The metastatic uveal melanoma cell line OMM2.5 displays selective sensitivity to the synthetic cannabinoid HU-210

Abstract

Purpose : This research evaluates the relevance of cannabinoid receptors in uveal melanoma(UM) and the therapeutic potential of synthetic cannabinoids in UM cell lines and in ex vivo orthotopic patient-derived xenografts(OPDX).UM is the most common intraocular malignancy in adults.Up to 50% of patients develop liver metastases with overall survival ranging from 4-15 months

Methods : Cannabinoid receptor gene expression in 80 primary UM samples within The Cancer Genome Atlas was analysed for association with survival. Immunoblotting analysed CB₁ receptor expression.In vitro assays utilised Mel285 and OMM2.5 human UM cell lines derived from tumours of the eye and a liver metastasis,respectively;and normal human epidermal-derived melanocytes(HEM).Cell viability was examined by measuring metabolic activity.Colony formation assays assessed long-term cell proliferation.Multiplex ELISA quantified secreted levels of inflammatory factors.Proteomic profiling of OMM2.5 cells treated with 20 µM HU-210 was performed by mass spectrometry

Results : Kaplan-Meier curves demonstrate a significant correlation between high CB₁expression and lower disease-free survival or high CB₂expression and lower overall survival in UM patients.CB₁expression was confirmed in both UM cell lines.10 µM or 20 µM HU-210, a CB₁/CB₂agonist, was required to significantly reduce cell viability in HEM or in Mel285 cells, respectively.However,HU-210 shows a selective effect in OMM2.5 where concentrations ranging 100 fM to 20 µM significantly reduce cell viability.In contrast,150 µM of JWH-133(CB₂agonist) was required to significantly reduced viability by 80% in both UM cell lines.20 µM HU-210 significantly reduces long-term proliferation of Mel285 and OMM2.5 cells and significantly alters secretion of 17 out of 54 inflammatory factors analysed in OMM2.5 cells.Proteome profiling of OMM2.5 cells treated with 20 µM HU-210 identified 55,41 and 193 proteins significantly differentially expressed after 4,8or24 hours treatment, respectively

Conclusions : Significant correlations occur between high CB₁ or CB₂expression and survival in UM patients.The potent cannabinoid HU-210 reduces viability and clone proliferation of UM cell lines and significantly alters the secretion of inflammatory factors in OMM2.5.Future directions will evaluate the molecular mechanisms of HU-210 action in UM cells and its translational potential in pre-clinical models

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.