Multicellular tumor spheroids of human uveal melanoma induce genes associated with anoikis resistance, lipogenesis, and SSXs.

PURPOSE: Uveal melanoma (UM) has a high propensity for metastatic spread, and approximately 40-50% of patients die of metastatic disease. Metastases can be found at the time of diagnosis but also several years after the tumor has been removed. The survival of disseminated cancer cells is known to be linked to anchorage independence, anoikis resistance, and an adaptive cellular metabolism. The cultivation of cancer cells as multicellular tumor spheroids (MCTS) by anchorage-independent growth enriches for a more aggressive phenotype. The present study examines the differential gene expression of adherent cell cultures, non-adherent MCTS cultures, and uncultured tumor biopsies from three patients with UM. We elucidate the biochemical differences between the culture conditions to find whether the culture of UM as non-adherent MCTS could be linked to an anchorage-independent and more aggressive phenotype, thus unravelling potential targets for treatment of UM dissemination. METHODS: The various culture conditions were evaluated with microarray analysis, quantitative reverse-transcription polymerase chain reaction (qRT-PCR), RNAscope, immunohistochemistry (IHC), and transmission electron microscopy (TEM) followed by gene expression bioinformatics. RESULTS: The MCTS cultures displayed traits associated with anoikis resistance demonstrated by ANGPTL4 upregulation, and a shift toward a lipogenic profile by upregulation of ACOT1 (lipid metabolism), FADS1 (biosynthesis of unsaturated fatty acids), SC4MOL, DHCR7, LSS (cholesterol biosynthesis), OSBPL9 (intracellular lipid receptor), and PLIN2 (lipid storage). Additionally, the present study shows marked upregulation of synovial sarcoma X breakpoint proteins (SSXs), transcriptional repressors related to the Polycomb group (PcG) proteins that modulate epigenetic silencing of genes. CONCLUSIONS: The MCTS cultures displayed traits associated with anoikis resistance, a metabolic shift toward a lipogenic profile, and upregulation of SSXs, related to the PcG proteins.

Fundus Autofluorescence Change as an Early Indicator of Treatment Effect of Brachytherapy for Choroidal Melanomas.

BACKGROUND: Early confirmation of the effect of brachytherapy for choroidal melanoma showing that tumour coverage is valuable. The irradiated retinal pigment epithelium (RPE) commonly develops atrophy. This study compares the fundus autofluorescence (AF) changes to the development of RPE atrophy following brachytherapy. METHODS: Retrospective study of 19 patients treated with 106Ru and 2 with 125I plaques with either a 3- or 6-month follow-up period. Ultra-widefield (UW) composite colour and AF images were obtained with Optomap 200Tx and interpreted as complete, partial, or no RPE changes and complete or partial hyperautofluorescence, hypoautofluorescence, or isoautofluorescence. RESULTS: At the 3-month follow-up, 9 of 13 patients (69%) (95% confidence interval [CI], 0.389-0.896) treated with 106Ru plaques developed complete homogenous hyperautofluorescence surrounding the tumour, but only 1 of 13 (8%) (95% CI, 0.004-0.379) developed complete RPE atrophy at the same time point. Six patients in the 106Ru plaque group had their first follow-up with UW imaging at 6 months. Four of them developed homogenous hyperautofluorescence and none developed complete RPE atrophy around the tumour. The 2 patients treated with 125I did not demonstrate any clear RPE or AF changes. CONCLUSION: The effect of 106Ru plaque treatment on fundus UW imaging is detected as homogenous and well-demarcated hyperautofluorescence before visible RPE atrophy.