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Abstract Background Odontogenic myxoma (OM) is a benign, but locally invasive, neoplasm occurring in the jaws. However, the molecules implicated in its development are unknown. OM as well as Dental Follicle (DF), an odontogenic tissue surrounding the enamel organ, is derived from ectomesenchymal/mesencyhmal elements. To identify some protein that could participate in the development of this neoplasm, total proteins from OM were separated by two-dimensional electrophoresis and the profiles were compared with those obtained from DF, used as a control. Results We identified eight proteins with differential expression; two of them were downregulated and six upregulated in OM. A spot consistently overexpressed in odontogenic myxoma, with a molecular weight of 44-kDa and a pI of 3.5 was identified as the orosomucoid 1 protein. Western blot experiments confirmed the overexpression of this protein in odontogenic myxoma and immunohistochemical assays showed that this protein was mainly located in the cytoplasm of stellate and spindle-shaped cells of this neoplasm. Conclusion Orosomucoid 1, which belongs to a group of acute-phase proteins, may play a role in the modulation of the immune system and possibly it influences the development of OM.

Matrix metalloproteinases (MMPs) are involved in remodeling the extracellular matrix, but also participate in the development of physiopathologic processes. As they are overexpressed in different types of epithelial cancers, it has been suggested that their level expression could explain the different biological behavior between odontogenic cysts and tumors. Here, we compared the expression level and proteolytic activities of MMP-2 and MMP-9 in dental follicles, dentigerous cysts, odontogenic keratocysts and unicystic ameloblastomas. We found similar expression of MMP-2 in all tissues, but a higher activity in cystic and tumor lesions than follicles. On the other hand, MMP-9 expression and activity was greater in cysts and ameloblastoma than in follicles. However, no differences were found in expression or activity of both MMPs between cystic and tumor injuries, suggesting that they could participate in the growth of these lesions, but they cannot define their different biological behavior., Competing Interests: The authors declare that they have no conflict of interest., (© 2022 Craniofacial Research Foundation. Published by Elsevier B.V. All rights reserved.)

Objectives: Ameloblastoma is an odontogenic neoplasm of the mandible and maxilla with various histological types and subtypes. It has been reported that some ameloblastomas could arise from dentigerous cyst walls; thus, the development of ameloblastoma from dentigerous cysts may be due to differential protein expression. Our aim was to identify a membrane protein that is differentially expressed in ameloblastomas with respect to dentigerous cysts., Methods: We analyzed the SDS-PAGE profiles of membrane proteins from ameloblastomas and dentigerous cysts. The protein in a band present in the ameloblastoma sample, but apparently absent in the dentigerous cyst sample was identified via mass spectrometry as the chaperonin Hsp60. We used western blotting and immunohistochemistry to analyze its overexpression and localization in ameloblastoma., Results: We found a differential band of 95 kDa in the membrane proteins of ameloblastoma. In this band, the chaperonin Hsp60 was identified, and its overexpression was corroborated using western blotting and immunohistochemistry. Hsp60 was localized in the plasma membrane of all ameloblastoma samples studied; in addition, it was found in the cell nucleus of the plexiform subtype of conventional ameloblastoma., Conclusions: Our results suggest that Hsp60 may be involved in ameloblastoma development, and could therefore be a potential therapeutic target for ameloblastoma treatment., Competing Interests: Conflicts of interest All authors declare that there are no conflicts of interest., (Copyright © 2021 Japanese Association for Oral Biology. Published by Elsevier B.V. All rights reserved.)

Background: Dentigerous cyst (DC) occurs in approximately 20% of jaw cysts, being the second major common odontogenic cyst, after radicular cyst. This oral lesion has the ability to destroy maxillary bones and could be the origin of several odontogenic tumors. However, molecules implicated in its pathogenesis as well as those involved in its neoplastic transformation remain unknown. Here, we established a cell population derived from a DC as an in vitro model for the study of this oral lesion., Methods: Cell culture was performed from a DC from a 44-year-old male. Cells were cultured at 37°C in DMEM/F12 medium containing 10% fetal bovine serum. Expression of epithelial markers was analyzed by Western blot and immunofluorescence. Ultrastructural characterization was carried out by transmission electron microscopy. Conditioned media were obtained and characterized by zymography and Western blot., Results: Cells showed spindle-shaped morphology, but they express epithelial markers, such as cytokeratins and the odontogenic ameloblast-associated protein. The ultrastructural analysis showed well-formed desmosomes present in adhering contiguous cells, confirming the epithelial lineage of this cell population. Cells also contain several vesicles adjacent to plasma membrane, suggesting an active secretion. Indeed, the analysis of the conditioned medium revealed the presence of several secreted proteins, among them the matrix metalloproteinase-2., Conclusions: Our work provides a useful model to identify the molecular mechanisms involved in the pathogenesis of DC., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Ameloblastic carcinoma is a rare odontogenic tumour that combines the histological features of ameloblastoma with cytological atypia. Until 2005, the incidence of ameloblastic carcinoma was unknown, and since then, fewer than 60 cases have been reported. These tumours may originate from pre-existing tumours or cysts, or they arise de novo from the activation or transformation of embryological cells. PITX2 is a transcription factor that is a product and regulator of the WNT cell signalling pathway, which has been involved in development of several tumours. To analyse whether PITX2 could be involved in the biological behaviour of ameloblastic carcinoma, we analysed the expression of this transcription factor in a sample of this tumour and nine benign ameloblastomas to compare. The results of Western blotting and RT-PCR analyses were positive, and considering the hundreds of genes that PITX2 regulates, we believe that its expression could be intimately linked to the behaviour of ameloblastic carcinoma and possibly other odontogenic lesions., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Purpose: The comparative proteomic approach by a combination of 2-dimensional electrophoresis and matrix-assisted laser desorption-ionization-time of flight mass spectrometry (MS) analysis is an attractive strategy for the discovery of cancer biomarkers and therapeutic targets. The identification of protein biomarkers associated with ameloblastic carcinoma (AC), a malignant epithelial odontogenic tumor, will potentially improve the diagnostic and prognostic accuracy for this malignant neoplasm. The aim of the present study was to identify highly expressed proteins in AC that could be considered as potential biomarkers., Materials and Methods: The protein profile of an AC was compared with the protein profiles of 3 cases of benign ameloblastoma. Proteins that showed increased levels in AC were identified using MS, and the augmented amount of some of these proteins in the malignant lesion was confirmed by Western blot or immunohistochemistry., Results: We detected a total of 782 spots in the protein profile of AC, and 19 of them, showing elevated levels compared with benign ameloblastoma, were identified using MS. These proteins have been implicated in several cellular functions, such as cell structure, metabolism, stress response, and signal transduction., Conclusions: The increased expression of the identified proteins and the minor expression of some proteins that might inhibit tumor progression could be involved in the evolution from a benign lesion to carcinoma., (Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)