Nerve growth factor receptor (p75 NTR) and pattern of invasion predict poor prognosis in oral squamous cell carcinoma

CSChighE-cadherinlow immunohistochemistry panel predicts poor prognosis in oral squamous cell carcinoma

Identifying marker combinations for robust prognostic validation in primary tumour compartments remains challenging. We aimed to assess the prognostic significance of CSC markers (ALDH1, CD44, p75NTR, BMI-1) and E-cadherin biomarkers in OSCC. We analysed 94 primary OSCC and 67 metastatic lymph node samples, including central and invasive tumour fronts (ITF), along with clinicopathological data. We observed an increase in ALDH1+/CD44+/BMI-1- tumour cells in metastatic lesions compared to primary tumours. Multivariate analysis highlighted that elevated p75NTR levels (at ITF) and reduced E-cadherin expression (at the tumour centre) independently predicted metastasis, whilst ALDH1high exhibited independent predictive lower survival at the ITF, surpassing the efficacy of traditional tumour staging. Then, specifically at the ITF, profiles characterized by CSChighE-cadherinlow (ALDH1highp75NTRhighE-cadherinlow) and CSCintermediateE-cadherinlow (ALDH1 or p75NTRhighE-cadherinlow) were significantly associated with worsened overall survival and increased likelihood of metastasis in OSCC patients. In summary, our study revealed diverse tumour cell profiles in OSCC tissues, with varying CSC and E-cadherin marker patterns across primary tumours and metastatic sites. Given the pivotal role of reduced survival rates as an indicator of unfavourable prognosis, the immunohistochemistry profile identified as CSChighE-cadherinlow at the ITF of primary tumours, emerges as a preferred prognostic marker closely linked to adverse outcomes in OSCC.

The mechanisms of action of metformin on head and neck cancer in the pre-clinical setting: a scoping review

This scoping review identifies the mechanistic pathways of metformin when used to treat head and neck cancer cells, in the pre-clinical setting. Understanding the underlying mechanisms will inform future experimental designs exploring metformin as a potential adjuvant for head and neck cancer. This scoping review was conducted according to the Joanna-Briggs Institute framework. A structured search identified 1288 studies, of which 52 studies fulfilled the eligibility screen. The studies are presented in themes addressing hallmarks of cancer. Most of the studies demonstrated encouraging anti-proliferative effects in vitro and reduced tumor weight and volume in animal models. However, a few studies have cautioned the use of metformin which supported cancer cell growth under certain conditions.

Nerve Growth Factor and the Role of Inflammation in Tumor Development

Nerve growth factor (NGF) plays a dual role both in inflammatory states and cancer, acting both as a pro-inflammatory and oncogenic factor and as an anti-inflammatory and pro-apoptotic mediator in a context-dependent way based on the signaling networks and its interaction with diverse cellular components within the microenvironment. This report aims to provide a summary and subsequent review of the literature on the role of NGF in regulating the inflammatory microenvironment and tumor cell growth, survival, and death. The role of NGF in inflammation and tumorigenesis as a component of the inflammatory system, its interaction with the various components of the respective microenvironments, its ability to cause epigenetic changes, and its role in the treatment of cancer have been highlighted in this paper.

Receptor, Signal, Nucleus, Action: Signals That Pass through Akt on the Road to Head and Neck Cancer Cell Migration

This review aims to provide evidence for the role of the tumour microenvironment in cancer progression, including invasion and metastasis. The tumour microenvironment is complex and consists of tumour cells and stromal-derived cells, in addition to a modified extracellular matrix. The cellular components synthesise growth factors such as EGF, TGFα and β, VEGF, and NGF, which have been shown to initiate paracrine signalling in head and neck cancer cells by binding to cell surface receptors. One example is the phosphorylation, and hence activation, of the signalling protein Akt, which can ultimately induce oral cancer cell migration in vitro. Blocking of Akt activation by an inhibitor, MK2206, leads to a significant decrease, in vitro, of cancer-derived cell migration, visualised in both wound healing and scatter assays. Signalling pathways have therefore been popular targets for the design of chemotherapeutic agents, but drug resistance has been observed and is related to direct tumour-tumour cell communication, the tumour-extracellular matrix interface, and tumour-stromal cell interactions. Translation of this knowledge to patient care is reliant upon a comprehensive understanding of the complex relationships present in the tumour microenvironment and could ultimately lead to the design of efficacious treatment regimens such as targeted therapy or novel therapeutic combinations.

Inhibition of tumor suppressor p73 by nerve growth factor receptor via chaperone-mediated autophagy

The tumor suppressr p73 is a homolog of p53 and is capable of inducing cell cycle arrest and apoptosis. Here, we identify nerve growth factor receptor (NGFR, p75NTR, or CD271) as a novel negative p73 regulator. p73 activates NGFR transcription, which, in turn, promotes p73 degradation in a negative feedback loop. NGFR directly binds to p73 central DNA-binding domain and suppresses p73 transcriptional activity as well as p73-mediated apoptosis in cancer cells. Surprisingly, we uncover a previously unknown mechanism of NGFR-facilitated p73 degradation through the chaperone-mediated autophagy (CMA) pathway. Collectively, our studies demonstrate a new oncogenic function for NGFR in inactivating p73 activity by promoting its degradation through the CMA.

Metformin inhibits proliferation of oral squamous cell carcinoma cells by suppressing proteolysis of nerve growth factor receptor

OBJECTIVE

We aimed to explore the effects of metformin on oral squamous cell carcinoma (OSCC) cell proliferation and the associated molecular mechanisms.

METHODS

We established an OSCC model in SCC15 cells overexpressing nerve growth factor receptor (NGFR) or the N-terminal region (aa 1-250; NGFR-N), and assessed cell proliferation by CCK-8 assay, colony formation assay, and cell cycle analysis. Levels of NGFR and related genes and proteins were detected by qPCR and western blotting, and NGFR and NGFR-N affinity for p53 was assessed by immunoprecipitation assay. Additionally, the effects of NGFR and NGFR-N on p53 binding with its downstream gene promoters were analyzed by chromatin immunoprecipitation.

RESULTS

Metformin inhibited OSCC cell proliferation and blocked NGFR proteolysis, thereby reducing the generation of its intracellular domain and NGFR-N. Moreover, compared with NGFR, NGFR-N showed higher affinity for p53 and more strongly inactivated p53 to promote cell proliferation. Furthermore, upregulation of NGFR-N downregulated levels of p53-specific downstream transcripts and proteins, whereas these levels were significantly upregulated in metformin-treated cells overexpressing NGFR.

CONCLUSIONS

These results showed that metformin inhibited cell proliferation by suppressing NGFR proteolysis, thereby promoting its antitumor effect in OSCC and offering novel insight into a role for metformin in OSCC treatment.

Cancer stem cells enrichment with surface markers CD271 and CD44 in human head and neck squamous cell carcinomas

Head and neck squamous cell carcinoma (HNSCC) has a poor 5-year survival rate of 50%. One potential reason for treatment failure is the presence of cancer stem cells (CSCs). Several cell markers, particularly CD44, have been used to isolate CSCs. However, isolating a pure population of CSC in HNSCC still remains a challenging task. Recent findings show that normal oral stem cells were isolated using CD271 as a marker. Thus, we investigated the combined use of CD271 and CD44 to isolate an enriched subpopulation of CSCs, followed by their characterization in vitro, in vivo, and in patients' tissue samples. Fluorescent-activated cell sorting was used to isolate CD44+/CD271+ and CD44+/CD271- from two human HNSCC cell lines. Cell growth and self-renewal were measured with MTT and sphere/colony formation assays. Treatment-resistance was tested against chemotherapy (cisplatin and 5-fluorouracil) and ionizing radiation. Self-renewal, resistance, and stemness-related genes expression were measured with qRT-PCR. In vivo tumorigenicity was tested with an orthotopic immunodeficient mouse model of oral cancer. Finally, we examined the co-localization of CD44+/CD271+ in patients' tissue samples. We found that CD271+ cells were a subpopulation of CD44+ cells in human HNSCC cell lines and tissues. CD44+/CD271+ cells exhibited higher cell proliferation, sphere/colony formation, chemo- and radio-resistance, upregulation of CSCs-related genes, and in vivo tumorigenicity when compared to CD44+/CD271- or the parental cell line. These cell markers showed increased expression in patients with the increase of the tumor stage. In conclusion, using both CD44 and CD271 allowed the isolation of CSCs from HNSCC. These enriched CSCs will be more relevant in future treatment and HNSCC progression studies.

Impact of Histological and Molecular Parameters on Prognosis of Oral Squamous Cell Carcinoma: Analysis of 290 Cases

Background

Nodal metastasis is a critical factor in predicting the prognosis of oral squamous cell carcinoma (OSCC). When patients present with a clinically positive neck, the treatment of choice is radical neck dissection. However, management of a clinically negative neck is still a subject of significant controversy.

Aim

This study was carried out in order to propose a model to predict regional lymph node metastasis of OSCC using histological parameters such as tumour stage, tumour size, pattern of invasion (POI), differentiation of tumour, and host immune response, together with the expression levels of six biomarkers (periostin, HIF-1α, MMP-9, β-catenin, VEGF-C, and EGFR), and, furthermore, to compare the impact of all these parameters on recurrence and 3 yr and 5 yr survival rates. Materials and Method. Histological materials collected from the archives were used to evaluate histological parameters and immunohistochemical profiles. Standard methods were used for immunohistochemistry and for evaluation of results. Data related to recurrence and survival (3 and 5 years) was also recorded. Clinical data was collected from patients' records.

Results

Male to female ratio was 3 : 1. The commonest site of OSCC was the buccal mucosa, and majority of them were T3 or T4 tumours presented at stage 4. 62.5% of the tumours were well differentiated. Three-year and 5-year survival rates were significantly associated with lymph node metastasis and recurrence. POI was significantly correlated with tumour size, stage, 3-year survival, EGFR, HIF-1α, periostin, and MMP-9 (p < 0.05). Expression of EGFR showed a direct association with metastasis (p < 0.05).

Conclusion

POI, level of differentiation, and expression of EGFR are independent prognostic markers for lymph node metastasis. Therefore, these parameters may help in treatment planning of a clinically negative neck.

NADPH oxidase 5α promotes the formation of CD271 tumor-initiating cells in oral cancer

Oral tongue squamous cell carcinoma (OTSCC) has a distinctive cell sub-population known as tumor-initiating cells (TICs). CD271 is a functional TIC receptor in head and neck cancers. The molecular mechanisms governing CD271 up-regulation remains unclear. Oxidative stress is a contributing factor in TIC development. Here, we explored the potential role of NADPH oxidase 5 (NOX5) and its regulatory mechanism on the development of CD271-expressing OTSCC. Our results showed that the splice variant NOX5α is the most prevalent form expressed in head and neck cancers. NOX5α enhanced OTSCC proliferation, migration, and invasion. Overexpression of NOX5α increased the size of OTSCC xenograft significantly in vivo. The tumor-promoting functions of NOX5α were mediated through the reactive oxygen species (ROS)-generating property. NOX5α activated ERK singling and increased CD271 expression at the transcription level. Also, NOX5α reduces the sensitivity of OTSCC to cisplatin and natural killer cells. The findings indicate that NOX5α plays an important part in the development of TIC in OTSCC.

Physiology, Pathology and Regeneration of Salivary Glands

Salivary glands are essential structures in the oral cavity. A variety of diseases, such as cancer, autoimmune diseases, infections and physical traumas, can alter the functionality of these glands, greatly impacting the quality of life of patients. To date, no definitive therapeutic approach can compensate the impairment of salivary glands, and treatment are purely symptomatic. Understanding the cellular and molecular control of salivary glands function is, therefore, highly relevant for therapeutic purposes. In this review, we provide a starting platform for future studies in basic biology and clinical research, reporting classical ideas on salivary gland physiology and recently developed technology to guide regeneration, reconstruction and substitution of the functional organs.

Cathepsin B defines leader cells during the collective invasion of salivary adenoid cystic carcinoma

Cathepsin B (CTSB) has been reported to be involved in cancer metastasis by altering extracellular matrix (ECM) remodeling and facilitating invasion. However, the contribution of CTSB to collective cell invasion in salivary adenoid cystic carcinoma (SACC) and the underlying mechanisms remain unclear. The present study demonstrated that collective cell invasion is commonly observed in SACC without a complete epithelial-mesenchymal transition signature. CTSB was found to be overexpressed in the invasive front of SACC compared to the tumor center, and was associated with a poor prognosis of patients with SACC. Subsequently, a 3D spheroid invasion assay was established in order to recapitulate the collective cell invasion of SACC and the results revealed that CTSB was only expressed in leader cells. The knockdown of CTSB by siRNA inhibited the migration and invasion of SACC-83 cells and impaired the formation of leader cells. CTSB knockdown also disrupted cytoskeletal organization, altered cell morphology and inhibited ECM remodeling by downregulating matrix metalloproteinase-9, focal adhesion kinase and Rho/ROCK function. Therefore, the present study provides evidence that CTSB may define leader cells in SACC and is required for collective cell invasion as a potential key regulator of ECM remodeling.

Weighted gene co‑expression network analysis for identifying hub genes in association with prognosis in Wilms tumor

Wilms tumor (WT) is the most common type of renal malignancy in children. Survival rates are low and high-risk WT generally still carries a poor prognosis. To better elucidate the pathogenesis and tumorigenic pathways of high-risk WT, the present study presents an integrated analysis of RNA expression profiles of high-risk WT to identify predictive molecular biomarkers, for the improvement of therapeutic decision-making. mRNA sequence data from high-risk WT and adjacent normal samples were downloaded from The Cancer Genome Atlas to screen for differentially expressed genes (DEGs) using R software. From 132 Wilms tumor samples and six normal samples, 2,089 downregulated and 941 upregulated DEGs were identified. In order to identify hub DEGs that regulate target genes, weighted gene co-expression network analysis (WGCNA) was used to identify 11 free-scale gene co-expressed clusters. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were annotated using KEGG Orthology Based Annotation System annotation of different module genes. The Search Tool for the Retrieval of Interacting Genes was used to construct a protein-protein interaction network for the identified DEGs, and the hub genes of WGCNA modules were identified using the Cytohubb plugin with Cytoscape software. Survival analysis was subsequently performed to highlight hub genes with a clinical signature. The present results suggest that epidermal growth factor, cyclin dependent kinase 1, endothelin receptor type A, nerve growth factor receptor, opa-interacting protein 5, NDC80 kinetochore complex component and cell division cycle associated 8 are essential to high-risk WT pathogenesis, and they are closely associated with clinical prognosis.

Immunohistochemistry profile of p75 neurotrophin receptor in oral epithelial dysplasia and oral squamous cell carcinoma induced by 4-nitroquinoline 1-oxide in rats

OBJECTIVE

The 4-nitroquinoline 1-oxide (4-NQO) model for carcinogenesis has been used to investigate cancer stem cells (CSC), but no study has addressed the role of the p75 neurotrophin receptor (p75NTR) in 4-NQO-induced oral dysplasia and oral squamous cell carcinoma (OSCC). The aim of this study was to evaluate the immunohistochemistry profile of the p75NTR during 4-NQO-induced oral carcinogenesis in rats and to verify whether this profile has an association with proliferating cell nuclear antigen (PCNA) immunolabeling.

DESIGN

For 28 weeks, rats were exposed to 4-NQO, which was diluted in the drinking water. After 3, 5, 7, 16, and 28 weeks, the animals were euthanized and their tongues were histologically analyzed using p75NTR and PCNA immunolabeling.

RESULTS

In animals without 4-NQO exposure, the p75NTR and PCNA were expressed only in the basal epithelial layer and in a clustered manner. The oral epithelium showed dysplasia and a significant increase in the number of p75NTR- and PCNA-positive cells, which were localized mainly in the basal and suprabasal epithelial layers during weeks 5-16 of 4-NQO exposure. When the epithelium invaded the lamina propria and well-differentiated OSCC began, the p75NTR-positive cell frequency drastically decreased in epithelial cords and nests, showing a negative correlation with PCNA expression. p75NTR immunolabeling during 4-NQO-induced carcinogenesis was similar to that described for human head and neck dysplasia and neoplasia.

CONCLUSIONS

p75NTR immunolabeling observed in 4-NQO-induced oral dysplastic and OSCC lesions were related to the early phases of oral carcinogenesis and may help predict cell dysplasia and malignant transformation.

Nerve Growth Factor (NGF)-Receptor Survival Axis in Head and Neck Squamous Cell Carcinoma

Neurotrophins and their receptors might regulate cell survival in head and neck squamous cell carcinoma (HNSCC). mRNA expression of nerve growth factor (NGF) and protein synthesis of high (NTRK1) and low affinity neurotrophin (p75 neurotrophin receptor; NTR) receptors were investigated in normal oral mucosa and in HNSCC. HNSCC cell lines were treated with mitomycin C (MMC) and cell survival was investigated. Normal and malignant epithelial cells expressed NGF mRNA. NTRK1 was upregulated in 80% of HNSCC tissue, and 50% of HNSCC samples were p75NTR positive. Interestingly, in HNSCC tissue: NTRK1 and p75NTR immunohistochemical reactions were mutually exclusive. Detroit 562 cell line contained only p75NTR, UPCI-SCC090 cells synthesized NTRK1 but not p75NTR and SCC-25 culture had p75NTR and NTRK1 in different cells. NGF (100 ng/mL) significantly improved (1.4-fold) the survival of cultured UPCI-SCC090 cells after MMC-induced cell cycle arrest, while Detroit 562 cells with high levels of p75NTR did not even get arrested by single short MMC treatment. p75NTR in HNSCC might be related with NGF-independent therapy resistance, while NTRK1 might transduce a survival signal of NGF and contribute in this way to improved tumor cell survival after cell cycle arrest.

CD271 Confers an Invasive and Metastatic Phenotype of Head and Neck Squamous Cell Carcinoma through the Upregulation of Slug

Purpose: Head and neck squamous cell carcinoma (HNSCC) is comprised of heterogeneous populations of cells, and CD271 (NGFR; p75NTR) has been associated with a tumor-initiating cell subpopulation. This study assessed the role of CD271 in modulating metastatic behavior in HNSCC.Experimental Design: CD271 was overexpressed in murine and human oral squamous cell carcinoma cells to assess the impact of CD271 activation on the invasive and metastatic phenotype of these cells, using in vitro and orthotopic in vivo modeling. Treatment with human nerve growth factor (NGF) to activate CD271, as well as shRNA knockdown of the CD271-upregulated Snai2 expression, was used to assess the mechanism of the CD271-induced invasive phenotype. Relevance of CD271 expression in human HNSCC was evaluated in patient-derived xenografts (PDX) and primary human oral cancers, annotated with clinical behavior characteristics and survival data.Results: Forced expression of CD271 resulted in a more invasive and metastatic phenotype. Slug, an epithelial-to-mesenchymal transition (EMT)-related transcription factor, encoded by Snai2, was highly expressed in MOC2-CD271 and HSC3-CD271, compared with respective parental cells. CD271 activation by NGF conferred enhanced invasiveness in CD271-overexpressing cells, which was abrogated by Snai2 knockdown. In PDXs and primary human HNSCC, CD271 expression correlated with higher Snai2 expression, greater nodal metastasis, and shorter disease-free survival.Conclusions: Activation of CD271 results in upregulation of Snai2/Slug, which, in turn, results in a more invasive phenotype and an enhanced capacity for metastasis to regional lymph nodes. These findings point to CD271 as a promising, therapeutic target for oral cancer metastasis. Clin Cancer Res; 24(3); 674-83. ©2017 AACR.

Generation and characterization of a human oral squamous carcinoma cell line SCC-9 with CRISPR/Cas9-mediated deletion of the p75 neurotrophin receptor

OBJECTIVE

To investigate the importance of the p75 neurotrophin receptor (p75^NTR) in human tongue squamous carcinoma cells, we exploited the CRISPR/Cas9 technology to establish a p75^NTR-knockout SCC-9 cell line and to explore the effect on biological functions.

MATERIALS AND METHODS

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated endonuclease (Cas9) system was used to generate genomic deletion mutants of p75^NTR in the tongue squamous carcinoma cell lines SCC-9. Single-guide RNA (sgRNA) sequences were designed to target the p75^NTR genomic sequence and were cloned into plasmid pGK1.1. The linearized vector was electroporated into SCC-9 cells and p75^NTR deletion was confirmed using Cruiser™ enzyme digestion and PCR amplification. SCC-9 clones with successful deletion of p75^NTR were identified and verified by sequencing and selected for functional testing in cell proliferation, invasion, migration, and colony-forming assays.

RESULTS

Compared with control cells, p75^NTR-knockout SCC-9 cells showed significantly diminished abilities to proliferate, invade, migrate, and form colonies, indicating a reduction in pro-tumorigenic behavior.

CONCLUSION

These data demonstrate, first, that the CRISPR/Cas9 system is a simplified method for generating p75^NTR knockouts with relatively high efficiency, and second, that deletion of p75^NTR suppresses several tumor-promoting properties of SCC-9 cells, suggesting that p75^NTR is a potential target for the development of novel therapies for tongue cancer.

p75 neurotrophin receptor: A potential surface marker of tongue squamous cell carcinoma stem cells

The present study detected p75 neurotrophin receptor (p75^NTR) expression in tongue squamous cell carcinoma (TSCC) cell lines, in order to define the biological properties of p75^NTR+ cells and to confirm the use of p75^NTR+ as a surface marker for TSCC stem cells. p75^NTR+ cells were separated from Tca-8113 and CAL-27 TSCC cells by fluorescence-activated cell sorting. Colony formation, MTT and scratch assays, and a tumorigenicity analysis were performed to measure self-renewal and proliferation, multidirectional differentiation, and tumorigenicity of p75^NTR+ cells. p75^NTR+ cells comprised 3.1 and 1.9% of Tca-8113 and CAL-27 cells (mean of three experiments), respectively, and were more able to form colonies compared with non-sorted cells (P<0.01). In addition, the proportion of p75^NTR+ cells generated from monoclonal p75^NTR+ cells decreased to 14.5 (Tca-8113) and 5.8% (CAL-27) of cells within 2 weeks, thus suggesting that p75^NTR+ cells are able to generate p75^NTR+ and p75^NTR− cells. Furthermore, p75^NTR+ cells exhibited increased proliferation, as evidenced by MTT assay (P<0.01) and had greater metastatic ability according to the scratch assay (P<0.01), compared with non-sorted cells. p75^NTR+ cells also exhibited a greater tumorigenic capacity compared with non-sorted cells. In conclusion, p75^NTR+ cells isolated from TSCC cell lines possess the characteristics of cancer stem cells; therefore, p75^NTR may be considered a useful surface marker for the identification of TSCC stem cells.

The Role of Nerve Growth Factor (NGF) and Its Precursor Forms in Oral Wound Healing

Nerve growth factor (NGF) and its different precursor forms are secreted into human saliva by salivary glands and are also produced by an array of cells in the tissues of the oral cavity. The major forms of NGF in human saliva are forms of pro-nerve growth factor (pro-NGF) and not mature NGF. The NGF receptors tropomyosin-related kinase A (TrkA) and p75 neurotrophin receptor (p75^NTR) are widely expressed on cells in the soft tissues of the human oral cavity, including keratinocytes, endothelial cells, fibroblasts and leukocytes, and in ductal and acinar cells of all types of salivary glands. In vitro models show that NGF can contribute at most stages in the oral wound healing process: restitution, cell survival, apoptosis, cellular proliferation, inflammation, angiogenesis and tissue remodeling. NGF may therefore take part in the effective wound healing in the oral cavity that occurs with little scarring. As pro-NGF forms appear to be the major form of NGF in human saliva, efforts should be made to study its function, specifically in the process of wound healing. In addition, animal and clinical studies should be initiated to examine if topical application of pro-NGF or NGF can be a therapy for chronic oral ulcerations and wounds.

BEX3 contributes to cisplatin chemoresistance in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) can develop cisplatin‐resistant phenotype. Research has revealed that enriched in cancer stem cell population is involved in developing cisplatin‐resistant phenotype. CD271 is a candidate stem cell maker in head and neck cancers. The CD receptor does not possess any enzymatic property. Signal transduction function of CD271 is mediated by the cellular receptor‐associated protein. Our data showed that Brain‐expressed X‐linked 3 (BEX3), a CD271 receptor‐associated protein, was overexpressed in NPC. BEX3 overexpression was a unique event in cancer developed in the head and neck regions, especially NPC. BEX3 expression was inducible by cisplatin in NPC. In cisplatin‐resistant NPC xenograft, treatment with nontoxic level of cisplatin led to a remarkable increase in BEX3 level. High BEX3 expression was accompanied with high octamer‐binding transcription factor 4 (OCT4) expression in cisplatin‐resistant NPC. To confirm the inducing role of BEX3 on OCT4 expression, we knockdown BEX3 using siRNA and compared the expression of OCT4 with mock transfectants. Suppressing BEX3 transcripts led to a significant reduction in OCT4. In addition, targeting BEX3 using shRNA could increase the sensitivity of NPC cells to cisplatin. In summary, our results indicated a unique functional role of BEX3 in mediating the sensitivity of NPC cells to cisplatin. Targeting or blocking BEX3 activity might be useful in reversing the cisplatin‐resistant phenotype in NPC.

Expression of epithelial-mesenchymal transition markers at the invasive front of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common malignances. In epithelial-mesenchymal transition (EMT), epithelial cells switch to mesenchymal-like cells exhibiting high mobility. This migratory phenotype is significant during tumor invasion and metastasis.

P75 neurotrophin receptor expression in squamous cell carcinoma

P75 neurotrophin receptor (p75) is a transmembrane protein in the tumor necrosis receptor superfamily useful for the diagnosis of desmoplastic melanomas, desmoplastic trichoepitheliomas, and more recently used for detecting perineural invasion in oral and esophageal squamous cell carcinomas (SCCs). P75 staining in cutaneous SCCs is more controversial with initial staining reported as negative but more recent reports indicating that it may be a useful immunohistochemical marker of perineural invasion. A poorly differentiated pleomorphic epithelioid cell proliferation, which had strong p75 staining in the periphery of epithelioid cell nests, is being reported. Both low and high molecular weight keratins were positive and SOX10, S100, and HMB-45 staining were negative, consistent with a poorly differentiated SCC. To our knowledge, this pattern has not yet been reported and most likely reflects reiteration of the basal layer epithelium, which normally stains positively for p75. Reports of p75 staining in cutaneous SCCs are still limited, and a larger scale study may prove useful in determining its role as a marker for perineural invasion.

Modes of cancer cell invasion and the role of the microenvironment

Metastasis begins with the invasion of tumor cells into the stroma and migration toward the blood stream. Human pathology studies suggest that tumor cells invade collectively as strands, cords and clusters of cells into the stroma, which is dramatically reorganized during cancer progression. Cancer cells in intravital mouse models and in vitro display many 'modes' of migration, from single isolated cells with round or elongated phenotypes to loosely-/non-adherent 'streams' of cells or collective migration of cell strands and sheets. The tumor microenvironment, and in particular stroma organization, influences the mode and dynamics of invasion. Future studies will clarify how the combination of stromal network structure, tumor cell signaling and extracellular signaling cues influence cancer cell migration and metastasis.

CD271 is a functional and targetable marker of tumor-initiating cells in head and neck squamous cell carcinoma

Tumor-initiating cells (TICs) in squamous cell carcinoma of the head and neck (SCCHN) are best characterized by their surface expression of CD44. Although there is great interest in identifying strategies to target this population, no marker of these cells has been found to be functionally active. Here, we examined the expression of the purported marker of normal human oral epithelial stem cells, CD271. We show that CD271 expression is restricted to a subset of the CD44⁺ cells. Using xenograft assays, we show that the CD44⁺CD271⁺ subpopulation contains the most tumorigenic cells. Loss of CD271 function results in a block in the G2-M phase of the cell cycle and a profound negative impact on the capacity of these cells to initiate tumor formation in vivo. Incubation with recombinant NGF results in enhanced phosphorylation of Erk, providing additional evidence that CD271 is functionally active. Finally, incubation of SCCHN cells with antibody to CD271 results in decreased Erk phosphorylation and decreased tumor formation in vivo. Thus, our data are the first to demonstrate that CD271 more specifically identifies the TIC subpopulation within the CD44⁺ compartment in SCCHN and that this receptor is a functionally active and targetable molecule.

The translational significance of epithelial-mesenchymal transition in head and neck cancer

Positive markers of epithelial-mesenchymal transition (EMT) in head and neck cancers complicate clinical management and are associated with reduced survival. We discuss recent translational discoveries in EMT and suggest additional actionable molecular pathways, biomarkers, and clinical agents.

The low-affinity nerve growth factor receptor p75NTR identifies a transient stem cell-like state in oral squamous cell carcinoma cells

BACKGROUND

Although several markers have been used for enrichment of cells with stem cell-like properties in oral squamous cell carcinoma (OSCC), isolation of a pure subpopulation is still a challenging task. Normal oral and esophageal keratinocyte stem cells have been previously isolated using the low-affinity nerve growth factor receptor p75NTR.

OBJECTIVE

To investigate the potential of p75NTR as a marker for identification and isolation of oral cancer cells with stem cell-like properties.

METHODS

Subpopulations of cells with high or low expression of p75NTR were sorted from OSCC-derived cells and compared for sphere/colony formation, in vivo tumor formation ability, expression of stem cell-related molecules, cell cycle distribution and drug resistance.

RESULTS

p75NTR(High) cells exhibited statistically significant higher stem cell properties than p75NTR(Low) cells in all assays performed. Nevertheless, p75NTR(Low) subpopulation did also exhibit some stem cell features, but to a lesser extent. Propagation of p75NTR(Low) cells for several passages in culture showed that the expression of p75NTR could rise spontaneously. This finding was also supported by the similar expression of p75NTR by the xenografts generated by both subpopulations in NOD\SCID IL2Rg(null) mice.

CONCLUSION

p75NTR can be used for isolating a subpopulation enriched for cells with stem cell-like properties in OSCC. De novo generation of p75NTR(High) cells from p75NTR(Low) cells suggests either that there is another subpopulation with stem cell features within the p75NTR(Low) cells, or that the p75NTR(Low) cells can dedifferentiate due to a contextually regulated equilibrium between stem cell-like cells and transit-amplifying neoplastic progenitors.

Role of p75 neurotrophin receptor in stem cell biology: more than just a marker

p75(NTR), the common receptor for both neurotrophins and proneurotrophins, has been widely studied because of its role in many tissues, including the nervous system. More recently, a close relationship between p75(NTR) expression and pluripotency has been described. p75(NTR) was shown to be expressed in various types of stem cells and has been used to prospectively isolate stem cells with different degrees of potency. Here, we give an overview of the current knowledge on p75(NTR) in stem cells, ranging from embryonic to adult stem cells, and cancer stem cells. In an attempt to address its potential role in the control of stem cell biology, the molecular mechanisms underlying p75(NTR) signaling in different models are also highlighted. p75(NTR)-mediated functions include survival, apoptosis, migration, and differentiation, and depend on cell type, (pro)neurotrophin binding, interacting transmembrane co-receptors expression, intracellular adaptor molecule availability, and post-translational modifications, such as regulated proteolytic processing. It is therefore conceivable that p75(NTR) can modulate cell-fate decisions through its highly ramified signaling pathways. Thus, elucidating the potential implications of p75(NTR) activity as well as the underlying molecular mechanisms of p75(NTR) will shed new light on the biology of both normal and cancer stem cells.

Depth of invasion, tumor budding, and worst pattern of invasion: prognostic indicators in early-stage oral tongue cancer

Background

Oral (mobile) tongue squamous cell carcinoma (SCC) is characterized by a highly variable prognosis in early-stage disease (T1/T2 N0M0). The ability to classify early oral tongue SCCs into low-risk and high-risk categories would represent a major advancement in their management.

Methods

Depth of invasion, tumor budding, histologic risk-assessment score (HRS), and cancer-associated fibroblast (CAF) density were studied in 233 cases of T1/T2 N0M0 oral tongue SCC managed in 5 university hospitals in Finland.

Results

Tumor budding (≥5 clusters at the invasive front of the tumor) and depth of invasion (≥4 mm) were associated with poor prognosis in patients with early oral tongue SCC (hazard ratio [HR], 2.04; 95% confidence interval [CI], 1.17–3.55; HR, 2.55; 95% CI, 1.25–5.20, respectively) after multivariate analysis. The HRS and CAF density did not predict survival. However, high-risk worst pattern of invasion (WPOI), a component of HRS, was also an independent prognostic factor (HR, 4.47; 95% CI, 1.59–12.51).

Conclusion

Analyzing the depth of invasion, tumor budding, and/or WPOI in prognostication and treatment planning of T1/T2 N0M0 oral tongue SCC is recommended.

Prognostic molecular markers in cancer - quo vadis?

Despite the tremendous number of studies of prognostic molecular markers in cancer, only a few such markers have entered clinical practise. The lack of clinical prognostic markers clearly reflects limitations in or an inappropriate approach to prognostic studies. This situation should be of great concern for the research community, clinicians and patients. In the present review, we evaluate immunohistochemical prognostic marker studies in oral squamous cell carcinomas (OSCC) from 2006 to 2012. We comment upon general issues such as study design, assay methods and statistical methods, applicable to prognostic marker studies irrespective of cancer type. The three most frequently studied markers in OSCC are reviewed. Our analysis revealed that most new molecular markers are reported only once. To draw conclusions of clinical relevance based on the few markers that appeared in more than one study was problematic due to between-study heterogeneity. Currently, much valuable tissue material, time and money are wasted on irrelevant studies.

CD271 defines a stem cell-like population in hypopharyngeal cancer

Cancer stem cells contribute to the malignant phenotypes of a variety of cancers, but markers to identify human hypopharyngeal cancer (HPC) stem cells remain poorly understood. Here, we report that the CD271(+) population sorted from xenotransplanted HPCs possesses an enhanced tumor-initiating capability in immunodeficient mice. Tumors generated from the CD271(+) cells contained both CD271(+) and CD271(-) cells, indicating that the population could undergo differentiation. Immunohistological analyses of the tumors revealed that the CD271(+) cells localized to a perivascular niche near CD34(+) vasculature, to invasive fronts, and to the basal layer. In accordance with these characteristics, a stemness marker, Nanog, and matrix metalloproteinases (MMPs), which are implicated in cancer invasion, were significantly up-regulated in the CD271(+) compared to the CD271 (-) cell population. Furthermore, using primary HPC specimens, we demonstrated that high CD271 expression was correlated with a poor prognosis for patients. Taken together, our findings indicate that CD271 is a novel marker for HPC stem-like cells and for HPC prognosis.

Biological and clinical significance of p75NTR expression in laryngeal squamous epithelia and laryngocarcinoma

CONCLUSION

The apparent features of p75 neurotrophin receptor (p75(NTR)) expression indicated that p75(NTR) would serve as a potential stem cell marker for normal human laryngeal squamous epithelia. In human laryngeal squamous cell carcinoma (LSCC) p75(NTR) is differentially expressed. The abnormal expression and distribution of p75(NTR) may indicate malignant transformation.

OBJECTIVE

To investigate the expression of p75(NTR) and its possible roles in normal laryngeal squamous epithelia and LSCC.

METHODS

We used immunohistochemistry methods to examine normal laryngeal epithelia, para-cancer mucosa with dysplasia, laryngeal papilloma, and LSCC specimens for the expression of p75(NTR), nerve growth factor (NGF), -tyrosine kinase receptor (TrkA), p63, and Ki67. Immunocytochemistry and flow cytometry were used to examine the expression of p75(NTR) in Hep-2 cells.

RESULTS

The expression of p75(NTR) was only located in basal cells of normal laryngeal epithelia, consistent with the staining features of epithelial stem cells as evidenced by parallel staining of p63, a putative keratinocyte stem cell marker. p75(NTR) is differentially expressed in LSCC, although no significant relationship was found with many clinicopathologic factors, this expression and distribution may correlate to malignant transformation and tumor proliferation. Co-expression of p75(NTR) and CD133 was confirmed, showing the association of p75(NTR)-positive cells with cancer stem cells in Hep-2 cells.

Gene Expression Signatures of Lymph Node Metastasis in Oral Cancer: Molecular Characteristics and Clinical Significances

Even though lymph node metastasis accounts for the vast majority of cancer death in patients with oral cancer (OC), the molecular mechanisms of lymph node metastasis remain elusive. Genome-wide microarray analyses and functional studies in vitro and in vivo, along with detailed clinical observations, have identified a number of molecules that may contribute to lymph node metastasis. These include lymphangionenic cytokines, cell adhesion molecules, basement membrane-interacting molecules, matrix enzymes and relevant downstream signaling pathways. However, defined gene signatures from different studies are highly variable, which hinders their translation to clinically relevant applications. To date, none of the identified signatures or molecular biomarkers has been successfully implemented as a diagnostic or prognostic tool applicable to routine clinical practice. In this review, we will first introduce the significance of lymph node metastasis in OC, and clinical/experimental evidences that support the underlying molecular mechanisms. We will then provide a comprehensive review and integrative analysis of the existing gene expression studies that aim to identify the metastasis-related signatures in OC. Finally, the remaining challenges will be discussed and our insights on future directions will be provided.

Induction of invasion in an organotypic oral cancer model by CoCl2, a hypoxia mimetic

Invasion is a hallmark of malignancy. The aim of this study was to develop an in vitro model that can be used for experimental studies of cancer cell invasion. The organotypic oral cancer model was constructed by growing oral squamous cell carcinoma (OSCC) cells on a collagen matrix in which normal human fibroblasts were incorporated. Immunohistochemical staining of the model showed that the expression of invasion-related molecules such as phosphorylated extracellular signal-regulated kinases 1 and 2 (p-ERK1/2), cyclooxygenase-2 (COX-2), p75(NTR), and hepatocyte growth factor receptor (Met) was similar to that seen in OSCC. Treatment of the model with cobalt chloride (CoCl(2)) to mimic hypoxic conditions increased cancer cell invasion, defined as the appearance of cancer cell islands protruding into the matrix. Models treated with CoCl(2) showed increased expression of p75(NTR) and laminin-5 in the cancer cells, and a more pronounced fragmentation of collagen IV in the basal membrane area, in contrast to models that were left untreated. The results indicate that the present model is well suited for studies on cancer cell invasion in the matrix and that the addition of CoCl(2) on day 3 of the experiment is indicated because it markedly increases the invasion and improves the model.

Potential biomarkers in saliva for oral squamous cell carcinoma

Sensitive and reliable early diagnostic markers for oral squamous cell carcinoma (OSCC) remain unavailable. Early identification of recurrence for OSCC is also a challenge. Unlike the other deep cancers, OSCC is located in oral cavity. The DNA, RNA, and protein derived from the living cancer cells and inflammatory cells then can be conveniently obtained from saliva. High-throughput genomic and proteomic approaches have been carried out to identify the potential biomarkers in body fluids such as saliva and blood for diagnosis and prognosis of OSCC. This article reviewed the recently identified biomarkers from saliva for OSCC. In addition, the biomarkers which have been correlated with OSCC tumor malignancy by molecular pathology analysis are also described. Finally, the potential biomarkers that have been demonstrated to associate with the malignant OSCC may be used for salivary screening for high-risk patients are suggested. This article may help to identify the potential biomarkers for screening and the molecular pathology analysis for high-risk patients of OSCC. Effective screening to identify high-risk patients can allow the clinician to provide the appropriate treatment without delay and to reduce the recurrence of OSCC.