High Cysteinyl Leukotriene Receptor 1 Expression Correlates with Poor Survival of Uveal Melanoma Patients and Cognate Antagonist Drugs Modulate the Growth, Cancer Secretome, and Metabolism of Uveal Melanoma Cells

Abstract

Metastatic uveal melanoma (UM) is a rare, but often lethal, form of ocular cancer arising from melanocytes within the uveal tract. UM has a high propensity to spread hematogenously to the liver, with up to 50% of patients developing liver metastases. Unfortunately, once liver metastasis occurs, patient prognosis is extremely poor with as few as 8% of patients surviving beyond two years. There are no standard-of-care therapies available for the treatment of metastatic UM, hence it is a clinical area of urgent unmet need. Here, the clinical relevance and therapeutic potential of cysteinyl leukotriene receptors (CysLT1 and CysLT2) in UM was evaluated. High expression of CYSLTR1 or CYSLTR2 transcripts is significantly associated with poor disease-free survival and poor overall survival in UM patients. Digital pathology analysis identified that high expression of CysLT1 in primary UM is associated with reduced disease-specific survival (p = 0.012; HR 2.76; 95% CI 1.21–6.3) and overall survival (p = 0.011; HR 1.46; 95% CI 0.67–3.17). High CysLT1 expression shows a statistically significant (p = 0.041) correlation with ciliary body involvement, a poor prognostic indicator in UM. Small molecule drugs targeting CysLT1 were vastly superior at exerting anti-cancer phenotypes in UM cell lines and zebrafish xenografts than drugs targeting CysLT2. Quininib, a selective CysLT1 antagonist, significantly inhibits survival (p < 0.0001), long-term proliferation (p < 0.0001), and oxidative phosphorylation (p < 0.001), but not glycolysis, in primary and metastatic UM cell lines. Quininib exerts opposing effects on the secretion of inflammatory markers in primary versus metastatic UM cell lines. Quininib significantly downregulated IL-2 and IL-6 in Mel285 cells (p < 0.05) but significantly upregulated IL-10, IL-1β, IL-2 (p < 0.0001), IL-13, IL-8 (p < 0.001), IL-12p70 and IL-6 (p < 0.05) in OMM2.5 cells. Finally, quininib significantly inhibits tumour growth in orthotopic zebrafish xenograft models of UM. These preclinical data suggest that antagonism of CysLT1, but not CysLT2, may be of therapeutic interest in the treatment of UM.

Cysteinyl Leukotriene Pathway and Cancer

“…Uveal melanoma cell lines derived from primary (Mel285, Mel270) and metastatic (OMM2.5) uveal melanoma expressed CysLT 1 R and CysLT 2 R [ 81 ]. Montelukast, quininib and 1,4-dihydroxy quininib significantly inhibited uveal melanoma cells in a time- and dose-dependent manner, whereas a CysLT 2 -selective antagonist, HAMI 3379, did not show growth inhibition effect [ 81 ]. Quininib significantly inhibited long-term proliferation, altered the cancer secretome of inflammatory and angiogenic factors and inhibited oxidative phosphorylation [ 81 ].…”

“…Montelukast, quininib and 1,4-dihydroxy quininib significantly inhibited uveal melanoma cells in a time- and dose-dependent manner, whereas a CysLT 2 -selective antagonist, HAMI 3379, did not show growth inhibition effect [ 81 ]. Quininib significantly inhibited long-term proliferation, altered the cancer secretome of inflammatory and angiogenic factors and inhibited oxidative phosphorylation [ 81 ].…”

“…A study assessing data of 80 primary uveal melanoma samples in The Cancer Genome Atlas (TCGA) showed that higher expression of CYSLTR1 and CYSLTR2 genes were significantly associated with poorer disease-free survival and overall survival [ 81 ]. However, the study group also examined the tissue from 52 patients of primary uveal melanoma using tissue microarray and only found poorer overall survival in those with higher CysLT 1 R expression, whereas CysLT 2 R expression was not associated with survival [ 81 ].…”

Inhibition of Metastatic Uveal Melanoma Cell Proliferation by the Histone Deacetylase 6 Inhibitor, Ricolinostat, is Linked to Altered Microphthalmia-associated Transcription Factor and Phospho-ERK Expression

“…Protein was isolated from Mel270, Mel285, OMM2.5 and ARPE19 cells at a cell density of 1 x 10 6 or 4 x 10 5 and immunoblotting was performed as described [36]. For validation of proteomics data, protein isolated for MS study was utilized.…”

“…Three commercially available HDAC6i (Tubastatin A, ACY-1215 and Tubacin) were selected to determine their efficacy in reducing long-term proliferation of human UM cell lines derived from primary (Mel285 and Mel270) and metastatic (OMM2.5) UM tumors [35][36][37]. Cells were treated for 96 hours at selected concentrations, treatment was stopped, cells were cultured for another 10 days in fresh complete media and colonies formed visualized with crystal violet staining and counted [38]. Initial screens at 10 -50 µM Figure 1 showed a dose-dependent reduction in UM cell proliferation with all three HDAC6i tested (Figure S1).…”