Molecular mediators of metastasis in head and neck squamous cell carcinoma

Ribosomal Dysregulation in Metastatic Laryngeal Squamous Cell Carcinoma: Proteomic Insights and CX-5461's Therapeutic Promise

One of the main barriers to the successful treatment of laryngeal squamous cell carcinoma (LSCC) is postoperative progression, primarily due to tumor cell metastasis. To systematically investigate the molecular characteristics and potential mechanisms underlying the metastasis in laryngeal cancer, we carried out a TMT-based proteomic analysis of both cancerous and adjacent non-cancerous tissues from 10 LSCC patients with lymph node metastasis (LNM) and 10 without. A total of 5545 proteins were quantified across all samples. We identified 57 proteins that were downregulated in LSCC with LNM, which were enriched in cell adhesion pathways, and 69 upregulated proteins predominantly enriched in protein production pathways. Importantly, our data revealed a strong correlation between increased ribosomal activity and the presence of LNM, as 18 ribosomal subunit proteins were found to be upregulated, with RPS10 and RPL24 being the most significantly overexpressed. The potential of ribosomal proteins, including RPS10 and RPL24, as biomarkers for LSCC with LNM was confirmed in external validation samples (six with LNM and six without LNM) using Western blotting and immunohistochemistry. Furthermore, we have confirmed that the RNA polymerase I inhibitor CX-5461, which impedes ribosome biogenesis in LSCC, also decreases the expression of RPS10, RPL24, and RPS26. In vitro experiments have revealed that CX-5461 moderately reduces cell viability, while it significantly inhibits the invasion and migration of LSCC cells. It can enhance the expression of the epithelial marker CDH1 and suppress the expression of the mesenchymal markers CDH2, VIM, and FN at a dose that does not affect cell viability. Our study broadens the scope of the proteomic data on laryngeal cancer and suggests that ribosome targeting could be a supplementary therapeutic strategy for metastatic LSCC.

Theragnostic Glycol Chitosan-Conjugated Gold Nanoparticles for Photoacoustic Imaging of Regional Lymph Nodes and Delivering Tumor Antigen to Lymph Nodes

Lymph node mapping is important in cancer immunotherapy because the morphology of lymph nodes is one of the crucial evaluation criteria of immune responses. We developed new theragnostic glycol-chitosan-coated gold nanoparticles (GC-AuNPs), which highlighted lymph nodes in ultrasound-guided photoacoustic (US/PA) imaging. Moreover, the ovalbumin epitope was conjugated GC-AuNPs (OVA-GC-AuNPs) for delivering tumor antigen to lymph node resident macrophage. In vitro studies proved the vigorous endocytosis activity of J774A.1 macrophage and consequent strong photoacoustic signals from them. The macrophages also presented a tumor antigen when OVA-GC-AuNPs were used for cellular uptake. After the lingual injection of GC-AuNPs into healthy mice, cervical lymph nodes were visible in a US/PA imaging system with high contrast. Three-dimensional analysis of lymph nodes revealed that the accumulation of GC-AuNPs in the lymph node increased as the post-injection time passed. Histological analysis showed GC-AuNPs or OVA-GC-AuNPs located in subcapsular and medullar sinuses where macrophages are abundant. Our new theragnostic GC-AuNPs present a superior performance in US/PA imaging of lymph nodes without targeting moieties or complex surface modification. Simultaneously, GC-AuNPs were able to deliver tumor antigens to cause macrophages to present the OVA epitope at targeted lymph nodes, which would be valuable for cancer immunotherapy.

Wnt/β-catenin/Slug pathway contributes to tumor invasion and lymph node metastasis in head and neck squamous cell carcinoma

The canonical Wnt/β-catenin pathway is involved in diverse cancer development mechanisms, such as proliferation, migration, and invasion. However, its role in head and neck squamous cell carcinoma (HNSCC) remains largely unknown. We investigated whether the canonical Wnt/β-catenin signaling pathway acts as a controller of invasion and lymph node metastasis (LNM) in HNSCC. Loss of function experiments against the canonical Wnt/β-catenin pathway were conducted to evaluate its invasive and metastatic role in HNSCC cells. Slug was evaluated as a downstream protein in canonical Wnt/β-catenin-mediated invasion. In addition, canonical Wnt/β-catenin and Slug expression levels were examined in 119 HNSCC tissue samples to study the relevance of these proteins in LNM and prognosis of patients post-treatment. In vitro suppression of β-catenin expression led to decreased migration and invasion of HNSCC cells. Using an in vivo mouse orthotopic LNM model, a decrease in LNM was observed with mitigated β-catenin expression. Slug expression upregulation mediates invasion and LNM by the canonical Wnt/β-catenin pathway. Simultaneous expression of β-catenin and Slug is the major predictive factor of LNM and survival rate in patients with HNSCC. In conclusion, the canonical Wnt/β-catenin/Slug signaling axis significantly contributes to cancer cell invasion and LNM. Its blockade may be a treatment strategy for LNM and tumor recurrence in HNSCC.

Assessment and treatment strategies for occult contralateral lymph node metastasis in hypopharyngeal squamous cell carcinoma patients with ipsilateral node-positive necks

Hypopharyngeal squamous cell carcinoma (HSCC) is an aggressive disease with poor prognosis, yet studies have largely been more qualitatively focused. Our study aims to quantitatively predict the risk of occult contralateral lymph node metastasis (cLNM) for HSCC patients with ipsilateral lymph node metastasis (iLNM). This will be based on pre- and post-operative indexes to guide the selection of prophylactic contralateral lymph node dissection (cLND) and postoperative adjuvant treatments. Multivariate analyses of 462 primary HSCC patients with iLNM showed that the age of patients, subregions of tumor, pathological T (pT) stage, ipsiateral MLS and metastatic lymph node number (MLN), and lymph nodal necrosis were independent cLNM risk factors. These were used to construct two nomograms that can effectively predict the contralateral neck involvement in HSCC patients with ipsilateral positive lymph nodes. The first nomogram (pre-model) provides quantitative assessment on the necessity of cLND, while the second nomogram (post-model) informs regions of interest for therapeutic radiation. Overall, patients deemed high-risk of cLNM by pre-model should receive cLND. Post-operation, patients deemed high-risk of cLNM by post-model should receive therapeutic radiation targeting contralateral neck lymph nodes, moderate-risk group warrants comparatively lower dose contralaterally, while low-risk group requires only follow-up.

Clinical-pathological and sociodemographic factors associated with the distant metastasis and overall survival of oral cavity and oropharynx squamous cell carcinoma

BACKGROUND

The objective of this study was to evaluate the influence of clinical-pathological and sociodemographic factors on the prevalence of distant metastasis (DM) and overall survival in patients with oral cavity and oropharynx squamous cell carcinoma (OOSCC).

MATERIAL AND METHODS

Cross-sectional study based on the records of 404 OOSCC patients evaluated for DM, covering the period 2000-2014. We analysed the influence of age, sex, level of schooling, primary tumor subsite, treatment, marital status, family history of cancer, history of smoking and alcohol consumption, type of health care coverage (private vs. public) and overall survival. Findings were submitted to Fisher's exact test, Pearson's chi-squared test, Mantel-Cox log-rank testing and multinomial and Cox regression analysis (SPSS v. 20.0; p<0.05).

RESULTS

The prevalence of DM was 5.4% (22/404). The respiratory tract was the most affected DM site (n=9; 40.9%). Male sex (p=0.049), oropharyngeal primary tumor (p=0.008), stage T3-4 (p=0.022), lymph node metastasis (N+) (p<0.001) and palliative treatment (p=0.005) were directly associated with DM. Patients with oral primary tumours (p=0.343) and primary oropharyngeal tumours (p=0.242) did not differ significantly with regard to the prevalence of DM. N+ was an independent risk factor for DM (p=0.017). Five variables independently reduced overall survival: male sex (p=0.035), age >65 years (p=0.046), indigenous/brown racial type (p=0.045), palliative treatment (p=0.035) and DM (p=0.048).

CONCLUSIONS

Lymph node metastasis independently increased the prevalence of DM and, along with male sex, older age, brown racial type and palliative treatment, was independently associated with poor prognosis in patients with OOSCC.

The presence of risk factors and corresponding treatment strategies post-surgical resection in stage IV hypopharyngeal squamous cell carcinoma patients: a retrospective cohort study

Background

This study aims to explore the adverse features and determine whether adjuvant chemoradiation after surgical resection can benefit stage IV hypopharyngeal squamous cell carcinoma (HSCC) patients.

Methods

We conducted a retrospective review covering 267 patients with stage IV HSCC. Propensity score-matched analysis was employed to reduce selection bias.

Results

T3–T4 or N2c–N3 stage, positive surgical margin, extracapsular spread and lymphovascular invasion were adverse features for overall survival (OS) in stage IV HSCC patients. For patients possessing these adverse features, those who received postoperative adjuvant treatment (PAT) had significantly better OS and recurrence-free survival (RFS) than patients who did not (P value =0.000 and 0.007, respectively). In addition, adjuvant chemoradiation demonstrated better OS and RFS compared to adjuvant radiation (P value =0.030 and 0.017, respectively). However, PAT showed no significant impact on OS and RFS (P value =0.776 and 0.847, respectively) in patients without adverse features.

Conclusions

Adjuvant treatments are recommended for stage IV HSCC patients that possess adverse features of pT3 and pT4 stages, N2c and N3 stages, positive surgical margin, extracapsular spread and lymphovascular invasion. For these patients, postoperative adjuvant chemoradiotherapy (CRT) is preferred. For patients without adverse features, observation and regular re-examination is sufficient post tumour resection.

STAT3 Promotes Invasion and Aerobic Glycolysis of Human Oral Squamous Cell Carcinoma via Inhibiting FoxO1

Signal transducer and activator of transcription 3 (STAT3), a previously accepted tumor-promoting protein in various malignancies, plays a key role in the process of cancer glycolysis. However, the role and potential mechanism of STAT3 in aerobic glycolysis and progression of oral squamous cell carcinoma (OSCC) has not been explored. In the present study, we demonstrated that STAT3 knockdown remarkably inhibited migration, invasion, expressions of epithelial-mesenchymal transition (EMT) markers, and aerobic glycolysis of OSCC cells by up-regulation of FoxO1. Consistently, the expression of nuclear Tyr705-phosphorylated STAT3, an active form of STAT3, was significantly elevated in OSCC tissues compared with adjacent normal tissues, and increased nuclear staining of Tyr705-phosphorylated STAT3 was associated with metastasis and shorter overall survival. Moreover, FoxO1, which was also mainly expressed in OSCC specimens, decreased in poorly-differentiated tissues compared with the relatively well-differentiated ones, and inversely correlated with the expression of nuclear Tyr705-phosphorylated STAT3 from patients with OSCC. Hence, our findings collectively characterized the contributing role of STAT3/FoxO1 in invasion and aerobic glycolysis of OSCC cells, which may lead to the worse clinical outcome.

Identification and validation of potential long non-coding RNA biomarkers in predicting survival of patients with head and neck squamous cell carcinoma

Long non-coding RNAs (lncRNAs) are frequently dysregulated in cancer and their aberrant expression has been associated with cancer diagnosis and prognosis, which suggests that they may be promising molecular biomarkers. However, understanding of the expression pattern of lncRNAs and their prognostic roles in head and neck squamous cell carcinoma (HNSCC) is relatively limited. In the current study, the prognostic value of lncRNA expression profiles in predicting the OS of patients with HNSCC was investigated by integrating clinical and profiling data from The Cancer Genome Atlas. A total of ten lncRNAs closely associated with the prognosis of patients with HNSCC were identified and may serve as novel biomarkers. This 10-lncRNA signature was used to classify patients into 2 groups with significantly different overall survival (OS) times (median OS time, 1.65 vs. 13.04 years; P<0.0001). This lncRNA signature was validated in an independent testing cohort. The results of multivariable Cox regression and stratification analyses revealed that the prognostic value of the 10-lncRNA signature was independent of other clinical and pathological factors for the survival of patients with HNSCC. Functional analysis demonstrated that lncRNA expression-based risk scoring may reflect the basic status of the immune response in the tumor microenvironment. The presented study demonstrated the value of a lncRNA signature as a potential biomarker to improve the clinical prognosis of patients with HNSCC.

A Cost-Effective and Efficient Chick Ex-Ovo CAM Assay Protocol to Assess Angiogenesis

The chick chorioallantoic membrane (CAM) is an extra-embryonic membrane, comprised of a high density of blood and lymphatic vessels. CAM has a dense capillary network and is commonly used to study in vivo angiogenesis and anti-angiogenesis in response to potential biomolecules and drugs. Most of the earlier reported CAM assays described the in-ovo method—where the viability of the embryo is higher, but accessibility to the CAM is limited. Ex-ovo CAM methods were previously described that employed shell-less cultures of chick embryos, but the low viability of embryos reduced the overall robustness of the angiogenesis assays. We described a method (named as cup-CAM method) which is more economical, has better accessibility and has significantly improved the viability of the embryo till advanced developmental stages. We could perform this simple yet useful experimentation with the common tools available in the laboratory. We successfully used the cup-CAM method for showing the paracrine effects of conditioned media from tumor cells, on the angiogenesis. This method can be used to assay the angiogenic potential of a drug or protein and to observe the embryonic development of the chick embryo and other related scientific applications.

CD45RA-Foxp3high regulatory T cells have a negative impact on the clinical outcome of head and neck squamous cell carcinoma

BACKGROUND

Although regulatory T cells (Tregs) are thought to play an important role in immune suppression, their clinical significance in head and neck squamous cell carcinoma (HNSCC) is unclear. A recent study reported Tregs could be divided into functional subsets based on the expression of CD45RA and Foxp3.

METHOD

The frequency of circulating Treg subsets was analyzed in patients with HNSCC and compared with the frequency in patients with benign tumors. The association of Treg subsets with the frequency of lymphocyte subsets, status of progression, clinical course, and prognosis were also examined.

RESULTS

The frequency of CD4+Foxp3+ Tregs was comparable between HNSCC patients and age-matched benign tumor patients; however, CD45RA-Foxp3high Tregs were significantly increased in HNSCC patients, in particular those with advanced stage tumors. The high frequency of CD45RA-Foxp3high Tregs correlated with a poor prognosis and the low frequency of CD45RA-Foxp3high Tregs before treatment showed a better clinical outcome, even in patients with advanced stage tumors. CD45RA-Foxp3high Treg numbers were decreased after intensive treatments; however, Treg numbers recovered in the early stages of recurrent cases, even before the clinical manifestation.

CONCLUSION

CD45RA-Foxp3high Tregs are associated with the clinical course of HNSCC and might be a new target for treatment and an early marker of tumor recurrence in HNSCC patients.

Sensitivity and Specificity of Cetuximab-IRDye800CW to Identify Regional Metastatic Disease in Head and Neck Cancer

Purpose: Comprehensive cervical lymphadenectomy can be associated with significant morbidity and poor quality of life. This study evaluated the sensitivity and specificity of cetuximab-IRDye800CW to identify metastatic disease in patients with head and neck cancer.Experimental Design: Consenting patients scheduled for curative resection were enrolled in a clinical trial to evaluate the safety and specificity of cetuximab-IRDye800CW. Patients (n = 12) received escalating doses of the study drug. Where indicated, cervical lymphadenectomy accompanied primary tumor resection, which occurred 3 to 7 days following intravenous infusion of cetuximab-IRDye800CW. All 471 dissected lymph nodes were imaged with a closed-field, near-infrared imaging device during gross processing of the fresh specimens. Intraoperative imaging of exposed neck levels was performed with an open-field fluorescence imaging device. Blinded assessments of the fluorescence data were compared to histopathology to calculate sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV).Results: Of the 35 nodes diagnosed pathologically positive, 34 were correctly identified with fluorescence imaging, yielding a sensitivity of 97.2%. Of the 435 pathologically negative nodes, 401 were correctly assessed using fluorescence imaging, yielding a specificity of 92.7%. The NPV was determined to be 99.7%, and the PPV was 50.7%. When 37 fluorescently false-positive nodes were sectioned deeper (1 mm) into their respective blocks, metastatic cancer was found in 8.1% of the recut nodal specimens, which altered staging in two of those cases.Conclusions: Fluorescence imaging of lymph nodes after systemic cetuximab-IRDye800CW administration demonstrated high sensitivity and was capable of identifying additional positive nodes on deep sectioning. Clin Cancer Res; 23(16); 4744-52. ©2017 AACR.

Expression of IL-1α correlates with distant metastasis in patients with head and neck squamous cell carcinoma

The presence of IL-1 in human cancers is associated with aggressive tumor biology but its prognostic value is unknown. We studied whether IL-1α expression is a prognostic marker of distant metastasis in patients with head and neck squamous cell carcinoma (HNSCC). IL-1α mRNA and protein levels were determined in tumor samples and cancer cell lines using RT-PCR and ELISA. The effects of constitutive IL-1α expression by tumor lines were characterized. IL-1α mRNA and protein secretion were higher in tumor samples from patients who later developed distant metastasis than in patients who did not. By using distant metastasis as a dependent variable, patients were classified into two categories of IL-1α transcript-levels. The high-IL-1α group had a significantly lower five-year distant metastasis-free survival than the low-IL-1α group [70.0% (CI 95%: 55.9-84.1%) vs 94.7% (CI 95%:90.2-99.2%)]. When IL-1α transcript-levels were combined with clinical factors related to tumor metastasis, the predictive power of the model increased significantly. Additionally, transcript levels of IL-1α correlated significantly with those of the IL-1 family genes and genes related to the metastatic process. IL-1 treatment of microvascular endothelial cells increased adhesion of HNSCC cells but no differences were found based on constitutive IL-1α expression by tumor cells. Nevertheless, IL-1α produced by tumor cells effectively increased their transmigration across the endothelium. We found a significant relationship between IL-1α expression and development of distant metastasis in HNSCC patients. IL-1α expression could help to define a subset of patients at high risk of distant metastasis who could benefit from adjuvant treatment.

Relation between the level of lymph node metastasis and survival in locally advanced head and neck squamous cell carcinoma

BACKGROUND

The current head and neck squamous cell carcinoma (HNSCC) staging system may not capture the full prognostic implications of regional lymph node involvement. This study investigated the impact of the level of lymph node metastasis (LNM) on survival.

METHODS

The Surveillance, Epidemiology, and End Results registry was queried for oral cavity (OC), oropharynx (OP), larynx (LAR), and hypopharynx (HP) HNSCC. A multivariate Cox proportional hazards model was used to evaluate whether the level of LNM was an independent prognostic factor. Site-specific recursive-partitioning analysis was performed to classify patients into different risk groups.

RESULTS

In all, 14,499 patients, including OC (n = 2463), OP (n = 8567), LAR (n = 2332), and HP patients (n = 1137), were analyzed. Both the American Joint Committee on Cancer (AJCC) N classification and the level of LNM showed significant effects on overall survival (OS) in patients with OC, OP, or LAR HNSCC but not in patients with HP HNSCC. In patients with N2 disease, the AJCC subclassification (N2a, N2b, or N2c) was significantly associated with the OS of patients with OP and LAR HNSCC but not with the OS of patients with OC or HP HNSCC, whereas the level of LNM (primary, secondary, or tertiary) was significantly associated with the OS of patients with OC, OP, and LAR HNSCC but not HP HNSCC. With recursive-partitioning analysis, a simple, primary site-specific prognostic tool integrating the AJCC T and N classifications and the level of LNM was designed, and it could be easily used by health care providers in clinic.

CONCLUSIONS

The level of LNM is an independent prognostic factor for patients with locally advanced HNSCC and could add to the prognostic value of AJCC T and N classifications in patients with locally advanced HNSCC.

SOX2 regulates self-renewal and tumorigenicity of stem-like cells of head and neck squamous cell carcinoma

Background:

Head and neck squamous cell carcinomas (HNSCCs) display cellular heterogeneity and contain cancer stem cells (CSCs). Sex-determining region Y [SRY]-box (SOX)2 is an important regulator of embryonic stem cell fate and is aberrantly expressed in several types of human tumours. Nonetheless, the role of SOX2 in HNSCC remains unclear.

Methods:

We created cells ectopically expressing SOX2 from previously established HNSCC cells and examined the cell proliferation, self-renewal capacity, and chemoresistance of these cells compared with control cells. In addition, we knocked down SOX2 in primary spheres obtained from HNSCC tumour tissue and assessed the attenuation of stemness-associated traits in these cells in vitro and in vivo. Furthermore, we examined the clinical relevance of SOX2 expression in HNSCC patients.

Results:

SOX2 is aberrantly expressed in primary tissue of HNSCC patients but not in healthy tissue. SOX2 expression correlated with tumour recurrence and poor prognosis of HNSCC patients. Ectopic expression of SOX2 induced cell proliferation via cyclin B1 expression and stemness-associated features, such as self-renewal and chemoresistance. In addition, a knockdown of SOX2 in HNSCC CSCs attenuated their self-renewal capacity, chemoresistance (through ABCG2 suppression), invasion capacity (via snail downregulation), and in vivo tumorigenicity.

Conclusions:

These results suggest that SOX2 may have important roles in the ‘stemness' and progression of HNSCC. Targeting SOX2-positive tumour cells (CSCs) could be a new therapeutic strategy in HNSCCs.

Tadalafil reduces myeloid-derived suppressor cells and regulatory T cells and promotes tumor immunity in patients with head and neck squamous cell carcinoma

PURPOSE

Myeloid-derived suppressor cells (MDSC) and regulatory T cells (Treg) play a key role in the progression of head and neck squamous cell carcinoma (HNSCC). On the basis of our preclinical data demonstrating that phosphodiesterase-5 (PDE5) inhibition can modulate these cell populations, we evaluated whether the PDE5 inhibitor tadalafil can revert tumor-induced immunosuppression and promote tumor immunity in patients with HNSCC.

EXPERIMENTAL DESIGN

First, we functionally and phenotypically characterized MDSCs in HNSCCs and determined, retrospectively, whether their presence at the tumor site correlates with recurrence. Then, we performed a prospective single-center, double-blinded, randomized, three-arm study in which patients with HNSCC undergoing definitive surgical resection of oral and oropharyngeal tumors were treated with tadalafil 10 mg/day, 20 mg/day, or placebo for at least 20 days preoperatively. Blood and tumor MDSC and Treg presence and CD8(+) T-cell reactivity to tumor antigens were evaluated before and after treatment.

RESULTS

MDSCs were characterized in HNSCC and their intratumoral presence significantly correlates with recurrence. Tadalafil treatment was well tolerated and significantly reduced both MDSCs and Treg concentrations in the blood and in the tumor (P < 0.05). In addition, the concentration of blood CD8(+) T cells reactive to autologous tumor antigens significantly increased after treatment (P < 0.05). Tadalafil immunomodulatory activity was maximized at an intermediate dose but not at higher doses. Mechanistic analysis suggests a possible off-target effect on PDE11 at high dosages that, by increasing intracellular cAMP, may negatively affect antitumor immunity.

CONCLUSIONS

Tadalafil seems to beneficially modulate the tumor micro- and macro-environment in patients with HNSCC by lowering MDSCs and Tregs and increasing tumor-specific CD8(+) T cells in a dose-dependent fashion.

Reduced expression of AMPK-β1 during tumor progression enhances the oncogenic capacity of advanced ovarian cancer

AMP-activated protein kinase (AMPK) is a key energy sensor that is involved in regulating cell metabolism. Our previous study revealed that the subunits of the heterotimeric AMPK enzyme are diversely expressed during ovarian cancer progression. However, the impact of the variable expression of these AMPK subunits in ovarian cancer oncogenesis remains obscure. Here, we provide evidence to show that reduced expression of the AMPK-β1 subunit during tumor progression is associated with the increased oncogenic capacity of advanced ovarian cancer cells. Immunohistochemical analysis revealed that AMPK-β1 levels were reduced in advanced-stage (P = 0.008), high-grade (P = 0.013) and metastatic ovarian cancers (P = 0.008). Intriguingly, down-regulation of AMPK-β1 was progressively reduced from tumor stages 1 to 3 of ovarian cancer. Functionally, enforced expression of AMPK-β1 inhibited ovarian-cancer-cell proliferation, anchorage-independent cell growth, cell migration and invasion. Conversely, depletion of AMPK-β1 by siRNA enhanced the oncogenic capacities of ovarian cancer cells, suggesting that the loss of AMPK-β1 favors the aggressiveness of ovarian cancer. Mechanistically, enforced expression of AMPK-β1 increased AMPK activity, which, in turn, induced cell-cycle arrest via inhibition of AKT/ERK signaling activity as well as impaired cell migration/invasion through the suppression of JNK signaling in ovarian cancer cells. Taken together, these findings suggest that the reduced expression of AMPK-β1 confers lower AMPK activity, which enhances the oncogenic capacity of advanced-stage ovarian cancer.

Overexpression of DDR2 contributes to cell invasion and migration in head and neck squamous cell carcinoma

Background Discoidin domain receptor 2 (DDR2) is a unique receptor tyrosine kinase (RTK) that is activated by fibrillar collagens. Although DDR2 contributes to the metastasis of some tumors, its role in head and neck squamous cell carcinoma (HNSCC) remains unknown. The aim of this study was to investigate the expression level, clinical and pathological significance, and biologic function of DDR2 in HNSCC. Methods Real-time quantitative PCR, western blot, and immunohistochemical staining were employed to assess the expression levels of DDR2 in HNSCC specimens. Adenovirus-mediated overexpression of DDR2 was used to evaluate its consequences on cell proliferation, invasion, migration, and the process of hypoxia-induced epithelial-mesenchymal transition (EMT). Then nude mouse xenograft and tail vein metastasis models were utilized to validate the in vitro results. Results DDR2 was highly expressed in high grade HNSCC tissues and lowly expressed in low grade HNSCC tissues, but absent or rarely expressed in cancer-associated normal tissues. Both the frequency and expression intensity of DDR2 were significantly associated with tumor pathologic stage and lymph node metastasis. In vitro, DDR2 overexpression in HNSCC cells failed to alter cell proliferation but markedly accelerates cell invasion and migration as well as hypoxia-induced EMT. In vivo, elevated expression of DDR2 speeds up the metastasis of HNSCC cells to the lung. Conclusion DDR2 plays an important role in HNSCC metastasis, and might be a promising target for future therapies in this type of cancer.

Matrix metalloproteinase-7 and matrix metalloproteinase-25 in oral tongue squamous cell carcinoma

BACKGROUND

Predicting the clinical course of early-stage oral tongue squamous cell carcinoma (SCC) is challenging. As matrix metalloproteinases (MMPs) are enzymes associated with invasion, metastasis, and poor survival in many cancers, we examined MMP-7 and MMP-25 in oral tongue SCC.

METHODS

We used tissue microarray (TMA) technique and immunohistochemistry to study the expression of MMP-7 and MMP-25 in 73 patients with stage I to II oral tongue SCC and compared their immunoexpressions with clinical data.

RESULTS

Immunohistochemistry revealed MMP-7 and MMP-25 expression in 90% (n = 63 of 70) and 90% (n = 64 of 71) of the tumors, respectively. MMP-7 protein expression was associated with presence of occult cervical metastases (odds ratio [OR], 3.67; p = .013), increased invasion depth (OR, 4.60; p = .005), and higher tumor grade (OR, 3.30; p = .007). MMP-7 expression was predictive for poor outcome (p = .021). Immunostaining of MMP-25 did not correlate with any clinical parameters.

CONCLUSION

We conclude that MMP-7, but not MMP-25, expression may have prognostic significance in early-stage oral tongue SCC.

Temporal characterization of lymphatic metastasis in an orthotopic mouse model of oral cancer

BACKGROUND

The overall mortality rate in cases of head and neck squamous cell carcinoma (HNSCC) has not improved over the past 30 years, mostly because of the high treatment failure rate among patients with regionally metastatic disease. To better understand the pathobiologic processes leading to lymphatic metastasis development, there is an urgent need for relevant animal models.

METHODS

HNSCC cell lines were implanted into the tongues of athymic nude mice. Histology, immunohistochemistry, and ex vivo 2-photon microscopy were used to evaluate tumor progress and spread.

RESULTS

Orthotopic xenografts of different HNSCC cell lines produced distinct patterns of survival, tumor histology, disease progression rate, and lymph node metastasis development. Remarkably, all injected cell types reached the lymph nodes within 24 hours after injection, but not all developed metastasis.

CONCLUSION

This orthotopic xenograft model closely mimics several characteristics of human cancer and could be extremely valuable for translational studies focusing on lymphatic metastasis development and pathobiology.

Wnt5b promotes the cell motility essential for metastasis of oral squamous cell carcinoma through active Cdc42 and RhoA

The activation of Wnt signaling has been reported in many types of squamous cell carcinoma. In this study, using human oral squamous cell carcinoma (OSCC) cells with different metastatic potential, we investigated the involvement of Wnt signaling in metastasis. Further, we aimed to elucidate the characteristic biological features related to high metastatic potential and to identify new target molecules for the suppression of OSCC lymph node metastasis. We compared SAS-Venus (SAS OSCC cells expressing green fluorescent protein) and SAS-LM8, which is a highly metastatic cell line derived from SAS-Venus by in vivo selection. The SAS-LM8 cell line had greater ability of migration and invasion compared to SAS-Venus. Furthermore, a higher number of filopodia-like protrusive structures were produced in SAS-LM8 cells compared to SAS-Venus cells, and the levels of active Cdc42 and active RhoA protein were higher in SAS-LM8 cells compared to SAS-Venus cells. We did not observe any differences in the expression of Wnt/β-catenin target genes between the two cell lines; however, the mRNA levels of Wnt5b were higher in SAS-LM8 cells compared to SAS-Venus cells. To confirm the involvement of Wnt5b in migration in OSCC cells, we examined the effects of the siRNA-mediated knockdown of Wnt5b in SAS-Venus cells and SAS-LM8 cells. The siRNA treatment significantly inhibited migration and the formation of filopodia-like protrusive structures. Conversely, when stimulated with Wnt5b, the migration and formation of filopodia-like protrusions were significantly enhanced and the levels of active Cdc42 and active RhoA proteins were also increased. These results indicate that Wnt5b is involved in the migration ability of OSCC cells through active Cdc42 and RhoA.

TWIST1 is a molecular marker for a poor prognosis in oral cancer and represents a potential therapeutic target

BACKGROUND

Locoregional recurrence and distant metastases are ominous events in patients with advanced oral squamous cell carcinoma (OSCC). The objective of this study was to identify functional biomarkers that are predictive of OSCC progression to metastasis.

METHODS

The expression profile of a network of epithelial-mesenchymal transition (EMT) genes was investigated in a large cohort of patients with progressive OSCC using a complimentary DNA microarray platform coupled to quantitative reverse transcriptase-polymerase chain reaction and immunohistochemical analyses. Therapeutic potential was investigated in vitro and in vivo using an orthotopic mouse model of metastatic OSCC growing in the tongue microenvironment.

RESULTS

Among deregulated EMT genes, the Twist-related protein 1 (TWIST1) transcription factor and several of its regulated genes were significantly overexpressed across advanced stages of OSCC. This result was corroborated by the clinical observation that Twist1 up-regulation predicted the occurrence of lymph node and lung metastases as well as poor patient survival. In support of Twist1 as a driver of OSCC progression, the up-regulation of Twist1 was observed in cells isolated from patients with metastatic OSCC. The inhibition of Twist1 in these metastatic cells induced a potent inhibition of cell invasiveness in vitro as well as progression in vivo.

CONCLUSIONS

The current results provide evidence for the prognostic value and therapeutic potential of a network of Twist genes in patients with advanced OSCC.

Emerging insights into head and neck cancer metastasis

The purpose of this review was to provide biological concepts of head and neck cancer metastasis. To attain this goal, we analyzed peer-reviewed articles related to head and neck cancer metastasis obtained though PubMed and archived articles. Articles related to the biologic principles of head and neck cancer metastasis were reviewed and summarized. As locoregional control has improved for patients with head and neck cancer, rates of distant metastasis have not decreased. As patients live longer, many will die of complications related to the development of disease at sites below the clavicles. Emerging evidence now suggests a more complicated framework of metastatic behavior for head and neck cancer. Here, we review the role of regional lymph nodes in containing advanced head and neck cancer, evidence for active as opposed to passive tumor cell metastasis, and clinical implications these concepts have on both treatment of head and neck cancer and future research.

Matrix metalloproteinase-13 (MMP-13) directly and indirectly promotes tumor angiogenesis

Matrix metalloproteinases (MMPs) are extracellular zinc-dependent endopeptidases involved in the degradation and remodeling of extracellular matrix in physiological and pathological processes. MMPs also have a role in cell proliferation, migration, differentiation, angiogenesis, and apoptosis. We previously identified cancer invasion-related factors by comparing the gene expression profiles between parent and the highly invasive clone of cancer cells. Matrix metalloproteinase-13 (MMP-13) was identified as a common up-regulated gene by cancer invasion-related factors. Although MMP-13 slightly promoted tumor invasion, we found that MMP-13 was involved in tumor angiogenesis. Conditioned medium from MMP-13-overexpressing cells promoted capillary formation of immortalized human umbilical vein endothelial cells. Furthermore, treatment with recombinant MMP-13 protein enhanced capillary tube formation both in vitro and in vivo. MMP-13-promoted capillary tube formation was mediated by activation of focal adhesion kinase and ERK. Interestingly, MMP-13 promoted the secretion of VEGF-A from fibroblasts and endothelial cells. By immunohistochemical analysis, we found a possible correlation between MMP-13 expression and the number of blood vessels in human cancer cases. In summary, these findings suggest that MMP-13 may directly and indirectly promote tumor angiogenesis.

Molecular changes in the multistage pathogenesis of head and neck cancer

Head and neck squamous cell carcinomas (SCCHN) arise in the mucosa of the upper aerodigestive tract at multiple anatomic sites. While tobacco and alcohol exposure remain the primary risk factors for this malignancy, infection with the human papilloma virus is emerging as a major contributing factor to cancers that arise primarily in the oropharynx. Despite therapeutic advances, survival has remained relatively unchanged over the past few decades. Increased understand of the cellular and molecular biology of these cancers will improve our understanding of this malignancy and facilitate the development of more effective therapeutic strategies. Alterations that have been studied to date include genetic and epigenetic changes. While the epidermal growth factor receptor (EGFR) is the only established molecular therapeutic target, other proteins and pathways are under active investigation to determine their contribution to SCCHN carcinogenesis and progression.

Alteration of G1/S transition regulators influences recurrences in head and neck squamous carcinomas

Head-Neck Squamous Cell Carcinoma (HN-SCC) is a clinically challenging disease associated with a high mortality rate. The chemo-radiotherapy treatments that aim to preserve the organ represent the current gold standard therapy for advanced laryngeal disease, reserving surgery only for non-responsive or relapsed cases. Despite these aggressive approaches, local persistent or recurrent disease remains the primary cause of treatment failure but we still do not have known factors and/or markers able to predict the outcome of the disease and in particular the risk of local relapse. Here we address this point on a series of 54 cases of HN-SCC for whom the presence of local relapse was known. Using immunohistochemistry (IHC) analysis to evaluate protein expression and localization in the recurrence free and recurrence positive samples, we studied the expression of key cell cycle regulators including p53, p16, p27, pRB, Cyclin D1, Cyclin D3, and Stathmin. Overall by analyzing seven different cell cycle regulators we can hypothesize that the alteration of G1/S regulation represents a fundamental event in the onset/progression of HN-SCC cancers and that the associate use of Cyclin D1/p16 expression should be considered as a possible biomarker toward the identification of those patients that will probably develop a recurrent disease and thus should benefit of a more aggressive treatment.

MMP-10/stromelysin-2 promotes invasion of head and neck cancer

Background

Periostin, IFN-induced transmembrane protein 1 (IFITM1) and Wingless-type MMTV integration site family, member 5B (Wnt-5b) were previously identified as the invasion promoted genes of head and neck squamous cell carcinoma (HNSCC) by comparing the gene expression profiles between parent and a highly invasive clone. We have previously reported that Periostin and IFITM1 promoted the invasion of HNSCC cells. Here we demonstrated that Wnt-5b overexpression promoted the invasion of HNSCC cells. Moreover, stromelysin-2 (matrix metalloproteinase-10; MMP-10) was identified as a common up-regulated gene among Periostin, IFITM1 and Wnt-5b overexpressing HNSCC cells by using microarray data sets. In this study, we investigated the roles of MMP-10 in the invasion of HNSCC.

Methods and Findings

We examined the expression of MMP-10 in HNSCC cases by immunohistochemistry. High expression of MMP-10 was frequently observed and was significantly correlated with the invasiveness and metastasis in HNSCC cases. Next, we examined the roles of MMP-10 in the invasion of HNSCC cells in vitro. Ectopic overexpression of MMP-10 promoted the invasion of HNSCC cells, and knockdown of MMP-10 suppressed the invasion of HNSCC cells. Moreover, MMP-10 knockdown suppressed Periostin and Wnt-5b-promoted invasion. Interestingly, MMP-10 overexpression induced the decreased p38 activity and MMP-10 knockdown induced the increased p38 activity. In addition, treatment with a p38 inhibitor SB203580 in HNSCC cells inhibited the invasion.

Conclusions

These results suggest that MMP-10 plays an important role in the invasion and metastasis of HNSCC, and that invasion driven by MMP-10 is partially associated with p38 MAPK inhibition. We suggest that MMP-10 can be used as a marker for prediction of metastasis in HNSCC.

Relationship between epidermal growth factor receptor gene copy number and protein expression in oral cavity squamous cell carcinoma

This study was designed to explore the relationship between epidermal growth factor receptor (EGFR) copy number and EGFR protein expression in oral cavity squamous cell carcinoma (OSCCs) in Taiwan. A total of 160 oral cavity squamous cell carcinomas were examined for EGFR protein overexpression using immunohistochemistry and for copy number using a fluorescence in situ hybridization (FISH) assay. Overexpression and increased gene copy numbers of EGFR were found in 75 (46.88%) and 50 (31.25%) cases, respectively. The concordance rate for EGFR gene amplification and protein overexpression was 100%. EGFR overexpression was associated with a poor prognosis both in terms of disease-free survival (DFS) and overall survival (OS). On the other hand, the association between an increase in EGFR gene copies and DFS or OS was insignificant. This was despite the observed significant associations between gene copy number and tumor stage, depth of tumor invasion, lymph node metastasis, bone invasion and perineural invasion. EGFR protein overexpression is closely related to EGFR copy number. Standard methodological and interpretation criteria need to be established that allows EGFR copy number combined with EGFR protein expression to be determined in a manner that allows individualized EGFR targeted therapy in OSCC patients.

Genetic model of transformation and neoplastic progression in laryngeal epithelium

BACKGROUND

The aim of this study was to analyze genetic alterations in the transformation-progression model of laryngeal tumors.

METHODS

Copy number changes of 37 genes were analyzed by multiple ligation-dependent probe amplification (MLPA) in 94 tissue samples.

RESULTS

In the smoker normal mucosa group TP53 loss was predominant, whereas in the precursor lesions CDKN2A loss and CDKN2D gain were most frequent. Precursor lesions with progression presented CTNNB1 loss. In the carcinoma group the most common changes were CDKN2A, MLH1, CTNNB1, and CASP6 losses and RECQL4, CCND1, and EMS1 gains. Positive lymph node primary tumors were related to TP53, IL1A, and RB1 losses and STK11 gain. The lymph node metastases differed from their corresponding primary tumor in LMNA, RECQL4, and IGF1R losses, and N33 and CDKN2D gains.

CONCLUSIONS

Genetic changes and new key genes were found to be associated with specific steps. We included new steps, not presented in the classic models: normal mucosa tobacco exposed, positive lymph node primary tumor, and corresponding lymph node metastases.

Gene therapy for head and neck squamous cell carcinoma using KITENIN (KAI1 COOH-Terminal Interacting Tetraspanin)-antisense therapy

PURPOSE

KAI1 COOH-terminal interacting tetraspanin (KITENIN) has been found to act as a promoter of metastasis in murine models of colon cancer and squamous cell carcinoma (SCC). The suppression of tumor progression and metastasis of established colon cancer in mice was observed after intravenous delivery of small interfering RNA (siRNA) targeting KITENIN. The purpose of this study was to investigate the efficacy of gene therapy targeting KITENIN in human head and neck SCC.

MATERIALS AND METHODS

SNU-1041, a well-established human hypopharyngeal SCC cell line, was used. KITENIN expression in SNU-1041 was measured by Western blot analysis. The cells were prepared, maintained in culture dishes with media, and divided into two groups: the si-KITENIN group and the scrambled group (control). The siRNA targeting KITENIN (si-KITENIN) and scrambled DNA were transfected into the SNU-1041 cells in each group. The effect of gene therapy was compared by in vitro experiments to evaluate invasion, migration, and proliferation.

RESULTS

KITENIN was strongly expressed in the SNU-1041 cells, and the number of invaded cells was reduced more in the si-KITENIN group than in the scrambled group (p<0.001). The speed for the narrowing gap, made through adherent cells, was lower in the si-KITENIN group (p<0.001), and the number of viable proliferating cells was reduced in the si-KITENIN group compared to the scrambled group (p<0.001, the third day). KITENIN protein expression was no longer identified in the si-KITENIN group.

CONCLUSION

Gene therapy using an anti-KITENIN strategy might be effective for head and neck squamous carcinoma.

Functional microarray analysis suggests repressed cell-cell signaling and cell survival-related modules inhibit progression of head and neck squamous cell carcinoma

Background

Cancer shows a great diversity in its clinical behavior which cannot be easily predicted using the currently available clinical or pathological markers. The identification of pathways associated with lymph node metastasis (N+) and recurrent head and neck squamous cell carcinoma (HNSCC) may increase our understanding of the complex biology of this disease.

Methods

Tumor samples were obtained from untreated HNSCC patients undergoing surgery. Patients were classified according to pathologic lymph node status (positive or negative) or tumor recurrence (recurrent or non-recurrent tumor) after treatment (surgery with neck dissection followed by radiotherapy). Using microarray gene expression, we screened tumor samples according to modules comprised by genes in the same pathway or functional category.

Results

The most frequent alterations were the repression of modules in negative lymph node (N0) and in non-recurrent tumors rather than induction of modules in N+ or in recurrent tumors. N0 tumors showed repression of modules that contain cell survival genes and in non-recurrent tumors cell-cell signaling and extracellular region modules were repressed.

Conclusions

The repression of modules that contain cell survival genes in N0 tumors reinforces the important role that apoptosis plays in the regulation of metastasis. In addition, because tumor samples used here were not microdissected, tumor gene expression data are represented together with the stroma, which may reveal signaling between the microenvironment and tumor cells. For instance, in non-recurrent tumors, extracellular region module was repressed, indicating that the stroma and tumor cells may have fewer interactions, which disable metastasis development. Finally, the genes highlighted in our analysis can be implicated in more than one pathway or characteristic, suggesting that therapeutic approaches to prevent tumor progression should target more than one gene or pathway, specially apoptosis and interactions between tumor cells and the stroma.

Clinical, pathological and molecular determinants in squamous cell carcinoma of the oral cavity

Squamous cell carcinoma of the oral cavity (OCSCC) is the most frequently observed form of head-and-neck cancer in Southeast Asia and is the sixth most common cancer worldwide. Most cases of this preventable disease are caused by alcohol consumption, smoking and betel nut chewing. The survival rates of patients with advanced OCSCC have not increased significantly in recent years. While treatments for OCSCC are similar worldwide, survival rates differ by geographical area. The various genetic profiles and individual genetic susceptibility for carcinogens may account for this discrepancy. In some respects, molecular alteration or accumulation affects tumor progression and the clinical outcomes among patients with OCSCC. Clarifying the tumor behavior of oral cancer, with regard to pathological features or molecular aspects, could help clinicians to judge, tailor and adopt more effective therapeutic strategies to treat oral cancer.

KAI1 COOH-terminal interacting tetraspanin (KITENIN) expression in early and advanced laryngeal cancer

OBJECTIVES/HYPOTHESIS

To investigate the expression of KAI1 COOH-terminal interacting tetraspanin (KITENIN) in patients with laryngeal cancers and to examine the correlation between its expression and various clinical and pathological variables.

STUDY DESIGN

Cross-sectional study with planned data collection.

METHODS

Tumor specimens were collected from 32 patients with laryngeal squamous carcinoma (collection of consecutive 32 tumor samples; 14 early stage, 18 advanced stage). Expression of KITENIN in the tissues obtained was determined by Western blot analysis and immunohistochemical staining. The patient characteristics including age, gender, tumor location, histology, stage, tumor extent, lymph node metastasis, and survival were obtained by review of the hospital records.

RESULTS

KITENIN expression was significantly increased in laryngeal cancer tissues compared to adjacent normal tissue mucosa, as well as in metastatic lymph nodes compared to nonmetastatic lymph nodes. High KITENIN expression was significantly associated with advanced stage, tumor extent, and lymph node metastasis (P = .016, .016, and .005, respectively). There was no difference in the overall survival and disease-free survival between the low- and high-KITENIN expression groups among patients with laryngeal cancer.

CONCLUSIONS

These results suggest that KITENIN expression may be associated with tumor progression in patients with laryngeal cancer. Further studies are needed to determine whether KITENIN expression adds prognostic value to conventional factors, such as the stage and status of metastasis, in a large series with a long period of follow-up.

KITENIN represents a more aggressive phenotype in a murine model of oral cavity squamous carcinoma

Objective: To investigate the tumor invasiveness and early lung metastasis associated with KITENIN in a murine model of oral cavity squamous carcinoma.

Study Design: Cross-sectional study with planned data collection.

Setting: Department of Otolaryngology–Head and Neck Surgery, Medical Research Center for Gene Regulation, and Pathology, Chonnam National University Medical School and Hwasun Hospital.

Subjects and Methods: The cDNA of KITENIN and vector only were transfected into the SCC VII (murine squamous cell line) cells. The suspension of 5 × 105/mL viable KITENIN- or vector-transfected SCC VII cells was injected into the floor of the mouth of C3H/HeJ syngeneic mice, deep into the mylohyoid muscle via the intraoral approach. From the first to the sixth week after injection, tumor, lung, liver, and brain tissues were obtained.

Results: For all groups, the tumor invaded the superficial musculature of the floor of the mouth, the deep musculature of the floor of the mouth, the salivary glands, perineural tissue, bone, and skin, sequentially. Lung metastases developed multiple focal nodular patterns at first and then became more extensive. Earlier and more aggressive tumor invasion into the deep floor of the mouth musculature, salivary glands, perineural tissue, bone, and skin was observed in the KITENIN-transfected group compared to the vector-only group. An earlier and more extensive lung metastasis was observed in the KITENIN group.

Conclusion: An antisense KITENIN strategy might inhibit distant metastasis and the progression of head and neck squamous cell carcinoma.

Integration of biomarkers including molecular targeted therapies in head and neck cancer

Head and neck tumors comprise a wide spectrum of heterogeneous neoplasms for which biomarkers are needed to aid in earlier diagnosis, risk assessment and therapy response. The search for biomarkers includes evaluation of tumor tissues and surrogate materials by molecular, genomic and phenotypic means. Ideal biomarkers should be accurate and easy to perform, highly specific, objective, quantitative, and cost effective. Because of the heterogeneity of head and neck tumors, the integration of multiple selected markers in association with the histopathologic features is advocated for risk assessment. For targeted therapy, however, a single key molecule must be identified. Key molecules and pathways for targeted therapy include growth factor receptors, MAPk/ERk pathway, angiogenesis, and epithelial to mesenchymal transition. Over-expression and mutations of genes in these pathways including EGFR, VEGF, HER2, BRAF and RET, contribute to tumorigenesis in head and neck cancers from squamous carcinomas, to salivary adenocarcinomas and thyroid carcinomas, both follicular and c-cell derived. Monoclonal antibodies to the EGFR receptor and oral tyrosine kinase inhibitors are currently being studied in multiple phase II and III clinical trials to determine their efficacy in head and neck cancers and correlative studies for biomarkers are on-going.

Bmi-1 expression predicts prognosis in squamous cell carcinoma of the tongue

BACKGROUND

The prognosis of squamous cell carcinoma of the oral tongue is poor and it would be beneficial to find prognostic markers to better adjust treatment. Bmi-1 controls cell cycle and self-renewal of tissue stem cells, transcription factor c-myc affects cell proliferation and apoptosis, and Snail regulates epithelial-mesenchymal transition. The expression of these markers has been connected to prognosis in many cancer types.

METHODS

Bmi-1, c-myc, and Snail expressions were studied in our material consisting of 73 primarily T1N0M0 oral tongue carcinoma patients. We compared the immunoexpressions of Bmi-1, c-myc, and Snail with clinical parameters including the degree of histological differentiation, tumour size, TNM classification, depth of invasion, and resection margins. In addition, survival analyses were performed, comparing disease-free survival time with the registered protein expression of the markers mentioned above.

RESULTS

A significant correlation between Bmi-1 protein expression and recurrence (log-rank test, P=0.005) was detected. Snail and c-myc expression did not correlate with prognosis. Snail expression correlated with histopathological grade (Fisher's exact test, P=0.007) and with the invasion depth of tumours (chi(2)-test, P=0.037).

CONCLUSION

Negative Bmi-1 immunoexpression might serve as a marker of poor prognosis in oral tongue carcinoma patients.

Genomic instability and tumor-specific DNA alterations in oral leukoplakias

Leukoplakias, clinically identifiable premalignant lesions, often precede oral squamous cell carcinoma (OSCC). Identification of leukoplakias that have the potential for transformation to malignancy is a key clinical problem. The aim of this study was to assess genomic instability, and to detect tumor-specific genomic alterations, in leukoplakias. Genomic instability was analyzed by comparing the DNA fingerprints of 32 leukoplakias with those of paired normal tissue. In addition, the mutational status of the p53 gene was analyzed using polymerase chain reaction-single-stranded conformational polymorphism (PCR-SSCP) and polymerase chain reaction-heteroduplex DNA (PCR-HET), and the mutations were subsequently confirmed by DNA sequencing. Moderate-to-significant genomic instability was detected in all leukoplakias analysed. Nine unique amplicons, present in leukoplakias but not in normal tissue, were retrieved and successfully characterized. The p53 gene was mutated in 40.6% of patients. Four patients with moderate instability and mutated p53 developed OSCC. The data obtained in this study support and concretize the thesis that premalignant lesions possess many of the alterations found in cancer before the development of a malignant phenotype. Inactivation or mutation of the p53 tumor-suppressor might be an early event contributing to genomic instability and increasing the risk of malignant transformation.

Comparison of radiosensitizing effects of the mammalian target of rapamycin inhibitor CCI-779 to cisplatin in experimental models of head and neck squamous cell carcinoma

To determine if the mammalian target of rapamycin (mTOR) inhibitor CCI-779 can sensitize head and neck squamous cell carcinoma (HNSCC) to radiotherapy (XRT) and compare the radiosensitizing effects to cisplatin with its known considerable toxicity. Radiosensitizing effects of CCI-779 were assayed on HNSCC cell lines in vitro. CCI-779 (5 mg/kg), cisplatin (1 mg/kg), and XRT (2 Gy) alone and in combination were evaluated for antitumor activity in mice bearing FaDu and SCC40 xenografts. Effects of CCI-779 on radiation-induced activation of the Akt/mTOR pathway were analyzed. Although CCI-779 did not sensitize HNSCC cells to ionizing radiation in vitro, combination of CCI-779 and XRT significantly augmented the in vivo tumor growth-inhibitory effects of XRT and CCI-779 (P < 0.05). In addition, CCI-779 + XRT suppressed tumor growth more effectively than cisplatin + XRT (P < 0.05). CCI-779 + XRT significantly improved survival compared with XRT alone in both cisplatin-sensitive FaDu (P < 0.01) and cisplatin-resistant SCC40 (P < 0.05) xenograft mice. There were no additional benefits of adding cisplatin to CCI-779 + XRT. CCI-779 significantly attenuated irradiation-induced up-regulation of the mTOR pathway, increased apoptosis and displayed potent antiangiogenic activity in FaDu xenografts that was further enhanced by its combination with XRT (P < 0.05), which may explain the mechanism of its selective radiosensitizing effects in vivo and not in vitro. Antitumor activity of XRT was enhanced when combined with CCI-779 in HNSCC xenograft model. CCI-779 + XRT showed antitumor activity superior to conventional chemoradiotherapy with cisplatin. These results pave the way for clinical trials using molecular targeted therapy with CCI-779 in combination with XRT for HNSCC treatment.

G(alpha)12-mediated pathway promotes invasiveness of nasopharyngeal carcinoma by modulating actin cytoskeleton reorganization

The molecular mechanisms behind the aggressiveness of nasopharyngeal carcinoma (NPC), a highly invasive and metastatic head and neck malignancy, have not been made clear. In this study investigating these mechanisms, guanine nucleotide-binding protein alpha(12) subunit (G(alpha)(12)) signaling was found by microarray analysis to be increased in primary NPC cells and NPC-derived cell lines. Using small interfering RNA to knock down G(alpha)(12) in NPC cells resulted in a reduction in cell migration and invasion as well as a reversal in fibroblastoid morphology. Using microarray analysis, we also found a reduction in expression of key actin dynamics regulators and several epithelial-to-mesenchymal transition-related genes in G(alpha)(12)-depleted NPC cells. Knocking down one of those genes, IQ motif containing GTPase activating protein 1, reduced the migration and formation of adherens junctions and reversed the fibroblastoid morphology of NPC cells, as knocking down G(alpha)(12) was found to do. Immunohistochemical analysis found NPC tumors to have significantly greater levels of G(alpha)(12) protein than the normal basal epithelial cells. Quantitative real-time PCR analysis revealed a significant correlation between G(alpha)(12) mRNA levels and NPC lymph node metastasis. Together, our findings support a model in which activation of G(alpha)(12) signaling promotes tumorigenesis and progression of NPC by modulating actin cytoskeleton reorganization and expression of epithelial-to-mesenchymal transition-related genes. =

KITENIN increases invasion and migration of mouse squamous cancer cells and promotes pulmonary metastasis in a mouse squamous tumor model

KAI1 C-terminal interacting tetraspanin (KITENIN) is reported to promote metastasis in mouse colon cancer models. We investigated the role of KITENIN on the progression of squamous cell carcinoma (SCC). In a preliminary clinical study using resected tissues from head and neck SCC patients, KITENIN was highly expressed in tumors and metastatic lymph nodes, while KAI1 was more increased in adjacent mucosa than in tumor. KITENIN-transfected mouse squamous cancer (SCC VII/KITENIN) cells showed significantly higher invasion, migration, and proliferation than empty vector-transfected cells. In syngeneic mouse squamous tumor models, more increased tumor volume and enhanced lung metastasis were found in SCC VII/KITENIN cells-injected mice. Thus, KITENIN increases invasion and migration of squamous cancer cells and thereby promotes distant metastasis in mouse squamous tumor models.

Overexpression of cortactin in head and neck squamous cell carcinomas can be uncoupled from augmented EGF receptor expression

BACKGROUND

The gene encoding cortactin, CTTN (locus 11q13), an actin-binding substrate of Src kinases, is frequently amplified in breast and head and neck squamous cell carcinomas (HNSCC) and cortactin overexpression is thought to contribute in a significant way to the invasive phenotype of these tumors. Elevated Epidermal Growth Factor receptor (EGFR) expression is also commonly observed in HNSCC and has been associated with poor prognosis and resistance to cytotoxic agents, including ionizing radiation. It has been suggested that cortactin overexpression may increase EGFR levels in these tumors by affecting receptor downregulation, however we recently found by multivariate analysis, that cortactin expression status remained an independent prognostic factor for local recurrence, disease-free survival, and overall survival.

MATERIAL AND METHODS

To examine the potential link between cortactin overexpression and EGFR status, we compared cortactin and EGFR levels in a series of tumor lines derived from HNSCC. RNAi-mediated silencing was performed in cortactin overexpressing cells and in vivo tumoral potential with respect to cortactin and EGFR status was analyzed.

RESULTS AND DISCUSSION

Cortactin and EGFR levels were not strictly coupled in these lines and cortactin depletion did not decrease steady state receptor levels, although it did affect the epithelial to mesenchymal phenotypic conversion of cells. These results, together with clinical findings point to the existence of an EGFR-independent role of cortactin in HNSCC that may have important implications regarding the design of targeted therapies to combat tumor spread.

Molecular pathogenesis of head and neck cancers

Head and neck cancers represent a progressive genetic malady, with genetic aberrations accumulating in response to carcinogen exposure. Although individual genomic aberrations develop at specific time points in the progression axis, the precise role of these abnormalities in tumor progression and cancer behavior remain to be elucidated. This article will give an overview of the current knowledge on the molecular basis for the development of head and neck cancers.

Immunohistochemical analysis of phosphotyrosine signal transducer and activator of transcription 3 and epidermal growth factor receptor autocrine signaling pathways in head and neck cancers and metastatic lymph nodes

PURPOSE

To determine the effect of tyrosine-phosphorylated signal transducer and activator of transcription 3 (pSTAT3) immunoexpression on survival in two independent cohorts of patients with squamous cell carcinoma of the head and neck (SCCHN) and to evaluate pSTAT3, transforming growth factor-alpha (TGF-alpha), epidermal growth factor receptor (EGFR), and gastrin-releasing peptide receptor (GRPR) expression in matched tumor and lymph node metastases in one of these cohorts. EXPERIMENTAL TECHNIQUE: Immunostaining for pSTAT3, TGF-alpha, EGFR, and GRPR was done in two SCCHN cohorts (cohort 1, 61 tumors; cohort 2, 69 paired primary tumors and lymph node metastases). Semiquantitative scores derived from the product of staining intensity (scale 0-3) score and percentage of positive tumor cells were correlated with clinical outcome.

RESULTS

Immunoexpression of pSTAT3 did not correlate with clinical outcome in either cohort (cohort 1, P = 0.914; cohort 2, P = 0.312). In cohort 2, TGF-alpha and EGFR expression in the primary tumors showed some association with decreased disease-free survival (P = 0.0306 and P = 0.0985, respectively). Both pSTAT3 and EGFR showed a correlation of expression between tumor and matched lymph node metastasis (P < 0.0001 and P = 0.0046, respectively). In addition, the expression of EGFR and GRPR in the primary tumors correlated with TGF-alpha expression in paired nodal metastases (P = 0.0043 and P = 0.0268, respectively). In the nodal metastases, TGF-alpha expression correlated with EGFR expression (P = 0.0069). In primary tumors, GRPR expression correlated with TGF-alpha and EGFR expression (P = 0.0378 and P = 0.0026, respectively).

CONCLUSIONS

These findings support an autocrine signaling pathway involving TGF-alpha, EGFR, and pSTAT3 in metastatic SCCHN as well as transactivation of EGFR by GRPR via TGF-alpha, but fails to identify an independent prognostic role for pSTAT3 immunoexpression.

Cortactin overexpression regulates actin-related protein 2/3 complex activity, motility, and invasion in carcinomas with chromosome 11q13 amplification

Carcinoma cell motility and invasion are prerequisites for tumor cell metastasis, which requires regulation of the actin cytoskeleton. Cortactin is an actin-related protein 2/3 (Arp2/3) complex-activating and filamentous (F)-actin-binding protein that is implicated in tumor cell motility and metastasis, partially by its ability to become tyrosine phosphorylated. Cortactin is encoded by the CTTN gene and maps to chromosome 11q13, a region amplified in many carcinomas, including head and neck squamous cell carcinoma (HNSCC). CTTN gene amplification is associated with lymph node metastasis and poor patient outcome, and cortactin overexpression enhances motility in tumor cells lacking 11q13 amplification. However, a direct link between increased motility and invasion has not been reported in tumor cells with chromosome 11q13 amplification and cortactin overexpression. In this study, we have examined the relationship between CTTN amplification and tumor cell motility in HNSCC. In 11 of 39 (28%) HNSCC cases, cortactin overexpression determined by immunohistochemistry correlates with lymph node metastasis and CTTN gene amplification. HNSCC cells containing cortactin gene amplification and protein overexpression display increased binding and activation of Arp2/3 complex, and were more motile and invasive than HNSCC cells lacking CTTN amplification. Down-regulation of cortactin expression in CTTN-amplified HNSCC cells by small interfering RNA impairs HNSCC motility and invasion. Treatment of HNSCC cells with the epidermal growth factor receptor inhibitor gefitinib inhibits HNSCC motility and down-regulates cortactin tyrosine phosphorylation. These data suggest that cortactin may be a valid prognostic and therapeutic marker for invasive and metastatic HNSCC and other carcinomas with 11q13 amplification.

P53 expression in squamous cell carcinomas of the supraglottic larynx and its lymph node metastases: new results for an old question

BACKGROUND

Although p53 overexpression is frequent in head and neck squamous cell carcinomas (HNSCCs), controversy remains regarding the prognostic significance of that overexpression. The objective of this study was to investigate the expression pattern and prognostic significance of p53 expression in HNSCC of the same location, treated in the same way, and with long-term follow-up.

METHODS

P53 expression was determined by immunohistochemistry in paraffin-embedded tissue specimens from 107 consecutive patients (107 primary squamous cell carcinomas of the supraglottic larynx and 46 matched lymph node metastases). All patients underwent surgical resection and bilateral neck dissection.

RESULTS

A strong correlation was observed between p53 expression in the primary tumor and in the matched lymph node metastases (P=.0001). P53 overexpression in the lymph nodes was an independent predictor of regional recurrence (P=.027). Likewise, expression of p53 in the lymph nodes correlated significantly with disease-specific survival (P=.018). Five years after treatment, 70% of patients with p53-negative, metastatic lymph nodes remained alive, whereas only 30% of patients with p53-positive lymph nodes remained alive. In multivariate analysis, lymph node status and p53 expression in the lymph nodes remained associated with survival.

CONCLUSIONS

The current data suggested that, although p53 overexpression is common in supraglottic carcinomas, its expression in the primary tumor is of limited clinical significance. However, the results supported the role of p53 in the lymph node metastases as an independent predictor of regional failure and a poor prognosis in patients with HNSCC. A prospective trial is indicated to validate these findings.

Analysis of a novel human gene, LOC92912, over-expressed in hypopharyngeal tumours

We have identified by differential display a number of novel genes that are expressed in hypopharyngeal head and neck squamous cell carcinoma. We report here the characterisation of one of these novel human genes, LOC92912, that encodes a protein of 375 amino acids. The protein contains a RWD domain, a coiled-coil, and an E2 ubiquitin conjugating enzyme domain. LOC92912 is upregulated in about 85% of tumour samples. It is expressed in tumour masses and in invasive epithelium, and is located in the cytoplasm of cells. To gain insights into its functions, we identified potential interacting partners by immunoaffinity purification of the flag tagged protein followed by MALDI peptide mass fingerprinting mass spectrometry. Actin and six actin-binding proteins were unambiguously identified as potential interacting partners, suggesting that LOC92912's functions may be linked with the cytoskeleton. This novel human gene may represent a new target for cancer therapeutics.