Novel uveal melanoma patient-derived cell line and organoid models show increased treatment resistance compared with commercially available cell lines

The objective of this study was to compare drug response of uveal melanoma patient-derived cell lines (PDLs) and patient-derived organoids (PDOs) with response of commercially available cell lines and contextualize laboratory outputs in terms of clinical trial results. Uveal melanoma commercial cell lines, PDLs, and PDOs were treated with drugs that were ultimately utilized in clinical trials. Four treatments were chosen for promising laboratory results that failed to yield clinical response, while darovasertib was a surrogate positive control given initial favorable clinical trial data in the neoadjuvant setting. Drug concentrations were matched to laboratory work that supported progression to clinical trials. Viability was measured using PrestoBlueHS Cell Viability Reagent. Commercial cell lines showed promising viability reduction similar to prior laboratory results with treatments, including 5-μM darovasertib, 700-nM selumetinib, 700-nM selumetinib + 1000-nM MK-2206, 500-nM sotrastaurin + 1000-nM alpelisib, and 100-nM trametinib, with overall viability reduced to 32.5% for all drugs. However, PDLs (viability 52.8%) and PDOs (viability 80.4%) showed more treatment resistance (P < 0.05), better simulating ultimate lack of efficacy found in clinical trials. While uveal melanoma with BAP1 loss demonstrated greater treatment resistance under some conditions, other factors such as cell morphology or culture in a three-dimensional environment appeared to be more consistent drivers of therapeutic sensitivity. PDLs and PDOs may more accurately represent uveal melanoma clinical response. Demonstrating efficacy of novel therapeutics in these models could improve the likelihood of successful translation for future clinical trials, but future studies are needed to define clinically meaningful in-vitro response thresholds.