αTAT1-induced tubulin acetylation promotes ameloblastoma migration and invasion.

Ameloblastoma (AB) is the most common benign epithelial odontogenic tumor occurring in the jawbone. AB is a slowly growing tumor but sometimes shows a locally invasive and an aggressive growth pattern with a marked bone resorption. In addition, the local recurrence and distant metastasis of AB also sometimes occurs, which resembles one of the typical malignant potentials. From these points of view, to understand better the mechanisms of AB cell migration or invasion is necessary for the better clinical therapy and improvements of the patients' quality of life. Microtubules in eukaryotic cells reveal the shape of hollow cylinders made up of polymerized alpha (α)- and beta (ß)-tubulin dimers and form the cytoskeleton together with microfilaments and intermediate filaments. Microtubules play important roles in cell migration by undergoing assembly and disassembly with post-translational modifications. Stability of microtubules caused by their acetylation is involved in cell migration. In this study, we investigated the expression and distribution of acetylated α-tubulin and alpha-tubulin N-acetyltransferase 1 (αTAT1), an enzyme which acetylates Lys-40 in α-tubulin, in AB specimens, and analyzed how tubulin was acetylated by αTAT1 activation in a human AB cell line, AM-1. Finally, we clarified that TGF-ß-activated kinase1 (TAK1) was phosphorylated by TGF-ß stimulation, then, induced tubulin acetylation via αTAT1 activation, which subsequently activated the migration and invasion of AB cells.

Differential expression of nicotinamide N-methyltransferase in primary and recurrent ameloblastomas and odontogenic keratocysts.

BACKGROUND: Odontogenic tumours are a group of rare heterogeneous diseases that range from hamartomatous tissue proliferations to benign and malignant neoplasms. Recurrences can occur after 10 years, so long-term clinical and radiological follow-up is required. The study of the molecular mechanisms involved in the development of these lesions is necessary to identify new prognostic markers. In this study, we evaluate the possible role of nicotinamide N-methyltransferase (NNMT) in ameloblastomas (AM) and odontogenic keratocysts (OKC). MATERIALS AND METHODS: A total of 105 surgical specimens of primary and recurrent lesions were obtained from 55 patients (25 AM, 30 OKC). In particular, 50 AMs (25 primary, 25 recurrences) and 55 OKCs (30 primary, 25 recurrences) were retrieved. We carried out immunohistochemical analyses to evaluate the cytoplasmic expression of NNMT, measuring the percentage of positive cells and the value of NNMT expression intensity. RESULTS: NNMT expression was significantly higher in recurrent than primary AMs (P = .0430). This result was confirmed by staining intensity, showing more cases with moderate/intense staining in recurrent AMs (P = .0470). NNMT expression was significantly lower in recurrent than primary OKC (P = .0014). Staining intensity showed more cases with moderate/intense staining in primary OKCs (P = .0276). CONCLUSIONS: This report is the first to evaluate NNMT expression in odontogenic lesions and to demonstrate a differential expression in recurrent AMs and OKCs, suggesting that there is potential for use of NNMT as prognostic marker.

Upregulation of Neural Cell Adhesion Molecule 1 (NCAM1) by hsa-miR-141-3p Suppresses Ameloblastoma Cell Migration.

BACKGROUND Neural cell adhesion molecule 1 (NCAM1; CD56) and E-cadherin are both involved in cell-cell adhesion and cell development processes, and their dysregulation is associated with various tumors. We hypothesized that dysregulated NCAM1 could suppress the invasive behavior of ameloblastoma (AB), and its expression was regulated by miR-141-3p. MATERIAL AND METHODS Real-time qPCR was performed to examine differences in miR-141-3p expression between AB tissues and normal oral tissues (NOMs). The potential target NCAM1 of miR-141-3p was predicted by bioinformatics analysis, which was validated through dual-luciferase assay. The mRNA and protein levels of NCAM1 were detected by real-time qPCR and Western blot, respectively. Furthermore, the expression and distribution of NCAM1 in AB were investigated through immunohistochemical staining, and immunohistochemical staining of E-cadherin was also performed. After overexpression of NCAM1, the migration of AM-1 cells was examined using wound-healing assay. RESULTS Real-time qPCR results confirmed that miR-141-3p was significantly downregulated in AB tissues. According to bioinformatics analysis, NCAM1 was a target of miR-141-3p, which was confirmed by dual luciferase assay. We found that NCAM1 was significantly upregulated in AB tissues at the mRNA and protein levels. Furthermore, NCAM1 and E-cadherin were mainly expressed on the cell membrane of AB. Downregulation of E-cadherin was found in AB tissues. As shown in wound-healing assay results, NCAM1 overexpression significantly inhibited the invasiveness of AM-1 cells. CONCLUSIONS In this study, highly expressed NCAM1 was found in AB, and it suppressed the migration of AB cells and was regulated by miR-141-3p, suggesting its potential value as a therapeutic target for AB.

Characterization of a novel CDC73 gene mutation in a hyperparathyrodism-jaw tumor patient affected by parathyroid carcinoma in the absence of somatic loss of heterozygosity.

Hyperparathyrodism-jaw tumor (HPT-JT) syndrome is an autosomal dominant disorder. Loss of function of the cell division cycle protein 73 homolog (CDC73) gene is responsible for the syndrome. This gene encodes an ubiquitously expressed 531 amino acid protein, parafibromin, that acts as a tumor suppressor. Loss of heterozygosity (LOH) of the CDC73 locus in many HPT-JT associated parathyroid tumors from patients with germline mutation is in accordance with Knudson's "two-hit" model for hereditary cancer. A 41-year-old man with mandible ossifying fibroma suffered from severe hypercalcemia due to parathyroid carcinoma (PC). Genetic analysis was performed to evaluate germinal and somatic CDC73 gene mutation as well as real-time qRT-PCR to quantify CDC73 mRNA, miR-155 and miR-664 expression levels. Immunohistochemistry and Western blotting (WB) assay were carried out to evaluate parafibromin protein expression. A novel heterozygous nonsense mutation, c.191-192 delT, was identified in the CDC73 gene. No CDC73 LOH was found in PC tissue, nor any differences in expression levels for CDC73 gene, miR-155 and miR-664 between PC and parathyroid adenoma control tissues. On the contrary, both immunohistochemistry and WB assay showed an approximate 90% reduction of parafibromin protein expression in PC. In conclusion, this study describes a novel germinal mutation, c.191-192 delT, in the CDC73 gene. Despite normal CDC73 gene expression, we found a significant decrease in parafibromin. We hypothesize that a gene silencing mechanism, possibly induced by microRNA, could play a role in determining somatic post-transcriptional inactivation of the wild type CDC73 allele.

Immunohistochemical evaluation of Sonic Hedgehog signaling pathway proteins (Shh, Ptch1, Ptch2, Smo, Gli1, Gli2, and Gli3) in sporadic and syndromic odontogenic keratocysts.

AIMS: The aim of this study was to compare the clinical and demographic features of 62 patients presenting sporadic odontogenic keratocysts (OKCs) or OKCs associated with nevoid basal cell carcinoma syndrome (NBCCS). In conjunction with this, we also evaluated the immunohistochemical expression of Shh, Ptch1, Ptch2, Smo, Gli1, Gli2 and Gli3 proteins in 86 OKCs. By doing this, we add to the understanding of the biology of this type of lesion, providing tools that will help facilitate the early diagnosis of NBCCS in those patients where the first manifestation is that of OKCs. METHODS: This is a retrospective study; patients were classified into two groups: group 1 which consisted of those who were not affected by NBCCS (49 patients and 57 OKCs) and group 2 which consisted of those who were diagnosed with NBCCS (13 patients and 29 OKCs). The clinical and demographic features were studied and the immunohistochemical expression of Sonic Hedgehog proteins (Shh, Ptch1, Ptch2, Smo, Gli1, Gli2, and Gli3) was analyzed in all samples. RESULTS: There was an increase in the expression of three proteins in the syndromic OKC, when compared to that of sporadic cysts. Shh and Gli1 showed higher cytoplasmic expression, while Smo revealed stronger nuclear and cytoplasmic expressions. CONCLUSION AND CLINICAL RELEVANCE: Our findings suggest that the expression patterns of important Shh pathway proteins can represent valuable markers for early diagnosis of NBCCS-associated OKCs, as the major criterion for the diagnosis of NBCCS is currently based on the late appearance of basal cellular carcinomas. Thus, standardizing a new diagnostic tool for diagnosis of NBCCS could be of great importance in the identification of therapeutic targets. We therefore suggest, as based on our findings, that OKCs showing high expression of Shh, Smo, and Gli1 are potentially associated with NBCCS.

Oct-4 and CD44 in epithelial stem cells like of benign odontogenic lesions.

Benign epithelial odontogenic lesions are great clinical importance entities that develop in the jaws from the tissues that form teeth. It has been shown that benign and malignant tumors are present in a large number of tumor stem cells, which has great implications in the development of these lesions. Oct-4 and CD44 have been demonstrated as important markers for tumoral stem cells. The aim of this study was investigate the presence of stem cell markers Oct-4 and CD44 in benign epithelial odontogenic lesions. Twenty odontogenic keratocysts (OKC), 20 ameloblastomas (AMB) of the solid/multicystic type and 20 adenomatoid odontogenic tumors (AOT) were retrospectively analyzed for immunohistochemical detection of Oct-4 and CD44 in their epithelial component. All cases were positive for the two markers, with the majority exhibiting a high expression. Analysis of the expression of Oct-4 revealed no statistically significant differences (p = 0.406) between the lesions studied. Regarding CD44, there was a significant difference between the cases of AMB and AOT in relation with OKC, with the latter presenting a greater labelling (p = 0.034). No statistically significant correlation between Oct-4 and CD44 was observed in the lesions. In our findings, the presence of stem cell-like phenotype at various sites of the epithelial component of the odontogenic lesions was identified, suggesting its possible participation in histogenesis and differentiation without, however, exerting influence on the aggressiveness of the lesions.

Prognostic importance of FGF2 and FGFR1 expression for patients affected by ameloblastoma.

BACKGROUND: Fibroblast growth factor 2 (FGF2) and FGF receptor 1 (FGFR1) have been investigated in different human neoplasms and were shown to play important roles in the pathogenesis of these diseases; however, very few are known regarding their prognostic importance in the context of ameloblastoma. Therefore, the aim of this study was to investigate whether the expression of FGF2 and FGFR1 is associated with ameloblastoma clinical behavior. METHODS: Fifty-eight cases of ameloblastoma arranged in tissue microarray were submitted to immunohistochemistry against FGF2 and FGFR1. Clinicopathological parameters regarding sex, age, tumor size, duration and location, treatment, recurrences, radiographic features, cortical disruptions, and follow-up data were obtained from patients' medical records and correlated with the molecules expression. Univariate and multivariate Cox regression analyses were used to investigate the prognostic potential of the biomarkers. RESULTS: Forty-four cases (75.9%) exhibited cytoplasmic positivity for FGF2 in central and peripheral epithelial cells, 46 of 58 (79.3%) showed FGFR1 cytoplasmic positivity predominantly in the columnar peripheral cells, and 43 cases (74.1%) were positive for both. Expression of FGF2 and FGF2 + FGFR1 was associated with tumor recurrences (P = .05). However, univariate and multivariate analyses did not demonstrate a significant influence of FGF2, FGFR1, or FGF2 + FGFR1 in the 5-year disease-free survival (DFS) rate (P = .27, P = .33, and P = .25, respectively). CONCLUSION: Cytoplasmic expression of FGF2 and FGF2 + FGFR1 is associated with ameloblastoma recurrence, but FGF2 and FGFR1 are not determinants of a lower DFS.

Expression of proteoglycans in two types of ameloblastoma: novel Immunohistochemical findings.

Alterations in cellular and extracellular matrix components play an important role during tumorigenesis; proteoglycans are included among these components. Ameloblastomas are odontogenic tumors distinguished as invasive and infiltrative neoplasms and are divided into different histological types, the most common of which are the unicystic ameloblastoma and the conventional ameloblastoma. The aim of this study was to identify the presence of two proteoglycans, perlecan and biglycan, in different types of ameloblastoma. Using immunohistochemistry, we determined the presence of both proteins in 28 unicystic ameloblastomas and 23 conventional ameloblastomas. We identified the cytoplasmic and nuclear presence of perlecan and the cytoplasmic presence of biglycan in both types of ameloblastoma. The mean values of immunoexpression were higher in the conventional type compared to the unicystic type. Neither the presence of biglycan in ameloblastomas nor the nuclear presence of perlecan in any odontogenic tumor has previously been reported. The differential immunoexpression of perlecan and biglycan in these types of ameloblastomas suggests their participation in the developmental process of these tumors.

Expression of ameloblastin in the human tooth germ and ameloblastoma.

OBJECTIVE: To analyse the immunohistochemical expression of ameloblastin in the bell stage of tooth germ and compare with ameloblastoma to determine the level of differentiation of tumour cells. STUDY DESIGN: This study included eleven human tooth germs with four in the early and seven in the late bell stage, and six selected archival tissue samples of ameloblastomas were studied using haematoxylin and eosin, Masson's trichrome and ameloblastin. RESULTS: All eleven tooth germs reacted positively to ameloblastin with a characteristic inverted and sequential pattern of expression in the acellular zone of the dental papilla and enamel organ. Of the six cases of ameloblastoma, five cases showed a variable level of expression of ameloblastin in the tumour cells, whereas in one case, ameloblastin was negative in the tumour cells but positive in the stromal fibrous tissue collar. CONCLUSION: Expression of ameloblastin in human tooth germ is related to differentiation and mineralization, and it correlates with the state of differentiation of the tumour cells in ameloblastoma.

Peripheral Ameloblastoma: A Study of 18 Cases and Usage of Ber-EP4 Immunohistochemistry to Rule out a Diagnosis of Intraoral Basal Cell Carcinoma.

PURPOSE: Peripheral ameloblastoma (PA) is a rare odontogenic tumor arising in the mucosa of tooth-bearing areas of the jaws that typically shows no radiographic evidence of bone involvement. It bears close histologic resemblance to intraoral basal cell carcinoma (IOBCC), an extremely rare entity. In our experience from previous published data, 3 cases of IOBCC were initially misdiagnosed as PA and were later differentiated from PA on the basis of Ber-EP4 protein expression. This unusual but significant experience set the premise for us to rule out a diagnosis of IOBCC by evaluating Ber-EP4 expression in all previously diagnosed cases of PA from the University of Florida Oral Pathology (UFOP) biopsy service archives. MATERIALS AND METHODS: With institutional review board approval, 18 cases of PA were retrieved from the UFOP biopsy service archives. We describe the clinicopathologic features of these cases and discuss the Ber-EP4 immunohistochemical staining performed to rule out a potential diagnosis of IOBCC. In addition, we conducted calretinin and epithelial membrane antigen staining for 1 case of PA. RESULTS: Most PAs presented in the lingual gingiva of the posterior mandible. Men were affected twice as often as women, and the average age at the diagnosis was 59 ± 21.5 years. Of the 18 lesions, 13 showed no reactivity to Ber-EP4, 4 displayed patchy membranous immunoreactivity, and 1 demonstrated nonspecific reactivity. CONCLUSIONS: We have concluded that all cases of PA that present with histologic overlap with basal cell carcinoma, especially those from incisional biopsies, those that appear significantly infiltrative, and those that appear ulcerated and/or demonstrate recurrence should be evaluated with Ber-EP4 to rule out IOBCC.

Expression of hMLH1 and hMSH2 proteins in ameloblastomas and tooth germs.

BACKGROUND: Mismatch repair proteins (MMRPs) are a group of nuclear enzymes that participate in the repair of base mismatches that occur during DNA replication in all proliferating cells. The most studied MMRPs are hMSH2 and hMLH1, which are known to be highly expressed in normal tissues. A loss of MMRPs leads to the accumulation of DNA replication errors in proliferating cells. Ki-67 is a biomarker regarded to be the gold-standard tool for determining cell proliferation by immunohistochemical methods. The aim of this study was to investigate the immunohistochemical expression of hMLH1, hMSH2 and Ki-67 proteins in ameloblastomas and tooth germs, to contribute to the understanding of the development of this odontogenic neoplasm. MATERIAL AND METHODS: Immunohistochemical assays to determine the presence of proteins hMSH2, hMLH1 and Ki-67 were performed in 80 ameloblastomas (40 solid and 40 unicystic) and five tooth germs. RESULTS: Unicystic ameloblastomas showed higher MMRP expression (hMLH1: 62.5 ± 43.4; hMSH2: 83.3 ± 47.8) than did solid ameloblastomas (hMLH1: 59.4 ± 13.5; hMSH2: 75.8 ± 40.2). Additionally, the cell proliferation index assessed by Ki-67 was inversely proportional to the expression of MMRP. Comparison between tooth germs and ameloblastoma revealed significantly higher expression of hMLH1, hMSH2 and Ki-67 in tooth germs (p=0.02). CONCLUSIONS: The differences of MMRP and Ki-67 immunoexpression between ameloblastomas and tooth germ suggest that alterations in the MMRP mechanisms could participate in the biological behavior of ameloblastomas.

Apoptosis and cell cycle aberrations in epithelial odontogenic lesions: An evidence by the expression of p53, Bcl-2 and Bax.

BACKGROUND: Ameloblastoma (AMB), odontogenic keratocyst (OKC) and adenomatoid odontogenic tumor (AOT) are epithelial odontogenic lesions with diverse biologic profiles. Defects in regulation of apoptosis and cell cycle may be involved in the development and progression of those lesions, therefore we aimed to investigate the expression of Bcl-2, Bax and p53 to better understand the possible role of these proteins in AMBs, OKCs and AOTs. MATERIAL AND METHODS: The studied sample consisted of 20 AMBs, 20 OKCs and 20 AOTs. Immunohistochemistry technique was performed for the antibodies p53, Bcl-2 and Bax. Immunoreactivity was observed in the epithelial component and positive cells were counted in five fields (100x magnification). Statistical analysis was performed with Kruskal-Wallis and Spearman tests (p <0.05). RESULTS: All lesions exhibited staining for the three studied proteins. There was no statistically significant associations between the expression of proteins and the lesions, however we identified a positive correlation between the expression of p53 and Bcl-2 (r = 0.200) and a negative correlation between p53 and Bax expressions (r = -0.100). In addition, p53 and Bax were similarly expressed between AMBs and OKCs. Bcl-2 was similarly expressed in AMBs and AOTs. CONCLUSIONS: Apoptosis regulatory proteins, as well as cell cycle proteins, are differently expressed in epithelial odontogenic lesions and their expression is possibly related to the biological behavior of AMB, OKC and AOT.

Immunohistochemical expression of podoplanin (D2-40), lymphangiogenesis, and neoangiogenesis in tooth germ, ameloblastomas, and ameloblastic carcinomas.

BACKGROUND: Ameloblastoma is a benign but locally aggressive odontogenic tumor, while ameloblastic carcinoma is its malignant counterpart. Angiogenesis and lymphangiogenesis in malignancies have been correlated with higher aggressiveness and poor prognosis, as well as greater expression of podoplanin by tumoral cells. METHODS: Immunohistochemical expression of podoplanin, CD34, and CD105 (endoglin) was evaluated in 53 ameloblastomas and three ameloblastic carcinomas; additionally, immunohistochemistry for podoplanin was also performed in 10 tooth germs. Microvessel density of blood and lymphatic vessels was calculated and compared between ameloblastomas and ameloblastic carcinomas. Immunoexpression of podoplanin by ameloblastic cells was evaluated in tooth germs, ameloblastomas, and ameloblastic carcinomas. RESULTS: Podoplanin was similarly expressed by odontogenic epithelial cells of tooth germs and ameloblastomas, while its expression was lower in ameloblastic carcinomas. There was no difference in microvessel density assessed by CD34 between ameloblastomas and ameloblastic carcinomas; nevertheless, the latter presented higher amounts of lymphatic and new formed blood vessels. CONCLUSIONS: Results suggest that podoplanin does not seem to be involved in invasion mechanisms of ameloblastic carcinomas, as its expression was decreased in the malignant tumoral cells. On the other hand, the increased lymphatic microvessel density and neoangiogenesis found in ameloblastic carcinomas could be related to its aggressiveness and potential for metastasis.

Expression of podoplanin and TGF-beta in glandular odontogenic cyst and its comparison with developmental and inflammatory odontogenic cystic lesions.

BACKGROUND: The number of studies investigating the immunohistochemical characteristics of glandular odontogenic cysts (GOCs) is limited, due to its rarity. TGF-beta has been suggested to induce podoplanin expression in some lesions. We aimed to evaluate and compare podoplanin and TGF-beta expression in GOC and other odontogenic cystic lesions. METHODS: A total of 43 samples including five GOCs, 10 dentigerous cysts (DCs), eight unicystic ameloblastoma (UAs), and 20 radicular cysts (RCs) were selected and subjected to immunohistochemical staining using monoclonal antibodies against podoplanin and TGF-beta. Kruskal-Wallis test and Mann-Whitney U-test were used for statistical analysis along with Bonferroni for adjusting P-values (P < 0.05). RESULTS: Podoplanin immunoreactivity was observed in 80%, 70%, and 100% of DCs, RCs, and UAs, respectively, while none of the GOCs were positive for this marker (P = 0.004). Significant differences were only found in the GOC specimens. TGF-beta positivity occurred in the capsule and epithelium of all GOCs and DCs, while RCs and UAs demonstrated different expression percentages in the capsular and epithelial tissues. Epithelial TGF-beta showed significant differences among the studied lesions (P = 0.007) with the main difference found between DCs with RCs and DCs with UAs. CONCLUSIONS: Lack of podoplanin expression might be involved in the characteristic histologic and behavioral features of GOC, which seems to be unrelated to TGF-beta expression.

Parenchyma-stromal interactions induce fibrosis by secreting CCN2 and promote osteoclastogenesis by stimulating RANKL and CD68 through activated TGF-ß/BMP4 in ameloblastoma.

BACKGROUND: Tumor parenchyma-stromal interactions affect the properties of tumors and their dynamics. Our group previously showed that secreted frizzled related protein (sFRP)-2 impairs bone formation and promotes bone invasion in ameloblastoma. However, the effects of the secreted growth factors CCN2, TGF-ß, and BMP4 on stromal tissues in ameloblastoma remain unclear. MATERIALS AND RESULTS: Thirty-five paraffin-embedded ameloblastoma cases, ameloblastoma-derived cell lines (AM-1), and primary cultures of ameloblastoma stromal fibroblasts (ASF) were used. Immunohistochemistry, MTT assay, Western blotting, and RT-PCR were performed on these samples. Parenchyma-stromal CCN2 overexpression correlated significantly with fibrous-type stroma, but not with myxoid-type stroma, suggesting a role of CCN2 in fibrosis (P < 0.05). Recombinant CCN2 induction of enhanced ASF proliferation in AM-1 medium supports this view. Conversely, BMP4 and TGF-ß were expressed in myxoid-type fibroblasts, but little expression was found in parenchyma. RANKL-positive and CD68-positive stromal cell populations were significantly greater in myxoid-type tumor areas than in fibrous-type tumor areas, while a higher Ki-67 labeling index was recorded in ameloblastoma with fibrous-type stroma. These data suggest that stromal properties influence bone resorption-related activities and growth rates, respectively. CONCLUSIONS: These results suggest that the effects of secreted growth factors are governed by ameloblastoma parenchyma-stromal interactions. CCN2 promotes fibrogenesis independent of TGF-ß signaling. Absence of CCN2 expression is associated with a phenotypic switch to a myxoid-type microenvironment that is conducive for TGF-ß/BMP4 signaling to promote osteoclastogenesis.

Immunoprofile of the adenomatoid odontogenic tumor.

This study was focused on the immunohistochemical profile of the adenomatoid odontogenic tumor. A Pub/Medline search revealed a number of immunohistochemical studies including cytokeratin profiles, extracellular matrix proteins, Integrins, ameloblast-associated proteins resorption regulators (RANK, RANKL), p53, PCNA, MDM2 protein, cyclin D1, Ki-67, Bcl-2 metallothionein, metalloproteinases, D56 hepatocyte growth factor, c-met, DNA methyltransferase, podoplanin, TGF-ßI, Smad-2/3, Smad-I-5/-8, Smad 4, beta- catenin, calretinin, and clonality. Careful interpretation of the findings indicates that the adenomatoid odontogenic tumor may be more of a hamartomatous than neoplastic nature.

TNF-α-induced IL-6 and MMP-9 expression in immortalized ameloblastoma cell line established by hTERT.

OBJECTIVE: Ameloblastoma (AM) shows locally invasive behaviour. However, biological investigations regarding regulation of gene expression associated with AM pathological features are difficult to perform, because AM cells can be passaged for a few generations due to senescence. We report a newly established immortalized AM cell line, AMB cells, by transfection with human telomerase reverse transcriptase (hTERT). Furthermore, we examined whether TNF-α modulates bone resorption-related genes, IL-6 and MMP-9 in cooperation with TGF-ß or IFN-γ. MATERIALS AND METHODS: Following transfection of an hTERT expression vector into AM cells using a non-viral method, the effects of cytokines on the expressions of IL-6 and MMP-9 mRNA were examined using real-time PCR. TNF-α-induced NF-κB activity was examined by western blotting and transcription factor assays. RESULTS: AMB cells continued to grow for more than 100 population doublings. Stimulation with TNF-α increased IL-6 and MMP-9 mRNA expressions, as well as NF-κB activation. Furthermore, TGF-ß and IFN-γ dramatically increased TNF-α-mediated expressions of MMP-9 and IL-6 mRNA, respectively, while those responses were suppressed by NF-κB inhibitor. CONCLUSION: We established an immortalized AM cell line by hTERT transfection. TNF-α-mediated regulation of MMP-9 and IL-6 via NF-κB may play an important role in the pathological behaviour of AMs, such as bone resorption.

Glucose Transporter 1 Expression in Odontogenic Keratocyst, Dentigerous Cyst, and Ameloblastoma: An Immunohistochemical Study.

INTRODUCTION: An array of odontogenic lesions manifest in the maxillofacial region with variable presentations. The biological behavior of lesions, such as odontogenic keratocyst (OKC), dentigerous cyst (DC), and ameloblastoma (AM) always invite debate. Glucose transporter 1 (GLUT-1) is proven to be an indicator of metabolic behavior of several benign and malignant neoplasms. AIM: The purpose of this study was to evaluate the expression of GLUT-1 in OKC, DC, and AM to understand their metabolic behavior. MATERIALS AND METHODS: Immunohistochemical expression of GLUT-1 was evaluated in each of the 15 cases of OKC, DC, and AM. The number of labeled cells, staining intensity, and membrane or cytoplasmic expressions were the parameters assessed and analyzed using chi-square test. RESULTS: All cases showed positive GLUT-1 expression: 86.6% OKC showed more than 50% labeled cells followed by DC (40%) and AM (26.5%); 53.3% OKC showed strong intensity in comparison to AM, which showed weak intensity in 53.3% cases; 86.6% of OKCs showed both membrane and cytoplasmic expression followed by DC (40%) and AM (26.6%), whereas 73.3% of AM showed only membrane expression followed by DC (60%) and OKC (13.3%). CONCLUSION: Odontogenic keratocyst was found out to be more metabolically active followed by DC and AM.

Immunohistochemical expression of GLUT-1, GLUT-3, and carbonic anhydrase IX in benign odontogenic lesions.

BACKGROUND: Some benign odontogenic lesions have a distinct biological behavior with high recurrence rates and local aggressive behavior. To determine whether glucose transporters proteins (GLUT-1 and GLUT-3) and carbonic anhydrase IX (CA IX) are associated with the development of as dentigerous cyst (DC), odontogenic keratocyst (OK), and ameloblastoma (AM), we evaluated the immunohistochemical expression of these proteins in these lesions. MATERIALS AND METHODS: Immunoexpression of GLUT-1, GLUT-3, and CA IX was evaluated semiquantitative fields in each of the 20 cases of OK, AM, and DC. The cases were classified according to the scores: 0 (0% positive cells), 1 (<10% of positive cells), 2 (10-50% of positive cells), and 3 (>50% of positive cells). The statistical analysis was performed using Pearson's chi-square, Kruskal-Wallis and Mann-Whitney tests. RESULTS: All cases were positive for GLUT-1 and 65% of OK showed scored 3. Staining was diffuse in 90% of OK and 85% of DC cases (P < 0.001). In 50% of OK and AM, staining was only observed in the membrane (P = 0.01). Most of the samples (66.7%) were negative for GLUT-3. Staining intensity for anhydrase was higher in the epithelium of DC when compared to OK (P = 0.01). Strong staining was observed in 55% of DC and 20% of OK samples (P = 0.01). CONCLUSIONS: These results suggest that GLUT-1 may be involved in the metabolic regulation of glucose in odontogenic lesions studied. In addition, CA IX appears to influence the development of AM, OK, and DC which can explain the differences their biological behavior.

Invadopodia proteins, cortactin, N-WASP and WIP differentially promote local invasiveness in ameloblastoma.

BACKGROUND: Cell migration and invasion through interstitial tissues are dependent upon several specialized characteristics of the migratory cell notably generation of proteolytic membranous protrusions or invadopodia. Ameloblastoma is a benign odontogenic epithelial neoplasm with a locally infiltrative behaviour. Cortactin and MMT1-MMP are two invadopodia proteins implicated in its local invasiveness. Other invadopodia regulators, namely N-WASP, WIP and Src kinase remain unclarified. This study addresses their roles in ameloblastoma. MATERIALS AND METHOD: Eighty-seven paraffin-embedded ameloblastoma cases (20 unicystic, 47 solid/multicystic, 3 desmoplastic and 17 recurrent) were subjected to immunohistochemistry for expression of cortactin, N-WASP, WIP, Src kinase and F-actin, and findings correlated with clinicopathological parameters. RESULTS: Invadopodia proteins (except Src kinase) and F-actin were widely detected in ameloblastoma (cortactin: n = 73/87, 83.9%; N-WASP: n = 59/87; 67.8%; WIP: n = 77/87; 88.5%; and F-actin: n = 87/87, 100%). Protein localization was mainly cytoplasmic and/or membranous, and occasionally nuclear for F-actin. Cortactin, which functions as an actin-scaffolding protein, demonstrated significantly higher expression levels within ameloblastoma tumoral epithelium than in stroma (P < 0.05). N-WASP, which coordinates actin polymerization and invadopodia-mediated extracellular matrix degradation, was overexpressed in the solid/multicystic subtype (P < 0.05). WIP, an upstream regulator of N-WASP, and F-actin were significantly upregulated along the tumour invasive front compared to tumour centres (P < 0.05). Except for males with cortactin overexpression, other clinical parameters (age, ethnicity and anatomical site) showed no significant correlations. CONCLUSIONS: Present results suggest that local invasiveness of ameloblastoma is dependent upon the migratory potential of its tumour cells as defined by their distribution of cortactin, N-WASP and WIP in correlation with F-actin cytoskeletal dynamics.