Differential gene expression signature between primary and metastatic head and neck squamous cell carcinoma

Multidimensional outlook on the pathophysiology of cervical cancer invasion and metastasis

Cervical cancer being one of the primary causes of high mortality rates among women is an area of concern, especially with ineffective treatment strategies. Extensive studies are carried out to understand various aspects of cervical cancer initiation, development and progression; however, invasive cervical squamous cell carcinoma has poor outcomes. Moreover, the advanced stages of cervical cancer may involve lymphatic circulation with a high risk of tumor recurrence at distant metastatic sites. Dysregulation of the cervical microbiome by human papillomavirus (HPV) together with immune response modulation and the occurrence of novel mutations that trigger genomic instability causes malignant transformation at the cervix. In this review, we focus on the major risk factors as well as the functionally altered signaling pathways promoting the transformation of cervical intraepithelial neoplasia into invasive squamous cell carcinoma. We further elucidate genetic and epigenetic variations to highlight the complexity of causal factors of cervical cancer as well as the metastatic potential due to the changes in immune response, epigenetic regulation, DNA repair capacity, and cell cycle progression. Our bioinformatics analysis on metastatic and non-metastatic cervical cancer datasets identified various significantly and differentially expressed genes as well as the downregulation of potential tumor suppressor microRNA miR-28-5p. Thus, a comprehensive understanding of the genomic landscape in invasive and metastatic cervical cancer will help in stratifying the patient groups and designing potential therapeutic strategies.

The Promise of Circulating Tumor DNA in Head and Neck Cancer

As the seventh most common cancer globally, head and neck cancers (HNC) exert considerable disease burden, with an estimated 277,597 deaths worldwide in 2020 alone. Traditional risk factors for HNC include tobacco, alcohol, and betel nut; more recently, human papillomavirus has emerged as a distinct driver of disease. Currently, limitations of cancer screening and surveillance methods often lead to identifying HNC in more advanced stages, with associated poor outcomes. Liquid biopsies, in particular circulating tumor DNA (ctDNA), offer the potential for enhancing screening, early diagnosis, and surveillance in HNC patients, with potential improvements in HNC patient outcomes. In this review, we examine current methodologies for detecting ctDNA and highlight current research illustrating viral and non-viral ctDNA biomarker utilities in HNC screening, diagnosis, treatment response, and prognosis. We also summarize current challenges and future directions for ctDNA testing in HNC patients.

Altered mRNA Expression of Fucosyltransferases and Fucosidase Predicts Prognosis in Human Oral Carcinoma

Aberrant protein glycosylation is known to be associated with the development of various cancers. Although fucosylation is essential for normal biological functions, alterations in fucosylation are strongly implicated in cancer and increasing metastatic potential. Altered fucosyltarnsferases (FUTs) and fucosidases are found to be involved in many types of malignancies. In this study, we examined the mRNA expressions of fucosidase (FUCA1) and FUTs (FUTs (FUT3, FUT4, FUT5, FUT6, FUT8) in human oral cancer tissues. All FUTs and FUCA1 were significantly (P ≤0.05) down-regulated in malignant tissues in comparison with their adjacent normal tissues. The relationship between the clinicopathological parameters and the expression of FUTs and FUCA1 revealed that higher mRNA levels of FUT4, FUT5, and FUT8 and lower levels of FUT3 were associated with progression of disease and lymph node metastasis in oral carcinoma indicating their role in oral cancer progression. Collectively, results suggest that elevated mRNA levels of FUT4, FUT5 and FUT8 may be used as worst prognostic indicators for oral carcinoma.

Cystatin-B Negatively Regulates the Malignant Characteristics of Oral Squamous Cell Carcinoma Possibly Via the Epithelium Proliferation/Differentiation Program

Disturbance in the proteolytic process is one of the malignant signs of tumors. Proteolysis is highly orchestrated by cysteine cathepsin and its inhibitors. Cystatin-B (CSTB) is a general cysteine cathepsin inhibitor that prevents cysteine cathepsin from leaking from lysosomes and causing inappropriate proteolysis. Our study found that CSTB was downregulated in both oral squamous cell carcinoma (OSCC) tissues and cells compared with normal controls. Immunohistochemical analysis showed that CSTB was mainly distributed in the epithelial structure of OSCC tissues, and its expression intensity was related to the grade classification. A correlation analysis between CSTB and clinical prognosis was performed using gene expression data and clinical information acquired from The Cancer Genome Atlas (TCGA) database. Patients with lower expression levels of CSTB had shorter disease-free survival times and poorer clinicopathological features (e.g., lymph node metastases, perineural invasion, low degree of differentiation, and advanced tumor stage). OSCC cell models overexpressing CSTB were constructed to assess the effects of CSTB on malignant biological behaviors and upregulation of CSTB inhibited cell proliferation, migration, and invasion in vitro. Weighted gene correlation network analysis (WGCNA) and gene set enrichment analysis (GSEA) were performed based on the TCGA data to explore potential mechanisms, and CSTB appeared to correlate with squamous epithelial proliferation-differentiation processes, such as epidermal cell differentiation and keratinization. Moreover, in WGCNA, the gene module most associated with CSTB expression (i.e., the brown module) was also the one most associated with grade classification. Upregulation of CSTB promoted the expression levels of markers (LOR, IVL, KRT5/14, and KRT1/10), reflecting a tendency for differentiation and keratinization in vitro. Gene expression profile data of the overexpressed CSTB cell line were obtained by RNA sequencing (RNA-seq) technology. By comparing the GSEA enrichment results of RNA-seq data (from the OSCC models overexpressing CSTB) and existing public database data, three gene sets (i.e., apical junction, G2/M checkpoint, etc.) and six pathways (e.g., NOTCH signaling pathway, glycosaminoglycan degradation, mismatch repair, etc.) were enriched in the data from both sources. Overall, our study shows that CSTB is downregulated in OSCC and might regulate the malignant characteristics of OSCC via the epithelial proliferation/differentiation program.

Identification of cytokeratin24 as a tumor suppressor for the management of head and neck cancer

To improve management of head and neck squamous cell carcinoma patients, we need to increase our understanding of carcinogenesis, to identify biomarkers, and drug targets. This study aimed to identify novel biomarkers by providing transcriptomics profiles of matched primary tumors, lymph node metastasis, and non-malignant tissue of 20 HNSCC patients as well as by bioinformatic analyses of a TCGA HNSCC cohort, comprising 554 patients. We provide cancer cell signaling networks differentially expressed in tumors versus metastases, such as mesenchymal-epithelial transition, and structural integrity networks. As a proof of principle study, we exploited the data sets and performed functional analyses of a novel cytokeratin, cytokeratin24 (cKRT24), which had not been described as biomarker for tumors before. Survival analysis revealed that low cKRT24 expression correlated with poor overall survival in HNSCC. Experimentally, downregulation of cKRT24 in primary tumors, metastases, and HNSCC cell lines was verified on mRNA and protein level. Cloning and ectopic overexpression of cKRT24 not only affected viability and growth of HNSSC cell lines, but also inhibited tumor growth in murine xenograft studies. We conclude that cKRT24 functions as a tumor suppressor in HNSCC, and may serve as an additional prognostic biomarker and novel target to support current HNSCC treatments.

Role of FAT1 in health and disease

FAT atypical cadherin 1 (FAT1), which encodes a protocadherin, is one of the most frequently mutated genes in human cancer. Over the past 20 years, the role of FAT1 in tissue growth and in the development of diseases has been extensively studied. There is definitive evidence that FAT1 serves a substantial role in the maintenance of organs and development, and its expression appears to be tissue-specific. FAT1 activates a variety of signaling pathways through protein-protein interactions, including the Wnt/β-catenin, Hippo and MAPK/ERK signaling pathways, which affect cell proliferation, migration and invasion. Abnormal FAT1 expression may lead to the development of tumors and may affect prognosis. Therefore, FAT1 may have potential in tumor therapy. The structural and functional changes mediated by FAT1, its tissue distribution and changes in FAT1 expression in human diseases are described in the present review, which provides further insight for understanding the role of FAT1 in development and disease.

High expression of regulator of G-protein signalling 1 is associated with the poor differentiation and prognosis of gastric cancer

Emerging evidence has highlighted that immune and stromal cells form the majority of the tumour microenvironment (TME), which plays important roles in tumour progression. The present study aimed to screen vital prognostic genes associated with the TME in gastric cancer (GC). The ESTIMATE algorithm was applied to calculate TME-related scores, and the relationship between clinicopathological variables and these scores was analysed. Heatmaps and Venn plots were then used to visualize and screen differentially expressed genes. Furthermore, functional enrichment analysis was performed, and a protein-protein interaction network was constructed. Kaplan-Meier curves were generated to evaluate survival differences for each hub gene. Reverse transcription quantitative PCR was employed to evaluate the expression of the three hub genes in the validation cohort. The association between gene expression, clinicopathological variables and survival was also evaluated. Higher stromal scores were associated with worse outcomes in patients with GC. In addition, higher scores were significantly associated with a higher tumour grade, American Joint Committee on Cancer stage and T stage with regard to immune scores, stromal scores and ESTIMATE scores, respectively. In total, 644 upregulated intersecting genes and 126 downregulated genes were identified. Moreover, 71 TME-associated hub genes were identified. Batch survival analysis revealed that higher expression of CXCR4, PTGFR and RGS1 was significantly associated with worse outcome. Subsequently, the relationship between high expression of RGS1 and poor prognosis was verified, and high expression of RGS1 was associated with poor differentiation. In conclusion, it was found that compared with immune cells, stromal cells may play a more important role in the prognosis of patients with GC. In addition, the influence of RGS1 expression on survival in GC patients was identified and verified, and high expression of RGS1 was found to be associated with a low differentiation degree of GC.

Mining TCGA database for prognostic genes in head and neck squamous cell carcinoma microenvironment

Background/purpose

Head and neck squamous cell carcinoma (HNSCC) is one of the most common malignant tumors. The aim of this study was to elucidate the effect of tumor microenvironment-related genes on the prognosis of HNSCC and to obtain tumor microenvironment-related genes that can predict poor prognosis in HNSCC patients.

Materials and methods

The ESTIMATE algorithm was applied to the HNSCC transcriptomic data downloaded from the TCGA (The cancer genome atlas), and then the samples were divided into two groups: high and low immune scoring groups, and high and low basal scoring groups to screen for differentially expressed genes (DEGs) associated with poor patient outcomes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was performed to explore the potential functions of DEGs, and then to explore the potential prognostic value of individual DEGs. The results of survival analysis between DEGs and overall survival (OS) to explore tumor microenvironment-related genes relevant to the prognosis of HNSCC patients.

Results

Fifty-nine tumor microenvironment-related genes were screened for association of OS with HNSCC (P < 0.05). The GO and KEGG enrichment analysis showed that the selected DEGs may mediate immune response, extracellular matrix, and immunoglobulin binding via neutrophil activation in HNSCC. Six of these DEGs, GIMAP6, SELL, TIFAB, KCNA3, P2RY8 and CCR4 were most significantly associated with OS (P < 0.001).

Conclusion

We identified six tumor microenvironment-related genes that were significantly associated with poor prognosis in HNSCC. These genes may inspire researchers to discover new targets and approaches for HNSCC treatment.

Essential gene expression pattern of head and neck squamous cell carcinoma revealed by tumor-specific expression rule based on single-cell RNA sequencing

Head and neck squamous cell carcinoma (HNSCC) has been widely reported and considered as one of the most threatening diseases to human health. Derived from complicated tissue subtypes, HNSCC has diverse symptoms and pathogenesis. They make the identification of the core carcinogenic factors of such diseases at the multi-cell level difficult. With the development of single-cell sequencing technologies, the effects of non-malignant cells on traditional bulk sequencing data can be eliminated directly. On the basis of fresh single-cell RNA-seq data, we set up a computational filtering strategy for tumor cell identification in an expression rule manner. This strategy can reveal the accurate expression distinction between tumor cells and adjacent tumor microenvironment, which are all supported by literature reports. Validated by several independent datasets, these rule genes can further group HNSCC patients with significant difference on survival risks. Thus, the establishment of our computational approach may not only provide an efficient tool to identify malignant cells in the tumor ecosystem but also deepen our understanding of tumor heterogeneity and tumorigenesis.

MicroRNA-222-3p participates in the development of oral squamous cell carcinoma by targeting CDKN1B

OBJECTIVE

The aim of this study was to explore the potential role and regulatory mechanism of microRNA (miR)-222-3p in oral squamous cell carcinoma (OSCC).

METHODS

The expression level and prognostic significance of miR-222-3p was detected in OSCC tissues. CCK-8, transwell, and flow cytometry assays were used to explore the effect of miR-222-3p on cell proliferation, migration, invasion, and apoptosis. The influence of miR-222-3p on cyclin-dependent kinase inhibitor 1B (CDKN1B) expression was evaluated by luciferase assays, real-time polymerase chain reaction, and Western blot.

RESULTS

We found that miR-222-3p was overexpressed in OSCC tissues, comparing with normal tissues. Kaplan-Meier curves showed that OSCC patients with high expression of miR-222-3p (P = .003) showed worse overall survival than those patients with low expression of miR-222-3p. Multivariate analysis showed that miR-222-3p (P = .037) expression was an independent prognostic factor of OSCC patients. miR-222-3p promoted cell proliferation, migration and invasion and induced the apoptosis of SCC-15 and Tca-83 cells. Furthermore, luciferase reporter assays indicated that CDKN1B is targeted by miR-222-3p in OSCC cells. Overexpression of CDKN1B inhibited OSCC cell proliferation, migration, and invasion and promoted cell apoptosis rate.

CONCLUSIONS

miR-222-3p affects OSCC cell proliferation, migration, invasion, and apoptosis through targeting CDKN1B, and may be a potential prognostic biomarker for OSCC patients.

Differential roles of protease isoforms in the tumor microenvironment

Alternative splicing of precursor mRNA is a key mediator of gene expression regulation leading to greater diversity of the proteome in complex organisms. Systematic sequencing of the human genome and transcriptome has led to our understanding of how alternative splicing of critical genes leads to multiple pathological conditions such as cancer. For many years, proteases were known only for their roles as proteolytic enzymes, acting to regulate/process proteins associated with diverse cellular functions. However, the differential expression and altered function of various protease isoforms, such as (i) anti-apoptotic activities, (ii) mediating intercellular adhesion, and (iii) modifying the extracellular matrix, are evidence of their specific contribution towards shaping the tumor microenvironment. Revealing the alternative splicing of protease genes and characterization of their protein products/isoforms with distinct and opposing functions creates a platform to understand how protease isoforms contribute to specific cancer hallmarks. Here, in this review, we address cancer-specific isoforms produced by the alternative splicing of proteases and their distinctive roles in the tumor microenvironment.

SMAD4 Somatic Mutations in Head and Neck Carcinoma Are Associated With Tumor Progression

As the incidence and the mortality rate of head and neck squamous cell carcinoma (HNSCC) is increasing worldwide, gaining knowledge about the genomic changes which happen in the carcinogenesis of HNSCC is essential for the diagnosis and therapy of the disease. SMAD4 (DPC4) is a tumor suppressor gene. It is located at chromosome 18q21.1 and a member of the SMAD family. Which mediates the TGF-β signaling pathway, thereby controlling the growth of epithelial cells. In the study presented here, we analyzed tumor samples by multiplex PCR-based next-generation sequencing (NGS) and found deleterious mutations of SMAD4 in 4.1% of the tumors. Knock-down experiments of endogenous and exogenous SMAD4 expression demonstrated that SMAD4 is involved in the migration and invasion of HNSCC cells. Functional analysis of a missense mutation in the MH1 domain of SMAD4 may be responsible for the loss of function in suppressing tumor progression. Missense SMAD4 mutations, therefore, could be useful prognostic determinants for patients affected by HNSCCs. This report is the first study where NGS analysis based on multiplex-PCR is used to demonstrate the imminent occurrence of missense SMAD4 mutations in HNSCC cells. The gene analysis that we performed may support the identification of SMAD4 mutations as a diagnostic marker or even as a potential therapeutic target in head and neck cancer. Moreover, the analytic strategy proposed for the detection of mutations in the SMAD4 gene may be validated as a platform to assist mutation screening.

FAT1 somatic mutations in head and neck carcinoma are associated with tumor progression and survival

In recent years, the incidence and mortality rates of head and neck squamous cell carcinoma (HNSCC) have increased worldwide. Therefore, understanding genomic alterations in HNSCC carcinogenesis is crucial for appropriate diagnosis and therapy. Protocadherin FAT1, which encodes 4588 amino acid residues, regulates complex mechanisms to promote oncogenesis or suppression of malignancies. Multiplex PCR-based next-generation sequencing (NGS) revealed FAT1 somatic mutations. The clinicopathologic implications of FAT1 in HNSCC were investigated using expression assays, and the functional role of FAT1 in HNSCC pathogenesis was determined using ectopic expression and knockdown experiments. Approximately 29% patients with HNSCC harbored damaging FAT1 mutations. InVEx algorithm identified FAT1 as a significant functional mutation burden. Each type of mutation (missense, nonsense and frameshift) accounted for nearly one-third of deleterious mutations. FAT1 mutations correlated with lower FAT1 expression in tumors. The knockdown of the endogenous expression of FAT1 and exogenous expression of crucial FAT1 domains unequivocally indicated that FAT1 suppressed the migration and invasion capability of HNSCC cells. Functional analysis suggested that nonsense mutations in FAT1 result in the loss of the suppression of tumor progression. FAT1 mutations and downregulation defined nodal involvement, lymphovascular permeation and tumor recurrence. In addition, FAT1 mutations and downregulation are independent predictors of poor disease-free survival in patients with HNSCC. This study is the first to perform multiplex PCR-based NGS to indicate marked non-synonymous FAT1 mutations in HNSCC, which are prognostic indicators. The gene analysis strategy proposed for detecting FAT1 mutations may be a valid method for mutation screening.

miR-125b suppresses oral oncogenicity by targeting the anti-oxidative gene PRXL2A

Oral squamous cell carcinoma (OSCC) is a globally prevalent malignancy. The molecular mechanisms of this cancer are not well understood and acquire elucidation. Peroxiredoxin like 2A (PRXL2A) has been reported to be an antioxidant protein that protects cells from oxidative stress. Our previous study identified an association between PRXL2A upregulation in OSCC and a worse patient prognosis. MicroRNAs (miRNAs) are small non-coding RNAs that are involved in the modulation of biological/pathological properties. The miR-125 family of genes drive pluripotent regulation across a wide variety of cancers. In this study, we identify the oncogenic eligibility of PRXL2A and clarify miR-125b as its upstream regulator. Downregulation of miR-125b can be observed in OSCC tumors. Lower miR-125b expression in tumors results in a worse patient prognosis at the relatively early stage. Reporter assays are able to validate that PRXL2A is a direct target of miR-125b. Exogenous miR-125b expression in OSCC cells results in increased oxidative stress, increased drug sensitivity, and suppressor activity that is paralleled by the knockout of PRXL2A gene. The suppressor activity of miR-125b is able to be rescued by PRXL2A, which suggests the existence of a miR-125b-PRXL2A regulatory axis that is part of OSCC pathogenesis. Nuclear factor-erythroid 2-related factor 2 (NRF2) was found to be a downstream effector of the miR-125b-PRXL2A cascade. As a whole, this study has pinpointed novel clues demonstrating that downregulation of miR-125b suppressor underlies upregulation of PRXL2A in OSCC, and this then protects the affected tumor cells from oxidative stress.

A functional gene expression analysis in epithelial sinonasal cancer: Biology and clinical relevance behind three histological subtypes

Epithelial sinonasal cancers (SNCs) are rare diseases with overlapping morphological features and a dismal prognosis. We aimed to investigate the expression differences among the histological subtypes for discerning their molecular characteristics. We selected 47 SNCs: (i) 21 nonkeratinizing squamous cell carcinomas (NKSCCs), (ii) 13 sinonasal neuroendocrine cancers (SNECs), and (iii) 13 sinonasal undifferentiated cancers (SNUCs). Gene expression profiling was performed by DASL (cDNA-mediated annealing, selection, extension, and ligation) microarray analysis with internal validation by quantitative RT-PCR (RT-qPCR). Relevant molecular patterns were uncovered by sparse partial-least squares discriminant analysis (sPLS-DA), microenvironment cell type (xCell), CIBERSORT, and gene set enrichment (GSEA) analyses. The first two sPLS-DA components stratified samples by histological subtypes. xCell highlighted increased expression of immune components (CD8⁺ effector memory cells, in SNUC) and "other cells": keratinocytes and neurons in NKSCC and SNEC, respectively. Pathway enrichment was observed in NKSCC (six gene sets, proliferation related), SNEC (one gene set, pancreatic β-cells), and SNUC (twenty gene sets, some of them immune-system related). Major neuroendocrine involvement was observed in all the SNEC samples. Our high-throughput analysis revealed a good diagnostic ability to differentiate NKSCC, SNEC, and SNUC, but indicated that the neuroendocrine pathway, typical and pathognomonic of SNEC is also present at lower expression levels in the other two histological subtypes. The different and specific profiles may be exploited for elucidating their biology and could help to identify prognostic and therapeutic opportunities.

Effect of serpinE1 overexpression on the primary tumor and lymph node, and lung metastases in head and neck squamous cell carcinoma

BACKGROUND

Serpin Family E Member 1 (SerpinE1) overexpression associates with poor clinical outcome in head and neck squamous cell carcinoma (HNSCC) patients. This study analyzed the role of serpinE1 in HNSCC dissemination.

METHODS

We studied the phenotypic characteristics and dissemination of HNSCC cells overexpressing serpinE1 using an orthotopic model and the association between serpinE1 overexpression and clinicopathological variables in patients included in The Cancer Genome Atlas database.

RESULTS

SerpinE1 overexpression increased proliferation, tumor budding, and the stromal component, while inhibiting apoptosis in primary tumors. It also enhanced the affectation and metastatic growth in lymph nodes, and the dispersion and growth of metastatic foci in the lung. High serpinE1 expression was associated with larger tumor size, undifferentiated tumors, lymph node metastasis, extracapsular spread, and the presence of perineural and angiolymphatic invasion.

CONCLUSION

SerpinE1 overexpression promotes tumor aggressiveness and metastatic dissemination to lymph nodes and lung consistently with its association with poor outcome in HNSCC patients.

Combined human papillomavirus typing and TP53 mutation analysis in distinguishing second primary tumors from lung metastases in patients with head and neck squamous cell carcinoma

BACKGROUND

In head and neck squamous cell carcinoma (HNSCC), the occurrence of concurrent lung malignancies poses a significant diagnostic challenge because metastatic HNSCC is difficult to discern from second primary lung squamous cell carcinoma (SCC). However, this differentiation is crucial because the recommended treatments for metastatic HNSCC and second primary lung SCC differ profoundly.

METHODS

We analyzed the origin of lung tumors in 32 patients with HNSCC using human papillomavirus (HPV) typing and targeted next generation sequencing of all coding exons of tumor protein 53 (TP53).

RESULTS

Lung tumors were clearly identified as HNSCC metastases or second primary tumors in 29 patients, thus revealing that 16 patients had received incorrect diagnoses based on clinical and morphological data alone.

CONCLUSION

The HPV typing and mutation analysis of all TP53 coding exons is a valuable diagnostic tool in patients with HNSCC and concurrent lung SCC, which can help to ensure that patients receive the most suitable treatment.

uPA/uPAR and SERPINE1 in head and neck cancer: role in tumor resistance, metastasis, prognosis and therapy

There is strong evidence supporting the role of the plasminogen activator system in head and neck squamous cell carcinoma (HNSCC), particularly of its uPA (urokinase plasminogen activator) / uPAR (urokinase plasminogen activator receptor) and SERPINE1 components. Overexpression of uPA/uPAR and SERPINE1 enhances tumor cell migration and invasion and plays a key role in metastasis development, conferring poor prognosis. The apparent paradox of uPA/uPAR and its inhibitor SERPINE1 producing similar effects is solved by the identification of SERPINE1 activated signaling pathways independent of uPA inhibition. Both uPA/uPAR and SERPINE1 are directly linked to the induction of epithelial-to-mesenchymal transition, the acquisition of stem cell properties and resistance to antitumor agents. The aim of this review is to provide insight on the deregulation of these proteins in all these processes.

We also summarize their potential value as prognostic biomarkers or potential drug targets in HNSCC patients. Concomitant overexpression of uPA/uPAR and SERPINE1 is associated with a higher risk of metastasis and could be used to identify patients that would benefit from an adjuvant treatment. In the future, the specific inhibitors of uPA/uPAR and SERPINE1, which are still under development, could be used to design new therapeutic strategies in HNSCCs.

MicroRNA-27b inhibits cell proliferation in oral squamous cell carcinoma by targeting FZD7 and Wnt signaling pathway

This study intended to investigate the role of microRNA-27b (miR-27b) in proliferation of oral squamous cell carcinoma (OSCC) cells and to explore the potential molecular mechanism. Cell proliferation was detected by MTT assay. The expression levels of miR-27b, Frizzled7 (FZD7), cyclin D1 and c-myc were detected by quantitative real time polymerase chain reaction (qRT-PCR). The protein expression level of FZD7 was detected by western blot analysis. The relationship between miR-27b and FZD7, and the activity of Wnt signaling pathway were determined using luciferase reporter assay. The miR-27b expression in OSCC cell lines was significantly decreased compared with control. Overexpression of miR-27b remarkably inhibited OSCC cell proliferation. Additionally, miR-27b could target and inhibit FZD7 expression and decrease the activity of Wnt signaling pathway.miR-27b could inhibit OSCC cell proliferation through inhibiting FZD7 and FZD7-mediated Wnt signaling pathway.

The IGF axis in HPV associated cancers

Human papillomaviruses (HPV) infect and replicate in stratified epithelium at cutaneous and mucosal surfaces. The proliferation and maintenance of keratinocytes, the cells which make up this epithelium, are controlled by a number of growth factor receptors such as the keratinocyte growth factor receptor (KGFR, also called fibroblast growth factor receptor 2b (FGFR2b)), the epithelial growth factor receptor (EGFR) and the insulin-like growth factor receptors 1 and 2 (IGF1R and IGF2R). In this review, we will delineate the mutation, gene transcription, translation and processing of the IGF axis within HPV associated cancers. The IGFs are key for developmental and postnatal growth of almost all tissues; we explore whether this crucial axis has been hijacked by HPV.

Constitutive expression of microRNA-150 in mammary epithelium suppresses secretory activation and impairs de novo lipogenesis

Profiling of RNA from mouse mammary epithelial cells (MECs) isolated on pregnancy day (P)14 and lactation day (L)2 revealed that the majority of differentially expressed microRNA declined precipitously between late pregnancy and lactation. The decline in miR-150, which exhibited the greatest fold-decrease, was verified quantitatively and qualitatively. To test the hypothesis that the decline in miR-150 is crucial for lactation, MEC-specific constitutive miR-150 was achieved by crossing ROSA26-lox-STOP-lox-miR-150 mice with WAP-driven Cre recombinase mice. Both biological and foster pups nursed by bitransgenic dams exhibited a dramatic decrease in survival compared with offspring nursed by littermate control dams. Protein products of predicted miR-150 targets Fasn, Olah, Acaca, and Stat5B were significantly suppressed in MECs of bitransgenic mice with constitutive miR-150 expression as compared with control mice at L2. Lipid profiling revealed a significant reduction in fatty acids synthesized by the de novo pathway in L2 MECs of bitransgenic versus control mice. Collectively, these data support the hypothesis that a synchronized decrease in miRNAs, such as miR-150, at late pregnancy serves to allow translation of targets crucial for lactation.

Enhanced cell migration and apoptosis resistance may underlie the association between high SERPINE1 expression and poor outcome in head and neck carcinoma patients

High SERPINE1 expression is a common event in head and neck squamous cell carcinoma (HNSCC); however, whether it plays a role in determining clinical outcome remains still unknown. We studied SERPINE1 as a prognostic marker in two HNSCC patient cohorts. In a retrospective study (n = 80), high expression of SERPINE1 was associated with poor progression-free (p = 0.022) and cancer-specific (p = 0.040) survival. In a prospective study (n = 190), high SERPINE1 expression was associated with poor local recurrence-free (p = 0.022), progression-free (p = 0.002) and cancer-specific (p = 0.006) survival. SERPINE1 expression was identified as an independent risk factor for progression-free survival in patients treated with chemo-radiotherapy or radiotherapy (p = 0.043). In both patient cohorts, high SERPINE1 expression increased the risk of metastasis spread (p = 0.045; p = 0.029). The association between SERPINE1 expression and survival was confirmed using the HNSCC cohort included in The Cancer Genome Atlas project (n = 507). Once again, patients showing high expression had a poorer survival (p < 0.001). SERPINE1 over-expression in HNSCC cells reduced cell proliferation and enhanced migration. It also protected cells from cisplatin-induced apoptosis, which was accompanied by PI3K/AKT pathway activation. Downregulation of SERPINE1 expression had the opposite effect. We propose SERPINE1 expression as a prognostic marker that could be used to stratify HNSCC patients according to their risk of recurrence.

Tyrosine 397 phosphorylation is critical for FAK-promoted Rac1 activation and invasive properties in oral squamous cell carcinoma cells

Oral squamous cell carcinoma (OSCC) is a common cancer worldwide. Despite advances in diagnosis and therapy, treatment options for patients with metastatic OSCC are few, due in part to the limited understanding of the molecular events involved in the invasion and metastasis of OSCC. In this study, we investigated the expression of focal adhesion kinase (FAK) and its tyrosine 397 phosphorylation (pY397) in the tissue specimens of OSCC. The roles of pY397 in regulating the activities of Rac1 and cortactin and the invasive properties of OSCC cells were further determined. Results from immunohistochemical analyses in 9 benign, 19 premalignant, and 19 malignant oral tissues showed that the immunoreactivity of FAK was observed in 5 benign (56%), 19 premalignant (100%), and 18 malignant tissues (95%), whereas the immunoreactivity of pY397 was only found in 1 of 9 (11%) benign lesions but was observed in 9 premalignant (47%) and 12 malignant (63%) lesions. Compared with the low-invading SCC4 cells, the high-invading OECM-1 cells exhibited higher levels of FAK expression and pY397, correlating with higher levels of GTP-bound Rac1 and cortactin phosphorylation. Manipulation of FAK expression or Y397 phosphorylation in SCC4, FaDu, OECM-1, or HSC-3 cells regulated their Rac1 activities and invasive properties. Furthermore, treatment of NSC23766, a Rac1-specific inhibitor, in OECM-1 and HSC-3 cells led to reduced invasive properties. Nevertheless, knockdown of FAK expression or suppression of pY397 had no effect on the cortactin activity in OECM-1 cells. The data collectively suggest that pY397 plays critical roles in the FAK-promoted Rac1 activation and invasive properties in OSCC cells. Thus, the inhibition of FAK phosphorylation at Y397 or Rac1 activity can serve as a therapeutic strategy for treating patients with metastatic OSCC.

Involvement of Kallikrein-Related Peptidases in Normal and Pathologic Processes

Human kallikrein-related peptidases (KLKs) are a subgroup of serine proteases that participate in proteolytic pathways and control protein levels in normal physiology as well as in several pathological conditions. Their complex network of stimulatory and inhibitory interactions may induce inflammatory and immune responses and contribute to the neoplastic phenotype through the regulation of several cellular processes, such as proliferation, survival, migration, and invasion. This family of proteases, which includes one of the most useful cancer biomarkers, kallikrein-related peptidase 3 or PSA, also has a protective effect against cancer promoting apoptosis or counteracting angiogenesis and cell proliferation. Therefore, they represent attractive therapeutic targets and may have important applications in clinical oncology. Despite being intensively studied, many gaps in our knowledge on several molecular aspects of KLK functions still exist. This review aims to summarize recent data on their involvement in different processes related to health and disease, in particular those directly or indirectly linked to the neoplastic process.

Prognostic significance of multiple kallikreins in high-grade astrocytoma

BACKGROUND

Kallikreins have clinical value as prognostic markers in a subset of malignancies examined to date, including kallikrein 3 (prostate specific antigen) in prostate cancer. We previously demonstrated that kallikrein 6 is expressed at higher levels in grade IV compared to grade III astrocytoma and is associated with reduced survival of GBM patients.

METHODS

In this study we determined KLK1, KLK6, KLK7, KLK8, KLK9 and KLK10 protein expression in two independent tissue microarrays containing 60 grade IV and 8 grade III astrocytoma samples. Scores for staining intensity, percent of tumor stained and immunoreactivity scores (IR, product of intensity and percent) were determined and analyzed for correlation with patient survival.

RESULTS

Grade IV glioma was associated with higher levels of kallikrein-immunostaining compared to grade III specimens. Univariable Cox proportional hazards regression analysis demonstrated that elevated KLK6- or KLK7-IR was associated with poor patient prognosis. In addition, an increased percent of tumor immunoreactive for KLK6 or KLK9 was associated with decreased survival in grade IV patients. Kaplan-Meier survival analysis indicated that patients with KLK6-IR < 10, KLK6 percent tumor core stained < 3, or KLK7-IR < 9 had a significantly improved survival. Multivariable analysis indicated that the significance of these parameters was maintained even after adjusting for gender and performance score.

CONCLUSIONS

These data suggest that elevations in glioblastoma KLK6, KLK7 and KLK9 protein have utility as prognostic markers of patient survival.

Upregulation of miR-372 and -373 associates with lymph node metastasis and poor prognosis of oral carcinomas

OBJECTIVES/HYPOTHESIS

Oral squamous cell carcinoma (OSCC) is prevalent worldwide, and survival in OSCC has not improved significantly in the last few decades. MicroRNAs (miRNAs) have an important regulatory role in human cancer, including oral carcinogenesis. MiR-372 and miR-373 perform oncogenic and tumor-suppressive functions of between different human malignancies. This study investigated the miR-372 and miR-373 expression and their clinical implication in OSCC.

METHODS

Fifty patients with primary OSCC were included in the study. Primary cancer cells and matched normal oral epithelium were purified by laser capture microdissection. RNA were extracted from these samples. The expression levels of miR-372 and miR-373 in the tissue of OSCC patients were measured by quantitative reverse transcription polymerase chain reaction. The large tumor suppressor kinase 2 (LATS2) protein expression level was measured by Western blotting.

RESULTS

Both miR-372 and miR-373 was up-regulated in OSCC tissue relative to control mucosa. Among different clinical variables, over-expression of miR-372 and miR-373 were associated with nodal metastasis, lymphovascular invasion, and poor survival. Multivariate analysis showed that both high miR-372 and miR-373 expression were independent predictors for poor survival in OSCC. MiR-372 regulated LATS2 expression in OSCC cell lines. LATS2 expression levels are inversely correlated miR-372 in OSCC tissues.

CONCLUSION

Over-expression of miR-372 and miR-373 indicate worse survival in OSCC.

LEVEL OF EVIDENCE

N/A.

Recent insights into the actions of IGFBP-6

IGFBP-6 is an O-linked glycoprotein that preferentially binds IGF-II over IGF-I. It is a relatively selective inhibitor of IGF-II actions including proliferation, survival and differentiation of a wide range of cells. IGFBP-6 has recently been shown to have a number of IGF-independent actions, including promotion of apoptosis in some cells and inhibition of angiogenesis. IGFBP-6 also induces migration of tumour cells including rhabdomyosarcomas by an IGF-independent mechanism. This chemotactic effect is mediated by MAP kinases. IGFBP-6 binds to prohibitin-2 on the cell surface and the latter is required for IGFBP-6-induced migration by a mechanism that is independent of MAP kinases. IGFBP-6 may enter the nucleus and modulate cell survival and differentiation. IGFBP-6 expression is decreased in a number of cancer cells and it has been postulated to act as a tumour suppressor. IGFBP-6 expression is increased in a smaller number of cancers, which may reflect a compensatory mechanism to control IGF-II actions or IGF-independent actions. The relative balance of IGF-dependent and IGF-independent actions of IGFBP-6 in vivo together with the related question regarding the roles of IGFBP-6 binding to IGF and non-IGF ligands are keys to understanding the physiological role of this protein.

E-selectin expression and BRAF status in papillary thyroid carcinomas: Correlation with clinicopathologic features

BACKGROUND

Cell adhesion molecules, represented by the immunoglobulin family and selectins, play an important role in the progression of cancer. A correlation between selectins and tumor aggressiveness has been demonstrated in several reports.

METHODS

Eighty-eight patients (mean age, 41.0 ± 14 years) with papillary thyroid carcinoma (conventional variant and sized approximately 20 mm) were divided in 2 groups: 41 with encapsulated tumors and 47 with tumors with extrathyroidal extension. E-selectin expression was evaluated by immunohistochemical staining and semiquantitative real-time reverse-transcription polymerase chain reaction and normalized by calculating the z-score (positive: value above the population mean; negative: below the mean).

RESULTS

Lymph node metastasis (LNM) was found in 2 of 41 encapsulated tumors (4.8%) and in 19 of 47 tumors (40.4%) with extrathyroidal extension. BRAF mutation was present in 21 encapsulated tumors (51.2%) and in 31 tumors with extrathyroidal extension (65.9%). The mean E-selectin z-score was -0.32 for encapsulated tumors and 0.28 for tumors with extrathyroidal extension. E-selectin expression correlates with neoplastic infiltration (P = .04), the American Joint Commission on Cancer stage (P = .02), and BRAF mutation (P = .03).

CONCLUSION

E-selectin overexpression in association with BRAF mutation status could promote a more aggressive phenotype in papillary thyroid carcinoma.

SERPINE1 and SMA expression at the invasive front predict extracapsular spread and survival in oral squamous cell carcinoma

BACKGROUND

Extracapsular spread (ECS) in cervical lymph nodes is the single-most prognostic clinical variable in oral squamous cell carcinoma (OSCC), but diagnosis is possible only after histopathological examination. A promising biomarker in the primary tumour, alpha smooth muscle actin (SMA) has been shown to be highly prognostic, however, validated biomarkers to predict ECS prior to primary treatment are not yet available.

METHODS

In 102 OSCC cases, conventional imaging was compared with pTNM staging. SERPINE1, identified from expression microarray of primary tumours as a potential biomarker for ECS, was validated through mRNA expression, and by immunohistochemistry (IHC) on a tissue microarray from the same cohort. Similarly, expression of SMA was also compared with its association with ECS and survival. Expression was analysed separately in the tumour centre and advancing front; and prognostic capability determined using Kaplan-Meier survival analysis.

RESULTS

Immunohistochemistry indicated that both SERPINE1 and SMA expression at the tumour-advancing front were significantly associated with ECS (P<0.001). ECS was associated with expression of either or both proteins in all cases. SMA+/SERPINE1+ expression in combination was highly significantly associated with poor survival (P<0.001). MRI showed poor sensitivity for detection of nodal metastasis (56%) and ECS (7%). Both separately, and in combination, SERPINE1 and SMA were superior to MRI for the detection of ECS (sensitivity: SERPINE1: 95%; SMA: 82%; combination: 81%).

CONCLUSION

A combination of SMA and SERPINE1 IHC offer potential as prognostic biomarkers in OSCC. Our findings suggest that biomarkers at the invasive front are likely to be necessary in prediction of ECS or in therapeutic stratification.

Microarray analysis of serum mRNA in patients with head and neck squamous cell carcinoma at whole-genome scale

With the increasing demand for noninvasive approaches in monitoring head and neck cancer, circulating nucleic acids have been shown to be a promising tool. We focused on the global transcriptome of serum samples of head and neck squamous cell carcinoma (HNSCC) patients in comparison with healthy individuals. We compared gene expression patterns of 36 samples. Twenty-four participants including 16 HNSCC patients (from 12 patients we obtained blood samples 1 year posttreatment) and 8 control subjects were recruited. The Illumina HumanWG-6 v3 Expression BeadChip was used to profile and identify the differences in serum mRNA transcriptomes. We found 159 genes to be significantly changed (Storey's P value <0.05) between normal and cancer serum specimens regardless of factors including p53 and B-cell lymphoma family members (Bcl-2, Bcl-XL). In contrast, there was no difference in gene expression between samples obtained before and after surgery in cancer patients. We suggest that microarray analysis of serum cRNA in patients with HNSCC should be suitable for refinement of early stage diagnosis of disease that can be important for development of new personalized strategies in diagnosis and treatment of tumours but is not suitable for monitoring further development of disease.

Fluctuation of Rac1 activity is associated with the phenotypic and transcriptional heterogeneity of glioma cells

Phenotypic heterogeneity of cancer cells is caused not only by genetic and epigenetic alterations but also by stochastic variation of intracellular signaling molecules. Using cells that stably express Förster resonance energy transfer (FRET) biosensors, we show here a correlation between a temporal fluctuation in the activity of Rac1 and the invasive properties of C6 glioma cells. By using long-term time-lapse imaging, we found that Rac1 activity in C6 glioma cells fluctuated over a timescale that was substantially longer than that of the replication cycle. Because the relative level of Rac1 activity in each cell was unaffected by a suspension-adhesion procedure, we were able to sort C6 glioma cells according to the levels of Rac1 activity, yielding Rac1(high) and Rac1(low) cells. The Rac1(high) cells invaded more efficiently than did Rac1(low) cells in a Matrigel invasion assay. We assessed the transcriptional profiles of Rac1(high) and Rac1(low) cells and performed gene ontology analysis. Among the 14 genes that were most associated with the term 'membrane' (membrane-related genes) in Rac1(high) cells, we identified four genes that were associated with glioma invasion and Rac1 activity by using siRNA knockdown experiments. Among the transcription factors upregulated in Rac1(high) cells, Egr2 was found to positively regulate expression of the four membrane-related invasion-associated genes. The identified signaling network might cause the fluctuations in Rac1 activity and the heterogeneity in the invasive capacity of glioma cells.

Genetic variations in regulator of G-protein signaling (RGS) confer risk of bladder cancer

BACKGROUND

Alterations in the regulator of G-protein signaling (RGS) pathway have been implicated in several cancers; therefore, the authors investigated the role of such alterations in overall bladder cancer risk, recurrence, progression, and survival.

METHODS

In this case-control series, 803 patients with bladder cancer were frequency-matched with a control cohort of 803 healthy individuals. Ninety-five single-nucleotide polymorphisms (SNPs) in 17 RGS genes were investigated for an association with overall bladder cancer risk, recurrence, and progression in patients who had nonmuscle-invasive bladder cancer (NMIBC) and for an association with death in patients who had muscle-invasive bladder cancer (MIBC). Cumulative effects and classification and regression tree analyses were performed for SNPs that were associated with overall bladder cancer risk. Kaplan-Meier plots were created to evaluate differences in the survival of patients with MIBC.

RESULTS

Reference SNP 10759 (rs10759) on the RGS4 gene demonstrated the greatest association with overall bladder cancer risk, conferring a 0.77-fold reduced risk with an increasing number of variant alleles (P < .001). A cumulative effects analysis that included all 5 significant SNPs demonstrated an increasing risk with the number of unfavorable genotypes (odds ratio, 4.13; 95% confidence interval, 2.14-7.98). In patients with NMIBC, 11 SNPs were identified that had an association with disease recurrence, and 13 SNPs were associated with disease progression. Of the 10 SNPs that were associated with death in patients with MIBC, rs2344673 in an additive model was the most significant and was associated with a decreased median survival of 13.3 months compared with 81.9 months in individuals without a variant allele.

CONCLUSIONS

Genetic variations in the RGS pathway were associated with the overall risk of bladder cancer, recurrence, and progression in patients with NMIBC and with the risk of death in patients with MIBC.

Identification of ovarian cancer metastatic miRNAs

Serous epithelial ovarian cancer (EOC) patients often succumb to aggressive metastatic disease, yet little is known about the behavior and genetics of ovarian cancer metastasis. Here, we aim to understand how omental metastases differ from primary tumors and how these differences may influence chemotherapy. We analyzed the miRNA expression profiles of primary EOC tumors and their respective omental metastases from 9 patients using miRNA Taqman qPCR arrays. We find 17 miRNAs with differential expression in omental lesions compared to primary tumors. miR-21, miR-150, and miR-146a have low expression in most primary tumors with significantly increased expression in omental lesions, with concomitant decreased expression of predicted mRNA targets based on mRNA expression. We find that miR-150 and miR-146a mediate spheroid size. Both miR-146a and miR-150 increase the number of residual surviving cells by 2-4 fold when challenged with lethal cisplatin concentrations. These observations suggest that at least two of the miRNAs, miR-146a and miR-150, up-regulated in omental lesions, stimulate survival and increase drug tolerance. Our observations suggest that cancer cells in omental tumors express key miRNAs differently than primary tumors, and that at least some of these microRNAs may be critical regulators of the emergence of drug resistant disease.

Genomic profiling of oral squamous cell carcinoma by array-based comparative genomic hybridization

We designed a study to investigate genetic relationships between primary tumors of oral squamous cell carcinoma (OSCC) and their lymph node metastases, and to identify genomic copy number aberrations (CNAs) related to lymph node metastasis. For this purpose, we collected a total of 42 tumor samples from 25 patients and analyzed their genomic profiles by array-based comparative genomic hybridization. We then compared the genetic profiles of metastatic primary tumors (MPTs) with their paired lymph node metastases (LNMs), and also those of LNMs with non-metastatic primary tumors (NMPTs). Firstly, we found that although there were some distinctive differences in the patterns of genomic profiles between MPTs and their paired LNMs, the paired samples shared similar genomic aberration patterns in each case. Unsupervised hierarchical clustering analysis grouped together 12 of the 15 MPT-LNM pairs. Furthermore, similarity scores between paired samples were significantly higher than those between non-paired samples. These results suggested that MPTs and their paired LNMs are composed predominantly of genetically clonal tumor cells, while minor populations with different CNAs may also exist in metastatic OSCCs. Secondly, to identify CNAs related to lymph node metastasis, we compared CNAs between grouped samples of MPTs and LNMs, but were unable to find any CNAs that were more common in LNMs. Finally, we hypothesized that subpopulations carrying metastasis-related CNAs might be present in both the MPT and LNM. Accordingly, we compared CNAs between NMPTs and LNMs, and found that gains of 7p, 8q and 17q were more common in the latter than in the former, suggesting that these CNAs may be involved in lymph node metastasis of OSCC. In conclusion, our data suggest that in OSCCs showing metastasis, the primary and metastatic tumors share similar genomic profiles, and that cells in the primary tumor may tend to metastasize after acquiring metastasis-associated CNAs.

Insulin-like growth factor-binding protein-6 and cancer

The IGF (insulin-like growth factor) system is essential for physiological growth and it is also implicated in a number of diseases including cancer. IGF activity is modulated by a family of high-affinity IGF-binding proteins, and IGFBP-6 is distinctive because of its marked binding preference for IGF-II over IGF-I. A principal role for IGFBP-6 is inhibition of IGF-II actions, but recent studies have indicated that IGFBP-6 also has IGF-independent effects, including inhibition of angiogenesis and promotion of cancer cell migration. The present review briefly summarizes the IGF system in physiology and disease before focusing on recent studies on the regulation and actions of IGFBP-6, and its potential roles in cancer cells. Given the widespread interest in IGF inhibition in cancer therapeutics, increasing our understanding of the mechanisms underlying the actions of the IGF ligands, receptors and binding proteins, including IGFBP-6, will enhance our ability to develop optimal treatments that can be targeted to the most appropriate patients.

Epigenetic and genetic alterations-based molecular classification of head and neck cancer

The long-term survival rates for patients diagnosed with advanced head and neck cancer (HNC) remain poor. Many perplexing factors, including etiology and comorbidity, lead to different molecular malfunctions of HNC cells and determine the prognosis of the disease. Traditional diagnostic methods are limited in that they fail to provide an effective classification diagnosis, such as a more precise prediction of prognosis and decisions for personalized treatment regimens. Recently, molecular biology techniques, especially epigenetic and genetic techniques, have been developed that have enabled us to gain a greater insight into the molecular pathways underlying the cancers. Translating the research into a format that will facilitate effective molecular classification, support personalized treatment and determine prognosis remains a challenge. In this review, the authors provide an overview of cancer epigenetic and genetic alterations, tissue banks, and several promising biomarkers or candidates that may ultimately prove to be beneficial in a clinical setting for patients with HNC.

Opportunities and challenges facing biomarker development for personalized head and neck cancer treatment

Head and neck oncologists have traditionally relied on clinical tumor features and patient characteristics to guide care of individual patients. As surgical, radiotherapeutic, and systemic treatments have evolved to become more anatomically precise and mechanistically specific, the opportunity for improved cure and functional patient recovery has never been more promising for this historically debilitating cancer. However, personalized treatment must be accompanied by sophisticated patient selection to triage the application of advanced therapies toward ideal patient candidates. In this monograph, we review current progress, investigative themes, and key challenges facing head and neck cancer biomarker development intended to make personalized head and neck cancer treatment a clinical reality.

Downregulation of Ches1 and other novel genes in oral cancer cells chronically exposed to areca nut extract

BACKGROUND

This study was undertaken to identify the genes in response to areca nut extract, a potential carcinogen of oral cancer.

METHODS

Two oral cancer sublines chronically treated with areca nut extract were established. Methods such as microarray and immunohistochemistry were used to screen and validate the genes' altered expressions in areca nut extract-sublines or in cancer tissues.

RESULTS

A total of 35 genes were differentially expressed in both sublines. Several functional pathways were significantly altered. Six genes were confirmed over 2-fold of changes, including Ches1. Functional analyses showed that overexpression of Ches1 suppressed cell growth and arrested cells in the G2/M phase. Consistently, this gene has reduced expression in 52% of oral cancer tissues, which was significantly correlated with the areca nut chewing habit of patients (p = .04).

CONCLUSION

We identified 35 candidates and validated 6 genes that may be associated with areca nut-induced oral cancer. Loss of Ches1 may be attributed to areca nut extract-induced oral carcinogenesis.

MicroRNA-200c attenuates tumour growth and metastasis of presumptive head and neck squamous cell carcinoma stem cells

MicroRNA-200c (miR200c) is emerging as an important regulator of tumourigenicity and cancer metastasis with a strong capacity for inducing epithelial-mesenchymal transitions. However, the role of miR200c in head and neck squamous cell carcinoma (HNSCC) and HNSCC-associated cancer stem cells (HNSCC-CSCs) is unknown. In this study, the expression of miR200c in the regional metastatic lymph node of HNSCC tissues was significantly decreased, but BMI1 expression was increased as compared to parental tumours. Importantly, site-directed mutagenesis with a luciferase reporter assay showed that miR200c targeted the 3' UTR of BMI1 in HNSCC cells. Isolated HNSCC-derived ALDH1(+) /CD44(+) cells displayed CSC-like tumour initiating and radio-resistant properties. The expression levels of miR200c were significantly down-regulated while BMI1 was increased in HNSCC-ALDH1(+) /CD44(+) compared to the other subsets of HNSCC cells. Furthermore, increased miR200c expression or knockdown of BMI1 could significantly inhibit the malignant CSC-like properties of ALDH1(+) /CD44(+) cells. miR200c over-expression further down-regulated the expressions of ZEB1, Snail and N-cadherin, but up-regulated E-cadherin expression in ALDH1(+) /CD44(+) cells. Finally, a xenotransplantion study confirmed that over-expression of miR200c or BMI1 knockdown effectively inhibited the lung metastatic ability and prolonged the survival rate of ALDH1(+) /CD44(+) -transplanted mice. In summary, miR200c negatively modulates the expression of BMI1 but also significantly inhibits the metastatic capability of epithelial-mesenchymal transitions in malignant HNSCC by reducing the expression of BMI1/ZEB1. Restoration of miR200c in HNSCC and CSCs may be a promising therapeutic approach.

Portrait of ependymoma recurrence in children: biomarkers of tumor progression identified by dual-color microarray-based gene expression analysis

Background

Children with ependymoma may experience a relapse in up to 50% of cases depending on the extent of resection. Key biological events associated with recurrence are unknown.

Methodology/Principal Findings

To discover the biology behind the recurrence of ependymomas, we performed CGHarray and a dual-color gene expression microarray analysis of 17 tumors at diagnosis co-hybridized with the corresponding 27 first or subsequent relapses from the same patient. As treatment and location had only limited influence on specific gene expression changes at relapse, we established a common signature for relapse. Eighty-seven genes showed an absolute fold change ≥2 in at least 50% of relapses and were defined as the gene expression signature of ependymoma recurrence. The most frequently upregulated genes are involved in the kinetochore (ASPM, KIF11) or in neural development (CD133, Wnt and Notch pathways). Metallothionein (MT) genes were downregulated in up to 80% of the recurrences. Quantitative PCR for ASPM, KIF11 and MT3 plus immunohistochemistry for ASPM and MT3 confirmed the microarray results. Immunohistochemistry on an independent series of 24 tumor pairs at diagnosis and at relapse confirmed the decrease of MT3 expression at recurrence in 17/24 tumor pairs (p = 0.002). Conversely, ASPM expression was more frequently positive at relapse (87.5% vs 37.5%, p = 0.03). Loss or deletion of the MT genes cluster was never observed at relapse. Promoter sequencing after bisulfite treatment of DNA from primary tumors and recurrences as well as treatment of short-term ependymoma cells cultures with a demethylating agent showed that methylation was not involved in MT3 downregulation. However, in vitro treatment with a histone deacetylase inhibitor or zinc restored MT3 expression.

Conclusions/Significance

The most frequent molecular events associated with ependymoma recurrence were over-expression of kinetochore proteins and down-regulation of metallothioneins. Metallothionein-3 expression is epigenetically controlled and can be restored in vitro by histone deacetylase inhibitors.

Integrative analysis of DNA copy number and gene expression in metastatic oral squamous cell carcinoma identifies genes associated with poor survival

Background

Lymphotropism in oral squamous cell carcinoma (OSCC) is one of the most important prognostic factors of 5-year survival. In an effort to identify genes that may be responsible for the initiation of OSCC lymphotropism, we examined DNA copy number gains and losses and corresponding gene expression changes from tumor cells in metastatic lymph nodes of patients with OSCC.

Results

We performed integrative analysis of DNA copy number alterations (CNA) and corresponding mRNA expression from OSCC cells isolated from metastatic lymph nodes of 20 patients using Affymetrix 250 K Nsp I SNP and U133 Plus 2.0 arrays, respectively. Overall, genome CNA accounted for expression changes in 31% of the transcripts studied. Genome region 11q13.2-11q13.3 shows the highest correlation between DNA CNA and expression. With a false discovery rate < 1%, 530 transcripts (461 genes) demonstrated a correlation between CNA and expression. Among these, we found two subsets that were significantly associated with OSCC (n = 122) when compared to controls, and with survival (n = 27), as tested using an independent dataset with genome-wide expression profiles for 148 primary OSCC and 45 normal oral mucosa. We fit Cox models to calculate a principal component analysis-derived risk-score for these two gene sets ('122-' or '27-transcript PC'). The models combining the 122- or 27-transcript PC with stage outperformed the model using stage alone in terms of the Area Under the Curve (AUC = 0.82 or 0.86 vs. 0.72, with p = 0.044 or 0.011, respectively).

Conclusions

Genes exhibiting CNA-correlated expression may have biological impact on carcinogenesis and cancer progression in OSCC. Determination of copy number-associated transcripts associated with clinical outcomes in tumor cells with an aggressive phenotype (i.e., cells metastasized to the lymph nodes) can help prioritize candidate transcripts from high-throughput data for further studies.

Cytogenetic characterization of head and neck squamous cell carcinoma cell lines as model systems for the functional analyses of tumor-associated genes

Head and neck squamous cell carcinoma (HNSCC) is a solid malignant neoplasm exhibiting aggressive phenotypes and high recurrence rates. To improve its clinical management, understanding the molecular basis of HNSCC development is of critical importance. For the investigation of tumor-associated genes, functional analyses in well-characterized tumor cell systems are required. To establish an experimental platform, a set of 20 HNSCC cell lines was screened for genetic imbalances by chromosomal comparative genomic hybridization (cCGH). Frequent DNA copy number gains were detected on 3q26.3-qter, 5p, 7p11-p13, 8q23-qter, 9p11-p13, 9q31-qter, 11q13 and 20q13.1, whereas copy number losses were found on 3p, 4p, 4q32.1-qter, 8p11-p12 and 18q22 in agreement with previous observations on genetic aberrations detected in primary HNSCC specimens. Subsequent mRNA expression analysis of 11q13 candidate genes CCND1 and CTTN revealed that HNSCC cell lines exhibiting a DNA copy number gain on 11q13 had a higher transcript level of CCND1 and CTTN compared with HNSCC cell lines without 11q13 copy number gain (P = 0.014 and P = 0.009, respectively). Furthermore, CCND1 and CTTN amplification as detected by fluorescence in situ hybridization correlated with protein expression as assessed by immunocytochemistry. In summary, the cytogenetic characterization illustrates that this set of HNSCC cell lines is representative for the HNSCC genome and provides tumor model systems for detailed analysis of genes with a possible role in the pathomechanism of head and neck tumors.

Decreased expression of miR-125b and miR-100 in oral cancer cells contributes to malignancy

Altered microRNA (miRNA) expression profiles have been observed in numerous malignancies, including oral squamous cell carcinoma (OSCC). However, their role in disease is not entirely clear. Several genetic aberrations are characteristic of OSCC, with amplification of chromosomal band 11q13 and loss of distal 11q being among the most prevalent. It is not known if the expression levels of miRNAs in these regions are altered or whether they play a role in disease. We hypothesize that the expression of miRNAs mapping to 11q are altered in OSCC because of loss or amplification of chromosomal material, and that this contributes to the development and progression of OSCC. We found that miR-125b and miR-100 are down-regulated in OSCC tumor and cell lines, and that transfecting cells with exogenous miR-125b and miR-100 significantly reduced cell proliferation and modified the expression of target and nontarget genes, including some that are overexpressed in radioresistant OSCC cells. In conclusion, the down-regulation of miR-125b and miR-100 in OSCC appears to play an important role in the development and/or progression of disease and may contribute to the loss of sensitivity to ionizing radiation.

Regulator of G-protein signaling (RGS) proteins in cancer biology

The regulator of G-protein signaling (RGS) family is a diverse group of multifunctional proteins that regulate cellular signaling events downstream of G-protein coupled receptors (GPCRs). In recent years, GPCRs have been linked to the initiation and progression of multiple cancers; thus, regulators of GPCR signaling are also likely to be important to the pathophysiology of cancer. This review highlights recent studies detailing changes in RGS transcript expression during oncogenesis, single nucleotide polymorphisms in RGS proteins linked to lung and bladder cancers, and specific roles for RGS proteins in multiple cancer types.

Transcriptome profiling and network pathway analysis of genes associated with invasive phenotype in oral cancer

The aim of this study was to clarify relevant alterations of gene expression associated with the invasive phenotype of oral cancer. To reduce heterogeneity and to obtain data on genes specifically involved in invasive mechanism, we established a highly invasive ORC subline through in vitro Matrigel invasion method. Affymetrix microarrays were used for transcriptome profiling between parental and the highly invasive subline. Seventy-nine genes were differentially expressed at least 2-fold, including 38 up-regulated and 41 down-regulated. After analyzing the microarray data by MetaCore algorithm, a total of 12 regulatory pathways were found to be associated with invasive phenotype (p<0.001). Two functional pathways were most significant: the cell adhesion through extracellular matrix remodeling (p=4.964e-06), and MHC-class-I mediated antigen presentation (p=9.843e-05). To shed more light on the biological functions of invasiveness, two genes highly over-expressed in the invasive subline, Cyr61 and CD44 were further validated. RNAi knockdown of these two genes led to significant suppression of cell growth (32% and 31%, respectively at day 3), cell migration (45% and 96%, respectively at 24 h), and cell invasion (83% and 87%, respectively at day 3). These results suggested important roles of these genes in regulating invasive phenotype, and demonstrated the confidence of this study design in the search of invasive associated genes. The identified pathways associated with invasion mechanism may be novel targets for manipulation of the cancer behavior with consequences on treatment outcome.

Detection and screening of oral cancer and pre-cancerous lesions

Oral cancer is a fatal disease, accounting for the fourth highest incidence of malignancy in males and the seventh in females in Taiwan. The relatively high prevalence of oral cancer in Taiwan is mainly because there is a high-risk group of 2.5 million people with the habit of smoking and betel nut chewing. Unfortunately, 50% of new cases in our medical center who present with TNM stage III or IV lesions have a shorter than 5-year survival after treatment. This highlights the need for: (1) early treatment of fresh oral cancer cases; (2) screening of the high-risk population to detect new lesions; (3) careful follow-up of cases after treatment; and (4) detection of occult early neck nodal adenopathy in surgical cases. It is generally accepted that prevention and screening of oral cancer are equally important to treatment due to its location. In this review article, we describe the nature of oral cancer and highlight the various conventional and novel methods of screening for this disease and ongoing important related research. Related literature is reviewed and future work that needs to be done is detailed.