Diana Messadi

Treatment with siRNA and antisense oligonucleotides targeted to HIF-1α induced apoptosis in human tongue squamous cell carcinomas

Overexpression of hypoxia inducible factor‐1α (HIF‐1α) in cancers has been correlated to a more aggressive tumor phenotype. We investigated the effect of HIF‐1α knockout on the in vitro survival and death of human tongue squamous cell carcinomas (SCC‐4 and SCC‐9). Under normoxic condition, a basal level of HIF‐1α protein was constitutively expressed in SCC‐9 cells, albeit an undetectable level of HIF‐1α messages. Exposure to hypoxia induced only a transient increase in mRNA transcript but a prolonged elevation of HIF‐1α protein and its immediate downstream target gene product, VEGF. Under normoxic or hypoxic conditions, treatment of SCC‐9 cells with AS‐HIF‐1α ODN suppressed both constitutive and hypoxia‐induced HIF‐1α expression at both mRNA and protein levels. Knockout of HIF‐1α gene expression via either AS‐HIF‐1α ODN or siRNA (siRNAHIF‐1α) treatment resulted in inhibition of cell proliferation and induced apoptosis in SCC‐4 and SCC‐9 cells. We also demonstrated that exposure of SCC‐9 cells to hypoxia led to a time‐dependent increase in the expression of bcl‐2 and IAP‐2, but not p53. The attenuated levels of bcl‐2 and IAP‐2, and the enhanced activity of caspase‐3 after treatment with AS‐HIF‐1α ODN may contribute partly to the effects of HIF‐1α blockade on SCC‐9 cell death. Collectively, our data suggest that a constitutive or hypoxia‐induced expression of HIF‐1α in SCC‐9 and SCC‐4 cells is sufficient to confer target genes expression essential for tumor proliferation and survival. As a result, interfering with HIF‐1α pathways by antisense or siRNA strategy may provide a therapeutic target for human tongue squamous cell carcinomas.

Prevalidation of Salivary Biomarkers for Oral Cancer Detection

Background: Oral cancer is the sixth most common cancer with a 5-year survival rate of approximately 60%. Presently, there are no scientifically credible early detection techniques beyond conventional clinical oral examination. The goal of this study is to validate whether the seven mRNAs and three proteins previously reported as biomarkers are capable of discriminating patients with oral squamous cell carcinomas (OSCC) from healthy subjects in independent cohorts and by a National Cancer Institute (NCI)-Early Detection Research Network (EDRN)-Biomarker Reference Laboratory (BRL). Methods: Three hundred and ninety-five subjects from five independent cohorts based on case controlled design were investigated by two independent laboratories, University of California, Los Angeles (Los Angeles, CA) discovery laboratory and NCI-EDRN-BRL. Results: Expression of all seven mRNA and three protein markers was increased in OSCC versus controls in all five cohorts. With respect to individual marker performance across the five cohorts, the increase in interleukin (IL)-8 and subcutaneous adipose tissue (SAT) was statistically significant and they remained top performers across different cohorts in terms of sensitivity and specificity. A previously identified multiple marker model showed an area under the receiver operating characteristic (ROC) curve for prediction of OSCC status ranging from 0.74 to 0.86 across the cohorts. Conclusions: The validation of these biomarkers showed their feasibility in the discrimination of OSCCs from healthy controls. Established assay technologies are robust enough to perform independently. Individual cutoff values for each of these markers and for the combined predictive model need to be further defined in large clinical studies. Impact: Salivary proteomic and transcriptomic biomarkers can discriminate oral cancer from control subjects. Cancer Epidemiol Biomarkers Prev; 21(4); 664–72. ©2012 AACR.

Diagnostic aids for detection of oral precancerous conditions

Oral cancer has a tendency to be detected at late stage which is detrimental to the patients because of its high mortality and morbidity rates. Early detection of oral cancer is therefore important to reduce the burden of this devastating disease. In this review article, the most common oral precancerous lesions are discussed and the importance of early diagnosis is emphasized. In addition, the most common non-invasive oral cancer devices that can aid the general practitioners in early diagnosis are also discussed.

In vivo diagnosis of oral dysplasia and malignancy using optical coherence tomography: Preliminary studies in 50 patients

In vivo, non‐invasive optical coherence tomography (OCT) permits high‐resolution imaging of tissue surfaces and subsurfaces, with the potential capability for detection and mapping of epithelial pathologies.

Increased Plasminogen Activator Inhibitor-1 in Keloid Fibroblasts May Account for their Elevated Collagen Accumulation in Fibrin Gel Cultures

Proteolytic degradation of the provisional fibrin matrix and subsequent substitution by fibroblast-produced collagen are essential features of injury repair. Immunohistochemical studies revealed that although dermal fibroblasts of normal scars and keloids expressed both urokinase type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1), keloid fibroblasts had a much higher PAI-1 expression. In long-term three-dimensional fibrin gel cultures (the in vitro fibroplasia model), normal fibroblasts expressed moderate and modulated activity levels of uPA and PAI-1. In contrast, keloid fibroblasts expressed a persistently high level of PAI-1 and a low level of uPA. The high PAI-1 activity of keloid fibroblasts correlated with their elevated collagen accumulation in fibrin gel cultures. Substituting collagen for fibrin in the gel matrix resulted in increased uPA activity and reduced collagen accumulation of keloid fibroblasts. Furthermore, decreasing PAI-1 activity of keloid fibroblasts in fibrin gel cultures with anti-PAI-1-neutralizing antibodies also resulted in a reduction in collagen accumulation by keloid fibroblasts. Cumulatively, these results suggest that PAI-1 overexpression is a consistent feature of keloid fibroblasts both in vitro and in vivo, and PAI-1 may play a causative role in elevated collagen accumulation of keloid fibroblasts.

Expression of apoptosis‐associated genes by human dermal scar fibroblasts

The purpose of this study was to determine if aberrant apoptosis plays a role in pathologic wound healing as manifested by hypertrophic scarring and keloid formation. Apoptosis has recently been found to participate in the transition between granulation tissue and the development of definitive scar. The question that remains to be answered is what stimuli initiate apoptosis during wound healing. Hitherto, regulatory factors and pathways involved have been largely undefined. We investigated heterogeneity among fibroblasts derived from normal skin and keloid scar, by examining apoptotic profiles and pathways for these cells. Quantitative analysis of apoptotic cells using an Annexin‐V‐FITC binding assay showed that normal skin fibroblast cultures were found to have a two‐fold higher percentage of apoptotic cells than did keloid fibroblast cultures. To study apoptotic pathways and related death‐associated genes, a ribonuclease protection assay was performed for fibroblasts exposed to anti‐Fas antibody and tumor necrosis factor‐α to activate the Fas/TNF receptor apoptotic pathway. Compared with normal skin fibroblasts, keloid fibroblasts exhibited decreased expression of apoptosis‐associated genes.

Elevated Vascular Endothelial Growth Factor in Keloids: Relevance to Tissue Fibrosis

Excessive scar or keloid shares common features of a benign dermal growth. Yet, in contrast to malignant tumor, a keloid does not expand beyond the dermis. What triggers the continuing growth of a benign lesion? Deficient or overabundant levels of vascular endothelial growth factor have been reported to contribute to impaired or excessive wound healing. Although numerous studies have examined the pathophysiology of impaired wounds, little information has been provided on mechanisms of exuberant healing. The molecular basis of keloid formation is governed by the interplay of cellular signaling pathways, specific target gene activation, and the nature of the microenvironment. Recent works have demonstrated an accumulation of hypoxia-inducible factor-1α protein in freshly biopsied keloid tissues, thus providing first evidence that a local state of hypoxia exists in keloids. Our findings and the findings of others support at least two plausible mechanisms implicated in the development of fibrotic wounds, a state of ongoing fibroplasia or inflammation and an excessive accumulation of extracellular matrix. This article will review recent works examining the potential role of vascular endothelial growth factor in keloid pathogenesis with particular focus on its involvement in the two proposed pathological processes, a prolonged inflammation and an altered balance in extracellular matrix metabolism.

Screening for oral health literacy in an urban dental clinic

OBJECTIVE Studies show that the average person fails to understand and use health care related materials to their full potential. The goal of this study was to evaluate a health literacy instrument based on the Rapid Estimate of Adult Literacy in Medicine (REALM) that incorporates dental and medical terms into one 84-item Rapid Estimate of Adult Literacy in Medicine and Dentistry (REALM-D) measure and determine its association with patient characteristics of a culturally diverse dental clinic population. METHODS An 84-item dental/medical health literacy word list and a 48-item health beliefs and attitudes survey was provided to a sample of 200 adult patients seeking treatment for the first time at an oral diagnosis clinic located in a large urban medical center in Los Angeles, California. RESULTS Of the total sample, 154 participants read all of list 1 correctly, 141 read list 2 correctly, and only 38 read list 3 correctly. Nonwhite participants had significantly lower REALM-D scores at each level of difficulty as well as the total scale score compared to white participants. Participants who reported English as not their main language had significantly lower REALM-D scores. REALM-D scores also varied significantly by level of education among participants where as level of education increased, oral health literacy increased. At a bivariate level, race, education, and English as a main language remain predictive of health literacy in a regression model. An interaction between education and English as a main language was significant. CONCLUSIONS The REALM-D is an effective instrument for use by medical and dental clinicians in detecting differences among people of different backgrounds and for whom English was not their primary language.

Activation of NFκB signal pathways in keloid fibroblasts

Keloids are characterized as an “over-exuberant” healing response resulting in a disproportionate extracellular matrix (ECM) accumulation and tissue fibrosis. In view of the integral role of inflammation and cytokines in the healing response, it is logical to assume that they may play a part in orchestrating the pathology of this “abnormal” healing process. Tumor necrosis factor-α (TNF-α) is a potent proinflammatory cytokine involved in activation of signaling events and transcriptional programs, such as NFκB. This study attempts to determine the difference in NFκB and its related genes expression and DNA binding activity between keloid and normal skin fibroblasts. Three keloid and normal skin tissues (NSk) and their derived fibroblasts were used to determine NFκB signaling pathway expression using specific cDNA microarrays, Western blot analysis and immunohistochemistry. Electrophoretic mobility gel shift assay (EMSA) was used to assess NFκB-binding activity, all assays were performed in the presence and absence of TNF-α. TNF-α up-regulated 15% of NFκB signal pathway related genes in keloid fibroblast compared to normal skin. At the protein level, keloid fibroblasts and tissues showed higher basal levels of TNF- receptor–associated factors—TRAF1, TRAF2—TNF-α, inhibitor of apoptosis (c-IAP-1), and NFκB, compared with NSk. Keloid fibroblasts showed a constitutive increase in NFκB-binding activity in comparison to NSk both with and without TNF-α treatment. NFκB and its targeted genes, especially the antiapoptotic genes, could play a role in keloid pathogenesis; targeting NFκB could help in developing therapeutic interventions for the treatment of keloid scarring.

Aphthous ulcers: Aphthous ulcers

Aphthous ulcers are one of the most common oral diseases worldwide. Their clinical presentation is characterized by multiple, recurrent, small, round, or ovoid ulcers with circumscribed margins and erythematous haloes present in different sizes. Oral lesions similar to aphthous ulcers may be present in several systemic diseases. This article will summarize the differential diagnosis of aphthous ulceration, with emphasis on a practical guide for the management of recurrent aphthous ulceration, including topical and systemic therapy.