Abstract
Purpose :
Uveal melanoma is a deadly, highly metastatic cancer for which there is no molecularly targeted therapy. Transcriptional analysis of uveal melanoma samples showed alterations in transcription of several epigenetic and metabolic genes. Given the known association between mitochondrial function, the epigenome, and oncogenesis, we isolated primary uveal melanocytes from human donors and compared their mitochondrial metabolism to that of uveal melanoma cell lines.
Methods :
Based on prior work, we analyzed the expression patterns of metabolic and epigenetic enzymes of primary uveal melanoma samples using the TCGA database. We successfully isolated and propagated six new primary human uveal melanocyte cell lines. We sequenced the cell lines to ensure no melanoma-associated mutations were present and characterized their growth and morphology compared to established human uveal melanoma cell lines. Using Seahorse, we quantified oxygen consumption rate in basal and proton leak conditions, as well as determined their maximal respiratory capacity and media acidification rate.
Results :
Uveal melanoma transcriptional analysis showed alterations in citrate synthase (CS), ATP-dependent citrate lyase (ACLY), and multiple epigenetic enzymes, including NAD-dependent deacetylases (SIRT1 and SIRT6), histone demethylases (KDM3A/B, JMJD1C), and DNA methyltransferases (DNMT3A/B). Primary uveal melanocytes exhibited highly regular morphology, intense pigmentation, and were positive for melanocyte markers Melan-A and SOX10 and negative for the RPE marker Bestrophin-1. Compared to uveal melanoma, primary uveal melanocytes showed slower growth and altered metabolism. Specifically, primary uveal melanocytes had higher basal oxygen consumption and showed tight mitochondrial coupling. Moreover, their media acidification rate was lower compared with uveal melanoma samples, which showed a more glycolytic profile.
Conclusions :
Transcriptional analysis of uveal melanoma suggests alterations in mitochondrial metabolism and the epigenome. We have shown that primary uveal melanocytes show a distinct metabolic profile from uveal melanoma cell lines, which are highly glycolytic. Taken together, this suggests that uveal melanoma may have an altered epigenome whose further study might uncover new therapeutic targets.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.