Yazan Hassona

Fibroblast gene expression profile reflects the stage of tumour progression in oral squamous cell carcinoma

Oral cancer is a highly aggressive malignancy with poor prognosis. This study examined the behaviour of fibroblast strains from normal oral mucosa, dysplastic epithelial tissue, and genetically stable (minimal copy number alterations—CNA; minimal loss of heterozygosity—LOH; wild‐type p53; wild‐type p16

Progression of genotype-specific oral cancer leads to senescence of cancer-associated fibroblasts and is mediated by oxidative stress and TGF-β.

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Senescent cancer-associated fibroblasts secrete active MMP-2 that promotes keratinocyte dis-cohesion and invasion

) and unstable (extensive CNA and LOH; inactivation of p53 and p16

Characterization of a Novel Oral Glucocorticoid System and Its Possible Role in Disease

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Oral potentially malignant disorders among dental patients: a pilot study in Jordan.

) oral squamous cell carcinoma (OSCC). Fibroblasts from genetically unstable OSCC relative to the other fibroblast subtypes grew more slowly and stimulated the invasion of a non‐tumourigenic keratinocyte cell line into fibroblast‐rich collagen gels. To understand these findings, genome‐wide transcriptional profiles were generated using the GeneChip® cDNA whole transcript microarray platform. Principal component analysis showed that the fibroblasts could be distinguished according to the stage of tumour development. Tumour progression was associated with down‐regulation of cell cycle‐ and cytokinesis‐related genes and up‐regulation of genes encoding transmembrane proteins including cell adhesion molecules. Gene expression was validated in independent fibroblast strains using qRT‐PCR. Gene connectivity and interactome‐transcriptome associations were determined using a systems biology approach to interrogate the gene expression data. Clusters of gene signatures were identified that characterized genetically unstable and stable OSCCs relative to each other and to fibroblasts from normal oral mucosa. The expression of highly connected genes associated with unstable OSCCs, including those that encode α‐SMA and the integrin α6, correlated with poor patient prognosis in an independent dataset of head and neck cancer. The results of this study demonstrate that fibroblasts from unstable OSCCs represent a phenotypically distinguishable subset that plays a major role in oral cancer biology. Copyright

Mouth cancer awareness and beliefs among dental patients

Keratinocyte senescence acts as a barrier to tumor progression but appears to be lost in late pre-malignancy to yield genetically unstable oral squamous cell carcinomas (GU-OSCC); a subset of OSCC possessing wild-type p53 and are genetically stable (GS-OSCC). In this study, fibroblasts from GU-OSCC were senescent relative to fibroblasts from GS-OSCC, epithelial dysplastic tissues or normal oral mucosa, as demonstrated by increased senescence-associated β-galactosidase (SA β-Gal) activity and overexpression of p16(INK4A). Keratinocytes from GU-OSCC produced high levels of reactive oxygen species (ROS) and this was associated with an increase in the production of transforming growth factor-β1 (TGF-β1) and TGF-β2 in stromal fibroblasts. Treatment of normal fibroblasts with keratinocyte conditioned media (CM) from GU-OSCC, but not GS-OSCC or dysplastic keratinocytes with dysfunctional p53, induced fibroblast senescence. This phenomenon was inhibited by antioxidants and anti-TGF-β antibodies. Fibroblast activation by TGF-β1 preceded cellular senescence and was associated with increased ROS levels; antioxidants inhibited this reaction. Senescent fibroblasts derived from GU-OSCC or normal fibroblasts treated with CM from GU-OSCC or hydrogen peroxide, but not non-senescent fibroblasts derived from GS-OSCC, promoted invasion of keratinocytes in vitro. Epithelial invasion was stimulated by fibroblast activation and amplified further by fibroblast senescence. The data demonstrate that malignant keratinocytes from GU-OSCC, but not their pre-malignant counterparts, produce high levels of ROS, which, in turn, increase TGF-β1 expression and induce fibroblast activation and senescence in a p5-independent manner. Fibroblasts from GU-OSCC were particularly susceptible to oxidative DNA damage because of high levels of ROS production, downregulation of antioxidant genes and upregulation of pro-oxidant genes. The results demonstrate the functional diversity of cancer-associated fibroblasts and show that malignant keratinocytes from GU-OSCC reinforce their malignant behavior by inducing fibroblast activation and senescence through ROS and TGF-β-dependent mechanisms.

A hyaluronic acid‐based compound inhibits fibroblast senescence induced by oxidative stress in vitro and prevents oral mucositis in vivo

Background:Previous studies have demonstrated that senescent cancer-associated fibroblasts (CAFs) derived from genetically unstable oral squamous cell carcinomas (GU-OSCC), unlike non-senescent CAFs from genetically stable carcinomas (GS-OSCC), promoted keratinocyte invasion in vitro in a paracrine manner. The mechanism by which this occurs is unclear.Methods:Previous work to characterise the senescent-associated secretory phenotype (SASP) has used antibody arrays, technology that is limited by the availability of suitable antibodies. To extend this work in an unbiased manner, we used 2D gel electrophoresis and mass spectroscopy for protein identification. Matrix metalloproteinases (MMPs) were investigated by gelatin zymography and western blotting. Neutralising antibodies were used to block key molecules in the functional assays of keratinocyte adhesion and invasion.Results:Among a variety of proteins that were differentially expressed between CAFs from GU-OSCC and GS-OSCC, MMP-2 was a major constituent of senescent CAF-CM derived from GU-OSCC. The presence of active MMP-2 was confirmed by gelatine zymography. MMP-2 derived from senescent CAF-CM induced keratinocyte dis-cohesion and epithelial invasion into collagen gels in a TGF-β-dependent manner.Conclusions:Senescent CAFs from GU-OSCC promote a more aggressive oral cancer phenotype by production of active MMP-2, disruption of epithelial adhesion and induction of keratinocyte invasion.

Dental students' knowledge and attitudes toward patients with epilepsy.

Synthetic corticosteroids are used widely for the treatment of a variety of diseases of the mouth. However, little is known as to whether the oral mucosa is able to modulate the local concentration of active corticosteroids or to produce steroids de novo. This has important clinical implications, because tissue-specific regulation of glucocorticoids is a key determinant of the clinical efficacy of these drugs. In the present study, we show that oral fibroblasts and keratinocytes expressed ACTH receptor (MC2R), glucocorticoid receptor (GR), and 11β-hydroxysteroid dehydrogenases (11β-HSDs). Unlike keratinocytes, fibroblasts lacked 11β-HSD2 and could not effectively deactivate exogenously administered cortisol. However, both cell types were able not only to activate cortisone into the active form cortisol, but also to synthesize cortisol de novo following stimulation with ACTH. 11β-HSD2, the enzyme controlling cortisol deactivation, exhibited different patterns of expression in normal (squamous epithelium and salivary glands) and diseased oral mucosa (squamous cell carcinoma and mucoepidermoid carcinoma). Blocking of endogenous cortisol catabolism in keratinocytes with the 11β-HSD2 inhibitor 18β-glycyrrhetinic acid mimicked the effect of exogenous administration of hydrocortisone and partially prevented the detrimental effects induced by pemphigus vulgaris sera. Analysis of the data demonstrates that a novel, non-adrenal glucocorticoid system is present in the oral mucosa that may play an important role in disease.

Cancer-associated fibroblasts regulate keratinocyte cell–cell adhesion via TGF-β-dependent pathways in genotype-specific oral cancer

BACKGROUND To determine the prevalence, types, and risk factors of oral potentially malignant disorders (OPMDs) among a group of Arab Jordanian dental patients, and to evaluate their awareness and attitudes toward early diagnosis and treatment. MATERIALS AND METHODS A total of 1,041 patients attending a University Hospital for dental care were examined for the presence of OPMDs. Histopathological examination was performed on all cases clinically diagnosed and patients were directly interviewed to evaluate their knowledge and attitudes toward early detection and treatment of oral cancer. RESULTS The prevalence of OPMDs overall was 2.8%. Lichen planus/lichenoid lesions were the most common lesions (1.8%) followed by leukoplakias (0.48%), chronic hyperplastic candidiosis (0.38%), and erythroplakia (0.096%). Smoking, alcohol, and age (>40 years) were the main identifiable risk factors. Patients with OPMDs displayed a general lack of awareness and negative attitudes towards early diagnosis and treatment. CONCLUSIONS OPMDs among Arab dental patients are relatively uncommon and awareness about oral cancer among Jordanian dental patients is low. Interventions to improve public knowledge about oral cancer and attitudes toward early diagnosis and treatment are urgently indicated.

Salivary changes in oral mucosal diseases

OBJECTIVES The aim of the present study was to assess the levels of awareness, knowledge about signs and risk factors of mouth (oral) cancer, and attitudes towards early diagnosis and treatment among dental outpatients. MATERIAL AND METHODS A total of 1,200 adult outpatients attending dental clinics at the University of Jordan Hospital for dental examination and treatment were randomly selected to participate in the study. An 18-item pretested close-ended questionnaire was used for the study. Descriptive statistics were generated and chi-square tests, t-tests, one-way analysis of variance (ANOVA), and Spearmans rho test were used to examine differences between groups. RESULTS Only 45.6% of the subjects had heard about oral cancer. Some 66.9% and 33.8%, respectively, were able to correctly identify tobacco and alcohol as risk factors. Some 24.1% had no knowledge about any signs of oral cancer. Male subjects, smokers, alcohol drinkers, older participants (>40 years), and participants with less than a university education were significantly less aware, and had much less knowledge, of the signs and risk factors of oral cancer (P<0.05). CONCLUSION Awareness about oral cancer among Jordanian dental outpatients is low. These dental patients, especially those in high-risk groups for mouth cancer and those of lower socio-economic status (SES), are less well informed about the signs and risk factors of oral cancer. Interventions to improve public knowledge about oral cancer and attitudes towards early diagnosis and treatment are urgently indicated.