[Uveal Melanoma: Molecular and Genetic Mechanisms of Development and Therapeutic Approaches].

Uveal melanoma (UM) is a neuroectodermal tumor that results from malignant transformation of melanocytes in the eye uvea, including the iris, the ciliary body, and the choroid. UM accounts for 5% of all melanoma cases and is extremely aggressive with half of the UM patients developing metastases within the first 1-2 years after tumor development. Molecular mechanisms of UM carcinogenesis are poorly understood, but are known to differ from those of skin melanoma. Activating mutations of the GNAQ and GNA11 genes, which code for the large G protein subunits Gq and G11, respectively, are found in 90% of UM patients. The Gaq/PKC/MAPK signaling pathway is a main signaling cascade that leads to the transformation of melanocytes of the uveal tract, and major regulators of the cascade provide targets for the development of drugs. Metastatic UM (MUM) is most often associated with mutations of BAP1, EIF1AX, GNA11, GNAQ, and SF3B1. A combination of a commercial expression test panel of 15 genes and a mutation panel of 7 genes, supplemented with data on the size of the primary tumor, is highly efficient in predicting the risk of metastasis. The risk of metastasis determines the choice of therapy and the patient follow-up regimen. However, no systemic therapy for MUM has been developed to date. New drugs undergoing clinical trials are mostly targeted drugs designed to inhibit the protein products of mutant genes or immunotherapeutic agents designed to stimulate the immune response against specific antigens. In addition to these approaches, potential therapeutic targets of epigenetic regulation of UM development are considered in the review.

Ciliary body myxoid epithelioid sarcoma in a cat: a case report.

BACKGROUND: The majority of primary, intraocular tumors in cats originate from the uvea and include feline diffuse iris melanoma, lymphoma, and iridociliary epithelial adenoma or adenocarcinoma. In this case report, we describe for the first time the clinical, histological, and immunohistochemical findings of a rare myxoid intraocular neoplasm arising from the ciliary body in a cat. CASE PRESENTATION: A 14-year-old, female, spayed domestic shorthaired cat was presented for evaluation of discolouration of the right eye. Upon examination, a clear to light whitish-tan, bubble-shaped intraocular mass adherent to the inferior ciliary body and extending into the anterior chamber was noted. Within five weeks, the tumor was significantly larger and the eye had developed secondary glaucoma so was enucleated. Light microscopic examination of the globe revealed a multinodular, hypocellular neoplasm arising from the ciliary body composed of interwoven spindle cells embedded in abundant amounts of a lightly basophilic myxoid matrix. Neoplastic cells exhibited strong immunoreactivity for cytokeratin while also showing moderate to strong immunoreactivity to vimentin. A diagnosis was therefore made of an unusual intraocular myxoid epithelioid sarcoma arising from the ciliary body. CONCLUSIONS: Although apparently exceedingly rare, epithelioid myxosarcoma should be included as a differential diagnosis for intraocular tumors in cats and they represent a clinical, histologic, and immunohistochemical diagnostic challenge. Early surgical intervention should be considered to prevent local invasion and ascension to the brain.

Immunotherapy response and resistance in patients with advanced uveal melanoma: a retrospective cohort study.

Metastatic uveal melanoma (mUM) is associated with poor prognosis. Ipilimumab/nivolumab has shown antitumor efficacy in phase II studies. Tebentafusp resulted in longer overall survival (OS) compared to investigator`s choice in a phase III study. We sought to describe the radiological response patterns of mUM patients treated with immunotherapy. Patients with mUM treated with ipilimumab/nivolumab and tebentafusp between July 2018 and December 2022, with available radiological assessment per RECISTv1.1 and/or imPERCIST5, were retrospectively identified and included. Progression-free survival (PFS) and OS rates, liver-specific response and pathological assessment in available liver biopsies were evaluated. In the ipilimumab/nivolumab group, median PFS (mPFS) was 2.9 months (95% CI 2.2-28.6) and mOS 28.9 months (95% CI 12.7-NR). Complete (CMR) and partial (PMR) metabolic response per imPERCIST5, and partial response (PR) per RECISTv1.1 were associated with longer PFS and OS by trend, compared to morphologically and metabolically stable or progressive disease. In the tebentafusp group, mPFS was 2.7 months (95% CI 2.2-3) and mOS 18.6 months (95% CI 11.5-NR). PMR and PR were associated with longer PFS by trend. In both treatments, the overall treatment response was associated with the radiological response at the liver site. In available liver tumor biopsies, differences in pathological and radiological responses were noted. ImPERCIST5 and RECIST v1.1 are valuable tools in the radiological response assessment, but both methods display limitations. Accurate biomarkers to stratify patients at risk for disease progression and future translational studies to investigate mechanisms of response and resistance are required.

STAT6/LINC01637 axis regulates tumor growth via autophagy and pharmacological targeting STAT6 as a novel strategy for uveal melanoma.

Compelling evidence has revealed a novel function of the STAT pathway in the pathophysiology of uveal melanoma (UM); however, its regulatory mechanisms remain unclear. Here, we analyzed the clinical prognostic value of STAT family genes in UM patients using bioinformatics approaches and found that high STAT6 expression is associated with poor prognosis. Furthermore, cellular experiments and a nude mouse model demonstrated that STAT6 promotes UM progression through the autophagy pathway both in vivo and in vitro. Next, RIP-PCR revealed that STAT6 protein binds to LINC01637 mRNA, which in turn regulates STAT6 expression to promote UM growth. Finally, molecular docking indicated that STAT6 is a target of Zoledronic Acid, which can delay UM tumorigenicity by inhibiting STAT6 expression. Taken together, our results indicate that the STAT6/LINC01637 axis promotes UM progression via autophagy and may serve as a potential therapeutic target for UM.

TREM2, a critical activator of pyroptosis, mediates the anti­tumor effects of piceatannol in uveal melanoma cells via caspase 3/GSDME pathway

Uveal melanoma (UM) is the most prevalent type of primary intraocular malignancy and is prone to metastasize, particularly to the liver. However, due to the poor understanding of the pathogenesis of UM, effective therapeutic approaches are lacking. As a phenolic compound extracted from grapes, piceatannol (PIC) exhibits anti­cancer properties. To the best of our knowledge, however, the effects of PIC on UM have not been well investigated. Therefore, in the present study, considering the impact of pyroptosis on modulating cell viability, the mechanism underlying the effects of PIC on UM cell proliferation was explored. The inhibitory effect of PIC on proliferation of UM cells was detected by cell counting kit­8 assay. Wound healing was used to investigate the effects of PIC on the migration of UM cells. Activity detecting assays were performed to test the apoptosis and oxidant level in UM cells. Western blotting and RT­qPCR were used to detect the inflammatory and pyroptotic levels of UM cell after PIC treatment. PIC­treated UM cells were screened by high­throughput sequencing to detect the differential expression of RNA and differential genes. Si­TREM2 transfection was used to verify the important role of TREM2 in the effects of PIC. Immunohistochemical staining was used to observe the expressions of TREM2 and GSDMR of tumor in nude mice after PIC administration. PIC effectively inhibited proliferation ability of C918 and Mum­2b UM cell lines via enhancing apoptosis, as evidenced by enhanced activities of caspase 3 and caspase 9. In addition, treatment of UM cells with PIC attenuated cell migration in a dose­dependent manner. PIC increased reactive oxygen species levels and suppressed the activity of the antioxidant enzymes superoxide dismutase, glutathione­S­transferase, glutathione peroxidase and catalase. PIC inhibited inflammatory responses in C918 cells. PIC treatment upregulated IL­1ß, IL­18 and Nod­like receptor protein 3 and downregulated gasdermin D (GSDMD). RNA sequencing results revealed the activation of an unconventional pyroptosis­associated signaling pathway, namely caspase 3/GSDME signaling, following PIC treatment, which was mediated by triggering receptor expressed on myeloid cells 2 (TREM2) upregulation. As an agonist of TREM2, COG1410­mediated TREM2 upregulation inhibited proliferation of C918 cells, displaying similar effects to PIC. Furthermore, PIC inhibited tumor growth via regulating the TREM2/caspase 3/GSDME pathway in a mouse model. Collectively, the present study revealed a novel mechanism underlying the inhibitory effects of PIC on UM, providing a potential treatment approach for UM in clinic.

Pregnancy and survival-related outcomes of uveal melanoma treated with brachytherapy in women of reproductive age.

BACKGROUND: To examine if pregnancy affects the prognosis of uveal melanoma (UM) patients undergoing plaque brachytherapy (PBT) and to assess if PBT has any subsequent impact on pregnancy outcomes. METHODS: A retrospective, single-center study was carried out at Beijing Tongren Hospital, focusing on women of childbearing age diagnosed with UM and treated with iodine-125 plaque brachytherapy. Both the outcomes of pregnancies and the health status of the fetuses were monitored. Survival analyses were conducted using the Kaplan-Meier method, with endpoints being metastasis and death. RESULTS: A total of 13 patients who had full-term pregnancies and 96 non-pregnant women matched by age and tumor size were included. The mean follow-up time was 67.0 ± 27.7 months (median:66.0 months, range:21.0 to 116.0 months). In the pregnant group, two patients developed metastases, one of whom died shortly after delivery; local recurrence of UM occurred in 2 patients after or during delivery, and 2 other patients developed secondary glaucoma due to radiation retinopathy. None of the other pregnant patients reported any signs of disease progression. In the control group, 18 metastasis cases including 12 deaths were documented. Pregnant patients and matched control subjects showed no statistical difference in both Metastasis-free survival (hazard ratio (HR): 0.66, 95% confidence interval (CI): 0.15-2.86; P = 0.576) and overall survival (HR: 0.48, 95% CI: 0.06-3.66; P = 0.464). All pregnant patients carried the pregnancy to term and delivered healthy children with no report of placental or infant metastases to date. CONCLUSION: Pregnancy does not appear to negatively impact the prognosis of UM patients undergoing PBT. PBT showed no observable detriment to maternal fertility and exhibited no teratogenic effects on the fetus. However, the long-term implications of PBT on pregnancy remain uncertain, necessitating additional, prolonged follow-up studies.

Identifying biomarkers for treatment of uveal melanoma by T cell engager using a QSP model.

Uveal melanoma (UM), the primary intraocular tumor in adults, arises from eye melanocytes and poses a significant threat to vision and health. Despite its rarity, UM is concerning due to its high potential for liver metastasis, resulting in a median survival of about a year after detection. Unlike cutaneous melanoma, UM responds poorly to immune checkpoint inhibition (ICI) due to its low tumor mutational burden and PD-1/PD-L1 expression. Tebentafusp, a bispecific T cell engager (TCE) approved for metastatic UM, showed potential in clinical trials, but the objective response rate remains modest. To enhance TCE efficacy, we explored quantitative systems pharmacology (QSP) modeling in this study. By integrating a TCE module into an existing QSP model and using clinical data on UM and tebentafusp, we aimed to identify and rank potential predictive biomarkers for patient selection. We selected 30 important predictive biomarkers, including model parameters and cell concentrations in tumor and blood compartments. We investigated biomarkers using different methods, including comparison of median levels in responders and non-responders, and a cutoff-based biomarker testing algorithm. CD8+ T cell density in the tumor and blood, CD8+ T cell to regulatory T cell ratio in the tumor, and naïve CD4+ density in the blood are examples of key biomarkers identified. Quantification of predictive power suggested a limited predictive power for single pre-treatment biomarkers, which was improved by early on-treatment biomarkers and combination of predictive biomarkers. Ultimately, this QSP model could facilitate biomarker-guided patient selection, improving clinical trial efficiency and UM treatment outcomes.

Association of female sex with cataract surgery in the general population but not in plaque brachytherapy-treated uveal melanoma patients.

Cataract is a leading cause of blindness worldwide, necessitating a deeper understanding of its risk factors. We analyzed two cohorts: 1000 individuals from the general Swedish population and 933 patients who received plaque brachytherapy for uveal melanoma. Using Kaplan-Meier and cumulative incidence analyses, as well as Cox and competing risk regressions, we assessed whether there is a relationship between sex and cataract surgery. In the general population, female sex was a significant risk factor for cataract surgery, with a 10-year incidence of 16% compared to 10% for males (subdistribution hazard ratio adjusted for age, 1.35, P < 0.001). In the brachytherapy cohort, female sex was not associated with an increased incidence of cataract surgery, with a 10-year incidence of 25% versus 23% for males (HR 1.08, P = 0.61). Visual acuity at the time of cataract surgery did not significantly differ between sexes in either cohort, suggesting that differences in surgery rates are not due to health-seeking behavior or surgery assessment thresholds. These findings indicate that female sex is associated with a higher risk of cataract surgery in the general population, but not among those treated with plaque brachytherapy for uveal melanoma.

The role of signaling pathways mediated by the GPCRs CysLTR1/2 in melanocyte proliferation and senescence.

In contrast with sun exposure-induced melanoma, rarer melanocytic tumors and neoplasms with low mutational burden present opportunities to study isolated signaling mechanisms. These include uveal melanoma and blue nevi, which are often driven by mutations within the G protein-coupled signaling cascade downstream of cysteinyl leukotriene receptor 2. Here, we review how the same mutations within this pathway drive the growth of melanocytes in one tissue but can inhibit the growth of those in another, exemplifying the role of the tissue environment in the delicate balance between uncontrolled cell growth and senescence.

Construction of a prognostic risk model for uveal melanoma based on immune-related long noncoding RNA.

Uveal melanoma (UM) is a common health challenge worldwide as a prevalent intraocular malignancy because of its high mortality rate. However, clinical workers do not have an accurate prognostic tool now. Immune function is closely related to tumor development. Interestingly, researchers have identified that long noncoding RNAs (lncRNAs) are tightly associated with biological processes at the cellular level, particularly their involvements in immune response and its regulation of the growth of tumor cells. Hence, lncRNAs may be involved in the progression of uveal melanoma. UM patients' RNA expression matrices were extracted from TCGA database. The targeted immune genes were filtered by weighted correlation network analysis and the immune-related lncRNAs with a high prognostic relevance were obtained by Cox regression analysis and least absolute shrinkage and selection operator regression analysis. Each sample was scored according to those lncRNA expression and divided into high-risk and low-risk group. We confirmed the sensitivity and independence of our risk model compared to the tumor mutation burden score. Finally, we demonstrated the clinical relevance of our model by examining its sensitivity to different drugs. The risk score based on our risk model was significantly independent of other clinical parameters in either univariate (hazard ratio = 109.852 [15.738-766.749], P value < .001) or multivariate (hazard ratio = 114.075 [15.207-855.735], P value < .001) analyses. The ROC curves of this model imply high predictive accuracy for 1-year, 3-year, and 5-year survival (1-year area under the curve [AUC] = 0.849, 3-years AUC = 0.848, and 5-years AUC = 0.761). Our study revealed that immune-related lncRNAs are significant in the clinical diagnosis, treatment and prognosis of UM patients. We successfully constructed a lncRNA-based prognostic risk model which may serve as a future reference for the diagnosis and prognosis of UM. Based on this model we also validated the sensitivity of some cancer drugs, which has implications for the future immunotherapy and drug development.