Abstract
Purpose :
Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase (RTK) that has been shown to influence cell proliferation, migration and invasion in different kinds of cancers. In uveal melanoma (UM), ALK has been observed to be highly expressed in mixed-cell type tumors and in metastasis in. Crizotinib, an ALK and c-Met inhibitor, has shown activity against UM and is being tested in clinical trials. Other ALK inhibitors have yet to be tested against UM. Hence, the aim of this study is to determine the activity of the more selective ALK inhibitors ceritinib and alectinib against UM in vitro.
Methods :
The UM cell lines MEL270 and OMM2.5, derived from a primary tumor and its liver metastatic lesion, respectively, were used. Three ALK inhibitors were tested: crizotinib, ceritinib, and alectinib. The cell counting kit-8 (CCK-8) viability assay was utilized to test the cytotoxicity of ALK inhibitors, with concentrations ranging from 0.1 to 50 uM. Scratch assays with subsequent ImageJ analysis were performed to assess the effect of ALK inhibitors on cell migration. To promote angiogenesis and test the effect of ALK inhibitors on VEGF production, UM cells were grown in a hypoxic (1% oxygen) chamber. Secreted VEGF was quantitated using a sandwich enzyme-linked immunosorbent assay (ELISA). Statistical analysis was done using analysis of variance (ANOVA) for data on cytotoxicity and migration, while Kruskal-Wallis with Dunn’s multiple comparison test was used for data on VEGF secretion.
Results :
Ceritinib was the most cytotoxic ALK inhibitor, reducing half of cellular viability at 3 uM (LC50). Treatment with ceritinib (2 uM) significantly reduced cell migration in both cell lines (P<0.05). Only ceritinib (2 uM) was able to decrease VEGF production in MEL270. All of the ALK inhibitors, however, significantly decreased VEGF production in OMM 2.5 (P<0.05), with crizotinib (0.5 uM) and ceritinib (1.0 uM) effective even at lower concentrations.
Conclusions :
Of the three ALK inhibitors tested in vitro, ceritinib was the most potent, decreasing survival, migration, and VEGF production in both UM cell lines. OMM2.5 was more responsive to ALK inhibition, suggesting that ALK inhibitors may be beneficial in the therapy of metastatic UM disease. Our results support the use of ceritinib in an animal model of UM to optimize dose and timing of administration.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.