A Review of MicroRNA in Uveal Melanoma

Exploring of miR-155-5p, miR-181b-5p, and miR-454-3p Expressions in Circulating Cell-Free RNA: Insights from Peripheral Blood of Uveal Malignant Melanoma Patients

The identification of novel non-invasive biomarkers is imperative for the early diagnosis and monitoring of malignant melanoma. The objective of this study is to examine the expression levels of miR-155-5p, miR-181b-5p, and miR-454-3p in circulating cell-free RNA obtained from plasma samples of the 72 uveal malignant melanoma patients and to compare these levels with those of 72 healthy controls. The analysis showed that the expression level of the miR-181b-5p has increased 9.25 fold, and expression level of miR-155-5p has increased 6.67 fold, and miR-454-3p expression level has increased 4.14 fold in the patient group compared with the levels in the healthy control group (p = 0.005). It was found that the high expression levels of the three miRNAs were statistically significant in patients compared with in the healthy control group. The statistical evaluations between miRNA expression levels and clinical data showed that miR-155-5p had significant association with radiation therapy (p = 0.040), and miR-454-3p showed a significant association with smoking and alcohol use respectively (p = 0.009, and p = 0.026). The significantly elevated expression levels of miR-181b-5p, miR-155-5p, and miR-454-3p in the circulating cell-free RNA of plasma from uveal melanoma patients, in comparison to those in the healthy control group, suggest the potential usefulness of these biomarkers for both early diagnosis and disease monitoring. However, more extensive and future studies are needed to use these molecules in early diagnosis and disease monitoring.

The Role of Autophagy in Human Uveal Melanoma and the Development of Potential Disease Biomarkers and Novel Therapeutic Paradigms

Autophagy is a form of programmed cell degradation that enables the maintenance of homeostasis in response to extracellular stress stimuli. Autophagy is primarily activated by starvation and mediates the degradation, removal, or recycling of cell cytoplasm, organelles, and intracellular components in eukaryotic cells. Autophagy is also involved in the pathogenesis of human diseases, including several cancers. Human uveal melanoma (UM) is the primary intraocular malignancy in adults and has an extremely poor prognosis; at present there are no effective therapies. Several studies have suggested that autophagy is important in UM. By understanding the mechanisms of activation of autophagy in UM it may be possible to develop biomarkers to provide more definitive disease prognoses and to identify potential drug targets for the development of new therapeutic strategies. This article reviews the current information regarding autophagy in UM that could facilitate biomarker and drug development.

Signaling pathways driving ocular malignancies and their targeting by bioactive phytochemicals

Ocular cancers represent a rare pathology. The American Cancer Society estimates that 3,360 cases of ocular cancer occur annually in the United States. The major types of cancers of the eye include ocular melanoma (also known as uveal melanoma), ocular lymphoma, retinoblastoma, and squamous cell carcinoma. While uveal melanoma is one of the primary intraocular cancers with the highest occurrence in adults, retinoblastoma remains the most common primary intraocular cancer in children, and squamous cell carcinoma presents as the most common conjunctival cancer. The pathophysiology of these diseases involves specific cell signaling pathways. Oncogene mutations, tumor suppressor mutations, chromosome deletions/translocations and altered proteins are all described as causal events in developing ocular cancer. Without proper identification and treatment of these cancers, vision loss, cancer spread, and even death can occur. The current treatments for these cancers involve enucleation, radiation, excision, laser treatment, cryotherapy, immunotherapy, and chemotherapy. These treatments present a significant burden to the patient that includes a possible loss of vision and a myriad of side effects. Therefore, alternatives to traditional therapy are urgently needed. Intercepting the signaling pathways for these cancers with the use of naturally occurring phytochemicals could be a way to relieve both cancer burden and perhaps even prevent cancer occurrence. This research aims to present a comprehensive review of the signaling pathways involved in various ocular cancers, discuss current therapeutic options, and examine the potential of bioactive phytocompounds in the prevention and targeted treatment of ocular neoplasms. The current limitations, challenges, pitfalls, and future research directions are also discussed.

Genetic Basis and Molecular Mechanisms of Uveal Melanoma Metastasis: A Focus on Prognosis

Uveal melanoma (UM) is the most frequently found primary intraocular tumor, although it accounts for only 5% of all melanomas. Despite novel systemic therapies, patient survival has remained poor. Indeed, almost half of UM patients develop metastases from micro-metastases which were undetectable at diagnosis. Genetic analysis is crucial for metastatic risk prediction, as well as for patient management and follow-up. Several prognostic parameters have been explored, including tumor location, basal dimension and thickness, histopathologic cell type, vascular mimicry patterns, and infiltrating lymphocytes. Herein, the Authors review the available literature concerning cytogenetic prognostic markers and biochemical pathways correlated to UM metastasis development.

Circular RNA ZNF609 drives tumor progression by regulating the miR-138-5p/SIRT7 axis in melanoma

Melanoma serves as a prevailing and lethal skin malignancy with high mortality and a growing number of patients globally. Circular RNAs (circRNAs), as a type of emerging cellular regulator, are involved in the modulation of melanoma. Nevertheless, the function of circZNF609 in melanoma development remains obscure. In this study, we were interested in the effect and the underlying mechanism of circZNF609 on DNA damage during melanoma progression. The circZNF609 depletion significantly suppressed melanoma cell invasion, migration, and proliferation, and stimulated apoptosis. Meanwhile, comet assays showed that the tail length and γH2AX levels were elevated by circZNF609 depletion. Mechanically, circZNF609 sponged miR-138-5p and miR-138-5p targeted SIRT7 in the melanoma cells. The SIRT7 overexpression and miR-138-5p inhibitor could reverse circZNF609 depletion-mediated DNA damage and malignant progression in melanoma cells. Functionally, CircZNF609 promoted cell growth of melanoma in the nude mice. Consequently, we conclude that circZNF609 suppresses DNA damage and potentially enhances melanoma progression at the experimental condition by modulating the miR-138-5p/SIRT7 axis. Our finding provides new insights into the mechanism by which circZNF609 modulates the development of melanoma. CircZNF609 and miR-138-5p may be utilized as therapeutic targets for melanoma.

Bergamottin Induces DNA Damage and Inhibits Malignant Progression in Melanoma by Modulating miR-145/Cyclin D1 Axis

Background

Melanoma is a prevalent skin cancer with the high rate of metastasis and mortality, affecting the increasing number of people worldwide. Bergamottin (BGM) is a natural furanocoumarin derived from grapefruits and presents the potential anti-cancer activity in several tumor models. However, the role of BGM in the development of melanoma remains unclear. Here, we aimed to explore the effect of BGM on the DNA damage and progression of melanoma.

Methods

The effect of BGM on the melanoma progression was analyzed by CCK-8 assays, colony formation assays, transwell assays, Annexin V-FITC Apoptosis Detection Kit, cell-cycle analysis, in vivo tumorigenicity analysis. The mechanism investigation was performed using luciferase reporter gene assays, qPCR assays, and Western blot analysis.

Results

We identified that BGM repressed cell proliferation, migration, and invasion of melanoma cells. BGM induced cell cycle arrest at the G0/G1 phase and enhanced apoptosis of melanoma cells. The DNA damage in the melanoma cells was stimulated by the BGM treatment. Meanwhile, BGM was able to up-regulate the expression of miR-145 and miR-145 targeted Cyclin D1 in the melanoma cells. Furthermore, BGM inhibited the progression of melanoma by targeting miR-145/Cyclin D1 axis in vitro. BGM attenuated the tumor growth of melanoma in vivo.

Conclusion

Thus, we conclude that BGM induces DNA damage and inhibits tumor progression in melanoma by modulating the miR-145/Cyclin D1 axis. Our finding provides new insights into the mechanism by which BGM modulates the development of melanoma. BGM may be applied as a potential anti-tumor candidate for the clinical treatment of melanoma.