Loss of Caveolin-1 Expression in Tumor Cells is Associated with Increased Aggressiveness and Cell Invasion in Oral Squamous Cell Carcinoma.

BACKGROUND: Changes in Caveolin-1 (CAV-1) expression are related to tumorigenesis. The aim of this study was to evaluate the role of CAV-1 in tumor progression in oral squamous cell carcinoma (SCC) tissue samples and the effect of CAV-1 silencing on two oral tongue SCC (OTSCC) cell lines (SCC-25, from a primary tumor, and HSC-3 from lymph node metastases). METHODS: Mycroarray hybridization, mRNA expression, and immunohistochemistry were performed on OSCC tissue samples and corresponding non-tumoral margin tissues. The effects of CAV-1 silencing (siCAV-1) on cell viability, membrane fluidity, on the expression of epithelial to mesenchymal transition (EMT) markers and on cell migration and invasion capacity of OTSCC cell lines were evaluated. RESULTS: Microarray showed a greater CAV-1 expression (1.77-fold) in OSCC tumors than in non-tumoral tissues and 2.0-fold more in less aggressive OSCCs. However, significant differences in CAV-1 gene expression were not seen between tumors and non-tumoral margins nor CAV-1 with any clinicopathological parameters. CAV-1 protein was localized both in carcinoma and in spindle cells of the tumor microenvironment (TME), and CAV-1 positive TME cells were associated with smaller/more aggressive tumors, independent of the carcinoma cells' expression. Silencing of CAV-1 increased cell viability only in SCC-25 cells. It also stimulated the invasion of HSC-3 cells and increased ECAD and BCAT mRNA in these cells; however, the protein levels of the EMT markers were not affected. CONCLUSION: Decreased expression of CAV-1 by tumor cells in OSCC and an increase in the TME were associated with increased cell invasiveness and tumor aggressiveness.

Cholesterol depletion affects caveolin-1 expression, migration and invasion of oral tongue squamous cell carcinoma cell lines.

INTRODUCTION: Cholesterol is a key lipid molecule within cell membranes. This is especially true in cavelolas, invaginated membrane nanodomains, which present the protein caveolin-1 (CAV-1). It is important to note that this structure is involved in many cell signalling pathways. Additionally, high cholesterol is seen in different tumor types but little is known in regards to oral tongue squamous cell carcinoma (OTSCC). The aim of this study was to evaluate the influence of cholesterol depletion on primary (SCC-25) and metastatic (HSC-3) OTSCC cell lines. MATERIALS AND METHODS: Cell membrane fluidity, cell viability, gene and protein expression of CAV-1 and of epithelial-mesenchymal transition (EMT) markers, cell migration in Myogel and invasion-myoma assay were evaluated after cholesterol depletion with methyl-ß-cyclodextrin (MßCD - 7.5, 10 or 15 mM) RESULTS: Decreased cell viability and increased membrane fluidity of SCC-25 cells was seen with cholesterol depletion but cell viability was less affected and there was no effect on membrane fluidity in HSC-3. Cholesterol depletion also decreased CAV-1 at 6 h but increased it after 24 h.; both epithelial and mesenchymal EMT genes were upregulated after 6 h, followed by downregulation at 24 h in SCC-25. In HSC-3, CAV-1 was downregulated, and E-cadherin gene (ECAD) was upregulated at 6 h. Only the protein ß-catenin in SCC-25 was affected, and cell migration of both cell lines was decreased, affecting SCC-25 more intensely. The invasive capacity within human myoma organotypic model was increased in SCC-25 and decreased in HSC-3. CONCLUSION: Cholesterol depletion affects CAV-1 and ECAD inversely. This affect also depends on cell type since the invasive capacity was augmented in primary cells while decreased in metastatic cells.

Differential protein expression of osteoclastogenic factors in odontogenic cysts and tumors.

The osteolytic activity of odontogenic cysts and tumors is directly associated with their growth and aggressiveness. The influence of proteins expressed by epithelial and mesenchymal cells on this biological event differs between indolent cystic lesions, aggressive cystic lesions, and odontogenic tumors. The objective of this study was to compare the immunohistochemical expression of factors that stimulate (receptor activator of nuclear factor kappa-Β ligand - RANKL, cathepsin K - CatK and matrix metallopeptidase 8 - MMP-8) and inhibit (osteoprotegerin - OPG) osteoclastogenesis between dentigerous cyst (DC), glandular odontogenic cyst (GOC), odontogenic keratocyst (OKC), and ameloblastoma (AB). Paraffin-embedded sections of nine DCs, nine GOCs, 20 OKCs, 21 ABs, and four dental follicles (DFs) were subjected to immunohistochemistry. Immunoreactivity was analyzed semiquantitatively and quantitatively in epithelium and connective tissue, respectively. The proteins were immunoexpressed in epithelial and mesenchymal cells of all lesions studied. The expression of RANKL and CatK was higher in OKC, AB, and GOC (p<0.005). Higher expression of OPG was found in DF and DC compared to the other markers (p<0.005). MMP-8 expression was high in GOC and OKC. This study demonstrated the differential expression of factors that inhibit and stimulate bone resorption during the development of DC, GOC, OKC, and AB. Higher expression of RANKL and CatK was observed in more aggressive lesions. OPG appears to be one of the molecules responsible for the slower growth of DC.

Mechanisms of immune evasion by head and neck cancer stem cells.

Different mechanisms are involved in immune escape surveillance driven by Oral and Head and Neck Cancer Stem Cells (HNCSCs). The purpose of this review is to show the most current knowledge regarding the main impact of HNCSCs on tumor evasion through immunosuppression, CSCs phenotypes and environmental signals, highlighting strategies to overcome immune evasion. The main results drive the participation of cell surface receptors and secreted products and ligands, the crosstalk between cells, and genetic regulation. The reduction in CD8+ T cell recruitment and decreased effector of anti-PD-1 therapy by cells expressing BMI1 is a key event; Natural Killer cell ligands and cytokines needed for its activation and expansion are crucial to control tumor growth and to target CSCs by immunotherapy; CSCs expressing ALDH1 are related to increased expression of PD-L1, with a positive link between DNMT3b expression; CD276 expression in CSCs can act as a checkpoint inhibitor and together with Activator Protein 1 (AP-1) activation, they create continuous positive feedback that enables immune evasion by suppressing CD8+ T cells and prevent immune cell infiltration in head and neck cancer. These data demonstrate the relevance of the better understanding of the interaction between HNCSCs and immune cells in the tumor microenvironment. The ultimate clinical implication is to ground the choice of optimized targets and improve immune recognition for ongoing treatments as well as the response to approved immunotherapies.

Florid cemento-osseous dysplasia-related osteonecrosis: A series of cases.

OBJECTIVE: The aim of this study was to assess the clinicopathological features of florid cemento-osseous dysplasia (FCOD)-related osteonecrosis highlighting their histopathological aspects and bone structure. METHODS: Twenty-two FCOD-related osteonecrosis cases were evaluated retrospectively. Osteonecrosis, osteomyelitis, bacterial colonization, bone resorption, reactive bone, osteon-like structure, lamellar bone, and basophilic lines were analyzed. Specific staining and fluorescence and polarized light microscopy analyses were also performed. RESULTS: The mandible was more affected by FCOD-related osteonecrosis. There was a predominance of African-Brazilian women in the fifth and seventh decades of life. Osteomyelitis was present in 82 % of cases whereas bone resorption and bacterial colonization were present in 100 % of FCOD-related osteonecrosis cases. Thick basophilic lines were seen in all cases (100 %). Actinomycosis and osteoclasts were not often. CONCLUSIONS: This study showed female adult preference, mandibular location, and some findings such as osteomyelitis, bone resorption, and bacterial colonization were histopathological features more frequent in FCOD-related osteonecrosis. In the absence of a close clinical and radiographic correlation, the morphology of the necrotized bone similar to cementum could help to recognize FCOD.

Oral manifestations of multisystemic inflammatory syndrome in children (MIS-C) and Kawasaki disease associated to COVID-19: A systematic review.

AIMS: Multisystemic inflammatory syndrome in children (MIS-C) is a condition noted in some children asymptomatic but positive to Sars-cov-2 antibody and it presents clinical and laboratory changes similar to Kawasaki disease (KD). Oral changes have also been observed. This systematic review evaluated oral manifestations detected in children with MIS-C and KD associated to COVID-19. METHODS AND RESULTS: This work was registered at PROSPERO (#CRD42020225909), following PRISMA guidelines. A comprehensive research was conducted in MEDLINE, Web of Science, EMBASE, LILACS, Scopus, and Grey Literature through August 2021, based on original research evaluating children diagnosed with MIS-C or KD related to COVID-19. Two authors independently screened all retrieved references. Twenty five selected studies evaluated 624 children, mean age 8.78 years. The assessment of the risk of bias (ROB) showed that most of them presented low ROB. Oral manifestations were erythematous mucous membrane, oral ulcers lesions, dry, swollen and cracked lips, and strawberry tongue. CONCLUSION: MIS-C and KD share the same oral manifestations and their identification may lead to an early diagnosis.

Differential protein expression of osteoclastogenic factors in odontogenic cysts and tumors

Abstract: The osteolytic activity of odontogenic cysts and tumors is directly associated with their growth and aggressiveness. The influence of proteins expressed by epithelial and mesenchymal cells on this biological event differs between indolent cystic lesions, aggressive cystic lesions, and odontogenic tumors. The objective of this study was to compare the immunohistochemical expression of factors that stimulate (receptor activator of nuclear factor kappa-Β ligand - RANKL, cathepsin K - CatK and matrix metallopeptidase 8 - MMP-8) and inhibit (osteoprotegerin - OPG) osteoclastogenesis between dentigerous cyst (DC), glandular odontogenic cyst (GOC), odontogenic keratocyst (OKC), and ameloblastoma (AB). Paraffin-embedded sections of nine DCs, nine GOCs, 20 OKCs, 21 ABs, and four dental follicles (DFs) were subjected to immunohistochemistry. Immunoreactivity was analyzed semiquantitatively and quantitatively in epithelium and connective tissue, respectively. The proteins were immunoexpressed in epithelial and mesenchymal cells of all lesions studied. The expression of RANKL and CatK was higher in OKC, AB, and GOC (p<0.005). Higher expression of OPG was found in DF and DC compared to the other markers (p<0.005). MMP-8 expression was high in GOC and OKC. This study demonstrated the differential expression of factors that inhibit and stimulate bone resorption during the development of DC, GOC, OKC, and AB. Higher expression of RANKL and CatK was observed in more aggressive lesions. OPG appears to be one of the molecules responsible for the slower growth of DC.

Homeobox gene amplification and methylation in oral squamous cell carcinoma.

OBJECTIVES: Investigate the DNA copy number and the methylation profile of the homeobox genes HOXA5, HOXA7, HOXA9, HOXB5, HOXB13, HOXC12, HOXC13, HOXD10, HOXD11, IRX4 and ZHX1, and correlate them with clinicopathological parameters and overall survival. MATERIAL AND METHODS: DNA from OSCC samples and surgical margins were submitted to DNA amplification by qPCR and to DNA methylation analysis using a DNA Methylation PCR Array System. RESULTS: HOXA5, HOXB5 and HOXD10 were amplified in surgical margins while HOXA9, HOXB13 and IRX4 were amplified in OSCC. HOXD10 demonstrated hypermethylation in half of the tumor while ZHX1 did not show hypermethylation. No correlation of DNA copy number or methylation with clinicopathological parameters or survival was observed. CONCLUSION: HOXA9, HOXB13 and IRX4 genes appears to be regulated by amplification and HOXD10 by methylation in OSCC. Further studies are needed to determine the role of these events in OSCC development.

Central giant cell granuloma: A clinicopathological and immunohistochemical study of macrophages, blood vessels, lymphatic vessels and regulatory proteins.

OBJECTIVE: This study seeks to investigate immunohistochemical parameters that could distinguish non-aggressive Central giant cell granuloma (CGCG) from aggressive CGCG, two groups of lesions which differ in their clinical and radiographic features and prognosis. MATERIAL AND METHODS: 12 cases of non-aggressive CGCG and 11 cases of aggressive CGCG were investigated and associated the immunohistochemical expression of macrophages (CD68 and CD163), blood vessels (CD34 and CD105), lymphatic vessels (D2-40) and regulator proteins (p63 and Ki-67). Clinical and radiographic features were also studied. RESULTS: Associations between all proteins in non-aggressive and aggressive CGCG were not significant (p > 0.05). With respect to non-aggressive CGCG, there were no significant correlations, while in aggressive CGCG there was a significant positive correlation between CD68 and CD163 (p = 0.031), between CD34 and D2-40 proteins (p = 0.04), whereas a significant negative correlation was observed between CD105 and CD68 (p = 0.040). However, regardless of aggressiveness of CGCG, there was a significant positive correlation between CD68 and CD163 (p = 0,04). Among the clinical and immunohistochemical aspects, only the symptomatology was a significant risk factor for the occurrence of aggressive CGCG (OR = 12.00/p = 0.016). CONCLUSION: Macrophages and angiogenesis contribute to their maintenance and development of CGCG. In addition, immunohistochemistry used here was not able to differentiate their aggressiveness. However, symptomatology was proved to be a risk factor for the occurrence of aggressive CGCG. It is possible that clinical features, particularly symptomatology, represent the most appropriate parameter to attempt to distinguish GCCG.

Subcellular localization and expression of E-cadherin and SNAIL are relevant since early stages of oral carcinogenesis.

The biological process of epithelial-to-mesenchymal transition (EMT) has been studied in oral squamous cell carcinoma (OSCC) metastasis, but it is rarely evaluated at several stages of oral carcinogenesis. This study aimed to analyze the presence of SNAIL and E-cadherin proteins, markers of EMT, in the development and progression of OSCC, evaluating excised specimens of potentially malignant lesions (oral leukoplakia with and without dysplasia-OL and OLD, respectively), tumor tissues (OSCC), metastatic lymph nodes (LN), and normal oral mucosa (NOM) by immunohistochemistry, considering subcellular localization. Additionally, SNAIL and E-cadherin transcripts were evaluated in vitro by qPCR, using SCC-9 cell line in comparison to human keratinocytes (HPEC). There was a significant increase in nuclear expression of SNAIL from NOM to OLD followed by a noticeable decrease in nuclear expression accompanied by increased cytoplasmic expression in OSCC (p<0.05). The E-cadherin cytoplasmic expression was remarkable and statistically significant higher in OSCC and LN, both compared to NOM (p< 0.0001), OL (p<0.01) and OLD (p< 0.0001 and p<0.001, respectively). In vitro, E-cadherin and SNAIL transcripts were lower in SCC-9 compared to HPEC cells, although only the decrease of E-cadherin was statistically significant (p<0.05). Regarding the association of E-cadherin and SNAIL expression with the clinical findings, the analysis revealed an association between the cytoplasmic expression of SNAIL and the invasion pattern (p=0.05) in OSCC. The increased nuclear SNAIL expression may be characteristic of OLD, and the presence of E-cadherin in cell cytoplasm a marker of transformation to malignancy of potentially malignant oral leukoplakias into OSCC.

MicroRNAs expression pattern related to mast cell activation and angiogenesis in paraffin-embedded salivary gland tumors.

The aim of this study was evaluate the expression profile of microRNAs related to mast cells activation and angiogenesis in salivary glands tumors. METHOD: We have analyzed the expression of miR-9, miR-16, miR-17, miR-132, miR-195 and miR-221 by real-time RT-PCR, in 11 adenoid cystic carcinomas, 9 mucoepidermoid carcinomas and 11 pleomorphic adenomas. Immunohistochemical investigation was performed to detect mast cells tryptase and CD-34 for microvessels biomarkers. miR-16, miR-17, miR-132, miR-195 and miR-221 showed a decreased expression, whereas miR-9 showed an increased expression in most cases compared to normal tissues. However, in all tumors studied only miR-9 showed a statistical significant negative correlation with microvessel density (p=0.001). It was observed a higher density of mast cells in mucoepidermoid carcinomas (10.55 cells/mm2) when compared to adenoid cystic carcinomas (6.27 cells/mm2) and between mucoepidermoid carcinomas and pleomorphic adenomas (5.97células/mm2). miR-17, miR-132, miR-195 and miR-221 seem to play an important role as tumor suppressor in salivary gland tumors. In addition, the significant correlation between mast cell and microvessel density contributes to the growth and pathogenesis of these tumors and they may become strong therapeutic targets in the future.

Does laser phototherapy influence the proliferation of myoepithelial cells in the salivary gland of hypothyroid rats?

Thyroid hormones influence both development and growth of organs and tissues and guarantee metabolic demands that interfere with the quality of digestive secretions, including those of the salivary glands. Laser phototherapy - LPT can modulate various biological phenomena and its diverse effects permit the action on different cell types. The aim of this study was to evaluate the influence of laser phototherapy on myoepithelial cells of salivary glands of hypothyroid rats. Forty-two albino Wistar rats were divided into two main groups: euthyroid (EU) and hypothyroid (HYPO). Hypothyroidism was induced using propylthiouracil (PTU) for 4weeks. Each group was divided into subgroups: control (without laser) and laser groups (Red/infrared - IR). LPT was used on the submandibular gland and was carried out using a diode laser (λ660 or λ780nm, 40mW, spot size 0.04cm2, irradiation area 1cm2, 300s, 6J/cm2 per gland, 12J/cm2 per session) and started two weeks after PTU treatment. LPT was repeated every other day for two weeks. After animal death, the glands were removed, dissected and processed for immunohistochemical analysis. It was observed an increase in the number of myoepithelial cells of hypothyroid control rats in comparison to euthyroid controls (p=0.001). Visible LPT (λ660nm) caused significant higher proliferation of myoepithelial cells in EU rats when compared to IR LPT (λ 780nm)(p≤0.001).It is concluded that, despite the LPT protocol used did not influence myoepithelial proliferation on hypothyroid rats it significantly increased the proliferation on euthyroid animals.

Methylation status of homeobox genes in common human cancers.

Approximately 300 homeobox loci were identified in the euchromatic regions of the human genome, of which 235 are probable functional genes and 65 are likely pseudogenes. Many of these genes play important roles in embryonic development and cell differentiation. Dysregulation of homeobox gene expression is a frequent occurrence in cancer. Accumulating evidence suggests that as genetics disorders, epigenetic modifications alter the expression of oncogenes and tumor suppressor genes driving tumorigenesis and perhaps play a more central role in the evolution and progression of this disease. Here, we described the current knowledge regarding homeobox gene DNA methylation in human cancer and describe its relevance in the diagnosis, therapeutic response and prognosis of different types of human cancers.

Involvement of mast cells and microvessels density in reactive lesions of oral cavity: A comparative immunohistochemical study.

In view of the similarity of clinicopathological features between reactive lesions of the oral cavity, the objective of the present study was to investigate the density of MCs (mast cells) and microvessels in a series of these lesions. Thirty-seven cases of reactive lesions including fibrous hyperplasia (FH, n=10), inflammatory fibrous hyperplasia (IFH, n=10), peripheral giant cell lesion (PGCL, n=10) and lobular capillary hemangioma (LCH, n=7) were investigated using immunohistochemistry for mast cell tryptase and CD34. For comparative purposes, central giant cell lesions (CGCL, n=5) were included. A higher MC density was observed in LCH (37.01), while CGCL exhibited the lowest density (n=8.14). There was a significant difference in MC density when all reactive lesions were compared to CGCL (p=0.001). The largest mean density of microvessels was observed in LCH (n=21.69). The smallest number was observed in CGCL (n=6.24). There was a significant difference in microvessel density when the reactive lesions were compared to CGCL (p=0.003). There was a significant and direct correlation between the density of MCs and microvessels only for IFH (p=0.048) and CGCL (p=0.005). A significant and direct correlation between the mean density of MCs and microvessels was observed when the reactive lesions were analyzed as a whole (p=0.005). Our results suggest that mast cells contribute to the connective tissue framework and angiogenic function, as well as the development, of reactive lesions of the oral cavity, including FH, IFH, LCH and PGCL.

Laser phototherapy improves early stage of cutaneous wound healing of rats under hyperlipidic diet.

The aim of this study was to evaluate the influence of laser photobiomodulation in cutaneous healing of rats under a hyperlipidic diet. Forty-eight Wistar Albinus rats, weaned, received standard diet (SD) or hyperlipidic diet (HD) for 20 weeks. The groups were divided into SD rats and HD rats, SD-irradiated rats (LSD), and HD-irradiated rats (LHD). Standard cutaneous wound (1 cm(2)) was created on the dorsum of each rat. The irradiation started immediately after surgery and every 48 h for 7 or 14 days (λ660 nm, 40 mW, 6 J/cm(2), ϕ 0,04 cm(2), CW), when they were killed under deep anesthesia. The specimens were removed, routinely processed, stained with hematoxylin/eosin (H/E), and evaluated by light microscopy. Rats fed with hyperlipidic diet had greater intensity in the inflammatory process and prolonged hyperemia. At day 7, the intensity of inflammation was reduced in LSD and LHD groups when compared to their control groups, SD (p = 0.002) and HD (p = 0.02). There was an increase in fibroblast proliferation and collagen deposition, especially in the LHD group. At day 14, the HD group presented more intensive hyperemia than the SD group. It can be concluded that the hyperlipidic diet modified the inflammation pattern in wound healing and that laser light has a positive biomodulative effect on the healing process only in early stages.

Interaction of stromal and microvascular components in keratocystic odontogenic tumors.

OBJECTIVE: Little is known about the interaction of stromal components in odontogenic tumors. Thus, the aim of this study was to investigate mast cells (MCs), myofibroblasts, macrophages, and their possible association with angiogenesis and lymphangiogenesis in keratocystic odontogenic tumors (KCOTs). MATERIAL AND METHODS: Thirty cases of KCOTs were included and analyzed by immunohistochemistry for mast cell tryptase, α-SMA, CD34, CD163, and D240. For comparative purpose, 15 radicular cysts (CRs) and 7 pericoronal follicles (PFs) were included. RESULTS: There was an increase in MCs for RCs and this difference was significant when they were compared to KCOTS and PFs. A significant increase in the density of MFs was observed for KCOTs when compared to RCs and PFs (P = 0.00). No significant difference in CD163-positive macrophages (P = 0.084) and CD34-positive vessels (P = 0.244) densities was observed between KCOTs, RCs, and PFs, although KCOTs showed a higher density of all proteins. Significant difference in lymphatic vessel density was observed for KCOTs when compared to RCs and PFs (P = 0.00). Positive correlation was observed between mast cell tryptase and CD34 in KCOTs (P = 0.025). CONCLUSIONS: A significant interaction between the MC population and CD34-positive vessels in KCOTs supported the hypothesis that MCs and blood vessels contribute to the stromal scaffold of KCOT.

Useful histological findings in incisional biopsies of oral squamous cell carcinoma.

Introduction: Oral squamous cell carcinoma (OSCC) is one of the most common head and neck cancers. Objective: The aim of this study was to investigate the histopathological features of OSCC specimens obtained from incisional biopsies and to alert clinicians to the importance of more representative biopsies. Methods: Forty-eight OSCC samples were obtained from incisional biopsies and classified by Bryne's score. The following morphological features were analyzed: invasive front, invasiveness, apoptotic cells, atypical mitosis, giant cells, acantholysis, ulceration, necrosis, calcification, surface epithelium, granulation tissue, desmoplasia, tissue invasions, inflammatory infiltrate and tumor thickness. Results: Ten (21%) cases were classified as high grade malignancies and 38 (79%) as low grade. Apoptotic cells (n = 26), atypical mitosis (1­2/20×; n = 38), giant cells (n = 8), acantholysis (n = 5), necrosis (n = 5), calcification (n = 1), granulation tissue (n = 32), desmoplasia (n = 4), perineural invasion (n = 2), muscular invasion (n = 8), invasion of salivary gland tissue (n = 3), vascular invasion (n = 10), and chronic inflammation (n = 33) were observed. Vascular invasion (p = 0.04, Pearson's χ2 test) and necrosis (p = 0.04, Pearson's χ2 test) were significantly associated with cases of high-grade malignant tumors. Atypical mitosis was associated with a greatest tumor thickness (p = 0.04, Fischer's exact test). Conclusion: This study suggests that incisional biopsies may be useful and significant as they can show histopathological variables that are important to classify oral squamous cell carcinomas into low grade and high grade according to Bryne's score, which was used in this study. Thus, more representative biopsies might be useful to achieve this and allow a more accurate planning.

E-cadherin regulators are differentially expressed in the epithelium and stroma of keratocystic odontogenic tumors.

BACKGROUND: The epithelial-mesenchymal transition (EMT) is the process where cells lose their epithelial features and acquire properties of typical mesenchymal cells. The dissociation of tumor cells due to changes in cell-cell adhesion is one of the key principles of tumor invasion and EMT. Thus, the knowledge of the molecular features of EMT in keratocyst odontogenic tumor (KOT) can provide useful markers to aid in the diagnosis and prognosis and perhaps contribute to an alternative therapeutic approach as it shows an aggressive clinical behavior and high recurrence rates. This study aimed to evaluate the EMT in KOT by the immunoexpression of E-cadherin, N-cadherin, Snail, and Slug and comparing to radicular cysts and dental follicles. METHODS: Thirty-two KOTs, 15 radicular cysts, and 08 dental follicles were used for immunohistochemistry, evaluating the extent, intensity, labeling pattern, cellular compartment in the epithelium and stroma, and the presence of inflammation. RESULTS: E-cadherin was preserved in most cases of keratocystic odontogenic tumor. N-cadherin was increased in the tumor epithelium, a result that was positively correlated with the heterogeneous and nuclear immunoexpression of Slug in the epithelium; Slug also correlated with high Snail immunoexpression. N-cadherin was positively correlated with Slug in the stroma of keratocystic odontogenic tumors. CONCLUSIONS: The high immunoexpression of Snail and nuclear Slug in keratocystic odontogenic tumors suggests these proteins as transcription factors without necessarily participating in 'cadherin switching'. However, the knowledge of their induction of the epithelial-mesenchymal transition in odontogenic tumors is still limited.

Epigenetic repression of HOXB cluster in oral cancer cell lines.

OBJECTIVE: Aberrant DNA methylation is a fundamental transcriptional control mechanism in carcinogenesis. The expression of homeobox genes is usually controlled by an epigenetic mechanism, such as the methylation of CpG islands in the promoter region. The aim of this study was to describe the differential methylation pattern of HOX genes in oral squamous cell carcinoma (OSCC) cell lines and transcript status in a group of hypermethylated and hypomethylated genes. DESIGN: Quantitative analysis of DNA methylation was performed on two OSCC cell lines (SCC4 and SCC9) using a method denominated Human Homeobox Genes EpiTect Methyl qPCR Arrays, which allowed fast, precise methylation detection of 24 HOX specific genes without bisulfite conversion. RESULTS: Methylation greater than 50% was detected in HOXA11, HOXA6, HOXA7, HOXA9, HOXB1, HOXB2, HOXB3, HOXB4, HOXB5, HOXB6, HOXC8 and HOXD10. Both cell lines demonstrated similar hypermethylation status for eight HOX genes. A similar pattern of promoter hypermethylation and hypomethylation was demonstrated for the HOXB cluster and HOXA cluster, respectively. Moreover, the hypermethylation profile of the HOXB cluster, especially HOXB4, was correlated with decreased transcript expression, which was restored following treatment with 5-aza-2'-deoxycytidine. CONCLUSIONS: The homeobox methylation profile in OSCC cell lines is consistent with an epigenetic biomarker.

Effect of laser phototherapy (λ660 nm) on type I and III collagen expression during wound healing in hypothyroid rats: an immunohistochemical study in a rodent model.

OBJECTIVE: The aim of this study was to assess, immunohistochemically, the impact of hypothyroidism and the effect of laser phototherapy on the expression of type I and III collagen during wound healing. BACKGROUND DATA: Hypothyroidism has been associated with the disruption of the body's metabolism, including the healing process. Laser phototherapy has been shown to be effective in improving wound healing, but its usefulness on enhancing wound healing under hypothyroid condition remains unknown. MATERIALS AND METHODS: Using general anesthesia, a standard surgical wound (1 cm(2)) was created on the dorsa of 48 Wistar rats divided into four groups of 12 animals each: control euthyroid (EC), euthyroid plus laser (EL), control hypothyroid (HC), and hypothyroid plus laser (HL). The irradiation with laser GaAlAs [λ660 nm, 40 mW, 1 W/cm(2), continuous wave (CW), ø=0.04 cm(2)] started immediately after surgery and was repeated every other day until end-point of study was reached, and animals were euthanized (i.e., 7 and 14 days). Laser light was applied on four different points (6 J, 150 sec and 150 J/cm(2) per point). Hypothyroidism was induced in rats with propylthiouracil (0.05 g/100 mL) administered orally for 4 weeks and maintained until the end of the experiment. Immunohistochemistry for collagen I and III was performed with EnVision(™) in the specimens removed. RESULTS: Seven days after the surgery EC, EL, and HL groups showed higher immunoexpression of collagen I and lower immunoexpression of collagen III in the newly formed tissue. There was increased immunoexpression of collagen I in EC when compared with HC (p=0.019). The immunoexpression of collagen III was significantly lower in EL than in EC (p=0.047) and HL (p=0.019). No significant difference was found in the experimental period of 14 days among the groups. CONCLUSIONS: Laser light therapy performed with the parameters of this investigation increased immunoexpression of collagen type I during tissue repair, and improved the quality of newly formed tissue in the presence of hypothyroidism.