Ameloblastoma modifies tumor microenvironment for enhancing invasiveness by altering collagen alignment

Trends in Research of Odontogenic Keratocyst and Ameloblastoma

Odontogenic keratocyst (OKC) and ameloblastoma (AM) are common jaw lesions with high bone-destructive potential and recurrence rates. Recent advancements in technology led to significant progress in understanding these conditions. Single-cell and spatial omics have improved insights into the tumor microenvironment and cellular heterogeneity in OKC and AM. Fibroblast subsets in OKC and tumor cell subsets in AM have been analyzed, revealing mechanisms behind their biological behaviors, including OKC's osteolytic features and AM's recurrence tendencies. Spatial transcriptomics studies of AM have identified engineered fibroblasts and osteoblasts contributing to matrix remodeling gene and oncogene expression at the invasion frontier, driving AM progression. Three-dimensional culture technologies such as organoid models have refined analysis of AM subtypes; uncovered the role of AM fibroblasts in promoting tumor cell proliferation and invasion; and identified signaling pathways such as FOSL1, BRD4, EZH2, and Wnt as potential therapeutic targets. Organoid models also served as preclinical platforms for testing potential therapies. Although preclinical models for AM exist, reliable in vitro and in vivo models for OKC remain scarce. Promising mimic models, including human embryonic stem cells-derived epithelial cells, human oral keratinocytes, human immortalized oral epithelial cells, and HaCaT keratinocytes, show promise, but the advancements in 3-dimensional culture technology are expected to lead to further breakthroughs in this area. Artificial intelligence, including machine learning and deep learning, has enhanced radiomics-based diagnostic accuracy, distinguishing OKC and AM beyond clinician capability. Pathomics-based models further predict OKC prognosis and differentiate AM from ameloblastic carcinoma. Clinical studies have shown positive outcomes with targeted therapies. In a study investigating SMO-targeted treatments for nevoid basal cell carcinoma syndrome, nearly all OKC lesions resolved in 3 patients. A recent clinical trial with neoadjuvant BRAF-targeted therapy for AM demonstrated promising radiologic responses, potentially enabling organ preservation. This review highlights recent advancements and trends in OKC and AM research, aiming to inspire further exploration and progress in these fields.

Global Literature Analysis of Tumor Organoid and Tumor-on-Chip Research

Background: Tumor organoid and tumor-on-chip (ToC) platforms replicate aspects of the anatomical and physiological states of tumors. They, therefore, serve as models for investigating tumor microenvironments, metastasis, and immune interactions, especially for precision drug testing. To map the changing research diversity and focus in this field, we performed a quality-controlled text analysis of categorized academic publications and clinical studies. Methods: Previously, we collected metadata of academic publications on organoids or organ-on-chip platforms from PubMed, Web of Science, Scopus, EMBASE, and bioRxiv, published between January 2011 and June 2023. Here, we selected documents from this metadata corpus that were computationally determined as relevant to tumor research and analyzed them using an in-house text analysis algorithm. Additionally, we collected and analyzed metadata from ClinicalTrials.gov of clinical studies related to tumor organoids or ToC as of March 2023. Results and Discussion: From 3551 academic publications and 139 clinical trials, we identified 55 and 24 tumor classes modeled as tumor organoids and ToC models, respectively. The research was particularly active in neural and hepatic/pancreatic tumor organoids, as well as gastrointestinal, neural, and reproductive ToC models. Comparative analysis with cancer statistics showed that lung, lymphatic, and cervical tumors were under-represented in tumor organoid research. Our findings also illustrate varied research topics, including tumor physiology, therapeutic approaches, immune cell involvement, and analytical techniques. Mapping the research geographically highlighted the focus on colorectal cancer research in the Netherlands, though overall the specific research focus of countries did not reflect regional cancer prevalence. These insights not only map the current research landscape but also indicate potential new directions in tumor model research.

Differences in BRAF V600E mutation between the epithelium and mesenchyme in classic ameloblastoma

OBJECTIVE

Laser capture microdissection (LCM) was used to pinpoint the mutated tissue in ameloblastoma and investigate whether B-Raf proto-oncogene, serine/threonine kinase (BRAF) mutation is the main pathogenic gene in classic ameloblastoma.

STUDY DESIGN

A total of 24 patients with ameloblastoma scheduled to undergo surgery between 2000 and 2024 were included in the study. LCM was used to isolate tumor cells. Oxford nanopore technology (ONT) was used to analyze the collected cells. GO and KEGG enrichment analyses were then performed on the 300 most highly expressed genes in the epithelial tissue and mesenchyme.

RESULTS

Mandibular follicular ameloblastoma showed BRAF V600E mutations in all epithelial cells but not in the mesenchyme. The mutation rate was significantly higher in mandibular ameloblastomas compared to the maxilla (P < .05). RNA-seq showed that traditional follicular ameloblastoma epithelium was enriched in "growth factor receptor binding" and "angiogenesis regulation," while the mesenchyme was enriched in "ECM receptor interaction." KEGG enrichment analysis showed differential gene expression, mainly in MAPK and PI3K-AKT pathways.

CONCLUSION

Classical follicular ameloblastoma shows the presence of BRAF V600E mutation in epithelial tissue, with a higher mutation rate in the mandible than in the maxilla. The signaling pathways of MAPK and PI3K may be significantly involved in epithelial signal transduction.

Differentially expressed extracellular matrix genes functionally separate ameloblastoma from odontogenic keratocyst

BACKGROUND

Ameloblastoma and odontogenic keratocyst (OKC) are odontogenic tumors that develop from remnants of odontogenic epithelium. Both display locally invasive growth characteristics and high predilection for recurrence after surgical removal. Most ameloblastomas harbor BRAFV600E mutation while OKCs are associated with PATCH1 gene mutation but distinctive indicators of ameloblastoma growth characteristics relative to OKC are still unclear. The aim of this study was to assess hub genes that underlie ameloblastoma growth characteristics using bioinformatic analysis, ameloblastoma samples and mouse xenografts of human epithelial-derived ameloblastoma cells.

METHODS

RNA expression profiles were extracted from GSE186489 gene expression dataset acquired from Gene Expression Ominibus (GEO) database. Galaxy and iDEP online analysis tools were used to identify differentially expressed genes that were further characterized by gene ontology (GO) and pathway analysis using ShineyGO. The protein-protein interaction (PPI) network was constructed for significantly upregulated differentially expressed genes using online database STRING. The PPI network visualization was performed using Cytoscape and hub gene identification with cytoHubba. Top ten nodes were selected using maximum neighborhood component, degree and closeness algorithms and analysis of overlap was performed to confirm the hub genes. Epithelial-derived ameloblastoma cells from conventional ameloblastoma were transplanted into immunocompromised mice to recreate ameloblastoma in vivo based on the mouse xenograft model. The top 3 hub genes FN1, COL I and IGF-1 were validated by immunostaining and quantitative analysis of staining intensities to ameloblastoma, OKC samples and mouse ameloblastoma xenografts tissues.

RESULTS

Seven hub genes were identified among which FN1, COL1A1/COL1A2 and IGF-1 are associated with extracellular matrix organization, collagen binding, cell adhesion and cell surface interaction. These were further validated by positive immunoreactivity within the stroma of ameloblastoma samples but both ameloblastoma xenograft and OKC displayed only FN1 and IGF-1 immunoreactivity while COL 1 was unreactive. The expression levels of both FN1 and IGF-1 were much lower in OKC relative to ameloblastoma.

CONCLUSION

This study further validates a differentially upregulated expression of matrix proteins FN1, COL I and IGF-1 in ameloblastoma relative to OKC. It suggests that differential stromal architecture and growth characteristics of ameloblastoma relative to OKC could be an interplay of differentially upregulated genes in ameloblastoma.

Deposition of collagen III and alterations in basement membrane integrity as candidate prognostic markers in prostate cancer

The extracellular matrix surrounding the tumor undergoes changes in its organization during the metastasis process. The present study aims to quantify total collagen, collagen I (Col I) and collagen III (Col III), analyze the alignment of collagen fibers and assess the basement membrane integrity in samples from patients with metastatic and non-metastatic prostate cancer. Tissue samples from 60 patients were classified into groups based on prognostic parameters: better prognosis (n = 20), worse prognosis without metastasis (n = 23) and metastatic (n = 17). Picrosirius red with further analysis under polarizing microscope was used to quantify (with validation using immunohistochemistry) and analyze collagen alignment, and Periodic Acid Schiff staining was used to analyze the basement membrane integrity. The Col I/Col III ratio was found to be higher in the metastatic group than in the groups with better prognosis (p = 0.012) and worse prognosis without metastasis (p = 0.018). Basement membrane integrity constitution in malignant tumor tissue differed from that of adjacent non-tumor tissue (p < 0.001). Moreover, the worsening in the tumor tissue integrity was positively correlated with worse prognostic parameters. All in all, absence of Col III and basement membrane integrity might be indicators of poor prognosis in prostate cancer.