Expressions of microRNA-29a and microRNA-34a in pleomorphic adenomas of salivary glands

MiR-34a promotes mitochondrial pathway of apoptosis in human salivary gland epithelial cells by activating NF-κB signaling

To investigate the potential molecular mechanism of miR-34a in Sjögren's syndrome (SS). Transmission electron microscopy was used to observe the salivary gland tissues of mild and severe SS patients. SS mouse model was constructed and injected with miR-34a antagonist. HSGE cells were transfected with miR-34a mimic. Starbase predicted miR-34a binding sites and validated them with dual-luciferase reporter assays. Immunohistochemistry, HE staining, CCK-8, TUNEL assay, flow cytometry, immunofluorescence and Western Blot were used to investigate the effects of miR-34a on NF-κB signaling and mitochondrial pathway of apoptosis in HSGE cells. Severe SS patients showed obvious mitochondrial damage and apoptosis in salivary glands. MiR-34a was overexpressed and NF-κB signaling is activated in salivary glands of severe SS patients. Inhibition of miR-34a alleviated salivary gland injury in SS mice, as well as inhibited the activation of NF-κB signaling and mitochondrial pathway of apoptosis. In conclusion, miR-34a promoted NF-κB signaling by targeting IκBα, thereby causing mitochondrial pathway apoptosis and aggravating SS-induced salivary gland damage.

MicroRNA copy number alterations in the malignant transformation of pleomorphic adenoma to carcinoma ex pleomorphic adenoma

OBJECTIVE

This study used array comparative genomic hybridization to assess copy number alterations (CNAs) involving miRNA genes in pleomorphic adenoma (PA), recurrent pleomorphic adenoma (RPA), residual PA, and carcinoma ex pleomorphic adenoma (CXPA).

MATERIALS AND METHODS

We analyzed 13 PA, 4 RPA, 29 CXPA, and 14 residual PA using Nexus Copy Number Discovery software. The miRNAs genes affected by CNAs were evaluated based on their expression patterns and subjected to pathway enrichment analysis.

RESULTS

Across the groups, we found 216 CNAs affecting 2261 miRNA genes, with 117 in PA, 59 in RPA, 846 in residual PA, and 2555 in CXPA. The chromosome 8 showed higher involvement in altered miRNAs in PAs and CXPA patients. Six miRNA genes were shared among all groups. Additionally, miR-21, miR-455-3p, miR-140, miR-320a, miR-383, miR-598, and miR-486 were prominent CNAs found and is implicated in carcinogenesis of several malignant tumors. These miRNAs regulate critical signaling pathways such as aerobic glycolysis, fatty acid biosynthesis, and cancer-related pathways.

CONCLUSION

This study was the first to explore CNAs in miRNA-encoding genes in the PA-CXPA sequence. The findings suggest the involvement of numerous miRNA genes in CXPA development and progression by regulating oncogenic signaling pathways.

The potential role of miRNAs in the pathogenesis of salivary gland cancer - A Focus on signaling pathways interplay

Salivary gland cancer (SGC) is immensely heterogeneous, both in terms of its physical manifestation and its aggressiveness. Developing a novel diagnostic and prognostic detection method based on the noninvasive profiling of microribonucleic acids (miRs) could be a goal for the clinical management of these specific malignancies, sparing the patients' valuable time. miRs are promising candidates as prognostic biomarkers and therapeutic targets or factors that can advance the therapy of SGC due to their ability to posttranscriptionally regulate the expression of various genes involved in cell proliferation, differentiation, cell cycle, apoptosis, invasion, and angiogenesis. Depending on their biological function, many miRs may contribute to the development of SGC. Therefore, this article serves as an accelerated study guide for SGC and the biogenesis of miRs. Here, we shall list the miRs whose function in SGC pathogenesis has recently been determined with an emphasis on their potential applications as therapeutic targets. We will also offer a synopsis of the current state of knowledge about oncogenic and tumor suppressor miRs in relation to SGC.

Salivary gland tumors exhibit distinct miRNA signatures involved in Wnt/β-Catenin signaling in formalin fixed paraffin embedded tissue samples

Advances in high-throughput genomic technologies have enabled the identification of numerous selective tumor markers. However, adapting these newly identified markers to clinical practice is not always possible because most RNA molecules, including mRNAs of protein-coding genes and long non-coding RNAs, are not stable under laboratory conditions, making their testing a major challenge. In contrast to long RNA molecules, miRNAs offer a great advantage in that they are relatively stable due to their small size. Accordingly, herein we aimed to determine the expression levels of miRNAs that are involved in Wnt/β-catenin signaling pathway in formalin fixed paraffin embedded (FFPE) tissue samples of patients with salivary gland tumors. A total of 42 patients with salivary gland tumors were included in the study. The miRNA expression signatures were evaluated using the RT-qPCR. As a result, β-catenin positivity was observed in all salivary gland tumors without distinguishing between benign and malignant phenotypes. Remarkably, we found that miR-200a and miR-373 were significantly upregulated whereas miR-30c were downregulated in tissues of patients with salivary gland tumors, compared to adjacent healthy tissue samples. In addition, distinct expression signatures of these miRNAs were significantly associated with the clinicopathological findings of patients such as perineural invasion and lymph node metastasis. Additionally, miR-145 and miR-30a were found to be specifically downregulated in a mucoepidermoid carcinoma. Also, miR-26b was selectively increased in pleomorphic adenomas of the salivary gland. Collectively, our findings suggest that these miRNAs may play chief roles in the differential diagnosis of salivary gland tumors.

AN INTEGRATED APPROACH TO THE MORPHOLOGICAL DIAGNOSIS OF DIFFERENT TYPES OF PLEOMORPHIC ADENOMAS OF THE SALIVARY GLAND: LONG-TERM RESEARCH RESULTS

OBJECTIVE

The aim: To describe an integrated approach to the morphological diagnosis of different types of pleomorphic adenomas of the salivary gland.

PATIENTS AND METHODS

Materials and methods: Surgical and biopsy material from 30 patients with pleomorphic adenomas of epithelial, mixed and mesenchymal variants was studied using histological, immunohistochemical, genetic, morphometric and statistical methods.

RESULTS

Results: The results of research allowed us to identify methods for determination the pleomorphic adenomas types. The first method requires an immunohistochemical reaction with a monoclonal antibody to human papillomavirus type 16, followed by counting the percentage of positively stained cells in the tumor. Thus, the mesenchymal variant of the tumor is diagnosed when the percentage of positively stained cells is < 40%. In the mixed variant, this indicator is ≥ 40%, but ≤ 70%, and in epithelial variant - > 70%. The second method was based on the multivariate discriminant analysis. Three formulae were derived to determine the tumor types (Fmesenchymal = - 41.03 + 4.96Х1 + 1.11Х2, Fepithelial = - 22.27 + 3.46Х1 + 0.85Х2, Fmixed = - 122.25 + 5.63Х1 + 3.2Х2, here Х1 - number of vessels, Х2 - specific volume of parenchyma).

CONCLUSION

Conclusions: The authors identified several methods for determining the histological variants of pleomorphic adenomas. These methods will improve the morphological diagnosis of pleomorphic adenomas variants in the preoperative and postoperative periods.