Clinicopathological features of myofibromas and myofibromatosis affecting the oral and maxillofacial region: A systematic review.

BACKGROUND: Myofibromas are rare benign neoplasms composed of myoid cells and myofibroblasts. This study aimed to systematically review case reports and a series of myofibromas (MF) and myofibromatosis (MFT) occurring in the oral and maxillofacial regions in order to describe their main clinicopathological features. METHODS: This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Electronic searches were conducted in 2023 in four databases: MEDLINE/PubMed, Web of Science, Scopus, and EMBASE. A manual search and a search in the grey literature were also conducted. The lesions were classified as MF or MFT according to their original report. RESULTS: A total of 169 cases were included in this systematic review. Men were slightly more affected, with a painless nodule. When occurring in soft tissue, MF usually developed in the gingiva (mean age:29.23 ± 21.93 years) and when it was intra-osseous, it occurred more frequently in the posterior mandible (mean age:14.33 ± 15.62 years). MFT occurred mainly in the mandible and was predominantly described as well-circumscribed masses of spindle cells organized in fascicles with a prominent vascular activity in a hemangiopericytoma-like pattern. The lesions were mainly positive for smooth muscle actin and vimentin immunomarkers. Surgical excision was the treatment of choice in the majority of cases and recurrence was observed in only three cases. CONCLUSION: MF and MFT affect more men, with an indolent clinical course. Intra-osseous tumors and MFT seem to occur more frequently in younger individuals. These lesions seem to have a good prognosis and low recurrence.

Connexin 43 expression in tooth germ and benign odontogenic tumors.

OBJECTIVE: The aim of this study was to investigate and compare the immunohistochemical expression of connexin 43 (Cx43) in tooth germs (TGs), ameloblastic fibromas (AFs), ameloblastic fibro-odontomas (AFOs), and conventional ameloblastomas (AMs). STUDY DESIGN: Nine TGs, 12 AFs, 12 AFOs, and 27 AMs were evaluated for Cx43 expression by immunohistochemistry. RESULTS: Most of the TGs expressed Cx43 in the mesenchyme (77.6%) and in the late stages of odontogenesis. Cx43 was more highly expressed (P < .05) in the mesenchymal layer of all groups than in the epithelial layer except for the AFOs. When comparing the expression of Cx43 in the different layers of the analyzed groups, statistically significant differences were observed between AFO vs AM (*P = .0158) in the epithelial layer and between AF vs AFO (P** = .0046) in the mesenchymal layer. CONCLUSIONS: The results obtained in this study showed that Cx43 is a protein with important expression in the mesenchymal layer of the embryonic and odontogenic tissues studied. It could be speculated that Cx43 participates in mineralization events based on the relationship of the expression of this protein between the epithelial and mesenchymal layers of odontogenic tissues.

Targeted-Lymphoma Drug Delivery System Based on the Sgc8-c Aptamer.

Aptamers are emerging as a promising new class of functional nucleic acids because they can specifically bind to any target with high affinity and be easily modified chemically with different pharmacophoric subunits for therapy. The truncated aptamer, Sgc8-c, binds to tyrosine-protein kinase-like 7 receptor, a promising cancer therapeutic target, allowing the recognition of haemato-oncological malignancies, among others. We have previously developed aptamer-drug conjugates by chemical synthesis, hybridizing Sgc8-c and dasatinib, a drug proposed for lymphoma chemotherapy. One of the best-characterised Sgc8-c-dasatinib hybrids, namely Sgc8-c-carb-da, was capable of releasing dasatinib at an endosomal-pH. Herein, we probed the therapeutic potential of this aptamer-drug conjugate. Sgc8-c-carb-da specifically inhibited murine A20 B lymphocyte growth and produced cell death, mainly by late apoptosis and necrosis. In addition, Sgc8-c-carb-da generated an arrest in cell proliferation, with a cell cycle arrest in the Sub-G1-peak. The mitochondrial potential was altered accordingly to these pathways. Moreover, using an in vitro cell-targeting assay that mimics in vivo conditions, we showed that Sgc8-c-carb-da displayed higher (2.5-fold) cytotoxic effects than dasatinib. These findings provide proof-of-concept of the therapeutic value of Sgc8-c-carb-da for lymphoma, creating new opportunities for the chemical synthesis of targeted biotherapeutics.

Metastatic and non-metastatic melanoma imaging using Sgc8-c aptamer PTK7-recognizer.

Melanoma is one of the most aggressive and deadly skin cancers, and although histopathological criteria are used for its prognosis, biomarkers are necessary to identify the different evolution stages. The applications of molecular imaging include the in vivo diagnosis of cancer with probes that recognize the tumor-biomarkers specific expression allowing external image acquisitions and evaluation of the biological process in quali-quantitative ways. Aptamers are oligonucleotides that recognize targets with high affinity and specificity presenting advantages that make them interesting molecular imaging probes. Sgc8-c (DNA-aptamer) selectively recognizes PTK7-receptor overexpressed in various types of tumors. Herein, Sgc8-c was evaluated, for the first time, in a metastatic melanoma model as molecular imaging probe for in vivo diagnostic, as well as in a non-metastatic melanoma model. Firstly, two probes, radio- and fluorescent-probe, were in vitro evaluated verifying the high specific PTK7 recognition and its internalization in tumor cells by the endosomal route. Secondly, in vivo proof of concept was performed in animal tumor models. In addition, they have rapid clearance from blood exhibiting excellent target (tumor)/non-target organ ratios. Furthermore, optimal biodistribution was observed 24 h after probes injections accumulating almost exclusively in the tumor tissue. Sgc8-c is a potential tool for their specific use in the early detection of melanoma.

Perfil inmunohistoquímico del mixoma odontogénico, con énfasis en marcadores de agresividad tumoral y microdensidad vascular / Perfil imuno-histoquímico do mixoma odontogênico, com ênfase em marcadores de agressividade tumoral e microdensidade vascular / Immunohistochemical profile of odontogenic myxoma, with a focus on microvascular density and tumor aggressiveness markers

Con el fin de tener una mayor comprensión sobre el comportamiento biológico del mixoma odontogénico (MO), se realizó inmunohistoquímica en 31 muestras, utilizando marcadores relacionados con mecanismos de progresión tumoral (adhesión, angiogénesis, apoptosis, inflamación y proliferación celular). El epitelio odontogénico fue detectado en cuatro muestras mediante CK19 y CD138, este último, mostró expresión baja en matriz extracelular (MEC) y alta en las células tumorales. La microdensidad vascular (MDV) media fue de 7.51 y 5.35 vasos marcados con CD34 y VEGF-A respectivamente. Una alta expresión de Orosomucoide-1 y Mast Cell Tryptase se observó células tumorales y en MEC. El MO mostró negatividad para Calretinina. Este perfil inmunohistoquímico, la baja expresión para Ki-67, Bcl-2 y p53, y la relativamente baja MDV, sugieren que la actividad proliferativa, anti-apoptótica o angiogénica no representan los principales mecanismos de crecimiento del MO, los cuales podrían estar asociados a eventos como inmunomodulación y degradación de la MEC.

Immunohistochemistry tests were performed in 31 samples to elucidate the biological behavior of the odontogenic myxoma (OM), using markers related to mechanisms of tumor progression (adhesion, angiogenesis, apoptosis, inflammation and cell proliferation). Odontogenic epithelium was detected in four samples with CK19 and CD138; the latter had a low expression in the extracellular matrix (ECM) and a high expression in tumor cells. The mean microvascular density (MVD), assessed with CD34 and VEGF-A, was 7.51 and 5.35 blood vessels. A high expression of orosomucoid-1 and mast cell tryptase was observed in tumor cells and ECM, while calretinin was negative. The immunohistochemical profile mentioned above, as well as the low expression of Ki67, Bcl-2 and p53 and the relatively low MVD, suggest that the proliferative, antiapoptotic and angiogenic activities do not represent the main growing mechanisms of OM, which could be associated to other events, such as immunomodulation and ECM degradation.

Para melhor compreensão do comportamento biológico do mixoma odontogênico (MO), imuno-histoquímica foi realizada em 31 amostras, utilizando marcadores relacionados aos mecanismos de progressão tumoral (adesão, angiogênese, apoptose, inflamação e proliferação celular). Epitélio odontogênico foi detectado em quatro amostras por CK19 e CD138, o último mostrou baixa expressão na matriz extracelular (MEC) e alta em células tumorais. A microdensidade vascular (MDV) média foi de 7.51 e 5.35 vasos marcados com CD34 e VEGF-A, respectivamente. Uma alta expressão de Orosomucoide-1 e Mast Cell Tryptase foi observada nas células tumorais e na MEC. O MO mostrou negatividade para Calretinina. O perfil imuno-histoquímico mencionado acima, a baixa expressão de Ki-67, Bcl-2 e p53 e a relativamente baixa MDV, sugerem que a atividade proliferativa, anti-apoptótica ou angiogênica não representam os principais mecanismos de crescimento do MO, os quais poderiam estar associados com eventos como imunomodulação e degradação da MEC.

Sgc8-c Aptamer as a Potential Theranostic Agent for Hemato-Oncological Malignancies.

Background: Aptamers represent an emerging class of oligonucleotides that have the ability to bind ligands with high affinity. Sgc8-c aptamer recognizes PTK7, a member of the catalytically defective receptor protein tyrosine kinase family that is upregulated in various cancers, including hemato-oncological malignancies. Herein, an Sgc8-c-NOTA-radiolabeled probe was prepared for theranostic purpose. Materials and Methods: In this work, an Sgc8-c-radiolabeled probe against PTK7 was prepared, and biological evaluations-pharmacokinetic studies, biodistribution analysis, and in vivo molecular imaging-were performed. To obtain the radiolabeled probe, a modified 5'-amino-derivative of the Sgc8-c aptamer was bound to the metal chelator NOTA, and subsequently labeled with 67Ga with high yield and radiochemical purity. The precursor, Sgc8-c-NOTA, the radio probe Sgc8-c-NOTA-67Ga, and its nonradioactive complex, Sgc8-c-NOTA-69/71Ga, were purified by reverse-phase high-performance liquid chromatography and characterized by electrospray ionization mass spectrometry. The binding ability of Sgc8-c-NOTA-67Ga was studied in vitro against purified PTK7 receptor. In addition, the binding was also evidenced against the hemato-oncological A20 cell line, derived from B lymphocytes, and the corresponding A20-green fluorescent protein (GFP)-transfected cells. The proof of concept was performed on A20-GFP tumor-bearing mice, in which the biodistribution of the radiolabeled probe was evaluated through imaging, using X-ray, fluorescence, and γ modalities. The specific uptake of the probe was confirmed by blocking with the Sgc8-c aptamer in an in vivo competition assay. Results: The biodistribution results showed considerable uptake in tumor since 2 h, with highest at 48 h postinjection. However, the blood and muscle ID/g (injected dose per gram of tissue) activities were decreasing with time and tumor/no-target ratios increasing to 20 at 24 h postinjection. These results are consistent with the in vivo images. Conclusions: This study supports the utility of Sgc8-c-NOTA radiolabeled as a theranostic agent.

DNA sequencing reveals AMELX, ODAM and MMP20 variations in dental fluorosis.

OBJECTIVE: Dental fluorosis (DF) is a dental development disorder caused by chronic fluoride overconsumption. There are differences in the susceptibility to and severity of DF in studied populations. The objective of the present study was to determine if single-nucleotide variations (SNVs) in the genes Amelogenin (AMELX), Odontogenic Ameloblast Associated (ODAM) and Matrix Metalloproteinase 20 (MMP20) are associated with DF by evaluating the relationship between variations in these genes and the degree of DF severity. SUBJECTS AND METHODS: Schoolchildren from two regions of Durango State and Mexico City, Mexico, were studied. The DF phenotype was determined using the Thylstrup and Fejerskov (TF) index. DNA was obtained from the buccal mucosa of each participant, and the presence of the variations rs946252 in AMELX, rs1514392 in ODAM and rs1784418 in MMP20 was determined by bidirectional DNA sequencing. RESULTS: A total of 180 DNA samples from 30 schoolchildren from 2 areas of Durango State were sequenced and analyzed. Differences in the severity of DF were found between the study areas (p = 0.006). SNVs in theMMP20 gene were present in 76.9 % of the participants in the high fluoride concentration and lower DF severity area. CONCLUSION: AMELX and ODAM variations was not different between the two populations with respect to DF severity; however, the presence of rs1784418 differed between phenotypes with regard to susceptibility to DF. Therefore, MMP20 might be related to the various phenotypes of DF and may serve as a protective marker.

Estudio de la proliferación celular en gérmenes dentarios humanos / Cell proliferation study in human tooth germs

El objetivo de este estudio fue conocer la expresión de MCM4-5-6 en gérmenes dentarios humanos en estado de campana. Materiales y Métodos Se obtuvieron preparados histológicos de 4 maxilares fetales incluidos en parafina en el archivo de bloques de la cátedra de Histología de la Facultad de Odontología, UdelaR. Se procedió al corte de los mismos en secciones para técnica de rutina (HE) y de IHQ para MCM 4, 5 y 6. Resultados: Las diferentes regiones del órgano del esmalte mostraron 100 % de positividad en el estrato intermedio, una variación de 100 % a 0 % en el epitelio interno del órgano del esmalte, desde el sector cervical al sector incisal del mismo, y0% tanto en el retículo estrellado como en el epitelio externo del órgano del esmalte. Conclusiones: Los resultados obtenidos permitieron evidenciar y confirmar la acción proliferativa de las diferentes zonas del órgano del esmalte.

The aim of this study was to determine the expression of MCM4-5-6 in human tooth germs in the bell stage. Materials and methods: Histological samples were collected from four fetal maxillae placed in paraffin at the block archive of the Histology Department of the School of Dentistry, UdelaR. Sections were made for HE routine technique and for immunohistochemistry technique for MCM4-5-6. Results: Different regions of the enamel organ showed 100% positivity in the intermediate layer, a variation from 100% to 0% in the inner epithelium from the cervical loop to the incisal area, and 0% in the stellar reticulum as well as the outer epithelium. Conclusions: The results show and confirm the proliferative action of the different areas of the enamel organ.

Comparative Study of the Minichromosome Maintenance Proteins Complex (MCM 4/5/6) in Ameloblastoma and Unicystic Ameloblastoma.

INTRODUCTION: Solid/conventional ameloblastoma (AM) and unicystic ameloblastoma (UAM) are the most frequent benign epithelial odontogenic tumors located in the maxillary region, and their treatment usually consists of extensive surgical resection. Therefore, it is relevant to study molecular markers to better understand the biological behavior of these tumors. The aim of this study was to describe and compare the expression of proteins related to cellular proliferation: Ki-67 and MCM4-6 complex. MATERIALS AND METHODS: An immunohistochemistry technique was performed, with antibodies against Ki-67, MCM4, MCM5, and MCM6, in 10 AM and 10 UAM tumors. The results were quantified using label index and analyzed statistically. RESULTS: AM and UAM had greater expression of MCM6, followed by MCM5, MCM4, and Ki-67 ( P < .05). Immunoexpression of Ki-67 and MCM5 was exclusively nuclear, whereas the expression of MCM4 and MCM6 was nuclear and cytoplasmic. CONCLUSION: The results suggest that MCM5 is a trustable cell proliferation marker with higher sensitivity compared with Ki-67 and may be useful to predict the biological behavior of AM and UAM. Despite this, further studies are necessary, including a correlation with clinical parameters to confirm these findings.

Derivatizations of Sgc8-c aptamer to prepare metallic radiopharmaceuticals as imaging diagnostic agents: Syntheses, isolations, and physicochemical characterizations.

Aptamers, oligonucleotides with the capability to bind to a target through non-covalent bonds with high affinity and specificity, have a great number of advantages as scaffold to prepare molecular imaging agents. In this sense, we have performed post-SELEX modifications of a truncated aptamer, Sgc8-c, which bind to protein tyrosine kinase 7 to obtain a specific molecular targeting probe for in vivo diagnosis and in vivo therapy. Herein, we describe the synthetic efforts to prepare conjugates between Sgc8-c and different metallic ions chelator moieties in short times, high purities, and adequate yields. The selected chelator moieties, derived from 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, 2-benzyl-1,4,7-triazacyclononane-1,4,7-triacetic acid, and 6-hydrazinonicotinic acid, were covalently attached at the 5'-aptamer position yielding the expected products which were stable in aqueous solution up to 75°C and in typical aptamer storage conditions at least for 30 days.

S100-A9 protein in exosomes from chronic lymphocytic leukemia cells promotes NF-κB activity during disease progression.

Chronic lymphocytic leukemia (CLL) is an incurable disease characterized by accumulation of clonal B lymphocytes, resulting from a complex balance between cell proliferation and apoptotic death. Continuous crosstalk between cancer cells and local/distant host environment is required for effective tumor growth. Among the main actors of this dynamic interplay between tumoral cells and their microenvironment are the nano-sized vesicles called exosomes. Emerging evidence indicates that secretion, composition, and functional capacity of exosomes are altered as tumors progress to an aggressive phenotype. In CLL, no data exist exploring the specific changes in the proteomic profile of plasma-derived exosomes from patients during disease evolution. We hereby report for the first time different proteomic profiles of plasma exosomes, both between indolent and progressive CLLs as well as within the individual patients at the onset of disease and during its progression. Next, we focus on the changes of the exosome protein cargoes, which are found exclusively in patients with progressive CLL after disease progression. The alterations in the proteomic cargoes underline different networks specific for leukemia progression related to inflammation, oxidative stress, and NF-κB and phosphatidylinositol 3-kinase/AKT pathway activation. Finally, our results suggest a preponderant role for the protein S100-A9 as an activator of the NFκB pathway during CLL progression and suggest that the leukemic clone can generate an autoactivation loop through S100-A9 expression, NF-κB activation, and exosome secretion. Collectively, our data propose a new pathway for NF-κB activation in CLL and highlight the importance of exosomes as extracellular mediators promoting tumor progression in CLL.