Effects of Oncogenic Gαq and Gα11 Inhibition by FR900359 in Uveal Melanoma.

Uveal melanoma is the most common intraocular tumor in adults and often metastasizes to the liver, leaving patients with few options. Recurrent activating mutations in the G proteins, Gαq and Gα11, are observed in approximately 93% of all uveal melanomas. Although therapeutic intervention of downstream Gαq/11 targets has been unsuccessful in treating uveal melanoma, we have found that the Gαq/11 inhibitor, FR900359 (FR), effectively inhibits oncogenic Gαq/11 signaling in uveal melanoma cells expressing either mutant Gαq or Gα11. Inhibition of oncogenic Gαq/11 by FR results in cell-cycle arrest and induction of apoptosis. Furthermore, colony formation is prevented by FR treatment of uveal melanoma cells in 3D-cell culture, providing promise for future in vivo studies. This suggests direct inhibition of activating Gαq/11 mutants may be a potential means of treating uveal melanoma. IMPLICATIONS: Oncogenic Gαq/11 inhibition by FR900359 may be a potential treatment option for those with uveal melanoma. ©2018 American Association for Cancer Research.