC samples without clinical significance, and OTSCC cell survival or invasion was not affected at low doses of HSV-1.

Evaluation of in vitro and in vivo personalized cancer treatment assays for oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a common cancer with a high heterogeneity and few approved treatments. OSCC is one of the least explored areas for precision oncology. In this study, we aimed to test the reliability of our three established rapid cancer systemic treatment-testing assays: human tumour-derived matrix (Myogel)-coated well-plates, zebrafish xenografts, and 3D microfluidic chips.

METHODS

Chemo-, radio- and targeted-therapy testing in Myogel-coated wells and zebrafish xenografts was conducted nine times using five samples; two primary and three metastatic lymph node samples from three OSCC patients. Peripheral blood mononuclear cells (PBMNCs) were isolated from the patients' blood. The response of the tumour cells to radio-, chemo-, and targeted therapy was tested using Myogel-coated wells and zebrafish larvae xenografts. The tumour cells' response to immunotherapy was tested using 3D microfluidic chips. The cells' sensitivity to the treatments was compared with the patients' clinical response. Primary and metastatic lymph node tissue-derived DNA samples from two patients underwent whole exome sequencing to compare the mutational profiles of the samples.

RESULTS

Test results were in line with patients' responses in 7/9 (77%) zebrafish xenograft assays and 5/9 (55%) Myogel-coated wells assays. Immunotherapy testing was done using one metastatic patient sample which matched the patients' response. Differences in responses to treatments between primary and metastatic samples of the same patient were detected in 50% of the zebrafish larvae assays.

CONCLUSIONS

Our results show the potential of using personalized cancer treatment testing assays - specifically zebrafish xenografts that revealed promising results - in OSCC patient samples.

Prognostic histological markers in oral tongue squamous cell carcinoma patients treated with (chemo)radiotherapy

Treatment of oral tongue squamous cell carcinoma (OTSCC) frequently includes surgery with postoperative radiotherapy (RT) or chemoradiotherapy (CRT). Resistance to RT or CRT remains a major clinical challenge and highlights the need to identify predictive markers for it. We included 71 OTSCC patients treated with surgery combined with RT or CRT. We evaluated the association between tumor budding, tumor-stroma ratio (TSR), depth of invasion (DOI), tumor-infiltrating lymphocytes (TILs), hypoxia-inducible factor-1alpha (HIF-1alpha) expression, octamer-binding transcription factor 4 (OCT4) expression, high-endothelial venules (HEVs), and disease-free survival (DFS) using uni- and multivariate analyses. No significant association was observed between the different histological and molecular markers (TSR, DOI, TILs, HEV, HIF-1alph, OCT4) and DFS. However, an associative trend between DOI, budding, and DFS was noted. Further studies with larger cohorts are needed to explore the prognostic value of DOI and budding for OTSCC patients treated with postoperative RT or CRT.

Prognostic markers for oral cancer: An overview of the current status and directions for future research

In the last decades, the search for biomarkers for response to therapy and prognosis, with potential of providing information about the likely course and outcome of disease, has been intense in oral squamous cell carcinomas. Although several biomarkers, ranging from genetic and molecular alterations to clinical and histopathological features, have been described, only a few of them are used in routine practice. The aim of this review is to outline the recent advances in oral squamous cell carcinomas biomarkers, exploring those related to clinical and histopathological features, cancer cells and components of the tumor microenvironment. Future directions, highlighting the main issues that limit the clinical application of many of the potential biomarkers, are discussed.

Amphipathic barbiturates as marine product mimics with cytolytic and immunogenic effects on head and neck squamous cell carcinoma cell lines

The incidence of head and neck squamous cell carcinoma (HNSCC) is increasing and the conventional treatments for this form of cancer can be tough. Despite the success of existing immunotherapies in some HNSCC patients, many do not respond to this type of treatment. Thus, the development of novel anti-cancer therapies should be prioritized. In the current study, the anticancer activity of a panel of novel compounds, herein termed marine product mimics (MPMs), against HNSCC cell lines is explored. The previously reported compound MPM-1, which is structurally related to the novel MPMs, was shown to have promising effects on the HNSCC cell line HSC-3. The results from the current study indicate that the novel MPMs are more potent than MPM-1 but cause a similar type of cell death. The results indicated that the MPMs must cross through the cell membrane to exert their action and that they are lysosomotropic. Further experiments showed that some of the MPMs could induce phosphorylation of eukaryotic initiation factor 2α (eIF2α) in HSC-3 and UT-SCC-24A cells, which indicates that they can activate the integrated stress response that is strongly associated with immunogenic cell death. Cell surface expression of calreticulin and release of HMGB1 and ATP, which are all hallmarks of immunogenic cell death, was also demonstrated in HSC-3 and UT-SCC-24A cells treated with MPMs. This suggests that the MPMs are interesting candidates for future HNSCC cancer therapies.

In vitro models as tools for screening treatment options of head and neck cancer

Various in vitro models using primary and established 2- and 3-dimensional cultures, multicellular tumor spheroids, standardized tumor slice cultures, tumor organoids, and microfluidic systems obtained from tumor lesions/biopsies of head and neck cancer (HNC) have been employed for exploring and monitoring treatment options. All of these in vitro models are to a different degree able to capture the diversity of tumors, recapitulate the disease genetically, histologically, and functionally and retain their tumorigenic potential upon xenotransplantation. The models were used for the characterization of the malignant features of the tumors and for in vitro screens of drugs approved for the treatment of HNC, including chemotherapy and radiotherapy as well as recently developed targeted therapies and immunotherapies, or for novel treatments not yet licensed for these tumor entities. The implementation of the best suitable model will enlarge our knowledge of the oncogenic properties of HNC, expand the drug repertoire and help to develop individually tailored treatment strategies resulting in the translation of these findings into the clinic. This review summarizes the different approaches using preclinical in vitro systems with their advantages and disadvantages and their implementation as preclinical platforms to predict disease course, evaluate biomarkers and test therapy efficacy.

Transcriptomic Profiling of JEG-3 cells using human leiomyoma derived matrix

Oxygen tension varies during placental and fetal development. Although hypoxia drives early trophoblast invasion, low placental oxygen levels during pregnancy show association with pregnancy complications including fetal growth restriction and preeclampsia. JEG-3 cells are often used as a trophoblast model. We studied transcriptional changes of JEG-3 cells on a uterine leiomyoma derived matrix Myogel. This might be the closest condition to the real uterine environment that we can get for an in vitro model. We observed that culturing JEG-3 cells on the leiomyoma matrix leads to strong stimulation of ribosomal pathways, energy metabolism, and ATP production. Furthermore, Myogel improved JEG-3 cell adherence in comparison to tissue culture treated plastic. We also included PDMS microchip hypoxia creation, and observed changes in oxidative phosphorylation, oxygen related genes and several hypoxia genes. Our study highlights the effects of Myogel matrix on growing JEG-3 cells, especially on mitochondria, energy metabolism, and protein synthesis.

IDO1 Inhibition Reduces Immune Cell Exclusion Through Inducing Cell Migration While PD-1 Blockage Increases IL-6 and -8 Secretion From T Cells in Head and Neck Cancer

Background

Immune checkpoint inhibitors (ICIs), primarily anti-PD-1, are currently used to treat patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC). However, only a minority of patients benefit from these costly therapies. Therefore, there is an unmet need to better understand the effect of ICIs on immune effector cells. This study aimed to investigate the effect of a PD-1 antibody and an IDO1 inhibitor on different lymphocyte populations (NK, CD4+, and CD8+ T cells) in term of migration, cytotoxicity, and cytokine release in the presence of HNSCC cells.

Methods

Using a microfluidic chip, we injected HSC-3 cells (an oral tongue squamous cell carcinoma cell line) embedded in a human tumor-derived matrix “myogel/fibrin” together with NK, CD4+, and CD8+ T cells in separate channels. The two channels were connected with microchannels. The PD-1 antibody nivolumab and IDO1 inhibitor epacadostat were added to the microfluidic chips. Lymphocyte migration and cytotoxicity were examined under fluorescent microscopy and cytokine release was measured using a FirePlex Human Discovery Cytokines Immunoassay.

Results

Epacadostat significantly increased the migration and infiltration of NK and CD4+ T cells, but not CD8+ T cells, towards the cancer cells. Nivolumab did not exhibit a similar effect. While CD8+ T cells alone showed near to no migration, adding CD4+ T cells enhanced migration towards the cancer cells. There was a mild nonsignificant increase in apoptosis of HSC-3 cells after adding epacadostat to lymphocytes. In contrast, HSC-3 proliferation was not affected by lymphocytes regardless of ICIs. Nivolumab significantly increased release of MIP1-α, IL-6, and IL-8 from NK, CD4+, and CD8+ T cells, respectively.

Conclusions

This study revealed that each subpopulation of lymphocytes respond differently to ICIs. We also revealed the subpopulation of lymphocytes responsible for the increases in specific serum cytokines after ICI treatment.

miR-22 and miR-205 Drive Tumor Aggressiveness of Mucoepidermoid Carcinomas of Salivary Glands

Objectives

To integrate mRNA and miRNA expression profiles of mucoepidermoid carcinomas (MECs) and normal salivary gland (NSGs) tissue samples and identify potential drivers.

Material and Methods

Gene and miRNA expression arrays were performed in 35 MECs and six NSGs.

Results

We found 46 differentially expressed (DE) miRNAs and 3,162 DE mRNAs. Supervised hierarchical clustering analysis of the DE transcripts revealed two clusters in both miRNA and mRNA profiles, which distinguished MEC from NSG samples. The integrative miRNA-mRNA analysis revealed a network comprising 696 negatively correlated interactions (44 miRNAs and 444 mRNAs) involving cell signaling, cell cycle, and cancer-related pathways. Increased expression levels of miR-205-5p and miR-224-5p and decreased expression levels of miR-139-3p, miR-145-3p, miR-148a-3p, miR-186-5p, miR-338-3p, miR-363-3p, and miR-4324 were significantly related to worse overall survival in MEC patients. Two overexpressed miRNAs in MEC (miR-22 and miR-205) were selected for inhibition by the CRISPR-Cas9 method. Cell viability, migration, and invasion assays were performed using an intermediate grade MEC cell line. Knockout of miR-205 reduced cell viability and enhanced ZEB2 expression, while miR-22 knockout reduced cell migration and invasion and enhanced ESR1 expression. Our results indicate a distinct transcriptomic profile of MEC compared to NSG, and the integrative analysis highlighted miRNA-mRNA interactions involving cancer-related pathways, including PTEN and PI3K/AKT.

Conclusion

The in vitro functional studies revealed that miR-22 and miR-205 deficiencies reduced the viability, migration, and invasion of the MEC cells suggesting they are potential oncogenic drivers in MEC.

Variable roles of interleukin-17F in different cancers

BACKGROUND

Interleukin (IL)-17 family is a group of six cytokines that plays a central role in inflammatory processes and participates in cancer progression. Interleukin-17A has been shown to have mainly a protumorigenic role, but the other members of the IL-17 family, including IL-17F, have received less attention.

METHODS

We applied systematic review guidelines to study the role of IL-17F, protein and mRNA expression, polymorphisms, and functions, in cancer. We carried out a systematic search in PubMed, Ovid Medline, Scopus, and Cochrane libraries, yielding 79 articles that met the inclusion criteria.

RESULTS

The findings indicated that IL-17F has both anti- and protumorigenic roles, which depend on cancer type and the molecular form and location of IL-17F. As an example, the presence of IL-17F protein in tumor tissue and patient serum has a protective role in oral and pancreatic cancers, whereas it is protumorigenic in prostate and bladder cancers. These effects are proposed to be based on multiple mechanisms, such as inhibition of angiogenesis, vasculogenic mimicry and cancer cell proliferation, migration and invasion, and aggravating the inflammatory process. No solid evidence emerged for the correlation between IL-17F polymorphisms and cancer incidence or patients' prognosis.

CONCLUSION

IL-17F is a multifaceted cytokine. There is a clear demand for more well-designed studies of IL-17F to elucidate its molecular mechanisms in different types of cancer. The studies presented in this article examined a variety of different designs, study populations and primary/secondary outcomes, which unfortunately reduces the value of direct interstudy comparisons.

The expression and prognostic relevance of CDH3 in tongue squamous cell carcinoma

P-cadherin (CDH3) is a cell-to-cell adhesion molecule that regulates several cellular homeostatic processes in normal tissues. Lack of CDH3 expression is associated with aggressive behavior in oral squamous cell carcinoma (OSCC). Previous studies have shown that CDH3 is downregulated in high-grade OSCC and its reduced expression is predictive for poorer survival. The aim of this study was to evaluate the expression and prognostic relevance of CDH3 in tongue squamous cell carcinoma (TSCC). A retrospective series of 211 TSCC and 50 lymph node samples were stained immunohistochemically with polyclonal antibody (anti-CDH3). CDH3 expression was assessed semi-quantitatively with light microscopy. Fisher's exact test was used to compare patient and tumor characteristics, and the correlations were tested by Spearman correlation. Survival curves were drawn by the Kaplan-Meier method and analyzed by the log-rank test. Univariate and multivariate Cox regression was used to estimate the association between CDH3 expression and survival. CDH3 expression did not affect TSCC patient's disease-specific survival or overall survival. Strong CDH3 expression in the primary tumor predicted poor disease-specific and overall survival in patients with recurrent disease. CDH3 expression in lymph nodes without metastasis was negative in all cases. CDH3 expression was positive in all lymph node metastases with extranodal extension. In contrast to previous report about the prognostic value of CDH3 in OSCC, we were not able to validate the result in TSCC.

The effect of fascin 1 inhibition on head and neck squamous cell carcinoma cells

Fascin 1 plays important pro-metastatic roles in head and neck carcinoma (HNSCC) migration, invasion, and metastasis. However, limited advancement in targeting metastasis remains a major obstacle in improving HNSCC patients' survival. Therefore, we assessed the therapeutic potential of fascin 1 targeted inhibition and its potential prognostic value in HNSCC patients. Using in vitro and in vivo approaches, we investigated the effect of compound G2, a novel fascin 1 inhibitor, on HNSCC cells migration, invasion, and metastasis. High-throughput screening (HTS) was used to assess cytotoxic activity of compound G2 alone or combined with irradiation. We also evaluated the prognostic potential of fascin 1 in HNSCC patients. Interestingly, compound G2 reduced carcinoma cells migration and invasion in vitro and inhibited metastasis in vivo. Moreover, HTS revealed a modest cytotoxic activity of the compound G2 on HNSCC cell lines. Irradiation did not synergistically enhance the compound G2-mediated cytotoxic activity. Survival analyses showed that high fascin 1 immunoexpression, at the tumor invasive front, was associated with cancer-specific mortality in the advanced stages of HNSCC. Collectively, our findings suggest that fascin 1 represents a promising anti-metastatic therapeutic target and a useful prognostic marker in patients with HNSCC. Novel anti-metastatic agents could provide a valuable addition to cancer therapy.

Angiogenesis Inhibitors for Head and Neck Squamous Cell Carcinoma Treatment: Is There Still Hope?

Background

Head and neck squamous cell carcinoma (HNSCC) carries poor survival outcomes despite recent progress in cancer treatment in general. Angiogenesis is crucial for tumour survival and progression. Therefore, several agents targeting the pathways that mediate angiogenesis have been developed. We conducted a systematic review to summarise the current clinical trial data examining angiogenesis inhibitors in HNSCC.

Methods

We carried out a literature search on three angiogenesis inhibitor categories—bevacizumab, tyrosine kinase inhibitors and endostatin—from Ovid MEDLINE, Cochrane Library, Scopus and ClinicalTrials.gov database.

Results

Here, we analysed 38 clinical trials, total of 1670 patients, investigating 12 angiogenesis inhibitors. All trials were in phase I or II, except one study in phase III on bevacizumab. Angiogenesis inhibitors were used as mono- and combination therapies together with radio-, chemo-, targeted- or immunotherapy. Among 12 angiogenesis inhibitors, bevacizumab was the most studied drug, included in 13 trials. Although bevacizumab appeared effective in various combinations, it associated with high toxicity levels. Endostatin and lenvatinib were well-tolerated and their anticancer effects appeared promising.

Conclusions

Most studies did not show benefit of angiogenesis inhibitors in HNSCC treatment. Additionally, angiogenesis inhibitors were associated with considerable toxicity. However, some results appear encouraging, suggesting that further investigations of angiogenesis inhibitors, particularly in combination therapies, for HNSCC patients are warranted.

Systematic Review Registration

PROSPERO (https://www.crd.york.ac.uk/prospero/), identifier CRD42020157144.

The effect of interleukin-17F on vasculogenic mimicry in oral tongue squamous cell carcinoma

Oral tongue squamous cell carcinoma (OTSCC) is one of the most common cancers worldwide and is characterized by early metastasis and poor prognosis. Recently, we reported that extracellular interleukin-17F (IL-17F) correlates with better disease-specific survival in OTSCC patients and has promising anticancer effects in vitro. Vasculogenic mimicry (VM) is the formation of an alternative vasculogenic system by aggressive tumor cells, which is implicated in treatment failure and poor survival of cancer patients. We sought to confirm the formation of VM in OTSCC and to investigate the effect of IL-17F on VM formation. Here, we showed that highly invasive OTSCC cells (HSC-3 and SAS) form tube-like VM on Matrigel similar to those formed by human umbilical vein endothelial cells. Interestingly, the less invasive cells (SCC-25) did not form any VM structures. Droplet-digital PCR, FACS, and immunofluorescence staining revealed the presence of CD31 mRNA and protein in OTSCC cells. Additionally, in a mouse orthotopic model, HSC-3 cells expressed VE-cadherin (CD144) but lacked Von Willebrand Factor. We identified different patterns of VM structures in patient samples and in an orthotopic OTSCC mouse model. Similar to the effect produced by the antiangiogenic drug sorafenib, IL-17F inhibited the formation of VM structures in vitro by HSC-3 and reduced almost all VM-related parameters. In conclusion, our findings indicate the presence of VM in OTSCC and the antitumorigenic effect of IL-17F through its effect on the VM. Therefore, targeting IL-17F or its regulatory pathways may lead to promising therapeutic strategies in patients with OTSCC.

Effect of Sex Steroid Hormones on Tongue Cancer Cells In Vitro

BACKGROUND

Tongue cancer is more common in men than in women. Yet the effects of sex steroid hormones on the behaviour of oral tongue squamous cell carcinoma (OTSCC) are not well known. Matrix metalloproteinase 8 (MMP8) is expressed in OTSCC and can degrade estrogen receptors (ERs).

MATERIALS AND METHODS

Western blot was used to examine the levels of ERβ in OTSCC cell lines (HSC-3 and SCC-25). We evaluated the effects of estradiol and dihydrotestosterone (DHT) on HSC-3 and SCC-25 cell migration, invasion and viability. The effect of estradiol on the invasion of MMP8-overexpressing (MMP8⁺) and empty vector HSC-3 cells was examined using 3D spheroid invasion assay.

RESULTS

Both HSC-3 and SCC-25 cells expressed ERβ. In scratch assay, estradiol, but not DHT, reduced the migration and invasion of HSC-3 and SCC-25 cells. MMP8⁺ HSC-3 cells showed weaker invasion than empty vector cells, in line with previous reports. However, MMP8 overexpression did not alter the effect of estradiol on HSC-3 cell invasion in spheroid assay.

CONCLUSION

Estradiol inhibited the migration and invasion of OTSCC cells, whereas DHT had no effect. Our data suggest that MMP8 does not modulate the effect of estradiol in OTSCC cells. However, the sex difference in OTSCC incidence might partly be due to protective actions of estradiol in epithelial cell carcinogenesis.

The expression and prognostic relevance of programmed cell death protein 1 in tongue squamous cell carcinoma

Programmed cell death protein 1 (PD-1) is an immune checkpoint receptor which plays an important role in a patient's immune responses to microbial and cancer antigens. It is expressed in tumor-infiltrating lymphocytes (TILs) with many different malignancies. The aim of the study was to evaluate PD-1 expression and its prognostic value in tongue cancer. The data of tongue squamous cell carcinoma (TSCC) patients (N = 81) treated in Tampere University Hospital between 1999 and 2013 were used. Control data consisted of patients with non-malignant tongue mucous membrane lesions (N = 48). The formalin-fixed paraffin-embedded samples were stained immunohistochemically and scanned via digital microscope. The staining of PD-1 was examined semi-quantitatively. The density and intensity of PD-1 + cells were significantly higher in TSCC than in control samples. The expression of PD-1 correlated with better survival. The expression of PD-1 could be a potential prognostic marker in TSCC. Further research using larger sample size is needed.

Evaluation Challenges in the Validation of B7-H3 as Oral Tongue Cancer Prognosticator

B7-H3 was the only molecule identified with prognostic potential from a recent systematic review of the prognostic value of immune checkpoints in oral cancer. We aimed to validate this finding in a multicenter international cohort. We retrospectively retrieved 323 oral tongue squamous cell carcinoma (OTSCC) samples from three different countries (Brazil, Finland, and Norway) for immunostaining and scoring for B7-H3. We evaluated tumor immunogenicity by analyzing the amount of tumor-infiltrating lymphocytes and divided the tumors into immune hot and cold. To increase the reliability of the results, both digital and manual visual scoring were used. Survival curves were constructed based on the Kaplan-Meier method, and the Cox proportional hazard model was utilized for univariate and multivariate survival analysis. B7-H3 expression was not significantly associated with overall or disease-specific survival in the whole OTSCC cohort. When divided into immune hot and cold tumors, high B7-H3 expression was significantly associated with poor disease-specific and overall survival in the immune hot group, depending on the scoring method and the country of the cohort. This was achieved only in the univariate analysis. In conclusion, B7-H3 was a negative prognosticator for OTSCC patient survival in the subgroup of immune hot tumors, and was not validated as a prognosticator in the full cohort. Our findings suggest that the immune activity of the tumor should be considered when testing immune checkpoints as biomarkers.

Human myoma tissue-based extracellular matrix models for testing the effects of irradiation on the HPV positive cells

Background

This study was designed to investigate the invasion of human papillomavirus (HPV) positive human cervical carcinoma cell lines in human leiomyoma-based extracellular matrices in vitro, and to test the suitability of the model for studying the irradiation effects on the cancer cell invasion.

Methods

HPV positive cervical carcinoma cell lines SiHa and CaSki, and HPV negative squamous cell carcinoma cell line HSC-3 were used. CaSki cells contain around 600 copies of HPV 16 virus in the genome, whereas SiHa have only 1–2 copies per cell. Cells were analyzed using two different human tumor derived extracellular matrix methods (3D myoma disc model, and Myogel Transwell invasion assay). Cultures were irradiated with 4 Gy. Myoma invasion area and the depth of invasion were measured with ImageJ 1.51j8 software. Statistical analyses were performed with SPSS Statistics (IBM SPSS® Statistics 25).

Results

All cells invaded through Myogel coated Transwell membranes and within myoma discs. In myoma discs, a difference in the invasion depth (p = 0.0001) but not in invasion area (p = 0.310) between the HPV positive cell lines was seen, since SiHa (less HPV) invaded slightly better than CaSki (more HPV). HSC-3 cells (HPV negative) invaded deepest (p = 0.048) than either of the HPV positive cell line cells. No difference was detected in the invasion area (p = 0.892) between HPV positive and HPV negative cells. The ionized radiation significantly reduced the invasion depth of HSC-3 (p = 0.008), SiHa (p = 0.0001) and CaSki (p = 0.005). No significant effect on the invasion area was detected in any of the cell lines. However, a significant difference was observed between SiHa and CaSki in the reduction of the invasion depth after radiation (p = 0.013) as the reduction was greater with SiHa than CaSki.

Conclusions

Both solid and gelatinous human leiomyoma-based extracellular matrix models were suitable platforms to study the invasion of HPV positive cervical carcinoma cells in vitro. SiHa cells with less HPV copy number cells invaded slightly better and were slightly more sensitive to irradiation than CaSki cells with high HPV copy number. However, there was no drastic differences between the invasion properties of these carcinoma cells.

Human Tumor-Derived Matrix Improves the Predictability of Head and Neck Cancer Drug Testing

In vitro cancer drug testing carries a low predictive value. We developed the human leiomyoma–derived matrix “Myogel” to better mimic the human tumor microenvironment (TME). We hypothesized that Myogel could provide an appropriate microenvironment for cancer cells, thereby allowing more in vivo–relevant drug testing. We screened 19 anticancer compounds, targeting the epidermal growth factor receptor (EGFR), MEK, and PI3K/mTOR on 12 head and neck squamous cell carcinoma (HNSCC) cell lines cultured on plastic, mouse sarcoma–derived Matrigel (MSDM), and Myogel. We applied a high-throughput drug screening assay under five different culturing conditions: cells in two-dimensional (2D) plastic wells and on top or embedded in Matrigel or Myogel. We then compared the efficacy of the anticancer compounds to the response rates of 19 HNSCC monotherapy clinical trials. Cancer cells on top of Myogel responded less to EGFR and MEK inhibitors compared to cells cultured on plastic or Matrigel. However, we found a similar response to the PI3K/mTOR inhibitors under all culturing conditions. Cells grown on Myogel more closely resembled the response rates reported in EGFR-inhibitor monotherapy clinical trials. Our findings suggest that a human tumor matrix improves the predictability of in vitro anticancer drug testing compared to current 2D and MSDM methods.

Prognostic value of blood and lymphatic vessel markers in tongue cancer: A systematic review

Tongue squamous cell carcinoma (TSCC) has a poor prognosis due to its early metastasis through blood and lymphatic vessels. We undertook a systematic review to investigate the prognostic significance of blood microvessel density (MVD) and lymphatic vessel density (LVD) in TSCC patients. We carried out a systematic search in Ovid Medline, Scopus, and Cochrane libraries. All studies that evaluated the prognostic significance of MVD/LVD markers in TSCC were systematically retrieved. Our results showed that MVD/LVD markers, CD31, CD34, CD105, factor VIII, lymphatic vessel endothelial hyaluronan receptor‐1, and D2‐40 were evaluated in TSCC patients until 28 June 2018. Six out of 13 studies reported markers that were associated with poor prognosis in TSCC. Two out of three studies suggested that a high number of D2‐40⁺ vessels predicated low overall survival (OS); the third study reported that the ratio of D2‐40⁺ over factor VIII⁺ vessels is associated with low OS. Most of the other markers had controversial results for prognostication. We found higher expression of MVD/LVD markers were commonly, but not always, associated with shorter survival in TSCC patients. It is therefore not currently possible to recommend implementation of these markers as reliable prognosticators in clinical practice. More studies (especially for D2‐40) with larger patient cohorts are needed.

3D Culture Histology Cryosectioned Well Insert Technology Preserves the Structural Relationship between Cells and Biomaterials for Time-Lapse Analysis of 3D Cultures

When performing histology of softer biomaterials, aspiration disrupts the cellular and molecular location information. This study aims to develop a cryosectionable well insert able to preserve the biomaterial and cell's original 3D conformation from the well to histology analysis. The well insert is composed of a paraffin-coated gelatine pill. Within the coated capsule, the human epithelial cell line (NS-SV-AC) is cultured in Matrigel, GrowDex, Myogel, Myogel + GrowDex, or cell culture media for 14 days. At 0 and 14 days, the samples are frozen in liquid nitrogen and cryotome is used to create sections. The slides are stained by Sirius Red and immunohistochemistry using antibodies human collagens I-V and human Ki-67. Sirius Red shows pink shades of biomaterials and the best cellular vertical distribution throughout the sagittal section of the well is achieved with Matrigel, GrowDex, and Myogel + GrowDex; in Myogel and media, the cells sink. For collagen protein expression, only Matrigel induces a notable difference while in the other materials, collagen staining is weak or difficult to distinguish from endogenous collagens. Ki-67 expression is maintained over time. The 3D-cryo well insert provides a new time-lapse histology perspective of analysis for liquid or gel cultures that maintains cells and macromolecules in their unaltered in-well configuration.

In vitro humanized 3D microfluidic chip for testing personalized immunotherapeutics for head and neck cancer patients

OBJECTIVES

Immunotherapy and personalized medicine therapeutics are emerging as promising approaches in the management of head and neck squamous cell carcinoma (HNSCC). In spite of that, there is yet no assay that could predict individual response to immunotherapy.

METHODS

We manufactured an in vitro 3D microfluidic chip to test the efficacy of immunotherapy. The assay was first tested using a tongue cancer cell line (HSC-3) embedded in a human tumour-derived matrix "Myogel/fibrin" and immune cells from three healthy donors. Next, the chips were used with freshly isolated cancer cells, patients' serum and immune cells. Chips were loaded with different immune checkpoint inhibitors, PD-L1 antibody and IDO 1 inhibitor. Migration of immune cells towards cancer cells and the cancer cell proliferation rate were evaluated.

RESULTS

Immune cell migration towards HSC-3 cells was cancer cell density dependent. IDO 1 inhibitor induced immune cells to migrate towards cancer cells both in HSC-3 and in two HNSCC patient samples. Efficacy of PD-L1 antibody and IDO 1 inhibitor was patient dependent.

CONCLUSION

We introduced the first humanized in vitro microfluidic chip assay to test immunotherapeutic drugs against HNSCC patient samples. This assay could be used to predict the efficacy of immunotherapeutic drugs for individual patients.

MiR-455-3p, miR-150 and miR-375 are aberrantly expressed in salivary gland adenoid cystic carcinoma and polymorphous adenocarcinoma

BACKGROUND

Adenoid cystic carcinoma (AdCC) and polymorphous adenocarcinoma (PAC) are included among the most common salivary gland cancers. They share clinical and histological characteristics, making their diagnosis challenging in specific cases. MicroRNAs (miRNA) are short, non-coding RNA sequences of 19-25 nucleotides in length that are involved in post-transcriptional protein expression. They have been shown to play important roles in neoplastic and non-neoplastic processes and have been suggested as diagnostic and prognostic markers.

METHODS

This study, using quantitative RT-PCR, investigated miR-150, miR-455-3p and miR-375 expression, in order to identify a possible molecular distinction between AdCC and PAC.

RESULTS

miRNA-150 and miRNA-375 expression was significantly decreased in AdCC and PAC compared with salivary gland tissue controls, whilst miRNA-455-3p showed significantly increased expression in AdCC when compared to PAC, (P < 0.05). miR-150, miR-357 and miR-455-3p expression in AdCC, PAC and control was not associated with age, gender nor with anatomic site (major and minor salivary glands) (P > 0.05).

CONCLUSION

MiR-455-3p could be used as a complimentary tool in the diagnosis of challenging AdCC cases.

Fully Human Tumor-based Matrix in Three-dimensional Spheroid Invasion Assay

Two-dimensional cell culture-based assays are commonly used in in vitro cancer research. However, they lack several basic elements that form the tumor microenvironment. To obtain more reliable in vitro results, several three-dimensional (3D) cell culture assays have been introduced. These assays allow cancer cells to interact with the extracellular matrix. This interaction affects cell behavior, such as proliferation and invasion, as well as cell morphology. Additionally, this interaction could induce or suppress the expression of several pro- and anti-tumorigenic molecules. Spheroid invasion assay was developed to provide a suitable 3D in vitro method to study cancer cell invasion. Currently, animal-derived matrices, such as mouse sarcoma-derived matrix (MSDM) and rat tail type I collagen, are mainly used in the spheroid invasion assays. Taking into consideration the differences between the human tumor microenvironment and animal-derived matrices, a human myoma-derived matrix (HMDM) was developed from benign uterus leiomyoma tissue. It has been shown that HMDM induces migration and invasion of carcinoma cells better than MSDM. This protocol provided a simple, reproducible, and reliable 3D human tumor-based spheroid invasion assay using the HMDM/fibrin matrix. It also includes detailed instructions on imaging and analysis. The spheroids grow in a U-shaped ultra-low attachment plate within the HMDM/fibrin matrix and invade through it. The invasion is daily imaged, measured, and analyzed using ilastik and Fiji ImageJ software. The assay platform was demonstrated using human laryngeal primary and metastatic squamous cell carcinoma cell lines. However, the protocol is suitable also for other solid cancer cell lines.

Fermented Lingonberry Juice Inhibits Oral Tongue Squamous Cell Carcinoma Invasion In Vitro Similarly to Curcumin

BACKGROUND

Oral tongue squamous cell carcinoma (OTSCC) cells are highly proliferative and invasive. Lingonberry contains several polyphenolic compounds similar to curcumin. We hypothesize that fermented lingonberry juice (FLJ) has an anti-invasive and anti-proliferative effect on OTSCC cells similarly to curcumin, which is known to be anti-carcinogenic.

MATERIALS AND METHODS

FLJ, curcumin dissolved in ethanol, or curcumin loaded in Candida extracellular vesicles (EVs) were added to more (HSC-3) and less aggressive (SCC-25) OTSCC cells. Cell proliferation was measured with a 5-bromo-2'-deoxyuridine kit and invasion in the three-dimensional Myogel spheroid assay. Statistical analyses were completed with one-way ANOVA and Bonferroni post-hoc testing.

RESULTS

Both FLJ and curcumin significantly reduced the proliferation and invasion of HSC-3 and SCC-25 cells. The effects of curcumin were not improved when cells were treated with curcumin loaded within EVs.

CONCLUSION

Our results suggest that FLJ, like curcumin, has an anti-carcinogenic effect on aggressive OTSCC cells in vitro.

The prognostic value of immune checkpoints in oral squamous cell carcinoma

BACKGROUND

Despite the importance of immune checkpoints in immunotherapy, the prognostic value of these molecules remains controversial in oral squamous cell carcinoma (OSCC). We performed a systematic review to investigate the prognostic significance of the immune checkpoints in OSCC.

MATERIALS

A systematic search was conducted in Ovid Medline, Scopus and Cochrane libraries, and all studies that evaluated the prognostic significance of immune checkpoints in OSCC were systematically retrieved.

RESULTS

Twelve immune checkpoints/modulators were studied for their prognostic values in OSCC patients between 1985 and 2017. Seven immune checkpoints (FKBP51, B7-H4, B7-H6, ALHD1, PD-L1, B7-H3 and IDO1) were reported to be associated with poor patients' survival in at least one study, and five (CTLA-4, TLT-2, VISTA, PD-L2 and PD-1) did not have a significant prognostic value. PD-L1 results were controversial as it was reported to be associated with both better and worse patients' survival.

CONCLUSIONS

Even though immune checkpoint markers had high expectation for OSCC prognostication, our systematic review revealed that the majority of them had been studied only once. The other molecules, which had been studied more than once, had controversial findings, except B7-H3.

Organotypic three-dimensional assays based on human leiomyoma-derived matrices

Alongside cancer cells, tumours exhibit a complex stroma containing a repertoire of cells, matrix molecules and soluble factors that actively crosstalk between each other. Recognition of this multifaceted concept of the tumour microenvironment (TME) calls for authentic TME mimetics to study cancer in vitro. Traditionally, tumourigenesis has been investigated in non-human, three-dimensional rat type I collagen containing organotypic discs or by means of mouse sarcoma-derived gel, such as Matrigel^®. However, the molecular compositions of these simplified assays do not properly simulate human TME. Here, we review the main properties and benefits of using human leiomyoma discs and their matrix Myogel for in vitro assays. Myoma discs are practical for investigating the invasion of cancer cells, as are cocultures of cancer and stromal cells in a stiff, hypoxic TME mimetic. Myoma discs contain soluble factors and matrix molecules commonly present in neoplastic stroma. In Transwell, IncuCyte, spheroid and sandwich assays, cancer cells move faster and form larger colonies in Myogel than in Matrigel^®. Additionally, Myogel can replace Matrigel^® in hanging-drop and tube-formation assays. Myogel also suits three-dimensional drug testing and extracellular vesicle interactions. To conclude, we describe the application of our myoma-derived matrices in 3D in vitro cancer assays.

This article is part of the discussion meeting issue ‘Extracellular vesicles and the tumour microenvironment’.

Extracellular interleukin-17F has a protective effect in oral tongue squamous cell carcinoma

BACKGROUND

Oral tongue squamous cell carcinoma (SCC) is characterized by early metastasis and poor prognosis. Interleukin-17F (IL-17F) plays a protective role in many tumors. However, IL-17F expression in oral tongue SCC tissue has not been investigated.

METHODS

Immunostaining of 83 oral tongue SCC specimens and blinded-scoring were used to map IL-17F expression, location, and distribution. Survival curves were constructed according to Kaplan-Meier method. The Cox proportional hazard model was applied for univariate and multivariate survival analyses.

RESULTS

Mast cells are the major source of IL-17F in oral tongue SCC. In multivariate analysis, only the extracellular mast cell-derived IL-17F at the tumor invasion front was associated with better disease-specific survival in patients with all-stages and early-stages of oral tongue SCC.

CONCLUSION

Extracellular mast cell-derived IL-17F is antitumorigenic in oral tongue SCC. It separates patients with early-stage disease who are at high risk from patients who are at low risk. Furthermore, when analyzing tentative prognostic molecules, we conclude that in addition to the staining intensity, attention must be paid to the cellular source, distribution, and location of the molecule.

Human Tumor Tissue-Based 3D In Vitro Invasion Assays

Here we describe a protocol to utilize human benign leiomyoma tissue in in vitro 3D model that enables an assessment of cell invasion. The chapter also describes detailed instructions for image analysis to quantify the results. Leiomyoma is a benign tumor of the uterus which mimics authentic components of the tumor microenvironment including fibroblasts, vessels, collagen fibers, and extracellular protein composition. The leiomyoma invasion model represents a superior 3D model for cell invasion studies compared to the other non-human organotypic models.

Histamine H4 receptor signalling in tongue cancer and its potential role in oral carcinogenesis - a short report

PURPOSE

Recent reports indicate that histamine and its novel, high-affinity histamine H₄ receptor (H₄R) play a role in carcinogenesis, and thus H₄R signalling has become a focus of increasing interest in the pathogenesis of many cancers. The roles of H₄R in oral epithelial dysplasia (OED) and oral tongue squamous cell carcinoma (OTSCC) are unknown. The purpose of this study was to assess H₄R expression in OTSCC patients and in OTSCC-derived cell lines.

METHODS

Biopsies taken from OED, OTSCC and healthy oral mucosa were studied by immunostaining. Primary human oral keratinocytes (HOKs) and two OTSCC-derived cell lines (HSC-3 and SCC-25) were used for the in vitro studies. Quantitative real-time PCR was used to measure oncogene expression in the stimulated HOKs.

RESULTS

We found that H₄R-immunoreactivity was significantly reduced in the OED and OTSCC samples, especially in the samples with higher histopathological grades and noticeably increased mast cell counts. The presence of H₄R in HSC-3 cells had clearly waned, in contrast to the HOKs. Gene expression data indicated that histamine-relevant inflammatory and environmental elements may participate in the regulation of oncogenes.

CONCLUSIONS

Our results suggest an association between H₄R and oral carcinogenesis. Furthermore, our findings raise a potential implication of histamine-mediated factors in the regulation of oncogenes, possibly via mast cells, as crucial components of the tumor microenvironment. The identification of new elements that govern oral cancer development is highly relevant for the development of novel therapeutic approaches in OTSCC.

Crosstalk between tongue carcinoma cells, extracellular vesicles, and immune cells in in vitro and in vivo models

The crosstalk between immune cells, cancer cells, and extracellular vesicles (EVs) secreted by cancer cells remains poorly understood. We created three-dimensional (3D) cell culture models using human leiomyoma discs and Myogel to study the effects of immune cells on highly (HSC-3) and less (SCC-25) invasive oral tongue squamous cell carcinoma (OTSCC) cell lines. Additionally, we studied the effects of EVs isolated from these cell lines on the cytotoxicity of CD8⁺ T and NK cells isolated from three healthy donors. Our analysis included the effects of these EVs on innate immunity in zebrafish larvae. Activated immune cells significantly decreased the proliferation of both OTSCC cell lines and associated with a diminished invasion area of HSC-3 cells. In general, EVs from SCC-25 increased the cytotoxic activity of CD8⁺ T and NK cells more than those from HSC-3 cells. However, this effect varied depending on the source and the immune and cancer cell subgroups. In zebrafish, the amount of IL-13 mRNA was decreased by SCC-25 EVs. This study describes promising in vitro and in vivo models to investigate interactions between immune cells, cancer cells, and EVs.

Cathepsin K expression is increased in oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is an idiopathic T-cell-mediated mucosal inflammatory disease. Cathepsin K (Cat K) is one of the lysosomal cysteine proteases. It is involved in many pathological conditions, including osteoporosis and cancer. The expression and role of Cat K in OLP are unknown.

METHODS

Twenty-five oral mucosal specimens diagnosed histopathologically as OLP and fourteen healthy controls (HC) were used to study the immunohistochemical (IHC) expression of Cat K. Colocalization of Cat K with CD1a, Melan-A, CD68, CD45, mast cell tryptase (MCT), and Toll-like receptors (TLRs) 4 and 9 were studied using double IHC and/or immunofluorescence (IF) staining. Expression of Cat K was also evaluated in OLP tissue samples before and after topical tacrolimus treatment.

RESULTS

Cat K was expressed in a higher percentage of cells in the epithelial zone, and the staining intensity was stronger in the stroma in OLP compared to controls (P < 0.001). In OLP, Cat K was present mostly in melanocytes and macrophages and sporadically in basal keratinocytes, endothelial cells, and extracellularly. Cat K was found also in some fibroblasts in HC and OLP samples. Coexpression of Cat K and TLRs 4 and 9 was seen in some dendritic cells (presumably melanocytes) and macrophages. In OLP, tacrolimus treatment reduced the expression of Cat K in the epithelium but increased it in the stroma.

CONCLUSIONS

These results suggest that Cat K is involved in the pathogenesis of OLP. Cat K possibly takes part in the modulation of matrix molecules and cellular receptors.

Assessment of bone marrow lymphocytic status during tyrosine kinase inhibitor therapy and its relation to therapy response in chronic myeloid leukaemia

PURPOSE

Tyrosine kinase inhibitors (TKIs) used in the treatment of chronic myeloid leukaemia have been reported to induce immunomodulatory effects. We aimed to assess peripheral blood (PB) and bone marrow (BM) lymphocyte status at the diagnosis and during different TKI therapies and correlate it with treatment responses.

METHODS

BM and PB samples were acquired from 105 first-line TKI-treated patients. Relative number of BM lymphocytes was evaluated from MGG-stained BM aspirates, and immunophenotypic analyses were performed with multicolour flow cytometry.

RESULTS

Early 3-month expansion of BM lymphocytes was found during all different TKIs (imatinib n = 71, 20 %; dasatinib n = 25, 21 %; nilotinib n = 9, 22 %; healthy controls n = 14, 12 %, p < 0.0001). Increased PB lymphocyte count was only observed during dasatinib therapy. The BM lymphocyte expansion was associated with early molecular response; patients with 3-month BCR-ABL1 <10 % showed higher lymphocyte counts than patients with BCR-ABL1 >10 % (23 vs. 17 %, p < 0.05). Detailed phenotypic analysis showed that BM lymphocyte expansion consisted of various lymphocyte subclasses, but especially the proportion of CD19+ B cells and CD3negCD16/56+ NK cells increased from diagnostic values. During dasatinib treatment, the lymphocyte balance in both BM and PB was shifted more to cytotoxic direction (increased CD8+CD57+ and CD8+HLA-DR+ cells, and low T regulatory cells), whereas no major immunophenotypic differences were observed between imatinib and nilotinib patients.

CONCLUSIONS

Early BM lymphocytosis occurs with all current first-line TKIs and is associated with better treatment responses. PB and BM immunoprofile during dasatinib treatment markedly differs from both imatinib- and nilotinib-treated patients.

Autoinflammation Around AES Total Ankle Replacement Implants

BACKGROUND

Failure of total ankle replacement (TAR) can be characterized by early peri-implant osteolysis even in the presence of very modest numbers of wear particles. The hypothesis of the study was that this reaction is in part mediated by autoinflammatory responses mediated via damage-associated molecular patterns (DAMPs, danger signals) and pattern-recognizing danger signal receptors (PRRs).

METHODS

Peri-implant tissue and control samples from 10 patients with AES implants were immunostained for hypoxia inducible factor-1α (HIF-1α), activated caspase-3, high-mobility group box 1 (HMGB1), receptor for advanced glycation end product (RAGE), and toll-like receptors TLR2 and TLR4. Results were evaluated on a 0 to 4 scale (from 0% to >50% stained area).

RESULTS

Peri-implant tissue around failed TAR implants had a relatively high mean HIF-1α score of 3 on a scale, which however was similar in control samples. HMGB1 (a DAMP) was seen to be mobilized from nuclei to cellular cytoplasm, and the active caspase-3(+) cells were increased. All PRRs were increased in revision samples.

CONCLUSIONS

Increased expression of HMGB1 and other danger signals together with increased PRR-dependent responsiveness could contribute to autoinflammatory peri-implantitis, multilocular cyst formation, and osteolysis in failed TAR implants.

LEVEL OF EVIDENCE

Level IV, case series.

Epithelial Cell Apoptosis in Recurrent Aphthous Ulcers

A recurrent aphthous ulcer (RAU) is a common inflammatory ulcerative lesion affecting oral mucosa. We studied the eventual apoptosis of epithelial cells from the point of view of ulcer and inflammation. RAU lesions and healthy mucosa samples were immunostained for caspase-3 and high-mobility group box 1 (HMGB1). DNA nicks were identified using TUNEL staining. We studied the effects of tumor necrosis factor α (TNFα) and interferon γ (IFNγ) on the toll-like receptor 2 and 4 (TLR2 and TLR4) expression of human oral SCC-25 keratinocytes. We also studied the effects of self-DNA, all-thiol-HMGB1, and disulfide-HMGB1 on epithelial cells, with or without IFNγ. At the edge of RAU lesions, all epithelial cell layers were caspase-3+, TUNEL+, and HMGB-1+ and had widened intercellular spaces. In contrast, healthy epithelial cells were negative for caspase-3 and TUNEL staining. HMGB1 was seen in only the basal cell layers, and the cells retained close cell-to-cell contacts. Self-DNA increased TNF-α mRNA ( P = 0.02) in SCC-25 cells. Both TNFα and IFNγ ( P = 0.01) increased TLR2. Upon TNFα stimulation, SCC-25 cells lost their nuclear HMGB1 staining. HMGB1 did not increase IL-8, IL-6, or TNF-α mRNA in SCC-25 cells, which was unaffected by the presence of IFNγ. We conclude that in healthy epithelium, the most superficial cells at the end of their life cycle are simply desquamated. In contrast, RAU is characterized by top-to-bottom apoptosis such that dead cells may slough off, leading to an ulcer. Because of a lack of scavenging anti-inflammatory macrophages, apoptotic cells probably undergo secondary necrosis releasing proinflammatory danger signals, which may contribute to the peripheral inflammatory halo. This is supported by self-DNA-induced TNFα synthesis. In contrast to TLR4- and TLR2-binding lipopolysaccharide used as a positive control, disulfide-HMGB1 did not stimulate proinflammatory cytokines.

Human beta-defensin-3 producing cells in septic implant loosening

Human β-defensin-3 (hBD-3) has been found in synovial fluid and later in periprosthetic tissues in septic joint implant loosening. The aim of the present study was to identify its cellular sources. Tissue samples from 12 patients were analyzed. A fully automatic Leica BOND MAX staining robot was used. Affinity-purified rabbit anti-human hBD-3 IgG was applied in a two-layer horse radish peroxidase/anti-rabbit-labeled polymer method. Double immunofluorescence of hBD3 together with CD68, CD31, heat shock protein 47 (HSP47) and mast cell tryptase (MCT) staining was done. Human BD-3 was found in monocyte/macrophage-like cells, vascular endothelial cells and fibroblasts-like cells, but was weakly expressed in foreign body giant cells and negative in neutrophils. Human BD-3 was found in CD68 and CD31 immunoreactive cells, whereas HSP47 and MCT positive cells were hBD-3 negative. Immunostaining of hBD-3 was strong in some tissue areas but weak or absent in others. Monocyte/macrophages and endothelial cells were established in this study as the major cellular sources of hBD-3 in septic loosening, but fibroblasts and foreign body giant cells can also contribute to its production. The heterogeneous topological staining of hBD-3 suggests local regulation, possibly by bacterial products, damage-associated molecular patterns and cytokines. The results explain the increased synovial fluid/tissue concentrations of hBD-3 in septic loosening.

Sjögren's syndome and extragonadal sex steroid formation: a clue to a better disease control?

Sjögren's syndrome (SS) is an autoimmune disease characterized by lymphoplasmacytoid focal adenitis leading to mucosal dryness, with 9:1 female dominance and peak incidence at menopause. Due to autoimmune adenitis it can be speculated that the normal epithelial cell renewal has failed, possibly as a result of local intracrine failure to process dehydroepiandrosterone (DHEA) to dihydrotestosterone (DHT). Local intracrine/-cellular DHT deficiency seems to predispose to SS if estrogens are low, in menopausal women and in men. This intracrine failure could be the initial noxious stimulus, factor X, initiating the development of SS. Abnormal release and presentation of exocrine gland-derived antigens (Ag-epitopes), in a complex with major histocompatibility complex class II (MHC II), by migratory dendritic cells (DC) activates T-cells in the regional lymph nodes. B-cells with the same specificity capture and present self-Ag to Th-cells which provide T-cell help. B-cells transform to plasma cells and start to produce autoantibodies (Ab) against these T-cell-dependent Ag. Ab against SS-A/Ro and SS-B/La ribonucleoproteins occur only in HLA-DQw2.1/DQw6 heterozygous individuals, but hY-RNA and RNA polymerase III transcripts in these Ag may in all SS patients stimulate toll-like receptors (TLR) 7 and 9 of the plasmacytoid DCs, because IFN-α and IFN-signature are produced. CD8+αEβ7+cytotoxic T-cells activated via cross-presentation recirculate to attack intracrine-deficient, apoptotic epithelial cells expressing self-Ag on their surface. Exocrine glands fall into the sphere of mucosal/gut-associated lymphatic tissue. This together with immune complexes spreads the immunological memory/aggression to extra-glandular sites explaining the systemic nature of the syndrome. Secondary SS could be explained by disturbed lymphocyte recirculation. There is no conclusive evidence that SS in those few men affected is more severe than in women, suggesting that sex steroid endo-/intracrinology has its major impact on the target tissue, not on immune modulation. This article is part of a Special Issue entitled 'Essential role of DHEA'.

Histamine H4 receptor in oral lichen planus

OBJECTIVES

Oral lichen planus (OLP) is an autoimmune disease characterized by a band-like T-cell infiltrate below the apoptotic epithelial cells and degenerated basement membrane. We tested the hypothesis that the high-affinity histamine H4 receptors (H4 Rs) are downregulated in OLP by high histamine concentrations and proinflammatory T-cell cytokines.

MATERIALS AND METHODS

Immunohistochemistry and immunofluorescence staining, image analysis and quantitative real-time polymerase chain reaction of tissue samples and cytokine-stimulated cultured SCC-25 and primary human oral keratinocytes.

RESULTS

H4 R immunoreactivity was weak in OLP and characterized by mast cell (MC) hyperplasia and degranulation. In contrast to controls, H4 R immunostaining and MC counts were negatively correlated in OLP (P = 0.003). H4 R agonist at nanomolar levels led to a rapid internalization of H4 Rs, whereas high histamine concentration and interferon-γ decreased HRH4 -gene transcripts.

CONCLUSION

Healthy oral epithelial cells are equipped with H4 R, which displays a uniform staining pattern in a MC-independent fashion. In contrast, in OLP, increased numbers of activated MCs associate with increasing loss of epithelial H4 R. Cell culture experiments suggest a rapid H4 R stimulation-dependent receptor internalization and a slow cytokine-driven decrease in H4 R synthesis. H4 R may be involved in the maintenance of healthy oral mucosa. In OLP, this maintenance might be impaired by MC degranulation and inflammatory cytokines.

Increased beta 2 defensin in recurrent aphthous ulcer

OBJECTIVES

It was hypothesized that beta 2 defensin (BD-2) is increased in RAU lesions compared with healthy controls to promote anti-microbial host defence.

METHODS

RAU and control mucosa samples were subjected to quantitative real-time PCR and immunostained for BD-2, CD68, mast cell tryptase and 4-hydroxynonenal (4HNE). The effect of tumour necrosis factor-α (TNF-α) ± interleukin-17C (IL-17C), without and with vitamin K3, was studied on BD-2 expression in epithelial SCC-25 cells.

RESULTS

Although BD-2 mRNA did not differ between healthy and RAU mucosa, BD-2 stained strongly in acute-phase RAU epithelium (P = 0.001). In controls, subepithelial BD-2(+) cells were mast cells and macrophages, whereas in RAU, most infiltrating leucocytes were BD-2(+) (P = 0.004). In cell culture, BD-2 was increased 124-fold by TNF-α (P < 0.0001) and 208-fold synergistically together with IL-17C (P < 0.0001). 4HNE staining of RAU epithelium was not significantly increased, and vitamin K3-induced reactive oxygen species (ROS) did not affect BD-2.

CONCLUSIONS

Anti-microbial BD-2 was not affected by oxidative stress but was highly increased in the epithelial and immigrant cells in the acute-phase RAU lesions, probably in part synergistically by TNF-α and epithelial IL-17C, which are known to be induced by activation of danger-signal receptors by pathogen- and/or damage-associated molecular patterns.

Expression of cathepsin K in periodontitis and in gingival fibroblasts

OBJECTIVE

To study non-osteoclastic sources of cathepsin K in periodontitis.

MATERIALS AND METHODS

Tissue samples were obtained from 10 otherwise healthy periodontitis pati-ents during routine periodontal flap operations and 10 systemically and periodontally healthy individuals who underwent extraction operations for retained third molars. Methods used were immunohistochemistry, image analysis, immunofluorescence double-staining, gingival fibroblast culture, tumour necrosis factor-α (TNF-α) stimulation and Western blotting.

RESULTS

Macrophage-like cells, fibroblast-like cells, vascular endothelial cells and gingival epithelial cells were more intensively stained for cathepsin K and also more frequent in periodontitis than in controls (665 ± 104 vs 258 ± 40 cells mm(-2) , P < 0.01). Some cathepsin K(+) cells in periodontal tissues were CD68(+) , but some were CD68(-) and probably fibroblasts. Indeed, in gingival fibroblast culture, resting fibroblasts released cathepsin K, more 43 kD procathepsin K than 29 kD active cathepsin K. TNF-α increased the release of the activated cathepsin K 4- to 5-fold.

CONCLUSIONS

Results suggest that GCF-cathepsin K is not only osteoclast-derived, but in periodontitis, also other cells contribute to it. GCF-cathepsin K, perhaps together with intracellular, lysosomal collagenolytically active cathepsin K in fibroblasts, macrophages and gingival epithelial cells, can contribute to the loss of attachment and destruction of the periodontal ligament.

IL-17C and its receptor IL-17RA/IL-17RE identify human oral epithelial cell as an inflammatory cell in recurrent aphthous ulcer

BACKGROUND

Recurrent aphthous ulcer (RAU) is an ulcerative disease of non-keratinized oral mucosa. Colon and bronchial epithelial cells produce interleukin-17C (IL-17C) upon stimulation of Toll-like receptor 2 (TLR2), TLR3 and TLR5, which are highly expressed in epithelial cells in RAU lesions. We therefore investigated the eventual presence and function of IL-17C in cultured human oral keratinocytes (HOK) and control biopsies compared to RAU lesions.

METHODS

Expression of IL-17A, IL-17C, IL-17RA and IL-17RE was analysed in cultured HOK cells using quantitative real-time polymerase chain reaction (qRT-PCR). HOK cells were stimulated with IL-17C and analysed for IL-8 and tumour necrosis factor-α (TNF-α) using qRT-PCR. Control mucosa (n = 5) was immunostained for IL-17A, IL-17C, IL-8, TNF-α and mast cell tryptase and compared with RAU lesions (n = 5) using the mean grey scale value.

RESULTS

IL-17C, but no IL-17A, mRNA was found in cultured HOK cells. Components of the heterodimeric IL-17RA/IL-17RE receptor for IL-17C were also highly expressed. Stimulation of HOK with IL-17C increased TNF-α mRNA (P = 0.03; IL-8 increase was not statistically significant). HOK in RAU lesions stained intensively for IL-17C compared to controls (P = 0.006). This was associated with increased epithelial immunostaining of TNF-α (P = 0.04) and IL-8 (P = 0.02). Most of the inflammatory cells which stained for IL-17A in control mucosa and RAU lesions were also mast cell tryptase positive.

CONCLUSION

IL-17C is highly expressed in epithelial cells in RAU lesions, where it seems to stimulate oral keratinocytes via IL-17RA/IL-17RE to produce pro-inflammatory cytokines. Human oral epithelial cells are probably important inflammatory cells in RAU.

Do changing toll-like receptor profiles in different layers and grades of osteoarthritis cartilage reflect disease severity?

OBJECTIVE

Cartilage degeneration in osteoarthritis (OA) leads to release of potential danger signals. The aim of our study was to profile OA cartilage for the Toll-like receptor (TLR) danger signal receptors.

METHODS

Osteochondral cylinders from total knee replacements were graded using OA Research Society International score and stained for proteoglycans, collagenase-cleaved type II collagen, and TLR 1-10, which were analyzed histomorphometrically.

RESULTS

Grade 1 OA lesions contained 22%-55% TLR 1-9-positive cells in the surface zone, depending on the TLR type. In Grade 2 TLR, immunoreactivity was 60%-100% (p < 0.01) and it was even higher in Grades 3 and 4 (p < 0.01 vs Grade 1). TLR-positive cells in Grade 1 middle zone were low, 0-19.9%, but were 5.1%-32.7% in Grade 2 (p < 0.01) and 34%-83% in Grades 3-4 samples (p < 0.001). TLR values in Grade 5 were low (14.3%-28.7%; p < 0.001). In Grades 3-4 OA, cartilage matrix stained strongly for TLR. In Grade 1, COL2-3/4M was restricted to chondrocytes, but was increasingly seen in matrix upon progress of OA to Grade 4, and then declined.

CONCLUSION

Cells in the gliding surface zone are fully equipped with TLR in mild OA. Their proportion increases and extends to the middle or even the deep zone, reflecting OA progression. COL2A-3/4M staining suggests Endo180-mediated intake for intralysosomal degradation by cathepsins in Grade 1, but in higher grades this chondrocyte-mediated clearance fails and the matrix demonstrates extensive collagenase-induced damage. Detached and/or partially degraded matrix components can then act as endogenous danger signals (damage-associated molecular patterns or DAMP) and stimulate increasingly TLR-equipped chondrocytes to inflammation. At the peak inflammatory response, soluble TLR may exert negative feedback, explaining in part the low TLR levels in Grade 5 OA.

Recurrent aphthous ulcers--a Toll-like receptor-mediated disease?

BACKGROUND

Recurrent aphthous ulcer (RAU) is characterized by acute and painful inflammatory ulcerations, which heal spontaneously but tend to recur. Many pathogens have been proposed as causative agents, but none has been consistently proven. According to our hypothesis, RAU is an autoinflammatory disorder triggered by pathogen-associated molecular patterns (PAMPs) shared by different pathogenic and commensal microbes.

METHODS

PAMP-reactive Toll-like receptors (TLRs) were mapped in oral epithelium in healthy controls compared to RAU.

RESULTS

In controls, the superficial epithelium formed a TLR(-), a PAMP non-reactive physical barrier zone, but all TLRs were found deeper in the epithelium, usually restricted to suprabasal and basal cell layers. In RAU, the epithelial TLR polarity was lost: TLRs 1, 2, 5, 7, and 8 were found throughout the epithelium, but also TLRs 4, 6, and 10 extended higher up than normally, whereas TLR-3 was almost lost in RAU. In RAU lesions, connective tissue stroma was heavily infiltrated by TLR(+) inflammatory cells.

CONCLUSIONS

Normal TLR architecture prevents inflammatory responses against normal microbes but still contains a deep TLR(+) , PAMP-reactive dormant defense zone. In RAU, the TLR(+), PAMP-reactive zone extends to surface or subsurface exposed to microbial PAMPs. TLR reactivity is further enhanced by recruitment of inflammatory leukocytes forming a new deep line of defense. The organization of the TLR system in healthy mucosa and its changes in RAU are compatible with active pathogenic involvement of TLRs, which together with the typical clinical picture and course suggest that RAU is a TLR-mediated disease.