In uveal melanoma Gα-protein GNA11 mutations convey a shorter disease-specific survival and are more strongly associated with loss of BAP1 and chromosomal alterations than Gα-protein GNAQ mutations

ABSTRACT: Mutations in the Gα-genes GNAQ and GNA11 are found in 85-90% of uveal melanomas (UMs). We analyzed the association between GNAQ and GNA11 mutations with disease-specific survival, gene expression profiles, and cytogenetic alterations in 219 UMs. Our analysis 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). GNA11 mutated UMs displayed a shorter, but not significant, median months survival of 26.97 [95% CI 25.02-37.08] versus GNAQ patients median months survival of 31.5 [95% CI 30.97-53.51]. The GNA11 mutation was also 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). We used tandem-affinity-purification and mass spectrometry to show that the two derived 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.

ORGANISM(S): Homo sapiens

PROVIDER: GSE197656 | GEO | 2023/02/27

REPOSITORIES: GEO