Background and aim of the study: Mutations in the G alpha-genes GNAQ and GNA11 are found in 85-90% of uveal melanomas (UM). Aim of the study is to understand whether the mutations in both genes... Show moreBackground and aim of the study: Mutations in the G alpha-genes GNAQ and GNA11 are found in 85-90% of uveal melanomas (UM). Aim of the study is to understand whether the mutations in both genes differentially affect tumor characteristics and outcome and if so, to identify potential mechanisms. Methods: We analyzed the association between GNAQ and GNA11 mutations with disease specific survival, gene expression profiles, and cytogenetic alterations in 219 UMs. We used tandem-affinity-purification, mass spectrometry and immunoprecipitation to identify protein interaction partners of the two G-proteins and analyzed their impact on DNA-methylation. Results: GNA11 mutation was associated with: i) an increased frequency of loss of BRCA1- associated protein 1 (BAP1) expression (p = 0.0005), ii) monosomy of chromosome 3 (p < 0.001), iii) amplification of chr8q (p = 0.038), iv) the combination of the latter two (p = 0.0002), and inversely with v) chr6p gain (p = 0.003). Our analysis also showed a shorter disease-specific survival of GNA11-mutated cases as compared to those carrying a GNAQ mutation (HR = 1.97 [95%CI 1.12-3.46], p = 0.02). GNAQ and GNA11 encoded G-proteins have different protein interaction partners. Specifically, the Tet Methylcytosine Dioxygenase 2 (TET2), a protein that is involved in DNA demethylation, physically interacts with the GNAQ protein but not with GNA11, as confirmed by immunoprecipitation analyses. High risk UM cases show a clearly different DNA-methylation pattern, suggesting that a different regulation of DNA methylation by the two G-proteins might convey a different risk of progression. Conclusions: GNA11 mutated uveal melanoma has worse prognosis and is associated with high risk cytogenetic, mutational and molecular tumor characteristics that might be determined at least in part by differential DNA-methylation. (C) 2022 Elsevier Ltd. All rights reserved. Show less
Amaro, A.; Croce, M.; Ferrini, S.; Barisione, G.; Gualco, M.; Perri, P.; ... ; Gangemi, R. 2020
Uveal melanoma (UM) is a rare tumor of the eye that leads to deadly metastases in about half of the patients. ADAM10 correlates with c-Met expression in UM and high levels of both molecules are... Show moreUveal melanoma (UM) is a rare tumor of the eye that leads to deadly metastases in about half of the patients. ADAM10 correlates with c-Met expression in UM and high levels of both molecules are related to the development of metastases. MiR122 and miR144 modulateADAM10andc-Metexpression in different settings. We hypothesized a potential onco-suppressive role for miR122 and miR144 through modulation of ADAM10 and c-Met in UM. We analyzed the UM Cancer Genome Atlas data portal (TCGA) dataset, two other cohorts of primary tumors and five human UM cell lines for miR122 and miR144 expression by miR microarray, RT-qPCR, Western blotting, miR transfection and luciferase reporter assay. Our results indicate that miR122 and miR144 are expressed at low levels in the UM cell lines and in the TCGA UM dataset and were down-modulated in a cohort of seven UM samples, compared to normal choroid. Both miR122 and miR144 directly targetedADAM10andc-Met. Overexpression of miR122 and miR144 led to reduced expression of ADAM10 and c-Met in the UM cell lines and impaired cell proliferation, migration, cell cycle and shedding of c-Met ecto-domain. Our results show that miR122 and miR144 display an onco-suppressive role in UM through ADAM10 and c-Met modulation. Show less
Piaggio, F.; Tozzo, V.; Bernardi, C.; Croce, M.; Puzone, R.; Viaggi, S.; ... ; Amaro, A. 2019
