Crizotinib and Darovasertib Significantly Reduce Metastatic Uveal Melanoma Cell Proliferation, Alone and In Combination

Abstract Background 50% of uveal melanoma (UM) patients develop metastatic UM (mUM). A combination of crizotinib, a c-Met receptor tyrosine kinase inhibitor, and darovasertib, a protein kinase C inhibitor, is in clinical trials for mUM (NCT05987332). This combination has not been tested in mUM liver metastases-derived OMM2.5 cells. OMM2.5 cells may help further elucidate the drugs' mechanism of action. This study evaluated darovasertib and crizotinib in OMM2.5 cells using metabolic activity and live cell proliferation assays. Methods The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay assessed cell metabolic activity at 96 hours post treatment. The IncuCyte S3 Live-Cell Analysis System assessed cell proliferation from 12 to 96 hours post treatment. Drug combinations exerting additive or synergistic effects were identified by comparing predicted and observed drug effects and by Bliss independence analysis. Results 96-hour treatment with 10 or 20 µM crizotinib significantly reduced OMM2.5 metabolic activity on average to 2.2% (p=0.0081) or 1.1% (p=0.0069), respectively. 96-hour treatment with 0.63, 1.25, 10 or 20 µM darovasertib significantly reduced OMM2.5 metabolic activity on average to 43.3% (p=0.0402), 41.6% (p=0.0305), 34.8% (p=0.0284) or 24.8% (p=0.0013), respectively. Darovasertib and crizotinib in combination had no significant effect on cell metabolic activity. At 96 hours, 5, 10 or 20 µM crizotinib significantly reduced OMM2.5 proliferation on average to 19.4% (p<0.0001), 11.24% (p<0.0001), or 9.4% (p<0.0001) respectively. 0.63, 1.25, 2.5, 5, 10 and 20 µM darovasertib significantly reduced OMM2.5 proliferation on average to 74.7% (p=0.0291), 73% (p=0.0175), 66.9% (p=0.0076), 63% (p=0.0045), 47.5% (p=0.0005) or 40.5% (p=0.0002) respectively. 0.63 µM crizotinib and 2.5 µM darovasertib in combination had a synergistic effect on cell proliferation at 96 hours based on Bliss independence analysis. Conclusion 0.63 µM crizotinib and 2.5 µM darovasertib in combination, had a synergistic effect on OMM2.5 cell proliferation.