Expression of Wilms' tumor 1 (WT1) in ameloblastomas

A systematic review on the molecular pathways of Ameloblastic carcinoma when compared to Ameloblastoma

BACKGROUND

Ameloblastic carcinoma (AC), malignancy originating from the odontogenic epithelium, shows histological overlap with ameloblastoma (AM). In order to unravel mechanisms driving AC, it is imperative to understand the molecular distinction between these two entities. This systematic review aims to highlight molecular and immunohistochemical markers involved in the pathogenesis of AC and to distinguish it from its histological mimic, AM.

RESEARCH DESIGN AND METHODS

Literature search across three databases including PubMed, Web of Sciences, and Scopus was carried out from year 1999 to 2023 for original human case control studies involving AM, AC, and controls as study groups. Various biological markers studied in the literature were grouped based on principal molecular pathways. Joanna Briggs Institute (JBI), a critical appraisal tool for case control studies, was used to assess the risk of bias (RoB).

RESULTS

Out of the 277 studies identified during the initial search, 28 studies were found eligible. These studies reported expression of various immunohistochemical (IHC), genetic and epigenetic markers in AC, AM, and controls through immunohistochemistry and gene sequencing.

CONCLUSION

Stem cells, epigenetics, and growth factors define the pathways involved in pathogenesis of AC and may prove to be a potential therapeutic target in the future.

Title of the article: diagnostic markers for odontogenic tumors: an insight: a review

Odontogenic tumors are a group of tumors that originate from the tissues associated with tooth development and are classified into benign or malignant based on their behavior and characteristics. Tumor markers are substances that can be found in the blood, urine, or tissues of individuals with cancer. They are the substances produced either by tumor cells itself or by the body in response to tumor growth, can sometimes be used in the diagnosis, prognosis, and monitoring of various types of tumors. However, the use of tumor markers in odontogenic tumors is not as common as it is in other types of cancers, and their utility in this context is limited. Tumor markers are not the main tools for diagnosing cancer; instead, they serve as supplementary laboratory tests to aid in the diagnosis. Researchers continue to investigate potential biomarkers to improve our understanding of these tumors and their behavior. With this concept in mind, the objective of this study is to elucidate the key diagnostic markers essential for diagnosing odontogenic tumors.

Intercellular signaling between ameloblastoma and osteoblasts

Ameloblastoma is an odontogenic tumor located in the bone jaw with clinical characteristics of extensive bone resorption. It is a locally invasive tumor with a high recurrence rate despite adequate surgical removal. In bone disease, tumors and other cells including osteoblasts, osteoclasts, and osteocytes in the bone microenvironment contribute to the pathogenesis of tumor growth. However, the effect of osteoblasts on ameloblastoma cells is not well-understood, and there has been limited research on interactions between them.

This study investigated interactions between ameloblastoma cells and osteoblasts using a human ameloblastoma cell line (AM-3 ameloblastoma cells) and a murine pre-osteoblast cell line (MC3T3-E1 cells). We treated each cell type with the conditioned medium by the other cell type. We analyzed the effect on cytokine production by MC3T3-E1 cells and the production of MMPs by AM-3 cells. Treatment with AM-3-conditioned medium induced inflammatory cytokine production of IL-6, MCP-1, and RANTES from MC3T3-E1 cells. The use of an IL-1 receptor antagonist suppressed the production of these inflammatory cytokines by MC3T3-E1 cells stimulated with AM-3-conditioned medium. The MC3T3-E1-conditioned medium triggered the expression of MMP-2 from AM-3 cells. Furthermore, we have shown that the proliferation and migration activity of AM-3 cells were accelerated by MC3T3-E1 conditioned media.

In conclusion, these intercellular signalings between ameloblastoma cells and osteoblasts may play multiple roles in the pathogenesis of ameloblastoma.

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Ameloblastoma conditioned medium induced IL-6, MCP-1 and RANTES production from osteoblast cell in IL-1 dependent manner.

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Unidentified factors from osteoblast conditioned medium induced MMP-2 production and stimulate proliferation and cellular motility of ameloblastoma cells.

miR-29a-3p promotes migration and invasion in ameloblastoma via Wnt/β-catenin signaling by targeting catenin beta interacting protein 1

BACKGROUND

Ameloblastoma (AB) is a common epithelial odontogenic tumor. The Wnt/β-catenin pathway has been found to be related to AB invasion.

METHODS

The alteration expression of microRNAs (miRNAs) and messenger RNAs (mRNAs) was performed by miRNA and mRNA microarray analysis and validated by quantitative real-time polymerase chain reaction (RT-PCR). The effects of miR-29a-3p on migration and invasion in AB cells were evaluated by a transwell assay. Bioinformatic prediction was conducted using the miRSystem and validated by quantitative RT-PCR, western blot, and a luciferase reporter assay.

RESULTS

miR-29a-3p was overexpressed in AB tissues, which promoted the migration and invasion of AB cells in vitro. Catenin beta interacting protein 1 (CTNNBIP1), a negative regulator of the Wnt/β-catenin pathway, was predicted to be a target of miR-29a-3p. miR-29a-3p inhibited the expression of CTNNBIP1 and promoted the expression of the downstream molecules of the Wnt/β-catenin pathway.

CONCLUSIONS

miR-29a-3p promoted migration and invasion in AB via Wnt/β-catenin signaling by targeting CTNNBIP1.

Genetic factors in the pathogenesis of ameloblastoma, dentigerous cyst and odontogenic keratocyst

Ameloblastoma (AB), dentigerous cyst (DC) and Odontogenic keratocyst (OKC) are odontogenic lesions with propensity to malignant transformation or local invasion. The molecular mechanisms of development of these lesions are not fully understood. However, some researches have reported dysregulation of tumor suppressor genes or oncogenes in these lesions. Down-regulation of P53 gene has been reported in AB, DC and OKC. Moreover, several long non-coding RNAs such as ENST00000512916 and KIAA0125 have been dysregulated in AB tissues. Single nucleotide polymorphisms within a variety of genes have been associated with certain types of odontogenic lesions. In the current review, we summarize the current data about the expression pattern of genes in these lesions and the observed association between genetic polymorphisms and development of these lesions.

Establishment and use of a three-dimensional ameloblastoma culture model to study the effects of butyric acid on the transcription of growth factors and laminin β3

OBJECTIVE

This study aimed to establish a three-dimensional (3D) culture method for ameloblastoma cell lines and to use the model to investigate the effect of butyric acid (BA), a periodontopathic bacterial metabolite, on the malignant transformation of ameloblastoma.

DESIGN

Three ameloblastoma cell lines (HAM1, HAM2, and HAM3) established from the same tumor were used in this study. A 3D culture model was established in low absorption dishes and was incubated for 48 h. The effects of BA on the transcription of growth factors and LMβ3 were examined by real-time reverse transcription PCR. Various BA concentrations (0.02, 0.2, 2, and 20 mM) were used to stimulate the cell cultures for 6 and 12 h.

RESULTS

A 3D culture model was established. Gene expression levels of epithelial growth factor (EGF), transforming growth factor beta 1 (TGFβ1), and laminin β3 (LMβ3) were higher in 3D than in 2D cultures. Cell morphology in 3D cultures did not change, while the transcription levels of EGF, TGFβ1, and LMβ3 were upregulated by BA in all cell lines.

CONCLUSION

The 3D culture model is more responsive to BA than the 2D culture model, and there is a possibility that the malignancy and progression of ameloblastoma via laminin 332 (LM332) is mediated by BA.

Effects of butyric acid, a bacterial metabolite, on the migration of ameloblastoma mediated by laminin 332

Ameloblastoma is a benign tumor that develops in the jawbone. Occasionally, however, it may become malignant and metastasize to other tissues. Although it has been suggested that various cytokines and several adhesion factors may play a role in its malignant transformation, the details have not been elucidated. In this context, it has been reported that butyric acid produced by periodontopathic bacteria causes progression of malignant tumors occurring in the mouth via podoplanin. However, the influence of butyric acid on ameloblastoma has not been clarified. In the present study, therefore, the expression of various cytokines and adhesion factors in ameloblastoma upon stimulation with butyric acid or cytokines was investigated using real-time reverse-transcription polymerase chain reaction. Three cell lines (HAM1, HAM2 and HAM3) established from the same ameloblastoma were used in the experiments. It was found that the expression of mRNAs for epidermal growth factor (EGF) and transforming growth factor beta 1 (TGFβ1) was increased in HAM2 and HAM3, respectively, upon stimulation with butyric acid. In addition, stimulation with EGF and TGFβ1 led to an increase in the expression of laminin β-3 mRNA in the respective cell lines. These results suggest that butyric acid may be involved in ameloblastoma exacerbation through the expression of laminin 332 (LM332) via EGF and TGFβ1 produced by ameloblastoma itself.

Mutational Signatures in Mandibular Ameloblastoma Correlate with Smoking

Ameloblastoma is a rare tumor of odontogenic epithelium, the low incidence rate of which precludes statistical determination of its molecular characterizations. Despite recent genomic and transcriptomic profiling, the etiology of ameloblastomas remains poorly understood. Risk factors of ameloblastoma development are also largely unknown. Whole exome sequencing was performed on 11 mandibular ameloblastoma samples. We identified 2 convergent mutational signatures in ameloblastoma: 1) a signature found in multiple types of lung cancers with probable etiology of tobacco carcinogens (COSMIC signature 4) and 2) a signature present in gingivobuccal oral squamous cell carcinoma and correlated with tobacco-chewing habits (COSMIC signature 29). These mutational signatures highlight tobacco usage or related mutagens as one possible risk factor of ameloblastoma, since the association of BRAF mutations and smoking was demonstrated in multiple studies. In addition to BRAF hotspot mutations (V600E), we observed clear inter- and intratumor heterogeneities. Interestingly, prior to BRAF mutation, important genes regulating odontogenesis mutated (e.g., corepressor BCOR), possibly playing important roles in tumorigenesis. Furthermore, recurrent mutations in the CDC73 gene, the germline mutations of which predispose patients to the development of jaw tumors, were found in 2 patients, which may lead to recurrence if not targeted by therapeutic drugs. Our unbiased profiling of coding regions of ameloblastoma genomes provides insights to the possible etiology of mandibular ameloblastoma and highlights potential disease risk factors for screening and prevention, especially for Asian patients. Because of the limited sample size and incomplete habitual, dietary, and occupational data, a causal link between tobacco usage and ameloblastoma still requires further investigations.