Molecular Modeling Analysis Provides Genotype-Phenotype Correlation Insights in a Patient with Ankyloblepharon-Ectodermal Dysplasia-Clefting Syndrome.

Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome is a rare autosomal dominant disorder. AEC is caused by mutations in the TP63 gene that encodes the tumor suppressor p63 protein, itself involved in the regulation of epidermal proliferation, development, and differentiation. We present here a typical AEC case of a four-year-old girl with extensive skin erosions and erythroderma of the scalp and the trunk, and to a lesser extent of the limbs, nail dystrophy on the fingers and toes, xerophthalmia, a high-arched palate, oligodontia, and hypohidrosis. Mutation analysis of the TP63 gene detected a de novo missense mutation in exon 14 (c.1799G>T; p.Gly600Val). We discuss the phenotype-genotype correlation by presenting the clinical features of AEC in the patient, and the effect of the detected mutation in p63 structure and function using protein structural modeling, in view of similar cases in the literature. We performed a molecular modeling study in order to link the effect on the protein structure level of the missense mutation G600V. We noted that the introduction of the bulkier Valine residue in place of the slim Glycine residue caused a significantly altered 3D conformational arrangement of that protein region, pushing away the adjacent antiparallel α helix. We propose that the introduced locally altered structure of the G600V mutant p63 has a significant functional effect on specific protein-protein interactions, thus affecting the clinical phenotype.

Enhancement of erbB2 and erbB3 expression during oral oncogenesis in diabetic rats.

PURPOSE: The expression of erbB2 and erbB3 receptors was investigated in an experimental model of chemically induced oral carcinogenesis in normal and diabetic (type I) Sprague-Dawley rats. METHODS: Thirteen diabetic and twelve normal rats developed precancerous and cancerous lesions after 4-nitroquinoline-N-oxide treatment, while six diabetic and six normal animals were used as controls. Sections of biopsies from all animals were classified histologically in the following categories: normal mucosa, hyperplasia, dysplasia, early invasion, well- and moderately-differentiated squamous cell carcinoma. Each section was studied immunohistochemically using monoclonal antibodies against erbB2 and erbB3 proteins and six representative histological regions in each section were analysed. RESULTS: The erbB2 was expressed at very low levels in normal rats, while in diabetic animals its expression was significantly increased during early invasion (P = 0.04). The erbB3 expression was significantly elevated in well-differentiated carcinoma in normal animals (P = 0.01), while in diabetic animals it was significantly increased during oral mucosal hyperplasia and dysplasia (P = 0.03 and 0.0007, respectively). The comparison of erbB2 expression between diabetic and normal rats revealed significant differences in all stages except for the tumor stage of moderately differentiated carcinoma (P = 0.01, 0.00001, 0.00001, 0.003, and 0.00001). In regard to erbB3 expression, significant differences between diabetic and normal rats existed only in normal, non-cancerous and precancerous stages (P = 0.007, 0.0001, 0.0003). CONCLUSIONS: It seems that diabetes enhances the expression of both erbB2 and erbB3 in certain stages of oral oncogenesis possibly resulting in promotion of cell proliferation and inhibition of apoptosis.

Expression of cell cycle regulator p16 is not affected by diabetes during oral oncogenesis.

BACKGROUND: The tumor suppressor protein p16 plays a vital role in the regulation of the cell cycle. The expression of p16 was investigated in an experimental model of chemically induced carcinogenesis in normal and diabetic (type I) Sprague-Dawley rats. MATERIALS AND METHODS: Tissue sections ranging from normal oral mucosa to moderately differentiated oral squamous cell carcinoma (OSCC) were studied immunohistochemically. RESULTS: In normal rats p16 expression increased gradually during oral oncogenesis, but a significant increase was observed only in moderately differentiated OSCC (p=0.038). On the contrary, in diabetic rats the detected gradual increase was significant in hyperplasia, dysplasia, early invasion and well-differentiated OSCC (p<0.001). Nevertheless, there was no significant difference in p16 expression during oral oncogenesis between normal and diabetic animals. CONCLUSION: It seems that the expression of cell cycle regulator p16 is not affected by diabetes in the studied animal model of oral oncogenesis.

Evaluation of apoptosis in nasal and buccal cells of septic patients.

BACKGROUND: Inhibition of lung cell apoptosis in the bronchoalveolar lavage (BAL) of septic patients may have a prognostic value for the severity of sepsis. The present study evaluated apoptosis in the nasal and buccal mucosa of septic patients as an alternative and less invasive approach for studying the cells involved in bronchial inflammation. PATIENTS AND METHODS: A prospective study was designed. Nasal and buccal mucosa brushings were obtained from 20 consecutive septic patients who were admitted to two intensive care units. Twenty-four patients scheduled to undergo surgery for colorectal cancer or laparascopic cholocystectomy were the control group. Apoptosis was evaluated using a TUNEL assay, while BCL-2 and BAX expression were evaluated by immunohistochemistry. RESULTS: Significantly reduced apoptosis in the nasal mucosa of septic patients compared to the control group (p=0.043) was detected only by the TUNEL assay. CONCLUSION: Reduced apoptosis was found during sepsis in the nasal mucosa in accordance with the reduced apoptosis in the lungs of septic patients. In contrast to septic lungs the underlying mechanism leading to apoptosis in the nasal mucosa was unrelated to the expression of two apoptosis-related genes BCL-2 and BAX.

Increased risk of oral cancer in diabetic animals is not associated with c-jun activation pathway.

PURPOSE: The expression of oncogenic protein c-jun was investigated in an experimental model of chemically induced carcinogenesis in normal and diabetic (type I) Sprague-Dawley rats. MATERIAL AND METHODS: Thirteen diabetic and twelve normal rats developed cancer after 4-nitroquinoline-N-oxide treatment, while six diabetic and six normal animals were used as controls. The biopsies were classified pathologically from oral mucosal dysplasia to moderately differentiated oral squamous cell carcinoma (OSCC) and studied immunohistochemically using monoclonal antibody against c-jun protein. RESULTS: Higher c-jun levels were observed in non-cancerous and precancerous stages of normal rats compared with diabetic rats, while in different tumour stages, the expression of c-jun was practically identical for both groups. CONCLUSION: It seems that diabetes does not affect the c-jun N-terminal kinase (JNK)/c-jun pathway.

Diabetes increases both N-ras and ets-1 expression during rat oral oncogenesis resulting in enhanced cell proliferation and metastatic potential.

BACKGROUND: The expression of N-ras and ets-1 proteins was investigated in an experimental model of chemically-induced carcinogenesis in normal and diabetic (type I) Sprague-Dawley rats. MATERIALS AND METHODS: Tissue sections ranging from normal mucosa to moderately-differentiated oral squamous cell carcinoma were studied using monoclonal antibodies against N-ras and ets-1 proteins. RESULTS: In diabetic rats, N-ras expression increased with tumor advancement, while in normal rats N-ras was not detected in initial stages of oral oncogenesis and increased only in well-differentiated OSCC. The same pattern of elevated ets-1 expression was observed both in diabetic and normal rats, but in cancerous stages this expression was higher in diabetic than in normal rats. CONCLUSION: It seems that diabetes may contribute to increased cell proliferation due to N-ras constitutive activation, as well as to enhanced invasion and metastatic potential by increasing ets-1 levels.

Diabetes does not influence oral oncogenesis through fibroblast growth factor receptors.

BACKGROUND: Increased expression of fibroblast growth factors and their receptors (FGFRs) has recently been described in oral squamous cell carcinoma. In addition, we have previously described a molecular basis for an association between oral cancer and diabetes. The expression of FGFR-2 and FGFR-3 investigated in an experimental model of chemically induced carcinogenesis in normal and diabetic (type I) rats. MATERIALS AND METHODS: Tissue sections ranging from normal mucosa to moderately-differentiated oral squamous cell carcinoma were studied using monoclonal antibodies against FGFR-2 and FGFR-3 proteins. RESULTS: A similar pattern of elevated FGFR-2 and FGFR-3 expression was observed in the initial stages of oncogenesis for both diabetic and non-diabetic animals. In the last stages of oral oncogenesis, the expression of both proteins remained relatively stable. CONCLUSION: It seems that diabetes does not affect the FGFR-2 and FGFR-3 pattern of expression throughout the various stages of oral oncogenesis.

Diabetes alters expression of p53 and c-myc in different stages of oral oncogenesis.

BACKGROUND: The expression of tumour suppressor p53 and oncogene c-myc was investigated in an experimental model of chemically induced carcinogenesis in normal and diabetic (type I) Sprague-Dawley rats. MATERIALS AND METHODS: Tissue sections ranging from normal mucosa to moderately differentiated oral squamous cell carcinoma were studied using monoclonal antibodies against mutant p53 and c-myc proteins. RESULTS: From hyperplasia to later stages of oral oncogenesis, mutant p53 expression was at higher levels in diabetic rats in comparison to normal animals, although the pattern of expression was similar. In contrast, c-myc expression was significantly higher in diabetic than in normal rats only in normal mucosa and hyperplasia. CONCLUSION: It seems that diabetes contributed to increased accumulation of mutations in the p53 gene, contributing to increased proliferation of tumour cells during oral oncogenesis. Additionally, diabetes appeared to enhance c-myc expression only in the initial stages of oral oncogenesis.

Diabetes and oral oncogenesis.

Oral squamous cell carcinoma (OSCC) is the sixth most common malignancy in humans including type I diabetic and normal rats. Tobacco and alcohol, as well as dysregulation of oncogenes and tumor suppressor genes, epigenetic changes and mitochondrial mutations have been implicated in OSCC development. Recent epidemiological studies have incriminated diabetes mellitus as a risk factor for the development of OSCC, as well as oral premalignant lesions. Recently, an animal model was employed to study the influence of diabetes on signal transduction pathways in every stage of oral cancer development, from normal mucosa to hyperplasia, dysplasia, early invasion, well differentiated OSCC and moderately differentiated OSCC. Diabetes was induced by streptozotocin and chemical carcinogenesis was induced by the carcinogen 4-nitroquinoline N-oxide. The expression of EGFR, erbB2, erbB3, FGFR-2, FGFR-3, c-myc, N-ras, ets-1, H-ras, c-fos and c-jun, the tumor suppressor genes p53 and p16, apoptosis markers Bax and Bcl-2, and the cell proliferation marker Ki-67 in the sequential stages of rat oral oncogenesis was investigated. Diabetes seems to promote the activation of the Ras/Raf/MAPK signal transduction pathway mainly by induction of erbB2 and erbB3 receptors, leading to increased cell proliferation, while there was no difference in apoptosis levels during oncogenesis.