Author/Editor		Černe, Jasmina Živa; Hartig, Sean Michael; Hamilton, Mark Patrick; Chew, Sue Anne; Mitsiades, Nicholas; Poulaki, Vassiliki; McGuire, Sean E.
Title		Protein kinase C inhibitors sensitize GNAQ mutant uveal melanoma cells to ionizing radiation
Type		članek
Publication year		2014
ISSN		0146-0404 - Investigative ophthalmology & visual science
Language		eng
Abstract		Purpose: Uveal melanoma (UM) tumors require large doses of radiation therapy (RT) to achieve tumor ablation, which frequently results in damage to adjacent normal tissues leading to vision-threatening complications. Approximately 50% of UM patients present with activating somatic mutations in the gene encoding for G protein %q-subunit (GNAQ), which lead to constitutive activation of downstream pathways including protein kinase C (PKC). In this study, we investigated the impact of small molecule PKC inhibitors bisindolylmaleimide I (BIM) and sotrastaurin (AEB071) combined with ionizing radiation (IR) on survival in UM cell lines. Methods: Cellular radiosensitivity was determined using a combination of proliferation, viability, and clonogenic assays. Cell cycle effects were measured by flow cytometry. Transcriptomic and proteomic profiling were performed by quantitative real-time PCR, reverse phase protein array analysis, and immunofluorescence. Results: We found that the PKC inhibitors combined with IR significantly decreased the viability, proliferation, and clonogenic potential of GNAQmt, but not GNAQwt cells, compared to IR alone. Combined treatment increased the anti-proliferative and pro-apoptotic effects of IR in GNAQmt cells through delayed DNA damage resolution and enhanced induction of proteins involved in cell cycle arrest, cell growth arrest, and apoptosis. Conclusions: Our pre-clinical results suggest that combined modality treatment may allow for reductions in the total RT dose and/or fraction size, which may lead to better functional organ preservation in the treatment of primary GNAQmt UM. These findings suggest future clinical trials combining PKC inhibitors with RT in GNAQmt UM warrant consideration.
Keywords		melanoma GNAQ mutation protein kinase C melanom GNAQ mutacija protein kinaza C